The following example creates a linear gradient brush, sets the colors to be interpolated for the linear gradient brush, and fills a rectangle.
C++
VOID Example_SetInterpColors(HDC hdc)
{
Graphics myGraphics(hdc);
Color colors[] = {
Color(255, 255, 0, 0), // red
Color(255, 0, 0, 255), // blue
Color(255, 0, 255, 0)}; // green
REAL positions[] = {
0.0f, // red at the left edge
0.3f, // blue at 30 percent of the distance from left edge
// to right edge
1.0f}; // green at the right edge
LinearGradientBrush linGrBrush(
Point(0, 0),
Point(100, 0),
Color(255, 0, 0, 0), // black
Color(255, 255, 255, 255)); // white
linGrBrush.SetInterpolationColors(colors, positions, 3);
myGraphics.FillRectangle(&linGrBrush, 0, 0, 100, 50);
}
SUB GDIP_SetLinePresetBlend (BYVAL hdc AS DWORD)
LOCAL hStatus AS LONG
LOCAL pGraphics AS DWORD
LOCAL pLinBrush AS DWORD
LOCAL colorBlack AS DWORD
LOCAL colorWhite AS DWORD
LOCAL pt1 AS POINTF
LOCAL pt2 AS POINTF
DIM blend(2) AS DWORD
DIM positions(2) AS SINGLE
hStatus = GdipCreateFromHDC(hdc, pGraphics)
blend(0) = GDIP_ARGB(255, 255, 0, 0) ' // red
blend(1) = GDIP_ARGB(255, 0, 0, 255) ' // blue
blend(2) = GDIP_ARGB(255, 0, 255, 0) ' // green
positions(0) = 0.0! ' // red at the left edge
positions(1) = 0.3! ' // blue at 30 percent of the distance from left edge to right edge
positions(2) = 1.0! ' // green at the right edge
pt1.x = 0 : pt1.y = 0 : pt2.x = 100 : pt2.y = 0
colorBlack = GDIP_ARGB(255, 0, 0, 0)
colorWhite = GDIP_ARGB(255, 255, 255, 255)
hStatus = GdipCreateLineBrush(pt1, pt2, colorBlack, colorWhite, %WrapModeTile, pLinBrush)
hStatus = GdipSetLinePresetBlend(pLinBrush, blend(0), positions(0), 3)
hStatus = GdipFillRectangle(pGraphics, pLinBrush, 0, 0, 100, 50)
' // Cleanup
IF pLinBrush THEN GdipDeleteBrush(pLinBrush)
IF pGraphics THEN GdipDeleteGraphics(pGraphics)
END SUB
(http://www.jose.it-berater.org/captures/GdipSetLinePresetBlend.png)