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The wmWindow struct is the abstraction of a separate standalone rectangular container of UI elements, usually framed by OS decoration like a title bar, and participates with other application windows on the user's desktop. Depending on the platform and use, it can close, minimize, resize, roll-up, etc.

Specifically, wmWindow holds all the data needed to save and recreate the window and all the data needed by Blender while it operates. This includes the operating system-supplied handle, parent, scene, layer, size, position, current cursor, event queue, handles, and more.

Getting the Current Window

It is a simple call to get the one current Window, which is the one that is active and in focus (currently receiving mouse and keyboard entry). How a window becomes active can vary by platform. On some operating systems you must click your mouse on the title bar or in the contents, and on others your mouse hovering over it might make it active.

In most cases you need a pointer to the window for a user-interactive purpose, so you can often avoid having to test the return for NULL. The exception to be aware of is when Blender is run headless from the command-line. You get the current window from the Context like this:

wmWindow *win = CTX_wm_window(C);

Enumerating All Windows

The list of windows is kept by the Window Manager. The following loops over all the windows:

wmWindowManager *wm = CTX_wm_manager(C);
LISTBASE_FOREACH (wmWindow *, win, &wm->windows) {

Temp Windows

It is the intention that the positions and sizes of windows are saved with the blend and restored when you load. However, we consider some windows to be "temporary". These include Preferences, File Manager, and Render Window, and these will not be restored when you load the file. You can find this status by calling WM_window_is_temp_screen(win)

Window Parenting

Window behavior should vary between platforms to provide expected behavior. Generally though our windows are parented to the window that created them. You can create a window that is top-level like the main window by using the toplevel argument of WM_window_open. For users, selecting Window / New Window will create a child, while Windows / New Main Window will create a top-level window that can create its own children. Having the two options allows many different ways of working with multiple windows.

Creating a New Window

The following will open a new window containing a 3D Viewport editor:

wmWindow *win = WM_window_open(
    C, "Title", 0, 0, 800, 600, SPACE_VIEW3D, false, false, false, WIN_ALIGN_ABSOLUTE);

Typical Window Operations

Once you have a pointer to a window, following are just some typical ways of operating on it:



For more specific information, look at these files: