andlabs-ui/area_windows.go

75 lines
1.5 KiB
Go

// 24 march 2014
package ui
import (
"fmt"
"syscall"
"unsafe"
"sync"
)
const (
areastyle = 0 | controlstyle
areaxstyle = 0 | controlxstyle
)
const (
areaWndClassFormat = "gouiarea%X"
)
var (
areaWndClassNum uintptr
areaWndClassNumLock sync.Mutex
)
func areaWndProc(s *sysData) func(hwnd _HWND, uMsg uint32, wParam _WPARAM, lParam _LPARAM) _LRESULT {
return func(hwnd _HWND, uMsg uint32, wParam _WPARAM, lParam _LPARAM) _LRESULT {
switch uMsg {
default:
r1, _, _ := defWindowProc.Call(
uintptr(hwnd),
uintptr(uMsg),
uintptr(wParam),
uintptr(lParam))
return _LRESULT(r1)
}
panic(fmt.Sprintf("areaWndProc message %d did not return: internal bug in ui library", uMsg))
}
}
func registerAreaWndClass(s *sysData) (newClassName string, err error) {
const (
// from winuser.h
_CS_DBLCLKS = 0x0008
)
areaWndClassNumLock.Lock()
newClassName = fmt.Sprintf(areaWndClassFormat, areaWndClassNum)
areaWndClassNum++
areaWndClassNumLock.Unlock()
wc := &_WNDCLASS{
style: _CS_DBLCLKS, // needed to be able to register double-clicks
lpszClassName: uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(newClassName))),
lpfnWndProc: syscall.NewCallback(areaWndProc(s)),
hInstance: hInstance,
hIcon: icon,
hCursor: cursor,
hbrBackground: _HBRUSH(_COLOR_BTNFACE + 1),
}
ret := make(chan uiret)
defer close(ret)
uitask <- &uimsg{
call: _registerClass,
p: []uintptr{uintptr(unsafe.Pointer(wc))},
ret: ret,
}
r := <-ret
if r.ret == 0 { // failure
return "", r.err
}
return newClassName, nil
}