unit1.cpp

本书《C++Builder与WindowsAPI经典范例》附含配套光盘包括132个WindowsAPI函数及206个完整、可执行的实例

//---------------------------------------------------------------------------
#include <vcl.h>
#pragma hdrstop

#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
    : TForm(Owner)
{//先隐藏Image1图像，以免干扰显示成果
Image1->Hide();
Tag = 0;//将闲置属性，作为递增变量
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button1Click(TObject *Sender)
{//取得Form1的DC handle
HDC hdc = Canvas->Handle;
int setMode;
switch(Tag%4)
   {
   case 0: setMode = BLACKONWHITE; break;
   case 1: setMode = WHITEONBLACK; break;
   case 2: setMode = HALFTONE; break;
   case 3: setMode = COLORONCOLOR; break;
   }
//重设置图像伸展时模式
::SetStretchBltMode(hdc, setMode);
Tag++; //递增变数
//设置笔刷在SetStretchBltMode起始&范围，