refactor drawing to support layers

Drawing elements that appear atop or below layers need to be
drawn both in the proper order and with the correct canvas to
respect clipping and the matrix.

The logic of what to draw is still in WebView.java, but the
actual drawing calls are now triggered inside the layer code.

This still draws layers incorrectly after drawing the history;
will fix this in a future CL.

Move drawing to WebView.cpp.
Use inverseScale to simplify viewPort metrics.
Remove root layer; let WebView.cpp handle it exclusively.

Requires companion fix in external/webkit.

http://b/2457316
http://b/2454127
http://b/2454149

1 files changed, 46 insertions, 50 deletions

diff --git a/core/java/android/webkit/WebView.java b/core/java/android/webkit/WebView.java
index 67543aa..c1a4a49 100644
--- a/core/java/android/webkit/WebView.java
+++ b/core/java/android/webkit/WebView.java
@@ -213,7 +213,6 @@ public class WebView extends AbsoluteLayout
     static private final boolean AUTO_REDRAW_HACK = false;
     // true means redraw the screen all-the-time. Only with AUTO_REDRAW_HACK
     private boolean mAutoRedraw;
-    private int mRootLayer; // C++ pointer to the root layer
 
     static final String LOGTAG = "webview";
 
@@ -618,6 +617,12 @@ public class WebView extends AbsoluteLayout
     private static final int SNAP_Y = 4; // may be combined with SNAP_LOCK
     private boolean mSnapPositive;
 
+    // keep these in sync with their counterparts in WebView.cpp
+    private static final int DRAW_EXTRAS_NONE = 0;
+    private static final int DRAW_EXTRAS_FIND = 1;
+    private static final int DRAW_EXTRAS_SELECTION = 2;
+    private static final int DRAW_EXTRAS_CURSOR_RING = 3;
+
     // Used to match key downs and key ups
     private boolean mGotKeyDown;
 
@@ -1306,6 +1311,7 @@ public class WebView extends AbsoluteLayout
                 // onSizeChanged() is called, the rest will be set
                 // correctly
                 mActualScale = scale;
+                mInvActualScale = 1 / scale;
                 mTextWrapScale = b.getFloat("textwrapScale", scale);
                 mInZoomOverview = b.getBoolean("overview");
                 invalidate();
@@ -3116,7 +3122,7 @@ public class WebView extends AbsoluteLayout
         int mScrollY;
         int mWidth;
         int mHeight;
-        float mScale;
+        float mInvScale;
     }
 
     private Metrics getViewMetrics() {
@@ -3125,23 +3131,21 @@ public class WebView extends AbsoluteLayout
         metrics.mScrollY = computeVerticalScrollOffset();
         metrics.mWidth = getWidth();
         metrics.mHeight = getHeight() - getVisibleTitleHeight();
-        metrics.mScale = mActualScale;
+        metrics.mInvScale = mInvActualScale;
         return metrics;
     }
 
-    private void drawLayers(Canvas canvas) {
-        if (mRootLayer != 0) {
-            // Currently for each draw we compute the animation values;
-            // We may in the future decide to do that independently.
-            if (nativeEvaluateLayersAnimations(mRootLayer)) {
-                // If we have unfinished (or unstarted) animations,
-                // we ask for a repaint.
-                invalidate();
-            }
-
-            // We can now draw the layers.
-            nativeDrawLayers(mRootLayer, canvas);
+    private void drawExtras(Canvas canvas, int extras) {
+        if (mNativeClass == 0) return;
+        // Currently for each draw we compute the animation values;
+        // We may in the future decide to do that independently.
+        if (nativeEvaluateLayersAnimations()) {
+            // If we have unfinished (or unstarted) animations,
+            // we ask for a repaint.
+            invalidate();
         }
+
+        nativeDrawExtras(canvas, extras);
     }
 
     private void drawCoreAndCursorRing(Canvas canvas, int color,
@@ -3149,7 +3153,7 @@ public class WebView extends AbsoluteLayout
         if (mDrawHistory) {
             canvas.scale(mActualScale, mActualScale);
             canvas.drawPicture(mHistoryPicture);
-            drawLayers(canvas);
+            drawExtras(canvas, DRAW_EXTRAS_NONE);
             return;
         }
 
