ebiten/internal/devicescale/impl_windows.go

257 lines
5.8 KiB
Go

// Copyright 2018 The Ebiten Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package devicescale
import (
"fmt"
"runtime"
"unsafe"
"golang.org/x/sys/windows"
)
const (
logPixelsX = 88
monitorDefaultToNearest = 2
mdtEffectiveDpi = 0
)
type rect struct {
left int32
top int32
right int32
bottom int32
}
var (
user32 = windows.NewLazySystemDLL("user32")
gdi32 = windows.NewLazySystemDLL("gdi32")
shcore = windows.NewLazySystemDLL("shcore")
)
var (
procSetProcessDPIAware = user32.NewProc("SetProcessDPIAware")
procGetWindowDC = user32.NewProc("GetWindowDC")
procReleaseDC = user32.NewProc("ReleaseDC")
procMonitorFromRect = user32.NewProc("MonitorFromRect")
procGetMonitorInfo = user32.NewProc("GetMonitorInfoW")
procGetDeviceCaps = gdi32.NewProc("GetDeviceCaps")
// GetScaleFactorForMonitor function can return unrelaiavle value (e.g. returning 180
// for 200% scale). Use GetDpiForMonitor instead.
procGetDpiForMonitor = shcore.NewProc("GetDpiForMonitor")
)
var shcoreAvailable = false
type winErr struct {
FuncName string
Code windows.Errno
Return uintptr
}
func (e *winErr) Error() string {
return fmt.Sprintf("devicescale: %s failed: error code: %d", e.FuncName, e.Code)
}
func init() {
if shcore.Load() == nil {
shcoreAvailable = true
}
}
func setProcessDPIAware() error {
r, _, e := procSetProcessDPIAware.Call()
if e != nil && e.(windows.Errno) != 0 {
return &winErr{
FuncName: "SetProcessDPIAware",
Code: e.(windows.Errno),
}
}
if r == 0 {
return &winErr{
FuncName: "SetProcessDPIAware",
Return: r,
}
}
return nil
}
func getWindowDC(hwnd uintptr) (uintptr, error) {
r, _, e := procGetWindowDC.Call(hwnd)
if e != nil && e.(windows.Errno) != 0 {
return 0, &winErr{
FuncName: "GetWindowDC",
Code: e.(windows.Errno),
}
}
if r == 0 {
return 0, &winErr{
FuncName: "GetWindowDC",
Return: r,
}
}
return r, nil
}
func releaseDC(hwnd, hdc uintptr) error {
r, _, e := procReleaseDC.Call(hwnd, hdc)
if e != nil && e.(windows.Errno) != 0 {
return &winErr{
FuncName: "ReleaseDC",
Code: e.(windows.Errno),
}
}
if r == 0 {
return &winErr{
FuncName: "ReleaseDC",
Return: r,
}
}
return nil
}
func getDeviceCaps(hdc uintptr, nindex int) (int, error) {
r, _, e := procGetDeviceCaps.Call(hdc, uintptr(nindex))
if e != nil && e.(windows.Errno) != 0 {
return 0, &winErr{
FuncName: "GetDeviceCaps",
Code: e.(windows.Errno),
}
}
return int(r), nil
}
func monitorFromRect(lprc *rect, dwFlags int) (uintptr, error) {
r, _, e := procMonitorFromRect.Call(uintptr(unsafe.Pointer(lprc)), uintptr(dwFlags))
runtime.KeepAlive(lprc)
if e != nil && e.(windows.Errno) != 0 {
return 0, &winErr{
FuncName: "MonitorFromRect",
Code: e.(windows.Errno),
}
}
if r == 0 {
return 0, &winErr{
FuncName: "MonitorFromRect",
Return: r,
}
}
return r, nil
}
func getMonitorInfo(hMonitor uintptr, lpMonitorInfo uintptr) error {
r, _, e := procGetMonitorInfo.Call(hMonitor, lpMonitorInfo)
if e != nil && e.(windows.Errno) != 0 {
return &winErr{
FuncName: "GetMonitorInfo",
Code: e.(windows.Errno),
}
}
if r == 0 {
return &winErr{
FuncName: "GetMonitorInfo",
Return: r,
}
}
return nil
}
func getDpiForMonitor(hMonitor uintptr, dpiType uintptr, dpiX, dpiY *uint32) error {
r, _, e := procGetDpiForMonitor.Call(hMonitor, dpiType, uintptr(unsafe.Pointer(dpiX)), uintptr(unsafe.Pointer(dpiY)))
if e != nil && e.(windows.Errno) != 0 {
return &winErr{
FuncName: "GetDpiForMonitor",
Code: e.(windows.Errno),
}
}
if r != 0 {
return &winErr{
FuncName: "GetDpiForMonitor",
Return: r,
}
}
return nil
}
func getFromLogPixelSx() float64 {
dc, err := getWindowDC(0)
if err != nil {
const (
errorInvalidWindowHandle = 1400
errorResourceDataNotFound = 1812
)
// On Wine, it looks like GetWindowDC(0) doesn't work (#738, #743).
code := err.(*winErr).Code
if code == errorInvalidWindowHandle {
return 1
}
if code == errorResourceDataNotFound {
return 1
}
panic(err)
}
// Note that GetDeviceCaps with LOGPIXELSX always returns a same value for any monitors
// even if multiple monitors are used.
dpi, err := getDeviceCaps(dc, logPixelsX)
if err != nil {
panic(err)
}
if err := releaseDC(0, dc); err != nil {
panic(err)
}
return float64(dpi) / 96
}
func impl(x, y int) float64 {
if err := setProcessDPIAware(); err != nil {
panic(err)
}
// On Windows 7 or older, shcore.dll is not available.
if !shcoreAvailable {
return getFromLogPixelSx()
}
lprc := rect{
left: int32(x),
right: int32(x + 1),
top: int32(y),
bottom: int32(y + 1),
}
// MonitorFromPoint requires to pass a POINT value, and there seems no portable way to
// do this with Cgo. Use MonitorFromRect instead.
m, err := monitorFromRect(&lprc, monitorDefaultToNearest)
if err != nil {
// monitorFromRect can fail in some environments (#1612)
return getFromLogPixelSx()
}
dpiX := uint32(0)
dpiY := uint32(0) // Passing dpiY is needed even though this is not used, or GetDpiForMonitor returns an error.
if err := getDpiForMonitor(m, mdtEffectiveDpi, &dpiX, &dpiY); err != nil {
// getDpiForMonitor can fail in some environments (#1612)
return getFromLogPixelSx()
}
runtime.KeepAlive(dpiY)
return float64(dpiX) / 96
}