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// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build windows
// Package win32 implements a partial shiny screen driver using the Win32 API.
// It provides window, lifecycle, key, and mouse management, but no drawing.
// That is left to windriver (using GDI) or gldriver (using DirectX via ANGLE).
package win32 // import "golang.org/x/exp/shiny/driver/internal/win32"
import (
"fmt"
"runtime"
"sync"
"syscall"
"unsafe"
"golang.org/x/exp/shiny/screen"
"golang.org/x/mobile/event/key"
"golang.org/x/mobile/event/lifecycle"
"golang.org/x/mobile/event/mouse"
"golang.org/x/mobile/event/paint"
"golang.org/x/mobile/event/size"
"golang.org/x/mobile/geom"
)
// screenHWND is the handle to the "Screen window".
// The Screen window encapsulates all screen.Screen operations
// in an actual Windows window so they all run on the main thread.
// Since any messages sent to a window will be executed on the
// main thread, we can safely use the messages below.
var screenHWND syscall.Handle
const (
msgCreateWindow = _WM_USER + iota
msgMainCallback
msgShow
msgQuit
msgLast
)
// userWM is used to generate private (WM_USER and above) window message IDs
// for use by screenWindowWndProc and windowWndProc.
type userWM struct {
sync.Mutex
id uint32
}
func (m *userWM) next() uint32 {
m.Lock()
if m.id == 0 {
m.id = msgLast
}
r := m.id
m.id++
m.Unlock()
return r
}
var currentUserWM userWM
func newWindow(opts *screen.NewWindowOptions) (syscall.Handle, error) {
// TODO(brainman): convert windowClass to *uint16 once (in initWindowClass)
wcname, err := syscall.UTF16PtrFromString(windowClass)
if err != nil {
return 0, err
}
title, err := syscall.UTF16PtrFromString(opts.GetTitle())
if err != nil {
return 0, err
}
hwnd, err := _CreateWindowEx(0,
wcname, title,
_WS_OVERLAPPEDWINDOW,
_CW_USEDEFAULT, _CW_USEDEFAULT,
_CW_USEDEFAULT, _CW_USEDEFAULT,
0, 0, hThisInstance, 0)
if err != nil {
return 0, err
}
// TODO(andlabs): use proper nCmdShow
// TODO(andlabs): call UpdateWindow()
return hwnd, nil
}
// ResizeClientRect makes hwnd client rectangle opts.Width by opts.Height in size.
func ResizeClientRect(hwnd syscall.Handle, opts *screen.NewWindowOptions) error {
if opts == nil || opts.Width <= 0 || opts.Height <= 0 {
return nil
}
var cr, wr _RECT
err := _GetClientRect(hwnd, &cr)
if err != nil {
return err
}
err = _GetWindowRect(hwnd, &wr)
if err != nil {
return err
}
w := (wr.Right - wr.Left) - (cr.Right - int32(opts.Width))
h := (wr.Bottom - wr.Top) - (cr.Bottom - int32(opts.Height))
return _MoveWindow(hwnd, wr.Left, wr.Top, w, h, false)
}
// Show shows a newly created window.
// It sends the appropriate lifecycle events, makes the window appear
// on the screen, and sends an initial size event.
//
// This is a separate step from NewWindow to give the driver a chance
// to setup its internal state for a window before events start being
// delivered.
