freepascal.compiler/rtl/inc/graph/graph.pp

{
    $Id$
    This file is part of the Free Pascal run time library.
    Copyright (c) 1993,99 by the Free Pascal development team

    See the file COPYING.FPC, included in this distribution,
    for details about the copyright.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

 **********************************************************************}
Unit Graph;
{-------------------------------------------------------}
{ Differences with TP Graph unit:                       }
{ -  default putimage and getimage only support a max.  }
{    of 64K colors on screen, because all pixels are    }
{    saved as words.                                    }
{ -  Set RGB Palette is not used, SetPalette must be    }
{    used instead.                                      }
{ -  In the TP graph unit, Clipping is always performed }
{    on strings written with OutText, and this clipping }
{    is done on a character per character basis (for    }
{    example, if ONE part of a character is outside the }
{    viewport , then that character is not written at   }
{    all to the screen. In FPC Pascal, clipping is done }
{    on a PIXEL basis, not a character basis, so part of }
{    characters which are not entirely in the viewport  }
{    may appear on the screen.                          }
{ -  SetTextStyle only conforms to the TP version when  }
{    the correct (and expected) values are used for     }
{    CharSize for stroked fonts (4 = stroked fonts)     }
{ -  InstallUserDriver is not supported, so always      }
{    returns an error.                                  }
{ -  RegisterBGIDriver is not supported, so always      }
{    returns an error.                                  }
{ - DrawPoly XORPut mode is not exactly the same as in  }
{   the TP graph unit.                                  }
{ - FillEllipse does not support XORPut mode with a     }
{   bounded FloodFill. Mode is always CopyPut mode.     }
{ - Imagesize returns a longint instead of a word       }
{ - ImageSize cannot return an error value              }
{-------------------------------------------------------}
{ AUTHORS:                                                                      }
{   Gernot Tenchio      - original version              }
{   Florian Klaempfl    - major updates                 }
{   Pierre Mueller      - major bugfixes                }
{   Carl Eric Codere    - complete rewrite              }
{   Thomas Schatzl      - optimizations,routines and    }
{ Credits (external):       suggestions.                }
{   - Original FloodFill code by                        }
{        Menno Victor van der star                      }
{     (the code has been heavily modified)              }
{-------------------------------------------------------}
{-------------------------------------------------------}
{ For significant speed improvements , is is recommended }
{ that these routines be hooked (otherwise the default,  }
{ slower routines will be used) :                        }
{   HLine()                                              }
{   VLine()                                              }
{   PatternLine()                                        }
{   ClearViewPort()                                      }
{   PutImage()                                           }
{   GetImage()  - ImageSize() should also be changed     }
{   InternalEllipse()                                    }
{   Line()                                               }
{   GetScanLine()                                        }
{--------------------------------------------------------}
{ FPC unit requirements:                                 }
{  All modes should at least have 1 graphics page to     }
{  make it possible to create animation on all supported }
{  systems , this can be done either by double-buffering }
{  yourself in the heap if no hardware is available to do}
{  it.                                                   }
{--------------------------------------------------------}
{ COMPATIBILITY WARNING: Some of the compatibility tests }
{ were done using the CGA and other the VGA drivers.     }
{ Within the BGI drivers themselves the BEHAVIOUR is not }
{ the same, so be warned!!!                              }
{--------------------------------------------------------}
{ History log:                                           }
{   15th February 1999:                                  }
{   + Added support for system font in vertical mode     }
{   + system font is now available for all platforms     }
{   * font support routines now compile                  }
{   * textHeight would not return correct size for system }
{     font                                               }
{   * Alignment of fonts partly fixed                    }
{   17th Feb. 1999:                                      }
{   + First support for stroked fonts                    }
{   18th Feb. 1999:                                      }
{   * bugfix of line drawing which fixes stroked font    }
{     displays.                                          }
{   23rd Feb. 1999:                                      }
{   + Applied Pierre's patches to font                   }
{   + Added scaling of bitmapped fonts                   }
{   + Vertical stroked fonts                             }
{  24th Feb. 1999:                                       }
{   * Scaling of stroked fonts must be done using FPs    }
{     to be 100% compatible with turbo pascal            }
{   + Sped up by 40% stroked font scaling calculations   }
{   + RegisterBGIFont                                    }
{  9th march 1999:                                       }
{   + Starting implementing Fillpoly()                   }
{  15th march 1999:                                      }
{   + SetFillStyle()                                     }
{   + patternLine()                                      }
{   + Bar()                                              }
{   * GraphDefaults would not make the Default color     }
{     of the fill pattern to the Max. Palette entry.     }
{   + SetFillPattern()                                   }
{  20th march 1999:                                      }
{   * GraphDefaults would not reset to the text system   }
{   * DefaultFont would write one character too much to  }
{     the screen                                         }
{   + Sloped thick lines in Line()                       }
{   + Sloped patterned lines in Line()                   }
{   * GraphDefaults would not reset the User Fill pattern}
{     to $ff                                             }
{   + DirectPutPixel takes care of XOR mode writes       }
{     improves speed by about 30% over old method of     }
{     GetPixel XOR CurrentColor                          }
{   * Dashed LineStyle exactly like BP version now       }
{   + Center LineStyle (checked against CGA driver)      }
{   * GraphDefaults() now resets linepattern array       }
{ 1st april  1999:                                       }
{   + First implementation of FillPoly (incomplete)      }
{ 2nd april  1999:                                       }
{   * FillPoly did not Reset PatternLine index           }
{   * FillPoly did not use correct color                 }
{   * PatternLine was writing modes in reverse direction }
{   * PatternLine would not work with non-rectangular    }
{     shapes.                                            }
{   * PatternLine must fill up the ENTIRE pattern,       }
{     with either the foreground or background color.    }
{   * GraphDefaults() would not call SetBkColor()        }
{   * Fixed some memory leaks in FillPoly()              }
{ 11th April  1999:                                      }
{   * PatternLine() was drawing one pixel less then      }
{     requested                                          }
{ 12th April  1999:                                      }
{   + FloodFill - first working implementation           }
{      Horrbly slow even on very fast cpu's              }
{   + Some suggestions of Thomas implemented             }
{ 13th April  1999:                                      }
{   * FloodFill() vertical index was off by one pixel    }
{   * FloodFill() would never draw the last line in the  }
{      list                                              }
{   - Removed ClearViewPort320 which was wrong anyways,  }
{     will need to be implemented later.                 }
{   * PatternLine() would not always restore write mode  }
{   + Circle() uses NormalPut always with NormWidth lines}
{   + FillEllipse() initial version                      }
{   * InternalEllipse() - 0 to 360 now supported as      }
{     angles.                                            }
{ 14th April  1999:                                      }
{   * mod x = and (x-1)(from Thomas Schatzl) gives a     }
{     significant speed improvement.                     }
{ 15th april  1999:                                      }
{   + Arc() ok except for Aspect Ratio, which does not   }
{     give us the correct ratio on a 320x200 screen.     }
{   + Added FillPoly() from Thomas Schatzl               }
{   + More hookable routines                             }
{  16th april  1999:                                     }
{   + Line() checked ok.                                 }
{  17th april  1999:                                     }
{   * GraphDefaults() would not reset CP                 }
{   + GetX(), GetY(), MoveTo() checked for viewports     }
{   * OutTextXY() should not update the CP               }
{   * ClearViewPort() would not update the CP            }
{   * ClearDevice() would not update the CP              }
{   * Sector() would update the CP by calling LineTo     }
{   * Bar3D() would update the CP                        }
{   * PieSlice() would update the CP                     }
{  18th april  1999:                                     }
{   + Clipping algorithm                                 }
{  19th april  1999:                                     }
{   + Adapterinfo structure                              }
{  20th april 1999:                                      }
{   + GetModeName                                        }
{   + GetGraphMode                                       }
{   + GetModeRange                                       }
{--------------------------------------------------------}
{ LEFT TO DO:                                            }
{   - optimize scaling of stroked fonts                  }
{   - optimize InternalEllipse()                         }
{      using linear appx. of sine/cosine tables          }
{   - justification for stroked fonts does not work      }
{   - On Closegraph deallocate all font pointers         }
{--------------------------------------------------------}

{ text.inc will crash on aligned requirement machines.          }
{ (packed record for fontrec)                                   }
{$G+}

Interface


    const
       { error codes }
       grOk =  0;
       grNoInitGraph = -1;
       grNotDetected = -2;
       grFileNotFound = -3;
       grInvalidDriver = -4;
       grNoLoadMem = -5;
       grNoScanMem = -6;
       grNoFloodMem = -7;
       grFontNotFound = -8;
       grNoFontMem = -9;
       grInvalidMode = -10;
       grError = -11;
       grIOerror = -12;
       grInvalidFont = -13;
       grInvalidFontNum = -14;
       grInvalidVersion = -18;


       { Color constants for setpalette }
       black     = 0;
       blue      = 1;
       green     = 2;
       cyan      = 3;
       red       = 4;
       magenta   = 5;
       brown     = 6;
       lightgray = 7;
       darkgray  = 8;
       lightblue = 9;
       lightgreen = 10;
       lightcyan = 11;
       lightred  = 12;
       lightmagenta = 13;
       yellow    = 14;
       white     = 15;

       EGABlack    =  0;
       EGABlue     =  1;
       EGAGreen    =  2;
       EGACyan     =  3;
       EGARed      =  4;
       EGAMagenta  =  5;
       EGALightgray=  7;
       EGABrown    = 20;
       EGADarkgray   = 56;
       EGALightblue  = 57;
       EGALightgreen = 58;
       EGALightcyan  = 59;
       EGALightred   = 60;
       EGALightmagenta=61;
       EGAYellow     = 62;
       EGAWhite      = 63;



       { Line styles for GetLineStyle/SetLineStyle }
       SolidLn = 0;
       DottedLn = 1;
       CenterLn = 2;
       DashedLn = 3;
       UserBitLn = 4;

       NormWidth = 1;
       ThickWidth = 3;

       { Set/GetTextStyle Konstanten: }
       DefaultFont = 0;
       TriplexFont = 1;
       SmallFont = 2;
       SansSerifFont = 3;
       GothicFont = 4;
       ScriptFont = 5;
       SimpleFont = 6;
       TSCRFont = 7;
       LCOMFont = 8;
       EuroFont = 9;
       BoldFont = 10;

       HorizDir = 0;
       VertDir = 1;

       UserCharSize = 0;

       ClipOn = true;
       ClipOff = false;

       { Bar3D constants }
       TopOn = true;
       TopOff = false;

       { fill pattern for Get/SetFillStyle: }
       EmptyFill      = 0;
       SolidFill      = 1;
       LineFill       = 2;
       LtSlashFill    = 3;
       SlashFill      = 4;
       BkSlashFill    = 5;
       LtBkSlashFill  = 6;
       HatchFill      = 7;
       XHatchFill     = 8;
       InterleaveFill = 9;
       WideDotFill    = 10;
       CloseDotFill   = 11;
       UserFill       = 12;

