Merge "fix(high contrast text): Fix the color calculation used in high contrast text" into main (eb762903) · Commits · e / os / android_frameworks_base

libs/hwui/Android.bp

+1 −0

Original line number	Diff line number	Diff line
		@@ -779,6 +779,7 @@ cc_test {
		"tests/unit/CommonPoolTests.cpp",
		"tests/unit/DamageAccumulatorTests.cpp",
		"tests/unit/DeferredLayerUpdaterTests.cpp",
		"tests/unit/DrawTextFunctorTest.cpp",
		"tests/unit/EglManagerTests.cpp",
		"tests/unit/FatVectorTests.cpp",
		"tests/unit/GraphicsStatsServiceTests.cpp",

libs/hwui/hwui/DrawTextFunctor.h

+37 −17

Original line number	Diff line number	Diff line
		@@ -76,6 +76,41 @@ static void simplifyPaint(int color, Paint* paint) {
		paint->setBlendMode(SkBlendMode::kSrcOver);
		}

		namespace {

		static bool shouldDarkenTextForHighContrast(const uirenderer::Lab& lab) {
		// LINT.IfChange(hct_darken)
		return lab.L <= 50;
		// LINT.ThenChange(/core/java/android/text/Layout.java:hct_darken)
		}

		} // namespace

		static void adjustHighContrastInnerTextColor(uirenderer::Lab* lab) {
		bool darken = shouldDarkenTextForHighContrast(*lab);
		bool isGrayscale = abs(lab->a) < 10 && abs(lab->b) < 10;
		if (isGrayscale) {
		// For near-grayscale text we first remove all color.
		lab->a = lab->b = 0;
		if (lab->L > 40 && lab->L < 60) {
		// Text near "middle gray" is pushed to a more contrasty gray.
		lab->L = darken ? 20 : 80;
		} else {
		// Other grayscale text is pushed completely white or black.
		lab->L = darken ? 0 : 100;
		}
		} else {
		// For color text we ensure the text is bright enough (for light text)
		// or dark enough (for dark text) to stand out against the background,
		// without touching the A and B components so we retain color.
		if (darken && lab->L > 20.f) {
		lab->L = 20.0f;
		} else if (!darken && lab->L < 90.f) {
		lab->L = 90.0f;
		}
		}
		}

		class DrawTextFunctor {
		public:
		/**
		@@ -114,10 +149,8 @@ public:
		if (CC_UNLIKELY(canvas->isHighContrastText() && paint.getAlpha() != 0)) {
		// high contrast draw path
		int color = paint.getColor();
		// LINT.IfChange(hct_darken)
		uirenderer::Lab lab = uirenderer::sRGBToLab(color);
		bool darken = lab.L <= 50;
		// LINT.ThenChange(/core/java/android/text/Layout.java:hct_darken)
		bool darken = shouldDarkenTextForHighContrast(lab);

		// outline
		gDrawTextBlobMode = DrawTextBlobMode::HctOutline;
		@@ -130,20 +163,7 @@ public:
		gDrawTextBlobMode = DrawTextBlobMode::HctInner;
		Paint innerPaint(paint);
		if (flags::high_contrast_text_inner_text_color()) {
		// Preserve some color information while still ensuring sufficient contrast.
		// Thus we increase the lightness to make the color stand out against a black
		// background, and vice-versa. For grayscale, we retain some gray to indicate
		// states like disabled or to distinguish links.
		bool isGrayscale = abs(lab.a) < 1 && abs(lab.b) < 1;
		if (isGrayscale) {
		if (darken) {
		lab.L = lab.L < 40 ? 0 : 20;
		} else {
		lab.L = lab.L > 60 ? 100 : 80;
		}
		} else {
		lab.L = darken ? 20 : 90;
		}
		adjustHighContrastInnerTextColor(&lab);
		simplifyPaint(uirenderer::LabToSRGB(lab, SK_AlphaOPAQUE), &innerPaint);
		} else {
		simplifyPaint(darken ? SK_ColorBLACK : SK_ColorWHITE, &innerPaint);

libs/hwui/tests/unit/DrawTextFunctorTest.cpp

0 → 100644

+88 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2025 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.
		*/

		#include <gtest/gtest.h>

		#include "hwui/DrawTextFunctor.h"

		using namespace android;

		namespace {

		void testHighContrastInnerTextColor(float originalL, float originalA, float originalB,
		float expectedL, float expectedA, float expectedB) {
		uirenderer::Lab color = {originalL, originalA, originalB};
		adjustHighContrastInnerTextColor(&color);
		EXPECT_FLOAT_EQ(color.L, expectedL);
		EXPECT_FLOAT_EQ(color.a, expectedA);
		EXPECT_FLOAT_EQ(color.b, expectedB);
		}

		TEST(DrawTextFunctorTest, BlackUnaffected) {
		testHighContrastInnerTextColor(0, 0, 0, 0, 0, 0);
		}

		TEST(DrawTextFunctorTest, WhiteUnaffected) {
		testHighContrastInnerTextColor(100, 0, 0, 100, 0, 0);
		}

		TEST(DrawTextFunctorTest, DarkGrayPushedToWhite) {
		testHighContrastInnerTextColor(10, 0, 0, 0, 0, 0);
		testHighContrastInnerTextColor(20, 0, 0, 0, 0, 0);
		}

		TEST(DrawTextFunctorTest, LightGrayPushedToWhite) {
		testHighContrastInnerTextColor(80, 0, 0, 100, 0, 0);
		testHighContrastInnerTextColor(90, 0, 0, 100, 0, 0);
		}

		TEST(DrawTextFunctorTest, MiddleDarkGrayPushedToDarkGray) {
		testHighContrastInnerTextColor(41, 0, 0, 20, 0, 0);
		testHighContrastInnerTextColor(49, 0, 0, 20, 0, 0);
		}

		TEST(DrawTextFunctorTest, MiddleLightGrayPushedToLightGray) {
		testHighContrastInnerTextColor(51, 0, 0, 80, 0, 0);
		testHighContrastInnerTextColor(59, 0, 0, 80, 0, 0);
		}

		TEST(DrawTextFunctorTest, PaleColorTreatedAsGrayscaleAndPushedToWhite) {
		testHighContrastInnerTextColor(75, 5, -5, 100, 0, 0);
		testHighContrastInnerTextColor(85, -6, 8, 100, 0, 0);
		}

		TEST(DrawTextFunctorTest, PaleColorTreatedAsGrayscaleAndPushedToBlack) {
		testHighContrastInnerTextColor(25, 5, -5, 0, 0, 0);
		testHighContrastInnerTextColor(35, -6, 8, 0, 0, 0);
		}

		TEST(DrawTextFunctorTest, ColorfulColorIsLightened) {
		testHighContrastInnerTextColor(70, 100, -100, 90, 100, -100);
		}

		TEST(DrawTextFunctorTest, ColorfulLightColorIsUntouched) {
		testHighContrastInnerTextColor(95, 100, -100, 95, 100, -100);
		}

		TEST(DrawTextFunctorTest, ColorfulColorIsDarkened) {
		testHighContrastInnerTextColor(30, 100, -100, 20, 100, -100);
		}

		TEST(DrawTextFunctorTest, ColorfulDarkColorIsUntouched) {
		testHighContrastInnerTextColor(5, 100, -100, 5, 100, -100);
		}

		} // namespace