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[SkSVGDevice] Fix whitespace text handling

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SVG ignores leading/trailing whitespace and consolidates mid-text
(http://www.w3.org/TR/SVG/text.html#WhiteSpace). This can cause our
x/y position indices to get out of whack.

Implement a text builder which is SVG whitespace-munging-aware and
performs the needed x/y position list adjustments.

R=reed@google.com,mtklein@google.com

Review URL: https://codereview.chromium.org/928583003
This commit is contained in:
fmalita 2015-02-19 18:44:51 -08:00 committed by Commit bot
parent 0c2da0c99f
commit 8974774c32
1 changed files with 141 additions and 86 deletions
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227
src/svg/SkSVGDevice.cpp
View File

@ -101,71 +101,6 @@ static SkString svg_transform(const SkMatrix& t) {
return tstr;
}
static void append_escaped_unichar(SkUnichar c, SkString* text) {
switch(c) {
case '&':
text->append("&");
break;
case '"':
text->append(""");
break;
case '\'':
text->append("'");
break;
case '<':
text->append("&lt;");
break;
case '>':
text->append("&gt;");
break;
default:
text->appendUnichar(c);
break;
}
}
static SkString svg_text(const void* text, size_t byteLen, const SkPaint& paint) {
SkString svgText;
int count = paint.countText(text, byteLen);
switch(paint.getTextEncoding()) {
case SkPaint::kGlyphID_TextEncoding: {
SkASSERT(count * sizeof(uint16_t) == byteLen);
SkAutoSTArray<64, SkUnichar> unichars(count);
paint.glyphsToUnichars((const uint16_t*)text, count, unichars.get());
for (int i = 0; i < count; ++i) {
append_escaped_unichar(unichars[i], &svgText);
}
} break;
case SkPaint::kUTF8_TextEncoding: {
const char* c8 = reinterpret_cast<const char*>(text);
for (int i = 0; i < count; ++i) {
append_escaped_unichar(SkUTF8_NextUnichar(&c8), &svgText);
}
SkASSERT(reinterpret_cast<const char*>(text) + byteLen == c8);
} break;
case SkPaint::kUTF16_TextEncoding: {
const uint16_t* c16 = reinterpret_cast<const uint16_t*>(text);
for (int i = 0; i < count; ++i) {
append_escaped_unichar(SkUTF16_NextUnichar(&c16), &svgText);
}
SkASSERT(SkIsAlign2(byteLen));
SkASSERT(reinterpret_cast<const uint16_t*>(text) + (byteLen / 2) == c16);
} break;
case SkPaint::kUTF32_TextEncoding: {
SkASSERT(count * sizeof(uint32_t) == byteLen);
const uint32_t* c32 = reinterpret_cast<const uint32_t*>(text);
for (int i = 0; i < count; ++i) {
append_escaped_unichar(c32[i], &svgText);
}
} break;
default:
SkFAIL("unknown text encoding");
}
return svgText;
}
uint32_t hash_family_string(const SkString& family) {
// This is a lame hash function, but we don't really expect to see more than 1-2
// family names under normal circumstances.
@ -180,6 +115,136 @@ struct Resources {
SkString fClip;
};
class SVGTextBuilder : SkNoncopyable {
public:
SVGTextBuilder(const void* text, size_t byteLen, const SkPaint& paint, const SkPoint& offset,
unsigned scalarsPerPos, const SkScalar pos[] = NULL)
: fOffset(offset)
, fScalarsPerPos(scalarsPerPos)
, fPos(pos)
, fLastCharWasWhitespace(true) // start off in whitespace mode to strip all leading space
{
SkASSERT(scalarsPerPos <= 2);
SkASSERT(scalarsPerPos == 0 || SkToBool(pos));
int count = paint.countText(text, byteLen);
switch(paint.getTextEncoding()) {
case SkPaint::kGlyphID_TextEncoding: {
SkASSERT(count * sizeof(uint16_t) == byteLen);
SkAutoSTArray<64, SkUnichar> unichars(count);
paint.glyphsToUnichars((const uint16_t*)text, count, unichars.get());
for (int i = 0; i < count; ++i) {
this->appendUnichar(unichars[i]);
}
} break;
case SkPaint::kUTF8_TextEncoding: {
const char* c8 = reinterpret_cast<const char*>(text);
for (int i = 0; i < count; ++i) {
this->appendUnichar(SkUTF8_NextUnichar(&c8));
}
SkASSERT(reinterpret_cast<const char*>(text) + byteLen == c8);
} break;
case SkPaint::kUTF16_TextEncoding: {
const uint16_t* c16 = reinterpret_cast<const uint16_t*>(text);
for (int i = 0; i < count; ++i) {
this->appendUnichar(SkUTF16_NextUnichar(&c16));
}
