Change how is Retina handled on iOS

CHANGES

@@ -12,7 +12,8 @@
 - Gdx.files.external on Android now uses app external storage - see wiki article File handling for more information
 - Improved text, cursor and selection rendering in TextArea.
 - API Addition: Added setProgrammaticChangeEvents, updateVisualValue, round methods to ProgressBar/Slider.
-- Keyboard events working on RoboVM on iOS 13.5 and up, uses same API as on other platforms
+- iOS: Keyboard events working on RoboVM on iOS 13.5 and up, uses same API as on other platforms
+- iOS: Changed how Retina/hdpi handled on iOS, see #3709
 - API Addition: Added AndroidLiveWallpaper.notifyColorsChanged() to communicate visually significant colors back to the wallpaper engine.
 - API Change: AssetManager invokes the loaded callback when an asset is unloaded from the load queue if the asset is already loaded.
 - GWT: changed audio backend to WebAudio API. Now working on mobiles, pitch implemented. Configuration change: preferFlash removed. When updating existing projects, you can remove the soundmanager js files from your webapp folder and the references to it from index.html

backends/gdx-backend-robovm/src/com/badlogic/gdx/backends/iosrobovm/DefaultIOSInput.java

@@ -808,16 +808,16 @@ private static class NSArrayExtensions extends NSExtensions {
 	private void toTouchEvents (long touches) {
 		long array = NSSetExtensions.allObjects(touches);
 		int length = (int)NSArrayExtensions.count(array);
+		final IOSScreenBounds screenBounds = app.getScreenBounds();
 		for (int i = 0; i < length; i++) {
 			long touchHandle = NSArrayExtensions.objectAtIndex$(array, i);
 			UITouch touch = UI_TOUCH_WRAPPER.wrap(touchHandle);
 			final int locX, locY;
 			// Get and map the location to our drawing space
 			{
-				CGPoint loc = touch.getLocationInView(touch.getWindow());
-				final CGRect bounds = app.getCachedBounds();
-				locX = (int)(loc.getX() * app.displayScaleFactor - bounds.getMinX());
-				locY = (int)(loc.getY() * app.displayScaleFactor - bounds.getMinY());
+				CGPoint loc = touch.getLocationInView(app.graphics.view);
+				locX = (int)(loc.getX() - screenBounds.x);
+				locY = (int)(loc.getY() - screenBounds.y);
 				// app.debug("IOSInput","pos= "+loc+"  bounds= "+bounds+" x= "+locX+" locY= "+locY);
 			}
 

backends/gdx-backend-robovm/src/com/badlogic/gdx/backends/iosrobovm/IOSApplication.java

@@ -32,14 +32,12 @@
 import org.robovm.apple.uikit.UIInterfaceOrientation;
 import org.robovm.apple.uikit.UIPasteboard;
 import org.robovm.apple.uikit.UIScreen;
-import org.robovm.apple.uikit.UIUserInterfaceIdiom;
 import org.robovm.apple.uikit.UIViewController;
 import org.robovm.apple.uikit.UIWindow;
 import org.robovm.rt.bro.Bro;
 
 import com.badlogic.gdx.Application;
 import com.badlogic.gdx.ApplicationListener;
-import com.badlogic.gdx.ApplicationLogger;
 import com.badlogic.gdx.Audio;
 import com.badlogic.gdx.Files;
 import com.badlogic.gdx.Gdx;
@@ -102,9 +100,9 @@ public void willTerminate (UIApplication application) {
 	ApplicationLogger applicationLogger;
 
 	/** The display scale factor (1.0f for normal; 2.0f to use retina coordinates/dimensions). */
-	float displayScaleFactor;
+	float pixelsPerPoint;
 
-	private CGRect lastScreenBounds = null;
+	private IOSScreenBounds lastScreenBounds = null;
 
 	Array<Runnable> runnables = new Array<Runnable>();
 	Array<Runnable> executedRunnables = new Array<Runnable>();
@@ -124,34 +122,15 @@ final boolean didFinishLaunching (UIApplication uiApp, UIApplicationLaunchOption
 		UIApplication.getSharedApplication().setIdleTimerDisabled(config.preventScreenDimming);
 
