14.4.10 非矩形的位图图像
（1）“掩码”位图——单色位图，要显示的像素对应的掩码置1，不显示置0
（2）光栅操作（点这里，见此文分析）
（3）MaskBlt函数
①MaskBlt(hdcDest, nXDest, nYDest, nWidth, nHeight, hdcSrc, nXSrc, nYSrc,hbmMask, xMask, yMask, dwRop)；
②前景和背景：在由hbmMask指定的掩码中，数值1表示在那个位置应使用dwRop指定的前景光栅操作码。数值0表示应使用dwRop指定的背景光栅操作码。
③用MAKEROP4(fore,back)组合光栅操作码
【BitMask程序】
效果图
/*------------------------------------------------------------ BITMASK.C -- Bitmap Masking Demonstration (c) Charles Petzold, 1998 ------------------------------------------------------------*/ #include <windows.h> LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow) { static TCHAR szAppName[] = TEXT("BitMask"); HWND hwnd; MSG msg; WNDCLASSEX wndclass; wndclass.style = CS_HREDRAW | CS_VREDRAW; wndclass.cbSize = sizeof(WNDCLASSEX); wndclass.lpfnWndProc = WndProc; wndclass.cbClsExtra = 0; wndclass.cbWndExtra = 0; wndclass.hInstance = hInstance; wndclass.hIcon = LoadIcon(hInstance, szAppName); wndclass.hIconSm = LoadIcon(hInstance, szAppName); wndclass.hCursor = LoadCursor(NULL, IDC_ARROW); wndclass.hbrBackground = (HBRUSH)GetStockObject(LTGRAY_BRUSH); //为了更好的效果，不用白色画刷 wndclass.lpszMenuName = NULL; wndclass.lpszClassName = szAppName; if (!RegisterClassEx(&wndclass)) { MessageBox(NULL, TEXT("This program requires Windows NT!"), szAppName, MB_ICONERROR); return 0; } hwnd = CreateWindow(szAppName, // window class name TEXT("Bitmap Masking Demo"), // window caption WS_OVERLAPPEDWINDOW, // window style CW_USEDEFAULT, // initial x position CW_USEDEFAULT, // initial y position CW_USEDEFAULT, // initial x size CW_USEDEFAULT, // initial y size NULL, // parent window handle NULL, // window menu handle hInstance, // program instance handle NULL); // creation parameters ShowWindow(hwnd, iCmdShow); UpdateWindow(hwnd); while (GetMessage(&msg, NULL, 0, 0)) { TranslateMessage(&msg); DispatchMessage(&msg); } return msg.wParam; } LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { PAINTSTRUCT ps; static int cxBitmap, cyBitmap, cxClient, cyClient; static HINSTANCE hInstance; static HBITMAP hBitmapImag, hBitmapMask; HDC hdc, hdcMemImag, hdcMemMask; BITMAP bitmap; int x, y; switch (message) { case WM_CREATE: hInstance = ((LPCREATESTRUCT)lParam)->hInstance; //加载原始图像并获取图像大小 hBitmapImag = LoadBitmap(hInstance, TEXT("Matthew")); GetObject(hBitmapImag, sizeof(BITMAP), &bitmap); cxBitmap = bitmap.bmWidth; cyBitmap = bitmap.bmHeight; //将原始图像选入内存DC hdcMemImag = CreateCompatibleDC(NULL); //这里用NULL没关系，只要是借个DC来修改原始图像 SelectObject(hdcMemImag, hBitmapImag); //创建单色掩码位图和内存DC hBitmapMask = CreateBitmap(cxBitmap, cyBitmap, 1, 1, NULL); //单色cxBitmap*cybitmap像素位图 hdcMemMask = CreateCompatibleDC(NULL); //这里用NULL没关系，只要是借个DC来修改掩码位图 SelectObject(hdcMemMask, hBitmapMask); //给掩码位图上色：矩形黑色，椭圆白色。 