Upstream oodles of Chrome for Android code into Chromium.

chrome/android/java_staging/src/org/chromium/chrome/browser/compositor/layouts/phone/stack/StackTab.java

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.compositor.layouts.phone.stack;
+
+import android.content.Context;
+import android.content.res.Resources;
+
+import com.google.android.apps.chrome.R;
+
+import org.chromium.base.annotations.SuppressFBWarnings;
+import org.chromium.chrome.browser.compositor.layouts.ChromeAnimation;
+import org.chromium.chrome.browser.compositor.layouts.Layout.Orientation;
+import org.chromium.chrome.browser.compositor.layouts.components.LayoutTab;
+
+/**
+ * StackTab is used to keep track of a thumbnail's bitmap and position and to
+ * draw itself onto the GL canvas at the desired Y Offset.
+ * @VisibleForTesting
+ */
+@SuppressFBWarnings("MS_PKGPROTECT")
+public class StackTab implements ChromeAnimation.Animatable<StackTab.Property> {
+    /**
+     * Properties that can be animated by using a
+     * {@link org.chromium.chrome.browser.compositor.layouts.ChromeAnimation.Animatable}.
+     */
+    enum Property {
+        SCALE,
+        SCROLL_OFFSET,
+        ALPHA,
+        X_IN_STACK_INFLUENCE,
+        X_IN_STACK_OFFSET,
+        X_OUT_OF_STACK,
+        Y_IN_STACK_INFLUENCE,
+        Y_IN_STACK_OFFSET,
+        Y_OUT_OF_STACK,
+        DISCARD_AMOUNT
+    }
+
+    // Cached values from values/dimens.xml
+    public static float sStackedTabVisibleSize; // stacked_tab_visible_size
+    public static float sStackBufferWidth; // stack_buffer_width
+    public static float sStackBufferHeight; // stack_buffer_height
+
+    // Positioner selector
+    private float mXInStackInfluence = 1.0f;
+    private float mYInStackInfluence = 1.0f;
+
+    // In stack positioner
+    private float mScrollOffset = 0.0f;
+    private float mXInStackOffset = 0.0f;
+    private float mYInStackOffset = 0.0f;
+
+    // Out of stack positioner
+    private float mXOutOfStack = 0.0f;
+    private float mYOutOfStack = 0.0f;
+
+    // Values that get animated
+    private float mAlpha = 1.0f;
+    private float mScale = 1.0f;
+    private float mDiscardAmount = 0.0f; // This might alter position, rotation and alpha
+
+    // Discard states
+    private float mDiscardOriginX;
+    private float mDiscardOriginY;
+    private boolean mDiscardFromClick;
+
+    // The index of the tab in the stack
+    private int mIndex;
+
+    // True if the tab is currently being removed (while animating).
+    protected boolean mDying = false;
+
+    // The visibility sorting value is used to determine the importance of the tab for
+    // texture allocation. It is computed from the area and its position in the stack.
+    // Larger values will have more priority for acquiring texture. Negative values "often"
+    // means that the tab is not visible at all (but there are no guaranty and it's fine).
+    private float mCachedVisibleArea = 0; // Intermediate value
+    private float mCachedIndexDistance = 0; // Intermediate value
+    private float mCacheStackVisibility = 1.0f; // Intermediate value
+    private long mVisiblitySortingValue = 0; // Sorting value based on visible area.
+    private int mOrderSortingValue = 0; // Sorting value based on distance to selection.
+
+    private LayoutTab mLayoutTab;
+
+    /**
+     * @param tab The tab this instance is supposed to draw.
+     */
+    public StackTab(LayoutTab tab) {
+        mLayoutTab = tab;
+    }
+
+    /**
+     * @param index The new index in the stack layout.
+     */
+    public void setNewIndex(int index) {
+        mIndex = index;
+    }
+
+    /**
+     * @return The index in the stack layout.
+     */
+    public int getIndex() {
+        return mIndex;
+    }
+
+    /**
+     * @return The {@link LayoutTab} this instance is supposed to draw.
+     */
+    public LayoutTab getLayoutTab() {
+        return mLayoutTab;
+    }
+
+    /**
+     * Set the {@link LayoutTab} this instance is supposed to draw.
+     */
+    public void setLayoutTab(LayoutTab tab) {
+        mLayoutTab = tab;
+    }
+
+    /**
+     * @return The id of the tab, same as the id from the Tab in TabModel.