 		Gdx.app.debug("IOSApplication", "iOS version: " + UIDevice.getCurrentDevice().getSystemVersion());
-		// fix the scale factor if we have a retina device (NOTE: iOS screen sizes are in "points" not pixels by default!)
-
 		Gdx.app.debug("IOSApplication", "Running in " + (Bro.IS_64BIT ? "64-bit" : "32-bit") + " mode");
 
-		float scale = (float) UIScreen.getMainScreen().getNativeScale();
-		if (scale >= 2.0f) {
-			Gdx.app.debug("IOSApplication", "scale: " + scale);
-			if (UIDevice.getCurrentDevice().getUserInterfaceIdiom() == UIUserInterfaceIdiom.Pad) {
-				// it's an iPad!
-				displayScaleFactor = config.displayScaleLargeScreenIfRetina * scale;
-			} else {
-				// it's an iPod or iPhone
-				displayScaleFactor = config.displayScaleSmallScreenIfRetina * scale;
-			}
-		} else {
-			// no retina screen: no scaling!
-			if (UIDevice.getCurrentDevice().getUserInterfaceIdiom() == UIUserInterfaceIdiom.Pad) {
-				// it's an iPad!
-				displayScaleFactor = config.displayScaleLargeScreenIfNonRetina;
-			} else {
-				// it's an iPod or iPhone
-				displayScaleFactor = config.displayScaleSmallScreenIfNonRetina;
-			}
-		}
+		// iOS counts in "points" instead of pixels. Points are logical pixels
+		pixelsPerPoint = (float)UIScreen.getMainScreen().getNativeScale();
+		Gdx.app.debug("IOSApplication", "Pixels per point: " + pixelsPerPoint);
 
 		// setup libgdx
 		this.input = createInput();
-		this.graphics = createGraphics(scale);
+		this.graphics = createGraphics();
 		Gdx.gl = Gdx.gl20 = graphics.gl20;
 		Gdx.gl30 = graphics.gl30;
 		this.files = new IOSFiles();
@@ -177,8 +156,8 @@ protected IOSAudio createAudio (IOSApplicationConfiguration config) {
 		return new OALIOSAudio(config);
 	}
 
-	protected IOSGraphics createGraphics(float scale) {
-		 return new IOSGraphics(scale, this, config, input, config.useGL30);
+	protected IOSGraphics createGraphics() {
+		 return new IOSGraphics(this, config, input, config.useGL30);
 	}
 
 	protected IOSGraphics.IOSUIViewController createUIViewController (IOSGraphics graphics) {
@@ -201,11 +180,9 @@ public UIWindow getUIWindow () {
 		return uiWindow;
 	}
 
-	/** GL View spans whole screen, that is, even under the status bar. iOS can also rotate the screen, which is not handled
-	 * consistently over iOS versions. This method returns, in pixels, rectangle in which libGDX draws.
-	 *
-	 * @return dimensions of space we draw to, adjusted for device orientation */
-	protected CGRect getBounds () {
+	/** @see IOSScreenBounds for detailed explanation
+	 * @return logical dimensions of space we draw to, adjusted for device orientation */
+	protected IOSScreenBounds computeBounds () {
 		final CGRect screenBounds = UIScreen.getMainScreen().getBounds();
 		final CGRect statusBarFrame = uiApp.getStatusBarFrame();
 		final UIInterfaceOrientation statusBarOrientation = uiApp.getStatusBarOrientation();
@@ -220,34 +197,40 @@ protected CGRect getBounds () {
 		case LandscapeLeft:
 		case LandscapeRight:
 			if (screenHeight > screenWidth) {
-				debug("IOSApplication", "Switching reported width and height (w=" + screenWidth + " h=" + screenHeight + ")");
+				debug("IOSApplication", "Switching reported width and height (original was w=" + screenWidth + " h="
+							+ screenHeight + ")");
 				double tmp = screenHeight;
 				// noinspection SuspiciousNameCombination
 				screenHeight = screenWidth;
 				screenWidth = tmp;
 			}
 		}
 
