Bug 741 HiDPI: Add ScalableSurface.getNativeSurfaceScale(..) to compute surface DPI ; Add NEWT Window.getPixelsPerMM(..) to query surface DPI

With HiDPI and surface scale, we need knowledge of the native surface's pixel-scale
matching the monitor's pixel-per-millimeter value.

Preserving the queried native pixel-scale and exposing it via
ScalableSurface.getNativeSurfaceScale(..) to compute surface DPI.

Add NEWT Window.getPixelsPerMM(..) to query surface DPI.

Surface DPI is demonstrated in GraphUI's GPUUISceneGLListener0A .. and TestRulerNEWT01, etc ..

5 files changed, 60 insertions, 27 deletions

diff --git a/src/nativewindow/classes/com/jogamp/nativewindow/awt/JAWTWindow.java b/src/nativewindow/classes/com/jogamp/nativewindow/awt/JAWTWindow.java
index 1cc8fdb01..62710830f 100644
--- a/src/nativewindow/classes/com/jogamp/nativewindow/awt/JAWTWindow.java
+++ b/src/nativewindow/classes/com/jogamp/nativewindow/awt/JAWTWindow.java
@@ -101,7 +101,8 @@ public abstract class JAWTWindow implements NativeWindow, OffscreenLayerSurface,
   protected Insets insets;
   private volatile long offscreenSurfaceLayer;
 
-  private volatile int[] hasPixelScale = new int[] { ScalableSurface.IDENTITY_PIXELSCALE, ScalableSurface.IDENTITY_PIXELSCALE };
+  private final int[] nativePixelScale = new int[] { ScalableSurface.IDENTITY_PIXELSCALE, ScalableSurface.IDENTITY_PIXELSCALE };
+  private final int[] hasPixelScale = new int[] { ScalableSurface.IDENTITY_PIXELSCALE, ScalableSurface.IDENTITY_PIXELSCALE };
   protected final int[] reqPixelScale = new int[] { ScalableSurface.AUTOMAX_PIXELSCALE, ScalableSurface.AUTOMAX_PIXELSCALE };
 
   private long drawable_old;
@@ -266,6 +267,8 @@ public abstract class JAWTWindow implements NativeWindow, OffscreenLayerSurface,
     insets = new Insets();
     hasPixelScale[0] = ScalableSurface.IDENTITY_PIXELSCALE;
     hasPixelScale[1] = ScalableSurface.IDENTITY_PIXELSCALE;
+    nativePixelScale[0] = ScalableSurface.IDENTITY_PIXELSCALE;
+    nativePixelScale[1] = ScalableSurface.IDENTITY_PIXELSCALE;
   }
   protected abstract void invalidateNative();
 
@@ -293,6 +296,12 @@ public abstract class JAWTWindow implements NativeWindow, OffscreenLayerSurface,
       return result;
   }
 
+  @Override
+  public final int[] getNativeSurfaceScale(final int[] result) {
+      System.arraycopy(nativePixelScale, 0, result, 0, 2);
+      return result;
+  }
+
   /**
    * Updates bounds and pixelScale
    * @return true if bounds or pixelScale has changed, otherwise false
@@ -312,6 +321,11 @@ public abstract class JAWTWindow implements NativeWindow, OffscreenLayerSurface,
             insets.set(contInsets.left, contInsets.right, contInsets.top, contInsets.bottom);
         }
     }
+    {
+        final int ps = JAWTUtil.getPixelScale(config.getAWTGraphicsConfiguration());
+        nativePixelScale[0] = ps;
+        nativePixelScale[1] = ps;
+    }
 
     return updatePixelScale() || changedBounds;
   }
@@ -321,12 +335,7 @@ public abstract class JAWTWindow implements NativeWindow, OffscreenLayerSurface,
    * @return true if pixelScale has changed, otherwise false
    */
   protected final boolean updatePixelScale() {
-    final int[] pixelScaleInt;
-    {
-        final int ps = JAWTUtil.getPixelScale(config.getAWTGraphicsConfiguration());
-        pixelScaleInt = new int[] { ps, ps };
-    }
-    return SurfaceScaleUtils.computePixelScale(hasPixelScale, hasPixelScale, reqPixelScale, pixelScaleInt, DEBUG ? getClass().getSimpleName() : null);
+    return SurfaceScaleUtils.computePixelScale(hasPixelScale, hasPixelScale, reqPixelScale, nativePixelScale, DEBUG ? getClass().getSimpleName() : null);
   }
 