SelectObject(hdcMemMask, GetStockObject(BLACK_BRUSH)); Rectangle(hdcMemMask, 0, 0, cxBitmap, cyBitmap); SelectObject(hdcMemMask, GetStockObject(WHITE_BRUSH)); Ellipse(hdcMemMask, 0, 0, cxBitmap, cyBitmap); //遮罩原始图像，只显示椭圆内的图像 BitBlt(hdcMemImag, 0, 0, cxBitmap, cyBitmap, hdcMemMask, 0, 0, SRCAND); //这里用“与”操作，只显示掩码为1的，但周围是黑色的。 DeleteDC(hdcMemImag); //可以删除，因为图像操作结果己保存在hBitmapImag中了。 DeleteDC(hdcMemMask); //可以删除，因为图像操作结果己保存在hBitmapMask中了。 return 0; case WM_SIZE: cxClient = LOWORD(lParam); cyClient = HIWORD(lParam); return 0; case WM_PAINT: hdc = BeginPaint(hwnd, &ps); // hdcMemImag = CreateCompatibleDC(hdc); //这里要显示在客户区了，不用要NULL SelectObject(hdcMemImag, hBitmapImag); hdcMemMask = CreateCompatibleDC(hdc); SelectObject(hdcMemMask, hBitmapMask); x = (cxClient - cxBitmap) / 2; y = (cyClient - cyBitmap) / 2; ////掩码位图，至此是一个外部黑色的，里面为白色的椭圆 //0x220326=D&(~S)，让椭圆内部为黑，外部白色，再&D，此时屏幕上为一个黑色椭圆。 //BitBlt(hdc, x, y, cxBitmap, cyBitmap, hdcMemMask, 0, 0, 0x220326); //源和目标进行逻辑或运算，或的结果就是黑色，区域将源和目标重叠部分（椭圆区域）显示出来。 //BitBlt(hdc, x, y, cxBitmap, cyBitmap, hdcMemImag, 0, 0, SRCPAINT); //以上两句也可以用MaskBlt代替：MAKEROP4（fore,back），掩码为1为前景，掩码为0的地方为背景。 //因掩码图椭圆外为黑色，内部白色。因此前景的地方直接拷贝照片相应的地方（SRCCOPY）， //背景的地方用画刷去刷（SRCPAINT） MaskBlt(hdc, x, y, cxBitmap, cyBitmap, hdcMemImag, 0, 0, hBitmapMask, 0, 0, MAKEROP4(SRCCOPY, SRCPAINT)); DeleteDC(hdcMemImag); DeleteDC(hdcMemMask); EndPaint(hwnd, &ps); return 0; case WM_DESTROY: PostQuitMessage(0); return 0; } return DefWindowProc(hwnd, message, wParam, lParam); }
//resource.h
//{{NO_DEPENDENCIES}} // Microsoft Visual C++ 生成的包含文件。 // 供 BitMask.rc 使用 // // Next default values for new objects // #ifdef APSTUDIO_INVOKED #ifndef APSTUDIO_READONLY_SYMBOLS #define _APS_NEXT_RESOURCE_VALUE 102 #define _APS_NEXT_COMMAND_VALUE 40001 #define _APS_NEXT_CONTROL_VALUE 1001 #define _APS_NEXT_SYMED_VALUE 101 #endif #endif
//BitMask.rc
// Microsoft Visual C++ generated resource script. // #include "resource.h" #define APSTUDIO_READONLY_SYMBOLS ///////////////////////////////////////////////////////////////////////////// // // Generated from the TEXTINCLUDE 2 resource. // #include "winres.h" ///////////////////////////////////////////////////////////////////////////// #undef APSTUDIO_READONLY_SYMBOLS ///////////////////////////////////////////////////////////////////////////// // 中文(简体，中国) resources #if !defined(AFX_RESOURCE_DLL) || defined(AFX_TARG_CHS) LANGUAGE LANG_CHINESE, SUBLANG_CHINESE_SIMPLIFIED #ifdef APSTUDIO_INVOKED ///////////////////////////////////////////////////////////////////////////// // // TEXTINCLUDE // 1 TEXTINCLUDE BEGIN "resource.h " END 2 TEXTINCLUDE