From 5278a7c6d63ae43d8ad7949f4440bf19e2b18bf7 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sat, 19 Sep 2020 00:21:08 +0900
Subject: [PATCH] uidriver/glfw: Bug fix: Use the correct scale for GLFW APIs
 on Linux/UNIX

Updates #1307
---
 internal/uidriver/glfw/ui.go         | 16 +++-------------
 internal/uidriver/glfw/ui_darwin.go  |  8 ++++++--
 internal/uidriver/glfw/ui_unix.go    | 10 ++++++++--
 internal/uidriver/glfw/ui_windows.go | 10 ++++++++--
 internal/uidriver/glfw/window.go     |  8 ++++----
 5 files changed, 29 insertions(+), 23 deletions(-)

diff --git a/internal/uidriver/glfw/ui.go b/internal/uidriver/glfw/ui.go
index 76163f52c..29900ec43 100644
--- a/internal/uidriver/glfw/ui.go
+++ b/internal/uidriver/glfw/ui.go
@@ -390,16 +390,6 @@ func (u *UserInterface) setInitFocused(focused bool) {
 	u.m.Unlock()
 }
 
-// toDeviceIndependentPixel must be called from the main thread.
-func (u *UserInterface) toDeviceIndependentPixel(x float64) float64 {
-	return x / u.glfwScale()
-}
-
-// toDeviceDependentPixel must be called from the main thread.
-func (u *UserInterface) toDeviceDependentPixel(x float64) float64 {
-	return x * u.glfwScale()
-}
-
 func (u *UserInterface) ScreenSizeInFullscreen() (int, int) {
 	if !u.isRunning() {
 		return u.initFullscreenWidthInDP, u.initFullscreenHeightInDP
@@ -736,8 +726,8 @@ func (u *UserInterface) run() error {
 	}
 	setSize := func() {
 		ww, wh := u.getInitWindowSize()
-		ww = int(u.toDeviceDependentPixel(float64(ww)))
-		wh = int(u.toDeviceDependentPixel(float64(wh)))
+		ww = int(u.toGLFWPixel(float64(ww)))
+		wh = int(u.toGLFWPixel(float64(wh)))
 		u.setWindowSize(ww, wh, u.isFullscreen())
 	}
 
@@ -1000,7 +990,7 @@ func (u *UserInterface) setWindowSize(width, height int, fullscreen bool) {
 			// On Windows, giving a too small width doesn't call a callback (#165).
 			// To prevent hanging up, return asap if the width is too small.
 			// 126 is an arbitrary number and I guess this is small enough.
-			minWindowWidth := int(u.toDeviceDependentPixel(126))
+			minWindowWidth := int(u.toGLFWPixel(126))
 			if u.window.GetAttrib(glfw.Decorated) == glfw.False {
 				minWindowWidth = 1
 			}
diff --git a/internal/uidriver/glfw/ui_darwin.go b/internal/uidriver/glfw/ui_darwin.go
index 61a4e8ced..7839b649e 100644
--- a/internal/uidriver/glfw/ui_darwin.go
+++ b/internal/uidriver/glfw/ui_darwin.go
@@ -45,8 +45,12 @@ import (
 	"github.com/hajimehoshi/ebiten/internal/glfw"
 )
 
-func (u *UserInterface) glfwScale() float64 {
-	return 1
+func (u *UserInterface) toDeviceIndependentPixel(x float64) float64 {
+	return x
+}
+
+func (u *UserInterface) toGLFWPixel(x float64) float64 {
+	return x
 }
 
 func (u *UserInterface) adjustWindowPosition(x, y int) (int, int) {
diff --git a/internal/uidriver/glfw/ui_unix.go b/internal/uidriver/glfw/ui_unix.go
index 7b825841e..da130a227 100644
--- a/internal/uidriver/glfw/ui_unix.go
+++ b/internal/uidriver/glfw/ui_unix.go
@@ -22,8 +22,14 @@ import (
 	"github.com/hajimehoshi/ebiten/internal/glfw"
 )
 
-func (u *UserInterface) glfwScale() float64 {
-	return u.deviceScaleFactor()
+// toDeviceIndependentPixel must be called from the main thread.
+func (u *UserInterface) toDeviceIndependentPixel(x float64) float64 {
+	return x / u.deviceScaleFactor()
+}
+
+// toGLFWPixel must be called from the main thread.
+func (u *UserInterface) toGLFWPixel(x float64) float64 {
+	return x
 }
 
 func (u *UserInterface) adjustWindowPosition(x, y int) (int, int) {
diff --git a/internal/uidriver/glfw/ui_windows.go b/internal/uidriver/glfw/ui_windows.go
index 679ae56e8..d427ffa3e 100644
--- a/internal/uidriver/glfw/ui_windows.go
+++ b/internal/uidriver/glfw/ui_windows.go
@@ -99,8 +99,14 @@ func getMonitorInfoW(hMonitor uintptr, lpmi *monitorInfo) error {
 	return nil
 }
 
-func (u *UserInterface) glfwScale() float64 {
-	return u.deviceScaleFactor()
+// toDeviceIndependentPixel must be called from the main thread.
+func (u *UserInterface) toDeviceIndependentPixel(x float64) float64 {
+	return x / u.deviceScaleFactor()
+}
+
+// toGLFWPixel must be called from the main thread.
+func (u *UserInterface) toGLFWPixel(x float64) float64 {
+	return x * u.deviceScaleFactor()
 }
 
 func (u *UserInterface) adjustWindowPosition(x, y int) (int, int) {
diff --git a/internal/uidriver/glfw/window.go b/internal/uidriver/glfw/window.go
index 2451503a2..70f475a9a 100644
--- a/internal/uidriver/glfw/window.go
+++ b/internal/uidriver/glfw/window.go
@@ -210,8 +210,8 @@ func (w *window) SetPosition(x, y int) {
 			w.setPositionCalled = true
 		}()
 		mx, my := currentMonitor(w.ui.window).GetPos()
-		xf := w.ui.toDeviceDependentPixel(float64(x))
-		yf := w.ui.toDeviceDependentPixel(float64(y))
+		xf := w.ui.toGLFWPixel(float64(x))
+		yf := w.ui.toGLFWPixel(float64(y))
 		x, y := w.ui.adjustWindowPosition(mx+int(xf), my+int(yf))
 		if w.ui.isFullscreen() {
 			w.ui.origPosX, w.ui.origPosY = x, y
@@ -236,8 +236,8 @@ func (w *window) SetSize(width, height int) {
 		w.ui.setInitWindowSize(width, height)
 		return
 	}
-	ww := int(w.ui.toDeviceDependentPixel(float64(width)))
-	wh := int(w.ui.toDeviceDependentPixel(float64(height)))
+	ww := int(w.ui.toGLFWPixel(float64(width)))
+	wh := int(w.ui.toGLFWPixel(float64(height)))
 	w.ui.setWindowSize(ww, wh, w.ui.isFullscreen())
 }