| /* |
| * Copyright (C) 2011 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.gallery3d.ui; |
| |
| import android.content.Context; |
| import android.graphics.Rect; |
| import android.graphics.RectF; |
| import android.util.FloatMath; |
| |
| import com.android.gallery3d.common.Utils; |
| import com.android.gallery3d.data.MediaItem; |
| import com.android.gallery3d.util.GalleryUtils; |
| |
| class PositionController { |
| public static final int IMAGE_AT_LEFT_EDGE = 1; |
| public static final int IMAGE_AT_RIGHT_EDGE = 2; |
| public static final int IMAGE_AT_TOP_EDGE = 4; |
| public static final int IMAGE_AT_BOTTOM_EDGE = 8; |
| |
| private long mAnimationStartTime = NO_ANIMATION; |
| private static final long NO_ANIMATION = -1; |
| private static final long LAST_ANIMATION = -2; |
| |
| private int mAnimationKind; |
| private float mAnimationDuration; |
| private final static int ANIM_KIND_SCROLL = 0; |
| private final static int ANIM_KIND_SCALE = 1; |
| private final static int ANIM_KIND_SNAPBACK = 2; |
| private final static int ANIM_KIND_SLIDE = 3; |
| private final static int ANIM_KIND_ZOOM = 4; |
| private final static int ANIM_KIND_FLING = 5; |
| |
| // Animation time in milliseconds. The order must match ANIM_KIND_* above. |
| private final static int ANIM_TIME[] = { |
| 0, // ANIM_KIND_SCROLL |
| 50, // ANIM_KIND_SCALE |
| 600, // ANIM_KIND_SNAPBACK |
| 400, // ANIM_KIND_SLIDE |
| 300, // ANIM_KIND_ZOOM |
| 0, // ANIM_KIND_FLING (the duration is calculated dynamically) |
| }; |
| |
| // We try to scale up the image to fill the screen. But in order not to |
| // scale too much for small icons, we limit the max up-scaling factor here. |
| private static final float SCALE_LIMIT = 4; |
| private static final int sHorizontalSlack = GalleryUtils.dpToPixel(12); |
| |
| private static final float SCALE_MIN_EXTRA = 0.6f; |
| private static final float SCALE_MAX_EXTRA = 1.4f; |
| |
| private PhotoView mViewer; |
| private EdgeView mEdgeView; |
| private int mImageW, mImageH; |
| private int mViewW, mViewH; |
| |
| // The X, Y are the coordinate on bitmap which shows on the center of |
| // the view. We always keep the mCurrent{X,Y,Scale} sync with the actual |
| // values used currently. |
| private int mCurrentX, mFromX, mToX; |
| private int mCurrentY, mFromY, mToY; |
| private float mCurrentScale, mFromScale, mToScale; |
| |
| // The focus point of the scaling gesture (in bitmap coordinates). |
| private int mFocusBitmapX; |
| private int mFocusBitmapY; |
| private boolean mInScale; |
| |
| // The minimum and maximum scale we allow. |
| private float mScaleMin, mScaleMax = SCALE_LIMIT; |
| private boolean mExtraScalingRange = false; |
| |
| // This is used by the fling animation |
| private FlingScroller mScroller; |
| |
| // The bound of the stable region, see the comments above |
| // calculateStableBound() for details. |
| private int mBoundLeft, mBoundRight, mBoundTop, mBoundBottom; |
| |
| // Assume the image size is the same as view size before we know the actual |
| // size of image. |
| private boolean mUseViewSize = true; |
| |
| private RectF mTempRect = new RectF(); |
| private float[] mTempPoints = new float[8]; |
| |
| public PositionController(PhotoView viewer, Context context, |
| EdgeView edgeView) { |
| mViewer = viewer; |
| mEdgeView = edgeView; |
| mScroller = new FlingScroller(); |
| } |
| |