BEGIN "#include ""winres.h"" " " " END 3 TEXTINCLUDE BEGIN " " " " END #endif // APSTUDIO_INVOKED ///////////////////////////////////////////////////////////////////////////// // // Bitmap // MATTHEW BITMAP "Matthew.bmp" #endif // 中文(简体，中国) resources ///////////////////////////////////////////////////////////////////////////// #ifndef APSTUDIO_INVOKED ///////////////////////////////////////////////////////////////////////////// // // Generated from the TEXTINCLUDE 3 resource. // ///////////////////////////////////////////////////////////////////////////// #endif // not APSTUDIO_INVOKED
14.4.11 简单的动画效果
（1）利用BitBlt在内存设备环境中画出小球
（2）通过计时器实现动画
【Bounce程序】
效果图
/*------------------------------------------------------------ BOUNCE.C -- Bouncing Ball Program (c) Charles Petzold, 1998 ------------------------------------------------------------*/ #include <windows.h> #define ID_TIMER 1 LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow) { static TCHAR szAppName[] = TEXT("Bounce"); HWND hwnd; MSG msg; WNDCLASSEX wndclass; wndclass.style = CS_HREDRAW | CS_VREDRAW; wndclass.cbSize = sizeof(WNDCLASSEX); wndclass.lpfnWndProc = WndProc; wndclass.cbClsExtra = 0; wndclass.cbWndExtra = 0; wndclass.hInstance = hInstance; wndclass.hIcon = LoadIcon(hInstance, szAppName); wndclass.hIconSm = LoadIcon(hInstance, szAppName); wndclass.hCursor = LoadCursor(NULL, IDC_ARROW); wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH); wndclass.lpszMenuName = NULL; wndclass.lpszClassName = szAppName; if (!RegisterClassEx(&wndclass)) { MessageBox(NULL, TEXT("This program requires Windows NT!"), szAppName, MB_ICONERROR); return 0; } hwnd = CreateWindow(szAppName, // window class name TEXT("Bouncing Ball"), // window caption WS_OVERLAPPEDWINDOW, // window style CW_USEDEFAULT, // initial x position CW_USEDEFAULT, // initial y position CW_USEDEFAULT, // initial x size CW_USEDEFAULT, // initial y size NULL, // parent window handle NULL, // window menu handle hInstance, // program instance handle NULL); // creation parameters ShowWindow(hwnd, iCmdShow); UpdateWindow(hwnd); while (GetMessage(&msg, NULL, 0, 0)) { TranslateMessage(&msg); DispatchMessage(&msg); } return msg.wParam; } LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { static HBITMAP hBitmap; HDC hdc, hdcMem; HBRUSH hBrush; static int xPixel, yPixel, cxRadius, cyRadius, xCenter, yCenter, cxClient, cyClient, cxTotal, cyTotal, cxMove, cyMove; int iScale; switch (message) { case WM_CREATE: hdc = GetDC(hwnd); xPixel = GetDeviceCaps(hdc, ASPECTX); yPixel = GetDeviceCaps(hdc, ASPECTY); ReleaseDC(hwnd, hdc); SetTimer(hwnd, ID_TIMER, 50, NULL); return 0; case WM_SIZE: xCenter = (cxClient = LOWORD(lParam)) / 2; yCenter = (cyClient = HIWORD(lParam)) / 2; //小球的半径是客户区高、宽中较小一个的16分之一 iScale = min(cxClient*xPixel, cyClient*yPixel) / 16; cxRadius = iScale / xPixel; cyRadius = iScale / yPixel; //cxMove = 半径的1/2 cxMove = max(1, cxRadius / 2); cyMove = max(1, cyRadius / 2); //创建一个比球的尺寸多出半径一半的位图，目的是当图运动步长较小时，仍可以用后一张图 //覆盖住前一张，己实现擦图。 