       { bitblt operators  }
       NormalPut     = 0;
       CopyPut       = 0;
       XORPut        = 1;
       OrPut         = 2;
       AndPut        = 3;
       NotPut        = 4;

       { SetTextJustify constants }
       LeftText   = 0;
       CenterText = 1;
       RightText  = 2;

       BottomText = 0;
       TopText    = 2;

       { graphic drivers }
       CurrentDriver = -128;
       Detect        = 0;
       LowRes        = 1;
       HercMono      = 7;
       VGA           = 9;
       VESA          = 10;

       { graph modes }
       Default = 0;

       { VGA Driver modes }
       VGALo   = 0;
       VGAMed  = 1;
       VGAHi   = 2;

       { Hercules mono card }
       HercMonoHi = 0;



       MaxColors   = 255;   { Maximum possible colors using a palette }
                            { otherwise, direct color encoding        }


    type
       RGBRec = packed record
         Red: integer;
         Green: integer;
         Blue : integer;
       end;

       PaletteType = record
             Size   : longint;
             Colors : array[0..MaxColors] of RGBRec;
       end;

       LineSettingsType = record
             linestyle : word;
             pattern : word;
             thickness : word;
       end;

       TextSettingsType = record
             font : word;
             direction : word;
             charsize : word;
             horiz : word;
             vert : word;
       end;

       FillSettingsType = record
             pattern : word;
             color : word;
       end;

       FillPatternType = array[1..8] of byte;

       PointType = record
             x,y : integer;
       end;

       ViewPortType = record
             x1,y1,x2,y2 : integer;
             Clip : boolean;
       end;

       ArcCoordsType = record
             x,y : integer;
             xstart,ystart : integer;
             xend,yend : integer;
       end;


  const
       fillpatternTable : array[0..12] of FillPatternType = (
           ($00,$00,$00,$00,$00,$00,$00,$00),     { background color  }
           ($ff,$ff,$ff,$ff,$ff,$ff,$ff,$ff),     { foreground color  }
           ($ff,$ff,$00,$00,$ff,$ff,$00,$00),     { horizontal lines  }
           ($01,$02,$04,$08,$10,$20,$40,$80),     { slashes           }
           ($07,$0e,$1c,$38,$70,$e0,$c1,$83),     { thick slashes     }
           ($07,$83,$c1,$e0,$70,$38,$1c,$0e),     { thick backslashes }
           ($5a,$2d,$96,$4b,$a5,$d2,$69,$b4),     { backslashes       }
           ($ff,$88,$88,$88,$ff,$88,$88,$88),     { small boxes       }
           ($18,$24,$42,$81,$81,$42,$24,$18),     { rhombus           }
           ($cc,$33,$cc,$33,$cc,$33,$cc,$33),     { wall pattern      }
           ($80,$00,$08,$00,$80,$00,$08,$00),     { wide points       }
           ($88,$00,$22,$00,$88,$00,$22,$00),     { dense points      }
           (0,0,0,0,0,0,0,0)                      { user defined line style }
          );



  { ******************** PROCEDURAL VARIABLES ********************* }
  { * These are hooks which have device specific stuff in them,   * }
  { * therefore to add new modes or to redirect these routines    * }
  { * then declare variables of these types as shown below.       * }
  {-----------------------------------------------------------------}

TYPE


       { This is the standard putpixel routine used by all function }
       { drawing routines, it will use the viewport settings, as    }
       { well as clip, and use the current foreground color to plot }
       { the desired pixel.                                         }
       defpixelproc = procedure(X,Y: Integer);

       { standard plot and get pixel                                }
       getpixelproc = function(X,Y: Integer): word;
       putpixelproc = procedure(X,Y: Integer; Color: Word);

       { clears the viewport, also used to clear the device         }
       clrviewproc  = procedure;

       { putimage procedure, can be hooked to accomplish transparency }
       putimageproc = procedure (X,Y: Integer; var Bitmap; BitBlt: Word);
       getimageproc = procedure(X1,Y1,X2,Y2: Integer; Var Bitmap);
       imagesizeproc= function (X1,Y1,X2,Y2: Integer): longint;

       graphfreememprc = procedure (var P: Pointer; size: word);
       graphgetmemprc  = procedure (var P: pointer; size: word);

       { internal routines -- can be hooked for much faster drawing }

       { draw filled horizontal lines using current color }
       { on entry coordinates are already clipped.        }
       hlineproc = procedure (x, x2,y : integer);
       { on entry coordinates are already clipped.        }
       { draw filled vertical line using current color    }
       vlineproc = procedure (x,y,y2: integer);

       { this routine is used to draw filled patterns for all routines }
       { that require it. (FillPoly, FloodFill, Sector, etc...         }
       { clipping is verified, uses current Fill settings for drawing  }
       patternlineproc = procedure (x1,x2,y: integer);

       { this routine is used to draw all circles/ellipses/sectors     }
       { more info... on this later...                                 }
       ellipseproc = procedure (X,Y: Integer;XRadius: word;
         YRadius:word; stAngle,EndAngle: word);

       { Line routine - draws lines thick/norm widths with current     }
       { color and line style - LINE must be clipped here.             }
       lineproc = procedure (X1, Y1, X2, Y2 : Integer);

       { this routine is used for FloodFill - it returns an entire      }
       { screen scan line with a word for each pixel in the scanline    }
       getscanlineproc = procedure (Y : integer; var data);

       { changes the active display screen where we draw to... }
       setactivepageproc = procedure (page: word);

       { changes the active display screen which we see ... }
       setvisualpageproc = procedure (page: word);

       { this routine actually switches to the desired video mode.     }
       initmodeproc = procedure;

       { this routine is called to save the sate just before a mode set }
       savestateproc = procedure;
       { this routine is called in closegraph to cleanup...             }
       restorestateproc = procedure;

       { This routine is a hook for SetRGBPalette                       }
       setrgbpaletteproc =
         procedure(ColorNum, RedValue, GreenValue, BlueValue: Integer);

       { This routine is a hook for GetRGBPalette                       }
       getrgbpaletteproc =
         procedure(ColorNum: integer; var
            RedValue, GreenValue, BlueValue: Integer);

TYPE
    {-----------------------------------}
    { Linked list for mode information  }
    { This list is set up by one of the }
    { following routines:               }
    { It lists all available resolutions}
    { on this display adapter.          }
    {-----------------------------------}
    {   QueryAdapter()                  }
    {   DetectGraph()                   }
    {   InitGraph()                     }
    {-----------------------------------}
    PModeInfo = ^TModeInfo;
    TModeInfo = record
      DriverNumber: Integer;
      ModeNumber: Integer;
      MaxColor: Longint;            { Maximum colors on screen        }
      PaletteSize : Longint;        { Maximum palette entry we can change }
      XAspect : Integer;            { XAspect ratio correction factor }
      YAspect : Integer;            { YAspect ratio correction factor }
      MaxX: Integer;                { Max-X row                       }
      MaxY: Integer;                { Max. column.                    }
      DirectColor: boolean;         { Is this a direct color mode??   }
      Hardwarepages: byte;          { total number of image pages - 1 }
      ModeName: String[18];
      { necessary hooks ... }
      DirectPutPixel : DefPixelProc;
      GetPixel       : GetPixelProc;
      PutPixel       : PutPixelProc;
      SetRGBPalette  : SetRGBPaletteProc;
      GetRGBPalette  : GetRGBPaletteProc;
      { defaults possible ... }
      SetVisualPage  : SetVisualPageProc;
      SetActivePage  : SetActivePageProc;
      ClearViewPort  : ClrViewProc;
      PutImage       : PutImageProc;
      GetImage       : GetImageProc;
      ImageSize      : ImageSizeProc;
      GetScanLine    : GetScanLineProc;
      Line           : LineProc;
      InternalEllipse: EllipseProc;
      PatternLine    : PatternLineProc;
      HLine          : HLineProc;
      VLine          : VLineProc;
      InitMode       : InitModeProc;
      next: PModeInfo;
    end;



VAR
  DirectPutPixel : DefPixelProc;
  ClearViewPort  : ClrViewProc;
  PutPixel       : PutPixelProc;
  PutImage       : PutImageProc;
  GetImage       : GetImageProc;
  ImageSize      : ImageSizeProc;
  GetPixel       : GetPixelProc;
  SetVisualPage  : SetVisualPageProc;
  SetActivePage  : SetActivePageProc;
  SetRGBPalette  : SetRGBPaletteProc;
  GetRGBPalette  : GetRGBPaletteProc;

  GraphFreeMemPtr: graphfreememprc;
  GraphGetMemPtr : graphgetmemprc;

  GetScanLine    : GetScanLineProc;
  Line           : LineProc;
  InternalEllipse: EllipseProc;
  PatternLine    : PatternLineProc;
  HLine          : HLineProc;
  VLine          : VLineProc;

  SaveVideoState : SaveStateProc;
  RestoreVideoState: RestoreStateProc;


Procedure Closegraph;
procedure SetLineStyle(LineStyle: word; Pattern: word; Thickness: word);
function  GraphErrorMsg(ErrorCode: Integer): string;
Function  GetMaxX: Integer;
Function  GetMaxY: Integer;
Procedure SetViewPort(X1, Y1, X2, Y2: Integer; Clip: Boolean);
Function  GraphResult: Integer;
function  GetModeName(ModeNumber: integer): string;
procedure SetGraphMode(Mode: Integer);
function GetGraphMode: Integer;
function GetMaxMode: word;
procedure RestoreCrtMode;
procedure GetModeRange(GraphDriver: Integer; var LoMode, HiMode: Integer);
Function  GetX: Integer;
Function  GetY: Integer;
procedure GraphDefaults;
procedure ClearDevice;
procedure GetViewSettings(var viewport : ViewPortType);
procedure SetWriteMode(WriteMode : integer);
procedure GetFillSettings(var Fillinfo:Fillsettingstype);
procedure GetFillPattern(var FillPattern:FillPatternType);
procedure GetLineSettings(var ActiveLineInfo : LineSettingsType);
procedure InitGraph(var GraphDriver:Integer;var GraphMode:Integer;const PathToDriver:String);
function InstallUserDriver(Name: string; AutoDetectPtr: Pointer): integer;
function RegisterBGIDriver(driver: pointer): integer;
procedure SetFillStyle(Pattern : word; Color: word);
procedure SetFillPattern(Pattern: FillPatternType; Color: word);
Function GetDriverName: string;
 procedure MoveRel(Dx, Dy: Integer);
 procedure MoveTo(X,Y: Integer);

 procedure SetDirectVideo(DirectAccess: boolean);
 function GetDirectVideo: boolean;

