本部分讨论以下主题。
创建游标
以下示例创建两个游标句柄：一个用于标准沙漏游标，一个用于作为应用程序资源定义文件中的资源包含的自定义游标。
HCURSOR hCurs1 = LoadCursor(NULL, IDC_WAIT);
HCURSOR hCurs2 = LoadCursor(hInstance, MAKEINTRESOURCE(IDC_MYICON));
应用程序应实现自定义游标作为资源，并使用 LoadCursor、 LoadCursorFromFile 或 LoadImage ，而不是在运行时创建游标。 使用游标资源可避免设备依赖、简化本地化，并使应用程序能够共享游标设计。
以下示例使用 CreateCursor 函数在运行时创建自定义单色游标。 此处提供了该示例来说明系统如何解释游标掩码。
游标映射中的每个像素都由一个字符表示：
| 符号 | AND 位 | XOR 位 | 显示位置 |
|---|---|---|---|
|
1 | 0 | Transparent |
X |
1 | 1 | 反转屏幕 |
o |
0 | 1 | 白色 |
+ |
0 | 0 | 黑色 |
#define CURSOR_SIZE 32
// Symbol encoding: ' '=transparent 'o'=white '+'=black
static const char *const yin_cursor[CURSOR_SIZE] = {
" ++++ ",
" ++++oooo+ ",
" ++oooooo++ ",
" +ooooooo+ ",
" +oooooooo+ ",
" +oooooooo+ ",
" +oooooooo+ ",
" +oooooooo+ ",
" +ooooooooo+ ",
" +oooooooo+ ",
" +ooooooooo+ ",
" +ooooooooo+ ",
" +oooooooooo+ ",
"+ooooooooooo+ ",
"+oooooooooooo+ ",
"+ooooooooooooo++ ",
"+ooooooooooooooo+ ",
"+oooooooooooooooo++ ",
"+oooooooooooooooooo+ ",
" +ooooooooooooooooo+ ",
" +oooooooo+++ooooooo+ ",
" +ooooooo+++++oooooo+ ",
" +oooooo+++++oooooo+ ",
" +oooooo+++++ooooo+ ",
" +oooooo+++oooooo+ ",
" +ooooooooooooo+ ",
" +ooooooooooooo+ ",
" ++oooooooooo+ ",
" +oooooooo+ ",
" ++oooo++ ",
" ++++ ",
" ",
};
// Pack an XPM-style cursor map into separate 1bpp AND and XOR bit planes.
// Output buffers must be sized: ((w + 15) / 16) * 2 * h bytes.
static void PackCursorMasks(const char *const rows[], int w, int h,
BYTE *pbAnd, BYTE *pbXor)
{
int stride = ((w + 15) / 16) * 2; // WORD-aligned row stride, per CreateCursor contract
ZeroMemory(pbAnd, stride * h);
ZeroMemory(pbXor, stride * h);
for (int y = 0; y < h; y++) {
for (int x = 0; x < w; x++) {
BYTE bit = (BYTE)(0x80 >> (x % 8));
int idx = y * stride + x / 8;
char sym = rows[y][x];
if (sym == ' ' || sym == 'X') pbAnd[idx] |= bit;
if (sym == 'o' || sym == 'X') pbXor[idx] |= bit;
}
}
}
// Row stride for a 32-pixel-wide 1bpp mask: ((32 + 15) / 16) * 2 = 4 bytes.
BYTE abAnd[CURSOR_SIZE * 4];
BYTE abXor[CURSOR_SIZE * 4];
PackCursorMasks(yin_cursor, CURSOR_SIZE, CURSOR_SIZE, abAnd, abXor);
// hInstance is the application's HINSTANCE from WinMain.
// Call DestroyCursor when the cursor is no longer needed.