func Show(hwnd syscall.Handle) {
SendMessage(hwnd, msgShow, 0, 0)
}
func Release(hwnd syscall.Handle) {
SendMessage(hwnd, _WM_CLOSE, 0, 0)
}
func sendFocus(hwnd syscall.Handle, uMsg uint32, wParam, lParam uintptr) (lResult uintptr) {
switch uMsg {
case _WM_SETFOCUS:
LifecycleEvent(hwnd, lifecycle.StageFocused)
case _WM_KILLFOCUS:
LifecycleEvent(hwnd, lifecycle.StageVisible)
default:
panic(fmt.Sprintf("unexpected focus message: %d", uMsg))
}
return _DefWindowProc(hwnd, uMsg, wParam, lParam)
}
func sendShow(hwnd syscall.Handle, uMsg uint32, wParam, lParam uintptr) (lResult uintptr) {
LifecycleEvent(hwnd, lifecycle.StageVisible)
_ShowWindow(hwnd, _SW_SHOWDEFAULT)
sendSize(hwnd)
return 0
}
func sendSizeEvent(hwnd syscall.Handle, uMsg uint32, wParam, lParam uintptr) (lResult uintptr) {
wp := (*_WINDOWPOS)(unsafe.Pointer(lParam))
if wp.Flags&_SWP_NOSIZE != 0 {
return 0
}
sendSize(hwnd)
return 0
}
func sendSize(hwnd syscall.Handle) {
var r _RECT
if err := _GetClientRect(hwnd, &r); err != nil {
panic(err) // TODO(andlabs)
}
width := int(r.Right - r.Left)
height := int(r.Bottom - r.Top)
// TODO(andlabs): don't assume that PixelsPerPt == 1
SizeEvent(hwnd, size.Event{
WidthPx: width,
HeightPx: height,
WidthPt: geom.Pt(width),
HeightPt: geom.Pt(height),
PixelsPerPt: 1,
})
}
func sendClose(hwnd syscall.Handle, uMsg uint32, wParam, lParam uintptr) (lResult uintptr) {
// TODO(ktye): DefWindowProc calls DestroyWindow by default.
// To intercept destruction of the window, return 0 and call
// DestroyWindow when appropriate.
LifecycleEvent(hwnd, lifecycle.StageDead)
return _DefWindowProc(hwnd, uMsg, wParam, lParam)
}
func sendMouseEvent(hwnd syscall.Handle, uMsg uint32, wParam, lParam uintptr) (lResult uintptr) {
e := mouse.Event{
X: float32(_GET_X_LPARAM(lParam)),
Y: float32(_GET_Y_LPARAM(lParam)),
Modifiers: keyModifiers(),
}
switch uMsg {
case _WM_MOUSEMOVE:
e.Direction = mouse.DirNone
case _WM_LBUTTONDOWN, _WM_MBUTTONDOWN, _WM_RBUTTONDOWN:
e.Direction = mouse.DirPress
case _WM_LBUTTONUP, _WM_MBUTTONUP, _WM_RBUTTONUP:
e.Direction = mouse.DirRelease
case _WM_MOUSEWHEEL:
// TODO: On a trackpad, a scroll can be a drawn-out affair with a
// distinct beginning and end. Should the intermediate events be
// DirNone?
e.Direction = mouse.DirStep
// Convert from screen to window coordinates.
p := _POINT{
int32(e.X),
int32(e.Y),
}
_ScreenToClient(hwnd, &p)
e.X = float32(p.X)
e.Y = float32(p.Y)
default:
panic("sendMouseEvent() called on non-mouse message")
}
switch uMsg {
case _WM_MOUSEMOVE:
// No-op.
case _WM_LBUTTONDOWN, _WM_LBUTTONUP:
e.Button = mouse.ButtonLeft
case _WM_MBUTTONDOWN, _WM_MBUTTONUP:
e.Button = mouse.ButtonMiddle
case _WM_RBUTTONDOWN, _WM_RBUTTONUP:
e.Button = mouse.ButtonRight
case _WM_MOUSEWHEEL:
// TODO: handle horizontal scrolling
delta := _GET_WHEEL_DELTA_WPARAM(wParam) / _WHEEL_DELTA
switch {
case delta > 0:
e.Button = mouse.ButtonWheelUp
case delta < 0:
e.Button = mouse.ButtonWheelDown
delta = -delta
default:
return
}
for delta > 0 {
MouseEvent(hwnd, e)
delta--
}
return
}
MouseEvent(hwnd, e)
return 0
}
// Precondition: this is called in immediate response to the message that triggered the event (so not after w.Send).
func keyModifiers() (m key.Modifiers) {
down := func(x int32) bool {
// GetKeyState gets the key state at the time of the message, so this is what we want.
return _GetKeyState(x)&0x80 != 0
}
if down(_VK_CONTROL) {
m |= key.ModControl
}
if down(_VK_MENU) {
m |= key.ModAlt
}
if down(_VK_SHIFT) {
m |= key.ModShift
}
if down(_VK_LWIN) || down(_VK_RWIN) {
m |= key.ModMeta
}
return m
}
var (
MouseEvent func(hwnd syscall.Handle, e mouse.Event)
PaintEvent func(hwnd syscall.Handle, e paint.Event)
SizeEvent func(hwnd syscall.Handle, e size.Event)
KeyEvent func(hwnd syscall.Handle, e key.Event)
LifecycleEvent func(hwnd syscall.Handle, e lifecycle.Stage)
// TODO: use the golang.org/x/exp/shiny/driver/internal/lifecycler package
// instead of or together with the LifecycleEvent callback?
