Home | History | Annotate | Download | only in view 
      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.view;
     18 
     19 import com.android.resources.Density;
     20 import com.android.tools.layoutlib.annotations.LayoutlibDelegate;
     21 
     22 import android.graphics.Bitmap;
     23 import android.graphics.Bitmap_Delegate;
     24 import android.graphics.Canvas;
     25 import android.graphics.Outline;
     26 import android.graphics.Path_Delegate;
     27 import android.graphics.Rect;
     28 import android.graphics.Region.Op;
     29 import android.view.animation.Transformation;
     30 
     31 import java.awt.Graphics2D;
     32 import java.awt.image.BufferedImage;
     33 
     34 /**
     35  * Delegate used to provide new implementation of a select few methods of {@link ViewGroup}
     36  * <p/>
     37  * Through the layoutlib_create tool, the original  methods of ViewGroup have been replaced by calls
     38  * to methods of the same name in this delegate class.
     39  */
     40 public class ViewGroup_Delegate {
     41 
     42     /**
     43      * Overrides the original drawChild call in ViewGroup to draw the shadow.
     44      */
     45     @LayoutlibDelegate
     46     /*package*/ static boolean drawChild(ViewGroup thisVG, Canvas canvas, View child,
     47             long drawingTime) {
     48         if (child.getZ() > thisVG.getZ()) {
     49             // The background's bounds are set lazily. Make sure they are set correctly so that
     50             // the outline obtained is correct.
     51             child.setBackgroundBounds();
     52             ViewOutlineProvider outlineProvider = child.getOutlineProvider();
     53             Outline outline = child.mAttachInfo.mTmpOutline;
     54             outlineProvider.getOutline(child, outline);
     55             if (outline.mPath != null || (outline.mRect != null && !outline.mRect.isEmpty())) {
     56                 int restoreTo = transformCanvas(thisVG, canvas, child);
     57                 drawShadow(thisVG, canvas, child, outline);
     58                 canvas.restoreToCount(restoreTo);
     59             }
     60         }
     61         return thisVG.drawChild_Original(canvas, child, drawingTime);
     62     }
     63 
     64     private static void drawShadow(ViewGroup parent, Canvas canvas, View child,
     65             Outline outline) {
     66         float elevation = getElevation(child, parent);
     67         if(outline.mRect != null) {
     68             RectShadowPainter.paintShadow(outline, elevation, canvas);
     69             return;
     70         }
     71         BufferedImage shadow = null;
     72         if (outline.mPath != null) {
     73             shadow = getPathShadow(outline, canvas, elevation);
     74         }
     75         if (shadow == null) {
     76             return;
     77         }
     78         Bitmap bitmap = Bitmap_Delegate.createBitmap(shadow, false,
     79                 Density.getEnum(canvas.getDensity()));
     80         Rect clipBounds = canvas.getClipBounds();
     81         Rect newBounds = new Rect(clipBounds);
     82         newBounds.inset((int)-elevation, (int)-elevation);
     83         canvas.clipRect(newBounds, Op.REPLACE);
     84         canvas.drawBitmap(bitmap, 0, 0, null);
     85         canvas.clipRect(clipBounds, Op.REPLACE);
     86     }
     87 
     88     private static float getElevation(View child, ViewGroup parent) {
     89         return child.getZ() - parent.getZ();
     90     }
     91 
     92     private static BufferedImage getPathShadow(Outline outline, Canvas canvas, float elevation) {
     93         Rect clipBounds = canvas.getClipBounds();
     94         if (clipBounds.isEmpty()) {
     95           return null;
     96         }
     97         BufferedImage image = new BufferedImage(clipBounds.width(), clipBounds.height(),
     98                 BufferedImage.TYPE_INT_ARGB);
     99         Graphics2D graphics = image.createGraphics();
    100         graphics.draw(Path_Delegate.getDelegate(outline.mPath.mNativePath).getJavaShape());
    101         graphics.dispose();
    102         return ShadowPainter.createDropShadow(image, (int) elevation);
    103     }
    104 
    105     // Copied from android.view.View#draw(Canvas, ViewGroup, long) and removed code paths
    106     // which were never taken. Ideally, we should hook up the shadow code in the same method so
    107     // that we don't have to transform the canvas twice.
    108     private static int transformCanvas(ViewGroup thisVG, Canvas canvas, View child) {
    109         final int restoreTo = canvas.save();
    110         final boolean childHasIdentityMatrix = child.hasIdentityMatrix();
    111         int flags = thisVG.mGroupFlags;
    112         Transformation transformToApply = null;
    113         boolean concatMatrix = false;
    114         if ((flags & ViewGroup.FLAG_SUPPORT_STATIC_TRANSFORMATIONS) != 0) {
    115             final Transformation t = thisVG.getChildTransformation();
    116             final boolean hasTransform = thisVG.getChildStaticTransformation(child, t);
    117             if (hasTransform) {
    118                 final int transformType = t.getTransformationType();
    119                 transformToApply = transformType != Transformation.TYPE_IDENTITY ? t : null;
    120                 concatMatrix = (transformType & Transformation.TYPE_MATRIX) != 0;
    121             }
    122         }
    123         concatMatrix |= childHasIdentityMatrix;
    124 
    125         child.computeScroll();
    126         int sx = child.mScrollX;
    127         int sy = child.mScrollY;
    128 
    129         canvas.translate(child.mLeft - sx, child.mTop - sy);
    130         float alpha = child.getAlpha() * child.getTransitionAlpha();
    131 
    132         if (transformToApply != null || alpha < 1 || !childHasIdentityMatrix) {
    133             if (transformToApply != null || !childHasIdentityMatrix) {
    134                 int transX = -sx;
    135                 int transY = -sy;
    136 
    137                 if (transformToApply != null) {
    138                     if (concatMatrix) {
    139                         // Undo the scroll translation, apply the transformation matrix,
    140                         // then redo the scroll translate to get the correct result.
    141                         canvas.translate(-transX, -transY);
    142                         canvas.concat(transformToApply.getMatrix());
    143                         canvas.translate(transX, transY);
    144                     }
    145                     if (!childHasIdentityMatrix) {
    146                         canvas.translate(-transX, -transY);
    147                         canvas.concat(child.getMatrix());
    148                         canvas.translate(transX, transY);
    149                     }
    150                 }
    151 
    152             }
    153         }
    154         return restoreTo;
    155     }
    156 }
    157