| /* |
| * 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.internal.util; |
| |
| import android.annotation.ColorInt; |
| import android.annotation.FloatRange; |
| import android.annotation.IntRange; |
| import android.annotation.NonNull; |
| import android.app.Notification; |
| import android.content.Context; |
| import android.content.res.ColorStateList; |
| import android.content.res.Resources; |
| import android.graphics.Bitmap; |
| import android.graphics.Color; |
| import android.graphics.drawable.AnimationDrawable; |
| import android.graphics.drawable.BitmapDrawable; |
| import android.graphics.drawable.Drawable; |
| import android.graphics.drawable.Icon; |
| import android.graphics.drawable.VectorDrawable; |
| import android.text.SpannableStringBuilder; |
| import android.text.Spanned; |
| import android.text.style.BackgroundColorSpan; |
| import android.text.style.CharacterStyle; |
| import android.text.style.ForegroundColorSpan; |
| import android.text.style.TextAppearanceSpan; |
| import android.util.Log; |
| import android.util.Pair; |
| |
| import java.util.Arrays; |
| import java.util.WeakHashMap; |
| |
| /** |
| * Helper class to process legacy (Holo) notifications to make them look like material notifications. |
| * |
| * @hide |
| */ |
| public class ContrastColorUtil { |
| |
| private static final String TAG = "ContrastColorUtil"; |
| private static final boolean DEBUG = false; |
| |
| private static final Object sLock = new Object(); |
| private static ContrastColorUtil sInstance; |
| |
| private final ImageUtils mImageUtils = new ImageUtils(); |
| private final WeakHashMap<Bitmap, Pair<Boolean, Integer>> mGrayscaleBitmapCache = |
| new WeakHashMap<Bitmap, Pair<Boolean, Integer>>(); |
| |
| private final int mGrayscaleIconMaxSize; // @dimen/notification_large_icon_width (64dp) |
| |
| public static ContrastColorUtil getInstance(Context context) { |
| synchronized (sLock) { |
| if (sInstance == null) { |
| sInstance = new ContrastColorUtil(context); |
| } |
| return sInstance; |
| } |
| } |
| |
| private ContrastColorUtil(Context context) { |
| mGrayscaleIconMaxSize = context.getResources().getDimensionPixelSize( |
| com.android.internal.R.dimen.notification_large_icon_width); |
| } |
| |
| /** |
| * Checks whether a Bitmap is a small grayscale icon. |
| * Grayscale here means "very close to a perfect gray"; icon means "no larger than 64dp". |
| * |
| * @param bitmap The bitmap to test. |
| * @return True if the bitmap is grayscale; false if it is color or too large to examine. |
| */ |
| public boolean isGrayscaleIcon(Bitmap bitmap) { |
| // quick test: reject large bitmaps |
| if (bitmap.getWidth() > mGrayscaleIconMaxSize |
| || bitmap.getHeight() > mGrayscaleIconMaxSize) { |
| return false; |
| } |
| |
| synchronized (sLock) { |
| Pair<Boolean, Integer> cached = mGrayscaleBitmapCache.get(bitmap); |
| if (cached != null) { |
| if (cached.second == bitmap.getGenerationId()) { |
| return cached.first; |
| } |
| } |
| } |
| boolean result; |
| int generationId; |
| synchronized (mImageUtils) { |
| result = mImageUtils.isGrayscale(bitmap); |
| |
| // generationId and the check whether the Bitmap is grayscale can't be read atomically |
| // here. However, since the thread is in the process of posting the notification, we can |
| // assume that it doesn't modify the bitmap while we are checking the pixels. |
| generationId = bitmap.getGenerationId(); |
| } |
| synchronized (sLock) { |
| mGrayscaleBitmapCache.put(bitmap, Pair.create(result, generationId)); |
| } |
| return result; |
| } |
| |
| /** |
| * Checks whether a Drawable is a small grayscale icon. |
| * Grayscale here means "very close to a perfect gray"; icon means "no larger than 64dp". |
| * |
| * @param d The drawable to test. |
| * @return True if the bitmap is grayscale; false if it is color or too large to examine. |
| */ |
| public boolean isGrayscaleIcon(Drawable d) { |
| if (d == null) { |
| return false; |
| } else if (d instanceof BitmapDrawable) { |
| BitmapDrawable bd = (BitmapDrawable) d; |
| return bd.getBitmap() != null && isGrayscaleIcon(bd.getBitmap()); |
| } else if (d instanceof AnimationDrawable) { |
| AnimationDrawable ad = (AnimationDrawable) d; |
| int count = ad.getNumberOfFrames(); |
| return count > 0 && isGrayscaleIcon(ad.getFrame(0)); |
| } else if (d instanceof VectorDrawable) { |
| // We just assume you're doing the right thing if using vectors |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| public boolean isGrayscaleIcon(Context context, Icon icon) { |
| if (icon == null) { |
| return false; |
| } |
| switch (icon.getType()) { |
| case Icon.TYPE_BITMAP: |
| return isGrayscaleIcon(icon.getBitmap()); |
| case Icon.TYPE_RESOURCE: |
| return isGrayscaleIcon(context, icon.getResId()); |
