Add and implement inter character justification (99893a1e) · Commits · e / os / android_frameworks_base

core/api/current.txt

+2 −0

Original line number	Diff line number	Diff line
		@@ -17874,6 +17874,7 @@ package android.graphics.text {
		field public static final int HYPHENATION_FREQUENCY_FULL = 2; // 0x2
		field public static final int HYPHENATION_FREQUENCY_NONE = 0; // 0x0
		field public static final int HYPHENATION_FREQUENCY_NORMAL = 1; // 0x1
		field @FlaggedApi("com.android.text.flags.inter_character_justification") public static final int JUSTIFICATION_MODE_INTER_CHARACTER = 2; // 0x2
		field public static final int JUSTIFICATION_MODE_INTER_WORD = 1; // 0x1
		field public static final int JUSTIFICATION_MODE_NONE = 0; // 0x0
		}
		@@ -46946,6 +46947,7 @@ package android.text {
		field @NonNull public static final android.text.Layout.TextInclusionStrategy INCLUSION_STRATEGY_ANY_OVERLAP;
		field @NonNull public static final android.text.Layout.TextInclusionStrategy INCLUSION_STRATEGY_CONTAINS_ALL;
		field @NonNull public static final android.text.Layout.TextInclusionStrategy INCLUSION_STRATEGY_CONTAINS_CENTER;
		field @FlaggedApi("com.android.text.flags.inter_character_justification") public static final int JUSTIFICATION_MODE_INTER_CHARACTER = 2; // 0x2
		field public static final int JUSTIFICATION_MODE_INTER_WORD = 1; // 0x1
		field public static final int JUSTIFICATION_MODE_NONE = 0; // 0x0
		}

core/java/android/text/Layout.java

+13 −5

Original line number	Diff line number	Diff line
		@@ -152,7 +152,8 @@ public abstract class Layout {
		/** @hide */
		@IntDef(prefix = { "JUSTIFICATION_MODE_" }, value = {
		LineBreaker.JUSTIFICATION_MODE_NONE,
		LineBreaker.JUSTIFICATION_MODE_INTER_WORD
		LineBreaker.JUSTIFICATION_MODE_INTER_WORD,
		LineBreaker.JUSTIFICATION_MODE_INTER_CHARACTER,
		})
		@Retention(RetentionPolicy.SOURCE)
		public @interface JustificationMode {}
		@@ -168,6 +169,13 @@ public abstract class Layout {
		public static final int JUSTIFICATION_MODE_INTER_WORD =
		LineBreaker.JUSTIFICATION_MODE_INTER_WORD;

		/**
		* Value for justification mode indicating the text is justified by stretching letter spacing.
		*/
		@FlaggedApi(FLAG_INTER_CHARACTER_JUSTIFICATION)
		public static final int JUSTIFICATION_MODE_INTER_CHARACTER =
		LineBreaker.JUSTIFICATION_MODE_INTER_CHARACTER;

		/*
		* Line spacing multiplier for default line spacing.
		*/
		@@ -809,7 +817,7 @@ public abstract class Layout {
		getEllipsisStart(lineNum) + getEllipsisCount(lineNum),
		isFallbackLineSpacingEnabled());
		if (justify) {
		tl.justify(right - left - indentWidth);
		tl.justify(mJustificationMode, right - left - indentWidth);
		}
		tl.draw(canvas, x, ltop, lbaseline, lbottom);
		}
		@@ -1058,7 +1066,7 @@ public abstract class Layout {
		getEllipsisStart(line), getEllipsisStart(line) + getEllipsisCount(line),
		isFallbackLineSpacingEnabled());
		if (isJustificationRequired(line)) {
		tl.justify(getJustifyWidth(line));
		tl.justify(mJustificationMode, getJustifyWidth(line));
		}
		tl.metrics(null, rectF, false, null);

		@@ -1794,7 +1802,7 @@ public abstract class Layout {
		getEllipsisStart(line), getEllipsisStart(line) + getEllipsisCount(line),
		isFallbackLineSpacingEnabled());
		if (isJustificationRequired(line)) {
		tl.justify(getJustifyWidth(line));
		tl.justify(mJustificationMode, getJustifyWidth(line));
		}
		final float width = tl.metrics(null, null, mUseBoundsForWidth, null);
		TextLine.recycle(tl);
		@@ -1882,7 +1890,7 @@ public abstract class Layout {
		getEllipsisStart(line), getEllipsisStart(line) + getEllipsisCount(line),
		isFallbackLineSpacingEnabled());
		if (isJustificationRequired(line)) {
		tl.justify(getJustifyWidth(line));
		tl.justify(mJustificationMode, getJustifyWidth(line));
		}
		final float width = tl.metrics(null, null, mUseBoundsForWidth, null);
		TextLine.recycle(tl);

core/java/android/text/TextLine.java

+56 −12

Original line number	Diff line number	Diff line
		@@ -100,9 +100,25 @@ public class TextLine {

