Android12 launcher3修改App图标白边问题

1.前言：

今天在Android12 Rom定制客制化系统应用时发现改变系统App图标的形状会出现一个问题，那就是图标被缩小了，没有显示完整，有一个白边，这在普通的App开发很少遇到，在Android系统Rom定制时才会出现此问题，记录一下修改过程.

2.修改前的截图如下：

2.1 圆角图标：

可以看到App的图标没有铺满，中间的图标有的是方形，有的是圆角，而且出现一个白边，显示不正常

2.2 圆形图标：

发现切换圆形图标后问题也有问题，更难看，而且有个图标还被放大了，白边很突兀，明细不正常.

3.修改BaseIconFactory：

核心修改方法如下：

    /**
     * Switches badging to left/right
     */
    public void setBadgeOnLeft(boolean badgeOnLeft) {
        mBadgeOnLeft = badgeOnLeft;
    }

    /**
     * Sets the background color used for wrapped adaptive icon
     */
    public void setWrapperBackgroundColor(int color) {
        mWrapperBackgroundColor = (Color.alpha(color) < 255) ? DEFAULT_WRAPPER_BACKGROUND : color;
    }

    /**
     * Disables the dominant color extraction for all icons loaded.
     */
    public void disableColorExtraction() {
        mDisableColorExtractor = true;
    }

    private Drawable normalizeAndWrapToAdaptiveIcon(@NonNull Drawable icon,
            boolean shrinkNonAdaptiveIcons, RectF outIconBounds, float[] outScale) {
        if (icon == null) {
            return null;
        }
        float scale = 1f;
/* 
        if (shrinkNonAdaptiveIcons && ATLEAST_OREO) {
            if (mWrapperIcon == null) {
                mWrapperIcon = mContext.getDrawable(R.drawable.adaptive_icon_drawable_wrapper)
                        .mutate();
            }
            AdaptiveIconDrawable dr = (AdaptiveIconDrawable) mWrapperIcon;
            dr.setBounds(0, 0, 1, 1);
            boolean[] outShape = new boolean[1];
            scale = getNormalizer().getScale(icon, outIconBounds, dr.getIconMask(), outShape);
            if (!(icon instanceof AdaptiveIconDrawable) && !outShape[0]) {
                FixedScaleDrawable fsd = ((FixedScaleDrawable) dr.getForeground());
                fsd.setDrawable(icon);
                fsd.setScale(scale);
                icon = dr;
                scale = getNormalizer().getScale(icon, outIconBounds, null, null);

                ((ColorDrawable) dr.getBackground()).setColor(mWrapperBackgroundColor);
            }
        } else {
            scale = getNormalizer().getScale(icon, outIconBounds, null, null);
        } */
        scale =getNormalizer().getScale(icon, outIconBounds, null, null);
        outScale[0] = scale;
      
        return icon;
    }

package com.android.launcher3.icons;

import static android.graphics.Paint.DITHER_FLAG;
import static android.graphics.Paint.FILTER_BITMAP_FLAG;

import static com.android.launcher3.icons.ShadowGenerator.BLUR_FACTOR;

import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PaintFlagsDrawFilter;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.drawable.AdaptiveIconDrawable;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.InsetDrawable;
import android.os.Build;
import android.os.Process;
import android.os.UserHandle;

import androidx.annotation.NonNull;

import com.android.launcher3.icons.BitmapInfo.Extender;

/**
 * This class will be moved to androidx library. There shouldn't be any dependency outside
 * this package.
 */
public class BaseIconFactory implements AutoCloseable {

    private static final String TAG = "BaseIconFactory";
    private static final int DEFAULT_WRAPPER_BACKGROUND = Color.WHITE;
    static final boolean ATLEAST_OREO = Build.VERSION.SDK_INT >= Build.VERSION_CODES.O;
    static final boolean ATLEAST_P = Build.VERSION.SDK_INT >= Build.VERSION_CODES.P;

    private static final float ICON_BADGE_SCALE = 0.444f;

    private final Rect mOldBounds = new Rect();
    protected final Context mContext;
    private final Canvas mCanvas;
    private final PackageManager mPm;
    private final ColorExtractor mColorExtractor;
    private boolean mDisableColorExtractor;
    private boolean mBadgeOnLeft = false;

    protected final int mFillResIconDpi;
    protected final int mIconBitmapSize;

    private IconNormalizer mNormalizer;
    private ShadowGenerator mShadowGenerator;
    private final boolean mShapeDetection;

    private Drawable mWrapperIcon;
    private int mWrapperBackgroundColor = DEFAULT_WRAPPER_BACKGROUND;
    private Bitmap mUserBadgeBitmap;

    private final Paint mTextPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG);
    private static final float PLACEHOLDER_TEXT_SIZE = 20f;
    private static int PLACEHOLDER_BACKGROUND_COLOR = Color.rgb(240, 240, 240);

    protected BaseIconFactory(Context context, int fillResIconDpi, int iconBitmapSize,
            boolean shapeDetection) {
        mContext = context.getApplicationContext();
        mShapeDetection = shapeDetection;
        mFillResIconDpi = fillResIconDpi;
        mIconBitmapSize = iconBitmapSize;

        mPm = mContext.getPackageManager();
        mColorExtractor = new ColorExtractor();

        mCanvas = new Canvas();
        mCanvas.setDrawFilter(new PaintFlagsDrawFilter(DITHER_FLAG, FILTER_BITMAP_FLAG));
        mTextPaint.setTextAlign(Paint.Align.CENTER);
        mTextPaint.setColor(PLACEHOLDER_BACKGROUND_COLOR);
        mTextPaint.setTextSize(context.getResources().getDisplayMetrics().density *
                PLACEHOLDER_TEXT_SIZE);
        clear();
    }

    public BaseIconFactory(Context context, int fillResIconDpi, int iconBitmapSize) {
        this(context, fillResIconDpi, iconBitmapSize, false);
    }

    protected void clear() {
        mWrapperBackgroundColor = DEFAULT_WRAPPER_BACKGROUND;
        mDisableColorExtractor = false;
        mBadgeOnLeft = false;
    }

    public ShadowGenerator getShadowGenerator() {
        if (mShadowGenerator == null) {
            mShadowGenerator = new ShadowGenerator(mIconBitmapSize);
        }
        return mShadowGenerator;
    }

    public IconNormalizer getNormalizer() {
        if (mNormalizer == null) {
            mNormalizer = new IconNormalizer(mContext, mIconBitmapSize, mShapeDetection);
        }
        return mNormalizer;
    }

    @SuppressWarnings("deprecation")
    public BitmapInfo createIconBitmap(Intent.ShortcutIconResource iconRes) {
        try {
            Resources resources = mPm.getResourcesForApplication(iconRes.packageName);
            if (resources != null) {
                final int id = resources.getIdentifier(iconRes.resourceName, null, null);
                // do not stamp old legacy shortcuts as the app may have already forgotten about it
                return createBadgedIconBitmap(
                        resources.getDrawableForDensity(id, mFillResIconDpi),
                        Process.myUserHandle() /* only available on primary user */,
                        false /* do not apply legacy treatment */);
            }
        } catch (Exception e) {
            // Icon not found.
        }
        return null;
    }

    /**
     * Create a placeholder icon using the passed in text.
     *
     * @param placeholder used for foreground element in the icon bitmap
     * @param color used for the foreground text color
     * @return
     */
    public BitmapInfo createIconBitmap(String placeholder, int color) {
        if (!ATLEAST_OREO) return null;

        Bitmap placeholderBitmap = Bitmap.createBitmap(mIconBitmapSize, mIconBitmapSize,
                Bitmap.Config.ARGB_8888);
        mTextPaint.setColor(color);
        Canvas canvas = new Canvas(placeholderBitmap);
        canvas.drawText(placeholder, mIconBitmapSize / 2, mIconBitmapSize * 5 / 8, mTextPaint);
        AdaptiveIconDrawable drawable = new AdaptiveIconDrawable(
                new ColorDrawable(PLACEHOLDER_BACKGROUND_COLOR),
                new BitmapDrawable(mContext.getResources(), placeholderBitmap));
        Bitmap icon = createIconBitmap(drawable, 1f);
        return BitmapInfo.of(icon, extractColor(icon));
    }

    public BitmapInfo createIconBitmap(Bitmap icon) {
        if (mIconBitmapSize != icon.getWidth() || mIconBitmapSize != icon.getHeight()) {
            icon = createIconBitmap(new BitmapDrawable(mContext.getResources(), icon), 1f);
        }

        return BitmapInfo.of(icon, extractColor(icon));
    }

    /**
     * Creates an icon from the bitmap cropped to the current device icon shape
     */
    public BitmapInfo createShapedIconBitmap(Bitmap icon, UserHandle user) {
        Drawable d = new FixedSizeBitmapDrawable(icon);
        if (ATLEAST_OREO) {
            float inset = AdaptiveIconDrawable.getExtraInsetFraction();
            inset = inset / (1 + 2 * inset);
            d = new AdaptiveIconDrawable(new ColorDrawable(Color.BLACK),
                    new InsetDrawable(d, inset, inset, inset, inset));
        }
        return createBadgedIconBitmap(d, user, true);
    }

    public BitmapInfo createBadgedIconBitmap(Drawable icon, UserHandle user,
            boolean shrinkNonAdaptiveIcons) {
        return createBadgedIconBitmap(icon, user, shrinkNonAdaptiveIcons, false, null);
    }

    public BitmapInfo createBadgedIconBitmap(Drawable icon, UserHandle user,
            int iconAppTargetSdk) {
        return createBadgedIconBitmap(icon, user, iconAppTargetSdk, false);
    }

