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/*
* Copyright (C) 2010 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.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Paint.FontMetricsInt;
import android.graphics.RectF;
import android.text.Layout.Directions;
import android.text.Layout.TabStops;
import android.text.style.CharacterStyle;
import android.text.style.MetricAffectingSpan;
import android.text.style.ReplacementSpan;
import android.util.Log;
import com.android.internal.util.ArrayUtils;
/**
* Represents a line of styled text, for measuring in visual order and
* for rendering.
*
* Get a new instance using obtain(), and when finished with it, return it
* to the pool using recycle().
*
*
Call set to prepare the instance for use, then either draw, measure,
* metrics, or caretToLeftRightOf.
*
* @hide
*/
class TextLine {
private static final boolean DEBUG = false;
private TextPaint mPaint;
private CharSequence mText;
private int mStart;
private int mLen;
private int mDir;
private Directions mDirections;
private boolean mHasTabs;
private TabStops mTabs;
private char[] mChars;
private boolean mCharsValid;
private Spanned mSpanned;
private final TextPaint mWorkPaint = new TextPaint();
private final SpanSet mMetricAffectingSpanSpanSet =
new SpanSet(MetricAffectingSpan.class);
private final SpanSet mCharacterStyleSpanSet =
new SpanSet(CharacterStyle.class);
private final SpanSet mReplacementSpanSpanSet =
new SpanSet(ReplacementSpan.class);
private static final TextLine[] sCached = new TextLine[3];
/**
* Returns a new TextLine from the shared pool.
*
* @return an uninitialized TextLine
*/
static TextLine obtain() {
TextLine tl;
synchronized (sCached) {
for (int i = sCached.length; --i >= 0;) {
if (sCached[i] != null) {
tl = sCached[i];
sCached[i] = null;
return tl;
}
}
}
tl = new TextLine();
if (DEBUG) {
Log.v("TLINE", "new: " + tl);
}
return tl;
}
/**
* Puts a TextLine back into the shared pool. Do not use this TextLine once
* it has been returned.
* @param tl the textLine
* @return null, as a convenience from clearing references to the provided
* TextLine
*/
static TextLine recycle(TextLine tl) {
tl.mText = null;
tl.mPaint = null;
tl.mDirections = null;
tl.mMetricAffectingSpanSpanSet.recycle();
tl.mCharacterStyleSpanSet.recycle();
tl.mReplacementSpanSpanSet.recycle();
synchronized(sCached) {
for (int i = 0; i < sCached.length; ++i) {
if (sCached[i] == null) {
sCached[i] = tl;
break;
}
}
}
return null;
}
/**
* Initializes a TextLine and prepares it for use.
*
* @param paint the base paint for the line
* @param text the text, can be Styled
* @param start the start of the line relative to the text
* @param limit the limit of the line relative to the text
* @param dir the paragraph direction of this line
* @param directions the directions information of this line
* @param hasTabs true if the line might contain tabs or emoji
* @param tabStops the tabStops. Can be null.
*/
void set(TextPaint paint, CharSequence text, int start, int limit, int dir,
Directions directions, boolean hasTabs, TabStops tabStops) {
mPaint = paint;
mText = text;
mStart = start;
mLen = limit - start;
mDir = dir;
mDirections = directions;
if (mDirections == null) {
throw new IllegalArgumentException("Directions cannot be null");
}
mHasTabs = hasTabs;
mSpanned = null;
boolean hasReplacement = false;
if (text instanceof Spanned) {
mSpanned = (Spanned) text;
mReplacementSpanSpanSet.init(mSpanned, start, limit);
hasReplacement = mReplacementSpanSpanSet.numberOfSpans > 0;
}
mCharsValid = hasReplacement || hasTabs || directions != Layout.DIRS_ALL_LEFT_TO_RIGHT;
if (mCharsValid) {
if (mChars == null || mChars.length < mLen) {
mChars = new char[ArrayUtils.idealCharArraySize(mLen)];
}
TextUtils.getChars(text, start, limit, mChars, 0);
if (hasReplacement) {
// Handle these all at once so we don't have to do it as we go.
