src/com/android/launcher3/Utilities.java

/*
 * Copyright (C) 2008 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;

import java.util.Random;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BlurMaskFilter;
import android.graphics.Canvas;
import android.graphics.ColorMatrix;
import android.graphics.ColorMatrixColorFilter;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PaintFlagsDrawFilter;
import android.graphics.PorterDuff;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.PaintDrawable;
import android.util.DisplayMetrics;
import android.view.View;
import android.view.ViewGroup;

import java.util.ArrayList;

import com.android.launcher3.R;

/**
 * Various utilities shared amongst the Launcher's classes.
 */
final class Utilities {
    @SuppressWarnings("unused")
    private static final String TAG = "Launcher.Utilities";

    private static int sIconWidth = -1;
    private static int sIconHeight = -1;
    private static int sIconTextureWidth = -1;
    private static int sIconTextureHeight = -1;

    private static final Paint sBlurPaint = new Paint();
    private static final Paint sGlowColorPressedPaint = new Paint();
    private static final Paint sGlowColorFocusedPaint = new Paint();
    private static final Paint sDisabledPaint = new Paint();
    private static final Rect sOldBounds = new Rect();
    private static final Canvas sCanvas = new Canvas();

    static {
        sCanvas.setDrawFilter(new PaintFlagsDrawFilter(Paint.DITHER_FLAG,
                Paint.FILTER_BITMAP_FLAG));
    }
    static int sColors[] = { 0xffff0000, 0xff00ff00, 0xff0000ff };
    static int sColorIndex = 0;

    /**
     * Returns a bitmap suitable for the all apps view. Used to convert pre-ICS
     * icon bitmaps that are stored in the database (which were 74x74 pixels at hdpi size)
     * to the proper size (48dp)
     */
    static Bitmap createIconBitmap(Bitmap icon, Context context) {
        int textureWidth = sIconTextureWidth;
        int textureHeight = sIconTextureHeight;
        int sourceWidth = icon.getWidth();
        int sourceHeight = icon.getHeight();
        if (sourceWidth > textureWidth && sourceHeight > textureHeight) {
            // Icon is bigger than it should be; clip it (solves the GB->ICS migration case)
            return Bitmap.createBitmap(icon,
                    (sourceWidth - textureWidth) / 2,
                    (sourceHeight - textureHeight) / 2,
                    textureWidth, textureHeight);
        } else if (sourceWidth == textureWidth && sourceHeight == textureHeight) {
            // Icon is the right size, no need to change it
            return icon;
        } else {
            // Icon is too small, render to a larger bitmap
            final Resources resources = context.getResources();
            return createIconBitmap(new BitmapDrawable(resources, icon), context);
        }
    }

    /**
     * Returns a bitmap suitable for the all apps view.
     */
    static Bitmap createIconBitmap(Drawable icon, Context context) {
        synchronized (sCanvas) { // we share the statics :-(
            if (sIconWidth == -1) {
                initStatics(context);
            }

            int width = sIconWidth;
            int height = sIconHeight;

            if (icon instanceof PaintDrawable) {
                PaintDrawable painter = (PaintDrawable) icon;
                painter.setIntrinsicWidth(width);
                painter.setIntrinsicHeight(height);
            } else if (icon instanceof BitmapDrawable) {
                // Ensure the bitmap has a density.
                BitmapDrawable bitmapDrawable = (BitmapDrawable) icon;
                Bitmap bitmap = bitmapDrawable.getBitmap();
                if (bitmap.getDensity() == Bitmap.DENSITY_NONE) {
                    bitmapDrawable.setTargetDensity(context.getResources().getDisplayMetrics());
                }
            }
            int sourceWidth = icon.getIntrinsicWidth();
            int sourceHeight = icon.getIntrinsicHeight();
            if (sourceWidth > 0 && sourceHeight > 0) {
                // Scale the icon proportionally to the icon dimensions
                final float ratio = (float) sourceWidth / sourceHeight;
                if (sourceWidth > sourceHeight) {
                    height = (int) (width / ratio);
                } else if (sourceHeight > sourceWidth) {
                    width = (int) (height * ratio);
                }
            }

            // no intrinsic size --> use default size
            int textureWidth = sIconTextureWidth;
            int textureHeight = sIconTextureHeight;

            final Bitmap bitmap = Bitmap.createBitmap(textureWidth, textureHeight,
                    Bitmap.Config.ARGB_8888);
            final Canvas canvas = sCanvas;
            canvas.setBitmap(bitmap);

            final int left = (textureWidth-width) / 2;
            final int top = (textureHeight-height) / 2;

