再学 GDI+[91]: TGPImage(11) 转灰度图像

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;

type
  TForm1 = class(TForm)
    CheckBox1: TCheckBox;
    procedure FormCreate(Sender: TObject);
    procedure FormPaint(Sender: TObject);
    procedure CheckBox1Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses GDIPOBJ, GDIPAPI;

const
  {一般模式}
  ColorMatrix1: TColorMatrix = (
    (1.0, 0.0, 0.0, 0.0, 0.0),
    (0.0, 1.0, 0.0, 0.0, 0.0),
    (0.0, 0.0, 1.0, 0.0, 0.0),
    (0.0, 0.0, 0.0, 1.0, 0.0),
    (0.0, 0.0, 0.0, 0.0, 1.0));

  {灰度模式}
  ColorMatrix2: TColorMatrix = (
    (0.3,  0.3,  0.3,  0.0, 0.0),
    (0.59, 0.59, 0.59, 0.0, 0.0),
    (0.11, 0.11, 0.11, 0.0, 0.0),
    (0.0,  0.0,  0.0,  1.0, 0.0),
    (0.0,  0.0,  0.0,  0.0, 1.0));

procedure TForm1.FormCreate(Sender: TObject);
begin
  CheckBox1.Caption := '转为灰度';
end;

procedure TForm1.FormPaint(Sender: TObject);
var
  g: TGPGraphics;
  img: TGPImage;
  ImageAttributes: TGPImageAttributes;
begin
  g := TGPGraphics.Create(Canvas.Handle);
  img := TGPImage.Create('c:\temp\test.png');

  ImageAttributes := TGPImageAttributes.Create;

  if CheckBox1.Checked then
    ImageAttributes.SetColorMatrix(ColorMatrix2)
  else
    ImageAttributes.SetColorMatrix(ColorMatrix1);

  g.DrawImage(img,
              MakeRect(4, 4, img.GetWidth, img.GetHeight),
              0,
              0,
              img.GetWidth,
              img.GetHeight,
              UnitPixel,
              ImageAttributes
              );

  ImageAttributes.Free;
  img.Free;
  g.Free;
end;

procedure TForm1.CheckBox1Click(Sender: TObject);
begin
  Repaint;
end;

end.

窗体文件:

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object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 216
  ClientWidth = 269
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  Position = poDesktopCenter
  OnCreate = FormCreate
  OnPaint = FormPaint
  PixelsPerInch = 96
  TextHeight = 13
  object CheckBox1: TCheckBox
    Left = 183
    Top = 191
    Width = 79
    Height = 17
    Caption = 'CheckBox1'
    TabOrder = 0
    OnClick = CheckBox1Click
  end
end