GDI+: GdipSetLineTransform

[José Roca]

The following example creates a linear gradient brush and uses it to fill a rectangle. Next, the code modifies the brush's transformation matrix and fills a rectangle with the transformed brush.

C++

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VOID Example_SetTransform(HDC hdc)
{
   Graphics myGraphics(hdc);

   LinearGradientBrush linGrBrush(
      Rect(0, 0, 100, 50),
      Color(255, 255, 0, 0),  // red
      Color(255, 0, 0, 255),  // blue
      LinearGradientModeHorizontal);

   Matrix matrix(2.0, 0, 0, 1, 0, 0);  // horizontal doubling

   // Fill a large area with the linear gradient brush (no transformation).
   myGraphics.FillRectangle(&linGrBrush, 0, 0, 800, 50);

   linGrBrush.SetTransform(&matrix);

   // Fill a large area with the transformed linear gradient brush.
   myGraphics.FillRectangle(&linGrBrush, 0, 75, 800, 50);
}


PowerBASIC

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SUB GDIP_SetLineTransform (BYVAL hdc AS DWORD)

   LOCAL hStatus AS LONG
   LOCAL pGraphics AS DWORD
   LOCAL pLinBrush AS DWORD
   LOCAL pMatrix AS DWORD
   LOCAL rc AS RECTF
   LOCAL colorRed AS DWORD
   LOCAL colorBlue AS DWORD

   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)
   hStatus = GdipCreateLineBrushFromRect(rc, colorRed, colorBlue, %LinearGradientModeHorizontal, %WrapModeTile, pLinBrush)

   hStatus = GdipCreateMatrix2(2, 0, 0, 1, 0, 0, pMatrix)   ' // horizontal doubling

   ' // Fill a large area with the linear gradient brush (no transformation).
   hStatus = GdipFillRectangle(pGraphics, pLinBrush, 0, 0, 800, 50)

   hStatus = GdipSetLineTransform(pLinBrush, pMatrix)

   ' // Fill a large area with the transformed linear gradient brush.
   hStatus = GdipFillRectangle(pGraphics, pLinBrush, 0, 75, 800, 50)

   ' // Cleanup
   IF pMatrix THEN GdipDeleteMatrix(pMatrix)
   IF pLinBrush THEN GdipDeleteBrush(pLinBrush)
   IF pGraphics THEN GdipDeleteGraphics(pGraphics)

END SUB