+     */
+    public int getId() {
+        return mLayoutTab.getId();
+    }
+
+    /**
+     * @param y The vertical translation to be applied after the placement in the stack.
+     */
+    public void setYInStackOffset(float y) {
+        mYInStackOffset = y;
+    }
+
+    /**
+     * @return The vertical translation applied after the placement in the stack.
+     */
+    public float getYInStackOffset() {
+        return mYInStackOffset;
+    }
+
+    /**
+     * @param x The horizontal translation to be applied after the placement in the stack.
+     */
+    public void setXInStackOffset(float x) {
+        mXInStackOffset = x;
+    }
+
+    /**
+     * @return The horizontal translation applied after the placement in the stack.
+     */
+    public float getXInStackOffset() {
+        return mXInStackOffset;
+    }
+
+    /**
+     * @param y The vertical absolute position when out of stack.
+     */
+    public void setYOutOfStack(float y) {
+        mYOutOfStack = y;
+    }
+
+    /**
+     * @return The vertical absolute position when out of stack.
+     */
+    public float getYOutOfStack() {
+        return mYOutOfStack;
+    }
+
+    /**
+     * @param x The horizontal absolute position when out of stack.
+     */
+    public void setXOutOfStack(float x) {
+        mXOutOfStack = x;
+    }
+
+    /**
+     * @return The horizontal absolute position when out of stack.
+     */
+    public float getXOutOfStack() {
+        return mXOutOfStack;
+    }
+
+    /**
+     * Set the transparency value for all of the tab (the contents,
+     * border, etc...).  For components that allow specifying
+     * their own alpha values, it will use the min of these two fields.
+     *
+     * @param f The transparency value for the tab.
+     */
+    public void setAlpha(float f) {
+        mAlpha = f;
+    }
+
+    /**
+     * @return The transparency value for all of the tab components.
+     */
+    public float getAlpha() {
+        return mAlpha;
+    }
+
+    /**
+     * @param xInStackInfluence The horizontal blend value between instack
+     *                          and out of stack pacement [0 .. 1].
+     */
+    public void setXInStackInfluence(float xInStackInfluence) {
+        mXInStackInfluence = xInStackInfluence;
+    }
+
+    /**
+     * @return The horizontal blend value between instack and out of stack pacement [0 .. 1].
+     */
+    public float getXInStackInfluence() {
+        return mXInStackInfluence;
+    }
+
+    /**
+     * @param yInStackInfluence The vertical blend value between instack
+     *                          and out of stack pacement [0 .. 1].
+     */
+    public void setYInStackInfluence(float yInStackInfluence) {
+        mYInStackInfluence = yInStackInfluence;
+    }
+
+    /**
+     * @return The verical blend value between instack and out of stack pacement [0 .. 1].
+     */
+    public float getYInStackInfluence() {
+        return mYInStackInfluence;
+    }
+
+    /**
+     * @param scale The scale to apply to the tab, compared to the parent.
+     */
+    public void setScale(float scale) {
+        mScale = scale;
+    }
+
+    /**
+     * @return The scale to apply to the tab, compared to the parent.
+     */
+    public float getScale() {
+        return mScale;
+    }
+
+    /**
+     * @param offset The offset of the tab along the scrolling direction in scroll space.
+     */
+    public void setScrollOffset(float offset) {
+        mScrollOffset = offset;
+    }
+
+    /**
+     * @return The offset of the tab along the scrolling direction in scroll space.
+     */
+    public float getScrollOffset() {
+        return mScrollOffset;
+    }
+
+    /**
+     * @param amount The amount of discard displacement. 0 is no discard. Negative is discard
+     *               on the left. Positive is discard on the right.
+     */
+    public void setDiscardAmount(float amount) {
+        mDiscardAmount = amount;
+    }
+
+    /**
+     * @param deltaAmount The amount of delta discard to be added to the current discard amount.
+     */
+    public void addToDiscardAmount(float deltaAmount) {
+        mDiscardAmount += deltaAmount;
+    }
+
+    /**
+     * @return The amount of discard displacement. 0 is no discard. Negative is discard
+     *         on the left. Positive is discard on the right.
+     */
+    public float getDiscardAmount() {
+        return mDiscardAmount;
+    }
+
+    /**
+     * @param x The x coordinate in tab space of where the discard transforms should originate.
