diff options
Diffstat (limited to 'src/com/android/launcher3/util/LauncherEdgeEffect.java')
-rw-r--r-- | src/com/android/launcher3/util/LauncherEdgeEffect.java | 365 |
1 files changed, 365 insertions, 0 deletions
diff --git a/src/com/android/launcher3/util/LauncherEdgeEffect.java b/src/com/android/launcher3/util/LauncherEdgeEffect.java new file mode 100644 index 000000000..3e3b255ad --- /dev/null +++ b/src/com/android/launcher3/util/LauncherEdgeEffect.java @@ -0,0 +1,365 @@ +/* + * Copyright (C) 2015 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package com.android.launcher3.util; + +import android.graphics.Canvas; +import android.graphics.Paint; +import android.graphics.Rect; +import android.view.animation.AnimationUtils; +import android.view.animation.DecelerateInterpolator; +import android.view.animation.Interpolator; + +/** + * This class differs from the framework {@link android.widget.EdgeEffect}: + * 1) It does not use PorterDuffXfermode + * 2) The width to radius factor is smaller (0.5 instead of 0.75) + */ +public class LauncherEdgeEffect { + + // Time it will take the effect to fully recede in ms + private static final int RECEDE_TIME = 600; + + // Time it will take before a pulled glow begins receding in ms + private static final int PULL_TIME = 167; + + // Time it will take in ms for a pulled glow to decay to partial strength before release + private static final int PULL_DECAY_TIME = 2000; + + private static final float MAX_ALPHA = 0.5f; + + private static final float MAX_GLOW_SCALE = 2.f; + + private static final float PULL_GLOW_BEGIN = 0.f; + + // Minimum velocity that will be absorbed + private static final int MIN_VELOCITY = 100; + // Maximum velocity, clamps at this value + private static final int MAX_VELOCITY = 10000; + + private static final float EPSILON = 0.001f; + + private static final double ANGLE = Math.PI / 6; + private static final float SIN = (float) Math.sin(ANGLE); + private static final float COS = (float) Math.cos(ANGLE); + + private float mGlowAlpha; + private float mGlowScaleY; + + private float mGlowAlphaStart; + private float mGlowAlphaFinish; + private float mGlowScaleYStart; + private float mGlowScaleYFinish; + + private long mStartTime; + private float mDuration; + + private final Interpolator mInterpolator; + + private static final int STATE_IDLE = 0; + private static final int STATE_PULL = 1; + private static final int STATE_ABSORB = 2; + private static final int STATE_RECEDE = 3; + private static final int STATE_PULL_DECAY = 4; + + private static final float PULL_DISTANCE_ALPHA_GLOW_FACTOR = 0.8f; + + private static final int VELOCITY_GLOW_FACTOR = 6; + + private int mState = STATE_IDLE; + + private float mPullDistance; + + private final Rect mBounds = new Rect(); + private final Paint mPaint = new Paint(); + private float mRadius; + private float mBaseGlowScale; + private float mDisplacement = 0.5f; + private float mTargetDisplacement = 0.5f; + + /** + * Construct a new EdgeEffect with a theme appropriate for the provided context. + */ + public LauncherEdgeEffect() { + mPaint.setAntiAlias(true); + mPaint.setStyle(Paint.Style.FILL); + mInterpolator = new DecelerateInterpolator(); + } + + /** + * Set the size of this edge effect in pixels. + * + * @param width Effect width in pixels + * @param height Effect height in pixels + */ + public void setSize(int width, int height) { + final float r = width * 0.5f / SIN; + final float y = COS * r; + final float h = r - y; + final float or = height * 0.75f / SIN; + final float oy = COS * or; + final float oh = or - oy; + + mRadius = r; + mBaseGlowScale = h > 0 ? Math.min(oh / h, 1.f) : 1.f; + + mBounds.set(mBounds.left, mBounds.top, width, (int) Math.min(height, h)); + } + + /** + * Reports if this EdgeEffect's animation is finished. If this method returns false + * after a call to {@link #draw(Canvas)} the