Android example source code file (Layout.java)
The Layout.java Android example source code/*
* 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.emoji.EmojiFactory;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Path;
import com.android.internal.util.ArrayUtils;
import junit.framework.Assert;
import android.text.style.*;
import android.text.method.TextKeyListener;
import android.view.KeyEvent;
/**
* 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 {
private static final boolean DEBUG = false;
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;
}
};
private RectF mEmojiRect;
/**
* 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;
TextPaint workPaint = new TextPaint();
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 = measureText(paint, workPaint,
source, i, next, null, true, null);
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) {
if (width < 0)
throw new IllegalArgumentException("Layout: " + width + " < 0");
mText = text;
mPaint = paint;
mWorkPaint = new TextPaint();
mWidth = width;
mAlignment = align;
mSpacingMult = spacingMult;
mSpacingAdd = spacingAdd;
mSpannedText = text instanceof Spanned;
}
/**
* 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 c 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 c, Path highlight, Paint highlightPaint,
int cursorOffsetVertical) {
int dtop, dbottom;
synchronized (sTempRect) {
if (!c.getClipBounds(sTempRect)) {
return;
}
dtop = sTempRect.top;
dbottom = sTempRect.bottom;
}
int top = 0;
int bottom = getLineTop(getLineCount());
if (dtop > top) {
top = dtop;
}
if (dbottom < bottom) {
bottom = dbottom;
}
int first = getLineForVertical(top);
int last = getLineForVertical(bottom);
int previousLineBottom = getLineTop(first);
int previousLineEnd = getLineStart(first);
TextPaint paint = mPaint;
CharSequence buf = mText;
int width = mWidth;
boolean spannedText = mSpannedText;
ParagraphStyle[] spans = NO_PARA_SPANS;
int spanend = 0;
int textLength = 0;
// First, draw LineBackgroundSpans.
// LineBackgroundSpans know nothing about the alignment or direction of
// the layout or line. XXX: Should they?
if (spannedText) {
textLength = buf.length();
for (int i = first; i <= last; 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) {
Spanned sp = (Spanned) buf;
spanend = sp.nextSpanTransition(start, textLength,
LineBackgroundSpan.class);
spans = sp.getSpans(start, spanend,
LineBackgroundSpan.class);
}
for (int n = 0; n < spans.length; n++) {
LineBackgroundSpan back = (LineBackgroundSpan) spans[n];
back.drawBackground(c, paint, 0, width,
ltop, lbaseline, lbottom,
buf, start, end,
i);
}
}
// reset to their original values
spanend = 0;
previousLineBottom = getLineTop(first);
previousLineEnd = getLineStart(first);
spans = NO_PARA_SPANS;
}
// 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) {
c.translate(0, cursorOffsetVertical);
}
c.drawPath(highlight, highlightPaint);
if (cursorOffsetVertical != 0) {
c.translate(0, -cursorOffsetVertical);
}
}
Alignment align = mAlignment;
// Next draw the lines, one at a time.
// the baseline is the top of the following line minus the current
// line's descent.
for (int i = first; i <= last; i++) {
int start = previousLineEnd;
previousLineEnd = getLineStart(i+1);
int end = getLineVisibleEnd(i, start, previousLineEnd);
int ltop = previousLineBottom;
int lbottom = getLineTop(i+1);
previousLineBottom = lbottom;
int lbaseline = lbottom - getLineDescent(i);
boolean isFirstParaLine = false;
if (spannedText) {
if (start == 0 || buf.charAt(start - 1) == '\n') {
isFirstParaLine = true;
}
// New batch of paragraph styles, compute the alignment.
// Last alignment style wins.
if (start >= spanend) {
Spanned sp = (Spanned) buf;
spanend = sp.nextSpanTransition(start, textLength,
ParagraphStyle.class);
spans = sp.getSpans(start, spanend, ParagraphStyle.class);
align = mAlignment;
for (int n = spans.length-1; n >= 0; n--) {
if (spans[n] instanceof AlignmentSpan) {
align = ((AlignmentSpan) spans[n]).getAlignment();
break;
}
}
}
}
int dir = getParagraphDirection(i);
int left = 0;
int right = mWidth;
// Draw all leading margin spans. Adjust left or right according
// to the paragraph direction of the line.
