GDI+: GdipSetImageAttributesRemapTable

[José Roca]

The following example creates an Image object based on a .bmp file and then draws the image. The code creates an ImageAttributes object and sets its default remap table so that red is converted to blue. Then the code draws the image again using the color adjustment specified by the remap table.

C++

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VOID Example_SetRemapTable(HDC hdc)
{
   Graphics graphics(hdc);

   // Create an Image object based on a .bmp file.
   // The image has one red stripe and one green stripe.
   Image image(L"RedGreenStripes.bmp");

   // Create an ImageAttributes object and set its remap table.
   ImageAttributes imageAtt;
   ColorMap cMap;
   cMap.oldColor = Color(255, 255, 0, 0);  // red
   cMap.newColor = Color(255, 0, 0, 255);  // blue
   imageAtt.SetRemapTable(12, &cMap,
      ColorAdjustTypeDefault);

   // Draw the image with no color adjustment.
   graphics.DrawImage(&image, 10, 10, image.GetWidth(), image.GetHeight());

   // Draw the image with red converted to blue.
   graphics.DrawImage(&image,
      Rect(100, 10, image.GetWidth(), image.GetHeight()),  // dest rect
      0, 0, image.GetWidth(), image.GetHeight(),           // source rect
      UnitPixel,
      &imageAtt);
}


PowerBASIC

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SUB GDIP_SetRemapTable (BYVAL hdc AS DWORD)

   LOCAL hStatus AS LONG
   LOCAL pGraphics AS DWORD
   LOCAL pImage AS DWORD
   LOCAL pImgAttr AS DWORD
   LOCAL strFileName AS STRING
   LOCAL cMap AS GDIP_ColorMap
   LOCAL nWidth AS DWORD
   LOCAL nHeight AS DWORD

   hStatus = GdipCreateFromHDC(hdc, pGraphics)

   ' // Create an Image object based on a .bmp file.
   ' // The image has one red stripe and one green stripe.
   strFileName = UCODE$("RedGreenStripes.bmp")
   hStatus = GdipLoadImageFromFile(STRPTR(strFileName), pImage)

   ' // Create an ImageAttributes object and set its remap table.
   cMap.oldColor = GDIP_ARGB(255, 255, 0, 0)  ' // red
   cMap.newColor = GDIP_ARGB(255, 0, 0, 255)  ' // blue
   hStatus = GdipCreateImageAttributes(pImgAttr)
   hStatus = GdipSetImageAttributesRemapTable(pImgAttr, %ColorAdjustTypeDefault, %TRUE, 1, cMap)

   ' // Draw the image with no color adjustment.
   hStatus = GdipGetImageWidth(pImage, nWidth)
   hStatus = GdipGetImageHeight(pImage, nHeight)
   hStatus = GdipDrawImageRectI(pGraphics, pImage, 10, 10, nWidth, nHeight)

   ' // Draw the image with red converted to blue.
   hStatus = GdipDrawImageRectRectI(pGraphics, pImage, _
             100, 10, nWidth, nHeight, _       ' // dest rect
             0, 0, nWidth, nHeight, _          ' // source rect
             %UnitPixel, pImgAttr, %NULL, %NULL)

   ' // Cleanup
   IF pImgAttr THEN GdipDisposeImageAttributes(pImgAttr)
   IF pImage THEN GdipDisposeImage(pImage)
   IF pGraphics THEN GdipDeleteGraphics(pGraphics)

END SUB


The following illustration shows the output of the preceding code.