The following example creates a
Bitmap based on a JPEG file. The code draws the bitmap once unaltered. Then the code calls the
GdipBitmapSetPixel function to create a checkered pattern of black pixels in the bitmap and draws the altered bitmap.
C++
VOID Example_SetPixel(HDC hdc)
{
Graphics graphics(hdc);
// Create a Bitmap object from a JPEG file.
Bitmap myBitmap(L"Climber.jpg");
// Draw the bitmap.
graphics.DrawImage(&myBitmap, 0, 0);
// Create a checkered pattern with black pixels.
for (UINT row = 0; row < myBitmap.GetWidth(); row += 2)
{
for (UINT col = 0; col < myBitmap.GetHeight(); col += 2)
{
myBitmap.SetPixel(row, col, Color(255, 0, 0, 0));
}
}
// Draw the altered bitmap.
graphics.DrawImage(&myBitmap, 200, 0);
}
SUB GDIP_SetPixel (BYVAL hdc AS DWORD)
LOCAL hStatus AS LONG
LOCAL pGraphics AS DWORD
LOCAL pBitmap AS DWORD
LOCAL strFileName AS STRING
LOCAL pixelColor AS DWORD
LOCAL nWidth AS DWORD
LOCAL nHeight AS DWORD
LOCAL row AS LONG
LOCAL col AS LONG
hStatus = GdipCreateFromHDC(hdc, pGraphics)
' // Create a Bitmap object from a JPEG file.
strFileName = UCODE$("climber.jpg")
hStatus = GdipCreateBitmapFromFile(STRPTR(strFileName), pBitmap)
' // Draw the bitmap
hStatus = GdipDrawImageI(pGraphics, pBitmap, 0, 0)
' // Get the width and height of the bitmap
hStatus = GdipGetImageWidth(pBitmap, nWidth)
hStatus = GdipGetImageHeight(pBitmap, nHeight)
' // Make an ARGB color
pixelColor = GDIP_ARGB(255, 0, 0, 0)
' // Create a checkered pattern with black pixels.
FOR row = 0 TO nWidth - 1 STEP 2
FOR col = 0 TO nHeight STEP 2
hStatus = GdipBitmapSetPixel(pBitmap, row, col, pixelColor)
NEXT
NEXT
' // Draw the altered bitmap.
hStatus = GdipDrawImageI(pGraphics, pBitmap, 200, 0)
' // Cleanup
IF pBitmap THEN GdipDisposeImage(pBitmap)
IF pGraphics THEN GdipDeleteGraphics(pGraphics)
END SUB
(http://www.jose.it-berater.org/captures/GdipBitmapSetPixel.png)