Bug 1120 - Refine HiDPI Support ( Part-2 ) (API CHANGE)

- Use float[2] for pixel-scale.
  Utilize simple integer rounding:
    int-pixel-units = (int) ( int-window-units * pixel-scale + 0.5f )

- Provide minimum and maximum allowed pixel-scale values
  to be set by platform, supporting generic pixel-scale validation.

- Remove 'OSXUtil.GetPixelScale(final RectangleImmutable r, final int[] screenIndexOut)',
  implementation for all platforms would cause huge redundancy of
  Screen and MonitorDevice code (duplication of NEWT).

- instead, add 'float[2] pixelScale' to NEWT's MonitorDevice

- Detect change of pixel-scale and propagate accordingly.
  This allows GLCanvas, GLJPanel and NewtCanvasAWT instances
  to be dragged between monitor devices w/ different pixel-scale.

- OSX: Handle native triggered reshape events off-thread to avoid EDT congestion
       due to locked window when consuming deferred events on EDT.

22 files changed, 300 insertions, 146 deletions

diff --git a/src/newt/classes/com/jogamp/newt/MonitorDevice.java b/src/newt/classes/com/jogamp/newt/MonitorDevice.java
index 126162006..1a3222c71 100644
--- a/src/newt/classes/com/jogamp/newt/MonitorDevice.java
+++ b/src/newt/classes/com/jogamp/newt/MonitorDevice.java
@@ -30,6 +30,7 @@ package com.jogamp.newt;
 
 import java.util.List;
 
+import javax.media.nativewindow.ScalableSurface;
 import javax.media.nativewindow.util.DimensionImmutable;
 import javax.media.nativewindow.util.Rectangle;
 import javax.media.nativewindow.util.RectangleImmutable;
@@ -51,6 +52,7 @@ import com.jogamp.common.util.ArrayHashSet;
  *   <ul>
  *     <li>{@link MonitorMode} current mode</li>
  *     <li>{@link RectangleImmutable} viewport (rotated)</li>
+ *     <li>pixel-scale (rotated)</li>
  *   </ul></li>
  * </ul>
  * <p>
@@ -65,16 +67,31 @@ public abstract class MonitorDevice {
     protected final ArrayHashSet<MonitorMode> supportedModes; // FIXME: May need to support mutable mode, i.e. adding modes on the fly!
     protected MonitorMode currentMode;
     protected boolean modeChanged;
-    protected Rectangle viewportPU; // in pixel units
-    protected Rectangle viewportWU; // in window units
+    protected final float[] pixelScale;
+    protected final Rectangle viewportPU; // in pixel units
+    protected final Rectangle viewportWU; // in window units
 
-    protected MonitorDevice(final Screen screen, final int nativeId, final DimensionImmutable sizeMM, final Rectangle viewportPU, final Rectangle viewportWU, final MonitorMode currentMode, final ArrayHashSet<MonitorMode> supportedModes) {
+    /**
+     * @param screen associated {@link Screen}
+     * @param nativeId unique monitor device ID
+     * @param sizeMM size in millimeters
+     * @param currentMode
+     * @param pixelScale pre-fetched current pixel-scale, maybe {@code null} for {@link ScalableSurface#IDENTITY_PIXELSCALE}.
+     * @param viewportPU viewport in pixel-units
+     * @param viewportWU viewport in window-units
+     * @param supportedModes all supported {@link MonitorMode}s
+     */
+    protected MonitorDevice(final Screen screen, final int nativeId, final DimensionImmutable sizeMM,
+                            final MonitorMode currentMode,
+                            final float[] pixelScale, final Rectangle viewportPU, final Rectangle viewportWU,
+                            final ArrayHashSet<MonitorMode> supportedModes) {
         this.screen = screen;
         this.nativeId = nativeId;
         this.sizeMM = sizeMM;
         this.originalMode = currentMode;
         this.supportedModes = supportedModes;
         this.currentMode = currentMode;
+        this.pixelScale = null != pixelScale ? pixelScale : new float[] { 1.0f, 1.0f };
         this.viewportPU = viewportPU;
         this.viewportWU = viewportWU;
         this.modeChanged = false;
@@ -180,26 +197,40 @@ public abstract class MonitorDevice {
     }
 
     /**
-     * Returns the {@link RectangleImmutable rectangular} portion
+     * Returns the current {@link RectangleImmutable rectangular} portion
      * of the <b>rotated</b> virtual {@link Screen} size in pixel units
      * represented by this monitor, i.e. top-left origin and size.
-     * @see Screen
+     * @see #getPixelScale()
+     * @see Screen#getViewport()
      */
     public final RectangleImmutable getViewport() {
         return viewportPU;
     }
 
     /**
-     * Returns the {@link RectangleImmutable rectangular} portion
+     * Returns the current {@link RectangleImmutable rectangular} portion
      * of the <b>rotated</b> virtual {@link Screen} size in window units
      * represented by this monitor, i.e. top-left origin and size.
-     * @see Screen
+     * @see #getPixelScale()
+     * @see Screen#getViewportInWindowUnits()
      */
     public final RectangleImmutable getViewportInWindowUnits() {
         return viewportWU;
     }
 
     /**
+     * Returns the current <b>rotated</b> pixel-scale
+     * of this monitor, i.e. horizontal and vertical.
+     * @see #getViewportInWindowUnits()
+     * @see #getViewport()
+     * @see ScalableSurface#getMaximumSurfaceScale(float[])
+     */
+    public float[] getPixelScale(final float[] result) {
+        System.arraycopy(pixelScale, 0, result, 0, 2);
+        return result;
+    }
+
+    /**
      * Returns <code>true</code> if given screen coordinates in pixel units
      * are contained by this {@link #getViewport() viewport}, otherwise <code>false</code>.
      * @param x x-coord in pixel units
@@ -292,7 +323,8 @@ public abstract class MonitorDevice {
 
     @Override
     public String toString() {
-        return "Monitor[Id "+Display.toHexString(nativeId)+", "+sizeMM+" mm, viewport "+viewportPU+ " [pixels], "+viewportWU+" [window], orig "+originalMode+", curr "+currentMode+
+        return "Monitor[Id "+Display.toHexString(nativeId)+", "+sizeMM+" mm, pixelScale ["+pixelScale[0]+", "+pixelScale[1]+
+               "], viewport "+viewportPU+ " [pixels], "+viewportWU+" [window], orig "+originalMode+", curr "+currentMode+
                ", modeChanged "+modeChanged+", modeCount "+supportedModes.size()+"]";
     }
 }
diff --git a/src/newt/classes/com/jogamp/newt/Window.java b/src/newt/classes/com/jogamp/newt/Window.java
index c4ca9a554..7b7937c98 100644
--- a/src/newt/classes/com/jogamp/newt/Window.java
+++ b/src/newt/classes/com/jogamp/newt/Window.java
@@ -273,7 +273,7 @@ public interface Window extends NativeWindow, WindowClosingProtocol, ScalableSur
      * according to the {@link #getMainMonitor() main monitor}'s <i>current</i> {@link MonitorMode mode}'s
      * {@link SurfaceSize#getResolution() surface resolution}.
      * <p>
-     * Method takes the {@link #getCurrentSurfaceScale(int[]) current surface-scale} and {@link #getNativeSurfaceScale(int[]) native surface-scale}
+     * Method takes the {@link #getCurrentSurfaceScale(float[]) current surface-scale} and {@link #getMaximumSurfaceScale(float[]) native surface-scale}
      * into account, i.e.:
      * <pre>
      *    surfacePpMM = monitorPpMM * currentSurfaceScale / nativeSurfaceScale,
diff --git a/src/newt/classes/com/jogamp/newt/awt/NewtCanvasAWT.java b/src/newt/classes/com/jogamp/newt/awt/NewtCanvasAWT.java
index e890bc640..b469492c8 100644
--- a/src/newt/classes/com/jogamp/newt/awt/NewtCanvasAWT.java
+++ b/src/newt/classes/com/jogamp/newt/awt/NewtCanvasAWT.java
@@ -474,6 +474,13 @@ public class NewtCanvasAWT extends java.awt.Canvas implements WindowClosingProto
                 }
                 jawtWindow = NewtFactoryAWT.getNativeWindow(NewtCanvasAWT.this, null != newtChild ? newtChild.getRequestedCapabilities() : null);
                 jawtWindow.setShallUseOffscreenLayer(shallUseOffscreenLayer);
+                // enforce initial lock on AWT-EDT, allowing acquisition of pixel-scale
+                jawtWindow.lockSurface();
+                try {
+                    // attachNewtChild sets surface scale!
+                } finally {
+                    jawtWindow.unlockSurface();
+                }
                 awtWindowClosingProtocol.addClosingListener();
                 componentAdded = true; // Bug 910
                 if(DEBUG) {
@@ -486,6 +493,25 @@ public class NewtCanvasAWT extends java.awt.Canvas implements WindowClosingProto
             }
         }
     }
+    private final boolean updatePixelScale() {
+        if( jawtWindow.updatePixelScale(true) ) {
+            final Window cWin = newtChild;
+            final Window dWin = cWin.getDelegatedWindow();
+            if( dWin instanceof WindowImpl ) {
+                final float[] maxPixelScale = jawtWindow.getMaximumSurfaceScale(new float[2]);
+                final float[] minPixelScale = jawtWindow.getMinimumSurfaceScale(new float[2]);
+                ((WindowImpl)dWin).pixelScaleChangeNotify(minPixelScale, maxPixelScale, true);
+                // ((WindowImpl)dWin).sizeChangedNotify(true /* defer */, getWidth(), getHeight(), true /* force */);
+            } else {
+                final float[] reqPixelScale = jawtWindow.getRequestedSurfaceScale(new float[2]);
+                if( jawtWindow.setSurfaceScale(reqPixelScale) ) {
+                    // jawtWindow.getRequestedSurfaceScale(reqPixelScale);
+                }
+            }
+            return true;
+        }
+        return false;
+    }
 
