WinAPI: 测试 BitBlt

最新推荐文章于 2023-10-11 15:49:03 发布

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最新推荐文章于 2023-10-11 15:49:03 发布

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本文介绍了一种使用BitBlt函数实现不同设备上下文间图像复制的技术，并通过实例展示了如何利用各种光栅操作码（ROP）进行图像合成与处理。

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BitBlt(
  DestDC: HDC;                  {目标 DC}
  X, Y, Width, Height: Integer; {目标位置与大小}
  SrcDC: HDC;                   {源 DC}
  XSrc, YSrc: Integer;          {源起始位置}
  Rop: DWORD                    {光栅操作码, 也就是源像素与目标像素的混合方式}
): BOOL;

//可以使用光栅操作码的函数还有: PatBlt、StretchBlt、StretchDIBits

本例效果图:

代码文件:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    Panel1: TPanel;
    Panel2: TPanel;
    Panel3: TPanel;
    ListBox1: TListBox;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
    procedure FormPaint(Sender: TObject);
    procedure ListBox1Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

var
  bit1,bit2: TBitmap;
  cvs1,cvs2,cvs3: TCanvas;

procedure TForm1.FormCreate(Sender: TObject);
begin
  with ListBox1.Items do
  begin
    Add('SRCCOPY    ');
    Add('SRCPAINT   ');
    Add('SRCAND     ');
    Add('SRCINVERT  ');
    Add('SRCERASE   ');
    Add('NOTSRCCOPY ');
    Add('NOTSRCERASE');
    Add('MERGECOPY  ');
    Add('MERGEPAINT ');
    Add('PATCOPY    ');
    Add('PATPAINT   ');
    Add('PATINVERT  ');
    Add('DSTINVERT  ');
    Add('BLACKNESS  ');
    Add('WHITENESS  ');
  end;

  Panel1.Caption := '';
  Panel2.Caption := '';
  Panel3.Caption := '';

  bit1 := TBitmap.Create;
  bit1.Width := Panel1.ClientWidth;
  bit1.Height := Panel1.ClientHeight;

  bit2 := TBitmap.Create;
  bit2.Width := Panel2.ClientWidth;
  bit2.Height := Panel2.ClientHeight;


  cvs1 := TCanvas.Create;
  cvs2 := TCanvas.Create;
  cvs3 := TCanvas.Create;

  cvs1.Handle := GetDC(Panel1.Handle);
  cvs2.Handle := GetDC(Panel2.Handle);
  cvs3.Handle := GetDC(Panel3.Handle);
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  bit1.Free;
  bit2.Free;
  cvs1.Free;
  cvs2.Free;
  cvs3.Free;
end;

procedure TForm1.FormPaint(Sender: TObject);
const
  ColorArr: array[0..5] of TColor = (clRed, clGreen, clBlue, clYellow, clFuchsia, clPurple);
var
  wi,hi: Integer;
  I: Integer;
begin
  wi := bit1.Width div 4;
  hi := bit1.Height div 4;

  bit1.Canvas.Pen.Width := 10;

  for I := 1 to 3 do
  begin
    bit1.Canvas.Pen.Color := ColorArr[i-1];
    bit1.Canvas.MoveTo(wi*i, 0);
    bit1.Canvas.LineTo(wi*i, bit1.Height);

    bit1.Canvas.Pen.Color := ColorArr[i+2];
    bit1.Canvas.MoveTo(0, hi*i);
    bit1.Canvas.LineTo(bit1.Width, hi*i);
  end;

  bit2.Canvas.Pen.Width := 15;
  bit2.Canvas.Ellipse(15, 15, bit2.Width-15, bit2.Height-15);

  cvs1.Draw(0, 0, bit1);
  cvs2.Draw(0, 0, bit2);
end;

procedure TForm1.ListBox1Click(Sender: TObject);
var
  Rop: Cardinal;
begin
  Repaint;
  Rop := SRCCOPY;
  case ListBox1.ItemIndex of
    0 : Rop := SRCCOPY    ;
    1 : Rop := SRCPAINT   ;
    2 : Rop := SRCAND     ;
    3 : Rop := SRCINVERT  ;
    4 : Rop := SRCERASE   ;
    5 : Rop := NOTSRCCOPY ;
    6 : Rop := NOTSRCERASE;
    7 : Rop := MERGECOPY  ;
    8 : Rop := MERGEPAINT ;
    9 : Rop := PATCOPY    ;
    10: Rop := PATPAINT   ;
    11: Rop := PATINVERT  ;
    12: Rop := DSTINVERT  ;
    13: Rop := BLACKNESS  ;
    14: Rop := WHITENESS  ;
  end;

  cvs3.Draw(0, 0, bit1);
  BitBlt(cvs3.Handle, (bit1.Width - bit2.Width) div 2, (bit1.Height - bit2.Height) div 2,
    bit2.Width, bit2.Height, bit2.Canvas.Handle, 0, 0, Rop);
end;

end.

窗体文件:

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 300
  ClientWidth = 319
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  Position = poDesktopCenter
  OnCreate = FormCreate
  OnDestroy = FormDestroy
  OnPaint = FormPaint
  PixelsPerInch = 96
  TextHeight = 13
  object Panel1: TPanel
    Left = 8
    Top = 8
    Width = 180
    Height = 140
    Caption = 'Panel1'
    TabOrder = 0
  end
  object Panel2: TPanel
    Left = 194
    Top = 8
    Width = 119
    Height = 105
    Caption = 'Panel2'
    TabOrder = 1
  end
  object Panel3: TPanel
    Left = 8
    Top = 154
    Width = 180
    Height = 140
    Caption = 'Panel3'
    TabOrder = 2
  end
  object ListBox1: TListBox
    Left = 194
    Top = 119
    Width = 119
    Height = 176
    ItemHeight = 13
    TabOrder = 3
    OnClick = ListBox1Click
  end
end