C语言 避免在两个屏幕之间打开窗口

Question

我正在为Windows编写一个Photoshop插件，并希望将插件对话框放在主窗口的中心。

这是我的代码:

void centre_window(HWND hwnd){
RECT rs, rd;
HWND hw = GetParent(hwnd); // GetDesktopWindow();
if (GetWindowRect(hw, &rs) && GetWindowRect(hwnd, &rd))
MoveWindow(hwnd,(rs.right + rs.left + rd.left - rd.right) / 2,
(rs.bottom + rs.top + rd.top - rd.bottom) / 3,
rd.right - rd.left, rd.bottom - rd.top, TRUE);
}

到目前为止，它是有效的。但是有一个缺陷:如果主窗口分布在两个屏幕上，那么我的窗口就在两个屏幕之间。

我看了其他Photoshop插件，他们是这样处理的:

1. 将窗口放置在主窗口中心
2. 如果它将在两个屏幕之间，选择其中一个并将其放置在屏幕的边界

我该怎么做呢?

Answer 1

在@IInspectable的帮助下，我编写了以下代码:

void _doMonitorAdjustments(LPRECT rcPlugin) {
RECT rcMonitorWork;
HMONITOR hMonitor;
MONITORINFO grMonitorInfo = { sizeof(grMonitorInfo) };
int nXAdjust = 0, nYAdjust = 0, nPluginWidth, nPluginHeight, nMonitorWorkWidth, nMonitorWorkHeight;
hMonitor = MonitorFromRect(rcPlugin, MONITOR_DEFAULTTONEAREST);
if (hMonitor == NULL) return;
if (!GetMonitorInfoA(hMonitor, &grMonitorInfo)) return;
rcMonitorWork = grMonitorInfo.rcWork;
// Don't let the window exit the left/right borders of the monitor
nPluginWidth = rcPlugin->right - rcPlugin->left;
nMonitorWorkWidth = rcMonitorWork.right - rcMonitorWork.left;
if (nPluginWidth > nMonitorWorkWidth) {
// Window larger than screen width. Decrease the width!
rcPlugin->left = rcMonitorWork.left;
rcPlugin->right = rcMonitorWork.right;
}
else if (rcPlugin->left < rcMonitorWork.left) {
nXAdjust = rcMonitorWork.left - rcPlugin->left;
}
else if (rcPlugin->right > rcMonitorWork.right) {
nXAdjust = rcMonitorWork.right  - rcPlugin->right;
}
// Don't let the window exit the top/bottom borders of the monitor
nPluginHeight = rcPlugin->bottom - rcPlugin->top;
nMonitorWorkHeight = rcMonitorWork.bottom - rcMonitorWork.top;
if (nPluginHeight > nMonitorWorkHeight) {
// Window larger than screen height. Decrease the height!
rcPlugin->top = rcMonitorWork.top;
rcPlugin->bottom = rcMonitorWork.bottom;
}
else if (rcPlugin->top < rcMonitorWork.top) {
nYAdjust = rcMonitorWork.top - rcPlugin->top;
}
else if (rcPlugin->bottom > rcMonitorWork.bottom) {
nYAdjust = rcMonitorWork.bottom - rcPlugin->bottom;
}
OffsetRect(rcPlugin, nXAdjust, nYAdjust);
}
/*
* Centers a window to the center of its parent form but avoids
* being spread across two screens.
*/
void centre_window(HWND hwnd) {
RECT rcParent, rcWindowOriginal, rcPlugin;
HWND hParent;

hParent = GetParent(hwnd);
if (hParent == NULL) hParent = GetDesktopWindow();
if (!GetWindowRect(hParent, &rcParent)) return;
if (!GetWindowRect(hwnd, &rcWindowOriginal)) return;
rcPlugin.left =
rcParent.left
+ (rcParent.right - rcParent.left) / 2
- (rcWindowOriginal.right - rcWindowOriginal.left) / 2;
rcPlugin.top =
rcParent.top
+ (rcParent.bottom - rcParent.top) / 2
- (rcWindowOriginal.bottom - rcWindowOriginal.top) / 2;
rcPlugin.right =
rcPlugin.left + rcWindowOriginal.right - rcWindowOriginal.left;
rcPlugin.bottom =
rcPlugin.top + rcWindowOriginal.bottom - rcWindowOriginal.top;
// Avoid that the window is spread across two screens
_doMonitorAdjustments(&rcPlugin);
MoveWindow(hwnd,
rcPlugin.left,
rcPlugin.top,
/*width=*/rcPlugin.right - rcPlugin.left,
/*height=*/rcPlugin.bottom - rcPlugin.top,
TRUE);
}