Merge "Update light/dark detection." into tm-dev am: 4e6dfca5

import com.android.internal.graphics.palette.CelebiQuantizer;

import com.android.internal.graphics.palette.Palette;

import com.android.internal.graphics.palette.VariationalKMeansQuantizer;

import com.android.internal.util.ContrastColorUtil;

import java.io.FileOutputStream;

import java.lang.annotation.Retention;

    // using the area instead. This way our comparisons are aspect ratio independent.

    private static final int MAX_WALLPAPER_EXTRACTION_AREA = MAX_BITMAP_SIZE * MAX_BITMAP_SIZE;

    // When extracting the main colors, only consider colors

    // present in at least MIN_COLOR_OCCURRENCE of the image

    private static final float MIN_COLOR_OCCURRENCE = 0.05f;

    // Decides when dark theme is optimal for this wallpaper

    private static final float DARK_THEME_MEAN_LUMINANCE = 0.3f;

    // Minimum mean luminosity that an image needs to have to support dark text

    private static final float BRIGHT_IMAGE_MEAN_LUMINANCE = 0.7f;

    // We also check if the image has dark pixels in it,

    // to avoid bright images with some dark spots.

    private static final float DARK_PIXEL_CONTRAST = 5.5f;

    private static final float MAX_DARK_AREA = 0.05f;

    // Decides when dark theme is optimal for this wallpaper.

    // The midpoint of perceptual luminance, 50, is 18.42 in relative luminance.

    // ColorUtils.calculateLuminance returns relative luminance on a scale from 0 to 1.

    private static final float DARK_THEME_MEAN_LUMINANCE = 0.1842f;

    private final List<Color> mMainColors;

    private final Map<Integer, Integer> mAllColors;

        this(primaryColor, secondaryColor, tertiaryColor, 0);

        // Calculate dark theme support based on primary color.

        final float[] tmpHsl = new float[3];

        ColorUtils.colorToHSL(primaryColor.toArgb(), tmpHsl);

        final float luminance = tmpHsl[2];

        if (luminance < DARK_THEME_MEAN_LUMINANCE) {

            mColorHints |= HINT_SUPPORTS_DARK_THEME;

        }

        final double relativeLuminance = ColorUtils.calculateLuminance(primaryColor.toArgb());

        final boolean wallpaperIsDark = relativeLuminance < DARK_THEME_MEAN_LUMINANCE;

        mColorHints |= wallpaperIsDark ? HINT_SUPPORTS_DARK_THEME : HINT_SUPPORTS_DARK_TEXT;

    }

    /**

        dimAmount = MathUtils.saturate(dimAmount);

        int[] pixels = new int[source.getWidth() * source.getHeight()];

        double totalLuminance = 0;

        final int maxDarkPixels = (int) (pixels.length * MAX_DARK_AREA);

        int darkPixels = 0;

        source.getPixels(pixels, 0 /* offset */, source.getWidth(), 0 /* x */, 0 /* y */,

                source.getWidth(), source.getHeight());

        int dimmingLayerAlpha = (int) (255 * dimAmount);

        int blackTransparent = ColorUtils.setAlphaComponent(Color.BLACK, dimmingLayerAlpha);

        // This bitmap was already resized to fit the maximum allowed area.

        // Let's just loop through the pixels, no sweat!

        float[] tmpHsl = new float[3];

        // The median luminance in the wallpaper will be used to decide if it is light or dark.

        //

        // Calculating the luminances, adding them to a data structure, then selecting

        // the middle element would be expensive, the sort would be O(n), where n is the number

        // of pixels.

        //

        // Instead, we create an integer array with 101 elements initialized to zero.

        // Why 101? 0 through 100, inclusive, matching the range of luminance.

        // Then, for each pixel, the luminance is calculated, and the integer at the array index

        // equal to the rounded luminance is incremented.