| default: |
| return false; |
| } |
| } |
| |
| /** |
| * Checks whether a drawable with a resoure id is a small grayscale icon. |
| * Grayscale here means "very close to a perfect gray"; icon means "no larger than 64dp". |
| * |
| * @param context The context to load the drawable from. |
| * @return True if the bitmap is grayscale; false if it is color or too large to examine. |
| */ |
| public boolean isGrayscaleIcon(Context context, int drawableResId) { |
| if (drawableResId != 0) { |
| try { |
| return isGrayscaleIcon(context.getDrawable(drawableResId)); |
| } catch (Resources.NotFoundException ex) { |
| Log.e(TAG, "Drawable not found: " + drawableResId); |
| return false; |
| } |
| } else { |
| return false; |
| } |
| } |
| |
| /** |
| * Inverts all the grayscale colors set by {@link android.text.style.TextAppearanceSpan}s on |
| * the text. |
| * |
| * @param charSequence The text to process. |
| * @return The color inverted text. |
| */ |
| public CharSequence invertCharSequenceColors(CharSequence charSequence) { |
| if (charSequence instanceof Spanned) { |
| Spanned ss = (Spanned) charSequence; |
| Object[] spans = ss.getSpans(0, ss.length(), Object.class); |
| SpannableStringBuilder builder = new SpannableStringBuilder(ss.toString()); |
| for (Object span : spans) { |
| Object resultSpan = span; |
| if (resultSpan instanceof CharacterStyle) { |
| resultSpan = ((CharacterStyle) span).getUnderlying(); |
| } |
| if (resultSpan instanceof TextAppearanceSpan) { |
| TextAppearanceSpan processedSpan = processTextAppearanceSpan( |
| (TextAppearanceSpan) span); |
| if (processedSpan != resultSpan) { |
| resultSpan = processedSpan; |
| } else { |
| // we need to still take the orgininal for wrapped spans |
| resultSpan = span; |
| } |
| } else if (resultSpan instanceof ForegroundColorSpan) { |
| ForegroundColorSpan originalSpan = (ForegroundColorSpan) resultSpan; |
| int foregroundColor = originalSpan.getForegroundColor(); |
| resultSpan = new ForegroundColorSpan(processColor(foregroundColor)); |
| } else { |
| resultSpan = span; |
| } |
| builder.setSpan(resultSpan, ss.getSpanStart(span), ss.getSpanEnd(span), |
| ss.getSpanFlags(span)); |
| } |
| return builder; |
| } |
| return charSequence; |
| } |
| |
| private TextAppearanceSpan processTextAppearanceSpan(TextAppearanceSpan span) { |
| ColorStateList colorStateList = span.getTextColor(); |
| if (colorStateList != null) { |
| int[] colors = colorStateList.getColors(); |
| boolean changed = false; |
| for (int i = 0; i < colors.length; i++) { |
| if (ImageUtils.isGrayscale(colors[i])) { |
| |
| // Allocate a new array so we don't change the colors in the old color state |
| // list. |
| if (!changed) { |
| colors = Arrays.copyOf(colors, colors.length); |
| } |
| colors[i] = processColor(colors[i]); |
| changed = true; |
| } |
| } |
| if (changed) { |
| return new TextAppearanceSpan( |
| span.getFamily(), span.getTextStyle(), span.getTextSize(), |
| new ColorStateList(colorStateList.getStates(), colors), |
| span.getLinkTextColor()); |
| } |
| } |
| return span; |
| } |
| |
| /** |
| * Clears all color spans of a text |
| * @param charSequence the input text |
| * @return the same text but without color spans |
| */ |
| public static CharSequence clearColorSpans(CharSequence charSequence) { |
| if (charSequence instanceof Spanned) { |
| Spanned ss = (Spanned) charSequence; |
| Object[] spans = ss.getSpans(0, ss.length(), Object.class); |
| SpannableStringBuilder builder = new SpannableStringBuilder(ss.toString()); |
| for (Object span : spans) { |
| Object resultSpan = span; |
| if (resultSpan instanceof CharacterStyle) { |
| resultSpan = ((CharacterStyle) span).getUnderlying(); |
| } |
| if (resultSpan instanceof TextAppearanceSpan) { |
| TextAppearanceSpan originalSpan = (TextAppearanceSpan) resultSpan; |
| if (originalSpan.getTextColor() != null) { |
| resultSpan = new TextAppearanceSpan( |
| originalSpan.getFamily(), |
| originalSpan.getTextStyle(), |
| originalSpan.getTextSize(), |
| null, |
| originalSpan.getLinkTextColor()); |
| } |
| } else if (resultSpan instanceof ForegroundColorSpan |
| || (resultSpan instanceof BackgroundColorSpan)) { |
| continue; |
| } else { |
| resultSpan = span; |
| } |
| builder.setSpan(resultSpan, ss.getSpanStart(span), ss.getSpanEnd(span), |
| ss.getSpanFlags(span)); |
| } |
| return builder; |
| } |
| return charSequence; |
| } |
| |
| private int processColor(int color) { |
| return Color.argb(Color.alpha(color), |
| 255 - Color.red(color), |
| 255 - Color.green(color), |
| 255 - Color.blue(color)); |
| } |
| |
| /** |
| * Finds a suitable color such that there's enough contrast. |
| * |
| * @param color the color to start searching from. |
| * @param other the color to ensure contrast against. Assumed to be lighter than {@param color} |
