The following example creates an
Image object and calls the
GdipDrawImageRectI function to draw the image. Then the code creates an
ImageAttributes object and sets its bitmap output channel to cyan (
ColorChannelFlagsC). The code calls
GdipDrawImageRectI a second time, passing the address of the Image object and the address of the
ImageAttributes object. The cyan channel of each pixel is calculated, and the rendered image shows the intensities of the cyan channel as shades of gray. The code calls
GdipDrawImageRectI three more times to show the intensities of the magenta, yellow, and black channels.
C++
VOID Example_SetOutputChannel(HDC hdc)
{
Graphics graphics(hdc);
Image image(L"Mosaic2.bmp");
// Draw the image unaltered.
graphics.DrawImage(&image, 10, 10, width, height);
UINT width = image.GetWidth();
UINT height = image.GetHeight();
ImageAttributes imAtt;
// Draw the image, showing the intensity of the cyan channel.
imAtt.SetOutputChannel(ColorChannelFlagsC, ColorAdjustTypeBitmap);
graphics.DrawImage(
&image,
Rect(110, 10, width, height), // dest rect
0, 0, width, height, // source rect
UnitPixel,
&imAtt);
// Draw the image, showing the intensity of the magenta channel.
imAtt.SetOutputChannel(ColorChannelFlagsM, ColorAdjustTypeBitmap);
graphics.DrawImage(
&image,
Rect(210, 10, width, height), // dest rect
0, 0, width, height, // source rect
UnitPixel,
&imAtt);
// Draw the image, showing the intensity of the yellow channel.
imAtt.SetOutputChannel(ColorChannelFlagsY, ColorAdjustTypeBitmap);
graphics.DrawImage(
&image,
Rect(10, 110, width, height), // dest rect
0, 0, width, height, // source rect
UnitPixel,
&imAtt);
// Draw the image, showing the intensity of the black channel.
imAtt.SetOutputChannel(ColorChannelFlagsK, ColorAdjustTypeBitmap);
graphics.DrawImage(
&image,
Rect(110, 110, width, height), // dest rect
0, 0, width, height, // source rect
UnitPixel,
&imAtt);
}
SUB GDIP_SetImageAttributesOutputChannel (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 nWidth AS LONG
LOCAL nHeight AS LONG
hStatus = GdipCreateFromHDC(hdc, pGraphics)
' // Create an Image object based on a .bmp file.
strFileName = UCODE$("Mosaic2.bmp")
hStatus = GdipLoadImageFromFile(STRPTR(strFileName), pImage)
' // Draw the image unaltered.
hStatus = GdipGetImageWidth(pImage, nWidth)
hStatus = GdipGetImageHeight(pImage, nHeight)
hStatus = GdipDrawImageRectI(pGraphics, pImage, 10, 10, nWidth, nHeight)
' // Create an ImageAttributes object
hStatus = GdipCreateImageAttributes(pImgAttr)
' // Draw the image, showing the intensity of the cyan channel.
hStatus = GdipSetImageAttributesOutputChannel(pImgAttr, %ColorAdjustTypeBitmap, %TRUE, %ColorChannelFlagsC)
hStatus = GdipDrawImageRectRectI(pGraphics, pImage, _
110, 10, nWidth, nHeight, _ ' dest rect
0, 0, nWidth, nHeight, _ ' source dest
%UnitPixel, pImgAttr, %NULL, %NULL)
' // Draw the image, showing the intensity of the magenta channel.
hStatus = GdipSetImageAttributesOutputChannel(pImgAttr, %ColorAdjustTypeBitmap, %TRUE, %ColorChannelFlagsM)
hStatus = GdipDrawImageRectRectI(pGraphics, pImage, _
210, 10, nWidth, nHeight, _ ' dest rect
0, 0, nWidth, nHeight, _ ' source dest
%UnitPixel, pImgAttr, %NULL, %NULL)
' // Draw the image, showing the intensity of the yellow channel.
hStatus = GdipSetImageAttributesOutputChannel(pImgAttr, %ColorAdjustTypeBitmap, %TRUE, %ColorChannelFlagsY)
hStatus = GdipDrawImageRectRectI(pGraphics, pImage, _
10, 110, nWidth, nHeight, _ ' dest rect
0, 0, nWidth, nHeight, _ ' source dest
%UnitPixel, pImgAttr, %NULL, %NULL)
' // Draw the image, showing the intensity of the black channel.
hStatus = GdipSetImageAttributesOutputChannel(pImgAttr, %ColorAdjustTypeBitmap, %TRUE, %ColorChannelFlagsK)
hStatus = GdipDrawImageRectRectI(pGraphics, pImage, _
110, 110, nWidth, nHeight, _ ' dest rect
0, 0, nWidth, nHeight, _ ' source dest
%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.
(http://www.jose.it-berater.org/captures/GdipSetImageAttributesOutputChannel.png)