From 18659ef4abc60bedf018dd1b8ea7e7e236166078 Mon Sep 17 00:00:00 2001
From: Tom Lister <tomlister3@gmail.com>
Date: Wed, 9 Feb 2022 21:11:25 +1100
Subject: [PATCH] internal/ui: add SetWindowKeepAspectRatio (#1985)

Updates #1804
---
 internal/glfw/glfw_notwindows.go |  8 +++++++
 internal/glfw/glfw_windows.go    |  9 +++++++
 internal/ui/ui_glfw.go           | 41 ++++++++++++++++++++++----------
 internal/ui/window_glfw.go       | 10 ++++++++
 internal/ui/window_null.go       |  3 +++
 window.go                        |  7 ++++++
 6 files changed, 66 insertions(+), 12 deletions(-)

diff --git a/internal/glfw/glfw_notwindows.go b/internal/glfw/glfw_notwindows.go
index 76c225830..58d85aa4e 100644
--- a/internal/glfw/glfw_notwindows.go
+++ b/internal/glfw/glfw_notwindows.go
@@ -208,6 +208,14 @@ func (w *Window) SetSizeLimits(minw, minh, maxw, maxh int) {
 	w.w.SetSizeLimits(minw, minh, maxw, maxh)
 }
 
+func (w *Window) SetKeepAspectRatio(keep bool) {
+	n, d := glfw.DontCare, glfw.DontCare
+	if keep {
+		n, d = w.GetSize()
+	}
+	w.w.SetAspectRatio(n, d)
+}
+
 func (w *Window) SetIcon(images []image.Image) {
 	w.w.SetIcon(images)
 }
diff --git a/internal/glfw/glfw_windows.go b/internal/glfw/glfw_windows.go
index a9154faac..afcc8f853 100644
--- a/internal/glfw/glfw_windows.go
+++ b/internal/glfw/glfw_windows.go
@@ -261,6 +261,15 @@ func (w *Window) SetSizeLimits(minw, minh, maxw, maxh int) {
 	panicError()
 }
 
+func (w *Window) SetKeepAspectRatio(keep bool) {
+	n, d := -1, -1
+	if keep {
+		n, d = w.GetSize()
+	}
+	glfwDLL.call("glfwSetWindowAspectRatio", w.w, uintptr(n), uintptr(d))
+	panicError()
+}
+
 func (w *Window) SetIcon(images []image.Image) {
 	gimgs := make([]glfwImage, len(images))
 	defer runtime.KeepAlive(gimgs)
diff --git a/internal/ui/ui_glfw.go b/internal/ui/ui_glfw.go
index 742e2a3fa..a6dd7db89 100644
--- a/internal/ui/ui_glfw.go
+++ b/internal/ui/ui_glfw.go
@@ -85,18 +85,19 @@ type UserInterface struct {
 	initFullscreenWidthInDIP  int
 	initFullscreenHeightInDIP int
 
-	initFullscreen           bool
-	initCursorMode           CursorMode
-	initWindowDecorated      bool
-	initWindowResizable      bool
-	initWindowPositionXInDIP int
-	initWindowPositionYInDIP int
-	initWindowWidthInDIP     int
-	initWindowHeightInDIP    int
-	initWindowFloating       bool
-	initWindowMaximized      bool
-	initScreenTransparent    bool
-	initFocused              bool
+	initFullscreen            bool
+	initCursorMode            CursorMode
+	initWindowDecorated       bool
+	initWindowResizable       bool
+	initWindowPositionXInDIP  int
+	initWindowPositionYInDIP  int
+	initWindowWidthInDIP      int
+	initWindowHeightInDIP     int
+	initWindowFloating        bool
+	initWindowMaximized       bool
+	initWindowKeepAspectRatio bool
+	initScreenTransparent     bool
+	initFocused               bool
 
 	fpsModeInited bool
 
@@ -279,6 +280,19 @@ func (u *UserInterface) setWindowSizeLimitsInDIP(minw, minh, maxw, maxh int) boo
 	return true
 }
 
+func (u *UserInterface) isInitWindowKeepAspectRatio() bool {
+	u.m.RLock()
+	v := u.initWindowKeepAspectRatio
+	u.m.RUnlock()
+	return v
+}
+
+func (u *UserInterface) setInitWindowKeepAspectRatio(keep bool) {
+	u.m.Lock()
+	u.initWindowKeepAspectRatio = keep
+	u.m.Unlock()
+}
+
 func (u *UserInterface) isInitFullscreen() bool {
 	u.m.RLock()
 	v := u.initFullscreen
@@ -918,6 +932,9 @@ func (u *UserInterface) init() error {
 		u.window.Maximize()
 	}
 
+	keepAspectRatio := u.isInitWindowKeepAspectRatio()
+	u.window.SetKeepAspectRatio(keepAspectRatio)
+
 	u.window.Show()
 
 	if g, ok := Graphics().(interface{ SetWindow(uintptr) }); ok {
diff --git a/internal/ui/window_glfw.go b/internal/ui/window_glfw.go
index b22620e0d..c0c234167 100644
--- a/internal/ui/window_glfw.go
+++ b/internal/ui/window_glfw.go
@@ -227,6 +227,16 @@ func (w *Window) SetSizeLimits(minw, minh, maxw, maxh int) {
 	w.ui.t.Call(w.ui.updateWindowSizeLimits)
 }
 
+func (w *Window) SetKeepAspectRatio(keep bool) {
+	if !w.ui.isRunning() {
+		w.ui.setInitWindowKeepAspectRatio(keep)
+		return
+	}
+	w.ui.t.Call(func() {
+		w.ui.window.SetKeepAspectRatio(keep)
+	})
+}
+
 func (w *Window) SetIcon(iconImages []image.Image) {
 	// The icons are actually set at (*UserInterface).loop.
 	w.ui.setIconImages(iconImages)
diff --git a/internal/ui/window_null.go b/internal/ui/window_null.go
index 861f67c56..b3d1ce543 100644
--- a/internal/ui/window_null.go
+++ b/internal/ui/window_null.go
@@ -79,6 +79,9 @@ func (*Window) IsMinimized() bool {
 	return false
 }
 
+func (*Window) SetKeepAspectRatio(keep bool) {
+}
+
 func (*Window) SetIcon(iconImages []image.Image) {
 }
 
diff --git a/window.go b/window.go
index 67e0f0a0f..88fb9d1f6 100644
--- a/window.go
+++ b/window.go
@@ -72,6 +72,13 @@ func SetWindowResizable(resizable bool) {
 	ui.Get().Window().SetResizable(resizable)
 }
 
+// SetWindowKeepAspectRatio sets whether the window should keep its aspect ratio while resizing.
+func SetWindowKeepAspectRatio(keep bool) {
+	if w := ui.Get().Window(); w != nil {
+		w.SetKeepAspectRatio(keep)
+	}
+}
+
 // SetWindowTitle sets the title of the window.
 //
 // SetWindowTitle does nothing on browsers or mobiles.