HCURSOR hCurs3 = CreateCursor(
hInstance, // application instance
19, // hot spot x
2, // hot spot y
CURSOR_SIZE,
CURSOR_SIZE,
abAnd,
abXor);
有关详细信息，请参阅位图。
使用游标函数创建捕鼠器
以下示例使用 SetCursorPos、GetCursorPos、CreateCursor、CreateIcon、SetCursor 和 DrawIconEx 函数来创建一个简单的鼠标陷阱。 在窗口中央绘制一个阳形图标。 如果光标 3 秒内未移动，它会自动吸附到阳图标并变为阴形状。 移动鼠标会重置陷阱。
// PackCursorMasks, yin_cursor, and CURSOR_SIZE are defined in the preceding example.
#define ICON_SIZE 32
#define YIN_HOT_X 19
#define YIN_HOT_Y 2
#define IDT_CURSOR 1
#define TRAP_DELAY 3000 // ms of inactivity before the cursor snaps to the icon
// Symbol encoding: ' '=transparent 'o'=white '+'=black
static const char *const yang_icon[ICON_SIZE] = {
" ",
" ++++ ",
" ++++++++ ",
" ++++++++++ ",
" +++++++++++++ ",
" +++++++++++++++ ",
" +++++++++++++++ ",
" ++++++ooo++++++++ ",
" +++++ooooo++++++++ ",
" ++++++ooooo++++++++ ",
" ++++++ooooo+++++++++ ",
" +++++++ooo++++++++++ ",
" +++++++++++++++++++ ",
" ++++++++++++++++++++",
" +++++++++++++++++++",
" ++++++++++++++++++",
" ++++++++++++++++",
" +++++++++++++++",
" +++++++++++++",
" ++++++++++++ ",
" +++++++++++ ",
" +++++++++++ ",
" ++++++++++ ",
" +++++++++++ ",
" ++++++++++ ",
" ++++++++++ ",
" ++++++++++ ",
" ++++++++++ ",
" +++++++++ ",
" ++++++++++ ",
" +++++++++ ",
" ++++ ",
};
static HICON hYang;
static HCURSOR hYin;
static POINT ptLast;
static BOOL bTrapped;
LRESULT CALLBACK MainWndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
case WM_CREATE:
{
HINSTANCE hInstance = ((LPCREATESTRUCT)lParam)->hInstance;
BYTE abAndIcon[ICON_SIZE * 4];
BYTE abXorIcon[ICON_SIZE * 4];
PackCursorMasks(yang_icon, ICON_SIZE, ICON_SIZE, abAndIcon, abXorIcon);
hYang = CreateIcon(hInstance, ICON_SIZE, ICON_SIZE, 1, 1,
abAndIcon, abXorIcon);
BYTE abAndCursor[CURSOR_SIZE * 4];
BYTE abXorCursor[CURSOR_SIZE * 4];
PackCursorMasks(yin_cursor, CURSOR_SIZE, CURSOR_SIZE, abAndCursor, abXorCursor);
hYin = CreateCursor(hInstance, YIN_HOT_X, YIN_HOT_Y, CURSOR_SIZE, CURSOR_SIZE,
abAndCursor, abXorCursor);
GetCursorPos(&ptLast);
SetTimer(hWnd, IDT_CURSOR, TRAP_DELAY, (TIMERPROC)NULL);
return 0;
}
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hDC = BeginPaint(hWnd, &ps);
RECT rc;
GetClientRect(hWnd, &rc);
DrawIconEx(hDC,
(rc.right - ICON_SIZE) / 2,
(rc.bottom - ICON_SIZE) / 2,
hYang, ICON_SIZE, ICON_SIZE, 0, NULL, DI_NORMAL);
EndPaint(hWnd, &ps);
return 0;
}
case WM_MOUSEMOVE:
{
POINT ptNow;
GetCursorPos(&ptNow);
if (ptNow.x != ptLast.x || ptNow.y != ptLast.y)
{
ptLast = ptNow;
bTrapped = FALSE;
SetTimer(hWnd, IDT_CURSOR, TRAP_DELAY, (TIMERPROC)NULL);
}
break;
}
case WM_TIMER:
{
POINT ptNow;
GetCursorPos(&ptNow);
if (ptNow.x == ptLast.x && ptNow.y == ptLast.y)
{
RECT rc;
GetClientRect(hWnd, &rc);
POINT ptTarget = {
(rc.right - ICON_SIZE) / 2 + YIN_HOT_X,
(rc.bottom - ICON_SIZE) / 2 + YIN_HOT_Y
};
ClientToScreen(hWnd, &ptTarget);
SetCursorPos(ptTarget.x, ptTarget.y);
// Ignore the mouse-move notification generated by this repositioning.