    public BitmapInfo createBadgedIconBitmap(Drawable icon, UserHandle user,
            int iconAppTargetSdk, boolean isInstantApp) {
        return createBadgedIconBitmap(icon, user, iconAppTargetSdk, isInstantApp, null);
    }

    public BitmapInfo createBadgedIconBitmap(Drawable icon, UserHandle user,
            int iconAppTargetSdk, boolean isInstantApp, float[] scale) {
        boolean shrinkNonAdaptiveIcons = ATLEAST_P ||
                (ATLEAST_OREO && iconAppTargetSdk >= Build.VERSION_CODES.O);
        return createBadgedIconBitmap(icon, user, shrinkNonAdaptiveIcons, isInstantApp, scale);
    }

    public Bitmap createScaledBitmapWithoutShadow(Drawable icon, int iconAppTargetSdk) {
        boolean shrinkNonAdaptiveIcons = ATLEAST_P ||
                (ATLEAST_OREO && iconAppTargetSdk >= Build.VERSION_CODES.O);
        return  createScaledBitmapWithoutShadow(icon, shrinkNonAdaptiveIcons);
    }

    /**
     * Creates bitmap using the source drawable and various parameters.
     * The bitmap is visually normalized with other icons and has enough spacing to add shadow.
     *
     * @param icon                      source of the icon
     * @param user                      info can be used for a badge
     * @param shrinkNonAdaptiveIcons    {@code true} if non adaptive icons should be treated
     * @param isInstantApp              info can be used for a badge
     * @param scale                     returns the scale result from normalization
     * @return a bitmap suitable for disaplaying as an icon at various system UIs.
     */
    public BitmapInfo createBadgedIconBitmap(@NonNull Drawable icon, UserHandle user,
            boolean shrinkNonAdaptiveIcons, boolean isInstantApp, float[] scale) {
        if (scale == null) {
            scale = new float[1];
        }
        icon = normalizeAndWrapToAdaptiveIcon(icon, shrinkNonAdaptiveIcons, null, scale);
        Bitmap bitmap = createIconBitmap(icon, scale[0]);
        if (ATLEAST_OREO && icon instanceof AdaptiveIconDrawable) {
            mCanvas.setBitmap(bitmap);
            getShadowGenerator().recreateIcon(Bitmap.createBitmap(bitmap), mCanvas);
            mCanvas.setBitmap(null);
        }

        if (isInstantApp) {
            badgeWithDrawable(bitmap, mContext.getDrawable(R.drawable.ic_instant_app_badge));
        }
        if (user != null) {
            BitmapDrawable drawable = new FixedSizeBitmapDrawable(bitmap);
            Drawable badged = mPm.getUserBadgedIcon(drawable, user);
            if (badged instanceof BitmapDrawable) {
                bitmap = ((BitmapDrawable) badged).getBitmap();
            } else {
                bitmap = createIconBitmap(badged, 1f);
            }
        }
        int color = extractColor(bitmap);
        return icon instanceof BitmapInfo.Extender
                ? ((BitmapInfo.Extender) icon).getExtendedInfo(bitmap, color, this, scale[0], user)
                : BitmapInfo.of(bitmap, color);
    }

    public Bitmap getUserBadgeBitmap(UserHandle user) {
        if (mUserBadgeBitmap == null) {
            Bitmap bitmap = Bitmap.createBitmap(
                    mIconBitmapSize, mIconBitmapSize, Bitmap.Config.ARGB_8888);
            Drawable badgedDrawable = mPm.getUserBadgedIcon(
                    new FixedSizeBitmapDrawable(bitmap), user);
            if (badgedDrawable instanceof BitmapDrawable) {
                mUserBadgeBitmap = ((BitmapDrawable) badgedDrawable).getBitmap();
            } else {
                badgedDrawable.setBounds(0, 0, mIconBitmapSize, mIconBitmapSize);
                mUserBadgeBitmap = BitmapRenderer.createSoftwareBitmap(
                        mIconBitmapSize, mIconBitmapSize, badgedDrawable::draw);
            }
        }
        return mUserBadgeBitmap;
    }

    public Bitmap createScaledBitmapWithoutShadow(Drawable icon, boolean shrinkNonAdaptiveIcons) {
        RectF iconBounds = new RectF();
        float[] scale = new float[1];
        icon = normalizeAndWrapToAdaptiveIcon(icon, shrinkNonAdaptiveIcons, iconBounds, scale);
        return createIconBitmap(icon,
                Math.min(scale[0], ShadowGenerator.getScaleForBounds(iconBounds)));
    }

    /**
     * Switches badging to left/right
     */
    public void setBadgeOnLeft(boolean badgeOnLeft) {
        mBadgeOnLeft = badgeOnLeft;
    }

