galfar.imaginglib/Doc/VampyreDoc/Procedures/Low/Manipulating.xml

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<doc>
  <title>Manipulating Images</title>
  <chapter>
    <title>Manipulating Images</title>
    <par>Imaging offers some image manipulation functions which work
    with all supported image data formats. Conversions, resizing,
    color reduction and other are available.
    You can find list of all low level image manipulation and drawing/pixel
    functions in <link url="../../Usage/LowLevel.xml">Low Level Interface</link> section.
    You can look at usage of many of these functions in the
    <link url="../../Demos/Pascal.xml#vampconvert">VampConvert</link>
    and
    <link url="../../Demos/Pascal.xml#benchmark">Benchmark</link> Object Pascal demos
    and <link url="../../Demos/Cpp.xml#benchmark">C++ Benchmark</link> demo.</par>

    <par>In the following code listing you can see typical usage of Imaging's
    manipulation functions.</par>

    <code>
uses
  ImagingTypes, Imaging;
var
  Img, ImgClone: <ref>TImageData</ref>;
begin
  ...
  // image is now initialized and loaded
  // now we want image to be mirrored
  <ref>MirrorImage</ref>(Img);
  // and flipped
  <ref>FlipImage</ref>(Img);
  // conversion to 32bit ARGB format
  <ref>ConvertImage</ref>(Img, ifA8R8G8B8);
  // swap alpha channel with green channel
  <ref>SwapChannels</ref>(Img, ChannelAlpha, ChannelGreen);
  // now we make clone of image
  <ref>InitImage</ref>(ImgClone);
  <ref>CloneImage</ref>(Img, ImgClone);
  // reduce colors of clone to 1024
  <ref>ReduceColors</ref>(ImgClone, 1024);
  // and resize original image
  <ref>ResizeImage</ref>(Img, Img.Width * 2, Image.Height div 2, rfBicubic);
  // finally convert clone to DXT5
  <ref>ConvertImage</ref>(ImgClone, ifDXT5);
  // do something else with image
  ...
end.
    </code>
    
    <par>In this example you can find how to pass fill color parameters to 
    functions like <ref>FillRect</ref>. These functions work for all possible image 
    data format so fill color is defined as pointer to pixel in image's format.
    You can also use <ref>GetPixel32</ref>, <ref>SetPixel32</ref>,
    <ref>GetPixelFP</ref>, and <ref>SetPixelFP</ref> to set/get pixel colors
    which are automatically converted to native color format of each data format.

    </par>

    <code>
var
  Img: <ref>TImageData</ref>;
  Pix32: <ref>TColor32Rec</ref>
  Pix24: <ref>TColor24Rec</ref>
  Pix64: <ref>TColor64Rec</ref>
  Pix48: <ref>TColor48Rec</ref>
  PixWord: Word;
  PixByte: Byte;
begin
  ...
  // image is now initialized and loaded
  // now we set pixel colors 
  Pix32.Color := $FFFF0000; // opaque red
  Pix64.Color := $FFFF0000FFFF0000; // opaque green 
  with Pix24 do begin R := $FF; G := $FF; B := 0; end; // yellow 
  with Pix48 do begin R := $FF00; G := $00FF; B := $0800; end; // something redish
  PixWord := (31 shl 10) or (15 shl 5) or 25; // something violetish in R5G5B5
  PixByte := 111; 
 
  // image is then converted between various formats
  // and rectangle is filled with appropriate pixels
  
  <ref>ConvertImage</ref>(Img, ifA16R16G16B16);
  <ref>FillRect</ref>(Img, 20, 20, 60, 40, @Pix64);
  
  ConvertImage(Img, ifA8R8G8B8);
  FillRect(Img, 20, 20, 60, 40, @Pix32);
  
  ConvertImage(Img, ifR16G16B16);
  FillRect(Img, 20, 20, 60, 40, @Pix48);
  
  ConvertImage(Img, ifR8G8B8);
  FillRect(Img, 20, 20, 60, 40, @Pix24);
  
  ConvertImage(Img, ifX1R5G5B5);
  FillRect(Img, 20, 20, 60, 40, @PixWord);
  
  ConvertImage(Img, ifGray8);
  FillRect(Img, 20, 20, 60, 40, @PixByte);
 
  ...
end.    
    </code>
  

  </chapter>
</doc>