GetCursorPos(&ptLast);
SetCursor(hYin);
bTrapped = TRUE;
KillTimer(hWnd, IDT_CURSOR);
}
else
{
// Movement outside this window does not generate WM_MOUSEMOVE here.
ptLast = ptNow;
}
return 0;
}
case WM_SETCURSOR:
if (bTrapped)
{
SetCursor(hYin);
return TRUE;
}
break;
case WM_DESTROY:
KillTimer(hWnd, IDT_CURSOR);
DestroyCursor(hYin);
DestroyIcon(hYang);
PostQuitMessage(0);
return 0;
}
return DefWindowProc(hWnd, uMsg, wParam, lParam);
}
创建 Alpha 混合光标
按照以下步骤在运行时创建 alpha 混合光标或图标：
- 为自上而下的 DIB 填充
biCompression=BI_RGB（biHeight、、 为负），并调用 CreateDIBSection 以获取颜色位图。 重复使用同一标头biBitCount=1来创建 1bpp AND 掩码。 - 将光标图像绘制到颜色 DIB 节中，并设置每个像素的 Alpha 字节。
- 填充 AND 掩码：将每个位在
alpha > 0处设为 0（不透明），在alpha == 0处设为 1（透明）。 - 用作为 的 DIB 节和作为 的 AND 掩码填充
hbmMask结构。 - 调用 CreateIconIndirect 创建游标或图标。
以下代码演示如何创建 alpha 混合游标。
DrawRGBCircles将三个重叠的 R/G/B 半透明圆直接写入像素缓冲区：它使用 AC_SRC_OVER 公式以解析方式合成这些圆，并将预乘的 RGB 通道与 alpha 一起存储在 rgbReserved 中。 从 GetSystemMetrics 读取游标大小以匹配系统游标大小设置。 将 TRUE 更改为 fIcon，以创建图标。
#define WIDTHBYTES(bits) ((DWORD)(((bits) + 31) & ~31) / 8)
// Fill pixels (top-down, cx-cy) with three overlapping R/G/B circles, each alpha=128.
// Composites with AC_SRC_OVER and preserves premultiplied RGB channels.
static void DrawRGBCircles(RGBQUAD *pixels, int cx, int cy)
{
// r = cx/3: each center is r px from its nearest edge, so the circle touches exactly.
const int r = cx / 3;
struct { int x, y; RGBQUAD color; } circles[3] = {
// B G R A
{ cx / 2, r, { 0, 0, 255, 128 } }, // red, top-center
{ r, cy - r, { 0, 255, 0, 128 } }, // green, bottom-left
{ cx - r, cy - r, {255, 0, 0, 128 } }, // blue, bottom-right
};
for (int y = 0; y < cy; y++) {
for (int x = 0; x < cx; x++) {
DWORD R = 0, G = 0, B = 0, A = 0;
for (int i = 0; i < 3; i++) {
int dx = x - circles[i].x, dy = y - circles[i].y;
if (dx*dx + dy*dy > r*r) continue;
DWORD a = circles[i].color.rgbReserved, inv = 255 - a;
// AC_SRC_OVER (premultiplied): dst = src + dst * (1 - src_a/255)
R = circles[i].color.rgbRed * a / 255 + R * inv / 255;
G = circles[i].color.rgbGreen * a / 255 + G * inv / 255;
B = circles[i].color.rgbBlue * a / 255 + B * inv / 255;
A = a + A * inv / 255;
}
RGBQUAD *p = &pixels[y * cx + x];
p->rgbReserved = (BYTE)A;
p->rgbRed = (BYTE)R;
p->rgbGreen = (BYTE)G;
p->rgbBlue = (BYTE)B;
}
}
}
HCURSOR CreateAlphaCursor(void)
{
int cx = GetSystemMetrics(SM_CXCURSOR);
int cy = GetSystemMetrics(SM_CYCURSOR);
// Extra RGBQUAD at the end for the 1bpp colour table (index 1 = white).