// Replace the first character of each replacement run with the
// object-replacement character and the remainder with zero width
// non-break space aka BOM. Cursor movement code skips these
// zero-width characters.
char[] chars = mChars;
for (int i = start, inext; i < limit; i = inext) {
inext = mReplacementSpanSpanSet.getNextTransition(i, limit);
if (mReplacementSpanSpanSet.hasSpansIntersecting(i, inext)) {
// transition into a span
chars[i - start] = '\ufffc';
for (int j = i - start + 1, e = inext - start; j < e; ++j) {
chars[j] = '\ufeff'; // used as ZWNBS, marks positions to skip
}
}
}
}
}
mTabs = tabStops;
}
/**
* Renders the TextLine.
*
* @param c the canvas to render on
* @param x the leading margin position
* @param top the top of the line
* @param y the baseline
* @param bottom the bottom of the line
*/
void draw(Canvas c, float x, int top, int y, int bottom) {
if (!mHasTabs) {
if (mDirections == Layout.DIRS_ALL_LEFT_TO_RIGHT) {
drawRun(c, 0, mLen, false, x, top, y, bottom, false);
return;
}
if (mDirections == Layout.DIRS_ALL_RIGHT_TO_LEFT) {
drawRun(c, 0, mLen, true, x, top, y, bottom, false);
return;
}
}
float h = 0;
int[] runs = mDirections.mDirections;
RectF emojiRect = null;
int lastRunIndex = runs.length - 2;
for (int i = 0; i < runs.length; i += 2) {
int runStart = runs[i];
int runLimit = runStart + (runs[i+1] & Layout.RUN_LENGTH_MASK);
if (runLimit > mLen) {
runLimit = mLen;
}
boolean runIsRtl = (runs[i+1] & Layout.RUN_RTL_FLAG) != 0;
int segstart = runStart;
for (int j = mHasTabs ? runStart : runLimit; j <= runLimit; j++) {
int codept = 0;
Bitmap bm = null;
if (mHasTabs && j < runLimit) {
codept = mChars[j];
if (codept >= 0xd800 && codept < 0xdc00 && j + 1 < runLimit) {
codept = Character.codePointAt(mChars, j);
if (codept >= Layout.MIN_EMOJI && codept <= Layout.MAX_EMOJI) {
bm = Layout.EMOJI_FACTORY.getBitmapFromAndroidPua(codept);
} else if (codept > 0xffff) {
++j;
continue;
}
}
}
if (j == runLimit || codept == '\t' || bm != null) {
h += drawRun(c, segstart, j, runIsRtl, x+h, top, y, bottom,
i != lastRunIndex || j != mLen);
if (codept == '\t') {
h = mDir * nextTab(h * mDir);
} else if (bm != null) {
float bmAscent = ascent(j);
float bitmapHeight = bm.getHeight();
float scale = -bmAscent / bitmapHeight;
float width = bm.getWidth() * scale;
if (emojiRect == null) {
emojiRect = new RectF();
}
emojiRect.set(x + h, y + bmAscent,
x + h + width, y);
c.drawBitmap(bm, null, emojiRect, mPaint);
h += width;
j++;
}
segstart = j + 1;
}
}
}
}
/**
* Returns metrics information for the entire line.
*
* @param fmi receives font metrics information, can be null
* @return the signed width of the line
*/
float metrics(FontMetricsInt fmi) {
return measure(mLen, false, fmi);
}
/**
* Returns information about a position on the line.
*
* @param offset the line-relative character offset, between 0 and the
* line length, inclusive
* @param trailing true to measure the trailing edge of the character
* before offset, false to measure the leading edge of the character
* at offset.
* @param fmi receives metrics information about the requested
* character, can be null.
* @return the signed offset from the leading margin to the requested
* character edge.