host widget should schedule another + * drawing pass to continue the animation. + * + * @return true if animation is finished, false if drawing should continue on the next frame. + */ + public boolean isFinished() { + return mState == STATE_IDLE; + } + + /** + * Immediately finish the current animation. + * After this call {@link #isFinished()} will return true. + */ + public void finish() { + mState = STATE_IDLE; + } + + /** + * A view should call this when content is pulled away from an edge by the user. + * This will update the state of the current visual effect and its associated animation. + * The host view should always {@link android.view.View#invalidate()} after this + * and draw the results accordingly. + * + * <p>Views using EdgeEffect should favor {@link #onPull(float, float)} when the displacement + * of the pull point is known.</p> + * + * @param deltaDistance Change in distance since the last call. Values may be 0 (no change) to + * 1.f (full length of the view) or negative values to express change + * back toward the edge reached to initiate the effect. + */ + public void onPull(float deltaDistance) { + onPull(deltaDistance, 0.5f); + } + + /** + * A view should call this when content is pulled away from an edge by the user. + * This will update the state of the current visual effect and its associated animation. + * The host view should always {@link android.view.View#invalidate()} after this + * and draw the results accordingly. + * + * @param deltaDistance Change in distance since the last call. Values may be 0 (no change) to + * 1.f (full length of the view) or negative values to express change + * back toward the edge reached to initiate the effect. + * @param displacement The displacement from the starting side of the effect of the point + * initiating the pull. In the case of touch this is the finger position. + * Values may be from 0-1. + */ + public void onPull(float deltaDistance, float displacement) { + final long now = AnimationUtils.currentAnimationTimeMillis(); + mTargetDisplacement = displacement; + if (mState == STATE_PULL_DECAY && now - mStartTime < mDuration) { + return; + } + if (mState != STATE_PULL) { + mGlowScaleY = Math.max(PULL_GLOW_BEGIN, mGlowScaleY); + } + mState = STATE_PULL; + + mStartTime = now; + mDuration = PULL_TIME; + + mPullDistance += deltaDistance; + + final float absdd = Math.abs(deltaDistance); + mGlowAlpha = mGlowAlphaStart = Math.min(MAX_ALPHA, + mGlowAlpha + (absdd * PULL_DISTANCE_ALPHA_GLOW_FACTOR)); + + if (mPullDistance == 0) { + mGlowScaleY = mGlowScaleYStart = 0; + } else { + final float scale = (float) (Math.max(0, 1 - 1 / + Math.sqrt(Math.abs(mPullDistance) * mBounds.height()) - 0.3d) / 0.7d); + + mGlowScaleY = mGlowScaleYStart = scale; + } + + mGlowAlphaFinish = mGlowAlpha; + mGlowScaleYFinish = mGlowScaleY; + } + + /** + * Call when the object is released after being pulled. + * This will begin the "decay" phase of the effect. After calling this method + * the host view should {@link android.view.View#invalidate()} and thereby + * draw the results accordingly. + */ + public void onRelease() { + mPullDistance = 0; + + if (mState != STATE_PULL && mState != STATE_PULL_DECAY) { + return; + } + + mState = STATE_RECEDE; + mGlowAlphaStart = mGlowAlpha; + mGlowScaleYStart = mGlowScaleY; + + mGlowAlphaFinish = 0.f; + mGlowScaleYFinish = 0.f; + + mStartTime = AnimationUtils.currentAnimationTimeMillis(); + mDuration = RECEDE_TIME; + } + + /** + * Call when the effect absorbs an impact at the given velocity. + * Used when a fling reaches the scroll boundary. + * + * <p>When using a {@link android.widget.Scroller} or {@link android.widget.OverScroller}, + * the method <code>getCurrVelocity</code> will provide a reasonable approximation + * to use here.