The following example creates a linear gradient brush, sets a custom blend, and uses the brush to fill a rectangle.
C++
VOID Example_SetBlend(HDC hdc)
{
Graphics myGraphics(hdc);
REAL factors[4] = {0.0f, 0.4f, 0.6f, 1.0f};
REAL positions[4] = {0.0f, 0.2f, 0.8f, 1.0f};
Rect rect(0, 0, 100, 50);
LinearGradientBrush linGrBrush(
rect,
Color(255, 255, 0, 0), // red
Color(255, 0, 0, 255), // blue
LinearGradientModeHorizontal);
linGrBrush.SetBlend(factors, positions, 4);
myGraphics.FillRectangle(&linGrBrush, rect);
}
SUB GDIP_SetLineBlend (BYVAL hdc AS DWORD)
LOCAL hStatus AS LONG
LOCAL pGraphics AS DWORD
LOCAL rc AS RECTF
LOCAL colorRed AS DWORD
LOCAL colorBlue AS DWORD
LOCAL pLinBrush AS DWORD
DIM factors(3) AS SINGLE
DIM positions(3) AS SINGLE
hStatus = GdipCreateFromHDC(hdc, pGraphics)
rc.x = 0 : rc.y = 0 : rc.Width = 100 : rc.Height = 50
colorRed = GDIP_ARGB(255, 255, 0, 0)
colorBlue = GDIP_ARGB(255, 0, 0, 255)
factors(0) = 0.0! : factors(1) = 0.4! : factors(2) = 0.6! : factors(3) = 1.0!
positions(0) = 0.0! : positions(1) = 0.2! : positions(2) = 0.8! : positions(3) = 1.0!
hStatus = GdipCreateLineBrushFromRect(rc, colorRed, colorBlue, %LinearGradientModeHorizontal, %WrapModeTile, pLinBrush)
hStatus = GdipSetLineBlend(pLinBrush, factors(0), positions(0), 4)
hStatus = GdipFillRectangle(pGraphics, pLinBrush, rc.x, rc.y, rc.Width, rc.Height)
' // Cleanup
IF pLinBrush THEN GdipDeleteBrush(pLinBrush)
IF pGraphics THEN GdipDeleteGraphics(pGraphics)
END SUB
(http://www.jose.it-berater.org/captures/GdipSetLineBlend.png)