Delphi 与 DirectX 之 DelphiX(89): TDIB.DrawAlphaMask();

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, DIB, StdCtrls, ExtCtrls;



type

  TForm1 = class(TForm)

    DXPaintBox1: TDXPaintBox;

    Button1: TButton;

    Button2: TButton;

    ColorBox1: TColorBox;

    ColorBox2: TColorBox;

    procedure FormCreate(Sender: TObject);

    procedure FormDestroy(Sender: TObject);

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



const str = '春';



var

  dib,dib1,dib2: TDIB;



procedure TForm1.FormCreate(Sender: TObject);

const

  ImgPath1 = 'C:\Temp\DX.jpg';

begin

  dib := TDIB.Create;

  dib1 := TDIB.Create;

  dib2 := TDIB.Create;



  dib.LoadFromFile(ImgPath1);



  DXPaintBox1.ClientWidth := dib.Width;

  DXPaintBox1.ClientHeight := dib.Height;

  DXPaintBox1.DIB.Assign(dib);



  dib1.Assign(dib);



  dib2.SetSize(dib.Width, dib.Height, 24);

  dib2.Canvas.Brush.Style := bsClear;

  dib2.Canvas.Font.Name := '黑体';

  dib2.Canvas.Font.Size := 90;

  dib2.Canvas.Font.Style := [fsBold];



  ColorBox1.Selected := clBlack;

  ColorBox2.Selected := clYellow;

end;



procedure TForm1.FormDestroy(Sender: TObject);

begin

  dib.Free;

  dib1.Free;

  dib2.Free;

end;



procedure TForm1.Button1Click(Sender: TObject);

begin

  dib1.Assign(dib);

  dib2.Fill(ColorBox1.Selected);

  dib2.Canvas.Font.Color := ColorBox2.Selected;

  dib2.Canvas.TextOut(0, 0, str);



  dib1.DrawAlphaMask(dib2, dib1, 0, 0, dib.Width, dib.Height, 0, 0);



  DXPaintBox1.DIB.Assign(dib1);

  DXPaintBox1.Repaint;

end;



procedure TForm1.Button2Click(Sender: TObject);

begin

  dib1.Assign(dib);

  dib2.Fill(ColorBox2.Selected);

  dib2.Canvas.Font.Color := ColorBox1.Selected;

  dib2.Canvas.TextOut(0, 0, str);



  dib1.DrawAlphaMask(dib2, dib1, 0, 0, dib.Width, dib.Height, 0, 0);



  DXPaintBox1.DIB.Assign(dib1);

  DXPaintBox1.Repaint;

end;



end.


 
   

窗体文件:

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object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 142

  ClientWidth = 226

  Color = clBtnFace

  Font.Charset = DEFAULT_CHARSET

  Font.Color = clWindowText

  Font.Height = -11

  Font.Name = 'Tahoma'

  Font.Style = []

  OldCreateOrder = False

  OnCreate = FormCreate

  OnDestroy = FormDestroy

  PixelsPerInch = 96

  TextHeight = 13

  object DXPaintBox1: TDXPaintBox

    Left = 8

    Top = 8

    Width = 81

    Height = 73

    AutoStretch = False

    Center = False

    KeepAspect = False

    Stretch = False

    ViewWidth = 0

    ViewHeight = 0

  end

  object Button1: TButton

    Left = 143

    Top = 78

    Width = 75

    Height = 25

    Caption = 'Button1'

    TabOrder = 0

    OnClick = Button1Click

  end

  object Button2: TButton

    Left = 143

    Top = 109

    Width = 75

    Height = 25

    Caption = 'Button2'

    TabOrder = 1

    OnClick = Button2Click

  end

  object ColorBox1: TColorBox

    Left = 143

    Top = 8

    Width = 81

    Height = 22

    ItemHeight = 16

    TabOrder = 2

  end

  object ColorBox2: TColorBox

    Left = 143

    Top = 36

    Width = 81

    Height = 22

    ItemHeight = 16

    TabOrder = 3

  end

end