| public void setImageSize(int width, int height) { |
| |
| // If no image available, use view size. |
| if (width == 0 || height == 0) { |
| mUseViewSize = true; |
| mImageW = mViewW; |
| mImageH = mViewH; |
| mCurrentX = mImageW / 2; |
| mCurrentY = mImageH / 2; |
| mCurrentScale = 1; |
| mScaleMin = 1; |
| mViewer.setPosition(mCurrentX, mCurrentY, mCurrentScale); |
| return; |
| } |
| |
| mUseViewSize = false; |
| |
| float ratio = Math.min( |
| (float) mImageW / width, (float) mImageH / height); |
| |
| // See the comment above translate() for details. |
| mCurrentX = translate(mCurrentX, mImageW, width, ratio); |
| mCurrentY = translate(mCurrentY, mImageH, height, ratio); |
| mCurrentScale = mCurrentScale * ratio; |
| |
| mFromX = translate(mFromX, mImageW, width, ratio); |
| mFromY = translate(mFromY, mImageH, height, ratio); |
| mFromScale = mFromScale * ratio; |
| |
| mToX = translate(mToX, mImageW, width, ratio); |
| mToY = translate(mToY, mImageH, height, ratio); |
| mToScale = mToScale * ratio; |
| |
| mFocusBitmapX = translate(mFocusBitmapX, mImageW, width, ratio); |
| mFocusBitmapY = translate(mFocusBitmapY, mImageH, height, ratio); |
| |
| mImageW = width; |
| mImageH = height; |
| |
| mScaleMin = getMinimalScale(mImageW, mImageH); |
| |
| // Start animation from the saved rectangle if we have one. |
| Rect r = mViewer.retrieveOpenAnimationRect(); |
| if (r != null) { |
| // The animation starts from the specified rectangle; the image |
| // should be scaled and centered as the thumbnail shown in the |
| // rectangle to minimize janky opening animation. Note: The below |
| // implementation depends on how thumbnails are drawn and placed. |
| float size = MediaItem.getTargetSize( |
| MediaItem.TYPE_MICROTHUMBNAIL); |
| float scale = (size / Math.min(width, height)) * Math.min( |
| r.width() / size, r.height() / size); |
| |
| mCurrentX = Math.round((mViewW / 2f - r.centerX()) / scale) + mImageW / 2; |
| mCurrentY = Math.round((mViewH / 2f - r.centerY()) / scale) + mImageH / 2; |
| mCurrentScale = scale; |
| mViewer.openAnimationStarted(); |
| startSnapback(); |
| } else if (mAnimationStartTime == NO_ANIMATION) { |
| mCurrentScale = Utils.clamp(mCurrentScale, mScaleMin, mScaleMax); |
| } |
| mViewer.setPosition(mCurrentX, mCurrentY, mCurrentScale); |
| } |
| |
| public void zoomIn(float tapX, float tapY, float targetScale) { |
| if (targetScale > mScaleMax) targetScale = mScaleMax; |
| |
| // Convert the tap position to image coordinate |
| int tempX = Math.round((tapX - mViewW / 2) / mCurrentScale + mCurrentX); |
| int tempY = Math.round((tapY - mViewH / 2) / mCurrentScale + mCurrentY); |
| |
| calculateStableBound(targetScale); |
| int targetX = Utils.clamp(tempX, mBoundLeft, mBoundRight); |
| int targetY = Utils.clamp(tempY, mBoundTop, mBoundBottom); |
| |
| startAnimation(targetX, targetY, targetScale, ANIM_KIND_ZOOM); |
| } |
| |
| public void resetToFullView() { |
| startAnimation(mImageW / 2, mImageH / 2, mScaleMin, ANIM_KIND_ZOOM); |
| } |
| |
| public float getMinimalScale(int w, int h) { |
| return Math.min(SCALE_LIMIT, |
| Math.min((float) mViewW / w, (float) mViewH / h)); |
| } |
| |
| // Translate a coordinate on bitmap if the bitmap size changes. |
| // If the aspect ratio doesn't change, it's easy: |
| // |
| // r = w / w' (= h / h') |
| // x' = x / r |
| // y' = y / r |
| // |
| // However the aspect ratio may change. That happens when the user slides |