*/
float measure(int offset, boolean trailing, FontMetricsInt fmi) {
int target = trailing ? offset - 1 : offset;
if (target < 0) {
return 0;
}
float h = 0;
if (!mHasTabs) {
if (mDirections == Layout.DIRS_ALL_LEFT_TO_RIGHT) {
return measureRun(0, offset, mLen, false, fmi);
}
if (mDirections == Layout.DIRS_ALL_RIGHT_TO_LEFT) {
return measureRun(0, offset, mLen, true, fmi);
}
}
char[] chars = mChars;
int[] runs = mDirections.mDirections;
for (int i = 0; i < runs.length; i += 2) {
int runStart = runs[i];
int runLimit = runStart + (runs[i+1] & Layout.RUN_LENGTH_MASK);
if (runLimit > mLen) {
runLimit = mLen;
}
boolean runIsRtl = (runs[i+1] & Layout.RUN_RTL_FLAG) != 0;
int segstart = runStart;
for (int j = mHasTabs ? runStart : runLimit; j <= runLimit; j++) {
int codept = 0;
Bitmap bm = null;
if (mHasTabs && j < runLimit) {
codept = chars[j];
if (codept >= 0xd800 && codept < 0xdc00 && j + 1 < runLimit) {
codept = Character.codePointAt(chars, j);
if (codept >= Layout.MIN_EMOJI && codept <= Layout.MAX_EMOJI) {
bm = Layout.EMOJI_FACTORY.getBitmapFromAndroidPua(codept);
} else if (codept > 0xffff) {
++j;
continue;
}
}
}
if (j == runLimit || codept == '\t' || bm != null) {
boolean inSegment = target >= segstart && target < j;
boolean advance = (mDir == Layout.DIR_RIGHT_TO_LEFT) == runIsRtl;
if (inSegment && advance) {
return h += measureRun(segstart, offset, j, runIsRtl, fmi);
}
float w = measureRun(segstart, j, j, runIsRtl, fmi);
h += advance ? w : -w;
if (inSegment) {
return h += measureRun(segstart, offset, j, runIsRtl, null);
}
if (codept == '\t') {
if (offset == j) {
return h;
}
h = mDir * nextTab(h * mDir);
if (target == j) {
return h;
}
}
if (bm != null) {
float bmAscent = ascent(j);
float wid = bm.getWidth() * -bmAscent / bm.getHeight();
h += mDir * wid;
j++;
}
segstart = j + 1;
}
}
}
return h;
}
/**
* Draws a unidirectional (but possibly multi-styled) run of text.
*
*
* @param c the canvas to draw on
* @param start the line-relative start
* @param limit the line-relative limit
* @param runIsRtl true if the run is right-to-left
* @param x the position of the run that is closest to the leading margin
* @param top the top of the line
* @param y the baseline
* @param bottom the bottom of the line
* @param needWidth true if the width value is required.
* @return the signed width of the run, based on the paragraph direction.
* Only valid if needWidth is true.
*/
private float drawRun(Canvas c, int start,
int limit, boolean runIsRtl, float x, int top, int y, int bottom,
boolean needWidth) {
if ((mDir == Layout.DIR_LEFT_TO_RIGHT) == runIsRtl) {
float w = -measureRun(start, limit, limit, runIsRtl, null);
handleRun(start, limit, limit, runIsRtl, c, x + w, top,
y, bottom, null, false);
return w;
}
return handleRun(start, limit, limit, runIsRtl, c, x, top,
y, bottom, null, needWidth);
}
/**
* Measures a unidirectional (but possibly multi-styled) run of text.
*
*
* @param start the line-relative start of the run
* @param offset the offset to measure to, between start and limit inclusive
* @param limit the line-relative limit of the run
* @param runIsRtl true if the run is right-to-left
* @param fmi receives metrics information about the requested
* run, can be null.
* @return the signed width from the start of the run to the leading edge
* of the character at offset, based on the run (not paragraph) direction
*/
private float measureRun(int start, int offset, int limit, boolean runIsRtl,
FontMetricsInt fmi) {
return handleRun(start, offset, limit, runIsRtl, null, 0, 0, 0, 0, fmi, true);
}
/**
* Walk the cursor through this line, skipping conjuncts and
* zero-width characters.
*
* This function cannot properly walk the cursor off the ends of the line
* since it does not know about any shaping on the previous/following line
* that might affect the cursor position. Callers must either avoid these
* situations or handle the result specially.
*
* @param cursor the starting position of the cursor, between 0 and the
* length of the line, inclusive
* @param toLeft true if the caret is moving to the left.