    /**
     * Sets the background color used for wrapped adaptive icon
     */
    public void setWrapperBackgroundColor(int color) {
        mWrapperBackgroundColor = (Color.alpha(color) < 255) ? DEFAULT_WRAPPER_BACKGROUND : color;
    }

    /**
     * Disables the dominant color extraction for all icons loaded.
     */
    public void disableColorExtraction() {
        mDisableColorExtractor = true;
    }

    private Drawable normalizeAndWrapToAdaptiveIcon(@NonNull Drawable icon,
            boolean shrinkNonAdaptiveIcons, RectF outIconBounds, float[] outScale) {
        if (icon == null) {
            return null;
        }
        float scale = 1f;
/* 
        if (shrinkNonAdaptiveIcons && ATLEAST_OREO) {
            if (mWrapperIcon == null) {
                mWrapperIcon = mContext.getDrawable(R.drawable.adaptive_icon_drawable_wrapper)
                        .mutate();
            }
            AdaptiveIconDrawable dr = (AdaptiveIconDrawable) mWrapperIcon;
            dr.setBounds(0, 0, 1, 1);
            boolean[] outShape = new boolean[1];
            scale = getNormalizer().getScale(icon, outIconBounds, dr.getIconMask(), outShape);
            if (!(icon instanceof AdaptiveIconDrawable) && !outShape[0]) {
                FixedScaleDrawable fsd = ((FixedScaleDrawable) dr.getForeground());
                fsd.setDrawable(icon);
                fsd.setScale(scale);
                icon = dr;
                scale = getNormalizer().getScale(icon, outIconBounds, null, null);

                ((ColorDrawable) dr.getBackground()).setColor(mWrapperBackgroundColor);
            }
        } else {
            scale = getNormalizer().getScale(icon, outIconBounds, null, null);
        } */
        scale =getNormalizer().getScale(icon, outIconBounds, null, null);
        outScale[0] = scale;
      
        return icon;
    }

    /**
     * Adds the {@param badge} on top of {@param target} using the badge dimensions.
     */
    public void badgeWithDrawable(Bitmap target, Drawable badge) {
        mCanvas.setBitmap(target);
        badgeWithDrawable(mCanvas, badge);
        mCanvas.setBitmap(null);
    }

    /**
     * Adds the {@param badge} on top of {@param target} using the badge dimensions.
     */
    public void badgeWithDrawable(Canvas target, Drawable badge) {
        int badgeSize = getBadgeSizeForIconSize(mIconBitmapSize);
        if (mBadgeOnLeft) {
            badge.setBounds(0, mIconBitmapSize - badgeSize, badgeSize, mIconBitmapSize);
        } else {
            badge.setBounds(mIconBitmapSize - badgeSize, mIconBitmapSize - badgeSize,
                    mIconBitmapSize, mIconBitmapSize);
        }
        badge.draw(target);
    }

    private Bitmap createIconBitmap(Drawable icon, float scale) {
        return createIconBitmap(icon, scale, mIconBitmapSize);
    }

    /**
     * @param icon drawable that should be flattened to a bitmap
     * @param scale the scale to apply before drawing {@param icon} on the canvas
     */
    public Bitmap createIconBitmap(@NonNull Drawable icon, float scale, int size) {
        Bitmap bitmap = Bitmap.createBitmap(size, size, Bitmap.Config.ARGB_8888);
        if (icon == null) {
            return bitmap;
        }
        mCanvas.setBitmap(bitmap);
        mOldBounds.set(icon.getBounds());

        if (ATLEAST_OREO && icon instanceof AdaptiveIconDrawable) {
            int offset = Math.max((int) Math.ceil(BLUR_FACTOR * size),
                    Math.round(size * (1 - scale) / 2 ));
            icon.setBounds(offset, offset, size - offset, size - offset);
            if (icon instanceof BitmapInfo.Extender) {
                ((Extender) icon).drawForPersistence(mCanvas);
            } else {
                icon.draw(mCanvas);
            }
        } else {
            if (icon instanceof BitmapDrawable) {
                BitmapDrawable bitmapDrawable = (BitmapDrawable) icon;
                Bitmap b = bitmapDrawable.getBitmap();
                if (bitmap != null && b.getDensity() == Bitmap.DENSITY_NONE) {
                    bitmapDrawable.setTargetDensity(mContext.getResources().getDisplayMetrics());
                }
            }
            int width = size;
            int height = size;

            int intrinsicWidth = icon.getIntrinsicWidth();
            int intrinsicHeight = icon.getIntrinsicHeight();
            if (intrinsicWidth > 0 && intrinsicHeight > 0) {
                // Scale the icon proportionally to the icon dimensions
                final float ratio = (float) intrinsicWidth / intrinsicHeight;
                if (intrinsicWidth > intrinsicHeight) {
                    height = (int) (width / ratio);
                } else if (intrinsicHeight > intrinsicWidth) {
                    width = (int) (height * ratio);
                }
            }
            final int left = (size - width) / 2;
            final int top = (size - height) / 2;
            icon.setBounds(left, top, left + width, top + height);
            mCanvas.save();
            mCanvas.scale(scale, scale, size / 2, size / 2);
            icon.draw(mCanvas);
            mCanvas.restore();