-		// update width/height depending on display scaling selected
-		screenWidth *= displayScaleFactor;
-		screenHeight *= displayScaleFactor;
-
 		if (statusBarHeight != 0.0) {
 			debug("IOSApplication", "Status bar is visible (height = " + statusBarHeight + ")");
-			statusBarHeight *= displayScaleFactor;
 			screenHeight -= statusBarHeight;
 		} else {
 			debug("IOSApplication", "Status bar is not visible");
 		}
+		final int offsetX = 0;
+		final int offsetY = (int)Math.round(statusBarHeight);
+
+		final int width = (int)Math.round(screenWidth);
+		final int height = (int)Math.round(screenHeight);
+
+		final int backBufferWidth = (int)Math.round(screenWidth * pixelsPerPoint);
+		final int backBufferHeight = (int)Math.round(screenHeight * pixelsPerPoint);
 
-		debug("IOSApplication", "Total computed bounds are w=" + screenWidth + " h=" + screenHeight);
+		debug("IOSApplication", "Computed bounds are x=" + offsetX + " y=" + offsetY + " w=" + width + " h=" + height + " bbW= "
+					+ backBufferWidth + " bbH= " + backBufferHeight);
 
-		return lastScreenBounds = new CGRect(0.0, statusBarHeight, screenWidth, screenHeight);
+		return lastScreenBounds = new IOSScreenBounds(offsetX, offsetY, width, height, backBufferWidth, backBufferHeight);
 	}
 
-	protected CGRect getCachedBounds () {
+	/** @return area of screen in UIKit points on which libGDX draws, with 0,0 being upper left corner */
+	public IOSScreenBounds getScreenBounds () {
 		if (lastScreenBounds == null)
-			return getBounds();
+			return computeBounds();
 		else
 			return lastScreenBounds;
 	}

backends/gdx-backend-robovm/src/com/badlogic/gdx/backends/iosrobovm/IOSApplicationConfiguration.java

@@ -47,39 +47,6 @@ public class IOSApplicationConfiguration {
 	/** number of frames per second, 60 is default **/
 	public int preferredFramesPerSecond = 60;
 
-	/** Scale factor to use on large screens with retina display, i.e. iPad 3+ (has no effect on non-retina screens).
-	 * <ul>
-	 * <li>1.0 = no scaling (everything is in pixels)
-	 * <li>0.5 = LibGDX will behave as you would only have half the pixels. I.e. instead of 2048x1536 you will work in 1024x768.
-	 * This looks pixel perfect and will save you the trouble to create bigger graphics for the retina display.
-	 * <li>any other value: scales the screens according to your scale factor. A scale factor oof 0.75, 0.8, 1.2, 1.5 etc. works
-	 * very well without any artifacts!
-	 * </ul> */
-	public float displayScaleLargeScreenIfRetina = 1.0f;
-	/** Scale factor to use on small screens with retina display, i.e. iPhone 4+, iPod 4+ (has no effect on non-retina screens).
-	 * <ul>
-	 * <li>1.0 = no scaling (everything is in pixels)
-	 * <li>0.5 = LibGDX will behave as you would only have half the pixels. I.e. instead of 960x640 you will work in 480x320. This
-	 * looks pixel perfect and will save you the trouble to create bigger graphics for the retina display.
-	 * <li>any other value: scales the screens according to your scale factor. A scale factor of 0.75, 0.8, 1.2, 1.5 etc. works
-	 * very well without any artifacts!
-	 * </ul> */
-	public float displayScaleSmallScreenIfRetina = 1.0f;
-	/** Scale factor to use on large screens without retina display, i.e. iPad 1+2 (has no effect on retina screens).
-	 * <ul>
-	 * <li>1.0 = no scaling (everything is in pixels)
-	 * <li>any other value: scales the screens according to your scale factor. A scale factor of 0.75, 0.8, 1.2, 1.5 etc. works
-	 * very well without any artifacts!
-	 * </ul> */
-	public float displayScaleLargeScreenIfNonRetina = 1.0f;
-	/** Scale factor to use on small screens without retina display, i.e. iPhone 1-3, iPod 1-3 (has no effect on retina screens).
-	 * <ul>
-	 * <li>1.0 = no scaling (everything is in pixels)
-	 * <li>any other value: scales the screens according to your scale factor. A scale factor of 0.75, 0.8, 1.2, 1.5 etc. works
-	 * very well without any artifacts!
-	 * </ul> */
-	public float displayScaleSmallScreenIfNonRetina = 1.0f;
-
 	/** whether to use the accelerometer, default true **/
 	public boolean useAccelerometer = true;
 	/** the update interval to poll the accelerometer with, in seconds **/

