Platform UI scaling (mbrlabs#200)

* Calculate UI auto scaling based on the OS platform

* Use default ui scale for linux or unknown OS's, Clamp with ui scalebox max and min for safety, Use both height and width to calculate appropriate min and max for ui

* Larger range for calculated ui min and max scales

* Remove uneccessary max function

* use original scaling method for linux

* update changelog

* Use default ui scale from config for smallest auto scale value on linux

* Use altered godot method for scaling ui automatically on linux

docs/changelog.md

@@ -16,6 +16,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Changed
 - Changing the application language does not require a restart now
 - Completed Spanish translation
+- Improved UI auto scaling, especially for Windows and OSX
 
 ## [0.5.0] - 2022-06-12
 

lorien/Main.gd

@@ -531,9 +531,31 @@ func _on_scale_changed() -> void:
 	var auto_scale: int = Settings.get_value(Settings.APPEARANCE_UI_SCALE_MODE, Config.DEFAULT_UI_SCALE_MODE)
 	var scale: float
 	match auto_scale:
-		Types.UIScale.AUTO:   scale = OS.get_screen_size().x / ProjectSettings.get_setting("display/window/size/width")
+		Types.UIScale.AUTO:   scale = _get_platform_ui_scale()
 		Types.UIScale.CUSTOM: scale = Settings.get_value(Settings.APPEARANCE_UI_SCALE, Config.DEFAULT_UI_SCALE)
+	scale = clamp(scale, _settings_dialog.get_min_ui_scale(), _settings_dialog.get_max_ui_scale())
 
 	_canvas.set_canvas_scale(scale)
 	get_tree().set_screen_stretch(SceneTree.STRETCH_MODE_DISABLED, SceneTree.STRETCH_ASPECT_IGNORE, Vector2(0,0), scale)
 	OS.min_window_size = Config.MIN_WINDOW_SIZE * scale
+
+# --------------------------------------------------------------------------------------------------
+func _get_platform_ui_scale() -> float:
+	var platform: String = OS.get_name()
+	var scale: float
+	match platform:
+		"OSX":     scale = OS.get_screen_scale()
+		"Windows": scale = OS.get_screen_dpi() / 96.0
+		_:         scale = _get_general_ui_scale()
+	return scale
+
+# --------------------------------------------------------------------------------------------------
+func _get_general_ui_scale() -> float:
+	# Adapted from Godot EditorSettings::get_auto_display_scale()
+	# https://github.com/godotengine/godot/blob/3.x/editor/editor_settings.cpp
+	var smallest_dimension: int = min(OS.get_screen_size().x, OS.get_screen_size().y)
+	if OS.get_screen_dpi() >= 192 && smallest_dimension >= 1400:
+		return Config.DEFAULT_UI_SCALE * 2
+	elif smallest_dimension >= 1700:
+		return Config.DEFAULT_UI_SCALE * 1.5
+	return Config.DEFAULT_UI_SCALE

lorien/UI/Dialogs/SettingsDialog.gd

@@ -113,9 +113,18 @@ func _set_languages(current_locale: String) -> void:
 
 #--------------------------------------------------------------------------------------------------
 func _set_UIScale_range():
-	var screen_scale: float = OS.get_screen_size().x / ProjectSettings.get_setting("display/window/size/width")
-	_ui_scale.min_value = screen_scale / 2
-	_ui_scale.max_value = screen_scale + 1.5
+	var screen_scale_max: float = (OS.get_screen_size().x * OS.get_screen_size().y) / (ProjectSettings.get_setting("display/window/size/width") * ProjectSettings.get_setting("display/window/size/height"))
+	var screen_scale_min: float = OS.get_screen_size().x / ProjectSettings.get_setting("display/window/size/width")
+	_ui_scale.min_value = max(screen_scale_min / 2, 0.5)
+	_ui_scale.max_value = screen_scale_max + 1.5
+
+#--------------------------------------------------------------------------------------------------
+func get_max_ui_scale() -> float:
+	return _ui_scale.max_value
+
+#--------------------------------------------------------------------------------------------------
+func get_min_ui_scale() -> float:
+	return _ui_scale.min_value
 
 # -------------------------------------------------------------------------------------------------
 func _on_DefaultBrushSize_value_changed(value: int) -> void: