Java tutorial
/* * Copyright (C) 2006 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.annotation.IntDef; import android.annotation.IntRange; import android.annotation.UnsupportedAppUsage; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Path; import android.graphics.Rect; import android.text.method.TextKeyListener; import android.text.style.AlignmentSpan; import android.text.style.LeadingMarginSpan; import android.text.style.LeadingMarginSpan.LeadingMarginSpan2; import android.text.style.LineBackgroundSpan; import android.text.style.ParagraphStyle; import android.text.style.ReplacementSpan; import android.text.style.TabStopSpan; import com.android.internal.annotations.VisibleForTesting; import com.android.internal.util.ArrayUtils; import com.android.internal.util.GrowingArrayUtils; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.util.Arrays; /** * A base class that manages text layout in visual elements on * the screen. * <p>For text that will be edited, use a {@link DynamicLayout}, * which will be updated as the text changes. * For text that will not change, use a {@link StaticLayout}. */ public abstract class Layout { /** @hide */ @IntDef(prefix = { "BREAK_STRATEGY_" }, value = { BREAK_STRATEGY_SIMPLE, BREAK_STRATEGY_HIGH_QUALITY, BREAK_STRATEGY_BALANCED }) @Retention(RetentionPolicy.SOURCE) public @interface BreakStrategy { } /** * Value for break strategy indicating simple line breaking. Automatic hyphens are not added * (though soft hyphens are respected), and modifying text generally doesn't affect the layout * before it (which yields a more consistent user experience when editing), but layout may not * be the highest quality. */ public static final int BREAK_STRATEGY_SIMPLE = 0; /** * Value for break strategy indicating high quality line breaking, including automatic * hyphenation and doing whole-paragraph optimization of line breaks. */ public static final int BREAK_STRATEGY_HIGH_QUALITY = 1; /** * Value for break strategy indicating balanced line breaking. The breaks are chosen to * make all lines as close to the same length as possible, including automatic hyphenation. */ public static final int BREAK_STRATEGY_BALANCED = 2; /** @hide */ @IntDef(prefix = { "HYPHENATION_FREQUENCY_" }, value = { HYPHENATION_FREQUENCY_NORMAL, HYPHENATION_FREQUENCY_FULL, HYPHENATION_FREQUENCY_NONE }) @Retention(RetentionPolicy.SOURCE) public @interface HyphenationFrequency { } /** * Value for hyphenation frequency indicating no automatic hyphenation. Useful * for backward compatibility, and for cases where the automatic hyphenation algorithm results * in incorrect hyphenation. Mid-word breaks may still happen when a word is wider than the * layout and there is otherwise no valid break. Soft hyphens are ignored and will not be used * as suggestions for potential line breaks. */ public static final int HYPHENATION_FREQUENCY_NONE = 0; /** * Value for hyphenation frequency indicating a light amount of automatic hyphenation, which * is a conservative default. Useful for informal cases, such as short sentences or chat * messages. */ public static final int HYPHENATION_FREQUENCY_NORMAL = 1; /** * Value for hyphenation frequency indicating the full amount of automatic hyphenation, typical * in typography. Useful for running text and where it's important to put the maximum amount of * text in a screen with limited space. */ public static final int HYPHENATION_FREQUENCY_FULL = 2; private static final ParagraphStyle[] NO_PARA_SPANS = ArrayUtils.emptyArray(ParagraphStyle.class); /** @hide */ @IntDef(prefix = { "JUSTIFICATION_MODE_" }, value = { JUSTIFICATION_MODE_NONE, JUSTIFICATION_MODE_INTER_WORD }) @Retention(RetentionPolicy.SOURCE) public @interface JustificationMode { } /** * Value for justification mode indicating no justification. */ public static final int JUSTIFICATION_MODE_NONE = 0; /** * Value for justification mode indicating the text is justified by stretching word spacing. */ public static final int JUSTIFICATION_MODE_INTER_WORD = 1; /* * Line spacing multiplier for default line spacing. */ public static final float DEFAULT_LINESPACING_MULTIPLIER = 1.0f; /* * Line spacing addition for default line spacing. */ public static final float DEFAULT_LINESPACING_ADDITION = 0.0f; /** * Return how wide a layout must be in order to display the specified text with one line per * paragraph. * * <p>As of O, Uses * {@link TextDirectionHeuristics#FIRSTSTRONG_LTR} as the default text direction heuristics. In * the earlier versions uses {@link TextDirectionHeuristics#LTR} as the default.</p> */ public static float getDesiredWidth(CharSequence source, TextPaint paint) { return getDesiredWidth(source, 0, source.length(), paint); } /** * Return how wide a layout must be in order to display the specified text slice with one * line per paragraph. * * <p>As of O, Uses * {@link TextDirectionHeuristics#FIRSTSTRONG_LTR} as the default text direction heuristics. In * the earlier versions uses {@link TextDirectionHeuristics#LTR} as the default.</p> */ public static float getDesiredWidth(CharSequence source, int start, int end, TextPaint paint) { return getDesiredWidth(source, start, end, paint, TextDirectionHeuristics.FIRSTSTRONG_LTR); } /** * Return how wide a layout must be in order to display the * specified text slice with one line per paragraph. * * @hide */ public static float getDesiredWidth(CharSequence source, int start, int end, TextPaint paint, TextDirectionHeuristic textDir) { return getDesiredWidthWithLimit(source, start, end, paint, textDir, Float.MAX_VALUE); } /** * Return how wide a layout must be in order to display the * specified text slice with one line per paragraph. * * If the measured width exceeds given limit, returns limit value instead. * @hide */ public static float getDesiredWidthWithLimit(CharSequence source, int start, int end, TextPaint paint, TextDirectionHeuristic textDir, float upperLimit) { float need = 0; int next; for (int i = start; i <= end; i = next) { next = TextUtils.indexOf(source, '\n', i, end); if (next < 0) next = end; // note, omits trailing paragraph char float w = measurePara(paint, source, i, next, textDir); if (w > upperLimit) { return upperLimit; } if (w > need) need = w; next++; } return need; } /** * Subclasses of Layout use this constructor to set the display text, * width, and other standard properties. * @param text the text to render * @param paint the default paint for the layout. Styles can override * various attributes of the paint. * @param width the wrapping width for the text. * @param align whether to left, right, or center the text. Styles can * override the alignment. * @param spacingMult factor by which to scale the font size to get the * default line spacing * @param spacingAdd amount to add to the default line spacing */ protected Layout(CharSequence text, TextPaint paint, int width, Alignment align, float spacingMult, float spacingAdd) { this(text, paint, width, align, TextDirectionHeuristics.FIRSTSTRONG_LTR, spacingMult, spacingAdd); } /** * Subclasses of Layout use this constructor to set the display text, * width, and other standard properties. * @param text the text to render * @param paint the default paint for the layout. Styles can override * various attributes of the paint. * @param width the wrapping width for the text. * @param align whether to left, right, or center the text. Styles can * override the alignment. * @param spacingMult factor by which to scale the font size to get the * default line spacing * @param spacingAdd amount to add to the default line spacing * * @hide */ protected Layout(CharSequence text, TextPaint paint, int width, Alignment align, TextDirectionHeuristic textDir, float spacingMult, float spacingAdd) { if (width < 0) throw new IllegalArgumentException("Layout: " + width + " < 0"); // Ensure paint doesn't have baselineShift set. // While normally we don't modify the paint the user passed in, // we were already doing this in Styled.drawUniformRun with both // baselineShift and bgColor. We probably should reevaluate bgColor. if (paint != null) { paint.bgColor = 0; paint.baselineShift = 0; } mText = text; mPaint = paint; mWidth = width; mAlignment = align; mSpacingMult = spacingMult; mSpacingAdd = spacingAdd; mSpannedText = text instanceof Spanned; mTextDir = textDir; } /** @hide */ protected void setJustificationMode(@JustificationMode int justificationMode) { mJustificationMode = justificationMode; } /** * Replace constructor properties of this Layout with new ones. Be careful. */ /* package */ void replaceWith(CharSequence text, TextPaint paint, int width, Alignment align, float spacingmult, float spacingadd) { if (width < 0) { throw new IllegalArgumentException("Layout: " + width + " < 0"); } mText = text; mPaint = paint; mWidth = width; mAlignment = align; mSpacingMult = spacingmult; mSpacingAdd = spacingadd; mSpannedText = text instanceof Spanned; } /** * Draw this Layout on the specified Canvas. */ public void draw(Canvas c) { draw(c, null, null, 