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Separate additional penalty for last line with hyphen

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A recent change added a penalty for a hyphen at the last line break,
which is visually undesirable. However, the penalty was assessed to
"widthScore", which broke the assumption (used for another
optimization) that widthScore increases monotonically. This patch
separates the penalty into a different parameter, restoring the
validity of the monotonicity assumption.

Bug: 22066119
Change-Id: I6a47a350ef3ceee2f00ee430d6954d0c307227f0
This commit is contained in:
Raph Levien 2015-06-24 12:59:18 -07:00
parent 072167f797
commit e5cb2f787c
1 changed files with 10 additions and 2 deletions
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12
engine/src/flutter/libs/minikin/LineBreaker.cpp
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@ -353,12 +353,17 @@ void LineBreaker::computeBreaksOptimal(bool isRectangle) {
float delta = mCandidates[j].preBreak - leftEdge;
// compute width score for line
// Note: the "bestHope" optimization makes the assumption that, when delta is
// non-negative, widthScore will increase monotonically as successive candidate
// breaks are considered.
float widthScore = 0.0f;
float additionalPenalty = 0.0f;
if (delta < 0) {
widthScore = SCORE_OVERFULL;
} else if (atEnd && mStrategy != kBreakStrategy_Balanced) {
// increase penalty for hyphen on last line
widthScore = LAST_LINE_PENALTY_MULTIPLIER * mCandidates[j].penalty;
additionalPenalty = LAST_LINE_PENALTY_MULTIPLIER * mCandidates[j].penalty;
} else {
widthScore = delta * delta;
}
@ -369,7 +374,7 @@ void LineBreaker::computeBreaksOptimal(bool isRectangle) {
bestHope = widthScore;
}
float score = jScore + widthScore;
float score = jScore + widthScore + additionalPenalty;
if (score <= best) {
best = score;
bestPrev = j;
@ -378,6 +383,9 @@ void LineBreaker::computeBreaksOptimal(bool isRectangle) {
mCandidates[i].score = best + mCandidates[i].penalty + mLinePenalty;
mCandidates[i].prev = bestPrev;
mCandidates[i].lineNumber = mCandidates[bestPrev].lineNumber + 1;
#ifdef VERBOSE_DEBUG
ALOGD("break %d: score=%g, prev=%d", i, mCandidates[i].score, mCandidates[i].prev);
#endif
}
finishBreaksOptimal();
}