| // a image before it's loaded, we don't know the actual aspect ratio, so |
| // we will assume one. When we receive the actual bitmap size, we need to |
| // translate the coordinate from the old bitmap into the new bitmap. |
| // |
| // What we want to do is center the bitmap at the original position. |
| // |
| // ...+--+... |
| // . | | . |
| // . | | . |
| // ...+--+... |
| // |
| // First we scale down the new bitmap by a factor r = min(w/w', h/h'). |
| // Overlay it onto the original bitmap. Now (0, 0) of the old bitmap maps |
| // to (-(w-w'*r)/2 / r, -(h-h'*r)/2 / r) in the new bitmap. So (x, y) of |
| // the old bitmap maps to (x', y') in the new bitmap, where |
| // x' = (x-(w-w'*r)/2) / r = w'/2 + (x-w/2)/r |
| // y' = (y-(h-h'*r)/2) / r = h'/2 + (y-h/2)/r |
| private static int translate(int value, int size, int newSize, float ratio) { |
| return Math.round(newSize / 2f + (value - size / 2f) / ratio); |
| } |
| |
| public void setViewSize(int viewW, int viewH) { |
| boolean needLayout = mViewW == 0 || mViewH == 0; |
| |
| mViewW = viewW; |
| mViewH = viewH; |
| |
| if (mUseViewSize) { |
| mImageW = viewW; |
| mImageH = viewH; |
| mCurrentX = mImageW / 2; |
| mCurrentY = mImageH / 2; |
| mCurrentScale = 1; |
| mScaleMin = 1; |
| mViewer.setPosition(mCurrentX, mCurrentY, mCurrentScale); |
| return; |
| } |
| |
| // In most cases we want to keep the scaling factor intact when the |
| // view size changes. The cases we want to reset the scaling factor |
| // (to fit the view if possible) are (1) the scaling factor is too |
| // small for the new view size (2) the scaling factor has not been |
| // changed by the user. |
| boolean wasMinScale = (mCurrentScale == mScaleMin); |
| mScaleMin = getMinimalScale(mImageW, mImageH); |
| |
| if (needLayout || mCurrentScale < mScaleMin || wasMinScale) { |
| mCurrentX = mImageW / 2; |
| mCurrentY = mImageH / 2; |
| mCurrentScale = mScaleMin; |
| mViewer.setPosition(mCurrentX, mCurrentY, mCurrentScale); |
| } |
| } |
| |
| public void stopAnimation() { |
| mAnimationStartTime = NO_ANIMATION; |
| } |
| |
| public void skipAnimation() { |
| if (mAnimationStartTime == NO_ANIMATION) return; |
| mAnimationStartTime = NO_ANIMATION; |
| mCurrentX = mToX; |
| mCurrentY = mToY; |
| mCurrentScale = mToScale; |
| } |
| |
| public void beginScale(float focusX, float focusY) { |
| mInScale = true; |
| mFocusBitmapX = Math.round(mCurrentX + |
| (focusX - mViewW / 2f) / mCurrentScale); |
| mFocusBitmapY = Math.round(mCurrentY + |
| (focusY - mViewH / 2f) / mCurrentScale); |
| } |
| |
| // Returns true if the result scale is outside the stable range. |
| public boolean scaleBy(float s, float focusX, float focusY) { |
| |
| // We want to keep the focus point (on the bitmap) the same as when |
| // we begin the scale guesture, that is, |
| // |
| // mCurrentX' + (focusX - mViewW / 2f) / scale = mFocusBitmapX |
| // |
| s *= getTargetScale(); |
| int x = Math.round(mFocusBitmapX - (focusX - mViewW / 2f) / s); |
| int y = Math.round(mFocusBitmapY - (focusY - mViewH / 2f) / s); |
| |
| startAnimation(x, y, s, ANIM_KIND_SCALE); |
| return (s < mScaleMin || s > mScaleMax); |
| } |
| |
| public void endScale() { |
| mInScale = false; |
| startSnapbackIfNeeded(); |
| } |
| |
| public void setExtraScalingRange(boolean enabled) { |
| mExtraScalingRange = enabled; |