BYTE bmiBuffer[sizeof(BITMAPINFO) + sizeof(RGBQUAD)] = {0};
BITMAPINFO *pBmi = (BITMAPINFO *)bmiBuffer;
pBmi->bmiHeader.biSize = sizeof(pBmi->bmiHeader);
pBmi->bmiHeader.biWidth = cx;
pBmi->bmiHeader.biHeight = -cy; // negative = top-down
pBmi->bmiHeader.biPlanes = 1;
pBmi->bmiHeader.biCompression = BI_RGB;
// Create a top-down 32bpp DIB section for the color (XOR) image.
pBmi->bmiHeader.biBitCount = 32;
RGBQUAD *lpBits;
HBITMAP hBitmap = CreateDIBSection(NULL, pBmi, DIB_RGB_COLORS, (void **)&lpBits, NULL, 0);
DrawRGBCircles(lpBits, cx, cy);
// Reuse the same header for the 1bpp AND mask; switch biBitCount and set the colour table.
pBmi->bmiHeader.biBitCount = 1;
pBmi->bmiColors[0].rgbRed = pBmi->bmiColors[0].rgbGreen = pBmi->bmiColors[0].rgbBlue = 0;
pBmi->bmiColors[1].rgbRed = pBmi->bmiColors[1].rgbGreen = pBmi->bmiColors[1].rgbBlue = 255;
BYTE *andBits;
HBITMAP hMaskBitmap = CreateDIBSection(NULL, pBmi, DIB_RGB_COLORS, (void **)&andBits, NULL, 0);
// Set AND mask: bit=1 (transparent) wherever no circle was drawn.
int maskStride = WIDTHBYTES(cx * 1);
for (int y = 0; y < cy; y++) {
for (int x = 0; x < cx; x++) {
if (lpBits[y * cx + x].rgbReserved == 0)
andBits[y * maskStride + x / 8] |= (BYTE)(0x80 >> (x % 8));
}
}
ICONINFO ii = {0};
ii.fIcon = FALSE;
ii.xHotspot = cx / 2;
ii.yHotspot = cy / 2;
ii.hbmMask = hMaskBitmap;
ii.hbmColor = hBitmap;
HCURSOR hCursor = (HCURSOR)CreateIconIndirect(&ii);
DeleteObject(hBitmap);
DeleteObject(hMaskBitmap);
return hCursor;
}
在关闭之前，必须使用 DestroyCursor 函数销毁使用 CreateCursor 或 CreateIconIndirect 创建的任何游标。 不需要销毁由其他函数创建的游标。
获取光标大小
以下示例从光标或图标的句柄中检索其维度：
BOOL GetCursorDimensions(_In_ HCURSOR hcur, _Out_ SIZE *psiz)
{
ICONINFO ii;
BOOL fResult = GetIconInfo(hcur, &ii);
if (fResult) {
BITMAP bm;
fResult = GetObject(ii.hbmMask, sizeof(bm), &bm) == sizeof(bm);
if (fResult) {
psiz->cx = bm.bmWidth;
psiz->cy = ii.hbmColor ? bm.bmHeight : bm.bmHeight / 2;
}
DeleteObject(ii.hbmMask);
if (ii.hbmColor) DeleteObject(ii.hbmColor);
}
return fResult;
}
显示光标
系统会自动显示类游标（与光标指向的窗口关联的游标）。 注册窗口类时，可以分配类游标。 以下示例通过将游标句柄分配给由 wc 参数标识的 WNDCLASS 结构的 hCursor 成员来说明这一点。