        }
        icon.setBounds(mOldBounds);
        mCanvas.setBitmap(null);
        return bitmap;
    }

    @Override
    public void close() {
        clear();
    }

    public BitmapInfo makeDefaultIcon(UserHandle user) {
        return createBadgedIconBitmap(getFullResDefaultActivityIcon(mFillResIconDpi),
                user, Build.VERSION.SDK_INT);
    }

    public static Drawable getFullResDefaultActivityIcon(int iconDpi) {
        return Resources.getSystem().getDrawableForDensity(
                Build.VERSION.SDK_INT >= Build.VERSION_CODES.O
                        ? android.R.drawable.sym_def_app_icon : android.R.mipmap.sym_def_app_icon,
                iconDpi);
    }

    /**
     * Badges the provided source with the badge info
     */
    public BitmapInfo badgeBitmap(Bitmap source, BitmapInfo badgeInfo) {
        Bitmap icon = BitmapRenderer.createHardwareBitmap(mIconBitmapSize, mIconBitmapSize, (c) -> {
            getShadowGenerator().recreateIcon(source, c);
            badgeWithDrawable(c, new FixedSizeBitmapDrawable(badgeInfo.icon));
        });
        return BitmapInfo.of(icon, badgeInfo.color);
    }

    private int extractColor(Bitmap bitmap) {
        return mDisableColorExtractor ? 0 : mColorExtractor.findDominantColorByHue(bitmap);
    }

    /**
     * Returns the correct badge size given an icon size
     */
    public static int getBadgeSizeForIconSize(int iconSize) {
        return (int) (ICON_BADGE_SCALE * iconSize);
    }

    /**
     * An extension of {@link BitmapDrawable} which returns the bitmap pixel size as intrinsic size.
     * This allows the badging to be done based on the action bitmap size rather than
     * the scaled bitmap size.
     */
    private static class FixedSizeBitmapDrawable extends BitmapDrawable {

        public FixedSizeBitmapDrawable(Bitmap bitmap) {
            super(null, bitmap);
        }

        @Override
        public int getIntrinsicHeight() {
            return getBitmap().getWidth();
        }

        @Override
        public int getIntrinsicWidth() {
            return getBitmap().getWidth();
        }
    }
}

4.修改FixedScaleDrawable :

核心修改如下：

    private static final float LEGACY_ICON_SCALE = 1.0f;

package com.android.launcher3.icons;

import android.content.res.Resources;
import android.content.res.Resources.Theme;
import android.graphics.Canvas;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.DrawableWrapper;
import android.util.AttributeSet;

import org.xmlpull.v1.XmlPullParser;

/**
 * Extension of {@link DrawableWrapper} which scales the child drawables by a fixed amount.
 */
public class FixedScaleDrawable extends DrawableWrapper {

    // TODO b/33553066 use the constant defined in MaskableIconDrawable
    private static final float LEGACY_ICON_SCALE = 1.0f;
    private float mScaleX, mScaleY;

    public FixedScaleDrawable() {
        super(new ColorDrawable());
        mScaleX = LEGACY_ICON_SCALE;
        mScaleY = LEGACY_ICON_SCALE;
    }

    @Override
    public void draw(Canvas canvas) {
        int saveCount = canvas.save();
        canvas.scale(mScaleX, mScaleY,
                getBounds().exactCenterX(), getBounds().exactCenterY());
        super.draw(canvas);
        canvas.restoreToCount(saveCount);
    }

    @Override
    public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs) { }

    @Override
    public void inflate(Resources r, XmlPullParser parser, AttributeSet attrs, Theme theme) { }

    public void setScale(float scale) {
        float h = getIntrinsicHeight();
        float w = getIntrinsicWidth();
        mScaleX = scale * LEGACY_ICON_SCALE;
        mScaleY = scale * LEGACY_ICON_SCALE;
        if (h > w && w > 0) {
            mScaleX *= w / h;
        } else if (w > h && h > 0) {
            mScaleY *= h / w;
        }
    }
}

5.修改IconNormalizer:

核心修改方法如下：

    private static float getScale(float hullArea, float boundingArea, float fullArea) {
        float hullByRect = hullArea / boundingArea;
        float scaleRequired;
        if (hullByRect < CIRCLE_AREA_BY_RECT) {
            scaleRequired = MAX_CIRCLE_AREA_FACTOR;
        } else {
            scaleRequired = MAX_SQUARE_AREA_FACTOR + LINEAR_SCALE_SLOPE * (1 - hullByRect);
        }

        float areaScale = hullArea / fullArea;
        // Use sqrt of the final ratio as the images is scaled across both width and height.
        float scale = (float) Math.sqrt(scaleRequired / areaScale);
        return scale < 1f ? scale : 1f;
    }

