Move VideoModeScaleAt into internal/uidriver/glfw. (#1812)

It's only used by GLFW, and has been in devicescale only to ease migration
to separate video mode vs content scaling.

Updates #1774

internal/devicescale/devicescale.go

@@ -23,9 +23,8 @@ type pos struct {
 }
 
 var (
-	m                   sync.Mutex
-	cache               = map[pos]float64{}
-	videoModeScaleCache = map[pos]float64{}
+	m     sync.Mutex
+	cache = map[pos]float64{}
 )
 
 // GetAt returns the device scale at (x, y), i.e. the number of device-dependent pixels per device-independent pixel.
@@ -46,16 +45,3 @@ func GetAt(x, y int) float64 {
 
 	return s
 }
-
-// VideoModeScaleAt returns the video mode scale scale at (x, y), i.e. the number of video mode pixels per device-dependent pixel.
-// x and y are in device-dependent pixels and must be the top-left coordinate of a monitor, or 0,0 to request a "global scale".
-func VideoModeScaleAt(x, y int) float64 {
-	m.Lock()
-	defer m.Unlock()
-	if s, ok := videoModeScaleCache[pos{x, y}]; ok {
-		return s
-	}
-	s := videoModeScaleImpl(x, y)
-	videoModeScaleCache[pos{x, y}] = s
-	return s
-}

internal/devicescale/impl_android.go

@@ -103,7 +103,3 @@ func impl(x, y int) float64 {
 	}
 	return s
 }
-
-func videoModeScaleImpl(x, y int) float64 {
-	return 1
-}

internal/devicescale/impl_ios.go

@@ -30,7 +30,3 @@ import "C"
 func impl(x, y int) float64 {
 	return float64(C.devicePixelRatio())
 }
-
-func videoModeScaleImpl(x, y int) float64 {
-	return 1
-}

internal/devicescale/impl_js.go

@@ -33,7 +33,3 @@ func impl(x, y int) float64 {
 	}
 	return ratio
 }
-
-func videoModeScaleImpl(x, y int) float64 {
-	return 1
-}

internal/devicescale/impl_notx.go

@@ -1,22 +0,0 @@
-// Copyright 2021 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.
-
-//go:build (darwin && !ios) || windows
-// +build darwin,!ios windows
-
-package devicescale
-
-func videoModeScaleImpl(x, y int) float64 {
-	return 1
-}

internal/devicescale/impl_x.go

@@ -1,82 +0,0 @@
-// Copyright 2021 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.
-
-//go:build !android && !darwin && !js && !windows
-// +build !android,!darwin,!js,!windows
-
-package devicescale
-
-import (
-	"math"
-
-	"github.com/jezek/xgb"
-	"github.com/jezek/xgb/randr"
-	"github.com/jezek/xgb/xproto"
-)
-
-func videoModeScaleImpl(x, y int) float64 {
-	// TODO: if https://github.com/glfw/glfw/issues/1961 gets fixed, this function may need revising.
-	// In case GLFW decides to switch to returning logical pixels, we can just return 1.
-
-	// Note: GLFW currently returns physical pixel sizes,
-	// but we need to predict the window system-side size of the fullscreen window
-	// for our `ScreenSizeInFullscreen` public API.
-	// Also at the moment we need this prior to switching to fullscreen, but that might be replacable.
-	// So this function computes the ratio of physical per logical pixels.
-	m := monitorAt(x, y)
-	monitorX, monitorY := m.GetPos()
-	xconn, err := xgb.NewConn()
-	defer xconn.Close()
-	if err != nil {
-		// No X11 connection?
-		// Assume we're on pure Wayland then.
-		// GLFW/Wayland shouldn't be having this issue.
-		return 1
-	}
-	if err = randr.Init(xconn); err != nil {
-		// No RANDR extension?
-		// No problem.
-		return 1
-	}
-	root := xproto.Setup(xconn).DefaultScreen(xconn).Root
-	res, err := randr.GetScreenResourcesCurrent(xconn, root).Reply()
-	if err != nil {
-		// Likely means RANDR is not working.
-		// No problem.
-		return 1
-	}
-	for _, crtc := range res.Crtcs[:res.NumCrtcs] {
-		info, err := randr.GetCrtcInfo(xconn, crtc, res.ConfigTimestamp).Reply()
-		if err != nil {
-			// This Crtc is bad. Maybe just got disconnected?
-			continue
-		}
-		if info.NumOutputs == 0 {
-			// This Crtc is not connected to any output.
-			// In other words, a disabled monitor.
-			continue
-		}
-		if int(info.X) == monitorX && int(info.Y) == monitorY {
-			xWidth, xHeight := info.Width, info.Height
-			vm := m.GetVideoMode()
-			physWidth, physHeight := vm.Width, vm.Height
-			// Return one scale, even though there may be separate X and Y scales.
-			// Return the _larger_ scale, as this would yield a letterboxed display on mismatch, rather than a cut-off one.
-			scale := math.Max(float64(physWidth)/float64(xWidth), float64(physHeight)/float64(xHeight))
-			return scale
-		}
-	}
-	// Monitor not known to XRandR. Weird.
-	return 1
-}