0); } /** * Draw this Layout on the specified canvas, with the highlight path drawn * between the background and the text. * * @param canvas the canvas * @param highlight the path of the highlight or cursor; can be null * @param highlightPaint the paint for the highlight * @param cursorOffsetVertical the amount to temporarily translate the * canvas while rendering the highlight */ public void draw(Canvas canvas, Path highlight, Paint highlightPaint, int cursorOffsetVertical) { final long lineRange = getLineRangeForDraw(canvas); int firstLine = TextUtils.unpackRangeStartFromLong(lineRange); int lastLine = TextUtils.unpackRangeEndFromLong(lineRange); if (lastLine < 0) return; drawBackground(canvas, highlight, highlightPaint, cursorOffsetVertical, firstLine, lastLine); drawText(canvas, firstLine, lastLine); } private boolean isJustificationRequired(int lineNum) { if (mJustificationMode == JUSTIFICATION_MODE_NONE) return false; final int lineEnd = getLineEnd(lineNum); return lineEnd < mText.length() && mText.charAt(lineEnd - 1) != '\n'; } private float getJustifyWidth(int lineNum) { Alignment paraAlign = mAlignment; int left = 0; int right = mWidth; final int dir = getParagraphDirection(lineNum); ParagraphStyle[] spans = NO_PARA_SPANS; if (mSpannedText) { Spanned sp = (Spanned) mText; final int start = getLineStart(lineNum); final boolean isFirstParaLine = (start == 0 || mText.charAt(start - 1) == '\n'); if (isFirstParaLine) { final int spanEnd = sp.nextSpanTransition(start, mText.length(), ParagraphStyle.class); spans = getParagraphSpans(sp, start, spanEnd, ParagraphStyle.class); for (int n = spans.length - 1; n >= 0; n--) { if (spans[n] instanceof AlignmentSpan) { paraAlign = ((AlignmentSpan) spans[n]).getAlignment(); break; } } } final int length = spans.length; boolean useFirstLineMargin = isFirstParaLine; for (int n = 0; n < length; n++) { if (spans[n] instanceof LeadingMarginSpan2) { int count = ((LeadingMarginSpan2) spans[n]).getLeadingMarginLineCount(); int startLine = getLineForOffset(sp.getSpanStart(spans[n])); if (lineNum < startLine + count) { useFirstLineMargin = true; break; } } } for (int n = 0; n < length; n++) { if (spans[n] instanceof LeadingMarginSpan) { LeadingMarginSpan margin = (LeadingMarginSpan) spans[n]; if (dir == DIR_RIGHT_TO_LEFT) { right -= margin.getLeadingMargin(useFirstLineMargin); } else { left += margin.getLeadingMargin(useFirstLineMargin); } } } } final Alignment align; if (paraAlign == Alignment.ALIGN_LEFT) { align = (dir == DIR_LEFT_TO_RIGHT) ? Alignment.ALIGN_NORMAL : Alignment.ALIGN_OPPOSITE; } else if (paraAlign == Alignment.ALIGN_RIGHT) { align = (dir == DIR_LEFT_TO_RIGHT) ? Alignment.ALIGN_OPPOSITE : Alignment.ALIGN_NORMAL; } else { align = paraAlign; } final int indentWidth; if (align == Alignment.ALIGN_NORMAL) { if (dir == DIR_LEFT_TO_RIGHT) { indentWidth = getIndentAdjust(lineNum, Alignment.ALIGN_LEFT); } else { indentWidth = -getIndentAdjust(lineNum, Alignment.ALIGN_RIGHT); } } else if (align == Alignment.ALIGN_OPPOSITE) { if (dir == DIR_LEFT_TO_RIGHT) { indentWidth = -getIndentAdjust(lineNum, Alignment.ALIGN_RIGHT); } else { indentWidth = getIndentAdjust(lineNum, Alignment.ALIGN_LEFT); } } else { // Alignment.ALIGN_CENTER indentWidth = getIndentAdjust(lineNum, Alignment.ALIGN_CENTER); } return right - left - indentWidth; } /** * @hide */ @UnsupportedAppUsage public void drawText(Canvas canvas, int firstLine, int lastLine) { int previousLineBottom = getLineTop(firstLine); int previousLineEnd = getLineStart(firstLine); ParagraphStyle[] spans = NO_PARA_SPANS; int spanEnd = 0; final TextPaint paint = mWorkPaint; paint.set(mPaint); CharSequence buf = mText; Alignment paraAlign = mAlignment; TabStops tabStops = null; boolean tabStopsIsInitialized = false; TextLine tl = TextLine.obtain(); // Draw the lines, one at a time. // The baseline is the top of the following line minus the current line's descent. for (int lineNum = firstLine; lineNum <= lastLine; lineNum++) { int start = previousLineEnd; previousLineEnd = getLineStart(lineNum + 1); final boolean justify = isJustificationRequired(lineNum); int end = getLineVisibleEnd(lineNum, start, previousLineEnd); paint.setHyphenEdit(getHyphen(lineNum)); int ltop = previousLineBottom; int lbottom = getLineTop(lineNum + 1); previousLineBottom = lbottom; int lbaseline = lbottom - getLineDescent(lineNum); int dir = getParagraphDirection(lineNum); int left = 0; int right = mWidth; if (mSpannedText) { Spanned sp = (Spanned) buf; int textLength = buf.length(); boolean isFirstParaLine = (start == 0 || buf.charAt(start - 1) == '\n'); // New batch of paragraph styles, collect into spans array. // Compute the alignment, last alignment style wins. // Reset tabStops, we'll rebuild if we encounter a line with // tabs. // We expect paragraph spans to be relatively infrequent, use // spanEnd so that we can check less frequently. Since // paragraph styles ought to apply to entire paragraphs, we can // just collect the ones present at the start of the paragraph. // If spanEnd is before the end of the paragraph, that's not // our problem. if (start >= spanEnd && (lineNum == firstLine || isFirstParaLine)) { spanEnd = sp.nextSpanTransition(start, textLength, ParagraphStyle.class); spans = getParagraphSpans(sp, start, spanEnd, ParagraphStyle.class); paraAlign = mAlignment; for (int n = spans.length - 1; n >= 0; n--) { if (spans[n] instanceof AlignmentSpan) { paraAlign = ((AlignmentSpan) spans[n]).getAlignment(); break; } } tabStopsIsInitialized = false; } // Draw all leading margin spans. Adjust left or right according // to the paragraph direction of the line. final int length = spans.length; boolean useFirstLineMargin = isFirstParaLine; for (int n = 0; n < length; n++) { if (spans[n] instanceof LeadingMarginSpan2) { int count = ((LeadingMarginSpan2) spans[n]).getLeadingMarginLineCount(); int startLine = getLineForOffset(sp.getSpanStart(spans[n])); // if there is more than one LeadingMarginSpan2, use // the count that is greatest if (lineNum < startLine + count) { useFirstLineMargin = true; break; } } } for (int n = 0; n < length; n++) { if (spans[n] instanceof LeadingMarginSpan) { LeadingMarginSpan margin = (LeadingMarginSpan) spans[n]; if (dir == DIR_RIGHT_TO_LEFT) { margin.drawLeadingMargin(canvas, paint, right, dir, ltop, lbaseline, lbottom, buf, start, end, isFirstParaLine, this); right -= margin.getLeadingMargin(useFirstLineMargin); } else { margin.drawLeadingMargin(canvas, paint, left, dir, ltop, lbaseline, lbottom, buf, start, end, isFirstParaLine, this); left += margin.getLeadingMargin(useFirstLineMargin); } } } } boolean hasTab = getLineContainsTab(lineNum); // Can't tell if we have tabs for sure, currently if (hasTab && !tabStopsIsInitialized) { if (tabStops == null) { tabStops = new TabStops(TAB_INCREMENT, spans); } else { tabStops.reset(TAB_INCREMENT, spans); } tabStopsIsInitialized = true; } // Determine whether the line aligns to normal, opposite, or center. Alignment align = paraAlign; if (align == Alignment.ALIGN_LEFT) { align = (dir == DIR_LEFT_TO_RIGHT) ? Alignment.ALIGN_NORMAL : Alignment.ALIGN_OPPOSITE; } else if (align == Alignment.ALIGN_RIGHT) { align = (dir == DIR_LEFT_TO_RIGHT) ? Alignment.ALIGN_OPPOSITE : Alignment.ALIGN_NORMAL; } int x; final int indentWidth; if (align == Alignment.ALIGN_NORMAL) { if (dir == DIR_LEFT_TO_RIGHT) { indentWidth = getIndentAdjust(lineNum, Alignment.ALIGN_LEFT); x = left + indentWidth; } else { indentWidth = -getIndentAdjust(lineNum, Alignment.ALIGN_RIGHT); x = right - indentWidth; } } else { int max = (int) getLineExtent(lineNum, tabStops, false); if (align == Alignment.ALIGN_OPPOSITE) { if (dir == DIR_LEFT_TO_RIGHT) { indentWidth = -getIndentAdjust(lineNum, Alignment.ALIGN_RIGHT); x = right - max - indentWidth; } else { indentWidth = getIndentAdjust(lineNum, Alignment.ALIGN_LEFT); x = left - max + indentWidth; } } else { // Alignment.ALIGN_CENTER indentWidth = getIndentAdjust(lineNum, Alignment.ALIGN_CENTER); max = max & ~1; x = ((right + left - max) >> 1) + indentWidth; } } Directions directions = getLineDirections(lineNum); if (directions == DIRS_ALL_LEFT_TO_RIGHT && !mSpannedText && !hasTab && !justify) { // XXX: assumes there's nothing additional to be done canvas.drawText(buf, start, end, x, lbaseline, paint); } else { tl.set(paint, buf, start, end, dir, directions, hasTab, tabStops); if (justify) { tl.justify(right - left - indentWidth); } tl.draw(canvas, x, ltop, lbaseline, lbottom); } } TextLine.recycle(tl); } /** * @hide */ @UnsupportedAppUsage public void drawBackground(Canvas canvas, Path highlight, Paint highlightPaint, int cursorOffsetVertical, int firstLine, int lastLine) { // First, draw LineBackgroundSpans. // LineBackgroundSpans know nothing about the alignment, margins, or // direction of the layout or line. XXX: Should they? // They are evaluated at each line. if (mSpannedText) { if (mLineBackgroundSpans == null) { mLineBackgroundSpans = new SpanSet<LineBackgroundSpan>(LineBackgroundSpan.class); } Spanned