cxTotal = 2 * (cxRadius + cxMove); cyTotal = 2 * (cyRadius + cyMove); if (hBitmap) DeleteObject(hBitmap); hdc = GetDC(hwnd); hdcMem = CreateCompatibleDC(hdc); hBitmap = CreateCompatibleBitmap(hdc, cxTotal, cyTotal); //注意是hdc，而不是hdcMem ReleaseDC(hwnd, hdc); SelectObject(hdcMem, hBitmap); //将整个位图填上白色（含边框） Rectangle(hdcMem, -1, -1, cxTotal + 1, cyTotal + 1); //创建球，内部用对角线填充 hBrush = CreateHatchBrush(HS_DIAGCROSS, RGB(255, 0, 0)); SelectObject(hdcMem, hBrush); SetBkColor(hdcMem, RGB(255, 0, 255)); Ellipse(hdcMem, cxMove, cxMove, cxTotal - cxMove, cyTotal - cyMove); DeleteDC(hdcMem); DeleteObject(hBrush); return 0; case WM_TIMER: if (!hBitmap) break; hdc = GetDC(hwnd); hdcMem = CreateCompatibleDC(hdc); SelectObject(hdcMem, hBitmap); BitBlt(hdc, xCenter - cxTotal / 2, yCenter - cyTotal / 2, cxTotal, cyTotal, hdcMem, 0, 0, SRCCOPY); DeleteDC(hdcMem); ReleaseDC(hwnd, hdc); xCenter += cxMove; //因为步长小，后一幅图大小仍会将前一张图球的那部分覆盖掉 yCenter += cyMove; //从而实现了擦图，如果步长大的话就会留下痕迹。 if ((xCenter + cxRadius >= cxClient) || (xCenter - cxRadius <= 0)) cxMove = -cxMove; if ((yCenter + cyRadius >= cyClient) || (yCenter - cyRadius <= 0)) cyMove = -cyMove; return 0; case WM_DESTROY: if (hBitmap) DeleteObject(hBitmap); KillTimer(hwnd, ID_TIMER); PostQuitMessage(0); return 0; } return DefWindowProc(hwnd, message, wParam, lParam); }
14.4.12 窗口以外的位图
（1）GetDCEx：GetDCEx(HWND hWnd, HRGN hrgnClip, DWORD flags)
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flags的值 |
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DCX_WINDOW |
返回与窗口矩形而不是与客户矩形相对应 |
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DXC_CACHE |
从高速缓存而不是从OWNDC或CLASSDC窗口中返回设备环境。从本质上覆盖CS_OWNDC和CS_CLASSDC |
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DCX_PARENTCLIP |
使用父窗口的可见区域，父窗口的WS_CIPCHILDREN和CS_PARENTDC风格被忽略，并把设备DC环境的原点，设在由hWnd所标识的窗口的左上角 |
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DCX_CLIPSIBLINGS |
排除hWnd参数所标识窗口上的所有兄弟窗口的可见区域 |
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DCX_CLIPCHILDREN |
排除hWnd参数所标识窗口上的所有子窗口的可见区域 |
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DCX_NORESETATTRS |
当设备DC环境被释放时，并不重置该DC的特性为缺省特性 |
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DCX_LOCKWINDOWUPDATE |
即使在指定窗口被LockWindowUpdate的情况下也会绘制，该参数用于在跟踪期间进行绘制 |
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DCX_EXCLUDERGN |
