// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package org.chromium.android_webview;
import android.content.Context;
import android.graphics.Canvas;
import android.view.View;
import android.widget.EdgeEffect;
/** This class manages the edge glow effect when a WebView is flung or pulled beyond the edges. */
class OverScrollGlow {
private View mHostView;
private EdgeEffect mEdgeGlowTop;
private EdgeEffect mEdgeGlowBottom;
private EdgeEffect mEdgeGlowLeft;
private EdgeEffect mEdgeGlowRight;
private int mOverScrollDeltaX;
private int mOverScrollDeltaY;
private boolean mShouldPull;
public OverScrollGlow(Context context, View host) {
mHostView = host;
mEdgeGlowTop = new EdgeEffect(context);
mEdgeGlowBottom = new EdgeEffect(context);
mEdgeGlowLeft = new EdgeEffect(context);
mEdgeGlowRight = new EdgeEffect(context);
}
public void setShouldPull(boolean shouldPull) {
mShouldPull = shouldPull;
}
/**
* Pull leftover touch scroll distance into one of the edge glows as appropriate.
*
* @param x Current X scroll offset
* @param y Current Y scroll offset
* @param oldX Old X scroll offset
* @param oldY Old Y scroll offset
* @param maxX Maximum range for horizontal scrolling
* @param maxY Maximum range for vertical scrolling
*/
public void pullGlow(int x, int y, int oldX, int oldY, int maxX, int maxY) {
if (!mShouldPull) return;
// Only show overscroll bars if there was no movement in any direction
// as a result of scrolling.
if (oldX == mHostView.getScrollX() && oldY == mHostView.getScrollY()) {
// Don't show left/right glows if we fit the whole content.
// Also don't show if there was vertical movement.
if (maxX > 0) {
final int pulledToX = oldX + mOverScrollDeltaX;
if (pulledToX < 0) {
// |mOverScrollDeltaX| will be negative when overscroll to the left.
mEdgeGlowLeft.onPull((float) -mOverScrollDeltaX / mHostView.getWidth());
if (!mEdgeGlowRight.isFinished()) {
mEdgeGlowRight.onRelease();
}
} else if (pulledToX > maxX) {
mEdgeGlowRight.onPull((float) mOverScrollDeltaX / mHostView.getWidth());
if (!mEdgeGlowLeft.isFinished()) {
mEdgeGlowLeft.onRelease();
}
}
mOverScrollDeltaX = 0;
}
if (maxY > 0 || mHostView.getOverScrollMode() == View.OVER_SCROLL_ALWAYS) {
final int pulledToY = oldY + mOverScrollDeltaY;
if (pulledToY < 0) {
// |mOverScrollDeltaY| will be negative when overscroll to the top.
mEdgeGlowTop.onPull((float) -mOverScrollDeltaY / mHostView.getHeight());
if (!mEdgeGlowBottom.isFinished()) {
mEdgeGlowBottom.onRelease();
}
} else if (pulledToY > maxY) {
mEdgeGlowBottom.onPull((float) mOverScrollDeltaY / mHostView.getHeight());
if (!mEdgeGlowTop.isFinished()) {
mEdgeGlowTop.onRelease();
}
}
mOverScrollDeltaY = 0;
}
}
}
/**
* Absorb leftover fling velocity into one of the edge glows as appropriate.
*
* @param x Current X scroll offset
* @param y Current Y scroll offset
* @param oldX Old X scroll offset
* @param oldY Old Y scroll offset
* @param rangeX Maximum range for horizontal scrolling
* @param rangeY Maximum range for vertical scrolling
* @param currentFlingVelocity Current fling velocity
*/
public void absorbGlow(
int x, int y, int oldX, int oldY, int rangeX, int rangeY, float currentFlingVelocity) {
if (mShouldPull) {
// Not absorb the glow because the user is pulling the glow now.