| * @param findFg if true, we assume {@param color} is a foreground, otherwise a background. |
| * @param minRatio the minimum contrast ratio required. |
| * @return a color with the same hue as {@param color}, potentially darkened to meet the |
| * contrast ratio. |
| */ |
| public static int findContrastColor(int color, int other, boolean findFg, double minRatio) { |
| int fg = findFg ? color : other; |
| int bg = findFg ? other : color; |
| if (ColorUtilsFromCompat.calculateContrast(fg, bg) >= minRatio) { |
| return color; |
| } |
| |
| double[] lab = new double[3]; |
| ColorUtilsFromCompat.colorToLAB(findFg ? fg : bg, lab); |
| |
| double low = 0, high = lab[0]; |
| final double a = lab[1], b = lab[2]; |
| for (int i = 0; i < 15 && high - low > 0.00001; i++) { |
| final double l = (low + high) / 2; |
| if (findFg) { |
| fg = ColorUtilsFromCompat.LABToColor(l, a, b); |
| } else { |
| bg = ColorUtilsFromCompat.LABToColor(l, a, b); |
| } |
| if (ColorUtilsFromCompat.calculateContrast(fg, bg) > minRatio) { |
| low = l; |
| } else { |
| high = l; |
| } |
| } |
| return ColorUtilsFromCompat.LABToColor(low, a, b); |
| } |
| |
| /** |
| * Finds a suitable alpha such that there's enough contrast. |
| * |
| * @param color the color to start searching from. |
| * @param backgroundColor the color to ensure contrast against. |
| * @param minRatio the minimum contrast ratio required. |
| * @return the same color as {@param color} with potentially modified alpha to meet contrast |
| */ |
| public static int findAlphaToMeetContrast(int color, int backgroundColor, double minRatio) { |
| int fg = color; |
| int bg = backgroundColor; |
| if (ColorUtilsFromCompat.calculateContrast(fg, bg) >= minRatio) { |
| return color; |
| } |
| int startAlpha = Color.alpha(color); |
| int r = Color.red(color); |
| int g = Color.green(color); |
| int b = Color.blue(color); |
| |
| int low = startAlpha, high = 255; |
| for (int i = 0; i < 15 && high - low > 0; i++) { |
| final int alpha = (low + high) / 2; |
| fg = Color.argb(alpha, r, g, b); |
| if (ColorUtilsFromCompat.calculateContrast(fg, bg) > minRatio) { |
| high = alpha; |
| } else { |
| low = alpha; |
| } |
| } |
| return Color.argb(high, r, g, b); |
| } |
| |
| /** |
| * Finds a suitable color such that there's enough contrast. |
| * |
| * @param color the color to start searching from. |
| * @param other the color to ensure contrast against. Assumed to be darker than {@param color} |
| * @param findFg if true, we assume {@param color} is a foreground, otherwise a background. |
| * @param minRatio the minimum contrast ratio required. |
| * @return a color with the same hue as {@param color}, potentially darkened to meet the |
| * contrast ratio. |
| */ |
| public static int findContrastColorAgainstDark(int color, int other, boolean findFg, |
| double minRatio) { |
| int fg = findFg ? color : other; |
| int bg = findFg ? other : color; |
| if (ColorUtilsFromCompat.calculateContrast(fg, bg) >= minRatio) { |
| return color; |
| } |
| |
| float[] hsl = new float[3]; |
| ColorUtilsFromCompat.colorToHSL(findFg ? fg : bg, hsl); |
| |
| float low = hsl[2], high = 1; |
| for (int i = 0; i < 15 && high - low > 0.00001; i++) { |
| final float l = (low + high) / 2; |
| hsl[2] = l; |
| if (findFg) { |
| fg = ColorUtilsFromCompat.HSLToColor(hsl); |
| } else { |
| bg = ColorUtilsFromCompat.HSLToColor(hsl); |
| } |
| if (ColorUtilsFromCompat.calculateContrast(fg, bg) > minRatio) { |
| high = l; |
| } else { |
| low = l; |
| } |
| } |
| return findFg ? fg : bg; |
| } |
| |
| public static int ensureTextContrastOnBlack(int color) { |
| return findContrastColorAgainstDark(color, Color.BLACK, true /* fg */, 12); |
| } |
| |
| /** |
| * Finds a large text color with sufficient contrast over bg that has the same or darker hue as |
| * the original color, depending on the value of {@code isBgDarker}. |
| * |
| * @param isBgDarker {@code true} if {@code bg} is darker than {@code color}. |
| */ |
| public static int ensureLargeTextContrast(int color, int bg, boolean isBgDarker) { |
| return isBgDarker |
| ? findContrastColorAgainstDark(color, bg, true, 3) |
| : findContrastColor(color, bg, true, 3); |
| } |
| |
| /** |
| * Finds a text color with sufficient contrast over bg that has the same or darker hue as the |
| * original color, depending on the value of {@code isBgDarker}. |
| * |
| * @param isBgDarker {@code true} if {@code bg} is darker than {@code color}. |
| */ |
| public static int ensureTextContrast(int color, int bg, boolean isBgDarker) { |
| return ensureContrast(color, bg, isBgDarker, 4.5); |
| } |
| |
| /** |
| * Finds a color with sufficient contrast over bg that has the same or darker hue as the |
| * original color, depending on the value of {@code isBgDarker}. |