| if (!enabled) { |
| startSnapbackIfNeeded(); |
| } |
| } |
| |
| public float getCurrentScale() { |
| return mCurrentScale; |
| } |
| |
| public boolean isAtMinimalScale() { |
| return isAlmostEquals(mCurrentScale, mScaleMin); |
| } |
| |
| private static boolean isAlmostEquals(float a, float b) { |
| float diff = a - b; |
| return (diff < 0 ? -diff : diff) < 0.02f; |
| } |
| |
| public void up() { |
| startSnapback(); |
| } |
| |
| // |<--| (1/2) * mImageW |
| // +-------+-------+-------+ |
| // | | | | |
| // | | o | | |
| // | | | | |
| // +-------+-------+-------+ |
| // |<----------| (3/2) * mImageW |
| // Slide in the image from left or right. |
| // Precondition: mCurrentScale = 1 (mView{W|H} == mImage{W|H}). |
| // Sliding from left: mCurrentX = (1/2) * mImageW |
| // right: mCurrentX = (3/2) * mImageW |
| public void startSlideInAnimation(int direction) { |
| int fromX = (direction == PhotoView.TRANS_SLIDE_IN_LEFT) ? |
| mImageW / 2 : 3 * mImageW / 2; |
| mFromX = Math.round(fromX); |
| mFromY = Math.round(mImageH / 2f); |
| mCurrentX = mFromX; |
| mCurrentY = mFromY; |
| startAnimation( |
| mImageW / 2, mImageH / 2, mCurrentScale, ANIM_KIND_SLIDE); |
| } |
| |
| public void startHorizontalSlide(int distance) { |
| scrollBy(distance, 0, ANIM_KIND_SLIDE); |
| } |
| |
| private void scrollBy(float dx, float dy, int type) { |
| startAnimation(getTargetX() + Math.round(dx / mCurrentScale), |
| getTargetY() + Math.round(dy / mCurrentScale), |
| mCurrentScale, type); |
| } |
| |
| public void startScroll(float dx, float dy, boolean hasNext, |
| boolean hasPrev) { |
| int x = getTargetX() + Math.round(dx / mCurrentScale); |
| int y = getTargetY() + Math.round(dy / mCurrentScale); |
| |
| calculateStableBound(mCurrentScale); |
| |
| // Vertical direction: If we have space to move in the vertical |
| // direction, we show the edge effect when scrolling reaches the edge. |
| if (mBoundTop != mBoundBottom) { |
| if (y < mBoundTop) { |
| mEdgeView.onPull(mBoundTop - y, EdgeView.TOP); |
| } else if (y > mBoundBottom) { |
| mEdgeView.onPull(y - mBoundBottom, EdgeView.BOTTOM); |
| } |
| } |
| |
| y = Utils.clamp(y, mBoundTop, mBoundBottom); |
| |
| // Horizontal direction: we show the edge effect when the scrolling |
| // tries to go left of the first image or go right of the last image. |
| if (!hasPrev && x < mBoundLeft) { |
| int pixels = Math.round((mBoundLeft - x) * mCurrentScale); |
| mEdgeView.onPull(pixels, EdgeView.LEFT); |
| x = mBoundLeft; |
| } else if (!hasNext && x > mBoundRight) { |
| int pixels = Math.round((x - mBoundRight) * mCurrentScale); |
| mEdgeView.onPull(pixels, EdgeView.RIGHT); |
| x = mBoundRight; |
| } |
| |
| startAnimation(x, y, mCurrentScale, ANIM_KIND_SCROLL); |
| } |
| |
| public boolean fling(float velocityX, float velocityY) { |
| // We only want to do fling when the picture is zoomed-in. |
| if (viewWiderThanScaledImage(mCurrentScale) && |
| viewHigherThanScaledImage(mCurrentScale)) { |
| return false; |
| } |
| |
| // We only allow flinging in the directions where it won't go over the |
| // picture. |
| int edges = getImageAtEdges(); |
| if ((velocityX > 0 && (edges & IMAGE_AT_LEFT_EDGE) != 0) || |
| (velocityX < 0 && (edges & IMAGE_AT_RIGHT_EDGE) != 0)) { |
| velocityX = 0; |
| } |
| if ((velocityY > 0 && (edges & IMAGE_AT_TOP_EDGE) != 0) || |
| (velocityY < 0 && (edges & IMAGE_AT_BOTTOM_EDGE) != 0)) { |