/*
 * 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.icons;

import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Region;
import android.graphics.drawable.AdaptiveIconDrawable;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.util.Log;

import java.nio.ByteBuffer;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

public class IconNormalizer {

    private static final String TAG = "IconNormalizer";
    private static final boolean DEBUG = false;
    // Ratio of icon visible area to full icon size for a square shaped icon
    private static final float MAX_SQUARE_AREA_FACTOR = 375.0f / 576;
    // Ratio of icon visible area to full icon size for a circular shaped icon
    private static final float MAX_CIRCLE_AREA_FACTOR = 380.0f / 576;

    private static final float CIRCLE_AREA_BY_RECT = (float) Math.PI / 4;

    // Slope used to calculate icon visible area to full icon size for any generic shaped icon.
    private static final float LINEAR_SCALE_SLOPE =
            (MAX_CIRCLE_AREA_FACTOR - MAX_SQUARE_AREA_FACTOR) / (1 - CIRCLE_AREA_BY_RECT);

    private static final int MIN_VISIBLE_ALPHA = 40;

    // Shape detection related constants
    private static final float BOUND_RATIO_MARGIN = .05f;
    private static final float PIXEL_DIFF_PERCENTAGE_THRESHOLD = 0.005f;
    private static final float SCALE_NOT_INITIALIZED = 0;

    // Ratio of the diameter of an normalized circular icon to the actual icon size.
    public static final float ICON_VISIBLE_AREA_FACTOR = 0.92f;

    private final int mMaxSize;
    private final Bitmap mBitmap;
    private final Canvas mCanvas;
    private final Paint mPaintMaskShape;
    private final Paint mPaintMaskShapeOutline;
    private final byte[] mPixels;

    private final RectF mAdaptiveIconBounds;
    private float mAdaptiveIconScale;

    private boolean mEnableShapeDetection;

    // for each y, stores the position of the leftmost x and the rightmost x
    private final float[] mLeftBorder;
    private final float[] mRightBorder;
    private final Rect mBounds;
    private final Path mShapePath;
    private final Matrix mMatrix;

    /** package private **/
    IconNormalizer(Context context, int iconBitmapSize, boolean shapeDetection) {
        // Use twice the icon size as maximum size to avoid scaling down twice.
        mMaxSize = iconBitmapSize * 2;
        mBitmap = Bitmap.createBitmap(mMaxSize, mMaxSize, Bitmap.Config.ALPHA_8);
        mCanvas = new Canvas(mBitmap);
        mPixels = new byte[mMaxSize * mMaxSize];
        mLeftBorder = new float[mMaxSize];
        mRightBorder = new float[mMaxSize];
        mBounds = new Rect();
        mAdaptiveIconBounds = new RectF();

        mPaintMaskShape = new Paint();
        mPaintMaskShape.setColor(Color.RED);
        mPaintMaskShape.setStyle(Paint.Style.FILL);
        mPaintMaskShape.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.XOR));

        mPaintMaskShapeOutline = new Paint();
        mPaintMaskShapeOutline.setStrokeWidth(
                2 * context.getResources().getDisplayMetrics().density);
        mPaintMaskShapeOutline.setStyle(Paint.Style.STROKE);
        mPaintMaskShapeOutline.setColor(Color.BLACK);
        mPaintMaskShapeOutline.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));

        mShapePath = new Path();
        mMatrix = new Matrix();
        mAdaptiveIconScale = SCALE_NOT_INITIALIZED;
        mEnableShapeDetection = shapeDetection;
    }

    private static float getScale(float hullArea, float boundingArea, float fullArea) {
        float hullByRect = hullArea / boundingArea;
        float scaleRequired;
        if (hullByRect < CIRCLE_AREA_BY_RECT) {
            scaleRequired = MAX_CIRCLE_AREA_FACTOR;
        } else {
            scaleRequired = MAX_SQUARE_AREA_FACTOR + LINEAR_SCALE_SLOPE * (1 - hullByRect);
        }

        float areaScale = hullArea / fullArea;
        // Use sqrt of the final ratio as the images is scaled across both width and height.
        float scale = (float) Math.sqrt(scaleRequired / areaScale);
        return scale < 1f ? scale : 1f;
    }

    /**
     * @param d Should be AdaptiveIconDrawable
     * @param size Canvas size to use
     */
    @TargetApi(Build.VERSION_CODES.O)
    public static float normalizeAdaptiveIcon(Drawable d, int size, @Nullable RectF outBounds) {
        Rect tmpBounds = new Rect(d.getBounds());
        d.setBounds(0, 0, size, size);