if (spannedText) {
final int length = spans.length;
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(c, paint, right, dir, ltop,
lbaseline, lbottom, buf,
start, end, isFirstParaLine, this);
right -= margin.getLeadingMargin(isFirstParaLine);
} else {
margin.drawLeadingMargin(c, paint, left, dir, ltop,
lbaseline, lbottom, buf,
start, end, isFirstParaLine, this);
boolean useMargin = isFirstParaLine;
if (margin instanceof LeadingMarginSpan.LeadingMarginSpan2) {
int count = ((LeadingMarginSpan.LeadingMarginSpan2)margin).getLeadingMarginLineCount();
useMargin = count > i;
}
left += margin.getLeadingMargin(useMargin);
}
}
}
}
// Adjust the point at which to start rendering depending on the
// alignment of the paragraph.
int x;
if (align == Alignment.ALIGN_NORMAL) {
if (dir == DIR_LEFT_TO_RIGHT) {
x = left;
} else {
x = right;
}
} else {
int max = (int)getLineMax(i, spans, false);
if (align == Alignment.ALIGN_OPPOSITE) {
if (dir == DIR_RIGHT_TO_LEFT) {
x = left + max;
} else {
x = right - max;
}
} else {
// Alignment.ALIGN_CENTER
max = max & ~1;
int half = (right - left - max) >> 1;
if (dir == DIR_RIGHT_TO_LEFT) {
x = right - half;
} else {
x = left + half;
}
}
}
Directions directions = getLineDirections(i);
boolean hasTab = getLineContainsTab(i);
if (directions == DIRS_ALL_LEFT_TO_RIGHT &&
!spannedText && !hasTab) {
if (DEBUG) {
Assert.assertTrue(dir == DIR_LEFT_TO_RIGHT);
Assert.assertNotNull(c);
}
// XXX: assumes there's nothing additional to be done
c.drawText(buf, start, end, x, lbaseline, paint);
} else {
drawText(c, buf, start, end, dir, directions,
x, ltop, lbaseline, lbottom, paint, mWorkPaint,
hasTab, spans);
}
}
}
/**
* 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 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 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
* 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();
/**
* 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 getHorizontal(offset, false, true);
}
/**
* 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 getHorizontal(offset, true, true);
}
private float getHorizontal(int offset, boolean trailing, boolean alt) {
int line = getLineForOffset(offset);
return getHorizontal(offset, trailing, alt, line);
}
private float getHorizontal(int offset, boolean trailing, boolean alt,
int line) {
int start = getLineStart(line);
int end = getLineVisibleEnd(line);
int dir = getParagraphDirection(line);
boolean tab = getLineContainsTab(line);
Directions directions = getLineDirections(line);
TabStopSpan[] tabs = null;
if (tab && mText instanceof Spanned) {
tabs = ((Spanned) mText).getSpans(start, end, TabStopSpan.class);
}
float wid = measureText(mPaint, mWorkPaint, mText, start, offset, end,
dir, directions, trailing, alt, tab, tabs);
if (offset > end) {
if (dir == DIR_RIGHT_TO_LEFT)
wid -= measureText(mPaint, mWorkPaint,
mText, end, offset, null, tab, tabs);
else
wid += measureText(mPaint, mWorkPaint,
mText, end, offset, null, tab, tabs);
}
Alignment align = getParagraphAlignment(line);
int left = getParagraphLeft(line);
int right = getParagraphRight(line);
if (align == Alignment.ALIGN_NORMAL) {
if (dir == DIR_RIGHT_TO_LEFT)
return right + wid;
else
return left + wid;
}
float max = getLineMax(line);
if (align == Alignment.ALIGN_OPPOSITE) {
if (dir == DIR_RIGHT_TO_LEFT)
return left + max + wid;
else
return right - max + wid;
} else { /* align == Alignment.ALIGN_CENTER */
int imax = ((int) max) & ~1;
if (dir == DIR_RIGHT_TO_LEFT)
return right - (((right - left) - imax) / 2) + wid;
else
return left + ((right - left) - imax) / 2 + 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_NORMAL) {
if (dir == DIR_RIGHT_TO_LEFT)
return getParagraphRight(line) - getLineMax(line);
else
return 0;
} 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_NORMAL) {
if (dir == DIR_RIGHT_TO_LEFT)
return mWidth;
else
return getParagraphLeft(line) + getLineMax(line);
} 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 horizontal extent of the specified line, excluding
* trailing whitespace.