backends/gdx-backend-robovm/src/com/badlogic/gdx/backends/iosrobovm/IOSGraphics.java

@@ -65,7 +65,6 @@ public class IOSGraphics extends NSObject implements Graphics, GLKViewDelegate,
 	public static class IOSUIViewController extends GLKViewController {
 		final IOSApplication app;
 		final IOSGraphics graphics;
-		boolean created = false;
 
 		protected IOSUIViewController (IOSApplication app, IOSGraphics graphics) {
 			this.app = app;
@@ -124,14 +123,16 @@ public UIRectEdge getPreferredScreenEdgesDeferringSystemGestures() {
 		public void viewDidLayoutSubviews () {
 			super.viewDidLayoutSubviews();
 			// get the view size and update graphics
-			CGRect bounds = app.getBounds();
-			graphics.width = (int)bounds.getWidth();
-			graphics.height = (int)bounds.getHeight();
-			graphics.makeCurrent();
-			if (graphics.created) {
+			final IOSScreenBounds oldBounds = graphics.screenBounds;
+			final IOSScreenBounds newBounds = app.computeBounds();
+			graphics.screenBounds = newBounds;
+			// Layout may happen without bounds changing, don't trigger resize in that case
+			if (graphics.created && (newBounds.width != oldBounds.width || newBounds.height != oldBounds.height)) {
+				graphics.makeCurrent();
 				graphics.updateSafeInsets();
-				app.listener.resize(graphics.width, graphics.height);
+				app.listener.resize(newBounds.width, newBounds.height);
 			}
+
 		}
 
 		@Override
@@ -166,19 +167,11 @@ public void pressesEnded(NSSet<UIPress> presses, UIPressesEvent event) {
         }
 	}
 
-	static class IOSUIView extends GLKView {
-
-		public IOSUIView (CGRect frame, EAGLContext context) {
-			super(frame, context);
-		}
-	}
-
 	IOSApplication app;
 	IOSInput input;
 	GL20 gl20;
 	GL30 gl30;
-	int width;
-	int height;
+	IOSScreenBounds screenBounds;
 	int safeInsetLeft, safeInsetTop, safeInsetBottom, safeInsetRight;
 	long lastFrameTime;
 	float deltaTime;
@@ -205,13 +198,11 @@ public IOSUIView (CGRect frame, EAGLContext context) {
 	GLKView view;
 	IOSUIViewController viewController;
 
-	public IOSGraphics (float scale, IOSApplication app, IOSApplicationConfiguration config, IOSInput input, boolean useGLES30) {
+	public IOSGraphics (IOSApplication app, IOSApplicationConfiguration config, IOSInput input, boolean useGLES30) {
 		this.config = config;
 
-		final CGRect bounds = app.getBounds();
 		// setup view and OpenGL
-		width = (int)bounds.getWidth();
-		height = (int)bounds.getHeight();
+		screenBounds = app.computeBounds();
 
 		if (useGLES30) {
 			context = new EAGLContext(EAGLRenderingAPI.OpenGLES3);
@@ -226,7 +217,7 @@ public IOSGraphics (float scale, IOSApplication app, IOSApplicationConfiguration
 			gl30 = null;
 		}
 