            @SuppressWarnings("all") // suppress dead code warning
            final boolean debug = false;
            if (debug) {
                // draw a big box for the icon for debugging
                canvas.drawColor(sColors[sColorIndex]);
                if (++sColorIndex >= sColors.length) sColorIndex = 0;
                Paint debugPaint = new Paint();
                debugPaint.setColor(0xffcccc00);
                canvas.drawRect(left, top, left+width, top+height, debugPaint);
            }

            sOldBounds.set(icon.getBounds());
            icon.setBounds(left, top, left+width, top+height);
            icon.draw(canvas);
            icon.setBounds(sOldBounds);
            canvas.setBitmap(null);

            return bitmap;
        }
    }

    /**
     * Returns a Bitmap representing the thumbnail of the specified Bitmap.
     *
     * @param bitmap The bitmap to get a thumbnail of.
     * @param context The application's context.
     *
     * @return A thumbnail for the specified bitmap or the bitmap itself if the
     *         thumbnail could not be created.
     */
    static Bitmap resampleIconBitmap(Bitmap bitmap, Context context) {
        synchronized (sCanvas) { // we share the statics :-(
            if (sIconWidth == -1) {
                initStatics(context);
            }

            if (bitmap.getWidth() == sIconWidth && bitmap.getHeight() == sIconHeight) {
                return bitmap;
            } else {
                final Resources resources = context.getResources();
                return createIconBitmap(new BitmapDrawable(resources, bitmap), context);
            }
        }
    }

    /**
     * Given a coordinate relative to the descendant, find the coordinate in a parent view's
     * coordinates.
     *
     * @param descendant The descendant to which the passed coordinate is relative.
     * @param root The root view to make the coordinates relative to.
     * @param coord The coordinate that we want mapped.
     * @param includeRootScroll Whether or not to account for the scroll of the descendant:
     *          sometimes this is relevant as in a child's coordinates within the descendant.
     * @return The factor by which this descendant is scaled relative to this DragLayer. Caution
     *         this scale factor is assumed to be equal in X and Y, and so if at any point this
     *         assumption fails, we will need to return a pair of scale factors.
     */
    public static float getDescendantCoordRelativeToParent(View descendant, View root,
                                                           int[] coord, boolean includeRootScroll) {
        ArrayList<View> ancestorChain = new ArrayList<View>();

        float[] pt = {coord[0], coord[1]};

        View v = descendant;
        while(v != root && v != null) {
            ancestorChain.add(v);
            v = (View) v.getParent();
        }
        ancestorChain.add(root);

        float scale = 1.0f;
        int count = ancestorChain.size();
        for (int i = 0; i < count; i++) {
            View v0 = ancestorChain.get(i);
            View v1 = i < count -1 ? ancestorChain.get(i + 1) : null;

            // For TextViews, scroll has a meaning which relates to the text position
            // which is very strange... ignore the scroll.
            if (v0 != descendant || includeRootScroll) {
                pt[0] -= v0.getScrollX();
                pt[1] -= v0.getScrollY();
            }

            v0.getMatrix().mapPoints(pt);
            pt[0] += v0.getLeft();
            pt[1] += v0.getTop();
            scale *= v0.getScaleX();
        }

        coord[0] = (int) Math.round(pt[0]);
        coord[1] = (int) Math.round(pt[1]);
        return scale;
    }

    /**
     * Inverse of {@link #getDescendantCoordRelativeToSelf(View, int[])}.
     */
    public static float mapCoordInSelfToDescendent(View descendant, View root,
                                                   int[] coord) {
        ArrayList<View> ancestorChain = new ArrayList<View>();

        float[] pt = {coord[0], coord[1]};

        View v = descendant;
        while(v != root) {
            ancestorChain.add(v);
            v = (View) v.getParent();
        }
        ancestorChain.add(root);

        float scale = 1.0f;
        Matrix inverse = new Matrix();
        int count = ancestorChain.size();
        for (int i = count - 1; i >= 0; i--) {
            View ancestor = ancestorChain.get(i);
            View next = i > 0 ? ancestorChain.get(i-1) : null;

            pt[0] += ancestor.getScrollX();
            pt[1] += ancestor.getScrollY();

            if (next != null) {
                pt[0] -= next.getLeft();
                pt[1] -= next.getTop();
                next.getMatrix().invert(inverse);
                inverse.mapPoints(pt);
                scale *= next.getScaleX();
            }
        }

        coord[0] = (int) Math.round(pt[0]);
        coord[1] = (int) Math.round(pt[1]);
        return scale;
    }

    private static void initStatics(Context context) {
        final Resources resources = context.getResources();
        final DisplayMetrics metrics = resources.getDisplayMetrics();
        final float density = metrics.density;

        sIconWidth = sIconHeight = (int) resources.getDimension(R.dimen.app_icon_size);
        sIconTextureWidth = sIconTextureHeight = sIconWidth;

        sBlurPaint.setMaskFilter(new BlurMaskFilter(5 * density, BlurMaskFilter.Blur.NORMAL));
        sGlowColorPressedPaint.setColor(0xffffc300);
        sGlowColorFocusedPaint.setColor(0xffff8e00);

        ColorMatrix cm = new ColorMatrix();
        cm.setSaturation(0.2f);
        sDisabledPaint.setColorFilter(new ColorMatrixColorFilter(cm));
        sDisabledPaint.setAlpha(0x88);
    }

    public static void setIconSize(int widthPx) {
        sIconWidth = sIconHeight = widthPx;
        sIconTextureWidth = sIconTextureHeight = widthPx;
    }
}