     @Override
     public void removeNotify() {
@@ -588,7 +614,11 @@ public class NewtCanvasAWT extends java.awt.Canvas implements WindowClosingProto
                     System.err.println("NewtCanvasAWT.reshape: "+x+"/"+y+" "+width+"x"+height);
                 }
                 if( validateComponent(true) ) {
-                    // newtChild.setSize(width, height);
+                    if( !printActive && updatePixelScale() ) {
+                        // NOP
+                    } else {
+                        // newtChild.setSize(width, height);
+                    }
                 }
             }
         }
@@ -877,18 +907,12 @@ public class NewtCanvasAWT extends java.awt.Canvas implements WindowClosingProto
       }
       final int w = getWidth();
       final int h = getHeight();
-      final boolean isNValid = newtChild.isNativeValid();
       if(DEBUG) {
-          System.err.println("NewtCanvasAWT.attachNewtChild.2: size "+w+"x"+h+", isNValid "+isNValid);
+          System.err.println("NewtCanvasAWT.attachNewtChild.2: size "+w+"x"+h+", isNValid "+newtChild.isNativeValid());
       }
       newtChild.setVisible(false);
       newtChild.setSize(w, h);
-      final int[] reqSurfaceScale = new int[2];
-      if( isNValid ) {
-          newtChild.getCurrentSurfaceScale(reqSurfaceScale);
-      } else {
-          newtChild.getRequestedSurfaceScale(reqSurfaceScale);
-      }
+      final float[] reqSurfaceScale = newtChild.getRequestedSurfaceScale(new float[2]);
       jawtWindow.setSurfaceScale(reqSurfaceScale);
       newtChild.reparentWindow(jawtWindow, -1, -1, Window.REPARENT_HINT_BECOMES_VISIBLE);
       newtChild.addSurfaceUpdatedListener(jawtWindow);
diff --git a/src/newt/classes/com/jogamp/newt/opengl/GLWindow.java b/src/newt/classes/com/jogamp/newt/opengl/GLWindow.java
index 2ba030f76..0d286f25a 100644
--- a/src/newt/classes/com/jogamp/newt/opengl/GLWindow.java
+++ b/src/newt/classes/com/jogamp/newt/opengl/GLWindow.java
@@ -401,23 +401,28 @@ public class GLWindow extends GLAutoDrawableBase implements GLAutoDrawable, Wind
     }
 
     @Override
-    public final void setSurfaceScale(final int[] pixelScale) {
-        window.setSurfaceScale(pixelScale);
+    public final boolean setSurfaceScale(final float[] pixelScale) {
+        return window.setSurfaceScale(pixelScale);
     }
 
     @Override
-    public final int[] getRequestedSurfaceScale(final int[] result) {
+    public final float[] getRequestedSurfaceScale(final float[] result) {
         return window.getRequestedSurfaceScale(result);
     }
 
     @Override
-    public final int[] getCurrentSurfaceScale(final int[] result) {
+    public final float[] getCurrentSurfaceScale(final float[] result) {
         return window.getCurrentSurfaceScale(result);
     }
 
     @Override
-    public final int[] getNativeSurfaceScale(final int[] result) {
-        return window.getNativeSurfaceScale(result);
+    public final float[] getMinimumSurfaceScale(final float[] result) {
+        return window.getMinimumSurfaceScale(result);
+    }
+
+    @Override
+    public final float[] getMaximumSurfaceScale(final float[] result) {
+        return window.getMaximumSurfaceScale(result);
     }
 
     @Override
diff --git a/src/newt/classes/jogamp/newt/MonitorDeviceImpl.java b/src/newt/classes/jogamp/newt/MonitorDeviceImpl.java
index 72300740f..f1bd445ab 100644
--- a/src/newt/classes/jogamp/newt/MonitorDeviceImpl.java
+++ b/src/newt/classes/jogamp/newt/MonitorDeviceImpl.java
@@ -28,6 +28,7 @@
 
 package jogamp.newt;
 
+import javax.media.nativewindow.ScalableSurface;
 import javax.media.nativewindow.util.DimensionImmutable;
 import javax.media.nativewindow.util.Rectangle;
 
@@ -38,8 +39,21 @@ import com.jogamp.newt.Screen;
 
 public class MonitorDeviceImpl extends MonitorDevice {
 
-    public MonitorDeviceImpl(final ScreenImpl screen, final int nativeId, final DimensionImmutable sizeMM, final Rectangle viewportPU, final Rectangle viewportWU, final MonitorMode currentMode, final ArrayHashSet<MonitorMode> supportedModes) {
-        super(screen, nativeId, sizeMM, viewportPU, viewportWU, currentMode, supportedModes);
+    /**
+     * @param screen associated {@link Screen}
+     * @param nativeId unique monitor device ID
+     * @param sizeMM size in millimeters
+     * @param currentMode
+     * @param pixelScale pre-fetched current pixel-scale, maybe {@code null} for {@link ScalableSurface#IDENTITY_PIXELSCALE}.
+     * @param viewportPU viewport in pixel-units
+     * @param viewportWU viewport in window-units
+     * @param supportedModes all supported {@link MonitorMode}s
+     */
+    public MonitorDeviceImpl(final ScreenImpl screen, final int nativeId, final DimensionImmutable sizeMM,
+                             final MonitorMode currentMode,
+                             final float[] pixelScale, final Rectangle viewportPU, final Rectangle viewportWU,
+                             final ArrayHashSet<MonitorMode> supportedModes) {
+        super(screen, nativeId, sizeMM, currentMode, pixelScale, viewportPU, viewportWU, supportedModes);
     }
 
     @Override
diff --git a/src/newt/classes/jogamp/newt/MonitorModeProps.java b/src/newt/classes/jogamp/newt/MonitorModeProps.java
index 6e376ce48..6ed3b2382 100644
--- a/src/newt/classes/jogamp/newt/MonitorModeProps.java
+++ b/src/newt/classes/jogamp/newt/MonitorModeProps.java
@@ -33,6 +33,7 @@ import com.jogamp.newt.MonitorDevice;
 import com.jogamp.newt.MonitorMode;
 