 { -------------------- Color/Palette ------------------------------- }
 procedure SetBkColor(ColorNum: Word);
 function  GetColor: Word;
 function  GetBkColor: Word;
 procedure SetColor(Color: Word);
 function  GetMaxColor: word;

 procedure SetAllPalette(var Palette:PaletteType);
 procedure SetPalette(ColorNum: word; Color: shortint);
 procedure GetPalette(var Palette: PaletteType);
 function GetPaletteSize: integer;
 procedure GetDefaultPalette(var Palette: PaletteType);


 { -------------------- Shapes/Lines -------------------------------- }
 procedure Rectangle(x1,y1,x2,y2:integer);
 procedure Bar(x1,y1,x2,y2:integer);
 procedure Bar3D(x1, y1, x2, y2 : integer;depth : word;top : boolean);
 procedure FillPoly(NumPoints: word; Var PolyPoints);
 procedure DrawPoly(NumPoints : word;var polypoints);
 procedure LineRel(Dx, Dy: Integer);
 procedure LineTo(X,Y : Integer);
 procedure FloodFill(x : integer; y : integer; Border: word);

 { -------------------- Circle related routines --------------------- }
 procedure GetAspectRatio(var Xasp,Yasp : word);
 procedure SetAspectRatio(Xasp, Yasp : word);
 procedure GetArcCoords(var ArcCoords: ArcCoordsType);


 procedure Arc(X,Y : Integer; StAngle,EndAngle,Radius: word);
 procedure PieSlice(X,Y,stangle,endAngle:integer;Radius: Word);
 procedure FillEllipse(X, Y: Integer; XRadius, YRadius: Word);
 procedure Circle(X, Y: Integer; Radius:Word);
 procedure Sector(x, y: Integer; StAngle,EndAngle, XRadius, YRadius: Word);
 procedure Ellipse(X,Y : Integer; stAngle, EndAngle: word; XRadius,
   YRadius: word);

 { --------------------- Text related routines --------------------- }
 function  InstallUserFont(const FontFileName : string) : integer;
 function  RegisterBGIfont(font : pointer) : integer;
 procedure GetTextSettings(var TextInfo : TextSettingsType);
 function  TextHeight(const TextString : string) : word;
 function  TextWidth(const TextString : string) : word;
 procedure SetTextJustify(horiz,vert : word);
 procedure SetTextStyle(font,direction : word;charsize : word);
 procedure SetUserCharSize(Multx,Divx,Multy,Divy : word);

 procedure OutTextXY(x,y : integer;const TextString : string);
 procedure OutText(const TextString : string);



Implementation
{$ifdef fpc}
  {$ifdef go32v2}
    {$define dpmi}
    uses go32;
    Type TDPMIRegisters = go32.registers;
  {$endif go32v2}
{$else fpc}
{$IFDEF DPMI}
uses WinAPI;
{$ENDIF}
{$endif fpc}

{$ifdef logging}
var debuglog: text;

function strf(l: longint): string;
begin
  str(l, strf)
end;

Procedure Log(Const s: String);
Begin
  Append(debuglog);
  Write(debuglog, s);
  Close(debuglog);
End;

Procedure LogLn(Const s: string);
Begin
  Append(debuglog);
  Writeln(debuglog,s);
  Close(debuglog);
End;
{$endif logging}
const
   StdBufferSize = 4096;   { Buffer size for FloodFill }


type


  tinttable = array[0..16383] of integer;
  pinttable = ^tinttable;

  WordArray = Array [0..StdbufferSize] Of word;
  PWordArray = ^WordArray;


const
   { Mask for each bit in byte used to determine pattern }
   BitArray: Array[0..7] of byte =
     ($01,$02,$04,$08,$10,$20,$40,$80);
   RevbitArray: Array[0..7] of byte =
     ($80,$40,$20,$10,$08,$04,$02,$01);




    { pre expanded line patterns }
    { 0 = LSB of byte pattern    }
    { 15 = MSB of byte pattern   }
    LinePatterns: Array[0..15] of BOOLEAN =
     (TRUE,TRUE,TRUE,TRUE,TRUE,TRUE,TRUE,TRUE,
      TRUE,TRUE,TRUE,TRUE,TRUE,TRUE,TRUE,TRUE);

const
  BGIPath : string = '.';


  { Default font 8x8 system from IBM PC }
  {$i fontdata.inc}



var
  CurrentColor:     Word;
  CurrentBkColor: Word;
  CurrentX : Integer;   { viewport relative }
  CurrentY : Integer;   { viewport relative }

  ClipPixels: Boolean;  { Should cliiping be enabled }


  CurrentWriteMode: Integer;


  _GraphResult : Integer;


  LineInfo : LineSettingsType;
  FillSettings: FillSettingsType;

  { information for Text Output routines }
  CurrentTextInfo : TextSettingsType;
  CurrentXRatio: Real;
  CurrentYRatio: Real;
  installedfonts: longint;  { Number of installed fonts }


  StartXViewPort: Integer; { absolute }
  StartYViewPort: Integer; { absolute }
  ViewWidth : Integer;
  ViewHeight: Integer;


  IsGraphMode : Boolean; { Indicates if we are in graph mode or not }


  ArcCall: ArcCoordsType;   { Information on the last call to Arc or Ellipse }


var

  { ******************** HARDWARE INFORMATION ********************* }
  { Should be set in InitGraph once only.                           }
  IntCurrentMode : Integer;
  IntCurrentDriver : Integer;       { Currently loaded driver          }
  XAspect : Integer;
  YAspect : Integer;
  MaxX : Integer;       { Maximum resolution - ABSOLUTE }
  MaxY : Integer;       { Maximum resolution - ABSOLUTE }
  MaxColor : Longint;
  PaletteSize : longint; { Maximum palette entry we can set, usually equal}
                         { maxcolor.                                      }
  HardwarePages : byte;  { maximum number of hardware visual pages        }
  DriverName: String;
  DirectColor : Boolean ; { Is it a direct color mode? }
  ModeList : PModeInfo;
  DirectVideo : Boolean;  { Direct access to video memory? }




{--------------------------------------------------------------------------}
{                                                                          }
{                    LINE AND LINE RELATED ROUTINES                        }
{                                                                          }
{--------------------------------------------------------------------------}

  {$i clip.inc}

  procedure HLineDefault(x,x2,y: integer); far;

   var
    xtmp: integer;
   Begin

    { must we swap the values? }
    if x >= x2 then
      Begin
        xtmp := x2;
        x2 := x;
        x:= xtmp;
      end;
    { First convert to global coordinates }
    X   := X + StartXViewPort;
    X2  := X2 + StartXViewPort;
    Y   := Y + StartYViewPort;
    if ClipPixels then
      Begin
         if LineClipped(x,y,x2,y,StartXViewPort,StartYViewPort,
                StartXViewPort+ViewWidth, StartYViewPort+ViewHeight) then
            exit;
      end;
    for x:= x to x2 do
      DirectPutPixel(X,Y);
   end;


  procedure VLineDefault(x,y,y2: integer); far;

   var
    Col: word;
    ytmp: integer;
  Begin
    { must we swap the values? }
    if y >= y2 then
     Begin
       ytmp := y2;
       y2 := y;
       y:= ytmp;
     end;
    { First convert to global coordinates }
    X   := X + StartXViewPort;
    Y2  := Y2 + StartYViewPort;
    Y   := Y + StartYViewPort;
    if ClipPixels then
      Begin
         if LineClipped(x,y,x,y2,StartXViewPort,StartYViewPort,
                StartXViewPort+ViewWidth, StartYViewPort+ViewHeight) then
            exit;
      end;
    for y := y to y2 do Directputpixel(x,y)
  End;


  procedure LineDefault(X1, Y1, X2, Y2: Integer); far;

  var X, Y :           Integer;
      deltax, deltay : Integer;
      d, dinc1, dinc2: Integer;
      xinc1          : Integer;
      xinc2          : Integer;
      yinc1          : Integer;
      yinc2          : Integer;
      i, j           : Integer;
      Flag           : Boolean; { determines pixel direction in thick lines }
      NumPixels      : Integer;
      PixelCount     : Integer;
      OldCurrentColor: Word;
      swtmp          : integer;
      TmpNumPixels   : integer;
 begin
{******************************************}
{  SOLID LINES                             }
{******************************************}
  if lineinfo.LineStyle = SolidLn then
    Begin
       { we separate normal and thick width for speed }
       { and because it would not be 100% compatible  }
       { with the TP graph unit otherwise             }
       if y1 = y2 then
        Begin
     {******************************************}
     {  SOLID LINES HORIZONTAL                  }
     {******************************************}
          if lineinfo.Thickness=NormWidth then
            hline(x1,x2,y2)
          else
            begin
               { thick width }
               hline(x1,x2,y2-1);
               hline(x1,x2,y2);
               hline(x2,x2,y2+1);
            end;
        end
    else
    if x1 = x2 then
        Begin
     {******************************************}
     {  SOLID LINES VERTICAL                    }
     {******************************************}
          if lineinfo.Thickness=NormWidth then
            vline(x1,y1,y2)
          else
            begin
            { thick width }
              vline(x1-1,y1,y2);
              vline(x1,y1,y2);
              vline(x1+1,y1,y2);
            end;
        end
    else
    begin
     { Convert to global coordinates. }
     x1 := x1 + StartXViewPort;
     x2 := x2 + StartXViewPort;
     y1 := y1 + StartYViewPort;
     y2 := y2 + StartYViewPort;
     { if fully clipped then exit... }
     if ClipPixels then
       begin
       if LineClipped(x1,y1,x2,y2,StartXViewPort, StartYViewPort,
           StartXViewPort+ViewWidth, StartYViewPort+ViewHeight) then
              exit;
       end;
     {******************************************}
     {  SLOPED SOLID LINES                      }
     {******************************************}
           oldCurrentColor :=
           CurrentColor;
           { Calculate deltax and deltay for initialisation }
           deltax := abs(x2 - x1);
           deltay := abs(y2 - y1);

          { Initialize all vars based on which is the independent variable }
          if deltax >= deltay then
            begin

             Flag := FALSE;
             { x is independent variable }
             numpixels := deltax + 1;
             d := (2 * deltay) - deltax;
             dinc1 := deltay Shl 1;
             dinc2 := (deltay - deltax) shl 1;
             xinc1 := 1;
             xinc2 := 1;
             yinc1 := 0;
             yinc2 := 1;
            end
          else
            begin

             Flag := TRUE;
             { y is independent variable }
             numpixels := deltay + 1;
             d := (2 * deltax) - deltay;
             dinc1 := deltax Shl 1;
             dinc2 := (deltax - deltay) shl 1;
             xinc1 := 0;
             xinc2 := 1;
             yinc1 := 1;
             yinc2 := 1;
            end;