*/
public float getLineMax(int line) {
return getLineMax(line, null, false);
}
/**
* Gets the horizontal extent of the specified line, including
* trailing whitespace.
*/
public float getLineWidth(int line) {
return getLineMax(line, null, true);
}
private float getLineMax(int line, Object[] tabs, boolean full) {
int start = getLineStart(line);
int end;
if (full) {
end = getLineEnd(line);
} else {
end = getLineVisibleEnd(line);
}
boolean tab = getLineContainsTab(line);
if (tabs == null && tab && mText instanceof Spanned) {
tabs = ((Spanned) mText).getSpans(start, end, TabStopSpan.class);
}
return measureText(mPaint, mWorkPaint,
mText, start, end, null, tab, tabs);
}
/**
* 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 specfied line whose position is
* closest to the specified horizontal position.
*/
public int getOffsetForHorizontal(int line, float horiz) {
int max = getLineEnd(line) - 1;
int min = getLineStart(line);
Directions dirs = getLineDirections(line);
if (line == getLineCount() - 1)
max++;
if (line != getLineCount() - 1)
max = TextUtils.getOffsetBefore(mText, getLineEnd(line));
int best = min;
float bestdist = Math.abs(getPrimaryHorizontal(best) - horiz);
int here = min;
for (int i = 0; i < dirs.mDirections.length; i++) {
int there = here + dirs.mDirections[i];
int swap = ((i & 1) == 0) ? 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 (getPrimaryHorizontal(adguess) * swap >= horiz * swap)
high = guess;
else
low = guess;
}
if (low < here + 1)
low = here + 1;
if (low < there) {
low = getOffsetAtStartOf(low);
float dist = Math.abs(getPrimaryHorizontal(low) - horiz);
int aft = TextUtils.getOffsetAfter(mText, low);
if (aft < there) {
float other = Math.abs(getPrimaryHorizontal(aft) - horiz);
if (other < dist) {
dist = other;
low = aft;
}
}
if (dist < bestdist) {
bestdist = dist;
best = low;
}
}
float dist = Math.abs(getPrimaryHorizontal(here) - horiz);
if (dist < bestdist) {
bestdist = dist;
best = here;
}
here = there;
}
float dist = Math.abs(getPrimaryHorizontal(max) - horiz);
if (dist < bestdist) {
bestdist = dist;
best = max;
}
return best;
}
/**
* 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) {
if (DEBUG) {
Assert.assertTrue(getLineStart(line) == start && getLineStart(line+1) == 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 (ch != ' ' && ch != '\t') {
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 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 text offset that would be reached by moving left
* (possibly onto another line) from the specified offset.
*/
public int getOffsetToLeftOf(int offset) {
int line = getLineForOffset(offset);
int start = getLineStart(line);
int end = getLineEnd(line);
Directions dirs = getLineDirections(line);
if (line != getLineCount() - 1)
end = TextUtils.getOffsetBefore(mText, end);
float horiz = getPrimaryHorizontal(offset);
int best = offset;
float besth = Integer.MIN_VALUE;
int candidate;
candidate = TextUtils.getOffsetBefore(mText, offset);
if (candidate >= start && candidate <= end) {
float h = getPrimaryHorizontal(candidate);
if (h < horiz && h > besth) {
best = candidate;
besth = h;
}
}
candidate = TextUtils.getOffsetAfter(mText, offset);
if (candidate >= start && candidate <= end) {
float h = getPrimaryHorizontal(candidate);
if (h < horiz && h > besth) {
best = candidate;
besth = h;
}
}
int here = start;
for (int i = 0; i < dirs.mDirections.length; i++) {
int there = here + dirs.mDirections[i];
if (there > end)
there = end;
float h = getPrimaryHorizontal(here);
if (h < horiz && h > besth) {
best = here;
besth = h;
}
candidate = TextUtils.getOffsetAfter(mText, here);
if (candidate >= start && candidate <= end) {
h = getPrimaryHorizontal(candidate);
if (h < horiz && h > besth) {
best = candidate;
besth = h;
}
}
candidate = TextUtils.getOffsetBefore(mText, there);
if (candidate >= start && candidate <= end) {
h = getPrimaryHorizontal(candidate);
if (h < horiz && h > besth) {
best = candidate;
besth = h;
}
}
here = there;
}
float h = getPrimaryHorizontal(end);
if (h < horiz && h > besth) {
best = end;
besth = h;
}
if (best != offset)
return best;
int dir = getParagraphDirection(line);
if (dir > 0) {
if (line == 0)
return best;
else
return getOffsetForHorizontal(line - 1, 10000);
} else {
if (line == getLineCount() - 1)
return best;
else
return getOffsetForHorizontal(line + 1, 10000);
}
}
/**
* Return the text offset that would be reached by moving right
* (possibly onto another line) from the specified offset.