   /** @return the JAWT_DrawingSurfaceInfo's (JAWT_Rectangle) bounds, updated with lock */
diff --git a/src/nativewindow/classes/javax/media/nativewindow/ScalableSurface.java b/src/nativewindow/classes/javax/media/nativewindow/ScalableSurface.java
index de6ba51d7..ffd5c224c 100644
--- a/src/nativewindow/classes/javax/media/nativewindow/ScalableSurface.java
+++ b/src/nativewindow/classes/javax/media/nativewindow/ScalableSurface.java
@@ -65,7 +65,7 @@ public interface ScalableSurface {
    * Returns the requested pixel scale of the associated {@link NativeSurface}.
    *
    * @param result int[2] storage for the result
-   * @return the passed storage containing the requested pixelSize for chaining
+   * @return the passed storage containing the requested pixelScale for chaining
    */
   int[] getRequestedSurfaceScale(final int[] result);
 
@@ -73,8 +73,25 @@ public interface ScalableSurface {
    * Returns the current pixel scale of the associated {@link NativeSurface}.
    *
    * @param result int[2] storage for the result
-   * @return the passed storage containing the current pixelSize for chaining
+   * @return the passed storage containing the current pixelScale for chaining
    */
   public int[] getCurrentSurfaceScale(final int[] result);
+
+  /**
+   * Returns the native pixel scale of the associated {@link NativeSurface}
+   * reflecting it's currently bound <i>monitor surface resolution in pixels</i>.
+   * <p>
+   * The native pixel scale maybe used to determine the proper <i>dpi</i>
+   * value of this {@link NativeSurface}:
+   * <pre>
+   *    surfacePpMM = monitorPpMM * currentSurfaceScale / nativeSurfaceScale,
+   *    with PpMM == pixel per millimeter
+   * </pre>
+   * </p>
+   *
+   * @param result int[2] storage for the result
+   * @return the passed storage containing the native pixelScale for chaining
+   */
+  public int[] getNativeSurfaceScale(final int[] result);
 }
 
diff --git a/src/nativewindow/classes/javax/media/nativewindow/util/Dimension.java b/src/nativewindow/classes/javax/media/nativewindow/util/Dimension.java
index 24ccc836a..5c9dc279d 100644
--- a/src/nativewindow/classes/javax/media/nativewindow/util/Dimension.java
+++ b/src/nativewindow/classes/javax/media/nativewindow/util/Dimension.java
@@ -37,7 +37,11 @@ public class Dimension implements Cloneable, DimensionImmutable {
         this(0, 0);
     }
 
