GDI+ 学习记录(21) 颜色

//颜色透明度
var
  g: TGPGraphics;
  sb: TGPSolidBrush;
begin
  g := TGPGraphics.Create(Canvas.Handle);

  sb := TGPSolidBrush.Create(MakeColor(128,255,0,0)); {128表示半透明}

  g.FillRectangle(sb,10,10,100,100);
  sb.Free;
  g.Free;
end;

//使用 GDI+ 的颜色类型
var
  g: TGPGraphics;
  sb: TGPSolidBrush;
  color: TGPColor; {其实颜色是 DWORD 类型的}
begin
  g := TGPGraphics.Create(Canvas.Handle);

  color := aclRed;

  sb := TGPSolidBrush.Create(color);
  g.FillRectangle(sb,10,10,100,100);

  sb.Free;
  g.Free;
end;

 

//颜色混合模式
var
  g:TGPGraphics;
  p:TGPPen;
begin
  g:=TGPGraphics.Create(Canvas.Handle);
  //g.Clear(aclBlue); //如果底色设为蓝色，那么我们就能看到混合时会很明显
  p:=TGPPen.Create(MakeColor(128,255,0,0),20);

  g.SetCompositingMode(CompositingModeSourceCopy);   //{改写背景色}
  g.DrawLine(p,11,11,111,111);
  g.SetCompositingMode(CompositingModeSourceOver);  //{混合背景色, 默认值}
  g.DrawLine(p,66,11,222,128);

  p.Free;
  g.Free;
end;