buffer = (Spanned) mText; int textLength = buffer.length(); mLineBackgroundSpans.init(buffer, 0, textLength); if (mLineBackgroundSpans.numberOfSpans > 0) { int previousLineBottom = getLineTop(firstLine); int previousLineEnd = getLineStart(firstLine); ParagraphStyle[] spans = NO_PARA_SPANS; int spansLength = 0; TextPaint paint = mPaint; int spanEnd = 0; final int width = mWidth; for (int i = firstLine; i <= lastLine; i++) { int start = previousLineEnd; int end = getLineStart(i + 1); previousLineEnd = end; int ltop = previousLineBottom; int lbottom = getLineTop(i + 1); previousLineBottom = lbottom; int lbaseline = lbottom - getLineDescent(i); if (start >= spanEnd) { // These should be infrequent, so we'll use this so that // we don't have to check as often. spanEnd = mLineBackgroundSpans.getNextTransition(start, textLength); // All LineBackgroundSpans on a line contribute to its background. spansLength = 0; // Duplication of the logic of getParagraphSpans if (start != end || start == 0) { // Equivalent to a getSpans(start, end), but filling the 'spans' local // array instead to reduce memory allocation for (int j = 0; j < mLineBackgroundSpans.numberOfSpans; j++) { // equal test is valid since both intervals are not empty by // construction if (mLineBackgroundSpans.spanStarts[j] >= end || mLineBackgroundSpans.spanEnds[j] <= start) continue; spans = GrowingArrayUtils.append(spans, spansLength, mLineBackgroundSpans.spans[j]); spansLength++; } } } for (int n = 0; n < spansLength; n++) { LineBackgroundSpan lineBackgroundSpan = (LineBackgroundSpan) spans[n]; lineBackgroundSpan.drawBackground(canvas, paint, 0, width, ltop, lbaseline, lbottom, buffer, start, end, i); } } } mLineBackgroundSpans.recycle(); } // There can be a highlight even without spans if we are drawing // a non-spanned transformation of a spanned editing buffer. if (highlight != null) { if (cursorOffsetVertical != 0) canvas.translate(0, cursorOffsetVertical); canvas.drawPath(highlight, highlightPaint); if (cursorOffsetVertical != 0) canvas.translate(0, -cursorOffsetVertical); } } /** * @param canvas * @return The range of lines that need to be drawn, possibly empty. * @hide */ @UnsupportedAppUsage public long getLineRangeForDraw(Canvas canvas) { int dtop, dbottom; synchronized (sTempRect) { if (!canvas.getClipBounds(sTempRect)) { // Negative range end used as a special flag return TextUtils.packRangeInLong(0, -1); } dtop = sTempRect.top; dbottom = sTempRect.bottom; } final int top = Math.max(dtop, 0); final int bottom = Math.min(getLineTop(getLineCount()), dbottom); if (top >= bottom) return TextUtils.packRangeInLong(0, -1); return TextUtils.packRangeInLong(getLineForVertical(top), getLineForVertical(bottom)); } /** * Return the start position of the line, given the left and right bounds * of the margins. * * @param line the line index * @param left the left bounds (0, or leading margin if ltr para) * @param right the right bounds (width, minus leading margin if rtl para) * @return the start position of the line (to right of line if rtl para) */ private int getLineStartPos(int line, int left, int right) { // Adjust the point at which to start rendering depending on the // alignment of the paragraph. Alignment align = getParagraphAlignment(line); int dir = getParagraphDirection(line); if (align == Alignment.ALIGN_LEFT) { align = (dir == DIR_LEFT_TO_RIGHT) ? Alignment.ALIGN_NORMAL : Alignment.ALIGN_OPPOSITE; } else if (align == Alignment.ALIGN_RIGHT) { align = (dir == DIR_LEFT_TO_RIGHT) ? Alignment.ALIGN_OPPOSITE : Alignment.ALIGN_NORMAL; } int x; if (align == Alignment.ALIGN_NORMAL) { if (dir == DIR_LEFT_TO_RIGHT) { x = left + getIndentAdjust(line, Alignment.ALIGN_LEFT); } else { x = right + getIndentAdjust(line, Alignment.ALIGN_RIGHT); } } else { TabStops tabStops = null; if (mSpannedText && getLineContainsTab(line)) { Spanned spanned = (Spanned) mText; int start = getLineStart(line); int spanEnd = spanned.nextSpanTransition(start, spanned.length(), TabStopSpan.class); TabStopSpan[] tabSpans = getParagraphSpans(spanned, start, spanEnd, TabStopSpan.class); if (tabSpans.length > 0) { tabStops = new TabStops(TAB_INCREMENT, tabSpans); } } int max = (int) getLineExtent(line, tabStops, false); if (align == Alignment.ALIGN_OPPOSITE) { if (dir == DIR_LEFT_TO_RIGHT) { x = right - max + getIndentAdjust(line, Alignment.ALIGN_RIGHT); } else { // max is negative here x = left - max + getIndentAdjust(line, Alignment.ALIGN_LEFT); } } else { // Alignment.ALIGN_CENTER max = max & ~1; x = (left + right - max) >> 1 + getIndentAdjust(line, Alignment.ALIGN_CENTER); } } return x; } /** * Return the text that is displayed by this Layout. */ public final CharSequence getText() { return mText; } /** * Return the base Paint properties for this layout. * Do NOT change the paint, which may result in funny * drawing for this layout. */ public final TextPaint getPaint() { return mPaint; } /** * Return the width of this layout. */ public final int getWidth() { return mWidth; } /** * Return the width to which this Layout is ellipsizing, or * {@link #getWidth} if it is not doing anything special. */ public int getEllipsizedWidth() { return mWidth; } /** * Increase the width of this layout to the specified width. * Be careful to use this only when you know it is appropriate— * it does not cause the text to reflow to use the full new width. */ public final void increaseWidthTo(int wid) { if (wid < mWidth) { throw new RuntimeException("attempted to reduce Layout width"); } mWidth = wid; } /** * Return the total height of this layout. */ public int getHeight() { return getLineTop(getLineCount()); } /** * Return the total height of this layout. * * @param cap if true and max lines is set, returns the height of the layout at the max lines. * * @hide */ public int getHeight(boolean cap) { return getHeight(); } /** * Return the base alignment of this layout. */ public final Alignment getAlignment() { return mAlignment; } /** * Return what the text height is multiplied by to get the line height. */ public final float getSpacingMultiplier() { return mSpacingMult; } /** * Return the number of units of leading that are added to each line. */ public final float getSpacingAdd() { return mSpacingAdd; } /** * Return the heuristic used to determine paragraph text direction. * @hide */ public final TextDirectionHeuristic getTextDirectionHeuristic() { return mTextDir; } /** * Return the number of lines of text in this layout. */ public abstract int getLineCount(); /** * Return the baseline for the specified line (0…getLineCount() - 1) * If bounds is not null, return the top, left, right, bottom extents * of the specified line in it. * @param line which line to examine (0..getLineCount() - 1) * @param bounds Optional. If not null, it returns the extent of the line * @return the Y-coordinate of the baseline */ public int getLineBounds(int line, Rect bounds) { if (bounds != null) { bounds.left = 0; // ??? bounds.top = getLineTop(line); bounds.right = mWidth; // ??? bounds.bottom = getLineTop(line + 1); } return getLineBaseline(line); } /** * Return the vertical position of the top of the specified line * (0…getLineCount()). * If the specified line is equal to the line count, returns the * bottom of the last line. */ public abstract int getLineTop(int line); /** * Return the descent of the specified line(0…getLineCount() - 1). */ public abstract int getLineDescent(int line); /** * Return the text offset of the beginning of the specified line ( * 0…getLineCount()). If the specified line is equal to the line * count, returns the length of the text. */ public abstract int getLineStart(int line); /** * Returns the primary directionality of the paragraph containing the * specified line, either 1 for left-to-right lines, or -1 for right-to-left * lines (see {@link #DIR_LEFT_TO_RIGHT}, {@link #DIR_RIGHT_TO_LEFT}). */ public abstract int getParagraphDirection(int line); /** * Returns whether the specified line contains one or more * characters that need to be handled specially, like tabs. */ public abstract boolean getLineContainsTab(int line); /** * Returns the directional run information for the specified line. * The array alternates counts of characters in left-to-right * and right-to-left segments of the line. * * <p>NOTE: this is inadequate to support bidirectional text, and will change. */ public abstract Directions getLineDirections(int line); /** * Returns the (negative) number of extra pixels of ascent padding in the * top line of the Layout. */ public abstract int getTopPadding(); /** * Returns the number of extra pixels of descent padding in the * bottom line of the Layout. */ public abstract int getBottomPadding(); /** * Returns the hyphen edit for a line. * * @hide */ public int getHyphen(int line) { return 0; } /** * Returns the left indent for a line. * * @hide */ public int getIndentAdjust(int line, Alignment alignment) { return 0; } /** * Returns true if the character at offset and the preceding character * are at different run levels (and thus there's a split caret). * @param offset the offset * @return true if at a level boundary * @hide */ @UnsupportedAppUsage public boolean isLevelBoundary(int offset) { int line = getLineForOffset(offset); Directions dirs = getLineDirections(line); if (dirs == DIRS_ALL_LEFT_TO_RIGHT || dirs == DIRS_ALL_RIGHT_TO_LEFT) { return false; } int[] runs = dirs.mDirections; int lineStart = getLineStart(line); int lineEnd = getLineEnd(line); if (offset == lineStart || offset == lineEnd) { int paraLevel = getParagraphDirection(line) == 1 ? 