 import java.util.List;
+import javax.media.nativewindow.ScalableSurface;
 import javax.media.nativewindow.util.Dimension;
 import javax.media.nativewindow.util.DimensionImmutable;
 import javax.media.nativewindow.util.Rectangle;
@@ -256,14 +257,19 @@ public class MonitorModeProps {
      * <p>
      * Note: This variant only works for impl. w/ a unique mode key pair <i>modeId, rotation</i>.
      * </p>
-     * @param mode_idx if not null, returns the index of resulting {@link MonitorDevice} within {@link Cache#monitorDevices}.
      * @param cache hash arrays of unique {@link MonitorMode} components and {@link MonitorDevice}s, allowing to avoid duplicates
-     * @param modeProperties the input data
+     * @param screen the associated {@link ScreenImpl}
+     * @param pixelScale pre-fetched current pixel-scale, maybe {@code null} for {@link ScalableSurface#IDENTITY_PIXELSCALE}.
+     * @param monitorProperties the input data minus supported modes!
      * @param offset the offset to the input data
+     * @param monitor_idx if not null, returns the index of resulting {@link MonitorDevice} within {@link Cache#monitorDevices}.
      * @return {@link MonitorDevice} of the identical (old or new) element in {@link Cache#monitorDevices},
      *         matching the input <code>modeProperties</code>, or null if input could not be processed.
      */
-    public static MonitorDevice streamInMonitorDevice(final int[] monitor_idx, final Cache cache, final ScreenImpl screen, final int[] monitorProperties, int offset) {
+    public static MonitorDevice streamInMonitorDevice(final Cache cache, final ScreenImpl screen,
+                                                      final float[] pixelScale,
+                                                      final int[] monitorProperties, int offset,
+                                                      final int[] monitor_idx) {
         // min 11: count, id, ScreenSizeMM[width, height], Viewport[x, y, width, height], currentMonitorModeId, rotation, supportedModeId+
         final int count = monitorProperties[offset];
         if(MIN_MONITOR_DEVICE_PROPERTIES > count) {
@@ -298,7 +304,7 @@ public class MonitorModeProps {
                 }
             }
         }
-        MonitorDevice monitorDevice = new MonitorDeviceImpl(screen, id, sizeMM, viewportPU, viewportWU, currentMode, supportedModes);
+        MonitorDevice monitorDevice = new MonitorDeviceImpl(screen, id, sizeMM, currentMode, pixelScale, viewportPU, viewportWU, supportedModes);
         if(null!=cache) {
             monitorDevice = cache.monitorDevices.getOrAdd(monitorDevice);
         }
@@ -329,17 +335,23 @@ public class MonitorModeProps {
      * This variant expects <code>count</code> to be <code>{@link MIN_MONITOR_DEVICE_PROPERTIES} - 1 - {@link NUM_MONITOR_MODE_PROPERTIES}</code>,
      * due to lack of supported mode and current mode.
      * </p>
-     *
-     * @param mode_idx if not null, returns the index of resulting {@link MonitorDevice} within {@link Cache#monitorDevices}.
      * @param cache hash arrays of unique {@link MonitorMode} components and {@link MonitorDevice}s, allowing to avoid duplicates
-     * @param supportedModes pre-assembled list of supported {@link MonitorMode}s from cache.
+     * @param screen the associated {@link ScreenImpl}
      * @param currentMode pre-fetched current {@link MonitorMode}s from cache.
-     * @param modeProperties the input data minus supported modes!
+     * @param pixelScale pre-fetched current pixel-scale, maybe {@code null} for {@link ScalableSurface#IDENTITY_PIXELSCALE}.
+     * @param supportedModes pre-assembled list of supported {@link MonitorMode}s from cache.
+     * @param monitorProperties the input data minus supported modes!
      * @param offset the offset to the input data
+     * @param monitor_idx if not null, returns the index of resulting {@link MonitorDevice} within {@link Cache#monitorDevices}.
      * @return {@link MonitorDevice} of the identical (old or new) element in {@link Cache#monitorDevices},
      *         matching the input <code>modeProperties</code>, or null if input could not be processed.
      */
-    public static MonitorDevice streamInMonitorDevice(final int[] monitor_idx, final Cache cache, final ScreenImpl screen, final ArrayHashSet<MonitorMode> supportedModes, final MonitorMode currentMode, final int[] monitorProperties, int offset) {
+    public static MonitorDevice streamInMonitorDevice(final Cache cache, final ScreenImpl screen,
+                                                      final MonitorMode currentMode,
+                                                      final float[] pixelScale,
+                                                      final ArrayHashSet<MonitorMode> supportedModes,
+                                                      final int[] monitorProperties, int offset,
+                                                      final int[] monitor_idx) {
         // min 11: count, id, ScreenSizeMM[width, height], Viewport[x, y, width, height], currentMonitorModeId, rotation, supportedModeId+
         final int count = monitorProperties[offset];
         if(MIN_MONITOR_DEVICE_PROPERTIES - 1 - NUM_MONITOR_MODE_PROPERTIES != count) {
@@ -356,7 +368,7 @@ public class MonitorModeProps {
         final DimensionImmutable sizeMM = streamInResolution(monitorProperties, offset); offset+=NUM_RESOLUTION_PROPERTIES;
         final Rectangle viewportPU = new Rectangle(monitorProperties[offset++], monitorProperties[offset++], monitorProperties[offset++], monitorProperties[offset++]);
         final Rectangle viewportWU = new Rectangle(monitorProperties[offset++], monitorProperties[offset++], monitorProperties[offset++], monitorProperties[offset++]);
-        MonitorDevice monitorDevice = new MonitorDeviceImpl(screen, id, sizeMM, viewportPU, viewportWU, currentMode, supportedModes);
+        MonitorDevice monitorDevice = new MonitorDeviceImpl(screen, id, sizeMM, currentMode, pixelScale, viewportPU, viewportWU, supportedModes);
         if(null!=cache) {
             monitorDevice = cache.monitorDevices.getOrAdd(monitorDevice);
         }
diff --git a/src/newt/classes/jogamp/newt/ScreenImpl.java b/src/newt/classes/jogamp/newt/ScreenImpl.java
index e73e153ad..c57f84528 100644
--- a/src/newt/classes/jogamp/newt/ScreenImpl.java
+++ b/src/newt/classes/jogamp/newt/ScreenImpl.java
@@ -364,8 +364,8 @@ public abstract class ScreenImpl extends Screen implements MonitorModeListener {
      *   <li>{@link MonitorModeProps#MIN_MONITOR_DEVICE_PROPERTIES}</li>
      * </ul>, i.e.
      * <ul>
-     *   <li>{@link MonitorModeProps#streamInMonitorDevice(int[], jogamp.newt.MonitorModeProps.Cache, ScreenImpl, int[], int)}</li>
-     *   <li>{@link MonitorModeProps#streamInMonitorDevice(int[], jogamp.newt.MonitorModeProps.Cache, ScreenImpl, ArrayHashSet, int[], int)}</li>
+     *   <li>{@link MonitorModeProps#streamInMonitorDevice(jogamp.newt.MonitorModeProps.Cache, ScreenImpl, double[], int[], int, int[])}</li>
+     *   <li>{@link MonitorModeProps#streamInMonitorDevice(int[], jogamp.newt.MonitorModeProps.Cache, ArrayHashSet, int[], int, ScreenImpl)}</li>
      *   <li>{@link MonitorModeProps#streamInMonitorMode(int[], jogamp.newt.MonitorModeProps.Cache, int[], int)}</li>
      * </ul>
      * @param cache memory pool caching the result
@@ -373,6 +373,7 @@ public abstract class ScreenImpl extends Screen implements MonitorModeListener {
     protected abstract void collectNativeMonitorModesAndDevicesImpl(MonitorModeProps.Cache cache);
 
     protected boolean updateNativeMonitorDeviceViewportImpl(final MonitorDevice monitor,
+                                                            final float[] pixelScale,
                                                             final Rectangle viewportPU, final Rectangle viewportWU) {
         return false;
     }
@@ -428,9 +429,14 @@ public abstract class ScreenImpl extends Screen implements MonitorModeListener {
         final List<MonitorDevice> monitors = getMonitorDevices();
         for(int i=monitors.size()-1; i>=0; i--) {
             final MonitorDeviceImpl monitor = (MonitorDeviceImpl) monitors.get(i);
-            final boolean viewportUpdated = updateNativeMonitorDeviceViewportImpl(monitor, monitor.getMutuableViewportPU(), monitor.getMutuableViewportWU());
+            final float[] pixelScale = monitor.getPixelScale(new float[2]);
+            final boolean viewportUpdated = updateNativeMonitorDeviceViewportImpl(monitor, pixelScale,
+                                                                                  monitor.getMutuableViewportPU(),
+                                                                                  monitor.getMutuableViewportWU());
             if( DEBUG ) {
-                System.err.println("Screen.updateMonitorViewport["+i+"] @  "+Thread.currentThread().getName()+": updated: "+viewportUpdated+", PU "+monitor.getViewport()+", WU "+monitor.getViewportInWindowUnits());
+                System.err.println("Screen.updateMonitorViewport["+i+"] @  "+Thread.currentThread().getName()+": updated: "+viewportUpdated+
+                                   ", PU "+monitor.getViewport()+", WU "+monitor.getViewportInWindowUnits()+
+                                   ", pixelScale ["+pixelScale[0]+", "+pixelScale[1]+"]");
             }
         }
     }
@@ -510,7 +516,7 @@ public abstract class ScreenImpl extends Screen implements MonitorModeListener {
         if( MonitorModeProps.MIN_MONITOR_DEVICE_PROPERTIES != i ) {
             throw new InternalError("XX");
         }
-        return MonitorModeProps.streamInMonitorDevice(null, cache, this, props, 0);
+        return MonitorModeProps.streamInMonitorDevice(cache, this, null, props, 0, null);
     }
 