// TODO(hush): crbug.com/501556. Do not use "mShouldPull" to switch
// between absorbGlow and pullGlow. Use the velocity instead.
return;
}
if (rangeY > 0 || mHostView.getOverScrollMode() == View.OVER_SCROLL_ALWAYS) {
if (y < 0 && oldY >= 0) {
mEdgeGlowTop.onAbsorb((int) currentFlingVelocity);
if (!mEdgeGlowBottom.isFinished()) {
mEdgeGlowBottom.onRelease();
}
} else if (y > rangeY && oldY <= rangeY) {
mEdgeGlowBottom.onAbsorb((int) currentFlingVelocity);
if (!mEdgeGlowTop.isFinished()) {
mEdgeGlowTop.onRelease();
}
}
}
if (rangeX > 0) {
if (x < 0 && oldX >= 0) {
mEdgeGlowLeft.onAbsorb((int) currentFlingVelocity);
if (!mEdgeGlowRight.isFinished()) {
mEdgeGlowRight.onRelease();
}
} else if (x > rangeX && oldX <= rangeX) {
mEdgeGlowRight.onAbsorb((int) currentFlingVelocity);
if (!mEdgeGlowLeft.isFinished()) {
mEdgeGlowLeft.onRelease();
}
}
}
}
/**
* Set touch delta values indicating the current amount of overscroll.
*
* @param deltaX
* @param deltaY
*/
public void setOverScrollDeltas(int deltaX, int deltaY) {
mOverScrollDeltaX += deltaX;
mOverScrollDeltaY += deltaY;
}
/**
* Draw the glow effect along the sides of the widget.
*
* @param canvas Canvas to draw into, transformed into view coordinates.
* @param maxScrollX maximum horizontal scroll offset
* @param maxScrollY maximum vertical scroll offset
* @return true if glow effects are still animating and the view should invalidate again.
*/
public boolean drawEdgeGlows(Canvas canvas, int maxScrollX, int maxScrollY) {
final int scrollX = mHostView.getScrollX();
final int scrollY = mHostView.getScrollY();
final int width = mHostView.getWidth();
int height = mHostView.getHeight();
boolean invalidateForGlow = false;
if (!mEdgeGlowTop.isFinished()) {
final int restoreCount = canvas.save();
canvas.translate(scrollX, Math.min(0, scrollY));
mEdgeGlowTop.setSize(width, height);
invalidateForGlow |= mEdgeGlowTop.draw(canvas);
canvas.restoreToCount(restoreCount);
}
if (!mEdgeGlowBottom.isFinished()) {
final int restoreCount = canvas.save();
canvas.translate(-width + scrollX, Math.max(maxScrollY, scrollY) + height);
canvas.rotate(180, width, 0);
mEdgeGlowBottom.setSize(width, height);
invalidateForGlow |= mEdgeGlowBottom.draw(canvas);
canvas.restoreToCount(restoreCount);
}
if (!mEdgeGlowLeft.isFinished()) {
final int restoreCount = canvas.save();
canvas.rotate(270);
canvas.translate(-height - scrollY, Math.min(0, scrollX));
mEdgeGlowLeft.setSize(height, width);
invalidateForGlow |= mEdgeGlowLeft.draw(canvas);
canvas.restoreToCount(restoreCount);
}
if (!mEdgeGlowRight.isFinished()) {
final int restoreCount = canvas.save();
canvas.rotate(90);
canvas.translate(scrollY, -(Math.max(scrollX, maxScrollX) + width));
mEdgeGlowRight.setSize(height, width);
invalidateForGlow |= mEdgeGlowRight.draw(canvas);
canvas.restoreToCount(restoreCount);
}
return invalidateForGlow;
}
/** @return True if any glow is still animating */
public boolean isAnimating() {
return (!mEdgeGlowTop.isFinished()
|| !mEdgeGlowBottom.isFinished()
|| !mEdgeGlowLeft.isFinished()
|| !mEdgeGlowRight.isFinished());
}
/** Release all glows from any touch pulls in progress. */
public void releaseAll() {
mEdgeGlowTop.onRelease();
mEdgeGlowBottom.onRelease();
mEdgeGlowLeft.onRelease();
mEdgeGlowRight.onRelease();
}
}
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