michael@0: /* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: package org.mozilla.gecko.gfx;
michael@0: 
michael@0: import android.content.Context;
michael@0: import android.graphics.Canvas;
michael@0: import android.os.Build;
michael@0: import android.widget.EdgeEffect;
michael@0: import android.view.View;
michael@0: 
michael@0: 
michael@0: public class OverscrollEdgeEffect implements Overscroll {
michael@0:     // Used to index particular edges in the edges array
michael@0:     private static final int TOP = 0;
michael@0:     private static final int BOTTOM = 1;
michael@0:     private static final int LEFT = 2;
michael@0:     private static final int RIGHT = 3;
michael@0: 
michael@0:     // All four edges of the screen
michael@0:     private final EdgeEffect[] mEdges = new EdgeEffect[4];
michael@0: 
michael@0:     // The view we're showing this overscroll on.
michael@0:     private final View mView;
michael@0: 
michael@0:     public OverscrollEdgeEffect(final View v) {
michael@0:         mView = v;
michael@0:         Context context = v.getContext();
michael@0:         for (int i = 0; i < 4; i++) {
michael@0:             mEdges[i] = new EdgeEffect(context);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     public void setSize(final int width, final int height) {
michael@0:         mEdges[LEFT].setSize(height, width);
michael@0:         mEdges[RIGHT].setSize(height, width);
michael@0:         mEdges[TOP].setSize(width, height);
michael@0:         mEdges[BOTTOM].setSize(width, height);
michael@0:     }
michael@0: 
michael@0:     private EdgeEffect getEdgeForAxisAndSide(final Axis axis, final float side) {
michael@0:         if (axis == Axis.Y) {
michael@0:             if (side < 0) {
michael@0:                 return mEdges[TOP];
michael@0:             } else {
michael@0:                 return mEdges[BOTTOM];
michael@0:             }
michael@0:         } else {
michael@0:             if (side < 0) {
michael@0:                 return mEdges[LEFT];
michael@0:             } else {
michael@0:                 return mEdges[RIGHT];
michael@0:             }
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     private void invalidate() {
michael@0:         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
michael@0:             mView.postInvalidateOnAnimation();
michael@0:         } else {
michael@0:             mView.postInvalidateDelayed(10);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     public void setVelocity(final float velocity, final Axis axis) {
michael@0:         final EdgeEffect edge = getEdgeForAxisAndSide(axis, velocity);
michael@0: 
michael@0:         // If we're showing overscroll already, start fading it out.
michael@0:         if (!edge.isFinished()) {
michael@0:             edge.onRelease();
michael@0:         } else {
michael@0:             // Otherwise, show an absorb effect
michael@0:             edge.onAbsorb((int)velocity);
michael@0:         }
michael@0: 
michael@0:         invalidate();
michael@0:     }
michael@0: 
michael@0:     public void setDistance(final float distance, final Axis axis) {
michael@0:         // The first overscroll event often has zero distance. Throw it out
michael@0:         if (distance == 0.0f) {
michael@0:             return;
michael@0:         }
michael@0: 
michael@0:         final EdgeEffect edge = getEdgeForAxisAndSide(axis, (int)distance);
michael@0:         edge.onPull(distance / (axis == Axis.X ? mView.getWidth() : mView.getHeight()));
michael@0:         invalidate();
michael@0:     }
michael@0: 
michael@0:     public void draw(final Canvas canvas, final ImmutableViewportMetrics metrics) {
michael@0:         if (metrics == null) {
michael@0:             return;
michael@0:         }
michael@0: 
michael@0:         // If we're pulling an edge, or fading it out, draw!
michael@0:         boolean invalidate = false;
michael@0:         if (!mEdges[TOP].isFinished()) {
michael@0:             invalidate |= draw(mEdges[TOP], canvas, metrics.marginLeft, metrics.marginTop, 0);
michael@0:         }
michael@0: 
michael@0:         if (!mEdges[BOTTOM].isFinished()) {
michael@0:             invalidate |= draw(mEdges[BOTTOM], canvas, mView.getWidth(), mView.getHeight(), 180);
michael@0:         }
michael@0: 
michael@0:         if (!mEdges[LEFT].isFinished()) {
michael@0:             invalidate |= draw(mEdges[LEFT], canvas, metrics.marginLeft, mView.getHeight(), 270);
michael@0:         }
michael@0: 
michael@0:         if (!mEdges[RIGHT].isFinished()) {
michael@0:             invalidate |= draw(mEdges[RIGHT], canvas, mView.getWidth(), metrics.marginTop, 90);
michael@0:         }
michael@0: 
michael@0:         // If the edge effect is animating off screen, invalidate.
michael@0:         if (invalidate) {
michael@0:             invalidate();
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     public boolean draw(final EdgeEffect edge, final Canvas canvas, final float translateX, final float translateY, final float rotation) {
michael@0:         final int state = canvas.save();
michael@0:         canvas.translate(translateX, translateY);
michael@0:         canvas.rotate(rotation);
michael@0:         boolean invalidate = edge.draw(canvas);
michael@0:         canvas.restoreToCount(state);
michael@0: 
michael@0:         return invalidate;
michael@0:     }
michael@0: }