再学GDI+[100]: TGPImage(20)

本例效果图:

代码文件:unit Unit1;
interface
uses
　Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
　Dialogs, StdCtrls, TeCanvas;
type
　TForm1 = class(TForm)
　　ButtonColor1: TButtonColor;
　　Button1: TButton;
　　procedure FormCreate(Sender: TObject);
　　procedure FormDestroy(Sender: TObject);
　　procedure FormPaint(Sender: TObject);
　　procedure ButtonColor1Click(Sender: TObject);
　　procedure FormMouseUp(Sender: TObject; Button: TMouseButton;
　　　Shift: TShiftState; X, Y: Integer);
　　procedure Button1Click(Sender: TObject);
　end;
var
　Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
var
　img: TGPImage;
　ImageAttributes: TGPImageAttributes;
　ColorMap: array[0..0] of TColorMap; {每个元素包含新旧两种颜色}
procedure TForm1.FormCreate(Sender: TObject);
begin
　img := TGPImage.Create('c:\temp\test.png');
　ClientWidth := img.GetWidth;
　ClientHeight := img.GetHeight;
　ImageAttributes := TGPImageAttributes.Create;
　ColorMap[0].oldColor := aclBlack;
　ColorMap[0].newColor := aclBlack;
　ButtonColor1.Caption := '替换';
　Button1.Caption := '复原';
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
　img.Free;
　ImageAttributes.Free;
end;
procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton;
　Shift: TShiftState; X, Y: Integer);
var
　color: TColor;
begin
　color := GetPixel(Canvas.Handle, X, Y);
　ColorMap[0].oldColor := ColorRefToARGB(color);
　ButtonColor1.SymbolColor := color;
　ButtonColor1.Refresh;
end;
procedure TForm1.FormPaint(Sender: TObject);
var
　g: TGPGraphics;
begin
　g := TGPGraphics.Create(Canvas.Handle);
　g.DrawImage(img,
　　　　　　　MakeRect(0, 0, img.GetWidth, img.GetHeight),
　　　　　　　0, 0,
　　　　　　　img.GetWidth, img.GetHeight,
　　　　　　　UnitPixel,
　　　　　　　ImageAttributes
　　　　　　　);
　g.Free;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
　ButtonColor1.SymbolColor := ARGBToColorRef(ColorMap[0].OldColor);
　ButtonColor1.Enabled := True;
　ButtonColor1.Update;
　ImageAttributes.ClearRemapTable; {ClearRemapTable}
　Repaint;
end;
procedure TForm1.ButtonColor1Click(Sender: TObject);
begin
　ColorMap[0].newColor := ColorRefToARGB(ButtonColor1.SymbolColor);
　ImageAttributes.SetRemapTable(Length(ColorMap), @ColorMap); {SetRemapTable}
　Repaint;
　ButtonColor1.Enabled := False;
end;
end.