)
func sendPaint(hwnd syscall.Handle, uMsg uint32, wParam, lParam uintptr) (lResult uintptr) {
PaintEvent(hwnd, paint.Event{})
return _DefWindowProc(hwnd, uMsg, wParam, lParam)
}
var screenMsgs = map[uint32]func(hwnd syscall.Handle, uMsg uint32, wParam, lParam uintptr) (lResult uintptr){}
func AddScreenMsg(fn func(hwnd syscall.Handle, uMsg uint32, wParam, lParam uintptr)) uint32 {
uMsg := currentUserWM.next()
screenMsgs[uMsg] = func(hwnd syscall.Handle, uMsg uint32, wParam, lParam uintptr) uintptr {
fn(hwnd, uMsg, wParam, lParam)
return 0
}
return uMsg
}
func screenWindowWndProc(hwnd syscall.Handle, uMsg uint32, wParam uintptr, lParam uintptr) (lResult uintptr) {
switch uMsg {
case msgCreateWindow:
p := (*newWindowParams)(unsafe.Pointer(lParam))
p.w, p.err = newWindow(p.opts)
case msgMainCallback:
go func() {
mainCallback()
SendScreenMessage(msgQuit, 0, 0)
}()
case msgQuit:
_PostQuitMessage(0)
}
fn := screenMsgs[uMsg]
if fn != nil {
return fn(hwnd, uMsg, wParam, lParam)
}
return _DefWindowProc(hwnd, uMsg, wParam, lParam)
}
//go:uintptrescapes
func SendScreenMessage(uMsg uint32, wParam uintptr, lParam uintptr) (lResult uintptr) {
return SendMessage(screenHWND, uMsg, wParam, lParam)
}
var windowMsgs = map[uint32]func(hwnd syscall.Handle, uMsg uint32, wParam, lParam uintptr) (lResult uintptr){
_WM_SETFOCUS: sendFocus,
_WM_KILLFOCUS: sendFocus,
_WM_PAINT: sendPaint,
msgShow: sendShow,
_WM_WINDOWPOSCHANGED: sendSizeEvent,
_WM_CLOSE: sendClose,
_WM_LBUTTONDOWN: sendMouseEvent,
_WM_LBUTTONUP: sendMouseEvent,
_WM_MBUTTONDOWN: sendMouseEvent,
_WM_MBUTTONUP: sendMouseEvent,
_WM_RBUTTONDOWN: sendMouseEvent,
_WM_RBUTTONUP: sendMouseEvent,
_WM_MOUSEMOVE: sendMouseEvent,
_WM_MOUSEWHEEL: sendMouseEvent,
_WM_KEYDOWN: sendKeyEvent,
_WM_KEYUP: sendKeyEvent,
// TODO case _WM_SYSKEYDOWN, _WM_SYSKEYUP:
}
func AddWindowMsg(fn func(hwnd syscall.Handle, uMsg uint32, wParam, lParam uintptr)) uint32 {
uMsg := currentUserWM.next()
windowMsgs[uMsg] = func(hwnd syscall.Handle, uMsg uint32, wParam, lParam uintptr) uintptr {
fn(hwnd, uMsg, wParam, lParam)
return 0
}
return uMsg
}
func windowWndProc(hwnd syscall.Handle, uMsg uint32, wParam uintptr, lParam uintptr) (lResult uintptr) {
fn := windowMsgs[uMsg]
if fn != nil {
return fn(hwnd, uMsg, wParam, lParam)
}
return _DefWindowProc(hwnd, uMsg, wParam, lParam)
}
type newWindowParams struct {
opts *screen.NewWindowOptions
w syscall.Handle
err error
}
func NewWindow(opts *screen.NewWindowOptions) (syscall.Handle, error) {
var p newWindowParams
p.opts = opts
SendScreenMessage(msgCreateWindow, 0, uintptr(unsafe.Pointer(&p)))
return p.w, p.err
}
const windowClass = "shiny_Window"
const screenWindowClass = "shiny_ScreenWindow"
func initWindowClass() (err error) {
wcname, err := syscall.UTF16PtrFromString(windowClass)
if err != nil {
return err
}
_, err = _RegisterClass(&_WNDCLASS{
LpszClassName: wcname,
LpfnWndProc: syscall.NewCallback(windowWndProc),
HIcon: hDefaultIcon,
HCursor: hDefaultCursor,
HInstance: hThisInstance,
// TODO(andlabs): change this to something else? NULL? the hollow brush?
