From ed3a4a734ee334d52f684bfdde230465b00ab61c Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Mon, 24 Aug 2020 00:33:18 +0900
Subject: [PATCH] uidriver/glfw: Refactoring

---
 internal/uidriver/glfw/ui.go         | 14 ++++++--------
 internal/uidriver/glfw/ui_darwin.go  |  8 ++++----
 internal/uidriver/glfw/ui_unix.go    |  4 ++--
 internal/uidriver/glfw/ui_windows.go |  6 +++---
 4 files changed, 15 insertions(+), 17 deletions(-)

diff --git a/internal/uidriver/glfw/ui.go b/internal/uidriver/glfw/ui.go
index 2b10cec28..fe48a0733 100644
--- a/internal/uidriver/glfw/ui.go
+++ b/internal/uidriver/glfw/ui.go
@@ -145,12 +145,14 @@ func initialize() error {
 		panic("glfw: glfw.CreateWindow must not return nil")
 	}
 
-	// Create a window and leave it as it is: this affects the result of currentMonitorFromPosition.
+	// Create a window and set it: this affects toDeviceIndependentPixel and deviceScaleFactor.
 	theUI.window = w
-	theUI.initMonitor = theUI.currentMonitor()
+	theUI.initMonitor = currentMonitorByOS(w)
 	v := theUI.initMonitor.GetVideoMode()
 	theUI.initFullscreenWidthInDP = int(theUI.toDeviceIndependentPixel(float64(v.Width)))
 	theUI.initFullscreenHeightInDP = int(theUI.toDeviceIndependentPixel(float64(v.Height)))
+	theUI.window.Destroy()
+	theUI.window = nil
 
 	return nil
 }
@@ -671,10 +673,6 @@ func (u *UserInterface) createWindow() error {
 
 func (u *UserInterface) run() error {
 	if err := u.t.Call(func() error {
-		// The window is created at initialize().
-		u.window.Destroy()
-		u.window = nil
-
 		if u.Graphics().IsGL() {
 			glfw.WindowHint(glfw.ClientAPI, glfw.OpenGLAPI)
 			glfw.WindowHint(glfw.ContextVersionMajor, 2)
@@ -1100,9 +1098,9 @@ func (u *UserInterface) currentMonitor() *glfw.Monitor {
 	}
 
 	// Getting a monitor from a window position is not reliable in general (e.g., when a window is put across
-	// multiple monitors).
+	// multiple monitors. A window position is not reliable before SetWindowPosition is called.).
 	// Get the monitor which the current window belongs to. This requires OS API.
-	return u.currentMonitorFromPosition()
+	return currentMonitorByOS(u.window)
 }
 
 func (u *UserInterface) SetScreenTransparent(transparent bool) {
diff --git a/internal/uidriver/glfw/ui_darwin.go b/internal/uidriver/glfw/ui_darwin.go
index eb1f3ae43..3ce0925d9 100644
--- a/internal/uidriver/glfw/ui_darwin.go
+++ b/internal/uidriver/glfw/ui_darwin.go
@@ -55,11 +55,11 @@ func (u *UserInterface) adjustWindowPosition(x, y int) (int, int) {
 	return x, y
 }
 
-func (u *UserInterface) currentMonitorFromPosition() *glfw.Monitor {
+func currentMonitorByOS(w *glfw.Window) *glfw.Monitor {
 	x := C.int(0)
 	y := C.int(0)
-	// Note: [NSApp mainWindow] is nil when it doesn't have its border. Use u.window here.
-	win := u.window.GetCocoaWindow()
+	// Note: [NSApp mainWindow] is nil when it doesn't have its border. Use w here.
+	win := w.GetCocoaWindow()
 	C.currentMonitorPos(win, &x, &y)
 	for _, m := range glfw.GetMonitors() {
 		mx, my := m.GetPos()
@@ -68,7 +68,7 @@ func (u *UserInterface) currentMonitorFromPosition() *glfw.Monitor {
 		}
 	}
 
-	if m, ok := getCachedMonitor(u.window.GetPos()); ok {
+	if m, ok := getCachedMonitor(w.GetPos()); ok {
 		return m.m
 	}
 	return glfw.GetPrimaryMonitor()
diff --git a/internal/uidriver/glfw/ui_unix.go b/internal/uidriver/glfw/ui_unix.go
index f6b84b51f..b3d1f6771 100644
--- a/internal/uidriver/glfw/ui_unix.go
+++ b/internal/uidriver/glfw/ui_unix.go
@@ -32,9 +32,9 @@ func (u *UserInterface) adjustWindowPosition(x, y int) (int, int) {
 	return x, y
 }
 
-func (u *UserInterface) currentMonitorFromPosition() *glfw.Monitor {
+func currentMonitorByOS(w *glfw.Window) *glfw.Monitor {
 	// TODO: Implement this correctly. (#1119).
-	if cm, ok := getCachedMonitor(u.window.GetPos()); ok {
+	if cm, ok := getCachedMonitor(w.GetPos()); ok {
 		return cm.m
 	}
 	return glfw.GetPrimaryMonitor()
diff --git a/internal/uidriver/glfw/ui_windows.go b/internal/uidriver/glfw/ui_windows.go
index cf05e70fb..613128e07 100644
--- a/internal/uidriver/glfw/ui_windows.go
+++ b/internal/uidriver/glfw/ui_windows.go
@@ -120,15 +120,15 @@ func (u *UserInterface) adjustWindowPosition(x, y int) (int, int) {
 	return x, y
 }
 
-func (u *UserInterface) currentMonitorFromPosition() *glfw.Monitor {
+func currentMonitorByOS(glfww *glfw.Window) *glfw.Monitor {
 	fallback := func() *glfw.Monitor {
-		if m, ok := getCachedMonitor(u.window.GetPos()); ok {
+		if m, ok := getCachedMonitor(glfww.GetPos()); ok {
 			return m.m
 		}
 		return glfw.GetPrimaryMonitor()
 	}
 
-	// TODO: Should we use u.window.GetWin32Window() here?
+	// TODO: Should we use glfww.GetWin32Window() here?
 	w, err := getActiveWindow()
 	if err != nil {
 		panic(err)