再学GDI+[65]: 路径画刷（5） - SetGammaCorrection

再学GDI+[65]: 路径画刷（5） - SetGammaCorrection2012-05-14 cnblogs 万一本例效果图:

代码文件:

unit Unit1;
interface
uses
 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
 Dialogs;
type
 TForm1 = class（TForm）
  procedure FormPaint（Sender: TObject）;
 end;
var
 Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
procedure TForm1.FormPaint（Sender: TObject）;
const
 ColorArr: array[0..2] of TGPColor = （aclRed, aclGreen, aclBlue）;
var
 pts: array[0..2] of TGPPoint;
 g: TGPGraphics;
 path: TGPGraphicsPath;
 pb: TGPPathGradientBrush;
 num: Integer;
begin
 pts[0] := MakePoint（80, 10）;
 pts[1] := MakePoint（10, 150）;
 pts[2] := MakePoint（150, 150）;
 g := TGPGraphics.Create（Canvas.Handle）;
 path := TGPGraphicsPath.Create;
 path.AddPolygon（PGPPoint（@pts）, Length（pts））;
 //pb := TGPPathGradientBrush.Create（path）; {这样建立中心默认白色; 按下一句中心默 认黑色}
 pb := TGPPathGradientBrush.Create（PGPPoint（@pts）, Length（pts））; {根据点数组建立路 径画刷}
 pb.SetCenterColor（aclWhite）;
 num := Length（pts）;
 pb.SetSurroundColors（PARGB（@ColorArr）, num）;
 g.FillPath（pb, path）;
 {使用灰度校正模式换个地方再画一次}
 pb.SetGammaCorrection（True）;
 g.TranslateTransform（150, 0）;
 g.FillPath（pb, path）;
 pb.Free;
 path.Free;
 g.Free;
end;
end.

窗体文件:

object Form1: TForm1
 Left = 0
 Top = 0
 Caption = "Form1"
 ClientHeight = 163
 ClientWidth = 311
 Color = clBtnFace
 Font.Charset = DEFAULT_CHARSET
 Font.Color = clWindowText
 Font.Height = -11
 Font.Name = "Tahoma"
 Font.Style = []
 OldCreateOrder = False
 Position = poDesktopCenter
 OnPaint = FormPaint
 PixelsPerInch = 96
 TextHeight = 13
end