| velocityY = 0; |
| } |
| if (isAlmostEquals(velocityX, 0) && isAlmostEquals(velocityY, 0)) { |
| return false; |
| } |
| |
| mScroller.fling(mCurrentX, mCurrentY, |
| Math.round(-velocityX / mCurrentScale), |
| Math.round(-velocityY / mCurrentScale), |
| mBoundLeft, mBoundRight, mBoundTop, mBoundBottom); |
| int targetX = mScroller.getFinalX(); |
| int targetY = mScroller.getFinalY(); |
| mAnimationDuration = mScroller.getDuration(); |
| startAnimation(targetX, targetY, mCurrentScale, ANIM_KIND_FLING); |
| return true; |
| } |
| |
| private void startAnimation( |
| int targetX, int targetY, float scale, int kind) { |
| mAnimationKind = kind; |
| if (targetX == mCurrentX && targetY == mCurrentY |
| && scale == mCurrentScale) { |
| onAnimationComplete(); |
| return; |
| } |
| |
| mFromX = mCurrentX; |
| mFromY = mCurrentY; |
| mFromScale = mCurrentScale; |
| |
| mToX = targetX; |
| mToY = targetY; |
| mToScale = Utils.clamp(scale, SCALE_MIN_EXTRA * mScaleMin, |
| SCALE_MAX_EXTRA * mScaleMax); |
| |
| // If the scaled height is smaller than the view height, |
| // force it to be in the center. |
| // (We do for height only, not width, because the user may |
| // want to scroll to the previous/next image.) |
| if (!mInScale && viewHigherThanScaledImage(mToScale)) { |
| mToY = mImageH / 2; |
| } |
| |
| mAnimationStartTime = AnimationTime.get(); |
| if (mAnimationKind != ANIM_KIND_FLING) { |
| mAnimationDuration = ANIM_TIME[mAnimationKind]; |
| } |
| advanceAnimation(); |
| } |
| |
| public void advanceAnimation() { |
| if (mAnimationStartTime == NO_ANIMATION) { |
| return; |
| } else if (mAnimationStartTime == LAST_ANIMATION) { |
| onAnimationComplete(); |
| return; |
| } |
| |
| long now = AnimationTime.get(); |
| float progress; |
| if (mAnimationDuration == 0) { |
| progress = 1; |
| } else { |
| progress = (now - mAnimationStartTime) / mAnimationDuration; |
| } |
| |
| if (progress >= 1) { |
| progress = 1; |
| mCurrentX = mToX; |
| mCurrentY = mToY; |
| mCurrentScale = mToScale; |
| mAnimationStartTime = LAST_ANIMATION; |
| } else { |
| float f = 1 - progress; |
| switch (mAnimationKind) { |
| case ANIM_KIND_SCROLL: |
| case ANIM_KIND_FLING: |
| progress = 1 - f; // linear |
| break; |
| case ANIM_KIND_SCALE: |
| progress = 1 - f * f; // quadratic |
| break; |
| case ANIM_KIND_SNAPBACK: |
| case ANIM_KIND_ZOOM: |
| case ANIM_KIND_SLIDE: |
| progress = 1 - f * f * f * f * f; // x^5 |
| break; |
| } |
| if (mAnimationKind == ANIM_KIND_FLING) { |
| flingInterpolate(progress); |
| } else { |
| linearInterpolate(progress); |
| } |
| } |
| mViewer.setPosition(mCurrentX, mCurrentY, mCurrentScale); |
| mViewer.invalidate(); |
| } |
| |
| private void onAnimationComplete() { |
| mAnimationStartTime = NO_ANIMATION; |
| if (mViewer.isInTransition()) { |
| mViewer.notifyTransitionComplete(); |
| } else { |
| if (startSnapbackIfNeeded()) mViewer.invalidate(); |
| } |
| } |
| |
| private void flingInterpolate(float progress) { |
| mScroller.computeScrollOffset(progress); |
| int oldX = mCurrentX; |
| int oldY = mCurrentY; |
| mCurrentX = mScroller.getCurrX(); |
| mCurrentY = mScroller.getCurrY(); |
| |
| // Check if we hit the edges; show edge effects if we do. |
| if (oldX > mBoundLeft && mCurrentX == mBoundLeft) { |
| int v = Math.round(-mScroller.getCurrVelocityX() * mCurrentScale); |
| mEdgeView.onAbsorb(v, EdgeView.LEFT); |
