From 6d8462674f765dfbcc357ff50c57f5459aa1d64c Mon Sep 17 00:00:00 2001
From: Thierry Crozat <criezy@scummvm.org>
Date: Mon, 12 Jul 2021 13:36:11 +0100
Subject: [PATCH] COMMON: Add getHiDPIScreenFactor to OSystem

---
 backends/graphics/graphics.h | 1 +
 backends/modular-backend.cpp | 4 ++++
 backends/modular-backend.h   | 2 ++
 common/system.h              | 6 ++++++
 4 files changed, 13 insertions(+)

diff --git a/backends/graphics/graphics.h b/backends/graphics/graphics.h
index 3b56f5138d6..3533a8bafee 100644
--- a/backends/graphics/graphics.h
+++ b/backends/graphics/graphics.h
@@ -101,6 +101,7 @@ public:
 	virtual void copyRectToOverlay(const void *buf, int pitch, int x, int y, int w, int h) = 0;
 	virtual int16 getOverlayHeight() const = 0;
 	virtual int16 getOverlayWidth() const = 0;
+	virtual float getHiDPIScreenFactor() const { return 1.0f; }
 
 	virtual bool showMouse(bool visible) = 0;
 	virtual void warpMouse(int x, int y) = 0;
diff --git a/backends/modular-backend.cpp b/backends/modular-backend.cpp
index 21992de2d0a..7950018d574 100644
--- a/backends/modular-backend.cpp
+++ b/backends/modular-backend.cpp
@@ -243,6 +243,10 @@ int16 ModularGraphicsBackend::getOverlayWidth() {
 	return _graphicsManager->getOverlayWidth();
 }
 
+float ModularGraphicsBackend::getHiDPIScreenFactor() const {
+	return _graphicsManager->getHiDPIScreenFactor();
+}
+
 bool ModularGraphicsBackend::showMouse(bool visible) {
 	return _graphicsManager->showMouse(visible);
 }
diff --git a/backends/modular-backend.h b/backends/modular-backend.h
index 0bde48e1893..2318bfc0eb4 100644
--- a/backends/modular-backend.h
+++ b/backends/modular-backend.h
@@ -114,6 +114,8 @@ public:
 	virtual int16 getOverlayHeight() override final;
 	virtual int16 getOverlayWidth() override final;
 
+	virtual float getHiDPIScreenFactor() const override final;
+
 	virtual bool showMouse(bool visible) override final;
 	virtual void warpMouse(int x, int y) override final;
 	virtual void setMouseCursor(const void *buf, uint w, uint h, int hotspotX, int hotspotY, uint32 keycolor, bool dontScale = false, const Graphics::PixelFormat *format = NULL) override final;
diff --git a/common/system.h b/common/system.h
index 4ef6825d097..e040ba1a648 100644
--- a/common/system.h
+++ b/common/system.h
@@ -1052,6 +1052,12 @@ public:
 	 */
 	virtual PaletteManager *getPaletteManager() = 0;
 
+	/**
+	 * Return the scale factor for HiDPI screens.
+	 * Returns 1 for non-HiDPI screens, or if HiDPI display is not supported by the backend.
+	 */
+	virtual float getHiDPIScreenFactor() const { return 1.0f; }
+
 	/**
 	 * Blit a bitmap to the virtual screen.
 	 *