0 : 1; int runIndex = offset == lineStart ? 0 : runs.length - 2; return ((runs[runIndex + 1] >>> RUN_LEVEL_SHIFT) & RUN_LEVEL_MASK) != paraLevel; } offset -= lineStart; for (int i = 0; i < runs.length; i += 2) { if (offset == runs[i]) { return true; } } return false; } /** * Returns true if the character at offset is right to left (RTL). * @param offset the offset * @return true if the character is RTL, false if it is LTR */ public boolean isRtlCharAt(int offset) { int line = getLineForOffset(offset); Directions dirs = getLineDirections(line); if (dirs == DIRS_ALL_LEFT_TO_RIGHT) { return false; } if (dirs == DIRS_ALL_RIGHT_TO_LEFT) { return true; } int[] runs = dirs.mDirections; int lineStart = getLineStart(line); for (int i = 0; i < runs.length; i += 2) { int start = lineStart + runs[i]; int limit = start + (runs[i + 1] & RUN_LENGTH_MASK); if (offset >= start && offset < limit) { int level = (runs[i + 1] >>> RUN_LEVEL_SHIFT) & RUN_LEVEL_MASK; return ((level & 1) != 0); } } // Should happen only if the offset is "out of bounds" return false; } /** * Returns the range of the run that the character at offset belongs to. * @param offset the offset * @return The range of the run * @hide */ public long getRunRange(int offset) { int line = getLineForOffset(offset); Directions dirs = getLineDirections(line); if (dirs == DIRS_ALL_LEFT_TO_RIGHT || dirs == DIRS_ALL_RIGHT_TO_LEFT) { return TextUtils.packRangeInLong(0, getLineEnd(line)); } int[] runs = dirs.mDirections; int lineStart = getLineStart(line); for (int i = 0; i < runs.length; i += 2) { int start = lineStart + runs[i]; int limit = start + (runs[i + 1] & RUN_LENGTH_MASK); if (offset >= start && offset < limit) { return TextUtils.packRangeInLong(start, limit); } } // Should happen only if the offset is "out of bounds" return TextUtils.packRangeInLong(0, getLineEnd(line)); } /** * Checks if the trailing BiDi level should be used for an offset * * This method is useful when the offset is at the BiDi level transition point and determine * which run need to be used. For example, let's think about following input: (L* denotes * Left-to-Right characters, R* denotes Right-to-Left characters.) * Input (Logical Order): L1 L2 L3 R1 R2 R3 L4 L5 L6 * Input (Display Order): L1 L2 L3 R3 R2 R1 L4 L5 L6 * * Then, think about selecting the range (3, 6). The offset=3 and offset=6 are ambiguous here * since they are at the BiDi transition point. In Android, the offset is considered to be * associated with the trailing run if the BiDi level of the trailing run is higher than of the * previous run. In this case, the BiDi level of the input text is as follows: * * Input (Logical Order): L1 L2 L3 R1 R2 R3 L4 L5 L6 * BiDi Run: [ Run 0 ][ Run 1 ][ Run 2 ] * BiDi Level: 0 0 0 1 1 1 0 0 0 * * Thus, offset = 3 is part of Run 1 and this method returns true for offset = 3, since the BiDi * level of Run 1 is higher than the level of Run 0. Similarly, the offset = 6 is a part of Run * 1 and this method returns false for the offset = 6 since the BiDi level of Run 1 is higher * than the level of Run 2. * * @returns true if offset is at the BiDi level transition point and trailing BiDi level is * higher than previous BiDi level. See above for the detail. */ private boolean primaryIsTrailingPrevious(int offset) { int line = getLineForOffset(offset); int lineStart = getLineStart(line); int lineEnd = getLineEnd(line); int[] runs = getLineDirections(line).mDirections; int levelAt = -1; for (int i = 0; i < runs.length; i += 2) { int start = lineStart + runs[i]; int limit = start + (runs[i + 1] & RUN_LENGTH_MASK); if (limit > lineEnd) { limit = lineEnd; } if (offset >= start && offset < limit) { if (offset > start) { // Previous character is at same level, so don't use trailing. return false; } levelAt = (runs[i + 1] >>> RUN_LEVEL_SHIFT) & RUN_LEVEL_MASK; break; } } if (levelAt == -1) { // Offset was limit of line. levelAt = getParagraphDirection(line) == 1 ? 0 : 1; } // At level boundary, check previous level. int levelBefore = -1; if (offset == lineStart) { levelBefore = getParagraphDirection(line) == 1 ? 0 : 1; } else { offset -= 1; for (int i = 0; i < runs.length; i += 2) { int start = lineStart + runs[i]; int limit = start + (runs[i + 1] & RUN_LENGTH_MASK); if (limit > lineEnd) { limit = lineEnd; } if (offset >= start && offset < limit) { levelBefore = (runs[i + 1] >>> RUN_LEVEL_SHIFT) & RUN_LEVEL_MASK; break; } } } return levelBefore < levelAt; } /** * Computes in linear time the results of calling * #primaryIsTrailingPrevious for all offsets on a line. * @param line The line giving the offsets we compute the information for * @return The array of results, indexed from 0, where 0 corresponds to the line start offset */ private boolean[] primaryIsTrailingPreviousAllLineOffsets(int line) { int lineStart = getLineStart(line); int lineEnd = getLineEnd(line); int[] runs = getLineDirections(line).mDirections; boolean[] trailing = new boolean[lineEnd - lineStart + 1]; byte[] level = new byte[lineEnd - lineStart + 1]; for (int i = 0; i < runs.length; i += 2) { int start = lineStart + runs[i]; int limit = start + (runs[i + 1] & RUN_LENGTH_MASK); if (limit > lineEnd) { limit = lineEnd; } level[limit - lineStart - 1] = (byte) ((runs[i + 1] >>> RUN_LEVEL_SHIFT) & RUN_LEVEL_MASK); } for (int i = 0; i < runs.length; i += 2) { int start = lineStart + runs[i]; byte currentLevel = (byte) ((runs[i + 1] >>> RUN_LEVEL_SHIFT) & RUN_LEVEL_MASK); trailing[start - lineStart] = currentLevel > (start == lineStart ? (getParagraphDirection(line) == 1 ? 0 : 1) : level[start - lineStart - 1]); } return trailing; } /** * Get the primary horizontal position for the specified text offset. * This is the location where a new character would be inserted in * the paragraph's primary direction. */ public float getPrimaryHorizontal(int offset) { return getPrimaryHorizontal(offset, false /* not clamped */); } /** * Get the primary horizontal position for the specified text offset, but * optionally clamp it so that it doesn't exceed the width of the layout. * @hide */ @UnsupportedAppUsage public float getPrimaryHorizontal(int offset, boolean clamped) { boolean trailing = primaryIsTrailingPrevious(offset); return getHorizontal(offset, trailing, clamped); } /** * Get the secondary horizontal position for the specified text offset. * This is the location where a new character would be inserted in * the direction other than the paragraph's primary direction. */ public float getSecondaryHorizontal(int offset) { return getSecondaryHorizontal(offset, false /* not clamped */); } /** * Get the secondary horizontal position for the specified text offset, but * optionally clamp it so that it doesn't exceed the width of the layout. * @hide */ @UnsupportedAppUsage public float getSecondaryHorizontal(int offset, boolean clamped) { boolean trailing = primaryIsTrailingPrevious(offset); return getHorizontal(offset, !trailing, clamped); } private float getHorizontal(int offset, boolean primary) { return primary ? getPrimaryHorizontal(offset) : getSecondaryHorizontal(offset); } private float getHorizontal(int offset, boolean trailing, boolean clamped) { int line = getLineForOffset(offset); return getHorizontal(offset, trailing, line, clamped); } private float getHorizontal(int offset, boolean trailing, int line, boolean clamped) { int start = getLineStart(line); int end = getLineEnd(line); int dir = getParagraphDirection(line); boolean hasTab = getLineContainsTab(line); Directions directions = getLineDirections(line); TabStops tabStops = null; if (hasTab && mText instanceof Spanned) { // Just checking this line should be good enough, tabs should be // consistent across all lines in a paragraph. TabStopSpan[] tabs = getParagraphSpans((Spanned) mText, start, end, TabStopSpan.class); if (tabs.length > 0) { tabStops = new TabStops(TAB_INCREMENT, tabs); // XXX should reuse } } TextLine tl = TextLine.obtain(); tl.set(mPaint, mText, start, end, dir, directions, hasTab, tabStops); float wid = tl.measure(offset - start, trailing, null); TextLine.recycle(tl); if (clamped && wid > mWidth) { wid = mWidth; } int left = getParagraphLeft(line); int right = getParagraphRight(line); return getLineStartPos(line, left, right) + wid; } /** * Computes in linear time the results of calling * #getHorizontal for all offsets on a line. * @param line The line giving the offsets we compute information for * @param clamped Whether to clamp the