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

本例效果图:

代码文件:

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.