* @return the new offset. If it is less than 0 or greater than the length
* of the line, the previous/following line should be examined to get the
* actual offset.
*/
int getOffsetToLeftRightOf(int cursor, boolean toLeft) {
// 1) The caret marks the leading edge of a character. The character
// logically before it might be on a different level, and the active caret
// position is on the character at the lower level. If that character
// was the previous character, the caret is on its trailing edge.
// 2) Take this character/edge and move it in the indicated direction.
// This gives you a new character and a new edge.
// 3) This position is between two visually adjacent characters. One of
// these might be at a lower level. The active position is on the
// character at the lower level.
// 4) If the active position is on the trailing edge of the character,
// the new caret position is the following logical character, else it
// is the character.
int lineStart = 0;
int lineEnd = mLen;
boolean paraIsRtl = mDir == -1;
int[] runs = mDirections.mDirections;
int runIndex, runLevel = 0, runStart = lineStart, runLimit = lineEnd, newCaret = -1;
boolean trailing = false;
if (cursor == lineStart) {
runIndex = -2;
} else if (cursor == lineEnd) {
runIndex = runs.length;
} else {
// First, get information about the run containing the character with
// the active caret.
for (runIndex = 0; runIndex < runs.length; runIndex += 2) {
runStart = lineStart + runs[runIndex];
if (cursor >= runStart) {
runLimit = runStart + (runs[runIndex+1] & Layout.RUN_LENGTH_MASK);
if (runLimit > lineEnd) {
runLimit = lineEnd;
}
if (cursor < runLimit) {
runLevel = (runs[runIndex+1] >>> Layout.RUN_LEVEL_SHIFT) &
Layout.RUN_LEVEL_MASK;
if (cursor == runStart) {
// The caret is on a run boundary, see if we should
// use the position on the trailing edge of the previous
// logical character instead.
int prevRunIndex, prevRunLevel, prevRunStart, prevRunLimit;
int pos = cursor - 1;
for (prevRunIndex = 0; prevRunIndex < runs.length; prevRunIndex += 2) {
prevRunStart = lineStart + runs[prevRunIndex];
if (pos >= prevRunStart) {
prevRunLimit = prevRunStart +
(runs[prevRunIndex+1] & Layout.RUN_LENGTH_MASK);
if (prevRunLimit > lineEnd) {
prevRunLimit = lineEnd;
}
if (pos < prevRunLimit) {
prevRunLevel = (runs[prevRunIndex+1] >>> Layout.RUN_LEVEL_SHIFT)
& Layout.RUN_LEVEL_MASK;
if (prevRunLevel < runLevel) {
// Start from logically previous character.
runIndex = prevRunIndex;
runLevel = prevRunLevel;
runStart = prevRunStart;
runLimit = prevRunLimit;
trailing = true;
break;
}
}
}
}
}
break;
}
}
}
// caret might be == lineEnd. This is generally a space or paragraph
// separator and has an associated run, but might be the end of
// text, in which case it doesn't. If that happens, we ran off the
// end of the run list, and runIndex == runs.length. In this case,
// we are at a run boundary so we skip the below test.
if (runIndex != runs.length) {
boolean runIsRtl = (runLevel & 0x1) != 0;
boolean advance = toLeft == runIsRtl;
if (cursor != (advance ? runLimit : runStart) || advance != trailing) {
// Moving within or into the run, so we can move logically.
newCaret = getOffsetBeforeAfter(runIndex, runStart, runLimit,
runIsRtl, cursor, advance);
// If the new position is internal to the run, we're at the strong
// position already so we're finished.
if (newCaret != (advance ? runLimit : runStart)) {
return newCaret;
}
}
}
}
// If newCaret is -1, we're starting at a run boundary and crossing
// into another run. Otherwise we've arrived at a run boundary, and
// need to figure out which character to attach to. Note we might
// need to run this twice, if we cross a run boundary and end up at
// another run boundary.