从返回设备DC环境的可见区域中排除由hrgnClip指定的剪切区域 |
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DCX_INTERSECTRGN |
对hrgnClip指定的剪切区域与返回设备描述的可见区域作交运算 |
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DCX_VALIDATE |
当与DCX_INTERSECTUPDATE一起指定时，致使设备DC文环境完全有效，该函数与DCX_INTERSECTUPDATE和DCX_VALIDATE一起使用时与使用BeginPaint函数相同。 |
【Scramble程序】——打乱桌面并自动恢复（利用锁定屏幕更新技术）
效果图
/*---------------------------------------------------------------- SCRAMBLE.C —— Scramble (and UnScramble) Screen -----------------------------------------------------------------*/ #include <windows.h> #define NUM 200 //注意，这个程序没有窗口过程，只能WinMain主函数 int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PTSTR szCmdLine, int iCmdShow) { static int iKeep[NUM][4]; HDC hdcSrc, hdcMem; HBITMAP hBitmap; HWND hwnd; int cx, cy; int x1, y1, x2, y2; hwnd = GetDesktopWindow(); if (LockWindowUpdate(hwnd)) { //GetDCEx的参数DCX_LOCKWINDOWUPDATE确保本程序在屏幕锁定期间仍可更新屏幕 hdcSrc = GetDCEx(hwnd, NULL, DCX_CACHE | DCX_LOCKWINDOWUPDATE); hdcMem = CreateCompatibleDC(hdcSrc); cx = GetSystemMetrics(SM_CXSCREEN) / 10; //位图大小为屏幕的1/10 cy = GetSystemMetrics(SM_CYSCREEN) / 10; hBitmap = CreateCompatibleBitmap(hdcSrc, cx, cy); SelectObject(hdcMem, hBitmap); srand((int)GetCurrentTime()); for (int i = 0; i < 2; i++) for (int j = 0; j < NUM; j++) { if (i == 0) //打乱 { //rand（）产生0-RAND_MAX之间的数，其中RAND_MAX为0x7fff //随机产生两个矩形并保存起来 iKeep[j][0] = x1 = cx*(rand() % 10); iKeep[j][1] = y1 = cy*(rand() % 10); iKeep[j][2] = x2 = cx*(rand() % 10); iKeep[j][3] = y2 = cy*(rand() % 10); } else //恢复时，要后面开始 { x1 = iKeep[NUM - 1 - j][0]; y1 = iKeep[NUM - 1 - j][1]; x2 = iKeep[NUM - 1 - j][2]; y2 = iKeep[NUM - 1 - j][3]; } //交换两个矩形内的图像 BitBlt(hdcMem, 0, 0, cx, cy, hdcSrc, x1, y1, SRCCOPY); //第1张位图保存 BitBlt(hdcSrc, x1, y1, cx, cy, hdcSrc, x2, y2, SRCCOPY);//第2张位图复制到第1张的位置 BitBlt(hdcSrc, x2, y2, cx, cy, hdcMem, 0, 0, SRCCOPY); //从内存DC中复制第1张到第2张的位置 Sleep(2); } DeleteDC(hdcMem); ReleaseDC(hwnd, hdcSrc); DeleteObject(hBitmap); LockWindowUpdate(NULL); //屏幕解锁 } return 0; }
（2）屏幕截图
①剪贴板中使用位图时，可以不是全局句柄，而直接使用位图句柄
②SetStretchBltMode(hdc, COLORONCOLOR);//缩小图片时，删除所有消除的像素行，不保留其信息
【BlowUp程序】——操作方法
①在客户区按下鼠标左键，鼠标变成十字形。
②在按键左键的同时，将指针移到屏幕任意地方，放在要截图位置的左上角。
③保持按住左键的同时，按下右键，并拖出一个矩形框（会反色显示）的右下角，再松开鼠标（松开顺序无关紧要）
④如果从右上角向左下角选取，可以得到左右相反图像。从左下向右上角选择会得到上下相反的图像。从右下向左上，会出现上下、左右都相反的图像。
效果图