*/
public int getOffsetToRightOf(int offset) {
int line = getLineForOffset(offset);
int start = getLineStart(line);
int end = getLineEnd(line);
Directions dirs = getLineDirections(line);
if (line != getLineCount() - 1)
end = TextUtils.getOffsetBefore(mText, end);
float horiz = getPrimaryHorizontal(offset);
int best = offset;
float besth = Integer.MAX_VALUE;
int candidate;
candidate = TextUtils.getOffsetBefore(mText, offset);
if (candidate >= start && candidate <= end) {
float h = getPrimaryHorizontal(candidate);
if (h > horiz && h < besth) {
best = candidate;
besth = h;
}
}
candidate = TextUtils.getOffsetAfter(mText, offset);
if (candidate >= start && candidate <= end) {
float h = getPrimaryHorizontal(candidate);
if (h > horiz && h < besth) {
best = candidate;
besth = h;
}
}
int here = start;
for (int i = 0; i < dirs.mDirections.length; i++) {
int there = here + dirs.mDirections[i];
if (there > end)
there = end;
float h = getPrimaryHorizontal(here);
if (h > horiz && h < besth) {
best = here;
besth = h;
}
candidate = TextUtils.getOffsetAfter(mText, here);
if (candidate >= start && candidate <= end) {
h = getPrimaryHorizontal(candidate);
if (h > horiz && h < besth) {
best = candidate;
besth = h;
}
}
candidate = TextUtils.getOffsetBefore(mText, there);
if (candidate >= start && candidate <= end) {
h = getPrimaryHorizontal(candidate);
if (h > horiz && h < besth) {
best = candidate;
besth = h;
}
}
here = there;
}
float h = getPrimaryHorizontal(end);
if (h > horiz && h < besth) {
best = end;
besth = h;
}
if (best != offset)
return best;
int dir = getParagraphDirection(line);
if (dir > 0) {
if (line == getLineCount() - 1)
return best;
else
return getOffsetForHorizontal(line + 1, -10000);
} else {
if (line == 0)
return best;
else
return getOffsetForHorizontal(line - 1, -10000);
}
}
private int getOffsetAtStartOf(int offset) {
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;
}
/**
* 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 discontinous lines in text with multiple
* directionalities.
*/
public void getCursorPath(int point, Path dest,
CharSequence editingBuffer) {
dest.reset();
int line = getLineForOffset(point);
int top = getLineTop(line);
int bottom = getLineTop(line+1);
float h1 = getPrimaryHorizontal(point) - 0.5f;
float h2 = getSecondaryHorizontal(point) - 0.5f;
int caps = TextKeyListener.getMetaState(editingBuffer,
KeyEvent.META_SHIFT_ON) |
TextKeyListener.getMetaState(editingBuffer,
TextKeyListener.META_SELECTING);
int fn = TextKeyListener.getMetaState(editingBuffer,
KeyEvent.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 (h1 == h2) {
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, Path dest) {
int linestart = getLineStart(line);
int lineend = getLineEnd(line);
Directions dirs = getLineDirections(line);
if (lineend > linestart && mText.charAt(lineend - 1) == '\n')
lineend--;
int here = linestart;
for (int i = 0; i < dirs.mDirections.length; i++) {
int there = here + dirs.mDirections[i];
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, false, line);
float h2 = getHorizontal(en, true, false, line);
dest.addRect(h1, top, h2, bottom, Path.Direction.CW);
}
}
here = there;
}
}
/**
* 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();
if (start == end)
return;
if (end < start) {
int temp = end;
end = start;
start = temp;
}
int startline = getLineForOffset(start);
int endline = getLineForOffset(end);
int top = getLineTop(startline);
int bottom = getLineBottom(endline);
if (startline == endline) {
addSelection(startline, start, end, top, bottom, dest);
} else {