        Path path = ((AdaptiveIconDrawable) d).getIconMask();
        Region region = new Region();
        region.setPath(path, new Region(0, 0, size, size));

        Rect hullBounds = region.getBounds();
        int hullArea = GraphicsUtils.getArea(region);

        if (outBounds != null) {
            float sizeF = size;
            outBounds.set(
                    hullBounds.left / sizeF,
                    hullBounds.top / sizeF,
                    1 - (hullBounds.right / sizeF),
                    1 - (hullBounds.bottom / sizeF));
        }
        d.setBounds(tmpBounds);
        return getScale(hullArea, hullArea, size * size);
    }

    /**
     * Returns if the shape of the icon is same as the path.
     * For this method to work, the shape path bounds should be in [0,1]x[0,1] bounds.
     */
    private boolean isShape(Path maskPath) {
        // Condition1:
        // If width and height of the path not close to a square, then the icon shape is
        // not same as the mask shape.
        float iconRatio = ((float) mBounds.width()) / mBounds.height();
        if (Math.abs(iconRatio - 1) > BOUND_RATIO_MARGIN) {
            if (DEBUG) {
                Log.d(TAG, "Not same as mask shape because width != height. " + iconRatio);
            }
            return false;
        }

        // Condition 2:
        // Actual icon (white) and the fitted shape (e.g., circle)(red) XOR operation
        // should generate transparent image, if the actual icon is equivalent to the shape.

        // Fit the shape within the icon's bounding box
        mMatrix.reset();
        mMatrix.setScale(mBounds.width(), mBounds.height());
        mMatrix.postTranslate(mBounds.left, mBounds.top);
        maskPath.transform(mMatrix, mShapePath);

        // XOR operation
        mCanvas.drawPath(mShapePath, mPaintMaskShape);

        // DST_OUT operation around the mask path outline
        mCanvas.drawPath(mShapePath, mPaintMaskShapeOutline);

        // Check if the result is almost transparent
        return isTransparentBitmap();
    }

    /**
     * Used to determine if certain the bitmap is transparent.
     */
    private boolean isTransparentBitmap() {
        ByteBuffer buffer = ByteBuffer.wrap(mPixels);
        buffer.rewind();
        mBitmap.copyPixelsToBuffer(buffer);

        int y = mBounds.top;
        // buffer position
        int index = y * mMaxSize;
        // buffer shift after every row, width of buffer = mMaxSize
        int rowSizeDiff = mMaxSize - mBounds.right;

        int sum = 0;
        for (; y < mBounds.bottom; y++) {
            index += mBounds.left;
            for (int x = mBounds.left; x < mBounds.right; x++) {
                if ((mPixels[index] & 0xFF) > MIN_VISIBLE_ALPHA) {
                    sum++;
                }
                index++;
            }
            index += rowSizeDiff;
        }

        float percentageDiffPixels = ((float) sum) / (mBounds.width() * mBounds.height());
        return percentageDiffPixels < PIXEL_DIFF_PERCENTAGE_THRESHOLD;
    }

    /**
     * Returns the amount by which the {@param d} should be scaled (in both dimensions) so that it
     * matches the design guidelines for a launcher icon.
     *
     * We first calculate the convex hull of the visible portion of the icon.
     * This hull then compared with the bounding rectangle of the hull to find how closely it
     * resembles a circle and a square, by comparing the ratio of the areas. Note that this is not an
     * ideal solution but it gives satisfactory result without affecting the performance.
     *
     * This closeness is used to determine the ratio of hull area to the full icon size.
     * Refer {@link #MAX_CIRCLE_AREA_FACTOR} and {@link #MAX_SQUARE_AREA_FACTOR}
     *
     * @param outBounds optional rect to receive the fraction distance from each edge.
     */
    public synchronized float getScale(@NonNull Drawable d, @Nullable RectF outBounds,
            @Nullable Path path, @Nullable boolean[] outMaskShape) {
        if (BaseIconFactory.ATLEAST_OREO && d instanceof AdaptiveIconDrawable) {
            if (mAdaptiveIconScale == SCALE_NOT_INITIALIZED) {
                mAdaptiveIconScale = normalizeAdaptiveIcon(d, mMaxSize, mAdaptiveIconBounds);
            }
            if (outBounds != null) {
                outBounds.set(mAdaptiveIconBounds);
            }
            return mAdaptiveIconScale;
        }
        int width = d.getIntrinsicWidth();
        int height = d.getIntrinsicHeight();
        if (width <= 0 || height <= 0) {
            width = width <= 0 || width > mMaxSize ? mMaxSize : width;
            height = height <= 0 || height > mMaxSize ? mMaxSize : height;
        } else if (width > mMaxSize || height > mMaxSize) {
            int max = Math.max(width, height);
            width = mMaxSize * width / max;
            height = mMaxSize * height / max;
        }

        mBitmap.eraseColor(Color.TRANSPARENT);
        d.setBounds(0, 0, width, height);
        d.draw(mCanvas);

        ByteBuffer buffer = ByteBuffer.wrap(mPixels);
        buffer.rewind();
        mBitmap.copyPixelsToBuffer(buffer);

        // Overall bounds of the visible icon.
        int topY = -1;
        int bottomY = -1;
        int leftX = mMaxSize + 1;
        int rightX = -1;

        // Create border by going through all pixels one row at a time and for each row find
        // the first and the last non-transparent pixel. Set those values to mLeftBorder and
        // mRightBorder and use -1 if there are no visible pixel in the row.

