Visual C++位图操作（转）

一.BitBlt

将一幅位图从一个设备场景复制到另一个,即复制像素,前面参数为目标,后者为源

case   WM_PAINT:
               hdcClient = BeginPaint (hwnd, &ps) ;
               hdcWindow = GetWindowDC (hwnd) ;
               for (y = 0 ; y < cyClient ; y += cySource)
                   for (x = 0 ; x < cxClient ; x += cxSource)
                   {
                          BitBlt (hdcClient, x, y, cxSource, cySource,
                          hdcWindow, 0, 0, SRCCOPY) ;
                   }
               ReleaseDC (hwnd, hdcWindow) ;
               EndPaint (hwnd, &ps) ;
               return 0 ;

二.拉伸位图(会使图片不清晰)

使用StretchBlt函数,比BitBlt多了两个参数

case   WM_PAINT:
               hdcClient = BeginPaint (hwnd, &ps) ;
               hdcWindow = GetWindowDC (hwnd) ;
              StretchBlt (hdcClient, 0, 0, cxClient, cyClient,
                    hdcWindow, 0, 0, cxSource, cySource, MERGECOPY) ;
               ReleaseDC (hwnd, hdcWindow) ;
               EndPaint (hwnd, &ps) ;
               return 0 ;

三.创建位图

3.1

hBitmap = CreateCompatibleBitmap (hdc, cx, cy) ; 
        //此函数建立了一个与设备兼容的位图

hBitmap CreateBitmapIndirect (&bitmap) ;
//通过结构体创建

1. 先LoadBitmap 载入位图
2. 然后创建CreateCompatibleDC
3. BitBlt 拷贝像素

switch(message)
{
case   WM_CREATE:
               hInstance = ((LPCREATESTRUCT) lParam)->hInstance ;
               hBitmap = LoadBitmap (hInstance, TEXT ("Bricks")) ;
               GetObject (hBitmap, sizeof (BITMAP), &bitmap) ;
               cxSource = bitmap.bmWidth ;
               cySource = bitmap.bmHeight ;
               return 0 ;
case   WM_SIZE:
               cxClient = LOWORD (lParam) ;
               cyClient = HIWORD (lParam) ;
               return 0 ;
case   WM_PAINT:
               hdc = BeginPaint (hwnd, &ps) ;
               hdcMem = CreateCompatibleDC (hdc) ;
               SelectObject (hdcMem, hBitmap) ;
               for (y = 0 ; y < cyClient ; y += cySource)
                   for (x = 0 ; x < cxClient ; x += cxSource)
                   {
                     BitBlt (hdc, x, y, cxSource, cySource, hdcMem, 0, 0, SRCCOPY) ;
                   }
               DeleteDC (hdcMem) ;
               EndPaint (hwnd, &ps) ;
               return 0 ;
case   WM_DESTROY:
               DeleteObject (hBitmap) ;
               PostQuitMessage (0) ;
               return 0 ;
}

3.2用位图创建文字,用0和1表示,相当于画像素点的意思.

填充BITMAP的bmBits字段

 static BITMAP bitmap = {   0, 8, 8, 2, 1, 1 } ;
 static BYTE                   bits [8][2]={ 0xFF, 0, 0x0C, 0, 0x0C, 0, 0x0C, 0,
        
                                       0xFF, 0, 0xC0, 0, 0xC0, 0, 0xC0, 0 } ;
 static HBITMAP hBitmap ;
 static int                    cxClient, cyClient, cxSource, cySource ;
 HDC                           hdc, hdcMem ;
 int                           x, y ;
 PAINTSTRUCT                  ps ;
        
   
        
 switch (message)
        
{
        
 case   WM_CREATE:
        
                bitmap.bmBits = bits ;
        
                hBitmap       = CreateBitmapIndirect (&bitmap) ;
        
                cxSource      = bitmap.bmWidth ;
        
                cySource      = bitmap.bmHeight ;
        
                return 0 ;

3.3使用位图创建笔刷

hBitmap = LoadBitmap (hInstance, TEXT ("Bricks"));
hBrush = CreatePatternBrush (hBitmap);
DeleteObject (hBitmap);

3.4在位图中绘图

用CreateCompatibleBitmap 创建一幅与设备兼容有关位图,然后选择位图,SelectObject (hdcMem, hBitmap)

hdc = GetDC (hwnd) ;
hdcMem  = CreateCompatibleDC (hdc) ;
GetTextExtentPoint32 (hdc, szText, lstrlen (szText), &size);
cxBitmap = size.cx ;
cyBitmap = size.cy;
hBitmap = CreateCompatibleBitmap (hdc, cxBitmap, cyBitmap);
ReleaseDC (hwnd, hdc) ;
SelectObject (hdcMem, hBitmap) ;
TextOut (hdcMem, 0, 0, szText, lstrlen (szText));

创建好以后就可以同上方法用BitBlt或者StretchBlt方法操作像素了

四.菜单插入位图

hBitmap = StretchBitmap (LoadBitmap (hInstance, TEXT ("BitmapFont"))) ;
AppendMenu (hMenu, MF_BITMAP | MF_POPUP, (int) hMenuPopup,
                   (PTSTR) (LONG) hBitmap) ;