final float width = mWidth;
addSelection(startline, start, getLineEnd(startline),
top, getLineBottom(startline), dest);
if (getParagraphDirection(startline) == DIR_RIGHT_TO_LEFT)
dest.addRect(getLineLeft(startline), top,
0, getLineBottom(startline), Path.Direction.CW);
else
dest.addRect(getLineRight(startline), top,
width, getLineBottom(startline), Path.Direction.CW);
for (int i = startline + 1; i < endline; i++) {
top = getLineTop(i);
bottom = getLineBottom(i);
dest.addRect(0, top, width, bottom, Path.Direction.CW);
}
top = getLineTop(endline);
bottom = getLineBottom(endline);
addSelection(endline, getLineStart(endline), end,
top, bottom, dest);
if (getParagraphDirection(endline) == DIR_RIGHT_TO_LEFT)
dest.addRect(width, top, getLineRight(endline), bottom, Path.Direction.CW);
else
dest.addRect(0, top, getLineLeft(endline), bottom, Path.Direction.CW);
}
}
/**
* 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 = sp.getSpans(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 dir = getParagraphDirection(line);
int left = 0;
boolean par = false;
int off = getLineStart(line);
if (off == 0 || mText.charAt(off - 1) == '\n')
par = true;
if (dir == DIR_LEFT_TO_RIGHT) {
if (mSpannedText) {
Spanned sp = (Spanned) mText;
LeadingMarginSpan[] spans = sp.getSpans(getLineStart(line),
getLineEnd(line),
LeadingMarginSpan.class);
for (int i = 0; i < spans.length; i++) {
boolean margin = par;
LeadingMarginSpan span = spans[i];
if (span instanceof LeadingMarginSpan.LeadingMarginSpan2) {
int count = ((LeadingMarginSpan.LeadingMarginSpan2)span).getLeadingMarginLineCount();
margin = count >= line;
}
left += span.getLeadingMargin(margin);
}
}
}
return left;
}
/**
* Get the right edge of the specified paragraph, inset by right margins.
*/
public final int getParagraphRight(int line) {
int dir = getParagraphDirection(line);
int right = mWidth;
boolean par = false;
int off = getLineStart(line);
if (off == 0 || mText.charAt(off - 1) == '\n')
par = true;
if (dir == DIR_RIGHT_TO_LEFT) {
if (mSpannedText) {
Spanned sp = (Spanned) mText;
LeadingMarginSpan[] spans = sp.getSpans(getLineStart(line),
getLineEnd(line),
LeadingMarginSpan.class);
for (int i = 0; i < spans.length; i++) {
right -= spans[i].getLeadingMargin(par);
}
}
}
return right;
}
private void drawText(Canvas canvas,
CharSequence text, int start, int end,
int dir, Directions directions,
float x, int top, int y, int bottom,
TextPaint paint,
TextPaint workPaint,
boolean hasTabs, Object[] parspans) {
char[] buf;
if (!hasTabs) {
if (directions == DIRS_ALL_LEFT_TO_RIGHT) {
if (DEBUG) {
Assert.assertTrue(DIR_LEFT_TO_RIGHT == dir);
}
Styled.drawText(canvas, text, start, end, dir, false, x, top, y, bottom, paint, workPaint, false);
return;
}
buf = null;
} else {
buf = TextUtils.obtain(end - start);
TextUtils.getChars(text, start, end, buf, 0);
}
float h = 0;
int here = 0;
for (int i = 0; i < directions.mDirections.length; i++) {
int there = here + directions.mDirections[i];
if (there > end - start)
there = end - start;
int segstart = here;
for (int j = hasTabs ? here : there; j <= there; j++) {
if (j == there || buf[j] == '\t') {
h += Styled.drawText(canvas, text,
start + segstart, start + j,
dir, (i & 1) != 0, x + h,
top, y, bottom, paint, workPaint,
start + j != end);
if (j != there && buf[j] == '\t')
h = dir * nextTab(text, start, end, h * dir, parspans);
segstart = j + 1;
} else if (hasTabs && buf[j] >= 0xD800 && buf[j] <= 0xDFFF && j + 1 < there) {
int emoji = Character.codePointAt(buf, j);
if (emoji >= MIN_EMOJI && emoji <= MAX_EMOJI) {
Bitmap bm = EMOJI_FACTORY.
