Add internal/devicescale

internal/devicescale/devicescale.go

@@ -0,0 +1,25 @@
+// 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
+
+var scale = 0.0
+
+func DeviceScale() float64 {
+	if scale != 0.0 {
+		return scale
+	}
+	scale = impl()
+	return scale
+}

internal/devicescale/devicescale_android.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package ui
+package devicescale
 
 /*
 
@@ -63,19 +63,13 @@ import (
 	"github.com/hajimehoshi/ebiten/internal/jni"
 )
 
-var (
-	androidDeviceScale = 0.0
-)
-
-func deviceScale() float64 {
-	if 0 < androidDeviceScale {
-		return androidDeviceScale
-	}
+func impl() float64 {
+	s := 0.0
 	if err := jni.RunOnJVM(func(vm, env, ctx uintptr) error {
-		androidDeviceScale = float64(C.deviceScale(C.uintptr_t(vm), C.uintptr_t(env), C.uintptr_t(ctx)))
+		s = float64(C.deviceScale(C.uintptr_t(vm), C.uintptr_t(env), C.uintptr_t(ctx)))
 		return nil
 	}); err != nil {
-		panic(fmt.Sprintf("ui: error %v", err))
+		panic(fmt.Sprintf("devicescale: error %v", err))
 	}
-	return androidDeviceScale
+	return s
 }

internal/devicescale/devicescale_ios.go

@@ -14,7 +14,7 @@
 
 // +build ios
 
-package ui
+package devicescale
 
 // #cgo CFLAGS: -x objective-c
 // #cgo LDFLAGS: -framework Foundation -framework UIKit
@@ -26,6 +26,6 @@ package ui
 // }
 import "C"
 
-func deviceScale() float64 {
+func impl() float64 {
 	return float64(C.devicePixelRatio())
 }

internal/devicescale/devicescale_js.go

@@ -0,0 +1,29 @@
+// 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.
+
+// +build js
+
+package devicescale
+
+import (
+	"github.com/gopherjs/gopherjs/js"
+)
+
+func impl() float64 {
+	ratio := js.Global.Get("window").Get("devicePixelRatio").Float()
+	if ratio == 0 {
+		ratio = 1
+	}
+	return ratio
+}

internal/devicescale/devicescale_mac.go

@@ -0,0 +1,34 @@
+// 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.
+
+// +build darwin
+// +build !js
+// +build !ios
+
+package devicescale
+
+// #cgo CFLAGS: -x objective-c
+// #cgo LDFLAGS: -framework AppKit
+//
+// #import <AppKit/AppKit.h>
+//
+// static float scale() {
+//   NSScreen* primary = [[NSScreen screens] firstObject];
+//   return [primary backingScaleFactor];
+// }
+import "C"
+
+func impl() float64 {
+	return float64(C.scale())
+}

internal/devicescale/devicescale_windows.go

@@ -0,0 +1,41 @@
+// 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.
+
+// +build !js
+
+package devicescale
+
+// TODO: Use golang.org/x/sys/windows (NewLazyDLL) instead of cgo.
+
+// #cgo LDFLAGS: -lgdi32
+//
+// #include <windows.h>
+//
+// static char* getDPI(int* dpi) {
+//   HDC dc = GetWindowDC(0);
+//   *dpi = GetDeviceCaps(dc, LOGPIXELSX);
+//   if (!ReleaseDC(0, dc)) {
+//     return "ReleaseDC failed";
+//   }
+//   return "";
+// }
+import "C"
+
+func impl() float64 {
+	dpi := C.int(0)
+	if errmsg := C.GoString(C.getDPI(&dpi)); errmsg != "" {
+		panic(errmsg)
+	}
+	return float64(dpi) / 96
+}

internal/devicescale/devicescale_xwindow.go

@@ -0,0 +1,24 @@
+// 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.
+
+// +build freebsd linux
+// +build !js
+// +build !android
+
+package devicescale
+
+func impl() float64 {
+	// TODO: Implement this
+	return 1
+}

internal/ui/ui_glfw.go

@@ -27,6 +27,8 @@ import (
 	"time"
 
 	"github.com/go-gl/glfw/v3.2/glfw"
+
+	"github.com/hajimehoshi/ebiten/internal/devicescale"
 	"github.com/hajimehoshi/ebiten/internal/opengl"
 )
 
@@ -38,7 +40,6 @@ type userInterface struct {
 	height      int
 
 	scale           float64
-	cachedDeviceScale float64
 	cachedGLFWScale float64
 	fullscreenScale float64
 
@@ -309,9 +310,10 @@ func ScreenOffset() (float64, float64) {
 	oy := 0.0
 	m := glfw.GetPrimaryMonitor()
 	v := m.GetVideoMode()
+	d := devicescale.DeviceScale()
 	_ = u.runOnMainThread(func() error {
-		ox = (float64(v.Width)*u.deviceScale()/u.glfwScale() - float64(u.width)*u.actualScreenScale()) / 2
-		oy = (float64(v.Height)*u.deviceScale()/u.glfwScale() - float64(u.height)*u.actualScreenScale()) / 2
+		ox = (float64(v.Width)*d/u.glfwScale() - float64(u.width)*u.actualScreenScale()) / 2
+		oy = (float64(v.Height)*d/u.glfwScale() - float64(u.height)*u.actualScreenScale()) / 2
 		return nil
 	})
 	return ox, oy
@@ -395,13 +397,6 @@ func (u *userInterface) glfwScale() float64 {
 	return u.cachedGLFWScale
 }
 