results to the width of the layout * @param primary Whether the results should be the primary or the secondary horizontal * @return The array of results, indexed from 0, where 0 corresponds to the line start offset */ private float[] getLineHorizontals(int line, boolean clamped, boolean primary) { int start = getLineStart(line); int end = getLineEnd(line); int dir = getParagraphDirection(line); boolean hasTab = getLineContainsTab(line); Directions directions = getLineDirections(line); TabStops tabStops = null; if (hasTab && mText instanceof Spanned) { // Just checking this line should be good enough, tabs should be // consistent across all lines in a paragraph. TabStopSpan[] tabs = getParagraphSpans((Spanned) mText, start, end, TabStopSpan.class); if (tabs.length > 0) { tabStops = new TabStops(TAB_INCREMENT, tabs); // XXX should reuse } } TextLine tl = TextLine.obtain(); tl.set(mPaint, mText, start, end, dir, directions, hasTab, tabStops); boolean[] trailings = primaryIsTrailingPreviousAllLineOffsets(line); if (!primary) { for (int offset = 0; offset < trailings.length; ++offset) { trailings[offset] = !trailings[offset]; } } float[] wid = tl.measureAllOffsets(trailings, null); TextLine.recycle(tl); if (clamped) { for (int offset = 0; offset <= wid.length; ++offset) { if (wid[offset] > mWidth) { wid[offset] = mWidth; } } } int left = getParagraphLeft(line); int right = getParagraphRight(line); int lineStartPos = getLineStartPos(line, left, right); float[] horizontal = new float[end - start + 1]; for (int offset = 0; offset < horizontal.length; ++offset) { horizontal[offset] = lineStartPos + wid[offset]; } return horizontal; } /** * Get the leftmost position that should be exposed for horizontal * scrolling on the specified line. */ public float getLineLeft(int line) { int dir = getParagraphDirection(line); Alignment align = getParagraphAlignment(line); if (align == Alignment.ALIGN_LEFT) { return 0; } else if (align == Alignment.ALIGN_NORMAL) { if (dir == DIR_RIGHT_TO_LEFT) return getParagraphRight(line) - getLineMax(line); else return 0; } else if (align == Alignment.ALIGN_RIGHT) { return mWidth - getLineMax(line); } else if (align == Alignment.ALIGN_OPPOSITE) { if (dir == DIR_RIGHT_TO_LEFT) return 0; else return mWidth - getLineMax(line); } else { /* align == Alignment.ALIGN_CENTER */ int left = getParagraphLeft(line); int right = getParagraphRight(line); int max = ((int) getLineMax(line)) & ~1; return left + ((right - left) - max) / 2; } } /** * Get the rightmost position that should be exposed for horizontal * scrolling on the specified line. */ public float getLineRight(int line) { int dir = getParagraphDirection(line); Alignment align = getParagraphAlignment(line); if (align == Alignment.ALIGN_LEFT) { return getParagraphLeft(line) + getLineMax(line); } else if (align == Alignment.ALIGN_NORMAL) { if (dir == DIR_RIGHT_TO_LEFT) return mWidth; else return getParagraphLeft(line) + getLineMax(line); } else if (align == Alignment.ALIGN_RIGHT) { return mWidth; } else if (align == Alignment.ALIGN_OPPOSITE) { if (dir == DIR_RIGHT_TO_LEFT) return getLineMax(line); else return mWidth; } else { /* align == Alignment.ALIGN_CENTER */ int left = getParagraphLeft(line); int right = getParagraphRight(line); int max = ((int) getLineMax(line)) & ~1; return right - ((right - left) - max) / 2; } } /** * Gets the unsigned horizontal extent of the specified line, including * leading margin indent, but excluding trailing whitespace. */ public float getLineMax(int line) { float margin = getParagraphLeadingMargin(line); float signedExtent = getLineExtent(line, false); return margin + (signedExtent >= 0 ? signedExtent : -signedExtent); } /** * Gets the unsigned horizontal extent of the specified line, including * leading margin indent and trailing whitespace. */ public float getLineWidth(int line) { float margin = getParagraphLeadingMargin(line); float signedExtent = getLineExtent(line, true); return margin + (signedExtent >= 0 ? signedExtent : -signedExtent); } /** * Like {@link #getLineExtent(int,TabStops,boolean)} but determines the * tab stops instead of using the ones passed in. * @param line the index of the line * @param full whether to include trailing whitespace * @return the extent of the line */ private float getLineExtent(int line, boolean full) { final int start = getLineStart(line); final int end = full ? getLineEnd(line) : getLineVisibleEnd(line); final boolean hasTabs = getLineContainsTab(line); TabStops tabStops = null; if (hasTabs && mText instanceof Spanned) { // Just checking this line should be good enough, tabs should be // consistent across all lines in a paragraph. TabStopSpan[] tabs = getParagraphSpans((Spanned) mText, start, end, TabStopSpan.class); if (tabs.length > 0) { tabStops = new TabStops(TAB_INCREMENT, tabs); // XXX should reuse } } final Directions directions = getLineDirections(line); // Returned directions can actually be null if (directions == null) { return 0f; } final int dir = getParagraphDirection(line); final TextLine tl = TextLine.obtain(); final TextPaint paint = mWorkPaint; paint.set(mPaint); paint.setHyphenEdit(getHyphen(line)); tl.set(paint, mText, start, end, dir, directions, hasTabs, tabStops); if (isJustificationRequired(line)) { tl.justify(getJustifyWidth(line)); } final float width = tl.metrics(null); TextLine.recycle(tl); return width; } /** * Returns the signed horizontal extent of the specified line, excluding * leading margin. If full is false, excludes trailing whitespace. * @param line the index of the line * @param tabStops the tab stops, can be null if we know they're not used. * @param full whether to include trailing whitespace * @return the extent of the text on this line */ private float getLineExtent(int line, TabStops tabStops, boolean full) { final int start = getLineStart(line); final int end = full ? getLineEnd(line) : getLineVisibleEnd(line); final boolean hasTabs = getLineContainsTab(line); final Directions directions = getLineDirections(line); final int dir = getParagraphDirection(line); final TextLine tl = TextLine.obtain(); final TextPaint paint = mWorkPaint; paint.set(mPaint); paint.setHyphenEdit(getHyphen(line)); tl.set(paint, mText, start, end, dir, directions, hasTabs, tabStops); if (isJustificationRequired(line)) { tl.justify(getJustifyWidth(line)); } final float width = tl.metrics(null); TextLine.recycle(tl); return width; } /** * Get the line number corresponding to the specified vertical position. * If you ask for a position above 0, you get 0; if you ask for a position * below the bottom of the text, you get the last line. */ // FIXME: It may be faster to do a linear search for layouts without many lines. public int getLineForVertical(int vertical) { int high = getLineCount(), low = -1, guess; while (high - low > 1) { guess = (high + low) / 2; if (getLineTop(guess) > vertical) high = guess; else low = guess; } if (low < 0) return 0; else return low; } /** * Get the line number on which the specified text offset appears. * If you ask for a position before 0, you get 0; if you ask for a position * beyond the end of the text, you get the last line. */ public int getLineForOffset(int offset) { int high = getLineCount(), low = -1, guess; while (high - low > 1) { guess = (high + low) / 2; if (getLineStart(guess) > offset) high = guess; else low = guess; } if (low < 0) { return 0; } else { return low; } } /** * Get the character offset on the specified line whose position is * closest to the specified horizontal position. */ public int getOffsetForHorizontal(int line, float horiz) { return getOffsetForHorizontal(line, horiz, true); } /** * Get the character offset on the specified line whose position is * closest to the specified horizontal position. * * @param line the line used to find the closest offset * @param horiz the horizontal position used to find the closest offset * @param primary whether to use the primary position or secondary position to find the offset * * @hide */ public int getOffsetForHorizontal(int line, float horiz, boolean primary) { // TODO: use Paint.getOffsetForAdvance to avoid binary search final int lineEndOffset = getLineEnd(line); final int lineStartOffset = getLineStart(line); Directions dirs = getLineDirections(line); TextLine tl = TextLine.obtain(); // XXX: we don't care about tabs as we just use TextLine#getOffsetToLeftRightOf here. tl.set(mPaint, mText, lineStartOffset, lineEndOffset, getParagraphDirection(line), dirs, false, null); final HorizontalMeasurementProvider horizontal = new HorizontalMeasurementProvider(line, primary); final int max; if (line == getLineCount() - 1) { max = lineEndOffset; } else { max = tl.getOffsetToLeftRightOf(lineEndOffset - lineStartOffset, !isRtlCharAt(lineEndOffset - 1)) + lineStartOffset; } int best = lineStartOffset; float bestdist = Math.abs(horizontal.get(lineStartOffset) - horiz); for (int i = 0; i < dirs.mDirections.length; i += 2) { int here = lineStartOffset + dirs.mDirections[i]; int there = here + (dirs.mDirections[i + 1] & RUN_LENGTH_MASK); boolean isRtl = (dirs.mDirections[i + 1] & RUN_RTL_FLAG) != 0; int swap = isRtl ? -1 : 1; if (there > max) there = max; int high = there - 1 + 1, low = here + 1 - 1, guess; while (high - low > 1) { guess = (high + low) / 2; int adguess = getOffsetAtStartOf(guess); if (horizontal.get(adguess) * swap >= horiz * swap) { high = guess; } else { low = guess; } } if (low < here + 1) low = here + 1; if (low < there) { int aft = tl.getOffsetToLeftRightOf(low - lineStartOffset, isRtl) + lineStartOffset; low = tl.getOffsetToLeftRightOf(aft - lineStartOffset, !isRtl) + lineStartOffset; if (low >= here && low < there) { float dist = Math.abs(horizontal.get(low) - horiz); if (aft < there) { float other = Math.abs(horizontal.get(aft) - horiz); if (other < dist) { dist = other; low = aft; } } if (dist < bestdist) { bestdist = dist; best = low; } } } float dist = Math.abs(horizontal.get(here) - horiz); if (dist < bestdist) { bestdist = dist; best = here; } } float dist = Math.abs(horizontal.get(max) - horiz); if (dist <= bestdist) { best = max; } TextLine.recycle(tl); return best; } /** * Responds to #getHorizontal queries, by selecting the better strategy between: * - calling #getHorizontal explicitly for each query * - precomputing all #getHorizontal measurements, and responding to any query in constant time * The first strategy is used for LTR-only text, while the second is used for all other cases. * The class is currently only used in #getOffsetForHorizontal, so reuse with care in other * contexts. */ private class HorizontalMeasurementProvider { private final int mLine; private final boolean mPrimary; private float[] mHorizontals; private int mLineStartOffset; HorizontalMeasurementProvider(final int line, final boolean primary) { mLine = line; mPrimary = primary; init(); } private void init() { final Directions dirs = getLineDirections(mLine); if (dirs == DIRS_ALL_LEFT_TO_RIGHT) { return; } mHorizontals = getLineHorizontals(mLine, false, mPrimary); mLineStartOffset = getLineStart(mLine); } float get(final int offset) { if (mHorizontals == null || offset < mLineStartOffset || offset >= mLineStartOffset + mHorizontals.length) { return getHorizontal(offset, mPrimary); } else { return mHorizontals[offset - mLineStartOffset]; } } } /** * Return the text offset after the last character on the specified line. */ public final int getLineEnd(int line) { return getLineStart(line + 1); } /** * Return the text offset after the last visible character (so whitespace * is not counted) on the specified line. */ public int getLineVisibleEnd(int line) { return getLineVisibleEnd(line, getLineStart(line), getLineStart(line + 1)); } private int getLineVisibleEnd(int line, int start, int end) { CharSequence text = mText; char ch; if (line == getLineCount() - 1) { return end; } for (; end > start; end--) { ch = text.charAt(end - 1); if (ch == '\n') { return end - 1; } if (!TextLine.isLineEndSpace(ch)) { break; } } return end; } /** * Return the vertical position of the bottom of the specified line. */ public final int getLineBottom(int line) { return getLineTop(line + 1); } /** * Return the vertical position of the bottom of the specified line without the line spacing * added. * * @hide */ public final int getLineBottomWithoutSpacing(int line) { return getLineTop(line + 1) - getLineExtra(line); } /** * Return the vertical position of the baseline of the specified line. */ public final int getLineBaseline(int line) { // getLineTop(line+1) == getLineTop(line) return getLineTop(line + 1) - getLineDescent(line); } /** * Get the ascent of the text on the specified line. * The return value is negative to match the Paint.ascent() convention. */ public final int getLineAscent(int line) { // getLineTop(line+1) - getLineDescent(line) == getLineBaseLine(line) return getLineTop(line) - (getLineTop(line + 1) - getLineDescent(line)); } /** * Return the extra space added as a result of line spacing attributes * {@link #getSpacingAdd()} and {@link #getSpacingMultiplier()}. Default value is {@code zero}. * * @param line the index of the line, the value should be equal or greater than {@code zero} * @hide */ public int getLineExtra(@IntRange(from = 0) int line) { return 0; } public int getOffsetToLeftOf(int offset) { return getOffsetToLeftRightOf(offset, true); } public int getOffsetToRightOf(int offset) { return getOffsetToLeftRightOf(offset, false); } private int getOffsetToLeftRightOf(int caret, boolean toLeft) { int line = getLineForOffset(caret); int lineStart = getLineStart(line); int lineEnd = getLineEnd(line); int lineDir = getParagraphDirection(line); boolean lineChanged = false; boolean advance = toLeft == (lineDir == DIR_RIGHT_TO_LEFT); // if walking off line, look at the line we're headed to if (advance) { if (caret == lineEnd) { if (line < getLineCount() - 1) { lineChanged = true; ++line; } else { return caret; // at very end, don't move } } } else { if (caret == lineStart) { if (line > 0) { lineChanged = true; --line; } else { return caret; // at very start, don't move } } } if (lineChanged) { lineStart = getLineStart(line); lineEnd = getLineEnd(line); int newDir = getParagraphDirection(line); if (newDir != lineDir) { // unusual case. we want to walk onto the line, but it runs // in a different direction than this one, so we fake movement // in the opposite direction. toLeft = !toLeft; lineDir = newDir; } } Directions directions = getLineDirections(line); TextLine tl = TextLine.obtain(); // XXX: we don't care about tabs tl.set(mPaint, mText, lineStart, lineEnd, lineDir, directions, false, null); caret = lineStart + tl.getOffsetToLeftRightOf(caret - lineStart, toLeft); TextLine.recycle(tl); return caret; } private int getOffsetAtStartOf(int offset) { // XXX this probably should skip local reorderings and // zero-width characters, look at callers if (offset == 0) return 0; CharSequence text = mText; char c = text.charAt(offset); if (c >= '\uDC00' && c <= '\uDFFF') { char c1 = text.charAt(offset - 1); if (c1 >= '\uD800' && c1 <= '\uDBFF') offset -= 1; } if (mSpannedText) { ReplacementSpan[] spans = ((Spanned) text).getSpans(offset, offset, ReplacementSpan.class); for (int i = 0; i < spans.length; i++) { int start = ((Spanned) text).getSpanStart(spans[i]); int end = ((Spanned) text).getSpanEnd(spans[i]); if (start < offset && end > offset) offset = start; } } return offset; } /** * Determine whether we should clamp cursor position. Currently it's * only robust for left-aligned displays. * @hide */ @UnsupportedAppUsage public boolean shouldClampCursor(int line) { // Only clamp cursor position in left-aligned displays. switch (getParagraphAlignment(line)) { case ALIGN_LEFT: return true; case ALIGN_NORMAL: return getParagraphDirection(line) > 0; default: return false; } } /** * Fills in the specified Path with a representation of a cursor * at the specified offset. This will often be a vertical line * but can be multiple discontinuous lines in text with multiple * directionalities. */ public void getCursorPath(final int point, final Path dest, final CharSequence editingBuffer) { dest.reset(); int line = getLineForOffset(point); int top = getLineTop(line); int bottom = getLineBottomWithoutSpacing(line); boolean clamped = shouldClampCursor(line); float h1 = getPrimaryHorizontal(point, clamped) - 0.5f; float h2 = isLevelBoundary(point) ? getSecondaryHorizontal(point, clamped) - 0.5f : h1; int caps = TextKeyListener.getMetaState(editingBuffer, TextKeyListener.META_SHIFT_ON) | TextKeyListener.getMetaState(editingBuffer, TextKeyListener.META_SELECTING); int fn = TextKeyListener.getMetaState(editingBuffer, TextKeyListener.META_ALT_ON); int dist = 0; if (caps != 0 || fn != 0) { dist = (bottom - top) >> 2; if (fn != 0) top += dist; if (caps != 0) bottom -= dist; } if (h1 < 0.5f) h1 = 0.5f; if (h2 < 0.5f) h2 = 0.5f; if (Float.compare(h1, h2) == 0) { dest.moveTo(h1, top); dest.lineTo(h1, bottom); } else { dest.moveTo(h1, top); dest.lineTo(h1, (top + bottom) >> 1); dest.moveTo(h2, (top + bottom) >> 1); dest.lineTo(h2, bottom); } if (caps == 2) { dest.moveTo(h2, bottom); dest.lineTo(h2 - dist, bottom + dist); dest.lineTo(h2, bottom); dest.lineTo(h2 + dist, bottom + dist); } else if (caps == 1) { dest.moveTo(h2, bottom); dest.lineTo(h2 - dist, bottom + dist); dest.moveTo(h2 - dist, bottom + dist - 0.5f); dest.lineTo(h2 + dist, bottom + dist - 0.5f); dest.moveTo(h2 + dist, bottom + dist); dest.lineTo(h2, bottom); } if (fn == 2) { dest.moveTo(h1, top); dest.lineTo(h1 - dist, top - dist); dest.lineTo(h1, top); dest.lineTo(h1 + dist, top - dist); } else if (fn == 1) { dest.moveTo(h1, top); dest.lineTo(h1 - dist, top - dist); dest.moveTo(h1 - dist, top - dist + 0.5f); dest.lineTo(h1 + dist, top - dist + 0.5f); dest.moveTo(h1 + dist, top - dist); dest.lineTo(h1, top); } } private void addSelection(int line, int start, int end, int top, int bottom, SelectionRectangleConsumer consumer) { int linestart = getLineStart(line); int lineend = getLineEnd(line); Directions