        //

        // After processing the pixels, the median luminance is determined by iterating over the

        // array containing the count for each luminance. Starting from 0, we adding the count at

        // each index until pixels.length/2 is exceeded. When that occurs, it means the current

        // array index contains the pixel of median luminance, thus the current array index is the

        // median luminance.

        int[] luminanceCounts = new int[101];

        for (int i = 0; i < pixels.length; i++) {

            int pixelColor = pixels[i];

            ColorUtils.colorToHSL(pixelColor, tmpHsl);

            final int alpha = Color.alpha(pixelColor);

            // Apply composite colors where the foreground is a black layer with an alpha value of

            // the dim amount and the background is the wallpaper pixel color.

            int compositeColors = ColorUtils.compositeColors(blackTransparent, pixelColor);

            // Calculate the adjusted luminance of the dimmed wallpaper pixel color.

            double adjustedLuminance = ColorUtils.calculateLuminance(compositeColors);

            // Make sure we don't have a dark pixel mass that will

            // make text illegible.

            final boolean satisfiesTextContrast = ContrastColorUtil

                    .calculateContrast(pixelColor, Color.BLACK) > DARK_PIXEL_CONTRAST;

            if (!satisfiesTextContrast && alpha != 0) {

                darkPixels++;

                if (DEBUG_DARK_PIXELS) {

                    pixels[i] = Color.RED;

                }

            }

            totalLuminance += adjustedLuminance;

        }

            if (alpha == 0) {

                continue;

            }

            // If the wallpaper is dimmed, apply dimming before calculating luminance.

            int compositeColor = dimAmount <= 0 ? pixelColor :

                    ColorUtils.compositeColors(blackTransparent, pixelColor);

            // calculateLuminance will return relative luminance on a scale from 0 to 1. Intent

            // is normalize to 0 to 100, and that is done by defensively normalizing to

            // luminanceCounts.length, then flooring the result to defensively avoid any imprecision

            // in the result of calculateLuminance that could cause it to exceed 1 and thus the

            // array bounds.

            float relativeLuminance = (float) ColorUtils.calculateLuminance(compositeColor)

                    * luminanceCounts.length - 1;

            int intRelativeLuminance = (int) Math.floor(relativeLuminance);

            int clampedRelativeLuminance = (intRelativeLuminance < 0) ? 0 :

                    (intRelativeLuminance > luminanceCounts.length - 1) ? luminanceCounts.length - 1

                            : intRelativeLuminance;

            luminanceCounts[clampedRelativeLuminance] += 1;

        }

        int criticalRelativeLuminance = 0;

        int luminancesProcessed = 0;

        int criticalLuminanceIndex = (int) Math.floor(pixels.length * 0.5);

        for (int i = 0; i < 100; i++) {

            luminancesProcessed += luminanceCounts[i];

            if (luminancesProcessed > criticalLuminanceIndex) {

                criticalRelativeLuminance = i;

                break;

            }

        }

        // Wallpaper is dark if the median pixel is less than mid-gray.

        //

        // Relative luminance places mid-gray at 18.42, 19 is used since luminances were rounded to

        // ints to be stored in the array.

        //

        // Why not use perceptual luminance? It would require one more conversion step at each

        // pixel, or adding a function to convert relative luminance to perceptual luminance just

        // for this line.

        boolean wallpaperIsDark = criticalRelativeLuminance < 19;

        int hints = 0;

        double meanLuminance = totalLuminance / pixels.length;

        if (meanLuminance > BRIGHT_IMAGE_MEAN_LUMINANCE && darkPixels < maxDarkPixels) {

            hints |= HINT_SUPPORTS_DARK_TEXT;

        }

        if (meanLuminance < DARK_THEME_MEAN_LUMINANCE) {

            hints |= HINT_SUPPORTS_DARK_THEME;

        }

        hints |= wallpaperIsDark ? HINT_SUPPORTS_DARK_THEME : HINT_SUPPORTS_DARK_TEXT;

        if (DEBUG_DARK_PIXELS) {

            try (FileOutputStream out = new FileOutputStream("/data/pixels.png")) {

            } catch (Exception e) {

                e.printStackTrace();

            }

            Log.d("WallpaperColors", "l: " + meanLuminance + ", d: " + darkPixels +

                    " maxD: " + maxDarkPixels + " numPixels: " + pixels.length);

            Log.d("WallpaperColors", "median relative L: " + criticalRelativeLuminance

                    + ", numPixels: " + pixels.length);

        }

        return hints;