     /**
diff --git a/src/newt/classes/jogamp/newt/WindowImpl.java b/src/newt/classes/jogamp/newt/WindowImpl.java
index 0c4dcd192..2230acd67 100644
--- a/src/newt/classes/jogamp/newt/WindowImpl.java
+++ b/src/newt/classes/jogamp/newt/WindowImpl.java
@@ -154,9 +154,10 @@ public abstract class WindowImpl implements Window, NEWTEventConsumer
     private volatile boolean hasFocus = false;
     private volatile int pixWidth = 128, pixHeight = 128; // client-area size w/o insets in pixel units, default: may be overwritten by user
     private volatile int winWidth = 128, winHeight = 128; // client-area size w/o insets in window units, default: may be overwritten by user
-    protected final int[] nativePixelScale = new int[] { ScalableSurface.IDENTITY_PIXELSCALE, ScalableSurface.IDENTITY_PIXELSCALE };
-    protected final int[] hasPixelScale = new int[] { ScalableSurface.IDENTITY_PIXELSCALE, ScalableSurface.IDENTITY_PIXELSCALE };
-    protected final int[] reqPixelScale = new int[] { ScalableSurface.AUTOMAX_PIXELSCALE, ScalableSurface.AUTOMAX_PIXELSCALE };
+    protected final float[] minPixelScale = new float[] { ScalableSurface.IDENTITY_PIXELSCALE, ScalableSurface.IDENTITY_PIXELSCALE };
+    protected final float[] maxPixelScale = new float[] { ScalableSurface.IDENTITY_PIXELSCALE, ScalableSurface.IDENTITY_PIXELSCALE };
+    protected final float[] hasPixelScale = new float[] { ScalableSurface.IDENTITY_PIXELSCALE, ScalableSurface.IDENTITY_PIXELSCALE };
+    protected final float[] reqPixelScale = new float[] { ScalableSurface.AUTOMAX_PIXELSCALE, ScalableSurface.AUTOMAX_PIXELSCALE };
 
     private volatile int x = 64, y = 64; // client-area pos w/o insets in window units
     private volatile Insets insets = new Insets(); // insets of decoration (if top-level && decorated)
@@ -1087,8 +1088,8 @@ public abstract class WindowImpl implements Window, NEWTEventConsumer
     }
     @Override
     public final void setSurfaceSize(final int pixelWidth, final int pixelHeight) {
-        // FIXME HiDPI: Shortcut, may need to adjust if we change scaling methodology
-        setSize(pixelWidth / getPixelScaleX(), pixelHeight / getPixelScaleY());
+        setSize( SurfaceScaleUtils.scaleInv(pixelWidth, getPixelScaleX()),
+                 SurfaceScaleUtils.scaleInv(pixelHeight, getPixelScaleY()) );
     }
     @Override
     public final void setTopLevelSize(final int width, final int height) {
@@ -1181,8 +1182,10 @@ public abstract class WindowImpl implements Window, NEWTEventConsumer
                 parentWindowHandle = 0;
                 hasPixelScale[0] = ScalableSurface.IDENTITY_PIXELSCALE;
                 hasPixelScale[1] = ScalableSurface.IDENTITY_PIXELSCALE;
-                nativePixelScale[0] = ScalableSurface.IDENTITY_PIXELSCALE;
-                nativePixelScale[1] = ScalableSurface.IDENTITY_PIXELSCALE;
+                minPixelScale[0] = ScalableSurface.IDENTITY_PIXELSCALE;
+                minPixelScale[1] = ScalableSurface.IDENTITY_PIXELSCALE;
+                maxPixelScale[0] = ScalableSurface.IDENTITY_PIXELSCALE;
+                maxPixelScale[1] = ScalableSurface.IDENTITY_PIXELSCALE;
 
                 _lock.unlock();
             }
@@ -1926,16 +1929,12 @@ public abstract class WindowImpl implements Window, NEWTEventConsumer
 
     @Override
     public final int[] convertToWindowUnits(final int[] pixelUnitsAndResult) {
-        pixelUnitsAndResult[0] /= getPixelScaleX();
-        pixelUnitsAndResult[1] /= getPixelScaleY();
-        return pixelUnitsAndResult;
+        return SurfaceScaleUtils.scaleInv(pixelUnitsAndResult, pixelUnitsAndResult, hasPixelScale);
     }
 
     @Override
     public final int[] convertToPixelUnits(final int[] windowUnitsAndResult) {
-        windowUnitsAndResult[0] *= getPixelScaleX();
-        windowUnitsAndResult[1] *= getPixelScaleY();
-        return windowUnitsAndResult;
+        return SurfaceScaleUtils.scale(windowUnitsAndResult, windowUnitsAndResult, hasPixelScale);
     }
 
     protected final Point convertToWindowUnits(final Point pixelUnitsAndResult) {
@@ -1947,43 +1946,50 @@ public abstract class WindowImpl implements Window, NEWTEventConsumer
     }
 
     /** HiDPI: We currently base scaling of window units to pixel units on an integer scale factor per component. */
-    protected final int getPixelScaleX() {
+    protected final float getPixelScaleX() {
         return hasPixelScale[0];
     }
 
     /** HiDPI: We currently base scaling of window units to pixel units on an integer scale factor per component. */
-    protected final int getPixelScaleY() {
+    protected final float getPixelScaleY() {
         return hasPixelScale[1];
     }
 
     @Override
-    public void setSurfaceScale(final int[] pixelScale) {
-        SurfaceScaleUtils.validateReqPixelScale(reqPixelScale, pixelScale, DEBUG_IMPLEMENTATION ? getClass().getSimpleName() : null);
+    public boolean setSurfaceScale(final float[] pixelScale) {
+        System.arraycopy(pixelScale, 0, reqPixelScale, 0, 2);
+        return false;
     }
 
     @Override
-    public final int[] getRequestedSurfaceScale(final int[] result) {
+    public final float[] getRequestedSurfaceScale(final float[] result) {
         System.arraycopy(reqPixelScale, 0, result, 0, 2);
         return result;
     }
 
     @Override
-    public final int[] getCurrentSurfaceScale(final int[] result) {
+    public final float[] getCurrentSurfaceScale(final float[] result) {
         System.arraycopy(hasPixelScale, 0, result, 0, 2);
         return result;
     }
 
     @Override
-    public final int[] getNativeSurfaceScale(final int[] result) {
-        System.arraycopy(nativePixelScale, 0, result, 0, 2);
+    public final float[] getMinimumSurfaceScale(final float[] result) {
+        System.arraycopy(minPixelScale, 0, result, 0, 2);
+        return result;
+    }
+
+    @Override
+    public final float[] getMaximumSurfaceScale(final float[] result) {
+        System.arraycopy(maxPixelScale, 0, result, 0, 2);
         return result;
     }
 
     @Override
     public final float[] getPixelsPerMM(final float[] ppmmStore) {
         getMainMonitor().getPixelsPerMM(ppmmStore);
-        ppmmStore[0] *= (float)hasPixelScale[0] / (float)nativePixelScale[0];
-        ppmmStore[1] *= (float)hasPixelScale[1] / (float)nativePixelScale[1];
+        ppmmStore[0] *= hasPixelScale[0] / maxPixelScale[0];
+        ppmmStore[1] *= hasPixelScale[1] / maxPixelScale[1];
         return ppmmStore;
     }
 
@@ -2004,8 +2010,9 @@ public abstract class WindowImpl implements Window, NEWTEventConsumer
      * and {@link #pixWidth} and {@link #pixHeight} in pixel units according to {@link #convertToPixelUnits(int[])}.
      */
     protected final void defineSize(final int winWidth, final int winHeight) {
-        final int pixWidth = winWidth * getPixelScaleX();   // FIXME HiDPI: Shortcut, may need to adjust if we change scaling methodology
-        final int pixHeight = winHeight * getPixelScaleY();
+        final int pixWidth = SurfaceScaleUtils.scale(winWidth, getPixelScaleX());   // FIXME HiDPI: Shortcut, may need to adjust if we change scaling methodology
+        final int pixHeight = SurfaceScaleUtils.scale(winHeight, getPixelScaleY());
+
         if(DEBUG_IMPLEMENTATION) {
             System.err.println("defineSize: win["+this.winWidth+"x"+this.winHeight+" -> "+winWidth+"x"+winHeight+
                                "], pixel["+this.pixWidth+"x"+this.pixHeight+" -> "+pixWidth+"x"+pixHeight+"]");
@@ -2631,13 +2638,13 @@ public abstract class WindowImpl implements Window, NEWTEventConsumer
             // special repaint treatment
             case WindowEvent.EVENT_WINDOW_REPAINT:
                 // queue repaint event in case window is locked, ie in operation
-                if( null != windowLock.getOwner() ) {
+                if( windowLock.isLockedByOtherThread() ) {
                     // make sure only one repaint event is queued
                     if(!repaintQueued) {
                         repaintQueued=true;
                         final boolean discardTO = QUEUED_EVENT_TO <= System.currentTimeMillis()-e.getWhen();
                         if(DEBUG_IMPLEMENTATION) {
-                            System.err.println("Window.consumeEvent: REPAINT "+Thread.currentThread().getName()+" - queued "+e+", discard-to "+discardTO);
+                            System.err.println("Window.consumeEvent: REPAINT [me "+Thread.currentThread().getName()+", owner "+windowLock.getOwner()+"] - queued "+e+", discard-to "+discardTO);
                             // ExceptionUtils.dumpStackTrace(System.err);
                         }
                         return discardTO; // discardTO:=true -> consumed
@@ -2650,10 +2657,10 @@ public abstract class WindowImpl implements Window, NEWTEventConsumer
             // common treatment
             case WindowEvent.EVENT_WINDOW_RESIZED:
                 // queue event in case window is locked, ie in operation
-                if( null != windowLock.getOwner() ) {
+                if( windowLock.isLockedByOtherThread() ) {
                     final boolean discardTO = QUEUED_EVENT_TO <= System.currentTimeMillis()-e.getWhen();
                     if(DEBUG_IMPLEMENTATION) {
-                        System.err.println("Window.consumeEvent: RESIZED "+Thread.currentThread().getName()+" - queued "+e+", discard-to "+discardTO);
+                        System.err.println("Window.consumeEvent: RESIZED [me "+Thread.currentThread().getName()+", owner "+windowLock.getOwner()+"] - queued "+e+", discard-to "+discardTO);
                         // ExceptionUtils.dumpStackTrace(System.err);
                     }
                     return discardTO; // discardTO:=true -> consumed
@@ -3756,6 +3763,21 @@ public abstract class WindowImpl implements Window, NEWTEventConsumer
         }
     }
 
