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      1 /*
      2  * Copyright (C) 2010 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 android.graphics.Bitmap;
     20 import android.graphics.Canvas;
     21 import android.graphics.Paint;
     22 import android.graphics.Rect;
     23 
     24 /**
     25  * Hardware accelerated canvas.
     26  *
     27  * @hide
     28  */
     29 public abstract class HardwareCanvas extends Canvas {
     30     private String mName;
     31 
     32     @Override
     33     public boolean isHardwareAccelerated() {
     34         return true;
     35     }
     36 
     37     @Override
     38     public void setBitmap(Bitmap bitmap) {
     39         throw new UnsupportedOperationException();
     40     }
     41 
     42     /**
     43      * Specifies the name of this canvas. Naming the canvas is entirely
     44      * optional but can be useful for debugging purposes.
     45      *
     46      * @param name The name of the canvas, can be null
     47      *
     48      * @see #getName()
     49      *
     50      * @hide
     51      */
     52     public void setName(String name) {
     53         mName = name;
     54     }
     55 
     56     /**
     57      * Returns the name of this canvas.
     58      *
     59      * @return The name of the canvas or null
     60      *
     61      * @see #setName(String)
     62      *
     63      * @hide
     64      */
     65     public String getName() {
     66         return mName;
     67     }
     68 
     69     /**
     70      * Invoked before any drawing operation is performed in this canvas.
     71      *
     72      * @param dirty The dirty rectangle to update, can be null.
     73      * @return {@link DisplayList#STATUS_DREW} if anything was drawn (such as a call to clear
     74      *         the canvas).
     75      *
     76      * @hide
     77      */
     78     public abstract int onPreDraw(Rect dirty);
     79 
     80     /**
     81      * Invoked after all drawing operation have been performed.
     82      *
     83      * @hide
     84      */
     85     public abstract void onPostDraw();
     86 
     87     /**
     88      * Draws the specified display list onto this canvas. The display list can only
     89      * be drawn if {@link android.view.DisplayList#isValid()} returns true.
     90      *
     91      * @param displayList The display list to replay.
     92      */
     93     public void drawDisplayList(DisplayList displayList) {
     94         drawDisplayList(displayList, null, DisplayList.FLAG_CLIP_CHILDREN);
     95     }
     96 
     97     /**
     98      * Draws the specified display list onto this canvas.
     99      *
    100      * @param displayList The display list to replay.
    101      * @param dirty The dirty region to redraw in the next pass, matters only
    102      *        if this method returns {@link DisplayList#STATUS_DRAW}, can be null.
    103      * @param flags Optional flags about drawing, see {@link DisplayList} for
    104      *              the possible flags.
    105      *
    106      * @return One of {@link DisplayList#STATUS_DONE}, {@link DisplayList#STATUS_DRAW}, or
    107      *         {@link DisplayList#STATUS_INVOKE}, or'd with {@link DisplayList#STATUS_DREW}
    108      *         if anything was drawn.
    109      *
    110      * @hide
    111      */
    112     public abstract int drawDisplayList(DisplayList displayList, Rect dirty, int flags);
    113 
    114     /**
    115      * Outputs the specified display list to the log. This method exists for use by
    116      * tools to output display lists for selected nodes to the log.
    117      *
    118      * @param displayList The display list to be logged.
    119      *
    120      * @hide
    121      */
    122     abstract void outputDisplayList(DisplayList displayList);
    123 
    124     /**
    125      * Draws the specified layer onto this canvas.
    126      *
    127      * @param layer The layer to composite on this canvas
    128      * @param x The left coordinate of the layer
    129      * @param y The top coordinate of the layer
    130      * @param paint The paint used to draw the layer
    131      *
    132      * @hide
    133      */
    134     abstract void drawHardwareLayer(HardwareLayer layer, float x, float y, Paint paint);
    135 
    136     /**
    137      * Calls the function specified with the drawGLFunction function pointer. This is
    138      * functionality used by webkit for calling into their renderer from our display lists.
    139      * This function may return true if an invalidation is needed after the call.
    140      *
    141      * @param drawGLFunction A native function pointer
    142      *
    143      * @return One of {@link DisplayList#STATUS_DONE}, {@link DisplayList#STATUS_DRAW} or
    144      *         {@link DisplayList#STATUS_INVOKE}
    145      *
    146      * @hide
    147      */
    148     public int callDrawGLFunction(int drawGLFunction) {
    149         // Noop - this is done in the display list recorder subclass
    150         return DisplayList.STATUS_DONE;
    151     }
    152 
    153     /**
    154      * Invoke all the functors who requested to be invoked during the previous frame.
    155      *
    156      * @param dirty The region to redraw when the functors return {@link DisplayList#STATUS_DRAW}
    157      *
    158      * @return One of {@link DisplayList#STATUS_DONE}, {@link DisplayList#STATUS_DRAW} or
    159      *         {@link DisplayList#STATUS_INVOKE}
    160      *
    161      * @hide
    162      */
    163     public int invokeFunctors(Rect dirty) {
    164         return DisplayList.STATUS_DONE;
    165     }
    166 
    167     /**
    168      * Detaches the specified functor from the current functor execution queue.
    169      *
    170      * @param functor The native functor to remove from the execution queue.
    171      *
    172      * @see #invokeFunctors(android.graphics.Rect)
    173      * @see #callDrawGLFunction(int)
    174      * @see #detachFunctor(int)
    175      *
    176      * @hide
    177      */
    178     abstract void detachFunctor(int functor);
    179 
    180     /**
    181      * Attaches the specified functor to the current functor execution queue.
    182      *
    183      * @param functor The native functor to add to the execution queue.
    184      *
    185      * @see #invokeFunctors(android.graphics.Rect)
    186      * @see #callDrawGLFunction(int)
    187      * @see #detachFunctor(int)
    188      *
    189      * @hide
    190      */
    191     abstract void attachFunctor(int functor);
    192 
    193     /**
    194      * Indicates that the specified layer must be updated as soon as possible.
    195      *
    196      * @param layer The layer to update
    197      *
    198      * @see #clearLayerUpdates()
    199      *
    200      * @hide
    201      */
    202     abstract void pushLayerUpdate(HardwareLayer layer);
    203 
    204     /**
    205      * Removes all enqueued layer updates.
    206      *
    207      * @see #pushLayerUpdate(HardwareLayer)
    208      *
    209      * @hide
    210      */
    211     abstract void clearLayerUpdates();
    212 }
    213