SkASSERT(SkIsAlign2(byteLen));
SkASSERT(reinterpret_cast<const uint16_t*>(text) + (byteLen / 2) == c16);
} break;
case SkPaint::kUTF32_TextEncoding: {
SkASSERT(count * sizeof(uint32_t) == byteLen);
const uint32_t* c32 = reinterpret_cast<const uint32_t*>(text);
for (int i = 0; i < count; ++i) {
this->appendUnichar(c32[i]);
}
} break;
default:
SkFAIL("unknown text encoding");
}
if (scalarsPerPos < 2) {
SkASSERT(fPosY.isEmpty());
fPosY.appendScalar(offset.y()); // DrawText or DrawPosTextH (fixed Y).
}
if (scalarsPerPos < 1) {
SkASSERT(fPosX.isEmpty());
fPosX.appendScalar(offset.x()); // DrawText (X also fixed).
}
}
const SkString& text() const { return fText; }
const SkString& posX() const { return fPosX; }
const SkString& posY() const { return fPosY; }
private:
void appendUnichar(SkUnichar c) {
bool discardPos = false;
bool isWhitespace = false;
switch(c) {
case ' ':
case '\t':
// consolidate whitespace to match SVG's xml:space=default munging
// (http://www.w3.org/TR/SVG/text.html#WhiteSpace)
if (fLastCharWasWhitespace) {
discardPos = true;
} else {
fText.appendUnichar(c);
}
isWhitespace = true;
break;
case '\0':
// SkPaint::glyphsToUnichars() returns \0 for inconvertible glyphs, but these
// are not legal XML characters (http://www.w3.org/TR/REC-xml/#charsets)
discardPos = true;
isWhitespace = fLastCharWasWhitespace; // preserve whitespace consolidation
break;
case '&':
fText.append("&amp;");
break;
case '"':
fText.append("&quot;");
break;
case '\'':
fText.append("&apos;");
break;
case '<':
fText.append("&lt;");
break;
case '>':
fText.append("&gt;");
break;
default:
fText.appendUnichar(c);
break;
}
this->advancePos(discardPos);
fLastCharWasWhitespace = isWhitespace;
}
void advancePos(bool discard) {
if (!discard && fScalarsPerPos > 0) {
fPosX.appendf("%.8g, ", fOffset.x() + fPos[0]);
if (fScalarsPerPos > 1) {
SkASSERT(fScalarsPerPos == 2);
fPosY.appendf("%.8g, ", fOffset.y() + fPos[1]);
}
}
fPos += fScalarsPerPos;
}
const SkPoint& fOffset;
const unsigned fScalarsPerPos;
const SkScalar* fPos;
SkString fText, fPosX, fPosY;
bool fLastCharWasWhitespace;
};
}
// For now all this does is serve unique serial IDs, but it will eventually evolve to track
@ -585,9 +650,11 @@ void SkSVGDevice::drawText(const SkDraw& draw, const void* text, size_t len,
SkScalar x, SkScalar y, const SkPaint& paint) {
AutoElement elem("text", fWriter, fResourceBucket, draw, paint);
elem.addTextAttributes(paint);
elem.addAttribute("x", x);
elem.addAttribute("y", y);
elem.addText(svg_text(text, len, paint));
SVGTextBuilder builder(text, len, paint, SkPoint::Make(x, y), 0);
elem.addAttribute("x", builder.posX());
elem.addAttribute("y", builder.posY());
elem.addText(builder.text());
}
void SkSVGDevice::drawPosText(const SkDraw& draw, const void* text, size_t len,
@ -598,23 +665,10 @@ void SkSVGDevice::drawPosText(const SkDraw& draw, const void* text, size_t len,
AutoElement elem("text", fWriter, fResourceBucket, draw, paint);
elem.addTextAttributes(paint);
SkString xStr;
SkString yStr;
for (int i = 0; i < paint.countText(text, len); ++i) {
xStr.appendf("%.8g, ", offset.x() + pos[i * scalarsPerPos]);
if (scalarsPerPos == 2) {
yStr.appendf("%.8g, ", offset.y() + pos[i * scalarsPerPos + 1]);
}
}
if (scalarsPerPos != 2) {
yStr.appendScalar(offset.y());
}
elem.addAttribute("x", xStr);
elem.addAttribute("y", yStr);
elem.addText(svg_text(text, len, paint));
SVGTextBuilder builder(text, len, paint, offset, scalarsPerPos, pos);
elem.addAttribute("x", builder.posX());
elem.addAttribute("y", builder.posY());
elem.addText(builder.text());
}
void SkSVGDevice::drawTextOnPath(const SkDraw&, const void* text, size_t len, const SkPath& path,
@ -648,7 +702,8 @@ void SkSVGDevice::drawTextOnPath(const SkDraw&, const void* text, size_t len, co
paint.getTextAlign() == SkPaint::kCenter_Align ? "50%" : "100%");
}
textPathElement.addText(svg_text(text, len, paint));
SVGTextBuilder builder(text, len, paint, SkPoint::Make(0, 0), 0);
textPathElement.addText(builder.text());
}
}
}