internal/uidriver/glfw/ui.go

@@ -189,8 +189,7 @@ func initialize() error {
 	m := currentMonitor(w)
 	theUI.initMonitor = m
 	v := m.GetVideoMode()
-	mx, my := currentMonitor(w).GetPos()
-	scale := devicescale.VideoModeScaleAt(mx, my)
+	scale := videoModeScale(currentMonitor(w))
 	theUI.initFullscreenWidthInDP = int(theUI.fromGLFWMonitorPixel(float64(v.Width), scale))
 	theUI.initFullscreenHeightInDP = int(theUI.fromGLFWMonitorPixel(float64(v.Height), scale))
 
@@ -232,6 +231,7 @@ func updateMonitors() {
 			y:  y,
 		})
 	}
+	clearVideoModeScaleCache()
 }
 
 func ensureMonitors() []*monitor {
@@ -531,8 +531,7 @@ func (u *UserInterface) ScreenSizeInFullscreen() (int, int) {
 	_ = u.t.Call(func() error {
 		m := currentMonitor(u.window)
 		v := m.GetVideoMode()
-		mx, my := m.GetPos()
-		s := devicescale.VideoModeScaleAt(mx, my)
+		s := videoModeScale(m)
 		w = int(u.fromGLFWMonitorPixel(float64(v.Width), s))
 		h = int(u.fromGLFWMonitorPixel(float64(v.Height), s))
 		return nil
@@ -940,8 +939,7 @@ func (u *UserInterface) updateSize() (float64, float64, bool) {
 		m := currentMonitor(u.window)
 		v := m.GetVideoMode()
 		ww, wh := v.Width, v.Height
-		mx, my := m.GetPos()
-		s := devicescale.VideoModeScaleAt(mx, my)
+		s := videoModeScale(m)
 		w = u.fromGLFWMonitorPixel(float64(ww), s)
 		h = u.fromGLFWMonitorPixel(float64(wh), s)
 	} else {

internal/uidriver/glfw/ui_darwin.go

@@ -81,6 +81,14 @@ import (
 	"github.com/hajimehoshi/ebiten/v2/internal/glfw"
 )
 
+// clearVideoModeScaleCache must be called from the main thread.
+func clearVideoModeScaleCache() {}
+
+// videoModeScale must be called from the main thread.
+func videoModeScale(m *glfw.Monitor) float64 {
+	return 1
+}
+
 // fromGLFWMonitorPixel must be called from the main thread.
 func (u *UserInterface) fromGLFWMonitorPixel(x float64, videoModeScale float64) float64 {
 	// videoModeScale is always 1 on macOS,

internal/uidriver/glfw/ui_unix.go

@@ -19,10 +19,96 @@
 package glfw
 
 import (
+	"math"
+
 	"github.com/hajimehoshi/ebiten/v2/internal/driver"
 	"github.com/hajimehoshi/ebiten/v2/internal/glfw"
+	"github.com/jezek/xgb"
+	"github.com/jezek/xgb/randr"
+	"github.com/jezek/xgb/xproto"
 )
 
+type videoModeScaleCacheKey struct{ X, Y int }
+
+var videoModeScaleCache = map[videoModeScaleCacheKey]float64{}
+
+// clearVideoModeScaleCache must be called from the main thread.
+func clearVideoModeScaleCache() {
+	for k := range videoModeScaleCache {
+		delete(videoModeScaleCache, k)
+	}
+}
+
+// videoModeScale must be called from the main thread.
+func videoModeScale(m *glfw.Monitor) float64 {
+	// Caching wrapper for videoModeScaleUncached as
+	// videoModeScaleUncached may be expensive (uses blocking calls on X connection)
+	// and public ScreenSizeInFullscreen API needs the videoModeScale.
+	monitorX, monitorY := m.GetPos()
+	cacheKey := videoModeScaleCacheKey{X: monitorX, Y: monitorY}
+	if cached, ok := videoModeScaleCache[cacheKey]; ok {
+		return cached
+	}
+	scale := videoModeScaleUncached(m, monitorX, monitorY)
+	videoModeScaleCache[cacheKey] = scale
+	return scale
+}
+
+// videoModeScaleUncached must be called from the main thread.
+func videoModeScaleUncached(m *glfw.Monitor, monitorX, monitorY int) float64 {
+	// TODO: if https://github.com/glfw/glfw/issues/1961 gets fixed, this function may need revising.
+	// In case GLFW decides to switch to returning logical pixels, we can just return 1.
+
+	// Note: GLFW currently returns physical pixel sizes,
+	// but we need to predict the window system-side size of the fullscreen window
+	// for our `ScreenSizeInFullscreen` public API.
+	// Also at the moment we need this prior to switching to fullscreen, but that might be replacable.
+	// So this function computes the ratio of physical per logical pixels.
+	xconn, err := xgb.NewConn()
+	defer xconn.Close()
+	if err != nil {
+		// No X11 connection?
+		// Assume we're on pure Wayland then.
+		// GLFW/Wayland shouldn't be having this issue.
+		return 1
+	}
+	if err = randr.Init(xconn); err != nil {
+		// No RANDR extension?
+		// No problem.
+		return 1
+	}
+	root := xproto.Setup(xconn).DefaultScreen(xconn).Root
+	res, err := randr.GetScreenResourcesCurrent(xconn, root).Reply()
+	if err != nil {
+		// Likely means RANDR is not working.
+		// No problem.
+		return 1
+	}
+	for _, crtc := range res.Crtcs[:res.NumCrtcs] {
+		info, err := randr.GetCrtcInfo(xconn, crtc, res.ConfigTimestamp).Reply()
+		if err != nil {
+			// This Crtc is bad. Maybe just got disconnected?
+			continue
+		}
+		if info.NumOutputs == 0 {
+			// This Crtc is not connected to any output.
+			// In other words, a disabled monitor.
+			continue
+		}
+		if int(info.X) == monitorX && int(info.Y) == monitorY {
+			xWidth, xHeight := info.Width, info.Height
+			vm := m.GetVideoMode()
+			physWidth, physHeight := vm.Width, vm.Height
+			// Return one scale, even though there may be separate X and Y scales.
+			// Return the _larger_ scale, as this would yield a letterboxed display on mismatch, rather than a cut-off one.
+			scale := math.Max(float64(physWidth)/float64(xWidth), float64(physHeight)/float64(xHeight))
+			return scale
+		}
+	}
+	// Monitor not known to XRandR. Weird.
+	return 1
+}
+
 // fromGLFWMonitorPixel must be called from the main thread.
 func (u *UserInterface) fromGLFWMonitorPixel(x float64, videoModeScale float64) float64 {
 	return x / (videoModeScale * u.deviceScaleFactor())

internal/uidriver/glfw/ui_windows.go

@@ -98,6 +98,14 @@ func getMonitorInfoW(hMonitor uintptr, lpmi *monitorInfo) error {
 	return nil
 }
 
+// clearVideoModeScaleCache must be called from the main thread.
+func clearVideoModeScaleCache() {}
+
+// videoModeScale must be called from the main thread.
+func videoModeScale(m *glfw.Monitor) float64 {
+	return 1
+}
+
 // fromGLFWMonitorPixel must be called from the main thread.
 func (u *UserInterface) fromGLFWMonitorPixel(x float64, videoModeScale float64) float64 {
 	return x / (videoModeScale * u.deviceScaleFactor())