dirs = getLineDirections(line); if (lineend > linestart && mText.charAt(lineend - 1) == '\n') { lineend--; } for (int i = 0; i < dirs.mDirections.length; i += 2) { int here = linestart + dirs.mDirections[i]; int there = here + (dirs.mDirections[i + 1] & RUN_LENGTH_MASK); if (there > lineend) { there = lineend; } if (start <= there && end >= here) { int st = Math.max(start, here); int en = Math.min(end, there); if (st != en) { float h1 = getHorizontal(st, false, line, false /* not clamped */); float h2 = getHorizontal(en, true, line, false /* not clamped */); float left = Math.min(h1, h2); float right = Math.max(h1, h2); final @TextSelectionLayout int layout = ((dirs.mDirections[i + 1] & RUN_RTL_FLAG) != 0) ? TEXT_SELECTION_LAYOUT_RIGHT_TO_LEFT : TEXT_SELECTION_LAYOUT_LEFT_TO_RIGHT; consumer.accept(left, top, right, bottom, layout); } } } } /** * Fills in the specified Path with a representation of a highlight * between the specified offsets. This will often be a rectangle * or a potentially discontinuous set of rectangles. If the start * and end are the same, the returned path is empty. */ public void getSelectionPath(int start, int end, Path dest) { dest.reset(); getSelection(start, end, (left, top, right, bottom, textSelectionLayout) -> dest.addRect(left, top, right, bottom, Path.Direction.CW)); } /** * Calculates the rectangles which should be highlighted to indicate a selection between start * and end and feeds them into the given {@link SelectionRectangleConsumer}. * * @param start the starting index of the selection * @param end the ending index of the selection * @param consumer the {@link SelectionRectangleConsumer} which will receive the generated * rectangles. It will be called every time a rectangle is generated. * @hide * @see #getSelectionPath(int, int, Path) */ public final void getSelection(int start, int end, final SelectionRectangleConsumer consumer) { if (start == end) { return; } if (end < start) { int temp = end; end = start; start = temp; } final int startline = getLineForOffset(start); final int endline = getLineForOffset(end); int top = getLineTop(startline); int bottom = getLineBottomWithoutSpacing(endline); if (startline == endline) { addSelection(startline, start, end, top, bottom, consumer); } else { final float width = mWidth; addSelection(startline, start, getLineEnd(startline), top, getLineBottom(startline), consumer); if (getParagraphDirection(startline) == DIR_RIGHT_TO_LEFT) { consumer.accept(getLineLeft(startline), top, 0, getLineBottom(startline), TEXT_SELECTION_LAYOUT_RIGHT_TO_LEFT); } else { consumer.accept(getLineRight(startline), top, width, getLineBottom(startline), TEXT_SELECTION_LAYOUT_LEFT_TO_RIGHT); } for (int i = startline + 1; i < endline; i++) { top = getLineTop(i); bottom = getLineBottom(i); if (getParagraphDirection(i) == DIR_RIGHT_TO_LEFT) { consumer.accept(0, top, width, bottom, TEXT_SELECTION_LAYOUT_RIGHT_TO_LEFT); } else { consumer.accept(0, top, width, bottom, TEXT_SELECTION_LAYOUT_LEFT_TO_RIGHT); } } top = getLineTop(endline); bottom = getLineBottomWithoutSpacing(endline); addSelection(endline, getLineStart(endline), end, top, bottom, consumer); if (getParagraphDirection(endline) == DIR_RIGHT_TO_LEFT) { consumer.accept(width, top, getLineRight(endline), bottom, TEXT_SELECTION_LAYOUT_RIGHT_TO_LEFT); } else { consumer.accept(0, top, getLineLeft(endline), bottom, TEXT_SELECTION_LAYOUT_LEFT_TO_RIGHT); } } } /** * Get the alignment of the specified paragraph, taking into account * markup attached to it. */ public final Alignment getParagraphAlignment(int line) { Alignment align = mAlignment; if (mSpannedText) { Spanned sp = (Spanned) mText; AlignmentSpan[] spans = getParagraphSpans(sp, getLineStart(line), getLineEnd(line), AlignmentSpan.class); int spanLength = spans.length; if (spanLength > 0) { align = spans[spanLength - 1].getAlignment(); } } return align; } /** * Get the left edge of the specified paragraph, inset by left margins. */ public final int getParagraphLeft(int line) { int left = 0; int dir = getParagraphDirection(line); if (dir == DIR_RIGHT_TO_LEFT || !mSpannedText) { return left; // leading margin has no impact, or no styles } return getParagraphLeadingMargin(line); } /** * Get the right edge of the specified paragraph, inset by right margins. */ public final int getParagraphRight(int line) { int right = mWidth; int dir = getParagraphDirection(line); if (dir == DIR_LEFT_TO_RIGHT || !mSpannedText) { return right; // leading margin has no impact, or no styles } return right - getParagraphLeadingMargin(line); } /** * Returns the effective leading margin (unsigned) for this line, * taking into account LeadingMarginSpan and LeadingMarginSpan2. * @param line the line index * @return the leading margin of this line */ private int getParagraphLeadingMargin(int line) { if (!mSpannedText) { return 0; } Spanned spanned = (Spanned) mText; int lineStart = getLineStart(line); int lineEnd = getLineEnd(line); int spanEnd = spanned.nextSpanTransition(lineStart, lineEnd, LeadingMarginSpan.class); LeadingMarginSpan[] spans = getParagraphSpans(spanned, lineStart, spanEnd, LeadingMarginSpan.class); if (spans.length == 0) { return 0; // no leading margin span; } int margin = 0; boolean useFirstLineMargin = lineStart == 0 || spanned.charAt(lineStart - 1) == '\n'; for (int i = 0; i < spans.length; i++) { if (spans[i] instanceof LeadingMarginSpan2) { int spStart = spanned.getSpanStart(spans[i]); int spanLine = getLineForOffset(spStart); int count = ((LeadingMarginSpan2) spans[i]).getLeadingMarginLineCount(); // if there is more than one LeadingMarginSpan2, use the count that is greatest useFirstLineMargin |= line < spanLine + count; } } for (int i = 0; i < spans.length; i++) { LeadingMarginSpan span = spans[i]; margin += span.getLeadingMargin(useFirstLineMargin); } return margin; } private static float measurePara(TextPaint paint, CharSequence text, int start, int end, TextDirectionHeuristic textDir) { MeasuredParagraph mt = null; TextLine tl = TextLine.obtain(); try { mt = MeasuredParagraph.buildForBidi(text, start, end, textDir, mt); final char[] chars = mt.getChars(); final int len = chars.length; final Directions directions = mt.getDirections(0, len); final int dir = mt.getParagraphDir(); boolean hasTabs = false; TabStops tabStops = null; // leading margins should be taken into account when measuring a paragraph int margin = 0; if (text instanceof Spanned) { Spanned spanned = (Spanned) text; LeadingMarginSpan[] spans = getParagraphSpans(spanned, start, end, LeadingMarginSpan.class); for (LeadingMarginSpan lms : spans) { margin += lms.getLeadingMargin(true); } } for (int i = 0; i < len; ++i) { if (chars[i] == '\t') { hasTabs = true; if (text instanceof Spanned) { Spanned spanned = (Spanned) text; int spanEnd = spanned.nextSpanTransition(start, end, TabStopSpan.class); TabStopSpan[] spans = getParagraphSpans(spanned, start, spanEnd, TabStopSpan.class); if (spans.length > 0) { tabStops = new TabStops(TAB_INCREMENT, spans); } } break; } } tl.set(paint, text, start, end, dir, directions, hasTabs, tabStops); return margin + Math.abs(tl.metrics(null)); } finally { TextLine.recycle(tl); if (mt != null) { mt.recycle(); } } } /** * @hide */ /* package */ static class TabStops { private int[] mStops; private int mNumStops; private int mIncrement; TabStops(int increment, Object[] spans) { reset(increment, spans); } void reset(int increment, Object[] spans) { this.mIncrement = increment; int ns = 0; if (spans != null) { int[] stops = this.mStops; for (Object o : spans) { if (o instanceof TabStopSpan) { if (stops == null) { stops = new int[10]; } else if (ns == stops.length) { int[] nstops = new int[ns * 2]; for (int i = 0; i < ns; ++i) { nstops[i] = stops[i]; } stops = nstops; } stops[ns++] = ((TabStopSpan) o).getTabStop(); } } if (ns > 1) { Arrays.sort(stops, 0, ns); } if (stops != this.mStops) { this.mStops = stops; } } this.mNumStops = ns; } float nextTab(float h) { int ns = this.mNumStops; if (ns > 0) { int[] stops = this.mStops; for (int i = 0; i < ns; ++i) { int stop = stops[i]; if (stop > h) { return stop; } } } return nextDefaultStop(h, mIncrement); } public static float nextDefaultStop(float h, int inc) { return ((int) ((h + inc) / inc)) * inc; } } /** * Returns the position of the next tab stop after h on the line. * * @param text the text * @param start start of the line * @param end limit of the line * @param h the current horizontal offset * @param tabs the tabs, can be null. If it is null, any tabs in effect * on the line will be used. If there are no tabs, a default offset * will be used to compute the tab stop. * @return the offset of the next tab stop. */ /* package */ static float nextTab(CharSequence text, int start, int end, float h, Object[] tabs) { float nh = Float.MAX_VALUE; boolean alltabs = false; if (text instanceof Spanned) { if (tabs == null) { tabs = getParagraphSpans((Spanned) text, start, end, TabStopSpan.class); alltabs = true; } for (int i = 0; i < tabs.length; i++) { if (!alltabs) { if (!