再学 GDI+[100]: TGPImage(20) - 替换颜色

本例效果图:

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代码文件:

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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.


 
   

窗体文件:

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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