</p> + * + * @param velocity Velocity at impact in pixels per second. + */ + public void onAbsorb(int velocity) { + mState = STATE_ABSORB; + velocity = Math.min(Math.max(MIN_VELOCITY, Math.abs(velocity)), MAX_VELOCITY); + + mStartTime = AnimationUtils.currentAnimationTimeMillis(); + mDuration = 0.15f + (velocity * 0.02f); + + // The glow depends more on the velocity, and therefore starts out + // nearly invisible. + mGlowAlphaStart = 0.3f; + mGlowScaleYStart = Math.max(mGlowScaleY, 0.f); + + + // Growth for the size of the glow should be quadratic to properly + // respond + // to a user's scrolling speed. The faster the scrolling speed, the more + // intense the effect should be for both the size and the saturation. + mGlowScaleYFinish = Math.min(0.025f + (velocity * (velocity / 100) * 0.00015f) / 2, 1.f); + // Alpha should change for the glow as well as size. + mGlowAlphaFinish = Math.max( + mGlowAlphaStart, Math.min(velocity * VELOCITY_GLOW_FACTOR * .00001f, MAX_ALPHA)); + mTargetDisplacement = 0.5f; + } + + /** + * Set the color of this edge effect in argb. + * + * @param color Color in argb + */ + public void setColor(int color) { + mPaint.setColor(color); + } + + /** + * Return the color of this edge effect in argb. + * @return The color of this edge effect in argb + */ + public int getColor() { + return mPaint.getColor(); + } + + /** + * Draw into the provided canvas. Assumes that the canvas has been rotated + * accordingly and the size has been set. The effect will be drawn the full + * width of X=0 to X=width, beginning from Y=0 and extending to some factor < + * 1.f of height. + * + * @param canvas Canvas to draw into + * @return true if drawing should continue beyond this frame to continue the + * animation + */ + public boolean draw(Canvas canvas) { + update(); + + final float centerX = mBounds.centerX(); + final float centerY = mBounds.height() - mRadius; + + canvas.scale(1.f, Math.min(mGlowScaleY, 1.f) * mBaseGlowScale, centerX, 0); + + final float displacement = Math.max(0, Math.min(mDisplacement, 1.f)) - 0.5f; + float translateX = mBounds.width() * displacement / 2; + mPaint.setAlpha((int) (0xff * mGlowAlpha)); + canvas.drawCircle(centerX + translateX, centerY, mRadius, mPaint); + + boolean oneLastFrame = false; + if (mState == STATE_RECEDE && mGlowScaleY == 0) { + mState = STATE_IDLE; + oneLastFrame = true; + } + + return mState != STATE_IDLE || oneLastFrame; + } + + /** + * Return the maximum height that the edge effect will be drawn at given the original + * {@link #setSize(int, int) input size}. + * @return The maximum height of the edge effect + */ + public int getMaxHeight() { + return (int) (mBounds.height() * MAX_GLOW_SCALE + 0.5f); + } + + private void update() { + final long time = AnimationUtils.currentAnimationTimeMillis(); + final float t = Math.min((time - mStartTime) / mDuration, 1.f); + + final float interp = mInterpolator.getInterpolation(t); + + mGlowAlpha = mGlowAlphaStart + (mGlowAlphaFinish - mGlowAlphaStart) * interp; + mGlowScaleY = mGlowScaleYStart + (mGlowScaleYFinish - mGlowScaleYStart) * interp; + mDisplacement = (mDisplacement + mTargetDisplacement) / 2; + + if (t >= 1.f - EPSILON) { + switch (mState) { + case STATE_ABSORB: + mState = STATE_RECEDE; + mStartTime = AnimationUtils.currentAnimationTimeMillis(); + mDuration = RECEDE_TIME; + + mGlowAlphaStart = mGlowAlpha; + mGlowScaleYStart = mGlowScaleY; + + // After absorb, the glow should fade to nothing. + mGlowAlphaFinish = 0.f; + mGlowScaleYFinish = 0.f; + break; + case STATE_PULL: + mState = STATE_PULL_DECAY; + mStartTime = AnimationUtils.currentAnimationTimeMillis(); + mDuration = PULL_DECAY_TIME; + + mGlowAlphaStart = mGlowAlpha; + mGlowScaleYStart = mGlowScaleY; + + // After pull, the glow should fade to nothing. + mGlowAlphaFinish = 0.f; + mGlowScaleYFinish = 0.f; + break; + case STATE_PULL_DECAY: + mState = STATE_RECEDE; + break; + case STATE_RECEDE: + mState = STATE_IDLE; + break; + } + } + } +} |