while (true) {
boolean advance = toLeft == paraIsRtl;
int otherRunIndex = runIndex + (advance ? 2 : -2);
if (otherRunIndex >= 0 && otherRunIndex < runs.length) {
int otherRunStart = lineStart + runs[otherRunIndex];
int otherRunLimit = otherRunStart +
(runs[otherRunIndex+1] & Layout.RUN_LENGTH_MASK);
if (otherRunLimit > lineEnd) {
otherRunLimit = lineEnd;
}
int otherRunLevel = (runs[otherRunIndex+1] >>> Layout.RUN_LEVEL_SHIFT) &
Layout.RUN_LEVEL_MASK;
boolean otherRunIsRtl = (otherRunLevel & 1) != 0;
advance = toLeft == otherRunIsRtl;
if (newCaret == -1) {
newCaret = getOffsetBeforeAfter(otherRunIndex, otherRunStart,
otherRunLimit, otherRunIsRtl,
advance ? otherRunStart : otherRunLimit, advance);
if (newCaret == (advance ? otherRunLimit : otherRunStart)) {
// Crossed and ended up at a new boundary,
// repeat a second and final time.
runIndex = otherRunIndex;
runLevel = otherRunLevel;
continue;
}
break;
}
// The new caret is at a boundary.
if (otherRunLevel < runLevel) {
// The strong character is in the other run.
newCaret = advance ? otherRunStart : otherRunLimit;
}
break;
}
if (newCaret == -1) {
// We're walking off the end of the line. The paragraph
// level is always equal to or lower than any internal level, so
// the boundaries get the strong caret.
newCaret = advance ? mLen + 1 : -1;
break;
}
// Else we've arrived at the end of the line. That's a strong position.
// We might have arrived here by crossing over a run with no internal
// breaks and dropping out of the above loop before advancing one final
// time, so reset the caret.
// Note, we use '<=' below to handle a situation where the only run
// on the line is a counter-directional run. If we're not advancing,
// we can end up at the 'lineEnd' position but the caret we want is at
// the lineStart.
if (newCaret <= lineEnd) {
newCaret = advance ? lineEnd : lineStart;
}
break;
}
return newCaret;
}
/**
* Returns the next valid offset within this directional run, skipping
* conjuncts and zero-width characters. This should not be called to walk
* off the end of the line, since the returned values might not be valid
* on neighboring lines. If the returned offset is less than zero or
* greater than the line length, the offset should be recomputed on the
* preceding or following line, respectively.
*
* @param runIndex the run index
* @param runStart the start of the run
* @param runLimit the limit of the run
* @param runIsRtl true if the run is right-to-left
* @param offset the offset
* @param after true if the new offset should logically follow the provided
* offset
* @return the new offset
*/
private int getOffsetBeforeAfter(int runIndex, int runStart, int runLimit,
boolean runIsRtl, int offset, boolean after) {
if (runIndex < 0 || offset == (after ? mLen : 0)) {
// Walking off end of line. Since we don't know
// what cursor positions are available on other lines, we can't
// return accurate values. These are a guess.
if (after) {
return TextUtils.getOffsetAfter(mText, offset + mStart) - mStart;
}
return TextUtils.getOffsetBefore(mText, offset + mStart) - mStart;
}
TextPaint wp = mWorkPaint;
wp.set(mPaint);
int spanStart = runStart;
int spanLimit;
if (mSpanned == null) {
spanLimit = runLimit;
} else {
int target = after ? offset + 1 : offset;
int limit = mStart + runLimit;
while (true) {
spanLimit = mSpanned.nextSpanTransition(mStart + spanStart, limit,
MetricAffectingSpan.class) - mStart;
if (spanLimit >= target) {
break;
}
spanStart = spanLimit;
}
MetricAffectingSpan[] spans = mSpanned.getSpans(mStart + spanStart,
mStart + spanLimit, MetricAffectingSpan.class);
spans = TextUtils.removeEmptySpans(spans, mSpanned, MetricAffectingSpan.class);
if (spans.length > 0) {
ReplacementSpan replacement = null;
for (int j = 0; j < spans.length; j++) {
MetricAffectingSpan span = spans[j];
if (span instanceof ReplacementSpan) {
replacement = (ReplacementSpan)span;
} else {
span.updateMeasureState(wp);
}
}
if (replacement != null) {
// If we have a replacement span, we're moving either to
// the start or end of this span.
