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      1 /*
      2  * Copyright (C) 2011 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 com.android.gallery3d.ui;
     18 
     19 import android.content.Context;
     20 import android.opengl.Matrix;
     21 
     22 import com.android.gallery3d.glrenderer.GLCanvas;
     23 
     24 // EdgeView draws EdgeEffect (blue glow) at four sides of the view.
     25 public class EdgeView extends GLView {
     26     @SuppressWarnings("unused")
     27     private static final String TAG = "EdgeView";
     28 
     29     public static final int INVALID_DIRECTION = -1;
     30     public static final int TOP = 0;
     31     public static final int LEFT = 1;
     32     public static final int BOTTOM = 2;
     33     public static final int RIGHT = 3;
     34 
     35     // Each edge effect has a transform matrix, and each matrix has 16 elements.
     36     // We put all the elements in one array. These constants specify the
     37     // starting index of each matrix.
     38     private static final int TOP_M = TOP * 16;
     39     private static final int LEFT_M = LEFT * 16;
     40     private static final int BOTTOM_M = BOTTOM * 16;
     41     private static final int RIGHT_M = RIGHT * 16;
     42 
     43     private EdgeEffect[] mEffect = new EdgeEffect[4];
     44     private float[] mMatrix = new float[4 * 16];
     45 
     46     public EdgeView(Context context) {
     47         for (int i = 0; i < 4; i++) {
     48             mEffect[i] = new EdgeEffect(context);
     49         }
     50     }
     51 
     52     @Override
     53     protected void onLayout(
     54             boolean changeSize, int left, int top, int right, int bottom) {
     55         if (!changeSize) return;
     56 
     57         int w = right - left;
     58         int h = bottom - top;
     59         for (int i = 0; i < 4; i++) {
     60             if ((i & 1) == 0) {  // top or bottom
     61                 mEffect[i].setSize(w, h);
     62             } else {  // left or right
     63                 mEffect[i].setSize(h, w);
     64             }
     65         }
     66 
     67         // Set up transforms for the four edges. Without transforms an
     68         // EdgeEffect draws the TOP edge from (0, 0) to (w, Y * h) where Y
     69         // is some factor < 1. For other edges we need to move, rotate, and
     70         // flip the effects into proper places.
     71         Matrix.setIdentityM(mMatrix, TOP_M);
     72         Matrix.setIdentityM(mMatrix, LEFT_M);
     73         Matrix.setIdentityM(mMatrix, BOTTOM_M);
     74         Matrix.setIdentityM(mMatrix, RIGHT_M);
     75 
     76         Matrix.rotateM(mMatrix, LEFT_M, 90, 0, 0, 1);
     77         Matrix.scaleM(mMatrix, LEFT_M, 1, -1, 1);
     78 
     79         Matrix.translateM(mMatrix, BOTTOM_M, 0, h, 0);
     80         Matrix.scaleM(mMatrix, BOTTOM_M, 1, -1, 1);
     81 
     82         Matrix.translateM(mMatrix, RIGHT_M, w, 0, 0);
     83         Matrix.rotateM(mMatrix, RIGHT_M, 90, 0, 0, 1);
     84     }
     85 
     86     @Override
     87     protected void render(GLCanvas canvas) {
     88         super.render(canvas);
     89         boolean more = false;
     90         for (int i = 0; i < 4; i++) {
     91             canvas.save(GLCanvas.SAVE_FLAG_MATRIX);
     92             canvas.multiplyMatrix(mMatrix, i * 16);
     93             more |= mEffect[i].draw(canvas);
     94             canvas.restore();
     95         }
     96         if (more) {
     97             invalidate();
     98         }
     99     }
    100 
    101     // Called when the content is pulled away from the edge.
    102     // offset is in pixels. direction is one of {TOP, LEFT, BOTTOM, RIGHT}.
    103     public void onPull(int offset, int direction) {
    104         int fullLength = ((direction & 1) == 0) ? getWidth() : getHeight();
    105         mEffect[direction].onPull((float)offset / fullLength);
    106         if (!mEffect[direction].isFinished()) {
    107             invalidate();
    108         }
    109     }
    110 
    111     // Call when the object is released after being pulled.
    112     public void onRelease() {
    113         boolean more = false;
    114         for (int i = 0; i < 4; i++) {
    115             mEffect[i].onRelease();
    116             more |= !mEffect[i].isFinished();
    117         }
    118         if (more) {
    119             invalidate();
    120         }
    121     }
    122 
    123     // Call when the effect absorbs an impact at the given velocity.
    124     // Used when a fling reaches the scroll boundary. velocity is in pixels
    125     // per second. direction is one of {TOP, LEFT, BOTTOM, RIGHT}.
    126     public void onAbsorb(int velocity, int direction) {
    127         mEffect[direction].onAbsorb(velocity);
    128         if (!mEffect[direction].isFinished()) {
    129             invalidate();
    130         }
    131     }
    132 }
    133