		// Additional width of whitespace for justification. This value is per whitespace, thus
		// the line width will increase by mAddedWidthForJustify x (number of stretchable whitespaces).
		private float mAddedWidthForJustify;
		private float mAddedWordSpacingInPx;
		private float mAddedLetterSpacingInPx;
		private boolean mIsJustifying;

		@VisibleForTesting
		public float getAddedWordSpacingInPx() {
		return mAddedWordSpacingInPx;
		}

		@VisibleForTesting
		public float getAddedLetterSpacingInPx() {
		return mAddedLetterSpacingInPx;
		}

		@VisibleForTesting
		public boolean isJustifying() {
		return mIsJustifying;
		}

		private final TextPaint mWorkPaint = new TextPaint();
		private final TextPaint mActivePaint = new TextPaint();
		@UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
		@@ -259,7 +275,7 @@ public class TextLine {
		}
		}
		mTabs = tabStops;
		mAddedWidthForJustify = 0;
		mAddedWordSpacingInPx = 0;
		mIsJustifying = false;

		mEllipsisStart = ellipsisStart != ellipsisEnd ? ellipsisStart : 0;
		@@ -274,19 +290,42 @@ public class TextLine {
		* Justify the line to the given width.
		*/
		@VisibleForTesting(visibility = VisibleForTesting.Visibility.PACKAGE)
		public void justify(float justifyWidth) {
		public void justify(@Layout.JustificationMode int justificationMode, float justifyWidth) {
		int end = mLen;
		while (end > 0 && isLineEndSpace(mText.charAt(mStart + end - 1))) {
		end--;
		}
		if (justificationMode == Layout.JUSTIFICATION_MODE_INTER_WORD) {
		float width = Math.abs(measure(end, false, null, null, null));
		final int spaces = countStretchableSpaces(0, end);
		if (spaces == 0) {
		// There are no stretchable spaces, so we can't help the justification by adding any
		// width.
		return;
		}
		final float width = Math.abs(measure(end, false, null, null, null));
		mAddedWidthForJustify = (justifyWidth - width) / spaces;
		mAddedWordSpacingInPx = (justifyWidth - width) / spaces;
		mAddedLetterSpacingInPx = 0;
		} else { // justificationMode == Layout.JUSTIFICATION_MODE_INTER_CHARACTER
		LineInfo lineInfo = new LineInfo();
		float width = Math.abs(measure(end, false, null, null, lineInfo));

		int lettersCount = lineInfo.getClusterCount();
		if (lettersCount < 2) {
		return;
		}
		mAddedLetterSpacingInPx = (justifyWidth - width) / (lettersCount - 1);
		if (mAddedLetterSpacingInPx > 0.03) {
		// If the letter spacing is more than 0.03em, the ligatures are automatically
		// disabled, so re-calculate everything without ligatures.
		final String oldFontFeatures = mPaint.getFontFeatureSettings();
		mPaint.setFontFeatureSettings(oldFontFeatures + ", \"liga\" off, \"cliga\" off");
		width = Math.abs(measure(end, false, null, null, lineInfo));
		lettersCount = lineInfo.getClusterCount();
		mAddedLetterSpacingInPx = (justifyWidth - width) / (lettersCount - 1);
		mPaint.setFontFeatureSettings(oldFontFeatures);
		}
		mAddedWordSpacingInPx = 0;
		}
		mIsJustifying = true;
		}

		@@ -529,6 +568,9 @@ public class TextLine {
		throw new IndexOutOfBoundsException(
		"offset(" + offset + ") should be less than line limit(" + mLen + ")");
		}
		if (lineInfo != null) {
		lineInfo.setClusterCount(0);
		}
		final int target = trailing ? offset - 1 : offset;
		if (target < 0) {
		return 0;
		@@ -1076,7 +1118,8 @@ public class TextLine {
		TextPaint wp = mWorkPaint;
		wp.set(mPaint);
		if (mIsJustifying) {
		wp.setWordSpacing(mAddedWidthForJustify);
		wp.setWordSpacing(mAddedWordSpacingInPx);
		wp.setLetterSpacing(mAddedLetterSpacingInPx / wp.getTextSize()); // Convert to Em
		}

		int spanStart = runStart;
		@@ -1277,7 +1320,8 @@ public class TextLine {
		@Nullable float[] advances, int advancesIndex, @Nullable LineInfo lineInfo,
		int runFlag) {
		if (mIsJustifying) {
		wp.setWordSpacing(mAddedWidthForJustify);
		wp.setWordSpacing(mAddedWordSpacingInPx);
		wp.setLetterSpacing(mAddedLetterSpacingInPx / wp.getTextSize()); // Convert to Em
		}
		// Get metrics first (even for empty strings or "0" width runs)
		if (drawBounds != null && fmi == null) {

core/tests/coretests/src/android/text/TextLineJustificationTest.kt

0 → 100644

+129 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2024 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 android.text

		import android.platform.test.flag.junit.DeviceFlagsValueProvider
		import androidx.test.ext.junit.runners.AndroidJUnit4
		import androidx.test.filters.SmallTest
		import com.google.common.truth.Truth.assertThat
		import org.junit.Rule
		import org.junit.Test
		import org.junit.runner.RunWith

