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/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.gecko.gfx;
import org.mozilla.gecko.AppConstants.Versions;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PointF;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.widget.EdgeEffect;
import java.lang.reflect.Field;
public class OverscrollEdgeEffect implements Overscroll {
// Used to index particular edges in the edges array
private static final int TOP = 0;
private static final int BOTTOM = 1;
private static final int LEFT = 2;
private static final int RIGHT = 3;
// All four edges of the screen
private final EdgeEffect[] mEdges = new EdgeEffect[4];
// The view we're showing this overscroll on.
private final LayerView mView;
public OverscrollEdgeEffect(final LayerView v) {
Field paintField = null;
if (Versions.feature21Plus) {
try {
paintField = EdgeEffect.class.getDeclaredField("mPaint");
paintField.setAccessible(true);
} catch (NoSuchFieldException e) {
}
}
mView = v;
Context context = v.getContext();
for (int i = 0; i < 4; i++) {
mEdges[i] = new EdgeEffect(context);
try {
if (paintField != null) {
final Paint p = (Paint) paintField.get(mEdges[i]);
// The Android EdgeEffect class uses a mode of SRC_ATOP here, which means it will only
// draw the effect where there are non-transparent pixels in the destination. Since the LayerView
// itself is fully transparent, it doesn't display at all. We need to use SRC instead.
p.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC));
}
} catch (IllegalAccessException e) {
}
}
}
@Override
public void setSize(final int width, final int height) {
mEdges[LEFT].setSize(height, width);
mEdges[RIGHT].setSize(height, width);
mEdges[TOP].setSize(width, height);
mEdges[BOTTOM].setSize(width, height);
}
private EdgeEffect getEdgeForAxisAndSide(final Axis axis, final float side) {
if (axis == Axis.Y) {
if (side < 0) {
return mEdges[TOP];
} else {
return mEdges[BOTTOM];
}
} else {
if (side < 0) {
return mEdges[LEFT];
} else {
return mEdges[RIGHT];
}
}
}
private void invalidate() {
if (Versions.feature16Plus) {
mView.postInvalidateOnAnimation();
} else {
mView.postInvalidateDelayed(10);
}
}
@Override
public void setVelocity(final float velocity, final Axis axis) {
final EdgeEffect edge = getEdgeForAxisAndSide(axis, velocity);
// If we're showing overscroll already, start fading it out.
if (!edge.isFinished()) {
edge.onRelease();
} else {
// Otherwise, show an absorb effect
edge.onAbsorb((int)velocity);
}
invalidate();
}
@Override
public void setDistance(final float distance, final Axis axis) {
// The first overscroll event often has zero distance. Throw it out
if (distance == 0.0f) {
return;
}
final EdgeEffect edge = getEdgeForAxisAndSide(axis, (int)distance);
edge.onPull(distance / (axis == Axis.X ? mView.getWidth() : mView.getHeight()));
invalidate();
}
@Override
public void draw(final Canvas canvas, final ImmutableViewportMetrics metrics) {
if (metrics == null) {
return;
}
PointF visibleEnd = mView.getDynamicToolbarAnimator().getVisibleEndOfLayerView();
// If we're pulling an edge, or fading it out, draw!
boolean invalidate = false;
if (!mEdges[TOP].isFinished()) {
invalidate |= draw(mEdges[TOP], canvas, 0, 0, 0);
}
if (!mEdges[BOTTOM].isFinished()) {
invalidate |= draw(mEdges[BOTTOM], canvas, visibleEnd.x, visibleEnd.y, 180);
}
if (!mEdges[LEFT].isFinished()) {
invalidate |= draw(mEdges[LEFT], canvas, 0, visibleEnd.y, 270);
}
if (!mEdges[RIGHT].isFinished()) {
invalidate |= draw(mEdges[RIGHT], canvas, visibleEnd.x, 0, 90);
}
// If the edge effect is animating off screen, invalidate.
if (invalidate) {
invalidate();
}
}
private static boolean draw(final EdgeEffect edge, final Canvas canvas, final float translateX, final float translateY, final float rotation) {
final int state = canvas.save();
canvas.translate(translateX, translateY);
canvas.rotate(rotation);
boolean invalidate = edge.draw(canvas);
canvas.restoreToCount(state);
return invalidate;
}
}
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