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Support for context in API

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This patch completes support for adding context for complex script
layout, for example when a string with joins straddles two spans.

Part of the fix for 15431028: "Properly support context for joining
scripts (Minikin)"

Change-Id: I65b0833be92eb477aa531bbef0ac6eddeb3a962a
This commit is contained in:
Raph Levien
2014-06-04 15:20:37 -07:00
parent ddcdc08c7c
commit 06dec08ca2
2 changed files with 15 additions and 22 deletions
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2
engine/src/flutter/include/minikin/Layout.h
View File

@@ -105,7 +105,7 @@ private:
// Lay out a single bidi run // Lay out a single bidi run
void doLayoutRunCached(const uint16_t* buf, size_t start, size_t count, size_t bufSize, void doLayoutRunCached(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
bool isRtl, LayoutContext* ctx); bool isRtl, LayoutContext* ctx, size_t dstStart);
// Lay out a single word // Lay out a single word
void doLayoutWord(const uint16_t* buf, size_t start, size_t count, size_t bufSize, void doLayoutWord(const uint16_t* buf, size_t start, size_t count, size_t bufSize,

35
engine/src/flutter/libs/minikin/Layout.cpp
View File

@@ -485,17 +485,6 @@ void Layout::doLayout(const uint16_t* buf, size_t nchars) {
doLayout(buf, 0, nchars, nchars, mCssString); doLayout(buf, 0, nchars, nchars, mCssString);
} }
// TODO: use some standard implementation
template<typename T>
static T mymin(const T& a, const T& b) {
return a < b ? a : b;
}
template<typename T>
static T mymax(const T& a, const T& b) {
return a > b ? a : b;
}
static void clearHbFonts(LayoutContext* ctx) { static void clearHbFonts(LayoutContext* ctx) {
for (size_t i = 0; i < ctx->hbFonts.size(); i++) { for (size_t i = 0; i < ctx->hbFonts.size(); i++) {
hb_font_destroy(ctx->hbFonts[i]); hb_font_destroy(ctx->hbFonts[i]);
@@ -503,7 +492,6 @@ static void clearHbFonts(LayoutContext* ctx) {
ctx->hbFonts.clear(); ctx->hbFonts.clear();
} }
// TODO: API should probably take context
void Layout::doLayout(const uint16_t* buf, size_t start, size_t count, size_t bufSize, void Layout::doLayout(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
const string& css) { const string& css) {
AutoMutex _l(gMinikinLock); AutoMutex _l(gMinikinLock);
@@ -560,9 +548,14 @@ void Layout::doLayout(const uint16_t* buf, size_t start, size_t count, size_t bu
// skip the invalid run // skip the invalid run
continue; continue;
} }
isRtl = (runDir == UBIDI_RTL); int32_t endRun = std::min(startRun + lengthRun, int32_t(start + count));
// TODO: min/max with context startRun = std::max(startRun, int32_t(start));
doLayoutRunCached(buf, startRun, lengthRun, bufSize, isRtl, &ctx); lengthRun = endRun - startRun;
if (lengthRun > 0) {
isRtl = (runDir == UBIDI_RTL);
doLayoutRunCached(buf, startRun, lengthRun, bufSize, isRtl, &ctx,
start);
}
} }
} }
} else { } else {
@@ -574,22 +567,22 @@ void Layout::doLayout(const uint16_t* buf, size_t start, size_t count, size_t bu
} }
} }
if (doSingleRun) { if (doSingleRun) {
doLayoutRunCached(buf, start, count, bufSize, isRtl, &ctx); doLayoutRunCached(buf, start, count, bufSize, isRtl, &ctx, start);
} }
clearHbFonts(&ctx); clearHbFonts(&ctx);
} }
void Layout::doLayoutRunCached(const uint16_t* buf, size_t start, size_t count, size_t bufSize, void Layout::doLayoutRunCached(const uint16_t* buf, size_t start, size_t count, size_t bufSize,
bool isRtl, LayoutContext* ctx) { bool isRtl, LayoutContext* ctx, size_t dstStart) {
if (!isRtl) { if (!isRtl) {
// left to right // left to right
size_t wordstart = start == bufSize ? start : getPrevWordBreak(buf, start + 1); size_t wordstart = start == bufSize ? start : getPrevWordBreak(buf, start + 1);
size_t wordend; size_t wordend;
for (size_t iter = start; iter < start + count; iter = wordend) { for (size_t iter = start; iter < start + count; iter = wordend) {
wordend = getNextWordBreak(buf, iter, bufSize); wordend = getNextWordBreak(buf, iter, bufSize);
size_t wordcount = mymin(start + count, wordend) - iter; size_t wordcount = std::min(start + count, wordend) - iter;
doLayoutWord(buf + wordstart, iter - wordstart, wordcount, wordend - wordstart, doLayoutWord(buf + wordstart, iter - wordstart, wordcount, wordend - wordstart,
isRtl, ctx, iter); isRtl, ctx, iter - dstStart);
wordstart = wordend; wordstart = wordend;
} }
} else { } else {
@@ -599,9 +592,9 @@ void Layout::doLayoutRunCached(const uint16_t* buf, size_t start, size_t count,
size_t wordend = end == 0 ? 0 : getNextWordBreak(buf, end - 1, bufSize); size_t wordend = end == 0 ? 0 : getNextWordBreak(buf, end - 1, bufSize);
for (size_t iter = end; iter > start; iter = wordstart) { for (size_t iter = end; iter > start; iter = wordstart) {
wordstart = getPrevWordBreak(buf, iter); wordstart = getPrevWordBreak(buf, iter);
size_t bufStart = mymax(start, wordstart); size_t bufStart = std::max(start, wordstart);
doLayoutWord(buf + wordstart, bufStart - wordstart, iter - bufStart, doLayoutWord(buf + wordstart, bufStart - wordstart, iter - bufStart,
wordend - wordstart, isRtl, ctx, bufStart); wordend - wordstart, isRtl, ctx, bufStart - dstStart);
wordend = wordstart; wordend = wordstart;
} }
} }