在 Windows 上,当系统有多个监视器时,C/C++ 如何检测 WM_WINDOWPOSCHANGING 消息上的“最大化事件”?也就是说,当窗口在任何显示器上最大化时?
(也欢迎其他操作系统的代码!)
当窗口最大化时,特别是。作为交互式用户操作的结果,它接收WM_SYSCOMMAND
SC_MAXIMIZE
消息。
最大化过程通常涉及WM_GETMINMAXINFO
消息,处理...
应用程序可以使用此消息来覆盖窗口的默认最大化大小和位置,或者其默认的最小或最大跟踪大小。
要检测当前监视器工作区坐标,最简单的可能是MonitorFromRect
API:
HMONITOR hMonitor = MonitorFromRect(&rcCenter, MONITOR_DEFAULTTONEAREST);
if(hMonitor)
{
MONITORINFO MonitorInfo = { sizeof MonitorInfo };
GetMonitorInfo(hMonitor, &MonitorInfo);
// NOTE: MonitorInfo.rcWork is what you look for
首先,您需要使用EnumDisplayDevices和EnumDisplaySettingsEx检测所有显示器。
// C/C++ solution for enumerating display settings.
// Struct for display properties
struct DisplayProps
{
int x, y; // only display position is needed..
};
DISPLAY_DEVICE disp;
DISPLAY_DEVICE adapter;
DEVMODE mode;
DisplayProps the_displays[32]; // Array to store the results.
int i = 0, j = 0, display_count = 0;
// Initialize win32 structs.
memset(&disp, 0, sizeof(DISPLAY_DEVICE));
disp.cb = sizeof(DISPLAY_DEVICE);
memset(&args.adapter, 0, sizeof(DISPLAY_DEVICE));
adapter.cb = sizeof(DISPLAY_DEVICE);
memset(&mode, 0, sizeof(DEVMODE));
mode.dmSize = sizeof(DEVMODE);
memset(the_displays, 0, sizeof(the_displays));
// adapter loop:
while(EnumDisplayDevices(NULL, i, &adapter, 0))
{ // multiple displays on single adapter loop:
j = 0;
while(EnumDisplayDevices((TCHAR*)&adapter.DeviceName, j, &disp, 0))
{
// The device must be active, attached to desktop and not a mirroring device.
if((disp.StateFlags & DISPLAY_DEVICE_ACTIVE)
&& (disp.StateFlags & DISPLAY_DEVICE_ATTACHED_TO_DESKTOP)
&& !(disp.StateFlags & DISPLAY_DEVICE_MIRRORING_DRIVER))
{
// read display settings.
if(EnumDisplaySettingsEx((TCHAR*)&adapter.DeviceName, ENUM_CURRENT_SETTINGS, &mode, 0))
{
the_displays[display_count].x = mode.dmPosition.x;
the_displays[display_count].y = mode.dmPosition.y;
++display_count;
}
}
// Reset
memset(&args.disp, 0, sizeof(DISPLAY_DEVICE));
disp.cb = sizeof(DISPLAY_DEVICE);
++j;
}
// Reset
memset(&args.adapter, 0, sizeof(DISPLAY_DEVICE));
adapter.cb = sizeof(DISPLAY_DEVICE);
++i;
}
然后在窗口过程中的 WM_WINDOWPOSCHANGING 消息上,我们需要实际检测事件。这需要一个可能未记录的值 SWP_STATECHANGED (0x8000) 并使用AdjustWindowRectEx。
WINDOWPOS * wp = (WINDOWPOS*)lParam;
if( (wp->flags & (SWP_STATECHANGED | SWP_FRAMECHANGED)) != 0)
{
// Figuring next part was a bit of luck involved: I noticed that AdjustWindowRectEx rect.left
// matches window position (x and y) on default display when window is maximized
RECT styleadj = {0, 0, 0, 0};
// Can't cache/save this because user can change the theme.
AdjustWindowRectEx(&styleadj,
WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU | WS_MINIMIZEBOX, /* your window dwStyle */
false, /* not using menu? */
WS_EX_APPWINDOW | WS_EX_WINDOWEDGE); /* your window dwExStyle */
for(int i = 0; i < the_display_count; ++i)
{
if((wp->x == the_displays[i].x + styleadj.left) && (wp->y == the_displays[i].y + styleadj.left))
{
// Event is detected, do what ever you want!
MessageBox(NULL, "A Maximize event Detected.", "Event Detected!", MB_OK);
}
}
}
我已经确认此代码适用于多个显示器(我有两个)以及 Windows 7 Aero Glass 主题、Aero Basic 主题和旧 win 2000 主题。WinXp 和 8 未经测试。AdjustWindowRectEx确实在不同的主题上返回不同的值。