return after ? spanLimit : spanStart;
}
}
}
int flags = runIsRtl ? Paint.DIRECTION_RTL : Paint.DIRECTION_LTR;
int cursorOpt = after ? Paint.CURSOR_AFTER : Paint.CURSOR_BEFORE;
if (mCharsValid) {
return wp.getTextRunCursor(mChars, spanStart, spanLimit - spanStart,
flags, offset, cursorOpt);
} else {
return wp.getTextRunCursor(mText, mStart + spanStart,
mStart + spanLimit, flags, mStart + offset, cursorOpt) - mStart;
}
}
/**
* @param wp
*/
private static void expandMetricsFromPaint(FontMetricsInt fmi, TextPaint wp) {
final int previousTop = fmi.top;
final int previousAscent = fmi.ascent;
final int previousDescent = fmi.descent;
final int previousBottom = fmi.bottom;
final int previousLeading = fmi.leading;
wp.getFontMetricsInt(fmi);
updateMetrics(fmi, previousTop, previousAscent, previousDescent, previousBottom,
previousLeading);
}
static void updateMetrics(FontMetricsInt fmi, int previousTop, int previousAscent,
int previousDescent, int previousBottom, int previousLeading) {
fmi.top = Math.min(fmi.top, previousTop);
fmi.ascent = Math.min(fmi.ascent, previousAscent);
fmi.descent = Math.max(fmi.descent, previousDescent);
fmi.bottom = Math.max(fmi.bottom, previousBottom);
fmi.leading = Math.max(fmi.leading, previousLeading);
}
/**
* Utility function for measuring and rendering text. The text must
* not include a tab or emoji.
*
* @param wp the working paint
* @param start the start of the text
* @param end the end of the text
* @param runIsRtl true if the run is right-to-left
* @param c the canvas, can be null if rendering is not needed
* @param x the edge of the run closest to the leading margin
* @param top the top of the line
* @param y the baseline
* @param bottom the bottom of the line
* @param fmi receives metrics information, can be null
* @param needWidth true if the width of the run is needed
* @return the signed width of the run based on the run direction; only
* valid if needWidth is true
*/
private float handleText(TextPaint wp, int start, int end,
int contextStart, int contextEnd, boolean runIsRtl,
Canvas c, float x, int top, int y, int bottom,
FontMetricsInt fmi, boolean needWidth) {
// Get metrics first (even for empty strings or "0" width runs)
if (fmi != null) {
expandMetricsFromPaint(fmi, wp);
}
int runLen = end - start;
// No need to do anything if the run width is "0"
if (runLen == 0) {
return 0f;
}
float ret = 0;
int contextLen = contextEnd - contextStart;
if (needWidth || (c != null && (wp.bgColor != 0 || wp.underlineColor != 0 || runIsRtl))) {
int flags = runIsRtl ? Paint.DIRECTION_RTL : Paint.DIRECTION_LTR;
if (mCharsValid) {
ret = wp.getTextRunAdvances(mChars, start, runLen,
contextStart, contextLen, flags, null, 0);
} else {
int delta = mStart;
ret = wp.getTextRunAdvances(mText, delta + start,
delta + end, delta + contextStart, delta + contextEnd,
flags, null, 0);
}
}
if (c != null) {
if (runIsRtl) {
x -= ret;
}
if (wp.bgColor != 0) {
int previousColor = wp.getColor();
Paint.Style previousStyle = wp.getStyle();
wp.setColor(wp.bgColor);
wp.setStyle(Paint.Style.FILL);
c.drawRect(x, top, x + ret, bottom, wp);
wp.setStyle(previousStyle);
wp.setColor(previousColor);
}
if (wp.underlineColor != 0) {
// kStdUnderline_Offset = 1/9, defined in SkTextFormatParams.h
float underlineTop = y + wp.baselineShift + (1.0f / 9.0f) * wp.getTextSize();
int previousColor = wp.getColor();
Paint.Style previousStyle = wp.getStyle();
boolean previousAntiAlias = wp.isAntiAlias();
wp.setStyle(Paint.Style.FILL);
wp.setAntiAlias(true);
wp.setColor(wp.underlineColor);
c.drawRect(x, underlineTop, x + ret, underlineTop + wp.underlineThickness, wp);
wp.setStyle(previousStyle);
wp.setColor(previousColor);
wp.setAntiAlias(previousAntiAlias);
}
drawTextRun(c, wp, start, end, contextStart, contextEnd, runIsRtl,
x, y + wp.baselineShift);
}
return runIsRtl ? -ret : ret;
}
/**
* Utility function for measuring and rendering a replacement.