         { Make sure x and y move in the right directions }
         if x1 > x2 then
           begin
            xinc1 := - xinc1;
            xinc2 := - xinc2;
           end;
         if y1 > y2 then
          begin
           yinc1 := - yinc1;
           yinc2 := - yinc2;
          end;

         { Start drawing at <x1, y1> }
         x := x1;
         y := y1;


         If LineInfo.Thickness=NormWidth then

          Begin

            { Draw the pixels }
            for i := 1 to numpixels do
              begin
                DirectPutPixel(x, y);
                if d < 0 then
                  begin
                   d := d + dinc1;
                   x := x + xinc1;
                   y := y + yinc1;
                  end
                else
                  begin
                   d := d + dinc2;
                   x := x + xinc2;
                   y := y + yinc2;
                  end;
                  CurrentColor := OldCurrentColor;
             end;
          end
         else
         { Thick width lines }
          begin
            { Draw the pixels }
            for i := 1 to numpixels do
               begin
                { all depending on the slope, we can determine         }
                { in what direction the extra width pixels will be put }
                If Flag then
                  Begin
                    DirectPutPixel(x-1,y);
                    DirectPutPixel(x,y);
                    DirectPutPixel(x+1,y);
                  end
                else
                  Begin
                    DirectPutPixel(x, y-1);
                    DirectPutPixel(x, y);
                    DirectPutPixel(x, y+1);
                  end;
                if d < 0 then
                  begin
                    d := d + dinc1;
                    x := x + xinc1;
                    y := y + yinc1;
                  end
                else
                  begin
                    d := d + dinc2;
                    x := x + xinc2;
                    y := y + yinc2;
                  end;
                CurrentColor := OldCurrentColor;
               end;
          end;
        end;
  end
   else
{******************************************}
{  begin patterned lines                   }
{******************************************}
    Begin
      { Convert to global coordinates. }
      x1 := x1 + StartXViewPort;
      x2 := x2 + StartXViewPort;
      y1 := y1 + StartYViewPort;
      y2 := y2 + StartYViewPort;
      { if fully clipped then exit... }
      if ClipPixels then
       begin
       if LineClipped(x1,y1,x2,y2,StartXViewPort, StartYViewPort,
           StartXViewPort+ViewWidth, StartYViewPort+ViewHeight) then
              exit;
       end;

      OldCurrentColor := CurrentColor;
      PixelCount:=0;
      if y1 = y2 then
            Begin
             { Check if we must swap }
         if x1 >= x2 then
               Begin
                 swtmp := x1;
                 x1 := x2;
                 x2 := swtmp;
               end;
         if LineInfo.Thickness = NormWidth then
              Begin
               for PixelCount:=x1 to x2 do
                     { optimization: PixelCount mod 16 }
                     if LinePatterns[PixelCount and 15] = TRUE then
                      begin
                        DirectPutPixel(PixelCount,y2);
                      end;
              end
             else
              Begin
               for i:=-1 to 1 do
                     Begin
                       for PixelCount:=x1 to x2 do
                         { Optimization from Thomas - mod 16 = and 15 }
                         {this optimization has been performed by the compiler
                          for while as well (JM)}
                         if LinePatterns[PixelCount and 15] = TRUE then
                           begin
                                 DirectPutPixel(PixelCount,y2+i);
                           end;
                     end;
              end;
        end
      else
      if x1 = x2 then
           Begin
            { Check if we must swap }
            if y1 >= y2 then
              Begin
                swtmp := y1;
                y1 := y2;
                y2 := swtmp;
              end;
            if LineInfo.Thickness = NormWidth then
              Begin
                for PixelCount:=y1 to y2 do
                    { compare if we should plot a pixel here , compare }
                    { with predefined line patterns...                 }
                    if LinePatterns[PixelCount and 15] = TRUE then
                      begin
                    DirectPutPixel(x1,PixelCount);
                      end;
              end
            else
              Begin
                for i:=-1 to 1 do
                     Begin
                       for PixelCount:=y1 to y2 do
                       { compare if we should plot a pixel here , compare }
                       { with predefined line patterns...                 }
                         if LinePatterns[PixelCount and 15] = TRUE then
                           begin
                             DirectPutPixel(x1+i,PixelCount);
                           end;
                     end;
              end;
           end
      else
           Begin
             oldCurrentColor := CurrentColor;
             { Calculate deltax and deltay for initialisation }
             deltax := abs(x2 - x1);
             deltay := abs(y2 - y1);

             { Initialize all vars based on which is the independent variable }
             if deltax >= deltay then
               begin

                 Flag := FALSE;
                 { x is independent variable }
                 numpixels := deltax + 1;
                 d := (2 * deltay) - deltax;
                 dinc1 := deltay Shl 1;
                 dinc2 := (deltay - deltax) shl 1;
                 xinc1 := 1;
                 xinc2 := 1;
                 yinc1 := 0;
                 yinc2 := 1;
              end
            else
              begin

                Flag := TRUE;
                { y is independent variable }
                numpixels := deltay + 1;
                d := (2 * deltax) - deltay;
                dinc1 := deltax Shl 1;
                dinc2 := (deltax - deltay) shl 1;
                xinc1 := 0;
                xinc2 := 1;
                yinc1 := 1;
                yinc2 := 1;
              end;

            { Make sure x and y move in the right directions }
            if x1 > x2 then
              begin
                xinc1 := - xinc1;
                xinc2 := - xinc2;
              end;
            if y1 > y2 then
              begin
                yinc1 := - yinc1;
                yinc2 := - yinc2;
              end;

            { Start drawing at <x1, y1> }
            x := x1;
            y := y1;

            If LineInfo.Thickness=ThickWidth then

             Begin
               TmpNumPixels := NumPixels-1;
               { Draw the pixels }
               for i := 0 to TmpNumPixels do
                 begin
                     { all depending on the slope, we can determine         }
                     { in what direction the extra width pixels will be put }
                       If Flag then
                          Begin
                            { compare if we should plot a pixel here , compare }
                            { with predefined line patterns...                 }
                            if LinePatterns[i and 15] = TRUE then
                              begin
                                DirectPutPixel(x-1,y);
                                DirectPutPixel(x,y);
                                DirectPutPixel(x+1,y);
                              end;
                          end
                       else
                          Begin
                            { compare if we should plot a pixel here , compare }
                        { with predefined line patterns...                 }
                            if LinePatterns[i and 15] = TRUE then
                             begin
                               DirectPutPixel(x,y-1);
                               DirectPutPixel(x,y);
                               DirectPutPixel(x,y+1);
                             end;
                          end;
                   if d < 0 then
                         begin
                           d := d + dinc1;
                           x := x + xinc1;
                           y := y + yinc1;
                         end
                   else
                         begin
                   d := d + dinc2;
                   x := x + xinc2;
                   y := y + yinc2;
                         end;
                end;
            end
           else
            Begin
             { instead of putting in loop , substract by one now }
             TmpNumPixels := NumPixels-1;
            { NormWidth }
             for i := 0 to TmpNumPixels do
             begin
                  if LinePatterns[i and 15] = TRUE then
                    begin
                          DirectPutPixel(x,y);
                    end;
             if d < 0 then
                 begin
                   d := d + dinc1;
                   x := x + xinc1;
                   y := y + yinc1;
                 end
             else
                 begin
                   d := d + dinc2;
                   x := x + xinc2;
                   y := y + yinc2;
                 end;
             end;
            end
        end;
{******************************************}
{  end patterned lines                     }
{******************************************}
       { restore color }
       CurrentColor:=OldCurrentColor;
   end;
 end;  { Line }


  {********************************************************}
  { Procedure InternalEllipse()                            }
  {--------------------------------------------------------}
  { This routine first calculates all points required to   }
  { draw a circle to the screen, and stores the points     }
  { to display in a buffer before plotting them. The       }
  { aspect ratio of the screen is taken into account when  }
  { calculating the values.                                }
  {--------------------------------------------------------}
  { INPUTS: X,Y : Center coordinates of Ellipse.           }
  {  XRadius - X-Axis radius of ellipse.                   }
  {  YRadius - Y-Axis radius of ellipse.                   }
  {  stAngle, EndAngle: Start angle and end angles of the  }
  {  ellipse (used for partial ellipses and circles)       }
  {--------------------------------------------------------}
  { NOTE: - uses the current write mode.                   }
  {       - Angles must both be between 0 and 360          }
  {********************************************************}

  Procedure InternalEllipseDefault(X,Y: Integer;XRadius: word;
    YRadius:word; stAngle,EndAngle: word); far;
   var
    i:integer;
    xpt: pinttable;
    ypt: pinttable;
    j,Delta:real;
    NumOfPixels: longint;
    NumOfPix: Array[0..2] of longint;
    count: longint;
    ConvFac,TempTerm: real;
    aval,bval: integer;
    OldcurrentColor: word;
    TmpAngle: word;
    DeltaAngle: word;
  Begin
   If xradius = 0 then inc(x);
   if yradius = 0 then inc(y);
   inc(xradius);
   inc(yradius);
   { check if valid angles }
   stangle := stAngle mod 361;
   EndAngle := EndAngle mod 361;
   { if impossible angles then swap them! }
   if Endangle < StAngle then
     Begin
       TmpAngle:=EndAngle;
       EndAngle:=StAngle;
       Stangle:=TmpAngle;
     end;
   { calculate difference of angle now so we don't always have to calculate it }
   DeltaAngle:= EndAngle-StAngle;
   i:=0;
   if LineInfo.Thickness=NormWidth then
     Begin
       { approximate the number of pixels required by using the circumference }
       { equation of an ellipse.                                              }
       NumOfPixels:=8*Round(2.5*sqrt((sqr(XRadius)+sqr(YRadius)) div 2));
       GetMem(xpt,NumOfpixels*sizeof(word));
       GetMem(ypt,NumOfPixels*sizeof(word));
       { Calculate the angle precision required }
       Delta := DeltaAngle / (NumOfPixels);
       { Adjust for screen aspect ratio }
       XRadius:=(longint(XRadius)*10000) div XAspect;
       YRadius:=(longint(YRadius)*10000) div YAspect;
       { Initial counter value }
       j:=Delta+StAngle;
       { removed from inner loop to make faster }
       ConvFac:=Pi/180.0;
       Repeat
             { this used by both sin and cos }
             TempTerm := j*ConvFac;
             { Calculate points }
             xpt^[i]:=round(XRadius*Cos(TempTerm));
         { calculate the value of y }
             ypt^[i]:=round(YRadius*Sin(TempTerm+Pi));
             j:=j+Delta;
             inc(i);
       Until j > DeltaAngle;
     end
   else
   {******************************************}
   {  CIRCLE OR ELLIPSE WITH THICKNESS=3      }
   {******************************************}
    Begin
      NumOfPix[1]:=8*Round(2.5*sqrt((sqr(XRadius)+sqr(YRadius)) div 2));
      NumOfPix[0]:=8*Round(2.5*sqrt((sqr(XRadius-1)+sqr(YRadius-1)) div 2));
      NumOfPix[2]:=8*Round(2.5*sqrt((sqr(XRadius+1)+sqr(YRadius+1)) div 2));
      GetMem(xpt,(NumOfPix[1]+NumOfPix[2]+NumOfPix[0])*sizeof(word));
      GetMem(ypt,(NumOfPix[1]+NumOfPix[2]+NumOfPix[0])*sizeof(word));
      { removed from inner loop to make faster }
      ConvFac:=Pi/180.0;
      for Count:=0 to 2 do
            Begin
             aval:=XRadius+Count-1;
             bval:=YRadius+Count-1;
             Delta := DeltaAngle / (NumOfPix[Count]);
             aval:= (longint(aval)*10000) div XAspect;
             bval:= (longint(bval)*10000) div YAspect;
             j:=Delta+Stangle;
             Repeat
               { this used by both sin and cos }
               TempTerm := j*ConvFac;
               xpt^[i]:=round((aval)*Cos(TempTerm));
               { calculate the value of y }
               ypt^[i]:=round(bval*Sin(TempTerm+Pi));
               j:=j+Delta;
               inc(i);
             Until j > DeltaAngle;
            end;
    end;
   {******************************************}
   {  NOW ALL PIXEL POINTS ARE IN BUFFER      }
   {  plot them all to the screen             }
   {******************************************}
   Count:=0;
   OldcurrentColor:=currentColor;
   Repeat
     PutPixel(xpt^[Count]+X,ypt^[Count]+Y,CurrentColor);
     inc(count);
   until Count>=i;

