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Optimize: Use measureText instead of doLayout.

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With this CL, measureText is used for getRunAdvance,
getOffsetForAdvance and line breaking.

Bug: 24505153
Change-Id: Ib699f6b1391b46537736fc274cdb41686586b550
This commit is contained in:
Keisuke Kuroyanagi
2016-02-18 11:35:42 -08:00
parent 72ab39455f
commit 761218bce9
3 changed files with 25 additions and 24 deletions
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5
engine/src/flutter/include/minikin/Measurement.h
View File

@@ -21,9 +21,10 @@
namespace android {
float getRunAdvance(Layout& layout, const uint16_t* buf, size_t start, size_t count, size_t offset);
float getRunAdvance(const float* advances, const uint16_t* buf, size_t start, size_t count,
size_t offset);
size_t getOffsetForAdvance(Layout& layout, const uint16_t* buf, size_t start, size_t count,
size_t getOffsetForAdvance(const float* advances, const uint16_t* buf, size_t start, size_t count,
float advance);
}

24
engine/src/flutter/libs/minikin/LineBreaker.cpp
View File

@@ -122,17 +122,13 @@ static bool isLineBreakingHyphen(uint16_t c) {
// to addCandidate.
float LineBreaker::addStyleRun(MinikinPaint* paint, const FontCollection* typeface,
FontStyle style, size_t start, size_t end, bool isRtl) {
Layout layout; // performance TODO: move layout to self object to reduce allocation cost?
float width = 0.0f;
int bidiFlags = isRtl ? kBidi_Force_RTL : kBidi_Force_LTR;
float hyphenPenalty = 0.0;
if (paint != nullptr) {
layout.setFontCollection(typeface);
layout.doLayout(mTextBuf.data(), start, end - start, mTextBuf.size(), bidiFlags, style,
*paint);
layout.getAdvances(mCharWidths.data() + start);
width = layout.getAdvance();
width = Layout::measureText(mTextBuf.data(), start, end - start, mTextBuf.size(), bidiFlags,
style, *paint, typeface, mCharWidths.data() + start);
// a heuristic that seems to perform well
hyphenPenalty = 0.5 * paint->size * paint->scaleX * mLineWidths.getLineWidth(0);
@@ -192,13 +188,17 @@ float LineBreaker::addStyleRun(MinikinPaint* paint, const FontCollection* typefa
uint8_t hyph = mHyphBuf[j - wordStart];
if (hyph) {
paint->hyphenEdit = hyph;
layout.doLayout(mTextBuf.data(), lastBreak, j - lastBreak,
mTextBuf.size(), bidiFlags, style, *paint);
ParaWidth hyphPostBreak = lastBreakWidth + layout.getAdvance();
const float firstPartWidth = Layout::measureText(mTextBuf.data(),
lastBreak, j - lastBreak, mTextBuf.size(), bidiFlags, style,
*paint, typeface, nullptr);
ParaWidth hyphPostBreak = lastBreakWidth + firstPartWidth;
paint->hyphenEdit = 0;
layout.doLayout(mTextBuf.data(), j, afterWord - j,
mTextBuf.size(), bidiFlags, style, *paint);
ParaWidth hyphPreBreak = postBreak - layout.getAdvance();
const float secondPartWith = Layout::measureText(mTextBuf.data(), j,
afterWord - j, mTextBuf.size(), bidiFlags, style, *paint,
typeface, nullptr);
ParaWidth hyphPreBreak = postBreak - secondPartWith;
addWordBreak(j, hyphPreBreak, hyphPostBreak, hyphenPenalty, hyph);
}
}

20
engine/src/flutter/libs/minikin/Measurement.cpp
View File

@@ -28,26 +28,26 @@ namespace android {
// These could be considered helper methods of layout, but need only be loosely coupled, so
// are separate.
static float getRunAdvance(Layout& layout, const uint16_t* buf, size_t layoutStart, size_t start,
size_t count, size_t offset) {
static float getRunAdvance(const float* advances, const uint16_t* buf, size_t layoutStart,
size_t start, size_t count, size_t offset) {
float advance = 0.0f;
size_t lastCluster = start;
float clusterWidth = 0.0f;
for (size_t i = start; i < offset; i++) {
float charAdvance = layout.getCharAdvance(i - layoutStart);
float charAdvance = advances[i - layoutStart];
if (charAdvance != 0.0f) {
advance += charAdvance;
lastCluster = i;
clusterWidth = charAdvance;
}
}
if (offset < start + count && layout.getCharAdvance(offset - layoutStart) == 0.0f) {
if (offset < start + count && advances[offset - layoutStart] == 0.0f) {
// In the middle of a cluster, distribute width of cluster so that each grapheme cluster
// gets an equal share.
// TODO: get caret information out of font when that's available
size_t nextCluster;
for (nextCluster = offset + 1; nextCluster < start + count; nextCluster++) {
if (layout.getCharAdvance(nextCluster - layoutStart) != 0.0f) break;
if (advances[nextCluster - layoutStart] != 0.0f) break;
}
int numGraphemeClusters = 0;
int numGraphemeClustersAfter = 0;
@@ -67,9 +67,9 @@ static float getRunAdvance(Layout& layout, const uint16_t* buf, size_t layoutSta
return advance;
}
float getRunAdvance(Layout& layout, const uint16_t* buf, size_t start, size_t count,
float getRunAdvance(const float* advances, const uint16_t* buf, size_t start, size_t count,
size_t offset) {
return getRunAdvance(layout, buf, start, start, count, offset);
return getRunAdvance(advances, buf, start, start, count, offset);
}
/**
@@ -80,7 +80,7 @@ float getRunAdvance(Layout& layout, const uint16_t* buf, size_t start, size_t co
* The actual implementation fast-forwards through clusters to get "close", then does a finer-grain
* search within the cluster and grapheme breaks.
*/
size_t getOffsetForAdvance(Layout& layout, const uint16_t* buf, size_t start, size_t count,
size_t getOffsetForAdvance(const float* advances, const uint16_t* buf, size_t start, size_t count,
float advance) {
float x = 0.0f, xLastClusterStart = 0.0f, xSearchStart = 0.0f;
size_t lastClusterStart = start, searchStart = start;
@@ -89,7 +89,7 @@ size_t getOffsetForAdvance(Layout& layout, const uint16_t* buf, size_t start, si
searchStart = lastClusterStart;
xSearchStart = xLastClusterStart;
}
float width = layout.getCharAdvance(i - start);
float width = advances[i - start];
if (width != 0.0f) {
lastClusterStart = i;
xLastClusterStart = x;
@@ -104,7 +104,7 @@ size_t getOffsetForAdvance(Layout& layout, const uint16_t* buf, size_t start, si
for (size_t i = searchStart; i <= start + count; i++) {
if (GraphemeBreak::isGraphemeBreak(buf, start, count, i)) {
// "getRunAdvance(layout, buf, start, count, i) - advance" but more efficient
float delta = getRunAdvance(layout, buf, start, searchStart, count - searchStart, i)
float delta = getRunAdvance(advances, buf, start, searchStart, count - searchStart, i)
+ xSearchStart - advance;
if (std::abs(delta) < bestDist) {