-		view = new GLKView(new CGRect(0, 0, bounds.getWidth(), bounds.getHeight()), context) {
+		view = new GLKView(new CGRect(0, 0, screenBounds.width, screenBounds.height), context) {
 			@Method(selector = "touchesBegan:withEvent:")
 			public void touchesBegan (@Pointer long touches, UIEvent event) {
 				IOSGraphics.this.input.onTouch(touches);
@@ -296,7 +287,7 @@ public void draw (CGRect rect) {
 		IOSDevice device = config.knownDevices.get(machineString);
 		if (device == null) app.error(tag, "Machine ID: " + machineString + " not found, please report to LibGDX");
 		int ppi = device != null ? device.ppi : 163;
-		density = device != null ? device.ppi/160f : scale;
+		density = device != null ? device.ppi/160f : app.pixelsPerPoint;
 		ppiX = ppi;
 		ppiY = ppi;
 		ppcX = ppiX / 2.54f;
@@ -346,6 +337,8 @@ public void draw (GLKView view, CGRect rect) {
 		gl20.glViewport(IOSGLES20.x, IOSGLES20.y, IOSGLES20.width, IOSGLES20.height);
 
 		if (!created) {
+			final int width = screenBounds.width;
+			final int height = screenBounds.height;
 			gl20.glViewport(0, 0, width, height);
 
 			String versionString = gl20.glGetString(GL20.GL_VERSION);
@@ -437,22 +430,27 @@ public void setGL30 (GL30 gl30) {
 
 	@Override
 	public int getWidth () {
-		return width;
+		return screenBounds.width;
 	}
 
 	@Override
 	public int getHeight () {
-		return height;
+		return screenBounds.height;
 	}
 
 	@Override
 	public int getBackBufferWidth() {
-		return width;
+		return screenBounds.backBufferWidth;
 	}
 
 	@Override
 	public int getBackBufferHeight() {
-		return height;
+		return screenBounds.backBufferHeight;
+	}
+
+	/** @return amount of pixels per point */
+	public float getBackBufferScale() {
+		return app.pixelsPerPoint;
 	}
 
 	@Override

backends/gdx-backend-robovm/src/com/badlogic/gdx/backends/iosrobovm/IOSScreenBounds.java

@@ -0,0 +1,42 @@
+
+package com.badlogic.gdx.backends.iosrobovm;
+
+/** Represents the bounds inside GL view to which libGDX draws. These bounds may be same as view's dimensions, but may differ in
+ * some cases:
+ * <ul>
+ * <li>Status bar is visible - drawing area is not under the status bar</li>
+ * <li>Screen is rotated - in some iOS versions the rotation reporting behavior is different and this needs to be handled</li>
+ * </ul>
+ *
+ * <h3>IMPLEMENTATION & WARNING - Read carefully</h3> Accounting for status bar is not completely clean and relies on a
+ * coincidence, related to coordinate system origins. When status bar is present, x and y grows (in practice only y does) to
+ * offset the drawing area from the status bar and width and height (and their backBuffer values of course) shrink so the
+ * remaining surface fits the rest of the screen.
+ *
+ * When touch events arrive, IOSInput subtracts x and y from their coordinates to account for the shift.
+ *
+ * The unclean part is in the actual rendering - since the offset is essentially faked, there is no way to supply it to the libGDX
+ * application. But this does not become a problem, as long as Y and HEIGHT add up to the GL view's height (or X and WIDTH,
+ * although that is not used in practice), because GL's coordinate system (as far as the glViewport is concerned) starts in the
+ * LOWER left corner. So in practice, the rendering part of libGDX can be completely oblivious to any x/y offsets.
+ *
+ * This may become a problem when interfacing with UIKit, for example when placing banner ADs or using UIKit views over the
+ * libGDX's GL view. In such case, overriding {@link IOSApplication#computeBounds()} and providing custom, correct values is
+ * recommended. */
+public final class IOSScreenBounds {
+	/** Offset from top left corner in points */
+	public final int x, y;
+	/** Dimensions of drawing surface in points */
+	public final int width, height;
+	/** Dimensions of drawing surface in pixels */
+	public final int backBufferWidth, backBufferHeight;
+
+	public IOSScreenBounds (int x, int y, int width, int height, int backBufferWidth, int backBufferHeight) {
+		this.x = x;
+		this.y = y;
+		this.width = width;
+		this.height = height;
+		this.backBufferWidth = backBufferWidth;
+		this.backBufferHeight = backBufferHeight;
+	}
+}