   { Get End and Start points into the ArcCall information record }
   ArcCall.X := X;
   ArcCall.Y := Y;
   ArcCall.XStart := xpt^[0] + X;
   ArcCall.YStart := ypt^[0] + Y;
   ArcCall.XEnd := xpt^[Count-1] + X;
   ArcCall.YEnd := ypt^[Count-1] + Y;
   CurrentColor:=OldCurrentColor;
   if LineInfo.Thickness=NormWidth then
     Begin
       Freemem(xpt,NumOfPixels*sizeof(word));
       Freemem(ypt,NumOfPixels*sizeof(word));
     end
   else
     Begin
       FreeMem(xpt,(NumOfPix[1]+NumOfPix[2]+NumOfPix[0])*sizeof(word));
       FreeMem(ypt,(NumOfPix[1]+NumOfPix[2]+NumOfPix[0])*sizeof(word));
     end;
  end;


  {********************************************************}
  { Procedure InternalEllipse()                            }
  {--------------------------------------------------------}
  { This routine first calculates all points required to   }
  { draw a circle to the screen, and stores the points     }
  { to display in a buffer before plotting them. The       }
  { aspect ratio of the screen is taken into account when  }
  { calculating the values.                                }
  {--------------------------------------------------------}
  { INPUTS: X,Y : Center coordinates of Ellipse.           }
  {  XRadius - X-Axis radius of ellipse.                   }
  {  YRadius - Y-Axis radius of ellipse.                   }
  {  stAngle, EndAngle: Start angle and end angles of the  }
  {  ellipse (used for partial ellipses and circles)       }
  {--------------------------------------------------------}
  { NOTE: - uses the current write mode.                   }
  {       - Angles must both be between 0 and 360          }
  {********************************************************}
(*
Procedure InternalEllipseDefault (x, y : integer;
    xradius, yradius, stAngle, EndAngle : Word); far
{ Draw an ellipse arc. Crude but it works (anyone have a better one?) }
Var
  aSqr, bSqr, twoaSqr, twobSqr, xa, ya, twoXbSqr, twoYaSqr, error : LongInt;
  Alpha : Real;
const
  RadToDeg = 180/Pi;


Procedure PlotPoints;

var
 i,j: integer;
 xm, ym: integer;
 xp, yp: integer;
Begin
   ym := y-ya;
   yp := y+ya;
   xm := x-xa;
   xp := x+xa;
   if LineInfo.Thickness = Normwidth then
     Begin
       If (Alpha>=StAngle) And (Alpha<=EndAngle) then
          PutPixel (xm,ym, CurrentColor);
       If (180-Alpha>=StAngle) And (180-Alpha<=EndAngle) then
          PutPixel (xm,yp, CurrentColor);
       If (180+Alpha>=StAngle) And (180+Alpha<=EndAngle) then
          PutPixel (xp,yp, CurrentColor);
       If (360-Alpha>=StAngle) And (360-Alpha<=EndAngle) then
          PutPixel (xp,ym, CurrentColor);
     end
   else
     Begin
       If (Alpha>=StAngle) And (Alpha<=EndAngle) then
          for i:=-1 to 1 do
            for j:=-1 to 1 do
              PutPixel (xm+i,ym+j, CurrentColor);
       If (180-Alpha>=StAngle) And (180-Alpha<=EndAngle) then
          for i:=-1 to 1 do
            for j:=-1 to 1 do
              PutPixel (xm+i,yp+j, CurrentColor);
       If (180+Alpha>=StAngle) And (180+Alpha<=EndAngle) then
          for i:=-1 to 1 do
            for j:=-1 to 1 do
              PutPixel (xp+i,yp+j, CurrentColor);
       If (360-Alpha>=StAngle) And (360-Alpha<=EndAngle) then
          for i:=-1 to 1 do
            for j:=-1 to 1 do
              PutPixel (xp+i,ym+j, CurrentColor);
     end;
End;

Begin
  StAngle:=StAngle MOD 361;
  EndAngle:=EndAngle MOD 361;
  StAngle := StAngle + 270;
  EndAngle := EndAngle + 270;
  If StAngle>EndAngle then
  Begin
    StAngle:=StAngle Xor EndAngle; EndAngle:=EndAngle Xor StAngle; StAngle:=EndAngle Xor StAngle;
  End;
  { Adjust for screen aspect ratio }
  XRadius:=(longint(XRadius)*10000) div XAspect;
  YRadius:=(longint(YRadius)*10000) div YAspect;
  aSqr:=LongInt (xradius)*LongInt (xradius);
  bSqr:=LongInt (yradius)*LongInt (yradius);
  twoaSqr:=2*aSqr;
  twobSqr:=2*bSqr;
  xa:=0;
  ya:=yradius;
  twoXbSqr:=0;
  twoYaSqr:=ya*twoaSqr;
  error:=-ya*aSqr;
  While twoXbSqr<=twoYaSqr Do Begin
    If ya=0 then Alpha:=90 Else Alpha:=RadToDeg*Arctan (xa/ya); { Crude but it works }
    PlotPoints;
    Inc (xa);
    Inc (twoXbSqr,twobSqr);
    Inc (error,twoXbSqr-bSqr);
    If error>=0 then Begin
      Dec (ya);
      Dec (twoYaSqr,twoaSqr);
      Dec (error,twoYaSqr);
    End;
  End;
  xa:=xradius;
  ya:=0;
  twoXbSqr:=xa*twobSqr;
  twoYaSqr:=0;
  error:=-xa*bSqr;
  While twoXbSqr>twoYaSqr Do Begin
    If ya=0 then Alpha:=90 Else Alpha:=RadToDeg*Arctan (xa/ya);
    PlotPoints;
    Inc (ya);
    Inc (twoYaSqr,twoaSqr);
    Inc (error,twoYaSqr-aSqr);
    If error>=0 then Begin
      Dec (xa);
      Dec (twoXbSqr,twobSqr);
      Dec (error,twoXbSqr);
    End;
  End;
End;
  *)
  procedure PatternLineDefault(x1,x2,y: integer); far;
  {********************************************************}
  { Draws a horizontal patterned line according to the     }
  { current Fill Settings.                                 }
  {********************************************************}
  { Important notes:                                       }
  {  - CurrentColor must be set correctly before entering  }
  {    this routine.                                       }
  {********************************************************}
   var
    NrIterations: Integer;
    i           : Integer;
    j           : Integer;
    TmpFillPattern : byte;
    OldWriteMode : word;
    OldCurrentColor : word;
   begin
     { convert to global coordinates ... }
     x1 := x1 + StartXViewPort;
     x2 := x2 + StartXViewPort;
     y  := y + StartYViewPort;
     { if line was fully clipped then exit...}
     if LineClipped(x1,y,x2,y,StartXViewPort,StartYViewPort,
        StartXViewPort+ViewWidth, StartYViewPort+ViewHeight) then
         exit;

     OldWriteMode := CurrentWriteMode;
     CurrentWriteMode := NormalPut;

     { number of times to go throuh the 8x8 pattern }
     NrIterations := abs(x2 - x1+1) div 8;
     Inc(NrIterations);


     { Get the current pattern }
     TmpFillPattern := FillPatternTable
{       [FillSettings.Pattern][(((y+viewport.x1) and $7)+1];}
       [FillSettings.Pattern][(y and $7)+1];

     if FillSettings.Pattern = EmptyFill then
       begin
         OldCurrentColor := CurrentColor;
         CurrentColor := CurrentBkColor;
{ hline converts the coordinates to global ones, but that has been done }
{ already here!!! Convert them bak to local ones... (JM)                }
         HLine(x1-StartXViewPort,x2-StartXViewPort,y-StartYViewPort);
         CurrentColor := OldCurrentColor;
       end
     else
     if  FillSettings.Pattern = SolidFill then
       begin
         HLine(x1-StartXViewPort,x2-StartXViewPort,y-StartYViewPort);
       end
     else
       begin
         For i:= 0 to NrIterations do
           Begin
             for j:=0 to 7 do
                  Begin
                          { x1 mod 8 }
                  if RevBitArray[x1 and 7] and TmpFillPattern <> 0 then
                     DirectPutpixel(x1,y)
                  else
                    begin
                          { According to the TP graph manual, we overwrite everything }
                          { which is filled up - checked against VGA and CGA drivers  }
                          { of TP.                                                    }
                          OldCurrentColor := CurrentColor;
                          CurrentColor := CurrentBkColor;
                          DirectPutPixel(x1,y);
                          CurrentColor := OldCurrentColor;
                    end;
                  Inc(x1);
                  if x1 > x2 then
                   begin
                         CurrentWriteMode := OldWriteMode;
                         exit;
                   end;
                 end;
           end;
        end;
     CurrentWriteMode := OldWriteMode;
   end;




  procedure LineRel(Dx, Dy: Integer);

   Begin
     Line(CurrentX, CurrentY, CurrentX + Dx, CurrentY + Dy);
     CurrentX := CurrentX + Dx;
     CurrentY := CurrentY + Dy;
   end;


  procedure LineTo(x,y : Integer);