        // buffer position
        int index = 0;
        // buffer shift after every row, width of buffer = mMaxSize
        int rowSizeDiff = mMaxSize - width;
        // first and last position for any row.
        int firstX, lastX;

        for (int y = 0; y < height; y++) {
            firstX = lastX = -1;
            for (int x = 0; x < width; x++) {
                if ((mPixels[index] & 0xFF) > MIN_VISIBLE_ALPHA) {
                    if (firstX == -1) {
                        firstX = x;
                    }
                    lastX = x;
                }
                index++;
            }
            index += rowSizeDiff;

            mLeftBorder[y] = firstX;
            mRightBorder[y] = lastX;

            // If there is at least one visible pixel, update the overall bounds.
            if (firstX != -1) {
                bottomY = y;
                if (topY == -1) {
                    topY = y;
                }

                leftX = Math.min(leftX, firstX);
                rightX = Math.max(rightX, lastX);
            }
        }

        if (topY == -1 || rightX == -1) {
            // No valid pixels found. Do not scale.
            return 1;
        }

        convertToConvexArray(mLeftBorder, 1, topY, bottomY);
        convertToConvexArray(mRightBorder, -1, topY, bottomY);

        // Area of the convex hull
        float area = 0;
        for (int y = 0; y < height; y++) {
            if (mLeftBorder[y] <= -1) {
                continue;
            }
            area += mRightBorder[y] - mLeftBorder[y] + 1;
        }

        mBounds.left = leftX;
        mBounds.right = rightX;

        mBounds.top = topY;
        mBounds.bottom = bottomY;

        if (outBounds != null) {
            outBounds.set(((float) mBounds.left) / width, ((float) mBounds.top) / height,
                    1 - ((float) mBounds.right) / width,
                    1 - ((float) mBounds.bottom) / height);
        }
        if (outMaskShape != null && mEnableShapeDetection && outMaskShape.length > 0) {
            outMaskShape[0] = isShape(path);
        }
        // Area of the rectangle required to fit the convex hull
        float rectArea = (bottomY + 1 - topY) * (rightX + 1 - leftX);
        return getScale(area, rectArea, width * height);
    }

    /**
     * Modifies {@param xCoordinates} to represent a convex border. Fills in all missing values
     * (except on either ends) with appropriate values.
     * @param xCoordinates map of x coordinate per y.
     * @param direction 1 for left border and -1 for right border.
     * @param topY the first Y position (inclusive) with a valid value.
     * @param bottomY the last Y position (inclusive) with a valid value.
     */
    private static void convertToConvexArray(
            float[] xCoordinates, int direction, int topY, int bottomY) {
        int total = xCoordinates.length;
        // The tangent at each pixel.
        float[] angles = new float[total - 1];

        int first = topY; // First valid y coordinate
        int last = -1;    // Last valid y coordinate which didn't have a missing value

        float lastAngle = Float.MAX_VALUE;

        for (int i = topY + 1; i <= bottomY; i++) {
            if (xCoordinates[i] <= -1) {
                continue;
            }
            int start;

            if (lastAngle == Float.MAX_VALUE) {
                start = first;
            } else {
                float currentAngle = (xCoordinates[i] - xCoordinates[last]) / (i - last);
                start = last;
                // If this position creates a concave angle, keep moving up until we find a
                // position which creates a convex angle.
                if ((currentAngle - lastAngle) * direction < 0) {
                    while (start > first) {
                        start --;
                        currentAngle = (xCoordinates[i] - xCoordinates[start]) / (i - start);
                        if ((currentAngle - angles[start]) * direction >= 0) {
                            break;
                        }
                    }
                }
            }

            // Reset from last check
            lastAngle = (xCoordinates[i] - xCoordinates[start]) / (i - start);
            // Update all the points from start.
            for (int j = start; j < i; j++) {
                angles[j] = lastAngle;
                xCoordinates[j] = xCoordinates[start] + lastAngle * (j - start);
            }
            last = i;
        }
    }

    /**
     * @return The diameter of the normalized circle that fits inside of the square (size x size).
     */
    public static int getNormalizedCircleSize(int size) {
        float area = size * size * MAX_CIRCLE_AREA_FACTOR;
        return (int) Math.round(Math.sqrt((4 * area) / Math.PI));
    }
}