SetInterpolationColors 與 SetSurroundColors 的區別
本例效果圖:
代碼文件:unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, ComCtrls, StdCtrls, ExtCtrls;
type
TForm1 = class(TForm)
procedure FormPaint(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
procedure TForm1.FormPaint(Sender: TObject);
const
colors: array[0..3] of TGPColor = (aclRed, aclYellow, aclGreen, aclBlue);
pos: array[0..3] of Single = (0.0, 0.2, 0.6, 1.0); {好像兩端數據必須要是 0 和 1}
var
g: TGPGraphics;
path: TGPGraphicsPath;
pb: TGPPathGradientBrush;
num: Integer;
pts: array of TGPPoint;
begin
g := TGPGraphics.Create(Canvas.Handle);
path := TGPGraphicsPath.Create;
{建立橢圓路徑, 並根據路徑建立路徑畫刷, 再用 SetInterpolationColors 設置顏色}
path.AddEllipse(MakeRect(10,10,150,150));
pb := TGPPathGradientBrush.Create(path);
pb.SetInterpolationColors(@colors, @pos, Length(pos));
g.FillPath(pb, path);
{根據橢圓路徑建立路徑畫刷, 再用 SetSurroundColors 設置顏色}
pb.Free;
pb := TGPPathGradientBrush.Create(path);
num := Length(pos);
pb.SetSurroundColors(@colors, num);
g.TranslateTransform(160, 0);
g.FillPath(pb, path);
{根據從橢圓路徑中提取出的點數組建立路徑畫刷, 再用 SetSurroundColors 設置顏色}
SetLength(pts, path.GetPointCount);
path.GetPathPoints(PGPPoint(pts), Length(pts));
pb.Free;
pb := TGPPathGradientBrush.Create(PGPPoint(pts), Length(pts));
pb.SetCenterColor(aclWhite); {此時中心會默認黑色, 我想要白色的}
num := Length(colors);
pb.SetSurroundColors(@colors, num);
g.TranslateTransform(160, 0);
g.FillPath(pb, path);
{根據從橢圓路徑中提取出的點數組建立路徑畫刷, 再用 SetInterpolationColors 設置顏色 }
// SetLength(pts, path.GetPointCount);
// path.GetPathPoints(PGPPoint(pts), Length(pts));
pb.Free;
pb := TGPPathGradientBrush.Create(PGPPoint(pts), Length(pts));
// pb.SetCenterColor(aclWhite); {這裡不需要中心色}
num := Length(colors);
pb.SetInterpolationColors(@colors, @pos, Length(pos));
g.TranslateTransform(160, 0);
g.FillPath(pb, path);
pb.Free;
path.Free;
g.Free;
end;
end.
窗體文件:object Form1: TForm1
Left = 0
Top = 0
Caption = 'Form1'
ClientHeight = 169
ClientWidth = 649
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