| } else if (oldX < mBoundRight && mCurrentX == mBoundRight) { |
| int v = Math.round(mScroller.getCurrVelocityX() * mCurrentScale); |
| mEdgeView.onAbsorb(v, EdgeView.RIGHT); |
| } |
| |
| if (oldY > mBoundTop && mCurrentY == mBoundTop) { |
| int v = Math.round(-mScroller.getCurrVelocityY() * mCurrentScale); |
| mEdgeView.onAbsorb(v, EdgeView.TOP); |
| } else if (oldY < mBoundBottom && mCurrentY == mBoundBottom) { |
| int v = Math.round(mScroller.getCurrVelocityY() * mCurrentScale); |
| mEdgeView.onAbsorb(v, EdgeView.BOTTOM); |
| } |
| } |
| |
| // Interpolates mCurrent{X,Y,Scale} given the progress in [0, 1]. |
| private void linearInterpolate(float progress) { |
| // To linearly interpolate the position on view coordinates, we do the |
| // following steps: |
| // (1) convert a bitmap position (x, y) to view coordinates: |
| // from: (x - mFromX) * mFromScale + mViewW / 2 |
| // to: (x - mToX) * mToScale + mViewW / 2 |
| // (2) interpolate between the "from" and "to" coordinates: |
| // (x - mFromX) * mFromScale * (1 - p) + (x - mToX) * mToScale * p |
| // + mViewW / 2 |
| // should be equal to |
| // (x - mCurrentX) * mCurrentScale + mViewW / 2 |
| // (3) The x-related terms in the above equation can be removed because |
| // mFromScale * (1 - p) + ToScale * p = mCurrentScale |
| // (4) Solve for mCurrentX, we have mCurrentX = |
| // (mFromX * mFromScale * (1 - p) + mToX * mToScale * p) / mCurrentScale |
| float fromX = mFromX * mFromScale; |
| float toX = mToX * mToScale; |
| float currentX = fromX + progress * (toX - fromX); |
| |
| float fromY = mFromY * mFromScale; |
| float toY = mToY * mToScale; |
| float currentY = fromY + progress * (toY - fromY); |
| |
| mCurrentScale = mFromScale + progress * (mToScale - mFromScale); |
| mCurrentX = Math.round(currentX / mCurrentScale); |
| mCurrentY = Math.round(currentY / mCurrentScale); |
| } |
| |
| // Returns true if redraw is needed. |
| private boolean startSnapbackIfNeeded() { |
| if (mAnimationStartTime != NO_ANIMATION) return false; |
| if (mInScale) return false; |
| if (mAnimationKind == ANIM_KIND_SCROLL && mViewer.isDown()) { |
| return false; |
| } |
| return startSnapback(); |
| } |
| |
| private boolean startSnapback() { |
| boolean needAnimation = false; |
| float scale = mCurrentScale; |
| |
| float scaleMin = mExtraScalingRange ? |
| mScaleMin * SCALE_MIN_EXTRA : mScaleMin; |
| float scaleMax = mExtraScalingRange ? |
| mScaleMax * SCALE_MAX_EXTRA : mScaleMax; |
| |
| if (mCurrentScale < scaleMin || mCurrentScale > scaleMax) { |
| needAnimation = true; |
| scale = Utils.clamp(mCurrentScale, scaleMin, scaleMax); |
| } |
| |
| calculateStableBound(scale, sHorizontalSlack); |
| int x = Utils.clamp(mCurrentX, mBoundLeft, mBoundRight); |
| int y = Utils.clamp(mCurrentY, mBoundTop, mBoundBottom); |
| |
| if (mCurrentX != x || mCurrentY != y || mCurrentScale != scale) { |
| needAnimation = true; |
| } |
| |
| if (needAnimation) { |
| startAnimation(x, y, scale, ANIM_KIND_SNAPBACK); |
| } |
| |
| return needAnimation; |
| } |
| |
| // Calculates the stable region of mCurrent{X/Y}, where "stable" means |
| // |
| // (1) If the dimension of scaled image >= view dimension, we will not |
| // see black region outside the image (at that dimension). |
| // (2) If the dimension of scaled image < view dimension, we will center |
| // the scaled image. |
| // |
