/*

* 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.emoji.EmojiFactory;

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.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({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({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);

/* package */ static final EmojiFactory EMOJI_FACTORY = EmojiFactory.newAvailableInstance();

/* package */ static final int MIN_EMOJI, MAX_EMOJI;

static {

if (EMOJI_FACTORY != null) {

MIN_EMOJI = EMOJI_FACTORY.getMinimumAndroidPua();

MAX_EMOJI = EMOJI_FACTORY.getMaximumAndroidPua();

} else {

MIN_EMOJI = -1;

MAX_EMOJI = -1;

}

}

/**

* Return how wide a layout must be in order to display the

* specified text with one line per paragraph.

*/

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.

*/

public static float getDesiredWidth(CharSequence source,

int start, int end,

TextPaint paint) {

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);

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;

}

/**

* 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);

}

/**

* @hide

*/

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;

TextPaint paint = 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);

int end = getLineVisibleEnd(lineNum, start, previousLineEnd);

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 hasTabOrEmoji = getLineContainsTab(lineNum);

// Can't tell if we have tabs for sure, currently

if (hasTabOrEmoji && !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;

if (align == Alignment.ALIGN_NORMAL) {

if (dir == DIR_LEFT_TO_RIGHT) {

x = left + getIndentAdjust(lineNum, Alignment.ALIGN_LEFT);

} else {

x = right + getIndentAdjust(lineNum, Alignment.ALIGN_RIGHT);

}

} else {

int max = (int)getLineExtent(lineNum, tabStops, false);

if (align == Alignment.ALIGN_OPPOSITE) {

if (dir == DIR_LEFT_TO_RIGHT) {

x = right - max + getIndentAdjust(lineNum, Alignment.ALIGN_RIGHT);

} else {

x = left - max + getIndentAdjust(lineNum, Alignment.ALIGN_LEFT);

}

} else { // Alignment.ALIGN_CENTER

max = max & ~1;

x = ((right + left - max) >> 1) +

getIndentAdjust(lineNum, Alignment.ALIGN_CENTER);

}

}

paint.setHyphenEdit(getHyphen(lineNum));

Directions directions = getLineDirections(lineNum);

if (directions == DIRS_ALL_LEFT_TO_RIGHT && !mSpannedText && !hasTabOrEmoji) {

// 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, hasTabOrEmoji, tabStops);

tl.draw(canvas, x, ltop, lbaseline, lbottom);

}

paint.setHyphenEdit(0);

}

TextLine.recycle(tl);

}

/**

* @hide

*/

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

*/

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&mdash;

* 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 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&hellip;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&hellip;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&hellip;getLineCount() - 1).

*/

public abstract int getLineDescent(int line);

/**

* Return the text offset of the beginning of the specified line (

* 0&hellip;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

* or emoji.

*/

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

*/

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;

}

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;

}

/**

* 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

*/

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

*/

public float getSecondaryHorizontal(int offset, boolean clamped) {

boolean trailing = primaryIsTrailingPrevious(offset);

return getHorizontal(offset, !trailing, clamped);

}

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 hasTabOrEmoji = getLineContainsTab(line);

Directions directions = getLineDirections(line);

TabStops tabStops = null;

if (hasTabOrEmoji && 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, hasTabOrEmoji, 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;

}

/**

* 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;

}