+    /**
+     * Notify to update the pixel-scale values.
+     * @param minPixelScale
+     * @param maxPixelScale
+     * @param reset if {@code true} {@link #setSurfaceScale(float[]) reset pixel-scale} w/ {@link #getRequestedSurfaceScale(float[]) requested values}
+     *        value to reflect the new minimum and maximum values.
+     */
+    public final void pixelScaleChangeNotify(final float[] minPixelScale, final float[] maxPixelScale, final boolean reset) {
+        System.arraycopy(minPixelScale, 0, this.minPixelScale, 0, 2);
+        System.arraycopy(maxPixelScale, 0, this.maxPixelScale, 0, 2);
+        if( reset ) {
+            setSurfaceScale(reqPixelScale);
+        }
+    }
+
     /** Triggered by implementation's WM events to update the client-area size in window units w/o insets/decorations. */
     protected void sizeChanged(final boolean defer, final int newWidth, final int newHeight, final boolean force) {
         if(force || getWidth() != newWidth || getHeight() != newHeight) {
diff --git a/src/newt/classes/jogamp/newt/driver/android/ScreenDriver.java b/src/newt/classes/jogamp/newt/driver/android/ScreenDriver.java
index b28cdcbed..59688cd8d 100644
--- a/src/newt/classes/jogamp/newt/driver/android/ScreenDriver.java
+++ b/src/newt/classes/jogamp/newt/driver/android/ScreenDriver.java
@@ -113,7 +113,7 @@ public class ScreenDriver extends jogamp.newt.ScreenImpl {
         props[i++] = 0; // rotated viewport y window-units
         props[i++] = outMetrics.widthPixels; // rotated viewport width window-units
         props[i++] = outMetrics.heightPixels; // rotated viewport height window-units
-        MonitorModeProps.streamInMonitorDevice(null, cache, this, cache.monitorModes, currentMode, props, 0);
+        MonitorModeProps.streamInMonitorDevice(cache, this, currentMode, null, cache.monitorModes, props, 0, null);
     }
 
     @Override
diff --git a/src/newt/classes/jogamp/newt/driver/awt/AWTCanvas.java b/src/newt/classes/jogamp/newt/driver/awt/AWTCanvas.java
index eccdd63cf..76ae26764 100644
--- a/src/newt/classes/jogamp/newt/driver/awt/AWTCanvas.java
+++ b/src/newt/classes/jogamp/newt/driver/awt/AWTCanvas.java
@@ -69,8 +69,8 @@ public class AWTCanvas extends Canvas {
   private final UpstreamScalable upstreamScale;
 
   public static interface UpstreamScalable {
-      int[] getReqPixelScale();
-      void setHasPixelScale(final int[] pixelScale);
+      float[] getReqPixelScale();
+      void setHasPixelScale(final float[] pixelScale);
   }
 
   private boolean displayConfigChanged=false;
@@ -148,7 +148,7 @@ public class AWTCanvas extends Canvas {
         // trigger initialization cycle
         jawtWindow.setSurfaceScale(upstreamScale.getReqPixelScale() );
         jawtWindow.lockSurface();
-        upstreamScale.setHasPixelScale(jawtWindow.getCurrentSurfaceScale(new int[2]));
+        upstreamScale.setHasPixelScale(jawtWindow.getCurrentSurfaceScale(new float[2]));
         jawtWindow.unlockSurface();
     }
 
diff --git a/src/newt/classes/jogamp/newt/driver/awt/ScreenDriver.java b/src/newt/classes/jogamp/newt/driver/awt/ScreenDriver.java
index 57948cfc3..eb92e0d13 100644
--- a/src/newt/classes/jogamp/newt/driver/awt/ScreenDriver.java
+++ b/src/newt/classes/jogamp/newt/driver/awt/ScreenDriver.java
@@ -119,7 +119,7 @@ public class ScreenDriver extends ScreenImpl {
         props[i++] = 0; // rotated viewport y window-units
         props[i++] = currentMode.getRotatedWidth(); // rotated viewport width window-units
         props[i++] = currentMode.getRotatedHeight(); // rotated viewport height window-units
-        MonitorModeProps.streamInMonitorDevice(null, cache, this, cache.monitorModes, currentMode, props, 0);
+        MonitorModeProps.streamInMonitorDevice(cache, this, currentMode, null, cache.monitorModes, props, 0, null);
     }
 
     @Override
diff --git a/src/newt/classes/jogamp/newt/driver/awt/WindowDriver.java b/src/newt/classes/jogamp/newt/driver/awt/WindowDriver.java
index 06dcb8ff5..2ccc8d763 100644
--- a/src/newt/classes/jogamp/newt/driver/awt/WindowDriver.java
+++ b/src/newt/classes/jogamp/newt/driver/awt/WindowDriver.java
@@ -100,12 +100,12 @@ public class WindowDriver extends WindowImpl {
 
     private final AWTCanvas.UpstreamScalable upstreamScalable = new AWTCanvas.UpstreamScalable() {
         @Override
-        public int[] getReqPixelScale() {
+        public float[] getReqPixelScale() {
             return WindowDriver.this.reqPixelScale;
         }
 
         @Override
-        public void setHasPixelScale(final int[] pixelScale) {
+        public void setHasPixelScale(final float[] pixelScale) {
             System.arraycopy(pixelScale, 0, WindowDriver.this.hasPixelScale, 0, 2);
         }
     };
diff --git a/src/newt/classes/jogamp/newt/driver/bcm/egl/ScreenDriver.java b/src/newt/classes/jogamp/newt/driver/bcm/egl/ScreenDriver.java
index 2cd47313a..f3ac3e851 100644
--- a/src/newt/classes/jogamp/newt/driver/bcm/egl/ScreenDriver.java
+++ b/src/newt/classes/jogamp/newt/driver/bcm/egl/ScreenDriver.java
@@ -94,7 +94,7 @@ public class ScreenDriver extends jogamp.newt.ScreenImpl {
         props[i++] = 0; // rotated viewport y window-units
         props[i++] = fixedWidth; // FIXME rotated viewport width window-units
         props[i++] = fixedHeight; // FIXME rotated viewport height window-units
-        MonitorModeProps.streamInMonitorDevice(null, cache, this, cache.monitorModes, currentMode, props, 0);
+        MonitorModeProps.streamInMonitorDevice(cache, this, currentMode, null, cache.monitorModes, props, 0, null);
     }
 
     @Override
diff --git a/src/newt/classes/jogamp/newt/driver/bcm/vc/iv/ScreenDriver.java b/src/newt/classes/jogamp/newt/driver/bcm/vc/iv/ScreenDriver.java
index 64cae75f6..bc1c19fe4 100644
--- a/src/newt/classes/jogamp/newt/driver/bcm/vc/iv/ScreenDriver.java
+++ b/src/newt/classes/jogamp/newt/driver/bcm/vc/iv/ScreenDriver.java
@@ -87,7 +87,7 @@ public class ScreenDriver extends ScreenImpl {
         props[i++] = 0; // rotated viewport y window-units
         props[i++] = cachedWidth; // rotated viewport width window-units
         props[i++] = cachedWidth; // rotated viewport height window-units
-        MonitorModeProps.streamInMonitorDevice(null, cache, this, cache.monitorModes, currentMode, props, 0);
+        MonitorModeProps.streamInMonitorDevice(cache, this, currentMode, null, cache.monitorModes, props, 0, null);
     }
 