| * |
| * @param color the color to start searching from |
| * @param bg the color to ensure contrast against |
| * @param isBgDarker {@code true} if {@code bg} is darker than {@code color} |
| * @param minRatio the minimum contrast ratio required |
| */ |
| public static int ensureContrast(int color, int bg, boolean isBgDarker, double minRatio) { |
| return isBgDarker |
| ? findContrastColorAgainstDark(color, bg, true, minRatio) |
| : findContrastColor(color, bg, true, minRatio); |
| } |
| |
| /** Finds a background color for a text view with given text color and hint text color, that |
| * has the same hue as the original color. |
| */ |
| public static int ensureTextBackgroundColor(int color, int textColor, int hintColor) { |
| color = findContrastColor(color, hintColor, false, 3.0); |
| return findContrastColor(color, textColor, false, 4.5); |
| } |
| |
| private static String contrastChange(int colorOld, int colorNew, int bg) { |
| return String.format("from %.2f:1 to %.2f:1", |
| ColorUtilsFromCompat.calculateContrast(colorOld, bg), |
| ColorUtilsFromCompat.calculateContrast(colorNew, bg)); |
| } |
| |
| /** |
| * Resolves {@param color} to an actual color if it is {@link Notification#COLOR_DEFAULT} |
| */ |
| public static int resolveColor(Context context, int color, boolean defaultBackgroundIsDark) { |
| if (color == Notification.COLOR_DEFAULT) { |
| int res = defaultBackgroundIsDark |
| ? com.android.internal.R.color.notification_default_color_dark |
| : com.android.internal.R.color.notification_default_color_light; |
| return context.getColor(res); |
| } |
| return color; |
| } |
| |
| /** |
| * Resolves a Notification's color such that it has enough contrast to be used as the |
| * color for the Notification's action and header text on a background that is lighter than |
| * {@code notificationColor}. |
| * |
| * @see {@link #resolveContrastColor(Context, int, boolean)} |
| */ |
| public static int resolveContrastColor(Context context, int notificationColor, |
| int backgroundColor) { |
| return ContrastColorUtil.resolveContrastColor(context, notificationColor, |
| backgroundColor, false /* isDark */); |
| } |
| |
| /** |
| * Resolves a Notification's color such that it has enough contrast to be used as the |
| * color for the Notification's action and header text. |
| * |
| * @param notificationColor the color of the notification or {@link Notification#COLOR_DEFAULT} |
| * @param backgroundColor the background color to ensure the contrast against. |
| * @param isDark whether or not the {@code notificationColor} will be placed on a background |
| * that is darker than the color itself |
| * @return a color of the same hue with enough contrast against the backgrounds. |
| */ |
| public static int resolveContrastColor(Context context, int notificationColor, |
| int backgroundColor, boolean isDark) { |
| final int resolvedColor = resolveColor(context, notificationColor, isDark); |
| |
| int color = resolvedColor; |
| color = ContrastColorUtil.ensureTextContrast(color, backgroundColor, isDark); |
| |
| if (color != resolvedColor) { |
| if (DEBUG){ |
| Log.w(TAG, String.format( |
| "Enhanced contrast of notification for %s" |
| + " and %s (over background) by changing #%s to %s", |
| context.getPackageName(), |
| ContrastColorUtil.contrastChange(resolvedColor, color, backgroundColor), |
| Integer.toHexString(resolvedColor), Integer.toHexString(color))); |
| } |
| } |
| return color; |
| } |
| |
| /** |
| * Change a color by a specified value |
| * @param baseColor the base color to lighten |
| * @param amount the amount to lighten the color from 0 to 100. This corresponds to the L |
| * increase in the LAB color space. A negative value will darken the color and |
| * a positive will lighten it. |
| * @return the changed color |
| */ |
| public static int changeColorLightness(int baseColor, int amount) { |
| final double[] result = ColorUtilsFromCompat.getTempDouble3Array(); |
| ColorUtilsFromCompat.colorToLAB(baseColor, result); |
| result[0] = Math.max(Math.min(100, result[0] + amount), 0); |
| return ColorUtilsFromCompat.LABToColor(result[0], result[1], result[2]); |
| } |
| |
| public static int resolvePrimaryColor(Context context, int backgroundColor, |
| boolean defaultBackgroundIsDark) { |
| boolean useDark = shouldUseDark(backgroundColor, defaultBackgroundIsDark); |
| if (useDark) { |
| return context.getColor( |
| com.android.internal.R.color.notification_primary_text_color_light); |
| } else { |
| return context.getColor( |
| com.android.internal.R.color.notification_primary_text_color_dark); |
| } |
| } |
| |
| public static int resolveSecondaryColor(Context context, int backgroundColor, |
| boolean defaultBackgroundIsDark) { |