		@SmallTest
		@RunWith(AndroidJUnit4::class)
		class TextLineJustificationTest {

		@Rule
		@JvmField
		val mCheckFlagsRule = DeviceFlagsValueProvider.createCheckFlagsRule()

		private val PAINT = TextPaint().apply {
		textSize = 10f // make 1em = 10px
		}

		private fun makeTextLine(cs: CharSequence, paint: TextPaint) = TextLine.obtain().apply {
		set(paint, cs, 0, cs.length, Layout.DIR_LEFT_TO_RIGHT, Layout.DIRS_ALL_LEFT_TO_RIGHT, false,
		null, 0, 0, false)
		}

		private fun getClusterCount(cs: CharSequence, paint: TextPaint) = TextLine.LineInfo().apply {
		makeTextLine(cs, paint).also {
		it.metrics(null, null, false, this)
		TextLine.recycle(it)
		}
		}.clusterCount

		fun justifyTest_WithoutJustify() {
		val line = "Hello, World."
		val tl = makeTextLine(line, PAINT)

		// Without calling justify method, justifying should be false and all added spaces should
		// be zeros.
		assertThat(tl.isJustifying).isFalse()
		assertThat(tl.addedWordSpacingInPx).isEqualTo(0)
		assertThat(tl.addedLetterSpacingInPx).isEqualTo(0)
		}

		@Test
		fun justifyTest_IntrCharacter_Latin() {
		val line = "Hello, World."
		val clusterCount = getClusterCount(line, PAINT)
		val originalWidth = Layout.getDesiredWidth(line, PAINT)
		val extraWidth = 100f

		val tl = makeTextLine(line, PAINT)
		tl.justify(Layout.JUSTIFICATION_MODE_INTER_CHARACTER, originalWidth + extraWidth)

		assertThat(tl.isJustifying).isTrue()
		assertThat(tl.addedWordSpacingInPx).isEqualTo(0)
		assertThat(tl.addedLetterSpacingInPx).isEqualTo(extraWidth / (clusterCount - 1))

		TextLine.recycle(tl)
		}

		@Test
		fun justifyTest_IntrCharacter_Japanese() {
		val line = "\u672C\u65E5\u306F\u6674\u5929\u306A\u308A\u3002"
		val clusterCount = getClusterCount(line, PAINT)
		val originalWidth = Layout.getDesiredWidth(line, PAINT)
		val extraWidth = 100f

		val tl = makeTextLine(line, PAINT)
		tl.justify(Layout.JUSTIFICATION_MODE_INTER_CHARACTER, originalWidth + extraWidth)

		assertThat(tl.isJustifying).isTrue()
		assertThat(tl.addedWordSpacingInPx).isEqualTo(0)
		assertThat(tl.addedLetterSpacingInPx).isEqualTo(extraWidth / (clusterCount - 1))

		TextLine.recycle(tl)
		}

		@Test
		fun justifyTest_IntrWord_Latin() {
		val line = "Hello, World."
		val originalWidth = Layout.getDesiredWidth(line, PAINT)
		val extraWidth = 100f

		val tl = makeTextLine(line, PAINT)
		tl.justify(Layout.JUSTIFICATION_MODE_INTER_WORD, originalWidth + extraWidth)

		assertThat(tl.isJustifying).isTrue()
		// This text contains only one whitespace, so word spacing should be same to the extraWidth.
		assertThat(tl.addedWordSpacingInPx).isEqualTo(extraWidth)
		assertThat(tl.addedLetterSpacingInPx).isEqualTo(0)

		TextLine.recycle(tl)
		}

		@Test
		fun justifyTest_IntrWord_Japanese() {
		val line = "\u672C\u65E5\u306F\u6674\u0020\u5929\u306A\u308A\u3002"
		val originalWidth = Layout.getDesiredWidth(line, PAINT)
		val extraWidth = 100f

		val tl = makeTextLine(line, PAINT)
		tl.justify(Layout.JUSTIFICATION_MODE_INTER_WORD, originalWidth + extraWidth)

		assertThat(tl.isJustifying).isTrue()
		// This text contains only one whitespace, so word spacing should be same to the extraWidth.
		assertThat(tl.addedWordSpacingInPx).isEqualTo(extraWidth)
		assertThat(tl.addedLetterSpacingInPx).isEqualTo(0)

		TextLine.recycle(tl)
		}
		}
		No newline at end of file

core/tests/coretests/src/android/text/TextLineTest.java

+1 −1

Original line number	Diff line number	Diff line
		@@ -53,7 +53,7 @@ public class TextLineTest {
		final float originalWidth = tl.metrics(null, null, false, null);
		final float expandedWidth = 2 * originalWidth;

		tl.justify(expandedWidth);
		tl.justify(Layout.JUSTIFICATION_MODE_INTER_WORD, expandedWidth);
		final float newWidth = tl.metrics(null, null, false, null);
		TextLine.recycle(tl);
		return Math.abs(newWidth - expandedWidth) < 0.5;