Delphi 与 DirectX 之 DelphiX(26): TDIB 的主要载体 - TDXPaintBox

TDXPaintBox 和 TPaintBox 一样拥有重要的属性 Canvas;

现在要关心的是 TDXPaintBox 另一个主要属性: DIB(TDIB 对象);
在下面学习 TDIB 时, 应该会大量用到这个 TDXPaintBox.

虽然叫它 TDXPaintBox, 但我觉得它更像 TImage, 只是把 TImage.Picture 换做了 TDXPaintBox.DIB.

在设计时可以给 TDXPaintBox 的 DIB 对象添加图片, 不过本例是运行时添加的; 运行效果图:

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另外, 这是本例中的图片, 应右键另存到 C:\Temp\DX.jpg :

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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;



type

  TForm1 = class(TForm)

    DXPaintBox1: TDXPaintBox;

    Button1: TButton;

    Button2: TButton;

    Button3: TButton;

    procedure FormCreate(Sender: TObject);

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

    procedure Button3Click(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



var

  w,h: Integer;



procedure TForm1.Button1Click(Sender: TObject);

begin

  DXPaintBox1.Width := w div 2;

  DXPaintBox1.Height := w div 2;

end;



procedure TForm1.Button2Click(Sender: TObject);

begin

  DXPaintBox1.Width := ClientWidth;

  DXPaintBox1.Height := ClientHeight;

end;



procedure TForm1.Button3Click(Sender: TObject);

begin

  DXPaintBox1.Width := w;

  DXPaintBox1.Height := h;

end;



procedure TForm1.FormCreate(Sender: TObject);

const

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

begin

  DXPaintBox1.Left := 0;

  DXPaintBox1.Top := 0;



  DXPaintBox1.DIB.LoadFromFile(ImgPath1); {!}



  w := DXPaintBox1.DIB.Width;

  h := DXPaintBox1.DIB.Height;



  DXPaintBox1.Width := w;

  DXPaintBox1.Height := h;



  DXPaintBox1.Stretch := True;

end;



end.


 
   

窗体文件:

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object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 165

  ClientWidth = 225

  Color = clBtnFace

  Font.Charset = DEFAULT_CHARSET

  Font.Color = clWindowText

  Font.Height = -11

  Font.Name = 'Tahoma'

  Font.Style = []

  OldCreateOrder = False

  OnCreate = FormCreate

  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 = 23

    Top = 132

    Width = 60

    Height = 25

    Caption = 'Button1'

    TabOrder = 0

    OnClick = Button1Click

  end

  object Button2: TButton

    Left = 89

    Top = 132

    Width = 60

    Height = 25

    Caption = 'Button2'

    TabOrder = 1

    OnClick = Button2Click

  end

  object Button3: TButton

    Left = 157

    Top = 132

    Width = 60

    Height = 25

    Caption = 'Button3'

    TabOrder = 2

    OnClick = Button3Click

  end

end