Merge "Set reading level scale to display density instead of a fixed minimum."

core/java/android/webkit/WebView.java

@@ -2345,6 +2345,14 @@ public class WebView extends AbsoluteLayout
         return mZoomManager.getScale();
     }
 
+    /**
+     * Return the reading level scale of the WebView
+     * @return The reading level scale.
+     */
+    /*package*/ float getReadingLevelScale() {
+        return mZoomManager.getReadingLevelScale();
+    }
+
     /**
      * Set the initial scale for the WebView. 0 means default. If
      * {@link WebSettings#getUseWideViewPort()} is true, it zooms out all the

core/java/android/webkit/WebViewCore.java

@@ -2460,7 +2460,7 @@ public final class WebViewCore {
                     if (mSettings.isNarrowColumnLayout()) {
                         // In case of automatic text reflow in fixed view port mode.
                         mInitialViewState.mTextWrapScale =
-                                ZoomManager.computeReadingLevelScale(data.mScale);
+                                mWebView.getReadingLevelScale();
                     }
                 } else {
                     // Scale is given such as when page is restored, use it.

core/java/android/webkit/ZoomManager.java

@@ -57,13 +57,6 @@ class ZoomManager {
     private ZoomControlEmbedded mEmbeddedZoomControl;
     private ZoomControlExternal mExternalZoomControl;
 
-    /*
-     * For large screen devices, the defaultScale usually set to 1.0 and
-     * equal to the overview scale, to differentiate the zoom level for double tapping,
-     * a default reading level scale is used.
-     */
-    private static final float DEFAULT_READING_LEVEL_SCALE = 1.5f;
-
     /*
      * The scale factors that determine the upper and lower bounds for the
      * default zoom scale.
@@ -151,6 +144,19 @@ class ZoomManager {
     private float mDefaultScale;
     private float mInvDefaultScale;
 
+    /*
+     * The scale factor that is used to determine the zoom level for reading text.
+     * The value is initially set to equal the display density.
+     * TODO: Support changing this in WebSettings
+     */
+    private float mReadingLevelScale;
+
+    /*
+     * The scale factor that is used as the minimum increment when going from
+     * overview to reading level on a double tap.
+     */
+    private static float MIN_DOUBLE_TAP_SCALE_INCREMENT = 0.5f;
+
     // the current computed zoom scale and its inverse.
     private float mActualScale;
     private float mInvActualScale;
@@ -230,6 +236,7 @@ class ZoomManager {
         setDefaultZoomScale(density);
         mActualScale = density;
         mInvActualScale = 1 / density;
+        mReadingLevelScale = density;
         mTextWrapScale = density;
     }
 
@@ -304,13 +311,7 @@ class ZoomManager {
     }
 
     public final float getReadingLevelScale() {
-        return computeScaleWithLimits(computeReadingLevelScale(getZoomOverviewScale()));
+        return mReadingLevelScale;
-    }
-
-    /* package */ final static float computeReadingLevelScale(float scale) {
-        // The reading scale is at least 0.5f apart from the input scale.
-        final float MIN_SCALE_DIFF = 0.5f;
-        return Math.max(scale + MIN_SCALE_DIFF, DEFAULT_READING_LEVEL_SCALE);
     }
 
     public final float getInvDefaultScale() {
@@ -652,7 +653,7 @@ class ZoomManager {
         } else if (!mInZoomOverview && willScaleTriggerZoom(getZoomOverviewScale())) {
             zoomToOverview();
         } else {
-            zoomToReadingLevel();
+            zoomToReadingLevelOrMore();
         }
     }
 
@@ -683,8 +684,10 @@ class ZoomManager {
             !mWebView.getSettings().getUseFixedViewport());
     }
 
-    private void zoomToReadingLevel() {
+    private void zoomToReadingLevelOrMore() {
-        final float readingScale = getReadingLevelScale();
+        final float zoomScale = Math.max(getReadingLevelScale(),
+                mActualScale + MIN_DOUBLE_TAP_SCALE_INCREMENT);
+
         int left = mWebView.nativeGetBlockLeftEdge(mAnchorX, mAnchorY, mActualScale);
         if (left != WebView.NO_LEFTEDGE) {
             // add a 5pt padding to the left edge.
@@ -693,13 +696,13 @@ class ZoomManager {
             // Re-calculate the zoom center so that the new scroll x will be
             // on the left edge.
             if (viewLeft > 0) {
-                mZoomCenterX = viewLeft * readingScale / (readingScale - mActualScale);
+                mZoomCenterX = viewLeft * zoomScale / (zoomScale - mActualScale);
             } else {
                 mWebView.scrollBy(viewLeft, 0);
                 mZoomCenterX = 0;
             }
         }
-        startZoomAnimation(readingScale,
+        startZoomAnimation(zoomScale,
             !mWebView.getSettings().getUseFixedViewport());
     }