/**
* 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;
}
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);
}
// Only draw hyphen on last run in line
if (jnext < mLen) {
wp.setHyphenEdit(0);
}
x +=
handleText(
wp,
j,
jnext,
i,
inext,
runIsRtl,
c,
x,
top,
y,
bottom,
fmi,
needWidth || jnext < measureLimit);
}
}
return x - originalX;
}
