TAgg2D.BlendMode(m)

Description

Changes the general rendering composition mode (compliant with SVG). This method applies only to the TBitmap surfaces with Alpha channel present (pf32bit).

Default composition mode is AGG_BlendAlpha, in which each pixel is rendered to the surface with the intensity of its Alpha Transparency value.

Parameters

m: TAggBlendMode [*]

A new general composition mode.

Example

if VG.Attach(Image1.Picture.Bitmap) then begin

  VG.ClearAll(255, 255, 255);

  // Draw basic blue rectangle
  VG.NoLine;
  VG.FillColor(0, 0, 255);
  VG.Rectangle(50, 50, 150, 150);

  // Rotate coordinates by 45 degrees
  VG.Translate(-ClientWidth / 2, -ClientHeight / 2);
  VG.Rotate(Deg2Rad(45));
  VG.Translate(ClientWidth / 2, ClientHeight / 2);

  // Changing the general composition mode
  VG.BlendMode(AGG_BlendContrast);

  // Draw the same blue rectangle but with red color
  // Result comes from applying composition mode
  VG.FillColor(255, 0, 0);
  VG.Rectangle(50, 50, 150, 150);

end;

More complex example:

Example download:
tagg2d_example08.zip
tagg2d_example08.exe