getBitmapFromAndroidPua(emoji);
if (bm != null) {
h += Styled.drawText(canvas, text,
start + segstart, start + j,
dir, (i & 1) != 0, x + h,
top, y, bottom, paint, workPaint,
start + j != end);
if (mEmojiRect == null) {
mEmojiRect = new RectF();
}
workPaint.set(paint);
Styled.measureText(paint, workPaint, text,
start + j, start + j + 1,
null);
float bitmapHeight = bm.getHeight();
float textHeight = -workPaint.ascent();
float scale = textHeight / bitmapHeight;
float width = bm.getWidth() * scale;
mEmojiRect.set(x + h, y - textHeight,
x + h + width, y);
canvas.drawBitmap(bm, null, mEmojiRect, paint);
h += width;
j++;
segstart = j + 1;
}
}
}
}
here = there;
}
if (hasTabs)
TextUtils.recycle(buf);
}
private static float measureText(TextPaint paint,
TextPaint workPaint,
CharSequence text,
int start, int offset, int end,
int dir, Directions directions,
boolean trailing, boolean alt,
boolean hasTabs, Object[] tabs) {
char[] buf = null;
if (hasTabs) {
buf = TextUtils.obtain(end - start);
TextUtils.getChars(text, start, end, buf, 0);
}
float h = 0;
if (alt) {
if (dir == DIR_RIGHT_TO_LEFT)
trailing = !trailing;
}
int here = 0;
for (int i = 0; i < directions.mDirections.length; i++) {
if (alt)
trailing = !trailing;
int there = here + directions.mDirections[i];
if (there > end - start)
there = end - start;
int segstart = here;
for (int j = hasTabs ? here : there; j <= there; j++) {
int codept = 0;
Bitmap bm = null;
if (hasTabs && j < there) {
codept = buf[j];
}
if (codept >= 0xD800 && codept <= 0xDFFF && j + 1 < there) {
codept = Character.codePointAt(buf, j);
if (codept >= MIN_EMOJI && codept <= MAX_EMOJI) {
bm = EMOJI_FACTORY.getBitmapFromAndroidPua(codept);
}
}
if (j == there || codept == '\t' || bm != null) {
float segw;
if (offset < start + j ||
(trailing && offset <= start + j)) {
if (dir == DIR_LEFT_TO_RIGHT && (i & 1) == 0) {
h += Styled.measureText(paint, workPaint, text,
start + segstart, offset,
null);
return h;
}
if (dir == DIR_RIGHT_TO_LEFT && (i & 1) != 0) {
h -= Styled.measureText(paint, workPaint, text,
start + segstart, offset,
null);
return h;
}
}
segw = Styled.measureText(paint, workPaint, text,
start + segstart, start + j,
null);
if (offset < start + j ||
(trailing && offset <= start + j)) {
if (dir == DIR_LEFT_TO_RIGHT) {
h += segw - Styled.measureText(paint, workPaint,
text,
start + segstart,
offset, null);
return h;
}
if (dir == DIR_RIGHT_TO_LEFT) {
h -= segw - Styled.measureText(paint, workPaint,
text,
start + segstart,
offset, null);
return h;
}
}
if (dir == DIR_RIGHT_TO_LEFT)
h -= segw;
else
h += segw;
if (j != there && buf[j] == '\t') {
if (offset == start + j)
return h;
h = dir * nextTab(text, start, end, h * dir, tabs);
}
if (j != there && bm != null) {
if (offset == start + j) return h;
workPaint.set(paint);
Styled.measureText(paint, workPaint, text,
j, j + 2, null);
float wid = (float) bm.getWidth() *
-workPaint.ascent() / bm.getHeight();
if (dir == DIR_RIGHT_TO_LEFT) {
h -= wid;
} else {
h += wid;
}
j++;
}
segstart = j + 1;
}
}
here = there;
}
if (hasTabs)
TextUtils.recycle(buf);
return h;
}
/**
* Measure width of a run of text on a single line that is known to all be
* in the same direction as the paragraph base direction. Returns the width,
* and the line metrics in fm if fm is not null.