     @Override
diff --git a/src/newt/classes/jogamp/newt/driver/intel/gdl/ScreenDriver.java b/src/newt/classes/jogamp/newt/driver/intel/gdl/ScreenDriver.java
index 2ce835c52..36a95dca4 100644
--- a/src/newt/classes/jogamp/newt/driver/intel/gdl/ScreenDriver.java
+++ b/src/newt/classes/jogamp/newt/driver/intel/gdl/ScreenDriver.java
@@ -96,7 +96,7 @@ public class ScreenDriver extends jogamp.newt.ScreenImpl {
         props[i++] = 0; // rotated viewport y window-units
         props[i++] = cachedWidth; // rotated viewport width window-units
         props[i++] = cachedWidth; // rotated viewport height window-units
-        MonitorModeProps.streamInMonitorDevice(null, cache, this, cache.monitorModes, currentMode, props, 0);
+        MonitorModeProps.streamInMonitorDevice(cache, this, currentMode, null, cache.monitorModes, props, 0, null);
     }
 
     @Override
diff --git a/src/newt/classes/jogamp/newt/driver/kd/ScreenDriver.java b/src/newt/classes/jogamp/newt/driver/kd/ScreenDriver.java
index d4113561a..42659b14e 100644
--- a/src/newt/classes/jogamp/newt/driver/kd/ScreenDriver.java
+++ b/src/newt/classes/jogamp/newt/driver/kd/ScreenDriver.java
@@ -92,7 +92,7 @@ public class ScreenDriver extends ScreenImpl {
         props[i++] = 0; // rotated viewport y window-units
         props[i++] = cachedWidth; // rotated viewport width window-units
         props[i++] = cachedWidth; // rotated viewport height window-units
-        MonitorModeProps.streamInMonitorDevice(null, cache, this, cache.monitorModes, currentMode, props, 0);
+        MonitorModeProps.streamInMonitorDevice(cache, this, currentMode, null, cache.monitorModes, props, 0, null);
     }
 
     @Override
diff --git a/src/newt/classes/jogamp/newt/driver/macosx/ScreenDriver.java b/src/newt/classes/jogamp/newt/driver/macosx/ScreenDriver.java
index 5f458e2c9..7c4fa569a 100644
--- a/src/newt/classes/jogamp/newt/driver/macosx/ScreenDriver.java
+++ b/src/newt/classes/jogamp/newt/driver/macosx/ScreenDriver.java
@@ -77,7 +77,7 @@ public class ScreenDriver extends ScreenImpl {
     private class CrtProps {
         CrtProps() {
             count = getMonitorCount0();
-            pixelScaleArray = new int[count];
+            pixelScaleArray = new float[count];
             propsOrigArray = new int[count][];
             propsFixedArray = new int[count][];
 
@@ -85,8 +85,8 @@ public class ScreenDriver extends ScreenImpl {
             // Gather whole topology of monitors (NSScreens)
             //
             for(int crtIdx=0; crtIdx<count; crtIdx++) {
-                final float pixelScaleRaw = (float) OSXUtil.GetPixelScale(crtIdx);
-                pixelScaleArray[crtIdx] = FloatUtil.isZero(pixelScaleRaw, FloatUtil.EPSILON) ? 1 : (int)pixelScaleRaw;
+                final float pixelScaleRaw = (float)OSXUtil.GetPixelScaleByScreenIdx(crtIdx);
+                pixelScaleArray[crtIdx] = FloatUtil.isZero(pixelScaleRaw, FloatUtil.EPSILON) ? 1.0f : pixelScaleRaw;
                 propsOrigArray[crtIdx] = getMonitorProps0(crtIdx);
                 if ( null == propsOrigArray[crtIdx] ) {
                     throw new InternalError("Could not gather device props "+crtIdx+"/"+count);
@@ -105,7 +105,7 @@ public class ScreenDriver extends ScreenImpl {
                 final int[] thisMonitorProps = propsFixedArray[crtIdx];
                 final int x = thisMonitorProps[MonitorModeProps.IDX_MONITOR_DEVICE_VIEWPORT+0];
                 final int y = thisMonitorProps[MonitorModeProps.IDX_MONITOR_DEVICE_VIEWPORT+1];
-                final int thisPixelScale = pixelScaleArray[crtIdx];
+                final float thisPixelScale = pixelScaleArray[crtIdx];
                 thisMonitorProps[MonitorModeProps.IDX_MONITOR_DEVICE_VIEWPORT+2] *= thisPixelScale; // fix width
                 thisMonitorProps[MonitorModeProps.IDX_MONITOR_DEVICE_VIEWPORT+3] *= thisPixelScale; // fix height
                 if( 0 != x ) {
@@ -129,7 +129,7 @@ public class ScreenDriver extends ScreenImpl {
             }
         }
         final int count;
-        final int[] pixelScaleArray;
+        final float[] pixelScaleArray;
         final int[][] propsOrigArray;
         final int[][] propsFixedArray;
     }
@@ -167,12 +167,15 @@ public class ScreenDriver extends ScreenImpl {
                 throw new InternalError("Could not gather current mode of device "+crtIdx+"/"+crtProps.count+", but gathered "+modeIdx+" modes");
             }
             // merge monitor-props + supported modes
-            MonitorModeProps.streamInMonitorDevice(null, cache, this, supportedModes, currentMode, crtProps.propsFixedArray[crtIdx], 0);
+            final float pixelScale = crtProps.pixelScaleArray[crtIdx];
+            MonitorModeProps.streamInMonitorDevice(cache, this, currentMode,
+                                                   new float[] { pixelScale, pixelScale },
+                                                   supportedModes, crtProps.propsFixedArray[crtIdx], 0, null);
         }
     }
 
     @Override
-    protected boolean updateNativeMonitorDeviceViewportImpl(final MonitorDevice monitor, final Rectangle viewportPU, final Rectangle viewportWU) {
+    protected boolean updateNativeMonitorDeviceViewportImpl(final MonitorDevice monitor, final float[] pixelScale, final Rectangle viewportPU, final Rectangle viewportWU) {
         final CrtProps crtProps = new CrtProps();
         final int crtIdx = monitor.getId();
         if( 0 > crtIdx || crtIdx >= crtProps.count ) {
@@ -182,6 +185,9 @@ public class ScreenDriver extends ScreenImpl {
         int offset = MonitorModeProps.IDX_MONITOR_DEVICE_VIEWPORT;
         viewportPU.set(fixedMonitorProps[offset++], fixedMonitorProps[offset++], fixedMonitorProps[offset++], fixedMonitorProps[offset++]);
         viewportWU.set(fixedMonitorProps[offset++], fixedMonitorProps[offset++], fixedMonitorProps[offset++], fixedMonitorProps[offset++]);
+        final float _pixelScale = crtProps.pixelScaleArray[crtIdx];
+        pixelScale[0] = _pixelScale;
+        pixelScale[1] = _pixelScale;
         return true;
     }
 
diff --git a/src/newt/classes/jogamp/newt/driver/macosx/WindowDriver.java b/src/newt/classes/jogamp/newt/driver/macosx/WindowDriver.java
index c0f7d3859..a57bb5ac6 100644
--- a/src/newt/classes/jogamp/newt/driver/macosx/WindowDriver.java
+++ b/src/newt/classes/jogamp/newt/driver/macosx/WindowDriver.java
@@ -67,20 +67,26 @@ public class WindowDriver extends WindowImpl implements MutableSurface, DriverCl
     public WindowDriver() {
     }
 
-    private boolean updatePixelScale(final boolean sendEvent, final boolean defer, final float newPixelScaleRaw, final float nativePixelScaleRaw) {
-        final int[] newPixelScale = new int[2];
+    private boolean updatePixelScale(final boolean sendEvent, final boolean defer, final boolean deferOffThread,
+                                     final float newPixelScaleRaw, final float maxPixelScaleRaw) {
+        final float[] newPixelScale = new float[2];
         {
-            final int _newPixelScale = FloatUtil.isZero(newPixelScaleRaw, FloatUtil.EPSILON) ? ScalableSurface.IDENTITY_PIXELSCALE : (int) newPixelScaleRaw;
+            final float _newPixelScale = FloatUtil.isZero(newPixelScaleRaw, FloatUtil.EPSILON) ? ScalableSurface.IDENTITY_PIXELSCALE : newPixelScaleRaw;
             newPixelScale[0]= _newPixelScale;
             newPixelScale[1]= _newPixelScale;
-            final int _nativePixelScale = FloatUtil.isZero(nativePixelScaleRaw, FloatUtil.EPSILON) ? ScalableSurface.IDENTITY_PIXELSCALE : (int) nativePixelScaleRaw;
-            nativePixelScale[0]= _nativePixelScale;
-            nativePixelScale[1]= _nativePixelScale;
+            final float _maxPixelScale = FloatUtil.isZero(maxPixelScaleRaw, FloatUtil.EPSILON) ? ScalableSurface.IDENTITY_PIXELSCALE : maxPixelScaleRaw;
+            maxPixelScale[0]= _maxPixelScale;
+            maxPixelScale[1]= _maxPixelScale;
         }
+        // We keep minPixelScale at [1f, 1f]!
 
