xref: /packages/apps/ContactsCommon/src/com/android/contacts/common/util/MaterialColorMapUtils.java

/*
 * Copyright (C) 2014 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.contacts.common.util;

import com.android.contacts.common.R;

import android.content.res.Resources;
import android.content.res.TypedArray;
import android.os.Trace;

public class MaterialColorMapUtils {

    private final TypedArray sPrimaryColors;
    private final TypedArray sSecondaryColors;

    public MaterialColorMapUtils(Resources resources) {
        sPrimaryColors = resources.obtainTypedArray(
                com.android.contacts.common.R.array.letter_tile_colors);
        sSecondaryColors = resources.obtainTypedArray(
                com.android.contacts.common.R.array.letter_tile_colors_dark);
    }

    public static class MaterialPalette {
        public MaterialPalette(int primaryColor, int secondaryColor) {
            mPrimaryColor = primaryColor;
            mSecondaryColor = secondaryColor;
        }
        public final int mPrimaryColor;
        public final int mSecondaryColor;
    }

    /**
     * Return primary and secondary colors from the Material color palette that are similar to
     * {@param color}.
     */
    public MaterialPalette calculatePrimaryAndSecondaryColor(int color) {
        Trace.beginSection("calculatePrimaryAndSecondaryColor");

        final float colorHue = hue(color);
        float minimumDistance = Float.MAX_VALUE;
        int indexBestMatch = 0;
        for (int i = 0; i < sPrimaryColors.length(); i++) {
            final int primaryColor = sPrimaryColors.getColor(i, 0);
            final float comparedHue = hue(primaryColor);
            // No need to be perceptually accurate when calculating color distances since
            // we are only mapping to 15 colors. Being slightly inaccurate isn't going to change
            // the mapping very often.
            final float distance = Math.abs(comparedHue - colorHue);
            if (distance < minimumDistance) {
                minimumDistance = distance;
                indexBestMatch = i;
            }
        }

        Trace.endSection();
        return new MaterialPalette(sPrimaryColors.getColor(indexBestMatch, 0),
                sSecondaryColors.getColor(indexBestMatch, 0));
    }

    public static MaterialPalette getDefaultPrimaryAndSecondaryColors(Resources resources) {
        final int primaryColor = resources.getColor(
                R.color.quickcontact_default_photo_tint_color);
        final int secondaryColor = resources.getColor(
                R.color.quickcontact_default_photo_tint_color_dark);
        return new MaterialPalette(primaryColor, secondaryColor);
    }

    /**
     * Returns the hue component of a color int.
     *
     * @return A value between 0.0f and 1.0f
     */
    public static float hue(int color) {
        int r = (color >> 16) & 0xFF;
        int g = (color >> 8) & 0xFF;
        int b = color & 0xFF;

        int V = Math.max(b, Math.max(r, g));
        int temp = Math.min(b, Math.min(r, g));

        float H;

        if (V == temp) {
            H = 0;
        } else {
            final float vtemp = V - temp;
            final float cr = (V - r) / vtemp;
            final float cg = (V - g) / vtemp;
            final float cb = (V - b) / vtemp;

            if (r == V) {
                H = cb - cg;
            } else if (g == V) {
                H = 2 + cr - cb;
            } else {
                H = 4 + cg - cr;
            }

            H /= 6.f;
            if (H < 0) {
                H++;
            }
        }

        return H;
    }
}