WNDCLASS wc = {0};
wc.lpfnWndProc = MainWndProc;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(hInstance, MAKEINTRESOURCE(IDC_MYICON));
wc.hbrBackground = GetStockObject(WHITE_BRUSH);
wc.lpszMenuName = TEXT("GenericMenu");
wc.lpszClassName = TEXT("GenericWClass");
return RegisterClass(&wc);
注册窗口类时，应用程序资源定义文件中标识 IDC_MYICON 的游标是基于该类的所有窗口的默认游标。
应用程序可以使用 SetCursor 函数和指定不同的游标句柄来更改游标的设计。 但是，当游标移动时，系统会在新位置重新绘制类游标。 若要防止重新绘制类游标，必须处理 WM_SETCURSOR 消息。 每次未捕获光标移动和鼠标输入时，系统都会将此消息发送到光标移动的窗口。
可以在处理 WM_SETCURSOR时为不同的条件指定不同的游标。 检查 LOWORD(lParam) 以区分工作区与非客户端区域，例如调整句柄的大小;将非客户端命中传递给 DefWindowProc ，以便系统在此处设置相应的系统游标。
case WM_SETCURSOR:
if (LOWORD(lParam) == HTCLIENT)
{
SetCursor(hCurs3);
return TRUE;
}
return DefWindowProc(hWnd, uMsg, wParam, lParam);
TRUE返回可防止 DefWindowProc 将游标重置为类游标。 将非客户端区域命中交给 DefWindowProc 处理，可保留系统调整大小和移动光标。
可以使用 SetClassLongPtr 函数替换类游标。 此函数更改指定类的所有窗口的默认窗口设置。 以下示例将现有类游标替换为 hCurs2 游标。
SetClassLongPtr(hWnd, GCLP_HCURSOR, (LONG_PTR)hCurs2);
限制光标
以下示例将光标限制为应用程序的窗口，然后将光标还原到其上一个窗口。 该示例使用 GetClipCursor 函数来记录游标可移动的区域以及 ClipCursor 函数来限制和还原游标。
RECT rcOldClip;
GetClipCursor(&rcOldClip);
RECT rcClip;
GetWindowRect(hWnd, &rcClip);
ClipCursor(&rcClip);
// ... process input from the confined cursor ...
ClipCursor(&rcOldClip);
由于系统一次只能使用一个光标，因此将光标限制在特定区域内的应用程序必须先恢复光标，然后才能将控制权交给另一个窗口。
使用键盘移动光标
由于系统不需要鼠标，因此应用程序应能够使用键盘模拟鼠标作。 以下示例演示如何通过使用 GetCursorPos 和 SetCursorPos 函数以及处理箭头键的输入来实现此目的。
static int nRepeat = 1;
switch (uMsg)
{
case WM_KEYDOWN:
{
int dx = 0, dy = 0;
switch (wParam)
{
case VK_LEFT: dx = -nRepeat; break;
case VK_RIGHT: dx = +nRepeat; break;
case VK_UP: dy = -nRepeat; break;
case VK_DOWN: dy = +nRepeat; break;
default: return DefWindowProc(hWnd, uMsg, wParam, lParam);
}
POINT pt;
GetCursorPos(&pt);
ScreenToClient(hWnd, &pt);
pt.x += dx;
pt.y += dy;
RECT rc;
GetClientRect(hWnd, &rc);
if (pt.x < rc.left) pt.x = rc.left;
else if (pt.x >= rc.right) pt.x = rc.right - 1;
if (pt.y < rc.top) pt.y = rc.top;
else if (pt.y >= rc.bottom) pt.y = rc.bottom - 1;
ClientToScreen(hWnd, &pt);
SetCursorPos(pt.x, pt.y);
if (nRepeat < 32) nRepeat++;
return 0;
}
case WM_KEYUP:
nRepeat = 1;
return 0;
}