再學 GDI+[100]: TGPImage(20) - 替換顏色

本例效果圖:

　　代碼文件: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; {每個元素包含新舊兩種顏色}
procedure TForm1.FormCreate(Sender: TObject);
begin
　img := TGPImage.Create('c:temptest.png');
　ClIEntWidth := img.GetWidth;
　ClIEntHeight := img.GetHeight;
　ImageAttributes := TGPImageAttributes.Create;
　ColorMap[0].oldColor := aclBlack;
　ColorMap[0].newColor := aclBlack;
　ButtonColor1.Caption := '替換';
　Button1.Caption := '復原';
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.窗體文件:object Form1: TForm1
　Left = 0
　Top = 0
　Caption = 'Form1'
　ClIEntHeight = 220
　ClIEntWidth = 315
　Color = clBtnFace
　Font.Charset = DEFAULT_CHARSET
　Font.Color = clWindowText
　Font.Height = -11
　Font.Name = 'Tahoma'
　Font.Style = []
　OldCreateOrder = False
　Position = poDesktopCenter
　OnCreate = FormCreate
　OnDestroy = FormDestroy
　OnMouseUp = FormMouseUp
　OnPaint = FormPaint
　PixelsPerInch = 96
　TextHeight = 13
　object ButtonColor1: TButtonColor
　　Left = 231
　　Top = 8
　　Caption = 'ButtonColor1'
　　TabOrder = 0
　　OnClick = ButtonColor1Click
　end
　object Button1: TButton
　　Left = 231
　　Top = 39
　　Width = 75
　　Height = 25
　　Caption = 'Button1'
　　TabOrder = 1
　　OnClick = Button1Click
　end
end