*
*
* @param replacement the replacement
* @param wp the work paint
* @param start the start of the run
* @param limit the limit of the run
* @param runIsRtl true if the run is right-to-left
* @param c the canvas, can be null if not rendering
* @param x the edge of the replacement closest to the leading margin
* @param top the top of the line
* @param y the baseline
* @param bottom the bottom of the line
* @param fmi receives metrics information, can be null
* @param needWidth true if the width of the replacement is needed
* @return the signed width of the run based on the run direction; only
* valid if needWidth is true
*/
private float handleReplacement(ReplacementSpan replacement, TextPaint wp,
int start, int limit, boolean runIsRtl, Canvas c,
float x, int top, int y, int bottom, FontMetricsInt fmi,
boolean needWidth) {
float ret = 0;
int textStart = mStart + start;
int textLimit = mStart + limit;
if (needWidth || (c != null && runIsRtl)) {
int previousTop = 0;
int previousAscent = 0;
int previousDescent = 0;
int previousBottom = 0;
int previousLeading = 0;
boolean needUpdateMetrics = (fmi != null);
if (needUpdateMetrics) {
previousTop = fmi.top;
previousAscent = fmi.ascent;
previousDescent = fmi.descent;
previousBottom = fmi.bottom;
previousLeading = fmi.leading;
}
ret = replacement.getSize(wp, mText, textStart, textLimit, fmi);
if (needUpdateMetrics) {
updateMetrics(fmi, previousTop, previousAscent, previousDescent, previousBottom,
previousLeading);
}
}
if (c != null) {
if (runIsRtl) {
x -= ret;
}
replacement.draw(c, mText, textStart, textLimit,
x, top, y, bottom, wp);
}
return runIsRtl ? -ret : ret;
}
/**
* Utility function for handling a unidirectional run. The run must not
* contain tabs or emoji but can contain styles.
*
*
* @param start the line-relative start of the run
* @param measureLimit the offset to measure to, between start and limit inclusive
* @param limit the limit of the run
* @param runIsRtl true if the run is right-to-left
* @param c the canvas, can be null
* @param x the end of the run closest to the leading margin
* @param top the top of the line
* @param y the baseline
* @param bottom the bottom of the line
* @param fmi receives metrics information, can be null
* @param needWidth true if the width is required
* @return the signed width of the run based on the run direction; only
* valid if needWidth is true
*/
private float handleRun(int start, int measureLimit,
int limit, boolean runIsRtl, Canvas c, float x, int top, int y,
int bottom, FontMetricsInt fmi, boolean needWidth) {
// Case of an empty line, make sure we update fmi according to mPaint
if (start == measureLimit) {
TextPaint wp = mWorkPaint;
wp.set(mPaint);
if (fmi != null) {
expandMetricsFromPaint(fmi, wp);
}
return 0f;
}
if (mSpanned == null) {
TextPaint wp = mWorkPaint;
wp.set(mPaint);
final int mlimit = measureLimit;
return handleText(wp, start, mlimit, start, limit, runIsRtl, c, x, top,
y, bottom, fmi, needWidth || mlimit < measureLimit);
}
mMetricAffectingSpanSpanSet.init(mSpanned, mStart + start, mStart + limit);
mCharacterStyleSpanSet.init(mSpanned, mStart + start, mStart + limit);
// Shaping needs to take into account context up to metric boundaries,
// but rendering needs to take into account character style boundaries.