-        if( SurfaceScaleUtils.computePixelScale(hasPixelScale, hasPixelScale, reqPixelScale, newPixelScale, DEBUG_IMPLEMENTATION ? getClass().getName() : null) ) {
+        if( SurfaceScaleUtils.setNewPixelScale(hasPixelScale, hasPixelScale, newPixelScale, minPixelScale, maxPixelScale, DEBUG_IMPLEMENTATION ? getClass().getName() : null) ) {
             if( sendEvent ) {
-                super.sizeChanged(defer, getWidth(), getHeight(), true);
+                if( deferOffThread ) {
+                    superSizeChangedOffThread(defer, getWidth(), getHeight(), true);
+                } else {
+                    super.sizeChanged(defer, getWidth(), getHeight(), true);
+                }
             } else {
                 defineSize(getWidth(), getHeight());
             }
@@ -91,34 +97,34 @@ public class WindowDriver extends WindowImpl implements MutableSurface, DriverCl
     }
 
     private boolean updatePixelScaleByScreenIdx(final boolean sendEvent) {
-        final float nativePixelScaleRaw = (float) OSXUtil.GetPixelScale(getScreen().getIndex());
+        final float maxPixelScaleRaw = (float) OSXUtil.GetPixelScaleByScreenIdx(getScreen().getIndex());
         if( DEBUG_IMPLEMENTATION ) {
-            System.err.println("WindowDriver.updatePixelScale.1: "+hasPixelScale[0]+", "+nativePixelScaleRaw+" (native)");
+            System.err.println("WindowDriver.updatePixelScale.1: "+hasPixelScale[0]+", "+maxPixelScaleRaw+" (max)");
         }
-        return updatePixelScale(sendEvent, true /* defer */, nativePixelScaleRaw, nativePixelScaleRaw);
+        return updatePixelScale(sendEvent, true /* defer */, false /*offthread */, maxPixelScaleRaw, maxPixelScaleRaw);
     }
 
     private boolean updatePixelScaleByWindowHandle(final boolean sendEvent) {
         final long handle = getWindowHandle();
         if( 0 != handle ) {
-            final float nativePixelScaleRaw = (float)OSXUtil.GetPixelScale(handle);
+            final float maxPixelScaleRaw = (float)OSXUtil.GetPixelScale(handle);
             if( DEBUG_IMPLEMENTATION ) {
-                System.err.println("WindowDriver.updatePixelScale.2: "+hasPixelScale[0]+", "+nativePixelScaleRaw+" (native)");
+                System.err.println("WindowDriver.updatePixelScale.2: "+hasPixelScale[0]+", "+maxPixelScaleRaw+" (max)");
             }
-            return updatePixelScale(sendEvent, true /* defer */, nativePixelScaleRaw, nativePixelScaleRaw);
+            return updatePixelScale(sendEvent, true /* defer */, false /*offthread */, maxPixelScaleRaw, maxPixelScaleRaw);
         } else {
             return false;
         }
     }
 
     /** Called from native code */
-    protected void updatePixelScale(final boolean defer, final float newPixelScaleRaw, final float nativePixelScaleRaw) {
+    protected void updatePixelScale(final boolean defer, final float newPixelScaleRaw, final float maxPixelScaleRaw) {
         final long handle = getWindowHandle();
         if( DEBUG_IMPLEMENTATION ) {
-            System.err.println("WindowDriver.updatePixelScale.3: "+hasPixelScale[0]+" (has) -> "+newPixelScaleRaw+" (raw), "+nativePixelScaleRaw+" (native), drop "+(0==handle));
+            System.err.println("WindowDriver.updatePixelScale.3: "+hasPixelScale[0]+" (has) -> "+newPixelScaleRaw+" (new), "+maxPixelScaleRaw+" (max), drop "+(0==handle));
         }
         if( 0 != handle ) {
-            updatePixelScale(true /* sendEvent*/, defer, newPixelScaleRaw, nativePixelScaleRaw);
+            updatePixelScale(true /* sendEvent*/, defer, true /*offthread */, newPixelScaleRaw, maxPixelScaleRaw);
         }
     }
 
@@ -139,44 +145,47 @@ public class WindowDriver extends WindowImpl implements MutableSurface, DriverCl
     }
 
     @Override
-    public final void setSurfaceScale(final int[] pixelScale) {
-        SurfaceScaleUtils.validateReqPixelScale(reqPixelScale, pixelScale, DEBUG_IMPLEMENTATION ? getClass().getName() : null);
+    public final boolean setSurfaceScale(final float[] pixelScale) {
+        super.setSurfaceScale(pixelScale);
 
-        final int[] resPixelScale;
+        boolean changed = false;
         if( isNativeValid() ) {
             if( isOffscreenInstance ) {
                 final NativeWindow pWin = getParent();
                 if( pWin instanceof ScalableSurface ) {
                     final ScalableSurface sSurf = (ScalableSurface)pWin;
                     sSurf.setSurfaceScale(reqPixelScale);
-                    final int[] pPixelScale = sSurf.getCurrentSurfaceScale(new int[2]);
-                    sSurf.getNativeSurfaceScale(nativePixelScale);
-                    updatePixelScale(true /* sendEvent */, true /* defer */, pPixelScale[0], nativePixelScale[0]); // HiDPI: uniformPixelScale
+                    sSurf.getMaximumSurfaceScale(maxPixelScale);
+                    sSurf.getMinimumSurfaceScale(minPixelScale);
+                    final float[] pPixelScale = sSurf.getCurrentSurfaceScale(new float[2]);
+                    changed = updatePixelScale(true /* sendEvent */, true /* defer */, true /*offthread */, pPixelScale[0], maxPixelScale[0]); // HiDPI: uniformPixelScale
                 } else {
                     // just notify updated pixelScale if offscreen
-                    SurfaceScaleUtils.replaceAutoMaxWithPlatformMax(reqPixelScale);
-                    updatePixelScale(true /* sendEvent */, true /* defer */, reqPixelScale[0], nativePixelScale[0]); // HiDPI: uniformPixelScale
+                    changed = updatePixelScale(true /* sendEvent */, true /* defer */, true /*offthread */, reqPixelScale[0], maxPixelScale[0]); // HiDPI: uniformPixelScale
                 }
             } else {
-                // set pixelScale in native code, will issue an update PixelScale
-                OSXUtil.RunOnMainThread(true, false, new Runnable() {
-                    @Override
-                    public void run() {
-                        setPixelScale0(getWindowHandle(), surfaceHandle, reqPixelScale[0]); // HiDPI: uniformPixelScale
-                    }
-                } );
+                // set pixelScale in native code, will issue an update updatePixelScale(..)
+                // hence we pre-query whether pixel-scale will change, without affecting current state 'hasPixelScale'!
+                final float[] _hasPixelScale = new float[2];
+                System.arraycopy(hasPixelScale, 0, _hasPixelScale, 0, 2);
+                if( SurfaceScaleUtils.setNewPixelScale(_hasPixelScale, _hasPixelScale, reqPixelScale, minPixelScale, maxPixelScale, DEBUG_IMPLEMENTATION ? getClass().getName() : null) ) {
+                    OSXUtil.RunOnMainThread(true, false, new Runnable() {
+                        @Override
+                        public void run() {
+                            setPixelScale0(getWindowHandle(), surfaceHandle, _hasPixelScale[0]); // HiDPI: uniformPixelScale
+                        }
+                    } );
+                    changed = true;
+                }
             }
-            resPixelScale = hasPixelScale;
-        } else {
-            hasPixelScale[0] = ScalableSurface.IDENTITY_PIXELSCALE;
-            hasPixelScale[1] = ScalableSurface.IDENTITY_PIXELSCALE;
-            resPixelScale = reqPixelScale;
         }
         if( DEBUG_IMPLEMENTATION ) {
-            System.err.println("WindowDriver.setPixelScale: "+pixelScale[0]+"x"+pixelScale[1]+" (req) -> "+
-                                reqPixelScale[0]+"x"+reqPixelScale[1]+" (validated) -> "+
-                                resPixelScale[0]+"x"+resPixelScale[1]+" (result) - realized "+isNativeValid());
+            System.err.println("WindowDriver.setPixelScale: min["+minPixelScale[0]+", "+minPixelScale[1]+"], max["+
+                                maxPixelScale[0]+", "+maxPixelScale[1]+"], req["+
+                                reqPixelScale[0]+", "+reqPixelScale[1]+"] -> result["+
+                                hasPixelScale[0]+", "+hasPixelScale[1]+"] - changed "+changed+", realized "+isNativeValid());
         }
+        return changed;
     }
 
