func MustRegisterWindowClassWithWndProcPtr(className string, wndProcPtr uintptr) {
if registeredWindowClasses[className] {
panic("window class already registered")
}
hInst := win.GetModuleHandle(nil)
if hInst == 0 {
panic("GetModuleHandle")
}
hIcon := win.LoadIcon(0, (*uint16)(unsafe.Pointer(uintptr(win.IDI_APPLICATION))))
if hIcon == 0 {
panic("LoadIcon")
}
hCursor := win.LoadCursor(0, (*uint16)(unsafe.Pointer(uintptr(win.IDC_ARROW))))
if hCursor == 0 {
panic("LoadCursor")
}
var wc win.WNDCLASSEX
wc.CbSize = uint32(unsafe.Sizeof(wc))
wc.LpfnWndProc = wndProcPtr
wc.HInstance = hInst
wc.HIcon = hIcon
wc.HCursor = hCursor
wc.HbrBackground = win.COLOR_BTNFACE + 1
wc.LpszClassName = syscall.StringToUTF16Ptr(className)
if atom := win.RegisterClassEx(&wc); atom == 0 {
panic("RegisterClassEx")
}
registeredWindowClasses[className] = true
}
func NewIconFromResourceId(id uintptr) (*Icon, error) {
hInst := win.GetModuleHandle(nil)
if hInst == 0 {
return nil, lastError("GetModuleHandle")
}
hIcon := win.LoadIcon(hInst, win.MAKEINTRESOURCE(id))
if hIcon == 0 {
return nil, lastError("LoadIcon")
}
return &Icon{hIcon: hIcon}, nil
}
// NewIconFromResource returns a new Icon, using the specified icon resource.
func NewIconFromResource(resName string) (ic *Icon, err error) {
hInst := win.GetModuleHandle(nil)
if hInst == 0 {
err = lastError("GetModuleHandle")
return
}
if hIcon := win.LoadIcon(hInst, syscall.StringToUTF16Ptr(resName)); hIcon == 0 {
err = lastError("LoadIcon")
} else {
ic = &Icon{hIcon: hIcon}
}
return
}