TDXPaintBox和TPaintBox一樣擁有重要的屬性 Canvas;
現在要關心的是TDXPaintBox另一個主要屬性: DIB(TDIB 對象);
在下面學習TDIB時, 應該會大量用到這個TDXPaintBox.
雖然叫它TDXPaintBox, 但我覺得它更像TImage, 只是把TImage.Picture換做了TDXPaintBox.DIB.
在設計時可以給TDXPaintBox 的DIB對象添加圖片, 不過本例是運行時添加的;運行效果圖:
另外, 這是本例中的圖片, 應右鍵另存到C:\Temp\DX.jpg :
代碼文件:
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.
窗體文件:
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