| boolean useDark = shouldUseDark(backgroundColor, defaultBackgroundIsDark); |
| if (useDark) { |
| return context.getColor( |
| com.android.internal.R.color.notification_secondary_text_color_light); |
| } else { |
| return context.getColor( |
| com.android.internal.R.color.notification_secondary_text_color_dark); |
| } |
| } |
| |
| public static int resolveDefaultColor(Context context, int backgroundColor, |
| boolean defaultBackgroundIsDark) { |
| boolean useDark = shouldUseDark(backgroundColor, defaultBackgroundIsDark); |
| if (useDark) { |
| return context.getColor( |
| com.android.internal.R.color.notification_default_color_light); |
| } else { |
| return context.getColor( |
| com.android.internal.R.color.notification_default_color_dark); |
| } |
| } |
| |
| /** |
| * Get a color that stays in the same tint, but darkens or lightens it by a certain |
| * amount. |
| * This also looks at the lightness of the provided color and shifts it appropriately. |
| * |
| * @param color the base color to use |
| * @param amount the amount from 1 to 100 how much to modify the color |
| * @return the new color that was modified |
| */ |
| public static int getShiftedColor(int color, int amount) { |
| final double[] result = ColorUtilsFromCompat.getTempDouble3Array(); |
| ColorUtilsFromCompat.colorToLAB(color, result); |
| if (result[0] >= 4) { |
| result[0] = Math.max(0, result[0] - amount); |
| } else { |
| result[0] = Math.min(100, result[0] + amount); |
| } |
| return ColorUtilsFromCompat.LABToColor(result[0], result[1], result[2]); |
| } |
| |
| /** |
| * Blends the provided color with white to create a muted version. |
| * |
| * @param color the color to mute |
| * @param alpha the amount from 0 to 1 to set the alpha component of the white scrim |
| * @return the new color that was modified |
| */ |
| public static int getMutedColor(int color, float alpha) { |
| int whiteScrim = ColorUtilsFromCompat.setAlphaComponent( |
| Color.WHITE, (int) (255 * alpha)); |
| return compositeColors(whiteScrim, color); |
| } |
| |
| private static boolean shouldUseDark(int backgroundColor, boolean defaultBackgroundIsDark) { |
| if (backgroundColor == Notification.COLOR_DEFAULT) { |
| return !defaultBackgroundIsDark; |
| } |
| return ColorUtilsFromCompat.calculateLuminance(backgroundColor) > 0.5; |
| } |
| |
| public static double calculateLuminance(int backgroundColor) { |
| return ColorUtilsFromCompat.calculateLuminance(backgroundColor); |
| } |
| |
| |
| public static double calculateContrast(int foregroundColor, int backgroundColor) { |
| return ColorUtilsFromCompat.calculateContrast(foregroundColor, backgroundColor); |
| } |
| |
| public static boolean satisfiesTextContrast(int backgroundColor, int foregroundColor) { |
| return ContrastColorUtil.calculateContrast(foregroundColor, backgroundColor) >= 4.5; |
| } |
| |
| /** |
| * Composite two potentially translucent colors over each other and returns the result. |
| */ |
| public static int compositeColors(int foreground, int background) { |
| return ColorUtilsFromCompat.compositeColors(foreground, background); |
| } |
| |
| public static boolean isColorLight(int backgroundColor) { |
| return calculateLuminance(backgroundColor) > 0.5f; |
| } |
| |
| /** |
| * Framework copy of functions needed from android.support.v4.graphics.ColorUtils. |
| */ |
| private static class ColorUtilsFromCompat { |
| private static final double XYZ_WHITE_REFERENCE_X = 95.047; |
| private static final double XYZ_WHITE_REFERENCE_Y = 100; |
| private static final double XYZ_WHITE_REFERENCE_Z = 108.883; |
| private static final double XYZ_EPSILON = 0.008856; |
| private static final double XYZ_KAPPA = 903.3; |
| |
| private static final int MIN_ALPHA_SEARCH_MAX_ITERATIONS = 10; |
| private static final int MIN_ALPHA_SEARCH_PRECISION = 1; |
| |
| private static final ThreadLocal<double[]> TEMP_ARRAY = new ThreadLocal<>(); |
| |
| private ColorUtilsFromCompat() {} |
| |
| /** |
| * Composite two potentially translucent colors over each other and returns the result. |
| */ |
| public static int compositeColors(@ColorInt int foreground, @ColorInt int background) { |
| int bgAlpha = Color.alpha(background); |
| int fgAlpha = Color.alpha(foreground); |
| int a = compositeAlpha(fgAlpha, bgAlpha); |
| |
| int r = compositeComponent(Color.red(foreground), fgAlpha, |
| Color.red(background), bgAlpha, a); |
| int g = compositeComponent(Color.green(foreground), fgAlpha, |
| Color.green(background), bgAlpha, a); |
| int b = compositeComponent(Color.blue(foreground), fgAlpha, |
| Color.blue(background), bgAlpha, a); |
| |
| return Color.argb(a, r, g, b); |
| } |
| |
| private static int compositeAlpha(int foregroundAlpha, int backgroundAlpha) { |
| return 0xFF - (((0xFF - backgroundAlpha) * (0xFF - foregroundAlpha)) / 0xFF); |