+     */
+    public void setDiscardOriginX(float x) {
+        mDiscardOriginX = x;
+    }
+
+    /**
+     * @param y The y coordinate in tab space of where the discard transforms should originate.
+     */
+    public void setDiscardOriginY(float y) {
+        mDiscardOriginY = y;
+    }
+
+    /**
+     * @return The x coordinate in tab space of where the discard transforms should originate.
+     */
+    public float getDiscardOriginX() {
+        return mDiscardOriginX;
+    }
+
+    /**
+     * @return The y coordinate in tab space of where the discard transforms should originate.
+     */
+    public float getDiscardOriginY() {
+        return mDiscardOriginY;
+    }
+
+    /**
+     * @param fromClick Whether or not this discard was from a click event.
+     */
+    public void setDiscardFromClick(boolean fromClick) {
+        mDiscardFromClick = fromClick;
+    }
+
+    /**
+     * @return Whether or not this discard was from a click event.
+     */
+    public boolean getDiscardFromClick() {
+        return mDiscardFromClick;
+    }
+
+    /**
+     * @param dying True if the Tab/ContentView will be destroyed, and we are still animating its
+     *              visible representation.
+     */
+    public void setDying(boolean dying) {
+        mDying = dying;
+    }
+
+    /**
+     * @return True if the Tab/ContentView is destroyed, but we are still animating its
+     *         visible representation.
+     */
+    public boolean isDying() {
+        return mDying;
+    }
+
+    /**
+     * The scroll space does not map linearly to the screen so it creates a nice slow down
+     * effect at the top of the screen while scrolling.
+     * Warps x so it matches y(x) = x - warpSize on the positive side and 0 on the negative side
+     * with a smooth transition between [0, 2 * warpSize].
+     * @see #screenToScroll(float, float)
+     *
+     * [-oo, 0] -> 0
+     * [0, 2 * warpSize] -> warpSize * ((x-warpSize) / 2 * warpSize + 0.5) ^ 2.
+     * [2 * warpSize, +oo] -> x
+     * @param x        The offset in scroll space.
+     * @param warpSize The size in scroll space of the slow down effect.
+     * @return         The offset on screen corresponding to the scroll space offset.
+     */
+    public static float scrollToScreen(float x, float warpSize) {
+        if (x <= 0) return 0;
+        if (x >= 2 * warpSize) return x - warpSize;
+        x = (x - warpSize) / (2.0f * warpSize) + 0.5f;
+        return x * x * warpSize;
+    }
+
+    /**
+     * Unwarps x so it matches the above warp function.
+     * @see #scrollToScreen(float, float)
+     *
+     * [-oo, 0] -> -warpSize
+     * [0, warpSize] -> 2 * warpSize * sqrt(x / warpSize).
+     * [warpSize, +oo] -> x + warpSize
+     * @param x        The screen space offset.
+     * @param warpSize The size in scroll space of the slow down effect.
+     * @return         The offset in scroll space corresponding to the offset on screen.
+     */
+    public static float screenToScroll(float x, float warpSize) {
+        if (x <= 0) return 0;
+        if (x >= warpSize) return x + warpSize;
+        return (float) Math.sqrt(x * warpSize) * 2;
+    }
+
+    /**
+     * @param orientation The orientation to choose to get the size.
+     * @return            The size of the content along the provided orientation.
+     */
+    public float getSizeInScrollDirection(int orientation) {
+        if (orientation == Orientation.PORTRAIT) {
+            return mLayoutTab.getScaledContentHeight();
+        } else {
+            return mLayoutTab.getScaledContentWidth();
+        }
+    }
+
+    /**
+     * Helper function that gather the static constants from values/dimens.xml.
+     * @param context The Android Context.
+     */
+    public static void resetDimensionConstants(Context context) {
+        Resources res = context.getResources();
+        final float pxToDp = 1.0f / res.getDisplayMetrics().density;
+        sStackedTabVisibleSize =
+                res.getDimensionPixelOffset(R.dimen.stacked_tab_visible_size) * pxToDp;
+        sStackBufferWidth = res.getDimensionPixelOffset(R.dimen.stack_buffer_width) * pxToDp;
+        sStackBufferHeight = res.getDimensionPixelOffset(R.dimen.stack_buffer_height) * pxToDp;
+    }
+
+    /**
+     * Reset the offset to factory default.