/*------------------------------------------------------------ BLOWUP.C -- Video Magnifier Program （放大镜） (c) Charles Petzold, 1998 ------------------------------------------------------------*/ #include <windows.h> #include "resource.h" LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow) { static TCHAR szAppName[] = TEXT("BlowUp"); HWND hwnd; MSG msg; WNDCLASSEX wndclass; HACCEL hAccel; wndclass.style = CS_HREDRAW | CS_VREDRAW; wndclass.cbSize = sizeof(WNDCLASSEX); wndclass.lpfnWndProc = WndProc; wndclass.cbClsExtra = 0; wndclass.cbWndExtra = 0; wndclass.hInstance = hInstance; wndclass.hIcon = LoadIcon(hInstance, szAppName); wndclass.hIconSm = LoadIcon(hInstance, szAppName); wndclass.hCursor = LoadCursor(NULL, IDC_ARROW); wndclass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH); wndclass.lpszMenuName = szAppName; wndclass.lpszClassName = szAppName; if (!RegisterClassEx(&wndclass)) { MessageBox(NULL, TEXT("This program requires Windows NT!"), szAppName, MB_ICONERROR); return 0; } hwnd = CreateWindow(szAppName, // window class name TEXT("Blow-UP Mouse Demo"), // window caption WS_OVERLAPPEDWINDOW, // window style CW_USEDEFAULT, // initial x position CW_USEDEFAULT, // initial y position CW_USEDEFAULT, // initial x size CW_USEDEFAULT, // initial y size NULL, // parent window handle NULL, // window menu handle hInstance, // program instance handle NULL); // creation parameters ShowWindow(hwnd, iCmdShow); UpdateWindow(hwnd); hAccel = LoadAccelerators(hInstance, szAppName); while (GetMessage(&msg, NULL, 0, 0)) { if (!TranslateAccelerator(hwnd, hAccel, &msg)) { TranslateMessage(&msg); DispatchMessage(&msg); } } return msg.wParam; } //将目标矩形内颜色取反，以表示被选中的区域 void InvertBlock(HWND hwndSrc, HWND hwnd, POINT ptBeg, POINT ptEnd) { HDC hdc; hdc = GetDCEx(hwndSrc, NULL, DCX_CACHE | DCX_LOCKWINDOWUPDATE); //获屏幕DC并允许锁屏期间也可绘图 ClientToScreen(hwnd, &ptBeg); //因为屏幕捕获的原因，这里传进来的是客户区坐标 ClientToScreen(hwnd, &ptEnd); PatBlt(hdc, ptBeg.x, ptBeg.y, ptEnd.x - ptBeg.x, ptEnd.y - ptBeg.y, DSTINVERT); //DSTINVERT：将目标矩形反向。 ReleaseDC(hwndSrc, hdc); } //复制位图 HBITMAP CopyBitmap(HBITMAP hBitmapSrc) { HBITMAP hBitmapDst; //目标位图 BITMAP bitmap; HDC hdcSrc, hdcDst; GetObject(hBitmapSrc, sizeof(BITMAP), &bitmap); hBitmapDst = CreateBitmapIndirect(&bitmap); hdcSrc = CreateCompatibleDC(NULL); //NULL，只是借助桌面DC来复制位图而己 hdcDst = CreateCompatibleDC(NULL); //NULL，只是借助桌面DC来复制位图而己 SelectObject(hdcSrc, hBitmapSrc); SelectObject(hdcDst, hBitmapDst); BitBlt(hdcDst, 0, 0, bitmap.bmWidth, bitmap.bmHeight, hdcSrc, 0, 0, SRCCOPY); DeleteDC(hdcDst); DeleteDC(hdcSrc); return hBitmapDst; //hBitmapDst是局部变量，但这里是值拷贝，会复制一个 //hBitmapDst返回 } LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { static BOOL bCapturing, bBlocking; //正在鼠标捕获和正在画矩形块 static POINT ptBeg, ptEnd; static HBITMAP hBitmap; HBITMAP hBitmapClip; BITMAP bm; static HWND hwndSrc; HDC hdc, hdcMem; PAINTSTRUCT ps; RECT rect; int iEnable; switch (message) { case WM_CREATE: return 0; case WM_INITMENUPOPUP: //wParam:handle to menu; lparam:item position and indicator