| } |
| |
| private static int compositeComponent(int fgC, int fgA, int bgC, int bgA, int a) { |
| if (a == 0) return 0; |
| return ((0xFF * fgC * fgA) + (bgC * bgA * (0xFF - fgA))) / (a * 0xFF); |
| } |
| |
| /** |
| * Set the alpha component of {@code color} to be {@code alpha}. |
| */ |
| @ColorInt |
| public static int setAlphaComponent(@ColorInt int color, |
| @IntRange(from = 0x0, to = 0xFF) int alpha) { |
| if (alpha < 0 || alpha > 255) { |
| throw new IllegalArgumentException("alpha must be between 0 and 255."); |
| } |
| return (color & 0x00ffffff) | (alpha << 24); |
| } |
| |
| /** |
| * Returns the luminance of a color as a float between {@code 0.0} and {@code 1.0}. |
| * <p>Defined as the Y component in the XYZ representation of {@code color}.</p> |
| */ |
| @FloatRange(from = 0.0, to = 1.0) |
| public static double calculateLuminance(@ColorInt int color) { |
| final double[] result = getTempDouble3Array(); |
| colorToXYZ(color, result); |
| // Luminance is the Y component |
| return result[1] / 100; |
| } |
| |
| /** |
| * Returns the contrast ratio between {@code foreground} and {@code background}. |
| * {@code background} must be opaque. |
| * <p> |
| * Formula defined |
| * <a href="http://www.w3.org/TR/2008/REC-WCAG20-20081211/#contrast-ratiodef">here</a>. |
| */ |
| public static double calculateContrast(@ColorInt int foreground, @ColorInt int background) { |
| if (Color.alpha(background) != 255) { |
| Log.wtf(TAG, "background can not be translucent: #" |
| + Integer.toHexString(background)); |
| } |
| if (Color.alpha(foreground) < 255) { |
| // If the foreground is translucent, composite the foreground over the background |
| foreground = compositeColors(foreground, background); |
| } |
| |
| final double luminance1 = calculateLuminance(foreground) + 0.05; |
| final double luminance2 = calculateLuminance(background) + 0.05; |
| |
| // Now return the lighter luminance divided by the darker luminance |
| return Math.max(luminance1, luminance2) / Math.min(luminance1, luminance2); |
| } |
| |
| /** |
| * Convert the ARGB color to its CIE Lab representative components. |
| * |
| * @param color the ARGB color to convert. The alpha component is ignored |
| * @param outLab 3-element array which holds the resulting LAB components |
| */ |
| public static void colorToLAB(@ColorInt int color, @NonNull double[] outLab) { |
| RGBToLAB(Color.red(color), Color.green(color), Color.blue(color), outLab); |
| } |
| |
| /** |
| * Convert RGB components to its CIE Lab representative components. |
| * |
| * <ul> |
| * <li>outLab[0] is L [0 ...100)</li> |
| * <li>outLab[1] is a [-128...127)</li> |
| * <li>outLab[2] is b [-128...127)</li> |
| * </ul> |
| * |
| * @param r red component value [0..255] |
| * @param g green component value [0..255] |
| * @param b blue component value [0..255] |
| * @param outLab 3-element array which holds the resulting LAB components |
| */ |
| public static void RGBToLAB(@IntRange(from = 0x0, to = 0xFF) int r, |
| @IntRange(from = 0x0, to = 0xFF) int g, @IntRange(from = 0x0, to = 0xFF) int b, |
| @NonNull double[] outLab) { |
| // First we convert RGB to XYZ |
| RGBToXYZ(r, g, b, outLab); |
| // outLab now contains XYZ |
| XYZToLAB(outLab[0], outLab[1], outLab[2], outLab); |
| // outLab now contains LAB representation |
| } |
| |
| /** |
| * Convert the ARGB color to it's CIE XYZ representative components. |
| * |
| * <p>The resulting XYZ representation will use the D65 illuminant and the CIE |
| * 2° Standard Observer (1931).</p> |
| * |
| * <ul> |
| * <li>outXyz[0] is X [0 ...95.047)</li> |
| * <li>outXyz[1] is Y [0...100)</li> |
| * <li>outXyz[2] is Z [0...108.883)</li> |
| * </ul> |
| * |
| * @param color the ARGB color to convert. The alpha component is ignored |
| * @param outXyz 3-element array which holds the resulting LAB components |
| */ |
| public static void colorToXYZ(@ColorInt int color, @NonNull double[] outXyz) { |
| RGBToXYZ(Color.red(color), Color.green(color), Color.blue(color), outXyz); |
| } |
| |
| /** |
| * Convert RGB components to it's CIE XYZ representative components. |
| * |
| * <p>The resulting XYZ representation will use the D65 illuminant and the CIE |
| * 2° Standard Observer (1931).</p> |
| * |
| * <ul> |
| * <li>outXyz[0] is X [0 ...95.047)</li> |
| * <li>outXyz[1] is Y [0...100)</li> |
| * <li>outXyz[2] is Z [0...108.883)</li> |
| * </ul> |
| * |
| * @param r red component value [0..255] |
| * @param g green component value [0..255] |
| * @param b blue component value [0..255] |
| * @param outXyz 3-element array which holds the resulting XYZ components |
| */ |
| public static void RGBToXYZ(@IntRange(from = 0x0, to = 0xFF) int r, |
| @IntRange(from = 0x0, to = 0xFF) int g, @IntRange(from = 0x0, to = 0xFF) int b, |
| @NonNull double[] outXyz) { |