*
* @param paint the paint for the text; will not be modified
* @param workPaint paint available for modification
* @param text text
* @param start start of the line
* @param end limit of the line
* @param fm object to return integer metrics in, can be null
* @param hasTabs true if it is known that the line has tabs
* @param tabs tab position information
* @return the width of the text from start to end
*/
/* package */ static float measureText(TextPaint paint,
TextPaint workPaint,
CharSequence text,
int start, int end,
Paint.FontMetricsInt fm,
boolean hasTabs, Object[] tabs) {
char[] buf = null;
if (hasTabs) {
buf = TextUtils.obtain(end - start);
TextUtils.getChars(text, start, end, buf, 0);
}
int len = end - start;
int lastPos = 0;
float width = 0;
int ascent = 0, descent = 0, top = 0, bottom = 0;
if (fm != null) {
fm.ascent = 0;
fm.descent = 0;
}
for (int pos = hasTabs ? 0 : len; pos <= len; pos++) {
int codept = 0;
Bitmap bm = null;
if (hasTabs && pos < len) {
codept = buf[pos];
}
if (codept >= 0xD800 && codept <= 0xDFFF && pos < len) {
codept = Character.codePointAt(buf, pos);
if (codept >= MIN_EMOJI && codept <= MAX_EMOJI) {
bm = EMOJI_FACTORY.getBitmapFromAndroidPua(codept);
}
}
if (pos == len || codept == '\t' || bm != null) {
workPaint.baselineShift = 0;
width += Styled.measureText(paint, workPaint, text,
start + lastPos, start + pos,
fm);
if (fm != null) {
if (workPaint.baselineShift < 0) {
fm.ascent += workPaint.baselineShift;
fm.top += workPaint.baselineShift;
} else {
fm.descent += workPaint.baselineShift;
fm.bottom += workPaint.baselineShift;
}
}
if (pos != len) {
if (bm == null) {
// no emoji, must have hit a tab
width = nextTab(text, start, end, width, tabs);
} else {
// This sets up workPaint with the font on the emoji
// text, so that we can extract the ascent and scale.
// We can't use the result of the previous call to
// measureText because the emoji might have its own style.
// We have to initialize workPaint here because if the
// text is unstyled measureText might not use workPaint
// at all.
workPaint.set(paint);
Styled.measureText(paint, workPaint, text,
start + pos, start + pos + 1, null);
width += (float) bm.getWidth() *
-workPaint.ascent() / bm.getHeight();
// Since we had an emoji, we bump past the second half
// of the surrogate pair.
pos++;
}
}
if (fm != null) {
if (fm.ascent < ascent) {
ascent = fm.ascent;
}
if (fm.descent > descent) {
descent = fm.descent;
}
if (fm.top < top) {
top = fm.top;
}
if (fm.bottom > bottom) {
bottom = fm.bottom;
}
// No need to take bitmap height into account here,
// since it is scaled to match the text height.
}
lastPos = pos + 1;
}
}
if (fm != null) {
fm.ascent = ascent;
fm.descent = descent;
fm.top = top;
fm.bottom = bottom;
}
if (hasTabs)
TextUtils.recycle(buf);
return width;
}
/**
* 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 = ((Spanned) text).getSpans(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;
}
private void ellipsize(int start, int end, int line,
char[] dest, int destoff) {
int ellipsisCount = getEllipsisCount(line);
if (ellipsisCount == 0) {
return;
}
int ellipsisStart = getEllipsisStart(line);
int linestart = getLineStart(line);
for (int i = ellipsisStart; i < ellipsisStart + ellipsisCount; i++) {
char c;
if (i == ellipsisStart) {
c = '\u2026'; // ellipsis
} else {
c = '\uFEFF'; // 0-width space
}
int a = i + linestart;
if (a >= start && 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. TODO: This work is not complete
* or correct and will be fleshed out in a later revision.
*/
public static class Directions {
private short[] mDirections;
// The values in mDirections are the offsets from the first character
// in the line to the next flip in direction. Runs at even indices
// are left-to-right, the others are right-to-left. So, for example,
// a line that starts with a right-to-left run has 0 at mDirections[0],
// since the 'first' (ltr) run is zero length.
//
// The code currently assumes that each run is adjacent to the previous
// one, progressing in the base line direction. This isn't sufficient
// to handle nested runs, for example numeric text in an rtl context
// in an ltr paragraph.
/* package */ Directions(short[] 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);
}
}
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);
}
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
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