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

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<doc>
  <title>Saving Images</title>
  <chapter>
    <title>Saving Images</title>
    <par>Images can be saved to the files on disk, to the streams or
    to a memory referenced by a pointer.
    The following table lists functions which can be used for saving images.
    These are low level functions operating on <ref>TImageData</ref> structure.</par>
    <table>
      <row>
        <header>Function name</header>
        <header>Usage</header>
      </row>
      <row>
        <cell><ref>SaveImageToFile</ref></cell>
        <cell>Save single image to file</cell>
      </row>
      <row>
        <cell><ref>SaveImageToStream</ref></cell>
        <cell>Save single image to stream
        (<icode>TStream</icode> descendants, <b>Object Pascal only</b>)</cell>
      </row>
      <row>
        <cell><ref>SaveImageToMemory</ref></cell>
        <cell>Save single image to memory</cell>
      </row>
      <row>
        <cell><ref>SaveMultiImageToFile</ref></cell>
        <cell>Save multiple images to file</cell>
      </row>
      <row>
        <cell><ref>SaveMultiImageToStream</ref></cell>
        <cell>Save multiple images to stream
        (<icode>TStream</icode> descendants, <b>Object Pascal only</b>)</cell>
      </row>
      <row>
        <cell><ref>SaveMultiImageToMemory</ref></cell>
        <cell>Save multiple images to memory</cell>
      </row>
    </table>
    <par>You can learn how to use these functions from the
    following code fragments.</par>

    <par>This example creates empty image and draws diagonal line from
    left-top to right-bottom corner. Finally, image is saved to the file.</par>
    <code>
uses
  SysUtils, Classes, ImagingTypes, Imaging;
var
  Img: <ref>TImageData</ref>;
  I: LongInt;
begin
  // call this before using any TImageData record
  <ref>InitImage</ref>(Img);
  // create 8 bit grayscale image
  <ref>NewImage</ref>(1024, 1024, ifGray8, Img);
  // draw diagonal line by direct writing to image's memory
  for I := 0 to Img.Width - 1 do
    PByteArray(@PByteArray(Img.Bits)[I * Img.Width])[I] := 128;
  // save image to file
  <ref>SaveImageToFile</ref>('/home/galfar/images/line.tga', Img);
  // memory occupied by image is freed
  <ref>FreeImage</ref>(Img);
end.
    </code>

    <par>In this example DDS image is loaded from stream. All contained
    subimages are then compressed to DXT5 format and written to output stream.</par>
    <code>
procedure LoadAndSaveSomethingInDXT5(InStream, OutStream: TStream);
var
  Images: <ref>TDynImageDataArray</ref>;
  I: LongInt;
begin
  // load DDS multiimage from stream to Images array
  <ref>LoadMultiImageFromStream</ref>(InStream, Images);
  // convert all loaded images to DXT5 format
  for I := 0 to Length(Images) - 1 do
    <ref>ConvertImage</ref>(Images[I], ifDXT5);
  // save converted images to output stream in DDS format
  <ref>SaveMultiImageToStream</ref>('dds', OutStream, Images);
  // all images are freed
  <ref>FreeImagesInArray</ref>(Images);
end;
    </code>


  </chapter>
</doc>