// So we iterate through metric runs to get metric bounds,
// then within each metric run iterate through character style runs
// for the run bounds.
final float originalX = x;
for (int i = start, inext; i < measureLimit; i = inext) {
TextPaint wp = mWorkPaint;
wp.set(mPaint);
inext = mMetricAffectingSpanSpanSet.getNextTransition(mStart + i, mStart + limit) -
mStart;
int mlimit = Math.min(inext, measureLimit);
ReplacementSpan replacement = null;
for (int j = 0; j < mMetricAffectingSpanSpanSet.numberOfSpans; j++) {
// Both intervals [spanStarts..spanEnds] and [mStart + i..mStart + mlimit] are NOT
// empty by construction. This special case in getSpans() explains the >= & <= tests
if ((mMetricAffectingSpanSpanSet.spanStarts[j] >= mStart + mlimit) ||
(mMetricAffectingSpanSpanSet.spanEnds[j] <= mStart + i)) continue;
MetricAffectingSpan span = mMetricAffectingSpanSpanSet.spans[j];
if (span instanceof ReplacementSpan) {
replacement = (ReplacementSpan)span;
} else {
// We might have a replacement that uses the draw
// state, otherwise measure state would suffice.
span.updateDrawState(wp);
}
}
if (replacement != null) {
x += handleReplacement(replacement, wp, i, mlimit, runIsRtl, c, x, top, y,
bottom, fmi, needWidth || mlimit < measureLimit);
continue;
}
if (c == null) {
x += handleText(wp, i, mlimit, i, inext, runIsRtl, c, x, top,
y, bottom, fmi, needWidth || mlimit < measureLimit);
} else {
for (int j = i, jnext; j < mlimit; j = jnext) {
jnext = mCharacterStyleSpanSet.getNextTransition(mStart + j, mStart + mlimit) -
mStart;
wp.set(mPaint);
for (int k = 0; k < mCharacterStyleSpanSet.numberOfSpans; k++) {
// Intentionally using >= and <= as explained above
if ((mCharacterStyleSpanSet.spanStarts[k] >= mStart + jnext) ||
(mCharacterStyleSpanSet.spanEnds[k] <= mStart + j)) continue;
CharacterStyle span = mCharacterStyleSpanSet.spans[k];
span.updateDrawState(wp);
}
x += handleText(wp, j, jnext, i, inext, runIsRtl, c, x,
top, y, bottom, fmi, needWidth || jnext < measureLimit);
}
}
}
return x - originalX;
}
/**
* Render a text run with the set-up paint.
*
* @param c the canvas
* @param wp the paint used to render the text
* @param start the start of the run
* @param end the end of the run
* @param contextStart the start of context for the run
* @param contextEnd the end of the context for the run
* @param runIsRtl true if the run is right-to-left
* @param x the x position of the left edge of the run
* @param y the baseline of the run
*/
private void drawTextRun(Canvas c, TextPaint wp, int start, int end,
int contextStart, int contextEnd, boolean runIsRtl, float x, int y) {
int flags = runIsRtl ? Canvas.DIRECTION_RTL : Canvas.DIRECTION_LTR;
if (mCharsValid) {
int count = end - start;
int contextCount = contextEnd - contextStart;
c.drawTextRun(mChars, start, count, contextStart, contextCount,
x, y, flags, wp);
} else {
int delta = mStart;
c.drawTextRun(mText, delta + start, delta + end,
delta + contextStart, delta + contextEnd, x, y, flags, wp);
}
}
/**
* Returns the ascent of the text at start. This is used for scaling
* emoji.
*
* @param pos the line-relative position
* @return the ascent of the text at start
*/
float ascent(int pos) {
if (mSpanned == null) {
return mPaint.ascent();
}
pos += mStart;
MetricAffectingSpan[] spans = mSpanned.getSpans(pos, pos + 1, MetricAffectingSpan.class);
if (spans.length == 0) {
return mPaint.ascent();
}
TextPaint wp = mWorkPaint;
wp.set(mPaint);
for (MetricAffectingSpan span : spans) {
span.updateMeasureState(wp);
}
return wp.ascent();
}
/**
* Returns the next tab position.
*
* @param h the (unsigned) offset from the leading margin
* @return the (unsigned) tab position after this offset
*/
float nextTab(float h) {
if (mTabs != null) {
return mTabs.nextTab(h);
}
return TabStops.nextDefaultStop(h, TAB_INCREMENT);
}
private static final int TAB_INCREMENT = 20;
}