iEnable = IsClipboardFormatAvailable(CF_BITMAP) ? MF_ENABLED : MF_GRAYED; EnableMenuItem((HMENU)(wParam), IDM_EDIT_PASTE, iEnable); iEnable = hBitmap ? MF_ENABLED : MF_GRAYED; EnableMenuItem((HMENU)(wParam), IDM_EDIT_COPY, iEnable); EnableMenuItem((HMENU)(wParam), IDM_EDIT_CUT, iEnable); EnableMenuItem((HMENU)(wParam), IDM_EDIT_CLEAR, iEnable); return 0; case WM_COMMAND: switch (LOWORD(wParam)) //菜单ID { case IDM_EDIT_CUT: case IDM_EDIT_COPY: if (hBitmap) { hBitmapClip = CopyBitmap(hBitmap); OpenClipboard(hwnd); EmptyClipboard(); SetClipboardData(CF_BITMAP, hBitmapClip); //位图时，可以是位图句柄，而不用全局句柄 if (LOWORD(wParam) == IDM_EDIT_COPY) return 0; //剪切时，继续执行下云 } case IDM_EDIT_CLEAR: if (hBitmap) { DeleteObject(hBitmap); hBitmap = NULL; } InvalidateRect(hwnd, NULL, TRUE); return 0; case IDM_EDIT_PASTE: if (hBitmap) { DeleteObject(hBitmap); hBitmap = NULL; } OpenClipboard(hwnd); hBitmapClip = GetClipboardData(CF_BITMAP); if (hBitmapClip) { hBitmap = CopyBitmap(hBitmapClip); } CloseClipboard(); InvalidateRect(hwnd, NULL, TRUE); return 0; } break; case WM_LBUTTONDOWN: if (!bCapturing) { hwndSrc = GetDesktopWindow(); if (LockWindowUpdate(hwnd)) //锁定屏幕更新 { bCapturing = TRUE; SetCapture(hwnd); //鼠标捕获 SetCursor(LoadCursor(NULL, IDC_CROSS)); } else MessageBeep(0); } return 0; case WM_RBUTTONDOWN: if (bCapturing) { bBlocking = TRUE; ptBeg.x = LOWORD(lParam); //这里可以出现负坐标，从而导致截图不正常 ptBeg.y = HIWORD(lParam); ptEnd = ptBeg; InvertBlock(hwndSrc, hwnd, ptBeg, ptEnd); } return 0; case WM_MOUSEMOVE: if (bBlocking) { InvertBlock(hwndSrc, hwnd, ptBeg, ptEnd); ptEnd.x = LOWORD(lParam); ptEnd.y = HIWORD(lParam); InvertBlock(hwndSrc, hwnd, ptBeg, ptEnd); } return 0; case WM_LBUTTONUP: case WM_RBUTTONUP: if (bBlocking) { InvertBlock(hwndSrc, hwnd, ptBeg, ptEnd); ptEnd.x = LOWORD(lParam); //这里可以出现负坐标，从而导致截图不正常 ptEnd.y = HIWORD(lParam); if (hBitmap) { DeleteObject(hBitmap); hBitmap = NULL; } hdc = GetDC(NULL); //这里应获取桌面DC，书本这里有误 ClientToScreen(hwnd, &ptBeg); ClientToScreen(hwnd, &ptEnd); hdcMem = CreateCompatibleDC(hdc); hBitmap = CreateCompatibleBitmap(hdc, abs(ptEnd.x - ptBeg.x), abs(ptEnd.y - ptBeg.y)); SelectObject(hdcMem, hBitmap); StretchBlt(hdcMem, 0, 0, abs(ptEnd.x - ptBeg.x), abs(ptEnd.y - ptBeg.y), hdc, ptBeg.x, ptBeg.y, ptEnd.x - ptBeg.x, ptEnd.y - ptBeg.y, SRCCOPY); DeleteDC(hdcMem); DeleteDC(hdc); InvalidateRect(hwnd, NULL, TRUE); } if (bBlocking || bCapturing) { bBlocking = bCapturing = FALSE; SetCursor(LoadCursor(NULL, IDC_ARROW)); ReleaseCapture(); //释放鼠标捕获 LockWindowUpdate(NULL); //屏幕解锁 } return 0; case WM_PAINT: hdc = BeginPaint(hwnd, &ps); if (hBitmap) { GetClientRect(hwnd, &rect); hdcMem = CreateCompatibleDC(hdc); SelectObject(hdcMem, hBitmap); GetObject(hBitmap, sizeof(BITMAP), &bm); //该模式删除所有消除的像素行，不保留其信息 SetStretchBltMode(hdc, COLORONCOLOR); StretchBlt(hdc, 0, 0, rect.right, rect.bottom, hdcMem, 0, 0, bm.bmWidth, bm.bmHeight, SRCCOPY); DeleteDC(hdcMem); } EndPaint(hwnd, &ps); return 0; case WM_DESTROY: if (hBitmap) DeleteObject(hBitmap); PostQuitMessage(0); return 0; } return DefWindowProc(hwnd, message, wParam, lParam); }
//resource.h
//{{NO_DEPENDENCIES}} // Microsoft Visual C++ 生成的包含文件。 // 供 BlowUp.rc 使用 // #define IDM_EDIT_CUT 40001 #define IDM_EDIT_COPY 40002 #define IDM_EDIT_PASTE 40003 #define IDM_EDIT_CLEAR 40004 // Next default values for new objects // #ifdef APSTUDIO_INVOKED #ifndef APSTUDIO_READONLY_SYMBOLS #define _APS_NEXT_RESOURCE_VALUE 103 #define _APS_NEXT_COMMAND_VALUE 40010 #define _APS_NEXT_CONTROL_VALUE 1001 #define _APS_NEXT_SYMED_VALUE 101 #endif #endif
//BlowUp.rc
// Microsoft Visual C++ generated resource script. // #include "resource.h" #define APSTUDIO_READONLY_SYMBOLS ///////////////////////////////////////////////////////////////////////////// // // Generated from the TEXTINCLUDE 2 resource. // #include "winres.h" ///////////////////////////////////////////////////////////////////////////// #undef APSTUDIO_READONLY_SYMBOLS ///////////////////////////////////////////////////////////////////////////// // 中文(简体，中国) resources #if !defined(AFX_RESOURCE_DLL) || defined(AFX_TARG_CHS) LANGUAGE LANG_CHINESE, SUBLANG_CHINESE_SIMPLIFIED #ifdef APSTUDIO_INVOKED ///////////////////////////////////////////////////////////////////////////// // // TEXTINCLUDE // 1 TEXTINCLUDE BEGIN "resource.h " END 2 TEXTINCLUDE BEGIN "#include ""winres.h"" " " " END 3 TEXTINCLUDE BEGIN " " " " END #endif // APSTUDIO_INVOKED ///////////////////////////////////////////////////////////////////////////// // // Menu // BlowUp MENU BEGIN POPUP "&Edit" BEGIN MENUITEM "Cu&t Ctrl+X", 40001 MENUITEM "&Copy Ctrl+C", 40002 MENUITEM "&Paste Ctrl+V", 40003 MENUITEM "De&lete Delete", 40004 END END ///////////////////////////////////////////////////////////////////////////// // // Accelerator // BlowUp ACCELERATORS BEGIN "^C", IDM_EDIT_COPY, ASCII, NOINVERT "^V", IDM_EDIT_PASTE, ASCII, NOINVERT VK_DELETE, IDM_EDIT_CLEAR, VIRTKEY, NOINVERT "^X", IDM_EDIT_CUT, ASCII, NOINVERT END #endif // 中文(简体，中国) resources ///////////////////////////////////////////////////////////////////////////// #ifndef APSTUDIO_INVOKED ///////////////////////////////////////////////////////////////////////////// // // Generated from the TEXTINCLUDE 3 resource. // ///////////////////////////////////////////////////////////////////////////// #endif // not APSTUDIO_INVOKED