Drawing & Blending

Graphics32 supports high-speed line drawing, polygon fill, and alpha-blending primitives.

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Pixel Blending Modes

When drawing pixels onto a TBitmap32, Graphics32 supports several combine modes (TDrawMode):

• dmOpaque: Overwrites target pixel completely.
• dmBlend: Standard alpha blending using source pixel alpha channel.
• dmTransparent: Ignores pixels matching TransparentColor.
• dmCustom: Uses a user-assigned blending function callback.

Bitmap.DrawMode := dmBlend;

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Primitive Drawing Methods

Lines and Rectangles

// Antialiased line
Bitmap.LineA(X1, Y1, X2, Y2, clBlack32);

// Filled rectangle with alpha blending
Bitmap.FillRect(Left, Top, Right, Bottom, Color32(128, 255, 0, 0));

Vector Polygon Rasterization (GR32_Polygons)

uses GR32, GR32_Polygons;

procedure DrawPolygon(Bitmap: TBitmap32);
var
  Poly: TPolygon32;
begin
  Poly := TPolygon32.Create;
  try
    Poly.Add(PointD(100, 100));
    Poly.Add(PointD(200, 50));
    Poly.Add(PointD(250, 200));
    Poly.Add(PointD(150, 250));

    // Draw filled anti-aliased polygon
    Poly.DrawFill(Bitmap, clBlue32);
  finally
    Poly.Free;
  end;
end;