   Begin
     Line(CurrentX, CurrentY, X, Y);
     CurrentX := X;
     CurrentY := Y;
   end;




  procedure Rectangle(x1,y1,x2,y2:integer);

   begin
     { Do not draw the end points }
     Line(x1,y1,x2-1,y1);
     Line(x1,y1+1,x1,y2);
     Line(x2,y1,x2,y2-1);
     Line(x1+1,y2,x2,y2);
   end;


  procedure GetLineSettings(var ActiveLineInfo : LineSettingsType);

   begin
    Activelineinfo:=Lineinfo;
   end;


  procedure SetLineStyle(LineStyle: word; Pattern: word; Thickness: word);

   var
    i: byte;
    j: byte;

   Begin
    if (LineStyle > UserBitLn) or ((Thickness <> Normwidth) and (Thickness <> ThickWidth)) then
      _GraphResult := grError
    else
      begin
       LineInfo.Thickness := Thickness;
       LineInfo.LineStyle := LineStyle;
       case LineStyle of
            UserBitLn: Lineinfo.Pattern := pattern;
            SolidLn:   Lineinfo.Pattern  := $ffff;  { ------- }
            DashedLn : Lineinfo.Pattern := $F8F8;   { -- -- --}
            DottedLn:  LineInfo.Pattern := $CCCC;   { - - - - }
            CenterLn: LineInfo.Pattern :=  $FC78;   { -- - -- }
       end; { end case }
       { setup pattern styles }
       j:=16;
       for i:=0 to 15 do
        Begin
         dec(j);
         { bitwise mask for each bit in the word }
         if (word($01 shl i) AND LineInfo.Pattern) <> 0 then
               LinePatterns[j]:=TRUE
             else
               LinePatterns[j]:=FALSE;
        end;
      end;
   end;




{--------------------------------------------------------------------------}
{                                                                          }
{                    VIEWPORT RELATED ROUTINES                             }
{                                                                          }
{--------------------------------------------------------------------------}


Procedure ClearViewPortDefault; far;
var
 j: integer;
 OldWriteMode, OldCurColor: word;
 LineSets : LineSettingsType;
Begin
  { CP is always RELATIVE coordinates }
  CurrentX := 0;
  CurrentY := 0;

  { Save all old settings }
  OldCurColor := CurrentColor;
  CurrentColor:=CurrentBkColor;
  OldWriteMode:=CurrentWriteMode;
  GetLineSettings(LineSets);
  { reset to normal line style...}
  SetLineStyle(SolidLn, 0, NormWidth);

  { routines are relative here...}
  for J:=0 to ViewHeight do
       HLine(0, ViewWidth, J);

  { restore old settings...}
  SetLineStyle(LineSets.LineStyle, LineSets.Pattern, LineSets.Thickness);
  CurrentColor := OldCurColor;
  CurrentWriteMode := OldWriteMode;
end;


Procedure SetViewPort(X1, Y1, X2, Y2: Integer; Clip: Boolean);
Begin
  if (X1 > GetMaxX) or (X2 > GetMaxX) or (X1 > X2) or (X1 < 0) then
  Begin
    _GraphResult := grError;
    exit;
  end;
  if (Y1 > GetMaxY) or (Y2 > GetMaxY) or (Y1 > Y2) or (Y1 < 0) then
  Begin
    _GraphResult := grError;
    exit;
  end;
  { CP is always RELATIVE coordinates }
  CurrentX := 0;
  CurrentY := 0;
  StartXViewPort := X1;
  StartYViewPort := Y1;
  ViewWidth :=  X2-X1;
  ViewHeight:=  Y2-Y1;
  ClipPixels := Clip;
end;


procedure GetViewSettings(var viewport : ViewPortType);
begin
  ViewPort.X1 := StartXViewPort;
  ViewPort.Y1 := StartYViewPort;
  ViewPort.X2 := ViewWidth + StartXViewPort;
  ViewPort.Y2 := ViewHeight + StartYViewPort;
  ViewPort.Clip := ClipPixels;
end;

procedure ClearDevice;
var
  ViewPort: ViewPortType;
begin
  { Reset the CP }
  CurrentX := 0;
  CurrentY := 0;
  { save viewport }
  ViewPort.X1 :=  StartXviewPort;
  ViewPort.X2 :=  ViewWidth - StartXViewPort;
  ViewPort.Y1 :=  StartYViewPort;
  ViewPort.Y2 :=  ViewHeight - StartYViewPort;
  ViewPort.Clip := ClipPixels;
  { put viewport to full screen }
  StartXViewPort := 0;
  ViewHeight := MaxY;
  StartYViewPort := 0;
  ViewWidth := MaxX;
  ClipPixels := TRUE;
  ClearViewPort;
  { restore old viewport }
  StartXViewPort := ViewPort.X1;
  ViewWidth := ViewPort.X2-ViewPort.X1;
  StartYViewPort := ViewPort.Y1;
  ViewHeight := ViewPort.Y2-ViewPort.Y1;
  ClipPixels := ViewPort.Clip;
end;



{--------------------------------------------------------------------------}
{                                                                          }
{                      BITMAP PUT/GET ROUTINES                             }
{                                                                          }
{--------------------------------------------------------------------------}


  Procedure GetScanlineDefault (Y : Integer; Var Data); far;
  {**********************************************************}
  { Procedure GetScanLine()                                  }
  {----------------------------------------------------------}
  { Returns the full scanline of the video line of the Y     }
  { coordinate. The values are returned in a WORD array      }
  { each WORD representing a pixel of the specified scanline }
  { note: we only need the pixels inside the ViewPort! (JM)  }
  {**********************************************************}


  Var
    x : Integer;
  Begin
     For x:=0 to ViewWidth Do Begin
       WordArray(Data)[x]:=GetPixel(x, y);
     End;
  End;



Function DefaultImageSize(X1,Y1,X2,Y2: Integer): longint; far;
Begin
  { each pixel uses two bytes, to enable modes with colors up to 64K }
  { to work.                                                         }
  DefaultImageSize := 12 + (((X2-X1)*(Y2-Y1))*2);
end;

Procedure DefaultPutImage(X,Y: Integer; var Bitmap; BitBlt: Word); far;
type
  pt = array[0..32000] of word;
  ptw = array[0..3] of longint;
var
  color: word;
  i,j: Integer;
  Y1,X1: Integer;
  k: integer;
Begin
  X1:= ptw(Bitmap)[0]+X; { get width and adjust end coordinate accordingly }
  Y1:= ptw(Bitmap)[1]+Y; { get height and adjust end coordinate accordingly }
  k:= 12; { Three reserved longs at start of bitmap }
  for j:=Y to Y1 do
   Begin
     for i:=X to X1 do
      begin
            case BitBlt of
{$R-}
         CopyPut: color:= pt(Bitmap)[k];  { also = normalput }
             XORPut: color:= pt(Bitmap)[k] XOR GetPixel(i,j);
             OrPut: color:= pt(Bitmap)[k] OR GetPixel(i,j);
             AndPut: color:= pt(Bitmap)[k] AND GetPixel(i,j);
             NotPut: color:= not pt(Bitmap)[k];
{$ifdef debug}
{$R+}
{$endif debug}
           end;
           putpixel(i,j,color);
           Inc(k);
     end;
   end;
end;


Procedure DefaultGetImage(X1,Y1,X2,Y2: Integer; Var Bitmap); far;
type
  pt = array[0..32000] of word;
  ptw = array[0..3] of longint;
var
  i,j: integer;
  k: longint;
Begin
  k:= 12; { Three reserved longs at start of bitmap }
  for j:=Y1 to Y2 do
   Begin
     for i:=X1 to X2 do
      begin
{$R-}
            pt(Bitmap)[k] :=getpixel(i,j);
{$ifdef debug}
{$R+}
{$endif debug}
            Inc(k);
      end;
   end;
   ptw(Bitmap)[0] := X2-X1;   { First longint  is width  }
   ptw(Bitmap)[1] := Y2-Y1;   { Second longint is height }
   ptw(bitmap)[2] := 0;       { Third longint is reserved}
end;






  Procedure GetArcCoords(var ArcCoords: ArcCoordsType);
   Begin
     ArcCoords.X := ArcCall.X;
     ArcCoords.Y := ArcCall.Y;
     ArcCoords.XStart := ArcCall.XStart;
     ArcCoords.YStart := ArcCall.YStart;
     ArcCoords.XEnd := ArcCall.XEnd;
     ArcCoords.YEnd := ArcCall.YEnd;
   end;


  procedure SetVisualPageDefault(page : word); far;
   begin
   end;


  procedure SetActivePageDefault(page : word); far;
   begin
   end;


  Procedure DefaultHooks;
  {********************************************************}
  { Procedure DefaultHooks()                               }
  {--------------------------------------------------------}
  { Resets all hookable routine either to nil for those    }
  { which need overrides, and others to defaults.          }
  { This is called each time SetGraphMode() is called.     }
  {********************************************************}
  Begin
    { All default hooks procedures }

    { required...}
    DirectPutPixel := nil;
    PutPixel := nil;
    GetPixel := nil;
    SetRGBPalette := nil;
    GetRGBPalette := nil;

    { optional...}
{$ifdef fpc}
    SetActivePage := @SetActivePageDefault;
    SetVisualPage := @SetVisualPageDefault;
    ClearViewPort := @ClearViewportDefault;
    PutImage := @DefaultPutImage;
    GetImage := @DefaultGetImage;
    ImageSize := @DefaultImageSize;
{$else fpc}
    SetActivePage := SetActivePageDefault;
    SetVisualPage := SetVisualPageDefault;
    ClearViewPort := ClearViewportDefault;
    PutImage := DefaultPutImage;
    GetImage := DefaultGetImage;
    ImageSize := DefaultImageSize;
{$endif fpc}
    GraphFreeMemPtr := nil;
    GraphGetMemPtr := nil;
{$ifdef fpc}
    GetScanLine := @GetScanLineDefault;
    Line := @LineDefault;
    InternalEllipse := @InternalEllipseDefault;
    PatternLine := @PatternLineDefault;
    HLine := @HLineDefault;
    VLine := @VLineDefault;
{$else fpc}
    GetScanLine := GetScanLineDefault;
    Line := LineDefault;
    InternalEllipse := InternalEllipseDefault;
    PatternLine := PatternLineDefault;
    HLine := HLineDefault;
    VLine := VLineDefault;
{$endif fpc}
  end;