| // We might temporarily go out of this stable during user interaction, |
| // but will "snap back" after user stops interaction. |
| // |
| // The results are stored in mBound{Left/Right/Top/Bottom}. |
| // |
| // An extra parameter "horizontalSlack" (which has the value of 0 usually) |
| // is used to extend the stable region by some pixels on each side |
| // horizontally. |
| private void calculateStableBound(float scale) { |
| calculateStableBound(scale, 0f); |
| } |
| |
| private void calculateStableBound(float scale, float horizontalSlack) { |
| // The number of pixels between the center of the view |
| // and the edge when the edge is aligned. |
| mBoundLeft = (int) FloatMath.ceil((mViewW - horizontalSlack) / (2 * scale)); |
| mBoundRight = mImageW - mBoundLeft; |
| mBoundTop = (int) FloatMath.ceil(mViewH / (2 * scale)); |
| mBoundBottom = mImageH - mBoundTop; |
| |
| // If the scaled height is smaller than the view height, |
| // force it to be in the center. |
| if (viewHigherThanScaledImage(scale)) { |
| mBoundTop = mBoundBottom = mImageH / 2; |
| } |
| |
| // Same for width |
| if (viewWiderThanScaledImage(scale)) { |
| mBoundLeft = mBoundRight = mImageW / 2; |
| } |
| } |
| |
| private boolean viewHigherThanScaledImage(float scale) { |
| return FloatMath.floor(mImageH * scale) <= mViewH; |
| } |
| |
| private boolean viewWiderThanScaledImage(float scale) { |
| return FloatMath.floor(mImageW * scale) <= mViewW; |
| } |
| |
| private boolean useCurrentValueAsTarget() { |
| return mAnimationStartTime == NO_ANIMATION || |
| mAnimationKind == ANIM_KIND_SNAPBACK || |
| mAnimationKind == ANIM_KIND_FLING; |
| } |
| |
| private float getTargetScale() { |
| return useCurrentValueAsTarget() ? mCurrentScale : mToScale; |
| } |
| |
| private int getTargetX() { |
| return useCurrentValueAsTarget() ? mCurrentX : mToX; |
| } |
| |
| private int getTargetY() { |
| return useCurrentValueAsTarget() ? mCurrentY : mToY; |
| } |
| |
| public RectF getImageBounds() { |
| float points[] = mTempPoints; |
| |
| /* |
| * (p0,p1)----------(p2,p3) |
| * | | |
| * | | |
| * (p4,p5)----------(p6,p7) |
| */ |
| points[0] = points[4] = -mCurrentX; |
| points[1] = points[3] = -mCurrentY; |
| points[2] = points[6] = mImageW - mCurrentX; |
| points[5] = points[7] = mImageH - mCurrentY; |
| |
| RectF rect = mTempRect; |
| rect.set(Float.POSITIVE_INFINITY, Float.POSITIVE_INFINITY, |
| Float.NEGATIVE_INFINITY, Float.NEGATIVE_INFINITY); |
| |
| float scale = mCurrentScale; |
| float offsetX = mViewW / 2; |
| float offsetY = mViewH / 2; |
| for (int i = 0; i < 4; ++i) { |
| float x = points[i + i] * scale + offsetX; |
| float y = points[i + i + 1] * scale + offsetY; |
| if (x < rect.left) rect.left = x; |
| if (x > rect.right) rect.right = x; |
| if (y < rect.top) rect.top = y; |
| if (y > rect.bottom) rect.bottom = y; |
| } |
| return rect; |
| } |
| |
| public int getImageWidth() { |
| return mImageW; |
| } |
| |
| public int getImageHeight() { |
| return mImageH; |
| } |
| |
| public int getImageAtEdges() { |
| calculateStableBound(mCurrentScale); |
| int edges = 0; |
| if (mCurrentX <= mBoundLeft) { |
| edges |= IMAGE_AT_LEFT_EDGE; |
| } |
| if (mCurrentX >= mBoundRight) { |
| edges |= IMAGE_AT_RIGHT_EDGE; |
| } |
| if (mCurrentY <= mBoundTop) { |
| edges |= IMAGE_AT_TOP_EDGE; |
| } |
| if (mCurrentY >= mBoundBottom) { |
| edges |= IMAGE_AT_BOTTOM_EDGE; |
| } |
| return edges; |
| } |
| } |