@@ -3228,27 +3232,29 @@ public class WebView extends AbsoluteLayout
 
         mWebViewCore.drawContentPicture(canvas, color,
                 (animateZoom || mPreviewZoomOnly), animateScroll);
-        boolean cursorIsInLayer = nativeCursorIsInLayer();
-        if (drawCursorRing && !cursorIsInLayer) {
-            nativeDrawCursorRing(canvas);
-        }
-        // When the FindDialog is up, only draw the matches if we are not in
-        // the process of scrolling them into view.
-        if (mFindIsUp && !animateScroll) {
-            nativeDrawMatches(canvas);
-        }
-        drawLayers(canvas);
-
         if (mNativeClass == 0) return;
-        if (mShiftIsPressed && !(animateZoom || mPreviewZoomOnly)) {
-            if (mTouchSelection || mExtendSelection) {
-                nativeDrawSelectionRegion(canvas);
-            }
-            if (!mTouchSelection) {
-                nativeDrawSelectionPointer(canvas, mInvActualScale, mSelectX,
-                        mSelectY - getTitleHeight(), mExtendSelection);
+        // decide which adornments to draw
+        int extras = DRAW_EXTRAS_NONE;
+        if (mFindIsUp) {
+            // When the FindDialog is up, only draw the matches if we are not in
+            // the process of scrolling them into view.
+            if (!animateScroll) {
+                extras = DRAW_EXTRAS_FIND;
+            }
+        } else if (mShiftIsPressed) {
+            if (!animateZoom && !mPreviewZoomOnly) {
+                extras = DRAW_EXTRAS_SELECTION;
+                nativeSetSelectionRegion(mTouchSelection || mExtendSelection);
+                nativeSetSelectionPointer(!mTouchSelection, mInvActualScale,
+                        mSelectX, mSelectY - getTitleHeight(),
+                        mExtendSelection);
             }
         } else if (drawCursorRing) {
+            extras = DRAW_EXTRAS_CURSOR_RING;
+        }
+        drawExtras(canvas, extras);
+
+        if (extras == DRAW_EXTRAS_CURSOR_RING) {
             if (mTouchMode == TOUCH_SHORTPRESS_START_MODE) {
                 mTouchMode = TOUCH_SHORTPRESS_MODE;
                 HitTestResult hitTest = getHitTestResult();
@@ -3259,7 +3265,6 @@ public class WebView extends AbsoluteLayout
                             LONG_PRESS_TIMEOUT);
                 }
             }
-            if (cursorIsInLayer) nativeDrawCursorRing(canvas);
         }
         if (mFocusSizeChanged) {
             mFocusSizeChanged = false;
@@ -6001,12 +6006,7 @@ public class WebView extends AbsoluteLayout
                     break;
                 }
                 case SET_ROOT_LAYER_MSG_ID: {
-                    int oldLayer = mRootLayer;
-                    mRootLayer = msg.arg1;
-                    nativeSetRootLayer(mRootLayer);
-                    if (oldLayer > 0) {
-                        nativeDestroyLayer(oldLayer);
-                    }
+                    nativeSetRootLayer(msg.arg1);
                     invalidate();
                     break;
                 }
@@ -6766,7 +6766,6 @@ public class WebView extends AbsoluteLayout
     /* package */ native boolean nativeCursorMatchesFocus();
     private native boolean  nativeCursorIntersects(Rect visibleRect);
     private native boolean  nativeCursorIsAnchor();
-    private native boolean  nativeCursorIsInLayer();
     private native boolean  nativeCursorIsTextInput();
     private native Point    nativeCursorPosition();
     private native String   nativeCursorText();
@@ -6777,14 +6776,8 @@ public class WebView extends AbsoluteLayout
     private native boolean  nativeCursorWantsKeyEvents();
     private native void     nativeDebugDump();
     private native void     nativeDestroy();
-    private native void     nativeDrawCursorRing(Canvas content);
-    private native void     nativeDestroyLayer(int layer);
-    private native boolean  nativeEvaluateLayersAnimations(int layer);
-    private native void     nativeDrawLayers(int layer, Canvas canvas);
-    private native void     nativeDrawMatches(Canvas canvas);
-    private native void     nativeDrawSelectionPointer(Canvas content,
-            float scale, int x, int y, boolean extendSelection);
-    private native void     nativeDrawSelectionRegion(Canvas content);
+    private native boolean  nativeEvaluateLayersAnimations();
+    private native void     nativeDrawExtras(Canvas canvas, int extra);
     private native void     nativeDumpDisplayTree(String urlOrNull);
     private native int      nativeFindAll(String findLower, String findUpper);
     private native void     nativeFindNext(boolean forward);
@@ -6831,6 +6824,9 @@ public class WebView extends AbsoluteLayout
     private native void     nativeSetFollowedLink(boolean followed);
     private native void     nativeSetHeightCanMeasure(boolean measure);
     private native void     nativeSetRootLayer(int layer);
+    private native void     nativeSetSelectionPointer(boolean set,
+            float scale, int x, int y, boolean extendSelection);
+    private native void     nativeSetSelectionRegion(boolean set);
     private native int      nativeTextGeneration();
     // Never call this version except by updateCachedTextfield(String) -
     // we always want to pass in our generation number.