  Procedure InitVars;
  {********************************************************}
  { Procedure InitVars()                                   }
  {--------------------------------------------------------}
  { Resets all internal variables, and resets all          }
  { overridable routines.                                  }
  {********************************************************}
   Begin
    DirectVideo := TRUE;  { By default use fastest access possible }
    ArcCall.X := 0;
    ArcCall.Y := 0;
    ArcCall.XStart := 0;
    ArcCall.YStart := 0;
    ArcCall.XEnd := 0;
    ArcCall.YEnd := 0;
    { Reset to default values }
    IntCurrentMode := 0;
    IntCurrentDriver := 0;
    XAspect := 0;
    YAspect := 0;
    MaxX := 0;
    MaxY := 0;
    MaxColor := 0;
    PaletteSize := 0;
    DirectColor := FALSE;
    HardwarePages := 0;
    DefaultHooks;
  end;




{$i modes.inc}
{$i graph.inc}


  function InstallUserDriver(Name: string; AutoDetectPtr: Pointer): integer;
   begin
     _graphResult := grError;
   end;

  function RegisterBGIDriver(driver: pointer): integer;

   begin
     _graphResult := grError;
   end;



{ ----------------------------------------------------------------- }



  Procedure Arc(X,Y : Integer; StAngle,EndAngle,Radius: word);

   var
    OldWriteMode: word;

   Begin
     if (Radius = 0) then
           Exit;

     if (Radius = 1) then
       begin
         { must use clipping ... }
         { don't need to explicitly set NormalPut mode }
         { because PutPixel only supports normal put   }
             PutPixel(X, Y,CurrentColor);
             Exit;
       end;

     { Only if we are using thickwidths lines do we accept }
     { XORput write modes.                                 }
     OldWriteMode := CurrentWriteMode;
     if (LineInfo.Thickness = NormWidth) then
       CurrentWriteMode := NormalPut;
         InternalEllipse(X,Y,Radius,Radius,StAngle,Endangle);
     CurrentWriteMode := OldWriteMode;
   end;


 procedure Ellipse(X,Y : Integer; stAngle, EndAngle: word; XRadius,YRadius: word);
  Begin
    InternalEllipse(X,Y,XRadius,YRadius,stAngle,EndAngle);
  end;


 procedure FillEllipse(X, Y: Integer; XRadius, YRadius: Word);
  {********************************************************}
  { Procedure FillEllipse()                                }
  {--------------------------------------------------------}
  { Draws a filled ellipse using (X,Y) as a center point   }
  { and XRadius and YRadius as the horizontal and vertical }
  { axes. The ellipse is filled with the current fill color}
  { and fill style, and is bordered with the current color.}
  {--------------------------------------------------------}
  { Important notes:                                       }
  {  - CONTRRARY to VGA BGI - SetWriteMode DOES not        }
  {    affect the contour of the ellipses. BGI mode        }
  {    supports XORPut but the FloodFill() is still bounded}
  {    by the ellipse. In OUR case, XOR Mode is simply     }
  {    not supported.                                      }
  {********************************************************}
  var
   OldWriteMode: Word;
  begin
    { only normal put supported }
    OldWriteMode := CurrentWriteMode;
    CurrentWriteMode := NormalPut;
    InternalEllipse(X,Y,XRadius,YRadius,0,360);
    if (XRadius > 0) and (YRadius > 0) then
      FloodFill(X,Y,CurrentColor);
    { restore old write mode }
    CurrentWriteMode := OldWriteMode;
  end;



 procedure Circle(X, Y: Integer; Radius:Word);
  {********************************************************}
  { Draws a circle centered at X,Y with the given Radius.  }
  {********************************************************}
  { Important notes:                                       }
  {  - Thickwidth circles use the current write mode, while}
  {    normal width circles ALWAYS use CopyPut/NormalPut   }
  {    mode. (Tested against VGA BGI driver -CEC 13/Aug/99 }
  {********************************************************}
  var OriginalArcInfo: ArcCoordsType;
      OldWriteMode: word;

  begin
     if (Radius = 0) then
          Exit;

     if (Radius = 1) then
     begin
      { only normal put mode is supported by a call to PutPixel }
          PutPixel(X, Y, CurrentColor);
          Exit;
     end;

     { save state of arc information }
     { because it is not needed for  }
     { a circle call.                }
     move(ArcCall,OriginalArcInfo, sizeof(ArcCall));
     if LineInfo.Thickness = Normwidth then
       begin
             OldWriteMode := CurrentWriteMode;
             CurrentWriteMode := CopyPut;
       end;
     InternalEllipse(X,Y,Radius,Radius,0,360);
     if LineInfo.Thickness = Normwidth then
         CurrentWriteMode := OldWriteMode;
     { restore arc information }
     move(OriginalArcInfo, ArcCall,sizeof(ArcCall));
 end;



 procedure Sector(x, y: Integer; StAngle,EndAngle, XRadius, YRadius: Word);
  var angle : real;
      writemode : word;
  begin
     Ellipse(x,y,stAngle,endAngle,XRadius,YRadius);
    { As in the TP graph unit - the line settings are used to }
    { define the outline of the sector.                       }
     writemode:=Currentwritemode;
     Currentwritemode:=normalput;
     Line(ArcCall.XStart, ArcCall.YStart, x,y);
     Line(x,y,ArcCall.Xend,ArcCall.YEnd);
     { we must take care of clipping so we call PutPixel instead }
     { of DirectPutPixel...                                      }
     PutPixel(ArcCall.xstart,ArcCall.ystart,CurrentColor);
     PutPixel(x,y,CurrentColor);
     PutPixel(ArcCall.xend,ArcCall.yend,CurrentColor);
     stangle:=Stangle mod 360; EndAngle:=Endangle mod 360;
     if stAngle<=Endangle then
       Angle:=(stAngle+EndAngle)/2
     else
       angle:=(stAngle-360+EndAngle)/2;
     { fill from the point in the middle of the slice }
     XRadius:=(longint(XRadius)*10000) div XAspect;
     YRadius:=(longint(YRadius)*10000) div YAspect;
     { avoid rounding errors }
     if abs(ArcCall.xstart-ArcCall.xend)
        +abs(ArcCall.ystart-ArcCall.yend)>2 then
       FloodFill(x+round(sin((angle+90)*Pi/180)*XRadius/2),
         y+round(cos((angle+90)*Pi/180)*YRadius/2),CurrentColor);
     CurrentWriteMode := writemode;
  end;



   procedure SetFillStyle(Pattern : word; Color: word);

   begin
     { on invalid input, the current fill setting will be }
     { unchanged.                                         }
     if (Pattern > UserFill) or (Color > GetMaxColor) then
      begin
           _GraphResult := grError;
           exit;
      end;
     FillSettings.Color := Color;
     FillSettings.Pattern := Pattern;
   end;


  procedure SetFillPattern(Pattern: FillPatternType; Color: word);
  {********************************************************}
  { Changes the Current FillPattern to a user defined      }
  { pattern and changes also the current fill color.       }
  { The FillPattern is saved in the FillPattern array so   }
  { it can still be used with SetFillStyle(UserFill,Color) }
  {********************************************************}
   var
    i: integer;

   begin
     if Color > GetMaxColor then
       begin
            _GraphResult := grError;
            exit;
       end;

     FillSettings.Color := Color;
     FillSettings.Pattern := UserFill;

     { Save the pattern in the buffer }
     For i:=1 to 8 do
       FillPatternTable[UserFill][i] := Pattern[i];

   end;

  procedure Bar(x1,y1,x2,y2:integer);
  {********************************************************}
  { Important notes for compatibility with BP:             }
  {     - WriteMode is always CopyPut                      }
  {     - No contour is drawn for the lines                }
  {********************************************************}
  var y               : Integer;
      origcolor       : longint;
      origlinesettings: Linesettingstype;
      origwritemode   : Integer;
   begin
     origlinesettings:=lineinfo;
     origcolor:=CurrentColor;
     if y1>y2 then
       begin
          y:=y1;
          y1:=y2;
          y2:=y;
       end;

     { Always copy mode for Bars }
     origwritemode := CurrentWriteMode;
     CurrentWriteMode := CopyPut;

     { All lines used are of this style }
     Lineinfo.linestyle:=solidln;
     Lineinfo.thickness:=normwidth;

     case Fillsettings.pattern of
     EmptyFill :
           begin
                     Currentcolor:=CurrentBkColor;
                     for y:=y1 to y2 do
                       Hline(x1,x2,y);
                   end;
     SolidFill :
           begin
                     CurrentColor:=FillSettings.color;
                     for y:=y1 to y2 do
                       Hline(x1,x2,y);
                  end;
     else
      Begin
            CurrentColor:=FillSettings.color;
        for y:=y1 to y2 do
                  patternline(x1,x2,y);
      end;
    end;
    CurrentColor:= Origcolor;
    LineInfo := OrigLineSettings;
    CurrentWriteMode := OrigWritemode;
   end;




procedure bar3D(x1, y1, x2, y2 : integer;depth : word;top : boolean);
var
 origwritemode : integer;
 OldX, OldY : integer;
begin
  origwritemode := CurrentWriteMode;
  CurrentWriteMode := CopyPut;
  Bar(x1,y1,x2,y2);
  Rectangle(x1,y1,x2,y2);

  { Current CP should not be updated in Bar3D }
  { therefore save it and then restore it on  }
  { exit.                                     }
  OldX := CurrentX;
  OldY := CurrentY;

  if top then begin
    Moveto(x1,y1);
    Lineto(x1+depth,y1-depth);
    Lineto(x2+depth,y1-depth);
    Lineto(x2,y1);
  end;
  if Depth <> 0 then
    Begin
      Moveto(x2+depth,y1-depth);
      Lineto(x2+depth,y2-depth);
      Lineto(x2,y2);
    end;
  { restore CP }
  CurrentX := OldX;
  CurrentY := OldY;
  CurrentWriteMode := origwritemode;
end;



{--------------------------------------------------------------------------}
{                                                                          }
{                       COLOR AND PALETTE ROUTINES                         }
{                                                                          }
{--------------------------------------------------------------------------}


  {$i palette.inc}

  procedure SetColor(Color: Word);

   Begin
     CurrentColor := Color;
   end;


  function GetColor: Word;

   Begin
     GetColor := CurrentColor;
   end;

  function GetBkColor: Word;

   Begin
     GetBkColor := CurrentBkColor;
   end;


  procedure SetBkColor(ColorNum: Word);
  { Background color means background screen color in this case, and it is  }
  { INDEPENDANT of the viewport settings, so we must clear the whole screen }
  { with the color.                                                         }
   var
     ViewPort: ViewportType;
   Begin
     GetViewSettings(Viewport);
     SetViewPort(0,0,MaxX,MaxY,FALSE);
     CurrentBkColor := ColorNum;
     ClearViewPort;
     SetViewport(ViewPort.X1,Viewport.Y1,Viewport.X2,Viewport.Y2,Viewport.Clip);
   end;


  function GetMaxColor: word;
  { Checked against TP VGA driver - CEC }

   begin
      GetMaxColor:=MaxColor-1; { based on an index of zero so subtract one }
   end;