     @Override
@@ -360,13 +369,23 @@ public class WindowDriver extends WindowImpl implements MutableSurface, DriverCl
                     System.err.println("MacWindow: sizeChanged() parent["+useParent+" "+x+"/"+y+"] "+getX()+"/"+getY()+" "+newWidth+"x"+newHeight+" ->  "+p0S+" screen-client-pos");
                 }
                 OSXUtil.RunOnMainThread(false, false, new Runnable() {
-                        @Override
-                        public void run() {
-                            setWindowClientTopLeftPoint0(getWindowHandle(), p0S.getX(), p0S.getY(), isVisible());
-                        } } );
+                    @Override
+                    public void run() {
+                        setWindowClientTopLeftPoint0(getWindowHandle(), p0S.getX(), p0S.getY(), isVisible());
+                    } } );
             }
         }
-        super.sizeChanged(defer, newWidth, newHeight, force);
+        superSizeChangedOffThread(defer, newWidth, newHeight, force);
+    }
+    private void superSizeChangedOffThread(final boolean defer, final int newWidth, final int newHeight, final boolean force) {
+        if( defer ) {
+            new Thread() {
+                public void run() {
+                    WindowDriver.super.sizeChanged(false /* defer */, newWidth, newHeight, force);
+                } }.start();
+        } else {
+            WindowDriver.super.sizeChanged(false /* defer */, newWidth, newHeight, force);
+        }
     }
 
     @Override
@@ -556,14 +575,18 @@ public class WindowDriver extends WindowImpl implements MutableSurface, DriverCl
     @Override
     protected void warpPointerImpl(final int x, final int y) {
         if( !isOffscreenInstance ) {
-            warpPointer0(getWindowHandle(), x / getPixelScaleX(), y / getPixelScaleY());
+            warpPointer0(getWindowHandle(),
+                         SurfaceScaleUtils.scaleInv(x, getPixelScaleX()),
+                         SurfaceScaleUtils.scaleInv(y, getPixelScaleY()));
         } // else may need offscreen solution ? FIXME
     }
 
     @Override
     protected final void doMouseEvent(final boolean enqueue, final boolean wait, final short eventType, final int modifiers,
                                       final int x, final int y, final short button, final float[] rotationXYZ, final float rotationScale) {
-        super.doMouseEvent(enqueue, wait, eventType, modifiers, x * getPixelScaleX(), y * getPixelScaleY(), button, rotationXYZ, rotationScale);
+        super.doMouseEvent(enqueue, wait, eventType, modifiers,
+                           SurfaceScaleUtils.scale(x, getPixelScaleX()),
+                           SurfaceScaleUtils.scale(y, getPixelScaleY()), button, rotationXYZ, rotationScale);
     }
 
     @Override
diff --git a/src/newt/classes/jogamp/newt/driver/windows/ScreenDriver.java b/src/newt/classes/jogamp/newt/driver/windows/ScreenDriver.java
index 38acd03ae..79ba623f8 100644
--- a/src/newt/classes/jogamp/newt/driver/windows/ScreenDriver.java
+++ b/src/newt/classes/jogamp/newt/driver/windows/ScreenDriver.java
@@ -106,7 +106,7 @@ public class ScreenDriver extends ScreenImpl {
                 if ( null != currentMode ) { // enabled
                     final int[] monitorProps = getMonitorDevice0(adapterName, crtIdx);
                     // merge monitor-props + supported modes
-                    MonitorModeProps.streamInMonitorDevice(null, cache, this, supportedModes, currentMode, monitorProps, 0);
+                    MonitorModeProps.streamInMonitorDevice(cache, this, currentMode, null, supportedModes, monitorProps, 0, null);
 
                     // next monitor, 1st mode
                     supportedModes= new ArrayHashSet<MonitorMode>();
@@ -118,7 +118,7 @@ public class ScreenDriver extends ScreenImpl {
     }
 
     @Override
-    protected boolean updateNativeMonitorDeviceViewportImpl(final MonitorDevice monitor, final Rectangle viewportPU, final Rectangle viewportWU) {
+    protected boolean updateNativeMonitorDeviceViewportImpl(final MonitorDevice monitor, final float[] pixelScale, final Rectangle viewportPU, final Rectangle viewportWU) {
         final String adapterName = getAdapterName(monitor.getId());
         if( null != adapterName ) {
             final String activeMonitorName = getActiveMonitorName(adapterName, 0);
diff --git a/src/newt/classes/jogamp/newt/driver/x11/ScreenDriver.java b/src/newt/classes/jogamp/newt/driver/x11/ScreenDriver.java
index f7361740e..1ec91dce2 100644
--- a/src/newt/classes/jogamp/newt/driver/x11/ScreenDriver.java
+++ b/src/newt/classes/jogamp/newt/driver/x11/ScreenDriver.java
@@ -152,7 +152,7 @@ public class ScreenDriver extends ScreenImpl {
                             if( null != monitorProps &&
                                 MonitorModeProps.MIN_MONITOR_DEVICE_PROPERTIES <= monitorProps[0] && // Enabled ? I.e. contains active modes ?
                                 MonitorModeProps.MIN_MONITOR_DEVICE_PROPERTIES <= monitorProps.length ) {
-                                MonitorModeProps.streamInMonitorDevice(null, cache, this, monitorProps, 0);
+                                MonitorModeProps.streamInMonitorDevice(cache, this, null, monitorProps, 0, null);
                             }
                         }
                     }
@@ -166,7 +166,7 @@ public class ScreenDriver extends ScreenImpl {
     }
 
     @Override
-    protected boolean updateNativeMonitorDeviceViewportImpl(final MonitorDevice monitor, final Rectangle viewportPU, final Rectangle viewportWU) {
+    protected boolean updateNativeMonitorDeviceViewportImpl(final MonitorDevice monitor, final float[] pixelScale, final Rectangle viewportPU, final Rectangle viewportWU) {
         final AbstractGraphicsDevice device = getDisplay().getGraphicsDevice();
         device.lock();
         try {
diff --git a/src/newt/native/MacWindow.m b/src/newt/native/MacWindow.m
index 2bd11da3c..1dbe2b7bd 100644
--- a/src/newt/native/MacWindow.m
+++ b/src/newt/native/MacWindow.m
@@ -420,7 +420,7 @@ NS_ENDHANDLER
 
 
 CGDirectDisplayID NewtScreen_getCGDirectDisplayIDByNSScreen(NSScreen *screen) {
-    // Mind: typedef uint32_t CGDirectDisplayID; - however, we assume it's 64bit on 64bit ?!
+    // Mind: typedef uint32_t CGDirectDisplayID;
     NSDictionary * dict = [screen deviceDescription];
     NSNumber * val = (NSNumber *) [dict objectForKey: @"NSScreenNumber"];
     // [NSNumber integerValue] returns NSInteger which is 32 or 64 bit native size
diff --git a/src/newt/native/NewtMacWindow.m b/src/newt/native/NewtMacWindow.m
index caf9e54e0..7b3df391d 100644
--- a/src/newt/native/NewtMacWindow.m
+++ b/src/newt/native/NewtMacWindow.m
@@ -784,11 +784,21 @@ static jmethodID windowRepaintID = NULL;
     [super viewDidChangeBackingProperties];
 
     // HiDPI scaling
-    BOOL useHiDPI = [self wantsBestResolutionOpenGLSurface];
-    CGFloat pixelScaleNative = [[self window] backingScaleFactor];
-    CGFloat pixelScaleUse = useHiDPI ? pixelScaleNative : 1.0;
-    DBG_PRINT("viewDidChangeBackingProperties: PixelScale: HiDPI %d, native %f -> use %f\n", useHiDPI, (float)pixelScaleNative, (float)pixelScaleUse);
-    [[self layer] setContentsScale: pixelScaleUse];
+    BOOL useHiDPI = false;
+    CGFloat maxPixelScale = 1.0;
+    CGFloat winPixelScale = 1.0;
+    NSWindow* window = [self window];
+    NSScreen* screen = [window screen];
+NS_DURING
+    maxPixelScale = [screen backingScaleFactor];
+    useHiDPI = [self wantsBestResolutionOpenGLSurface];
+    if( useHiDPI ) {
+        winPixelScale = [window backingScaleFactor];
+    }
+NS_HANDLER
+NS_ENDHANDLER
+    DBG_PRINT("viewDidChangeBackingProperties: PixelScale: HiDPI %d, max %f, window %f\n", useHiDPI, (float)maxPixelScale, (float)winPixelScale);
+    [[self layer] setContentsScale: winPixelScale];
 
     if (javaWindowObject == NULL) {
         DBG_PRINT("viewDidChangeBackingProperties: null javaWindowObject\n");
@@ -801,7 +811,7 @@ static jmethodID windowRepaintID = NULL;
         return;
     }
 
-    (*env)->CallVoidMethod(env, javaWindowObject, updatePixelScaleID, JNI_TRUE, (jfloat)pixelScaleUse, (jfloat)pixelScaleNative); // defer 
+    (*env)->CallVoidMethod(env, javaWindowObject, updatePixelScaleID, JNI_TRUE, (jfloat)winPixelScale, (jfloat)maxPixelScale); // defer 
 
     // detaching thread not required - daemon
     // NewtCommon_ReleaseJNIEnv(shallBeDetached);