GDI+ 有五种画刷:

实心画刷: IGPSolidBrush
阴影画刷: IGPHatchBrush
纹理画刷: IGPTextureBrush
线性渐变画刷: IGPLinearGradientBrush
路径渐变画刷: IGPPathGradientBrush

它们分别有对应的实现类:
TGPSolidBrush
TGPHatchBrush
TGPTextureBrush
TGPLinearGradientBrush
TGPPathGradientBrush.

五个画刷都继承自 IGPBrush, 但 IGPBrush 只能通过其子类实现, 没有对应的 TGPBrush.

IGPBrush 只有两个有意义的成员:
IGPBrush.Clone 方法: 克隆对象; 系列中大多接口提供了这个方法以方便对象复制.
IGPBrush.BrushType 只读属性: 其对应的枚举当然会有五个元素, 分别对应上面五种画刷.

下面的例子是 BrushType 属性的测试:

uses GdiPlus, TypInfo;procedure TForm1.Button1Click(Sender: TObject);
varB1,B2,B3,B4,B5: IGPBrush; //定义五个画刷, 将要生成五种不同类型的画刷T1,T2,T3,T4,T5: string;   //用于获取画刷类型C1,C2: TGPColor;Pt1,Pt2: TGPPoint;Image: IGPImage;Path: IGPGraphicsPath;
begin{生成下面画刷需要的参数}C1 := $FFFF0000;C2 := $FF666666;Pt1.Initialize(0, 0);Pt2.Initialize(10, 10);Image := TGPImage.Create('C:\GdiPlusImg\Texture.jpg');Path := TGPGraphicsPath.Create;Path.AddEllipse(0, 0, 10, 10);{分别生成五种不同类型的画刷}B1 := TGPSolidBrush.Create(C1);B2 := TGPHatchBrush.Create(HatchStyleHorizontal, C1, C2);B3 := TGPTextureBrush.Create(Image);B4 := TGPLinearGradientBrush.Create(Pt1, Pt2, C1, C2);B5 := TGPPathGradientBrush.Create(Path);{获取各画刷的枚举名称}T1 := GetEnumName(TypeInfo(TGPBrushType), Ord(B1.BrushType));T2 := GetEnumName(TypeInfo(TGPBrushType), Ord(B2.BrushType));T3 := GetEnumName(TypeInfo(TGPBrushType), Ord(B3.BrushType));T4 := GetEnumName(TypeInfo(TGPBrushType), Ord(B4.BrushType));T5 := GetEnumName(TypeInfo(TGPBrushType), Ord(B5.BrushType));ShowMessage(T1); //BrushTypeSolidColorShowMessage(T2); //BrushTypeHatchFillShowMessage(T3); //BrushTypeTextureFillShowMessage(T4); //BrushTypePathGradientShowMessage(T5); //BrushTypeLinearGradient
end;

有必要先总览一下各画刷的基本效果, 下面是测试程序:

unit Unit1;interfaceusesWindows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,Dialogs, StdCtrls;typeTForm1 = class(TForm)Button1: TButton;Button2: TButton;Button3: TButton;Button4: TButton;Button5: TButton;procedure Button1Click(Sender: TObject);procedure Button2Click(Sender: TObject);procedure Button3Click(Sender: TObject);procedure Button4Click(Sender: TObject);procedure Button5Click(Sender: TObject);procedure FormCreate(Sender: TObject);end;varForm1: TForm1;implementation{$R *.dfm}uses GdiPlus, GdiPlusHelpers;var Rect: TGPRect = (X: 30; Y: 10; Width: 150; Height: 200);procedure TForm1.Button1Click(Sender: TObject);
varBrush: IGPSolidBrush;
beginBrush := TGPSolidBrush.Create($FFFF0000);Canvas.ToGPGraphics.FillEllipse(Brush, Rect);
end;procedure TForm1.Button2Click(Sender: TObject);
varBrush: IGPHatchBrush;
beginBrush := TGPHatchBrush.Create(HatchStyleDiagonalCross, $FF0000FF, $FFCCCCCC);Canvas.ToGPGraphics.FillEllipse(Brush, Rect);
end;procedure TForm1.Button3Click(Sender: TObject);
varBrush: IGPTextureBrush;
beginBrush := TGPTextureBrush.Create(TGPImage.Create('C:\GdiPlusImg\Texture.jpg'));Canvas.ToGPGraphics.FillEllipse(Brush, Rect);
end;procedure TForm1.Button4Click(Sender: TObject);
varBrush: IGPLinearGradientBrush;
beginBrush := TGPLinearGradientBrush.Create(Rect, $FFFF0000, $FF0000FF, 90);Canvas.ToGPGraphics.FillEllipse(Brush, Rect);
end;procedure TForm1.Button5Click(Sender: TObject);
varBrush: IGPPathGradientBrush;Path: IGPGraphicsPath;
beginPath := TGPGraphicsPath.Create;Path.AddEllipse(Rect);Brush := TGPPathGradientBrush.Create(Path);Brush.CenterColor := $FFFF0000;Brush.SetSurroundColors([$FFFFFF00]);Canvas.ToGPGraphics.FillEllipse(Brush, Rect);
end;procedure TForm1.FormCreate(Sender: TObject);
beginButton1.Caption := '实心画刷';Button2.Caption := '阴影画刷';Button3.Caption := '纹理画刷';Button4.Caption := '线性渐变画刷';Button5.Caption := '路径渐变画刷';
end;end.

测试效果图: