Delphi GDI+學習記錄(11): 路徑漸變畫刷 - PathGradientBrush(2)

//設置路徑畫刷的中心點

var
　 g: TGPGraphics;
　 path: TGPGraphicsPath;
　 pb: TGPPathGradIEntBrush;
　 num: Integer;
const
　 colors : array[0..0] of TGPColor = (aclAqua);
begin
　 g := TGPGraphics.Create(Canvas.Handle);
　 path:= TGPGraphicsPath.Create;
　 path.AddEllipse(0, 0, 140, 70);
　 pb:= TGPPathGradIEntBrush.Create(path);
　 pb.SetCenterPoint(MakePoint(120, 40)); {設置中心點}
　 pb.SetCenterColor(MakeColor(255, 0, 0, 255));
　 num := 1;
　 pb.SetSurroundColors(@colors, num);
　 g.FillEllipse(pb, 0, 0, 140, 70);
　 path.Free;
　 pb.Free;
　 g.Free;
end;

//使用灰度校正

var
　 g: TGPGraphics;
　 path: TGPGraphicsPath;
　 pb: TGPPathGradIEntBrush;
　 num: Integer;
const
　 colors: array[0..0] of TGPColor = (aclAqua);
begin
　 g := TGPGraphics.Create(Canvas.Handle);
　 path := TGPGraphicsPath.Create;
　 path.AddEllipse(0,0,166,88);
　 pb := TGPPathGradIEntBrush.Create(path);
　 pb.SetGamMacorrection(True); {使用灰度校正}
　 num := 1;
　 pb.SetSurroundColors(@colors, num);
　 g.FillEllipse(pb, 0, 0, 166, 88);
　 path.Free;
　 pb.Free;
　 g.Free;
end;

//多種顏色及位置

var
　 g : TGPGraphics;
　 pts: array[0..2] of TGPPoint;
　 pb: TGPPathGradIEntBrush;
const
　 colors: array[0..2] of TGPColor = (aclGreen, aclAqua, aclBlue);
　 pos: array[0..2] of Single = (0.0, 0.25, 1.0); {顏色位置需要 >0、<1, 是百分百}
begin
　 g := TGPGraphics.Create(Canvas.Handle);
　 pts[0] := MakePoint(100, 0);
　 pts[1] := MakePoint(200, 200);
　 pts[2] := MakePoint(0, 200);
　 pb:= TGPPathGradIEntBrush.Create(PGPPoint(@pts), 3); {根據點數組指針建立路徑畫刷}
　 pb.SetInterpolationColors(@colors, @pos, 3); {設置顏色位置}
　 g.FillRectangle(pb, 0, 0, 200, 200);
　 pb.Free;
　 g.Free;
end;