-    public Dimension(int width, int height) {
+    public Dimension(final int[] size) {
+        this(size[0], size[1]);
+    }
+
+    public Dimension(final int width, final int height) {
         if(width<0 || height<0) {
             throw new IllegalArgumentException("width and height must be within: ["+0+".."+Integer.MAX_VALUE+"]");
         }
diff --git a/src/nativewindow/classes/jogamp/nativewindow/SurfaceScaleUtils.java b/src/nativewindow/classes/jogamp/nativewindow/SurfaceScaleUtils.java
index 22e67ecff..3aea58852 100644
--- a/src/nativewindow/classes/jogamp/nativewindow/SurfaceScaleUtils.java
+++ b/src/nativewindow/classes/jogamp/nativewindow/SurfaceScaleUtils.java
@@ -58,37 +58,34 @@ public class SurfaceScaleUtils {
      * @param result int[2] storage for result, maybe same as <code>prePixelScale</code> for in-place
      * @param prePixelScale previous pixelScale
      * @param reqPixelScale requested pixelScale, validated via {@link #validateReqPixelScale(int[], int, String)}.
-     * @param surfPixelScaleRaw raw surface pixelScale
+     * @param newPixelScaleRaw new raw surface pixelScale
      * @param DEBUG_PREFIX if set, dumps debug info on stderr using this prefix
      * @return true if pixelScale has changed, otherwise false
      */
-    public static boolean computePixelScale(int[] result, final int[] prePixelScale, final int[] reqPixelScale, final int[] surfPixelScaleRaw, final String DEBUG_PREFIX) {
-        final int surfPixelScaleSafeX = 0 < surfPixelScaleRaw[0] ? surfPixelScaleRaw[0] : ScalableSurface.IDENTITY_PIXELSCALE;
-        final int surfPixelScaleSafeY = 0 < surfPixelScaleRaw[1] ? surfPixelScaleRaw[1] : ScalableSurface.IDENTITY_PIXELSCALE;
+    public static boolean computePixelScale(int[] result, final int[] prePixelScale, final int[] reqPixelScale, final int[] newPixelScaleRaw, final String DEBUG_PREFIX) {
+        final int newPixelScaleSafeX = 0 < newPixelScaleRaw[0] ? newPixelScaleRaw[0] : ScalableSurface.IDENTITY_PIXELSCALE;
+        final int newPixelScaleSafeY = 0 < newPixelScaleRaw[1] ? newPixelScaleRaw[1] : ScalableSurface.IDENTITY_PIXELSCALE;
         final boolean useHiDPI = ScalableSurface.IDENTITY_PIXELSCALE != reqPixelScale[0] || ScalableSurface.IDENTITY_PIXELSCALE != reqPixelScale[1];
         final int prePixelScaleX = prePixelScale[0];
         final int prePixelScaleY = prePixelScale[1];
 
         if( useHiDPI ) {
-            result[0] = surfPixelScaleSafeX;
-            result[1] = surfPixelScaleSafeY;
+            result[0] = newPixelScaleSafeX;
+            result[1] = newPixelScaleSafeY;
         } else {
             result[0] = ScalableSurface.IDENTITY_PIXELSCALE;
             result[1] = ScalableSurface.IDENTITY_PIXELSCALE;
         }
 
-        if( result[0] != prePixelScaleX || result[1] != prePixelScaleY ) {
-            if( null != DEBUG_PREFIX ) {
-                System.err.println(DEBUG_PREFIX+".computePixelScale: useHiDPI "+useHiDPI+", ["+prePixelScaleX+"x"+prePixelScaleY+" (pre), "+
-                        reqPixelScale[0]+"x"+reqPixelScale[1]+" (req)] -> "+
-                        surfPixelScaleRaw[0]+"x"+surfPixelScaleRaw[1]+" (raw) -> "+
-                        surfPixelScaleSafeX+"x"+surfPixelScaleSafeY+" (safe) -> "+
-                        result[0]+"x"+result[1]+" (use)");
-            }
-            return true;
-        } else {
-            return false;
+        final boolean changed = result[0] != prePixelScaleX || result[1] != prePixelScaleY;
+        if( null != DEBUG_PREFIX ) {
+            System.err.println(DEBUG_PREFIX+".computePixelScale: useHiDPI "+useHiDPI+", ["+prePixelScaleX+"x"+prePixelScaleY+" (pre), "+
+                    reqPixelScale[0]+"x"+reqPixelScale[1]+" (req)] -> "+
+                    newPixelScaleRaw[0]+"x"+newPixelScaleRaw[1]+" (raw) -> "+
+                    newPixelScaleSafeX+"x"+newPixelScaleSafeY+" (safe) -> "+
+                    result[0]+"x"+result[1]+" (use), changed "+changed);
         }
+        return changed;
     }
 
     /**
diff --git a/src/nativewindow/classes/jogamp/nativewindow/WrappedSurface.java b/src/nativewindow/classes/jogamp/nativewindow/WrappedSurface.java
index 8f9379130..752057a49 100644
--- a/src/nativewindow/classes/jogamp/nativewindow/WrappedSurface.java
+++ b/src/nativewindow/classes/jogamp/nativewindow/WrappedSurface.java
@@ -164,4 +164,10 @@ public class WrappedSurface extends ProxySurfaceImpl implements ScalableSurface
       return result;
   }
 
+  @Override
+  public final int[] getNativeSurfaceScale(final int[] result) {
+      System.arraycopy(hasPixelScale, 0, result, 0, 2);
+      return result;
+  }
+
 }
\ No newline at end of file