deft.platform.win32.init source code

1 /**
2  * Process-wide Win32 initialization: the module handle and the default window
3  * class registration.
4  */
5 module deft.platform.win32.init;
6 
7 version (Windows):
8 
9 import core.sys.windows.windows;
10 
11 import deft.platform.win32.wndproc : wndProc;
12 
13 /// The name of Deft's default top-level window class (null-terminated literal).
14 enum deftWindowClassName = "DeftWindow"w;
15 
16 private __gshared HINSTANCE g_hInstance;
17 private __gshared bool g_classRegistered;
18 
19 /// The process module handle, fetched lazily via `GetModuleHandleW(null)`.
20 HINSTANCE hInstance()
21 {
22 	if (g_hInstance is null)
23 		g_hInstance = GetModuleHandleW(null);
24 	return g_hInstance;
25 }
26 
27 /**
28  * Register the default window class on first use. Idempotent.
29  *
30  * The class uses the master `wndProc`, redraws on resize (`CS_HREDRAW |
31  * CS_VREDRAW`), the standard arrow cursor and the system window background.
32  */
33 void ensureWindowClass()
34 {
35 	if (g_classRegistered)
36 		return;
37 	g_classRegistered = true;
38 
39 	// Default the window icon to the executable's first icon resource (id 1, the
40 	// conventional application-icon id), so an app that embeds an .ico via its .rc
41 	// gets it in the title bar/taskbar/Alt+Tab with no extra code. Apps can still
42 	// override per-window with Window.setIcon. Null when no icon resource exists.
43 	HICON appIcon = LoadIconW(hInstance(), cast(LPCWSTR) cast(void*) cast(size_t) 1);
44 
45 	WNDCLASSEXW wc;
46 	wc.cbSize = WNDCLASSEXW.sizeof;
47 	wc.style = CS_HREDRAW | CS_VREDRAW;
48 	wc.lpfnWndProc = &wndProc;
49 	wc.cbClsExtra = 0;
50 	wc.cbWndExtra = 0;
51 	wc.hInstance = hInstance();
52 	wc.hIcon = appIcon;
53 	wc.hCursor = LoadCursorW(null, IDC_ARROW);
54 	wc.hbrBackground = cast(HBRUSH)(COLOR_WINDOW + 1);
55 	wc.lpszMenuName = null;
56 	wc.lpszClassName = deftWindowClassName.ptr;
57 	wc.hIconSm = appIcon;
58 
59 	RegisterClassExW(&wc);
60 }