-func (u *userInterface) deviceScale() float64 {
-	if u.cachedDeviceScale == 0 {
-		u.cachedDeviceScale = deviceScale()
-	}
-	return u.cachedDeviceScale
-}
-
 func (u *userInterface) glfwSize() (int, int) {
 	w := int(float64(u.windowWidth) * u.getScale() * u.glfwScale())
 	h := int(float64(u.height) * u.getScale() * u.glfwScale())
@@ -427,7 +422,7 @@ func (u *userInterface) getScale() float64 {
 }
 
 func (u *userInterface) actualScreenScale() float64 {
-	return u.getScale() * u.deviceScale()
+	return u.getScale() * devicescale.DeviceScale()
 }
 
 func (u *userInterface) pollEvents() {
@@ -525,7 +520,7 @@ func (u *userInterface) setScreenSize(width, height int, scale float64, fullscre
 
 	u.width = width
 	u.windowWidth = width
-	s := scale * u.deviceScale()
+	s := scale * devicescale.DeviceScale()
 	if int(float64(width)*s) < minWindowWidth {
 		u.windowWidth = int(math.Ceil(minWindowWidth / s))
 	}

internal/ui/ui_js.go

@@ -22,6 +22,8 @@ import (
 	"unicode"
 
 	"github.com/gopherjs/gopherjs/js"
+
+	"github.com/hajimehoshi/ebiten/internal/devicescale"
 	"github.com/hajimehoshi/ebiten/internal/opengl"
 )
 
@@ -346,14 +348,6 @@ func setMouseCursorFromEvent(e *js.Object) {
 	currentInput.setMouseCursor(int(float64(x)/scale), int(float64(y)/scale))
 }
 
-func devicePixelRatio() float64 {
-	ratio := js.Global.Get("window").Get("devicePixelRatio").Float()
-	if ratio == 0 {
-		ratio = 1
-	}
-	return ratio
-}
-
 func RunMainThreadLoop(ch <-chan error) error {
 	return <-ch
 }
@@ -389,7 +383,7 @@ func (u *userInterface) updateScreenSize() {
 	// * Chrome just after restoring the lost context
 	// * Safari
 	// Let's use the pixel ratio as it is here.
-	u.deviceScale = devicePixelRatio()
+	u.deviceScale = devicescale.DeviceScale()
 
 	canvas.Set("width", int(float64(u.width)*u.actualScreenScale()))
 	canvas.Set("height", int(float64(u.height)*u.actualScreenScale()))

internal/ui/ui_mac.go

@@ -18,21 +18,6 @@
 
 package ui
 
-// #cgo CFLAGS: -x objective-c
-// #cgo LDFLAGS: -framework AppKit
-//
-// #import <AppKit/AppKit.h>
-//
-// static float scale() {
-//   NSScreen* primary = [[NSScreen screens] firstObject];
-//   return [primary backingScaleFactor];
-// }
-import "C"
-
-func deviceScale() float64 {
-	return float64(C.scale())
-}
-
 func glfwScale() float64 {
 	return 1
 }

internal/ui/ui_mobile.go

@@ -23,6 +23,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/hajimehoshi/ebiten/internal/devicescale"
 	"github.com/hajimehoshi/ebiten/internal/opengl"
 )
 
@@ -96,7 +97,7 @@ func (u *userInterface) update(g GraphicsContext) error {
 	if sizeChanged {
 		width = u.width
 		height = u.height
-		actualScale = u.scale * deviceScale()
+		actualScale = u.scale * devicescale.DeviceScale()
 	}
 	u.sizeChanged = false
 	u.m.Unlock()

internal/ui/ui_windows.go

@@ -22,30 +22,17 @@ package ui
 //
 // #include <windows.h>
 //
-// static char* getDPI(int* dpi) {
-//   HDC dc = GetWindowDC(0);
-//   *dpi = GetDeviceCaps(dc, LOGPIXELSX);
-//   if (!ReleaseDC(0, dc)) {
-//     return "ReleaseDC failed";
-//   }
-//   return "";
-// }
-//
 // static int getCaptionHeight() {
 //   return GetSystemMetrics(SM_CYCAPTION);
 // }
 import "C"
 
-func deviceScale() float64 {
-	dpi := C.int(0)
-	if errmsg := C.GoString(C.getDPI(&dpi)); errmsg != "" {
-		panic(errmsg)
-	}
-	return float64(dpi) / 96
-}
+import (
+	"github.com/hajimehoshi/ebiten/internal/devicescale"
+)
 
 func glfwScale() float64 {
-	return deviceScale()
+	return devicescale.DeviceScale()
 }
 
 func adjustWindowPosition(x, y int) (int, int) {

internal/ui/ui_xwindow.go

@@ -18,13 +18,12 @@
 
 package ui
 
-func deviceScale() float64 {
-	// TODO: Implement this
-	return 1
-}
+import (
+	"github.com/hajimehoshi/ebiten/internal/devicescale"
+)
 
 func glfwScale() float64 {
-	return deviceScale()
+	return devicescale.DeviceScale()
 }
 
 func adjustWindowPosition(x, y int) (int, int) {