(tabs[i] instanceof TabStopSpan)) continue; } int where = ((TabStopSpan) tabs[i]).getTabStop(); if (where < nh && where > h) nh = where; } if (nh != Float.MAX_VALUE) return nh; } return ((int) ((h + TAB_INCREMENT) / TAB_INCREMENT)) * TAB_INCREMENT; } protected final boolean isSpanned() { return mSpannedText; } /** * Returns the same as <code>text.getSpans()</code>, except where * <code>start</code> and <code>end</code> are the same and are not * at the very beginning of the text, in which case an empty array * is returned instead. * <p> * This is needed because of the special case that <code>getSpans()</code> * on an empty range returns the spans adjacent to that range, which is * primarily for the sake of <code>TextWatchers</code> so they will get * notifications when text goes from empty to non-empty. But it also * has the unfortunate side effect that if the text ends with an empty * paragraph, that paragraph accidentally picks up the styles of the * preceding paragraph (even though those styles will not be picked up * by new text that is inserted into the empty paragraph). * <p> * The reason it just checks whether <code>start</code> and <code>end</code> * is the same is that the only time a line can contain 0 characters * is if it is the final paragraph of the Layout; otherwise any line will * contain at least one printing or newline character. The reason for the * additional check if <code>start</code> is greater than 0 is that * if the empty paragraph is the entire content of the buffer, paragraph * styles that are already applied to the buffer will apply to text that * is inserted into it. */ /* package */static <T> T[] getParagraphSpans(Spanned text, int start, int end, Class<T> type) { if (start == end && start > 0) { return ArrayUtils.emptyArray(type); } if (text instanceof SpannableStringBuilder) { return ((SpannableStringBuilder) text).getSpans(start, end, type, false); } else { return text.getSpans(start, end, type); } } private void ellipsize(int start, int end, int line, char[] dest, int destoff, TextUtils.TruncateAt method) { final int ellipsisCount = getEllipsisCount(line); if (ellipsisCount == 0) { return; } final int ellipsisStart = getEllipsisStart(line); final int lineStart = getLineStart(line); final String ellipsisString = TextUtils.getEllipsisString(method); final int ellipsisStringLen = ellipsisString.length(); // Use the ellipsis string only if there are that at least as many characters to replace. final boolean useEllipsisString = ellipsisCount >= ellipsisStringLen; for (int i = 0; i < ellipsisCount; i++) { final char c; if (useEllipsisString && i < ellipsisStringLen) { c = ellipsisString.charAt(i); } else { c = TextUtils.ELLIPSIS_FILLER; } final int a = i + ellipsisStart + lineStart; if (start <= a && a < end) { dest[destoff + a - start] = c; } } } /** * Stores information about bidirectional (left-to-right or right-to-left) * text within the layout of a line. */ public static class Directions { /** * Directions represents directional runs within a line of text. Runs are pairs of ints * listed in visual order, starting from the leading margin. The first int of each pair is * the offset from the first character of the line to the start of the run. The second int * represents both the length and level of the run. The length is in the lower bits, * accessed by masking with RUN_LENGTH_MASK. The level is in the higher bits, accessed by * shifting by RUN_LEVEL_SHIFT and masking by RUN_LEVEL_MASK. To simply test for an RTL * direction, test the bit using RUN_RTL_FLAG, if set then the direction is rtl. * @hide */ @VisibleForTesting(visibility = VisibleForTesting.Visibility.PACKAGE) public int[] mDirections; /** * @hide */ @VisibleForTesting(visibility = VisibleForTesting.Visibility.PACKAGE) public Directions(int[] dirs) { mDirections = dirs; } } /** * Return the offset of the first character to be ellipsized away, * relative to the start of the line. (So 0 if the beginning of the * line is ellipsized, not getLineStart().) */ public abstract int getEllipsisStart(int line); /** * Returns the number of characters to be ellipsized away, or 0 if * no ellipsis is to take place. */ public abstract int getEllipsisCount(int line); /* package */ static class Ellipsizer implements CharSequence, GetChars { /* package */ CharSequence mText; /* package */ Layout mLayout; /* package */ int mWidth; /* package */ TextUtils.TruncateAt mMethod; public Ellipsizer(CharSequence s) { mText = s; } public char charAt(int off) { char[] buf = TextUtils.obtain(1); getChars(off, off + 1, buf, 0); char ret = buf[0]; TextUtils.recycle(buf); return ret; } public void getChars(int start, int end, char[] dest, int destoff) { int line1 = mLayout.getLineForOffset(start); int line2 = mLayout.getLineForOffset(end); TextUtils.getChars(mText, start, end, dest, destoff); for (int i = line1; i <= line2; i++) { mLayout.ellipsize(start, end, i, dest, destoff, mMethod); } } public int length() { return mText.length(); } public CharSequence subSequence(int start, int end) { char[] s = new char[end - start]; getChars(start, end, s, 0); return new String(s); } @Override public String toString() { char[] s = new char[length()]; getChars(0, length(), s, 0); return new String(s); } } /* package */ static class SpannedEllipsizer extends Ellipsizer implements Spanned { private Spanned mSpanned; public SpannedEllipsizer(CharSequence display) { super(display); mSpanned = (Spanned) display; } public <T> T[] getSpans(int start, int end, Class<T> type) { return mSpanned.getSpans(start, end, type); } public int getSpanStart(Object tag) { return mSpanned.getSpanStart(tag); } public int getSpanEnd(Object tag) { return mSpanned.getSpanEnd(tag); } public int getSpanFlags(Object tag) { return mSpanned.getSpanFlags(tag); } @SuppressWarnings("rawtypes") public int nextSpanTransition(int start, int limit, Class type) { return mSpanned.nextSpanTransition(start, limit, type); } @Override public CharSequence subSequence(int start, int end) { char[] s = new char[end - start]; getChars(start, end, s, 0); SpannableString ss = new SpannableString(new String(s)); TextUtils.copySpansFrom(mSpanned, start, end, Object.class, ss, 0); return ss; } } private CharSequence mText; @UnsupportedAppUsage private TextPaint mPaint; private TextPaint mWorkPaint = new TextPaint(); private int mWidth; private Alignment mAlignment = Alignment.ALIGN_NORMAL; private float mSpacingMult; private float mSpacingAdd; private static final Rect sTempRect = new Rect(); private boolean mSpannedText; private TextDirectionHeuristic mTextDir; private SpanSet<LineBackgroundSpan> mLineBackgroundSpans; private int mJustificationMode; /** @hide */ @IntDef(prefix = { "DIR_" }, value = { DIR_LEFT_TO_RIGHT, DIR_RIGHT_TO_LEFT }) @Retention(RetentionPolicy.SOURCE) public @interface Direction { } public static final int DIR_LEFT_TO_RIGHT = 1; public static final int DIR_RIGHT_TO_LEFT = -1; /* package */ static final int DIR_REQUEST_LTR = 1; /* package */ static final int DIR_REQUEST_RTL = -1; @UnsupportedAppUsage /* package */ static final int DIR_REQUEST_DEFAULT_LTR = 2; /* package */ static final int DIR_REQUEST_DEFAULT_RTL = -2; /* package */ static final int RUN_LENGTH_MASK = 0x03ffffff; /* package */ static final int RUN_LEVEL_SHIFT = 26; /* package */ static final int RUN_LEVEL_MASK = 0x3f; /* package */ static final int RUN_RTL_FLAG = 1 << RUN_LEVEL_SHIFT; public enum Alignment { ALIGN_NORMAL, ALIGN_OPPOSITE, ALIGN_CENTER, /** @hide */ @UnsupportedAppUsage ALIGN_LEFT, /** @hide */ @UnsupportedAppUsage ALIGN_RIGHT, } private static final int TAB_INCREMENT = 20; /** @hide */ @VisibleForTesting(visibility = VisibleForTesting.Visibility.PACKAGE) @UnsupportedAppUsage public static final Directions DIRS_ALL_LEFT_TO_RIGHT = new Directions(new int[] { 0, RUN_LENGTH_MASK }); /** @hide */ @VisibleForTesting(visibility = VisibleForTesting.Visibility.PACKAGE) @UnsupportedAppUsage public static final Directions DIRS_ALL_RIGHT_TO_LEFT = new Directions( new int[] { 0, RUN_LENGTH_MASK | RUN_RTL_FLAG }); /** @hide */ @Retention(RetentionPolicy.SOURCE) @IntDef(prefix = { "TEXT_SELECTION_LAYOUT_" }, value = { TEXT_SELECTION_LAYOUT_RIGHT_TO_LEFT, TEXT_SELECTION_LAYOUT_LEFT_TO_RIGHT }) public @interface TextSelectionLayout { } /** @hide */ public static final int TEXT_SELECTION_LAYOUT_RIGHT_TO_LEFT = 0; /** @hide */ public static final int TEXT_SELECTION_LAYOUT_LEFT_TO_RIGHT = 1; /** @hide */ @FunctionalInterface public interface SelectionRectangleConsumer { /** * Performs this operation on the given rectangle. * * @param left the left edge of the rectangle * @param top the top edge of the rectangle * @param right the right edge of the rectangle * @param bottom the bottom edge of the rectangle * @param textSelectionLayout the layout (RTL or LTR) of the text covered by this * selection rectangle */ void accept(float left, float top, float right, float bottom, @TextSelectionLayout int textSelectionLayout); } }