| if (outXyz.length != 3) { |
| throw new IllegalArgumentException("outXyz must have a length of 3."); |
| } |
| |
| double sr = r / 255.0; |
| sr = sr < 0.04045 ? sr / 12.92 : Math.pow((sr + 0.055) / 1.055, 2.4); |
| double sg = g / 255.0; |
| sg = sg < 0.04045 ? sg / 12.92 : Math.pow((sg + 0.055) / 1.055, 2.4); |
| double sb = b / 255.0; |
| sb = sb < 0.04045 ? sb / 12.92 : Math.pow((sb + 0.055) / 1.055, 2.4); |
| |
| outXyz[0] = 100 * (sr * 0.4124 + sg * 0.3576 + sb * 0.1805); |
| outXyz[1] = 100 * (sr * 0.2126 + sg * 0.7152 + sb * 0.0722); |
| outXyz[2] = 100 * (sr * 0.0193 + sg * 0.1192 + sb * 0.9505); |
| } |
| |
| /** |
| * Converts a color from CIE XYZ to CIE Lab representation. |
| * |
| * <p>This method expects the XYZ representation to use the D65 illuminant and the CIE |
| * 2° Standard Observer (1931).</p> |
| * |
| * <ul> |
| * <li>outLab[0] is L [0 ...100)</li> |
| * <li>outLab[1] is a [-128...127)</li> |
| * <li>outLab[2] is b [-128...127)</li> |
| * </ul> |
| * |
| * @param x X component value [0...95.047) |
| * @param y Y component value [0...100) |
| * @param z Z component value [0...108.883) |
| * @param outLab 3-element array which holds the resulting Lab components |
| */ |
| public static void XYZToLAB(@FloatRange(from = 0f, to = XYZ_WHITE_REFERENCE_X) double x, |
| @FloatRange(from = 0f, to = XYZ_WHITE_REFERENCE_Y) double y, |
| @FloatRange(from = 0f, to = XYZ_WHITE_REFERENCE_Z) double z, |
| @NonNull double[] outLab) { |
| if (outLab.length != 3) { |
| throw new IllegalArgumentException("outLab must have a length of 3."); |
| } |
| x = pivotXyzComponent(x / XYZ_WHITE_REFERENCE_X); |
| y = pivotXyzComponent(y / XYZ_WHITE_REFERENCE_Y); |
| z = pivotXyzComponent(z / XYZ_WHITE_REFERENCE_Z); |
| outLab[0] = Math.max(0, 116 * y - 16); |
| outLab[1] = 500 * (x - y); |
| outLab[2] = 200 * (y - z); |
| } |
| |
| /** |
| * Converts a color from CIE Lab to CIE XYZ representation. |
| * |
| * <p>The resulting XYZ representation will use the D65 illuminant and the CIE |
| * 2° Standard Observer (1931).</p> |
| * |
| * <ul> |
| * <li>outXyz[0] is X [0 ...95.047)</li> |
| * <li>outXyz[1] is Y [0...100)</li> |
| * <li>outXyz[2] is Z [0...108.883)</li> |
| * </ul> |
| * |
| * @param l L component value [0...100) |
| * @param a A component value [-128...127) |
| * @param b B component value [-128...127) |
| * @param outXyz 3-element array which holds the resulting XYZ components |
| */ |
| public static void LABToXYZ(@FloatRange(from = 0f, to = 100) final double l, |
| @FloatRange(from = -128, to = 127) final double a, |
| @FloatRange(from = -128, to = 127) final double b, |
| @NonNull double[] outXyz) { |
| final double fy = (l + 16) / 116; |
| final double fx = a / 500 + fy; |
| final double fz = fy - b / 200; |
| |
| double tmp = Math.pow(fx, 3); |
| final double xr = tmp > XYZ_EPSILON ? tmp : (116 * fx - 16) / XYZ_KAPPA; |
| final double yr = l > XYZ_KAPPA * XYZ_EPSILON ? Math.pow(fy, 3) : l / XYZ_KAPPA; |
| |
| tmp = Math.pow(fz, 3); |
| final double zr = tmp > XYZ_EPSILON ? tmp : (116 * fz - 16) / XYZ_KAPPA; |
| |
| outXyz[0] = xr * XYZ_WHITE_REFERENCE_X; |
| outXyz[1] = yr * XYZ_WHITE_REFERENCE_Y; |
| outXyz[2] = zr * XYZ_WHITE_REFERENCE_Z; |
| } |
| |
| /** |
| * Converts a color from CIE XYZ to its RGB representation. |
| * |
| * <p>This method expects the XYZ representation to use the D65 illuminant and the CIE |
| * 2° Standard Observer (1931).</p> |
| * |
| * @param x X component value [0...95.047) |
| * @param y Y component value [0...100) |
| * @param z Z component value [0...108.883) |
| * @return int containing the RGB representation |
| */ |
| @ColorInt |
| public static int XYZToColor(@FloatRange(from = 0f, to = XYZ_WHITE_REFERENCE_X) double x, |
| @FloatRange(from = 0f, to = XYZ_WHITE_REFERENCE_Y) double y, |
| @FloatRange(from = 0f, to = XYZ_WHITE_REFERENCE_Z) double z) { |
| double r = (x * 3.2406 + y * -1.5372 + z * -0.4986) / 100; |
| double g = (x * -0.9689 + y * 1.8758 + z * 0.0415) / 100; |
| double b = (x * 0.0557 + y * -0.2040 + z * 1.0570) / 100; |
| |
| r = r > 0.0031308 ? 1.055 * Math.pow(r, 1 / 2.4) - 0.055 : 12.92 * r; |
| g = g > 0.0031308 ? 1.055 * Math.pow(g, 1 / 2.4) - 0.055 : 12.92 * g; |
| b = b > 0.0031308 ? 1.055 * Math.pow(b, 1 / 2.4) - 0.055 : 12.92 * b; |
| |
| return Color.rgb( |
| constrain((int) Math.round(r * 255), 0, 255), |
| constrain((int) Math.round(g * 255), 0, 255), |
| constrain((int) Math.round(b * 255), 0, 255)); |
| } |
| |
| /** |
| * Converts a color from CIE Lab to its RGB representation. |
| * |
| * @param l L component value [0...100] |
| * @param a A component value [-128...127] |
| * @param b B component value [-128...127] |
| * @return int containing the RGB representation |
| */ |
| @ColorInt |