HbrBackground: syscall.Handle(_COLOR_BTNFACE + 1),
})
return err
}
func closeWindowClass() (err error) {
wcname, err := syscall.UTF16PtrFromString(windowClass)
if err != nil {
return err
}
_UnregisterClass(wcname, hThisInstance)
return nil
}
func initScreenWindow() (err error) {
swc, err := syscall.UTF16PtrFromString(screenWindowClass)
if err != nil {
return err
}
emptyString, err := syscall.UTF16PtrFromString("")
if err != nil {
return err
}
wc := _WNDCLASS{
LpszClassName: swc,
LpfnWndProc: syscall.NewCallback(screenWindowWndProc),
HIcon: hDefaultIcon,
HCursor: hDefaultCursor,
HInstance: hThisInstance,
HbrBackground: syscall.Handle(_COLOR_BTNFACE + 1),
}
_, err = _RegisterClass(&wc)
if err != nil {
return err
}
screenHWND, err = _CreateWindowEx(0,
swc, emptyString,
_WS_OVERLAPPEDWINDOW,
_CW_USEDEFAULT, _CW_USEDEFAULT,
_CW_USEDEFAULT, _CW_USEDEFAULT,
_HWND_MESSAGE, 0, hThisInstance, 0)
if err != nil {
return err
}
return nil
}
func closeScreenWindow() (err error) {
// first destroy window
_DestroyWindow(screenHWND)
// then unregister class
swc, err := syscall.UTF16PtrFromString(screenWindowClass)
if err != nil {
return err
}
_UnregisterClass(swc, hThisInstance)
return nil
}
var (
hDefaultIcon syscall.Handle
hDefaultCursor syscall.Handle
hThisInstance syscall.Handle
)
func initCommon() (err error) {
hDefaultIcon, err = _LoadIcon(0, _IDI_APPLICATION)
if err != nil {
return err
}
hDefaultCursor, err = _LoadCursor(0, _IDC_ARROW)
if err != nil {
return err
}
// TODO(andlabs) hThisInstance
return nil
}
//go:uintptrescapes
func SendMessage(hwnd syscall.Handle, uMsg uint32, wParam uintptr, lParam uintptr) (lResult uintptr) {
return sendMessage(hwnd, uMsg, wParam, lParam)
}
var mainCallback func()
func Main(f func()) (retErr error) {
// It does not matter which OS thread we are on.
// All that matters is that we confine all UI operations
// to the thread that created the respective window.
runtime.LockOSThread()
if err := initCommon(); err != nil {
return err
}
if err := initScreenWindow(); err != nil {
return err
}
defer func() {
// TODO(andlabs): log an error if this fails?
closeScreenWindow()
}()
if err := initWindowClass(); err != nil {
return err
}
defer func() {
// TODO(andlabs): log an error if this fails?
closeWindowClass()
}()
// Prime the pump.
mainCallback = f
_PostMessage(screenHWND, msgMainCallback, 0, 0)
// Main message pump.
var m _MSG
for {
done, err := _GetMessage(&m, 0, 0, 0)
if err != nil {
return fmt.Errorf("win32 GetMessage failed: %v", err)
}
if done == 0 { // WM_QUIT
break
}
_TranslateMessage(&m)
_DispatchMessage(&m)
}
return nil
}