+     */
+    public void resetOffset() {
+        mXInStackInfluence = 1.0f;
+        mYInStackInfluence = 1.0f;
+        mScrollOffset = 0.0f;
+        mXInStackOffset = 0.0f;
+        mYInStackOffset = 0.0f;
+        mXOutOfStack = 0.0f;
+        mYOutOfStack = 0.0f;
+        mDiscardOriginX = 0.f;
+        mDiscardOriginY = 0.f;
+        mDiscardFromClick = false;
+    }
+
+    /**
+     * Updates the cached visible area value to be used to sort tabs by visibility.
+     * @param referenceIndex The index that has the highest priority.
+     */
+    public void updateVisiblityValue(int referenceIndex) {
+        mCachedVisibleArea = mLayoutTab.computeVisibleArea();
+        mCachedIndexDistance = Math.abs(mIndex - referenceIndex);
+        mOrderSortingValue = computeOrderSortingValue(mCachedIndexDistance, mCacheStackVisibility);
+        mVisiblitySortingValue = computeVisibilitySortingValue(
+                mCachedVisibleArea, mOrderSortingValue, mCacheStackVisibility);
+    }
+
+    /**
+     * Updates the cached visible area value to be used to sort tabs by visibility.
+     * @param stackVisibility   Multiplier that represents how much the stack fills the screen.
+     */
+    public void updateStackVisiblityValue(float stackVisibility) {
+        mCacheStackVisibility = stackVisibility;
+        mOrderSortingValue = computeOrderSortingValue(mCachedIndexDistance, mCacheStackVisibility);
+        mVisiblitySortingValue = computeVisibilitySortingValue(
+                mCachedVisibleArea, mOrderSortingValue, mCacheStackVisibility);
+    }
+
+    /**
+     * Computes the visibility sorting value based on the tab visible area, its distance to the
+     * central index and the overall visibility of the stack.
+     * The '-index' index factor need to be smaller for stack that have small visibility.
+     * Multiplying by a small stackVisibility makes it bigger (because it is negative), hence the
+     * division. To avoid dividing by 0 it need to be offset a bit. 0.1f is the 'a bit' part of
+     * the explanation.
+     */
+    private static long computeVisibilitySortingValue(
+            float area, float orderSortingValue, float stackVisibility) {
+        return (long) (area * stackVisibility - orderSortingValue);
+    }
+
+    /**
+     * @return The cached visible sorting value. Call updateCachedVisibleArea to update it.
+     */
+    public long getVisiblitySortingValue() {
+        return mVisiblitySortingValue;
+    }
+
+    /**
+     * Computes the ordering value only based on the distance of the tab to the center one.
+     * Low values have higher priority.
+     */
+    private static int computeOrderSortingValue(float indexDistance, float stackVisibility) {
+        return (int) ((indexDistance + 1) / (0.1f + 0.9f * stackVisibility));
+    }
+
+    /**
+     * @return The cached order sorting value. Used to sort based on the tab ordering rather than
+     *         visible area.
+     */
+    public int getOrderSortingValue() {
+        return mOrderSortingValue;
+    }
+
+    /**
+     * Callback for
+     * {@link org.chromium.chrome.browser.compositor.layouts.ChromeAnimation.Animatable}
+     *
+     * @param prop The property to set
+     * @param val The value to set it to
+     */
+    @Override
+    public void setProperty(Property prop, float val) {
+        switch (prop) {
+            case SCALE:
+                setScale(val);
+                break;
+            case SCROLL_OFFSET:
+                setScrollOffset(val);
+                break;
+            case ALPHA:
+                setAlpha(val);
+                break;
+            case X_IN_STACK_INFLUENCE:
+                setXInStackInfluence(val);
+                break;
+            case X_IN_STACK_OFFSET:
+                setXInStackOffset(val);
+                break;
+            case X_OUT_OF_STACK:
+                setXOutOfStack(val);
+                break;
+            case Y_IN_STACK_INFLUENCE:
+                setYInStackInfluence(val);
+                break;
+            case Y_IN_STACK_OFFSET:
+                setYInStackOffset(val);
+                break;
+            case Y_OUT_OF_STACK:
+                setYOutOfStack(val);
+                break;
+            case DISCARD_AMOUNT:
+                setDiscardAmount(val);
+                break;
+        }
+    }
+}