| public static int LABToColor(@FloatRange(from = 0f, to = 100) final double l, |
| @FloatRange(from = -128, to = 127) final double a, |
| @FloatRange(from = -128, to = 127) final double b) { |
| final double[] result = getTempDouble3Array(); |
| LABToXYZ(l, a, b, result); |
| return XYZToColor(result[0], result[1], result[2]); |
| } |
| |
| private static int constrain(int amount, int low, int high) { |
| return amount < low ? low : (amount > high ? high : amount); |
| } |
| |
| private static float constrain(float amount, float low, float high) { |
| return amount < low ? low : (amount > high ? high : amount); |
| } |
| |
| private static double pivotXyzComponent(double component) { |
| return component > XYZ_EPSILON |
| ? Math.pow(component, 1 / 3.0) |
| : (XYZ_KAPPA * component + 16) / 116; |
| } |
| |
| public static double[] getTempDouble3Array() { |
| double[] result = TEMP_ARRAY.get(); |
| if (result == null) { |
| result = new double[3]; |
| TEMP_ARRAY.set(result); |
| } |
| return result; |
| } |
| |
| /** |
| * Convert HSL (hue-saturation-lightness) components to a RGB color. |
| * <ul> |
| * <li>hsl[0] is Hue [0 .. 360)</li> |
| * <li>hsl[1] is Saturation [0...1]</li> |
| * <li>hsl[2] is Lightness [0...1]</li> |
| * </ul> |
| * If hsv values are out of range, they are pinned. |
| * |
| * @param hsl 3-element array which holds the input HSL components |
| * @return the resulting RGB color |
| */ |
| @ColorInt |
| public static int HSLToColor(@NonNull float[] hsl) { |
| final float h = hsl[0]; |
| final float s = hsl[1]; |
| final float l = hsl[2]; |
| |
| final float c = (1f - Math.abs(2 * l - 1f)) * s; |
| final float m = l - 0.5f * c; |
| final float x = c * (1f - Math.abs((h / 60f % 2f) - 1f)); |
| |
| final int hueSegment = (int) h / 60; |
| |
| int r = 0, g = 0, b = 0; |
| |
| switch (hueSegment) { |
| case 0: |
| r = Math.round(255 * (c + m)); |
| g = Math.round(255 * (x + m)); |
| b = Math.round(255 * m); |
| break; |
| case 1: |
| r = Math.round(255 * (x + m)); |
| g = Math.round(255 * (c + m)); |
| b = Math.round(255 * m); |
| break; |
| case 2: |
| r = Math.round(255 * m); |
| g = Math.round(255 * (c + m)); |
| b = Math.round(255 * (x + m)); |
| break; |
| case 3: |
| r = Math.round(255 * m); |
| g = Math.round(255 * (x + m)); |
| b = Math.round(255 * (c + m)); |
| break; |
| case 4: |
| r = Math.round(255 * (x + m)); |
| g = Math.round(255 * m); |
| b = Math.round(255 * (c + m)); |
| break; |
| case 5: |
| case 6: |
| r = Math.round(255 * (c + m)); |
| g = Math.round(255 * m); |
| b = Math.round(255 * (x + m)); |
| break; |
| } |
| |
| r = constrain(r, 0, 255); |
| g = constrain(g, 0, 255); |
| b = constrain(b, 0, 255); |
| |
| return Color.rgb(r, g, b); |
| } |
| |
| /** |
| * Convert the ARGB color to its HSL (hue-saturation-lightness) components. |
| * <ul> |
| * <li>outHsl[0] is Hue [0 .. 360)</li> |
| * <li>outHsl[1] is Saturation [0...1]</li> |
| * <li>outHsl[2] is Lightness [0...1]</li> |
| * </ul> |
| * |
| * @param color the ARGB color to convert. The alpha component is ignored |
| * @param outHsl 3-element array which holds the resulting HSL components |
| */ |
| public static void colorToHSL(@ColorInt int color, @NonNull float[] outHsl) { |
| RGBToHSL(Color.red(color), Color.green(color), Color.blue(color), outHsl); |
| } |
| |
| /** |
| * Convert RGB components to HSL (hue-saturation-lightness). |
| * <ul> |
| * <li>outHsl[0] is Hue [0 .. 360)</li> |
| * <li>outHsl[1] is Saturation [0...1]</li> |
| * <li>outHsl[2] is Lightness [0...1]</li> |
| * </ul> |
| * |
| * @param r red component value [0..255] |
| * @param g green component value [0..255] |
| * @param b blue component value [0..255] |
| * @param outHsl 3-element array which holds the resulting HSL components |
| */ |
| public static void RGBToHSL(@IntRange(from = 0x0, to = 0xFF) int r, |
| @IntRange(from = 0x0, to = 0xFF) int g, @IntRange(from = 0x0, to = 0xFF) int b, |
| @NonNull float[] outHsl) { |
| final float rf = r / 255f; |
| final float gf = g / 255f; |
| final float bf = b / 255f; |
| |
| final float max = Math.max(rf, Math.max(gf, bf)); |
| final float min = Math.min(rf, Math.min(gf, bf)); |
| final float deltaMaxMin = max - min; |
| |
| float h, s; |
| float l = (max + min) / 2f; |
| |
| if (max == min) { |
| // Monochromatic |
| h = s = 0f; |
| } else { |
| if (max == rf) { |
| h = ((gf - bf) / deltaMaxMin) % 6f; |
| } else if (max == gf) { |
| h = ((bf - rf) / deltaMaxMin) + 2f; |
| } else { |
| h = ((rf - gf) / deltaMaxMin) + 4f; |
| } |
| |
| s = deltaMaxMin / (1f - Math.abs(2f * l - 1f)); |
| } |
| |
| h = (h * 60f) % 360f; |
| if (h < 0) { |
| h += 360f; |
| } |
| |
| outHsl[0] = constrain(h, 0f, 360f); |
| outHsl[1] = constrain(s, 0f, 1f); |
| outHsl[2] = constrain(l, 0f, 1f); |
| } |
| |
| } |
| } |