   Procedure MoveRel(Dx, Dy: Integer);
    Begin
     CurrentX := CurrentX + Dx;
     CurrentY := CurrentY + Dy;
   end;

   Procedure MoveTo(X,Y: Integer);
  {********************************************************}
  { Procedure MoveTo()                                     }
  {--------------------------------------------------------}
  { Moves the current pointer in VIEWPORT relative         }
  { coordinates to the specified X,Y coordinate.           }
  {********************************************************}
    Begin
     CurrentX := X;
     CurrentY := Y;
    end;


function GraphErrorMsg(ErrorCode: Integer): string;
Begin
 GraphErrorMsg:='';
 case ErrorCode of
  grOk,grFileNotFound,grInvalidDriver: exit;
  grNoInitGraph: GraphErrorMsg:='Graphics driver not installed';
  grNotDetected: GraphErrorMsg:='Graphics hardware not detected';
  grNoLoadMem,grNoScanMem,grNoFloodMem: GraphErrorMsg := 'Not enough memory for graphics';
  grNoFontMem: GraphErrorMsg := 'Not enough memory to load font';
  grFontNotFound: GraphErrorMsg:= 'Font file not found';
  grInvalidMode: GraphErrorMsg := 'Invalid graphics mode';
  grError: GraphErrorMsg:='Graphics error';
  grIoError: GraphErrorMsg:='Graphics I/O error';
  grInvalidFont,grInvalidFontNum: GraphErrorMsg := 'Invalid font';
  grInvalidVersion: GraphErrorMsg:='Invalid driver version';
 end;
end;




  Function GetMaxX: Integer;
  { Routine checked against VGA driver - CEC }
   Begin
     GetMaxX := MaxX;
   end;

  Function GetMaxY: Integer;
  { Routine checked against VGA driver - CEC }
   Begin
    GetMaxY := MaxY;
   end;




Function GraphResult: Integer;
Begin
  GraphResult := _GraphResult;
  _GraphResult := grOk;
end;


  Function GetX: Integer;
   Begin
     GetX := CurrentX;
   end;


  Function GetY: Integer;
   Begin
     GetY := CurrentY;
   end;

   Function GetDriverName: string;
    var
     mode: PModeInfo;
    begin
      GetDriverName:=DriverName;
    end;


   procedure graphdefaults;
   { PS: GraphDefaults does not ZERO the ArcCall structure }
   { so a call to GetArcCoords will not change even the    }
   { returned values even if GraphDefaults is called in    }
   { between.                                              }
    var
     i: integer;
   begin
         lineinfo.linestyle:=solidln;
         lineinfo.thickness:=normwidth;
         { reset line style pattern }
         for i:=0 to 15 do
           LinePatterns[i] := TRUE;

         { By default, according to the TP prog's reference }
         { the default pattern is solid, and the default    }
         { color is the maximum color in the palette.       }
         fillsettings.color:=GetMaxColor;
         fillsettings.pattern:=solidfill;
         { GraphDefaults resets the User Fill pattern to $ff }
         { checked with VGA BGI driver - CEC                 }
         for i:=1 to 8 do
           FillPatternTable[UserFill][i] := $ff;


         CurrentColor:=white;
         SetBkColor(Black);


         ClipPixels := TRUE;
         { Reset the viewport }
         StartXViewPort := 0;
         StartYViewPort := 0;
         ViewWidth := MaxX;
         ViewHeight := MaxY;
         { Reset CP }
         CurrentX := 0;
         CurrentY := 0;

         { normal write mode }
         CurrentWriteMode := CopyPut;

         { Schriftart einstellen }
         CurrentTextInfo.font := DefaultFont;
         CurrentTextInfo.direction:=HorizDir;
         CurrentTextInfo.charsize:=1;
         CurrentTextInfo.horiz:=LeftText;
         CurrentTextInfo.vert:=TopText;

         XAspect:=10000; YAspect:=10000;
   end;


    procedure GetAspectRatio(var Xasp,Yasp : word);
    begin
      XAsp:=XAspect;
      YAsp:=YAspect;
    end;

  procedure SetAspectRatio(Xasp, Yasp : word);
  begin
    Xaspect:= XAsp;
    YAspect:= YAsp;
  end;


  procedure SetWriteMode(WriteMode : integer);
   begin
     if (writemode<>xorput) and (writemode<>CopyPut) then
            exit;
     CurrentWriteMode := WriteMode;
   end;


  procedure GetFillSettings(var Fillinfo:Fillsettingstype);
   begin
     Fillinfo:=Fillsettings;
   end;

  procedure GetFillPattern(var FillPattern:FillPatternType);
   begin
     FillPattern:=FillpatternTable[UserFill];
   end;






  procedure DrawPoly(numpoints : word;var polypoints);

      type
            ppointtype = ^pointtype;
        pt = array[0..16000] of pointtype;

      var
            i : longint;

    begin
         if numpoints < 2 then
           begin
             _GraphResult := grError;
             exit;
           end;
         for i:=0 to numpoints-2 do
           line(pt(polypoints)[i].x,
                pt(polypoints)[i].y,
                pt(polypoints)[i+1].x,
                pt(polypoints)[i+1].y);
    end;


  procedure PieSlice(X,Y,stangle,endAngle:integer;Radius: Word);
  var angle : real;
      XRadius, YRadius : word;
      writemode : word;
  begin
     Arc(x,y,StAngle,EndAngle,Radius);
     Line(ArcCall.XStart, ArcCall.YStart, x,y);
     Line(x,y, ArcCall.XEnd, ArcCall.YEnd);
     { must use PutPixel() instead of DirectPutPixel because we need }
     { clipping...                                                   }
     PutPixel(ArcCall.xstart,ArcCall.ystart,CurrentColor);
     PutPixel(x,y,CurrentColor);
     PutPixel(ArcCall.xend,ArcCall.yend,CurrentColor);
     Stangle:=stAngle mod 360; EndAngle:=Endangle mod 360;
     if Stangle<=Endangle then
       angle:=(StAngle+EndAngle)/2
     else
       angle:=(Stangle-360+Endangle)/2;
     { fill from the point in the middle of the slice }
     XRadius:=(longint(Radius)*10000) div XAspect;
     YRadius:=(longint(Radius)*10000) div YAspect;
     { avoid rounding errors }
     if abs(ArcCall.xstart-ArcCall.xend)
        +abs(ArcCall.ystart-ArcCall.yend)>2 then
{       FloodFill(x+round(sin((angle+90)*Pi/180)*XRadius/2),
         y+round(cos((angle+90)*Pi/180)*YRadius/2),truecolor);}
{     CurrentWriteMode := writemode;}
  end;

{$i fills.inc}
{$i text.inc}


  procedure InitGraph(var GraphDriver:Integer;var GraphMode:Integer;
    const PathToDriver:String);
  var i,index:Integer;
     LoMode, HiMode: Integer;
     CpyMode: Integer;
     CpyDriver: Integer;
  begin
    { path to the fonts (where they will be searched)...}
    bgipath:=PathToDriver;
    if bgipath[length(bgipath)]<>'\' then
    bgipath:=bgipath+'\';

    { make sure our driver list is setup...}
    QueryAdapterInfo;
    if not assigned(SaveVideoState) then
      RunError(216);
    SaveVideoState;
    InitVars;
    DriverName:=InternalDriverName;   { DOS Graphics driver }

    if (Graphdriver=Detect) then
      begin
          HiMode := -1;
          LoMode := -1;
          { We start at VGA-1 }
          GraphDriver := VGA;
          CpyMode := 0;
          { search all possible graphic drivers in ascending order...}
          { usually the new driver numbers indicate newest hardware...}
          { Internal driver numbers start at VGA=9 }
          repeat
             GetModeRange(GraphDriver,LoMode,HiMode);
             { save the highest mode possible...}
             if HiMode = -1 then break;
             CpyMode:=HiMode;
             CpyDriver:=GraphDriver;
             { go to next driver if it exists...}
             Inc(GraphDriver);
          until (CpyMode=-1);
        IntCurrentDriver := CpyDriver;
        { If this is equal to -1 then no graph mode possible...}
        if CpyMode = -1 then
         begin
           _GraphResult := grNotDetected;
           exit;
         end;
        { Actually set the graph mode...}
        SetGraphMode(CpyMode);
      end
    else
      begin
        { Search if that graphics modec actually exists...}
        if SearchMode(GraphDriver,GraphMode) = nil then
          begin
            _GraphResult := grInvalidMode;
            exit;
         end
        else
         begin
           IntCurrentDriver := GraphDriver;
           SetGraphMode(GraphMode);
         end;
      end;
  end;


 procedure SetDirectVideo(DirectAccess: boolean);
  begin
    DirectVideo := DirectAccess;
  end;

 function GetDirectVideo: boolean;
  begin
    GetDirectVideo := DirectVideo;
  end;



var
 ExitSave: pointer;

begin
{$ifdef logging}
 assign(debuglog,'grlog.txt');
 rewrite(debuglog);
 close(debuglog);
{$endif logging}
 ModeList := nil;
 SaveVideoState := nil;
 RestoreVideoState := nil;
 SavePtr := Nil;
 { This must be called at startup... because GetGraphMode may }
 { be called even when not in graph mode.                     }
{$ifdef logging}
 LogLn('Calling QueryAdapterInfo...');
{$endif logging}
 QueryAdapterInfo;
 { Install standard fonts }
 { This is done BEFORE startup... }
 InstalledFonts := 0;
 InstallUserFont('TRIP');
 InstallUserFont('LITT');
 InstallUserFont('SANS');
 InstallUserFont('GOTH');
 { This installs an exit procedure which cleans up the mode list...}
 ExitSave := ExitProc;
 ExitProc := @CleanMode;
end.


PieSlice
Sector
SetGraphBufSize
SetBkColor
DetectGraph

{   DetectGraph()                                       }
{   SetBkColor()                                        }

{
  $Log$
  Revision 1.19  1999-09-11 19:43:01  jonas
    * FloodFill: did not take into account current viewport settings
    * GetScanLine: only get line inside viewport, data outside of it
      is not used anyway
    * InternalEllipseDefault: fix for when xradius or yradius = 0 and
      increase xradius and yradius always by one (TP does this too)
    * fixed conlict in vesa.inc from last update
    * some conditionals to avoid range check and overflow errors in
      places where it doesn't matter

  Revision 1.18  1999/07/26 09:38:41  florian
    * bar: y2 can be less y1, fixed
    * settextstyle: charsize can be 0, must be changed into 1

  Revision 1.17  1999/07/18 15:07:20  jonas
    + xor-, and and- orput support for VESA256 modes
    * compile with -dlogging if you wnt some info to be logged to grlog.txt

  Revision 1.16  1999/07/14 18:18:04  florian
    * cosmetic changes

}