Bug 740569 - Make the display port strategy preffable. r=Cwiiis

mobile/android/app/mobile.js

@@ -361,6 +361,10 @@ pref("places.frecency.unvisitedTypedBonus", 200);
 
 // disable color management
 pref("gfx.color_management.mode", 0);
+#ifdef ANDROID
+// 0=fixed margin, 1=velocity bias, 2=dynamic resolution, 3=no margins
+pref("gfx.displayport.strategy", 0);
+#endif
 
 // don't allow JS to move and resize existing windows
 pref("dom.disable_window_move_resize", true);

mobile/android/base/gfx/DisplayPortCalculator.java

@@ -7,6 +7,7 @@ package org.mozilla.gecko.gfx;
 
 import android.graphics.PointF;
 import android.graphics.RectF;
+import android.util.Log;
 import org.mozilla.gecko.FloatUtils;
 import org.mozilla.gecko.GeckoAppShell;
 
@@ -27,6 +28,30 @@ final class DisplayPortCalculator {
         return sStrategy.aboutToCheckerboard(metrics, (velocity == null ? ZERO_VELOCITY : velocity), displayPort);
     }
 
+    /**
+     * Set the active strategy to use.
+     * See the gfx.displayport.strategy pref in mobile/android/app/mobile.js to see the
+     * mapping between ints and strategies.
+     */
+    static void setStrategy(int strategy) {
+        switch (strategy) {
+            case 0:
+            default:
+                sStrategy = new FixedMarginStrategy();
+                break;
+            case 1:
+                sStrategy = new VelocityBiasStrategy();
+                break;
+            case 2:
+                sStrategy = new DynamicResolutionStrategy();
+                break;
+            case 3:
+                sStrategy = new NoMarginStrategy();
+                break;
+        }
+        Log.i(LOGTAG, "Set strategy " + sStrategy.getClass().getName());
+    }
+
     private interface DisplayPortStrategy {
         /** Calculates a displayport given a viewport and panning velocity. */
         public DisplayPortMetrics calculate(ImmutableViewportMetrics metrics, PointF velocity);

mobile/android/base/gfx/GeckoLayerClient.java

@@ -43,6 +43,7 @@ import org.mozilla.gecko.GeckoApp;
 import org.mozilla.gecko.GeckoAppShell;
 import org.mozilla.gecko.GeckoEvent;
 import org.mozilla.gecko.GeckoEventResponder;
+import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 import android.content.Context;
@@ -59,6 +60,7 @@ import android.view.View;
 public class GeckoLayerClient implements GeckoEventResponder,
                                          FlexibleGLSurfaceView.Listener {
     private static final String LOGTAG = "GeckoLayerClient";
+    private static final String PREF_DISPLAYPORT_STRATEGY = "gfx.displayport.strategy";
 
     private LayerController mLayerController;
     private LayerRenderer mLayerRenderer;
@@ -110,12 +112,14 @@ public class GeckoLayerClient implements GeckoEventResponder,
         GeckoAppShell.registerGeckoEventListener("Viewport:PageSize", this);
         GeckoAppShell.registerGeckoEventListener("Viewport:CalculateDisplayPort", this);
         GeckoAppShell.registerGeckoEventListener("Checkerboard:Toggle", this);
+        GeckoAppShell.registerGeckoEventListener("Preferences:Data", this);
 
         view.setListener(this);
         view.setLayerRenderer(mLayerRenderer);
         layerController.setRoot(mRootLayer);
 
         sendResizeEventIfNecessary(true);
+        GeckoAppShell.sendEventToGecko(GeckoEvent.createBroadcastEvent("Preferences:Get", "[ \"" + PREF_DISPLAYPORT_STRATEGY + "\" ]"));
     }
 
     DisplayPortMetrics getDisplayPort() {
@@ -234,16 +238,21 @@ public class GeckoLayerClient implements GeckoEventResponder,
                 ImmutableViewportMetrics newMetrics = new ImmutableViewportMetrics(new ViewportMetrics(message));
                 mReturnDisplayPort = DisplayPortCalculator.calculate(newMetrics, null);
             } else if ("Checkerboard:Toggle".equals(event)) {
-                try {
+                boolean showChecks = message.getBoolean("value");
-                    boolean showChecks = message.getBoolean("value");
+                mLayerController.setCheckerboardShowChecks(showChecks);
-                    mLayerController.setCheckerboardShowChecks(showChecks);
+                Log.i(LOGTAG, "Showing checks: " + showChecks);
-                    Log.i(LOGTAG, "Showing checks: " + showChecks);
+            } else if ("Preferences:Data".equals(event)) {
-                } catch(JSONException ex) {
+                JSONArray jsonPrefs = message.getJSONArray("preferences");
-                    Log.e(LOGTAG, "Error decoding JSON", ex);
+                for (int i = jsonPrefs.length() - 1; i >= 0; i--) {
+                    JSONObject pref = jsonPrefs.getJSONObject(i);
+                    if (pref.getString("name").equals(PREF_DISPLAYPORT_STRATEGY)) {
+                        DisplayPortCalculator.setStrategy(pref.getInt("value"));
+                        GeckoAppShell.unregisterGeckoEventListener("Preferences:Data", this);
+                    }
                 }
             }
         } catch (JSONException e) {
-            Log.e(LOGTAG, "Unable to create viewport metrics in " + event + " handler", e);
+            Log.e(LOGTAG, "Error decoding JSON in " + event + " handler", e);
         }
     }