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|
/*
* Copyright 2009, The Android Open Source Project
* Copyright (C) 2006 Apple Computer, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "EmojiFont.h"
#include "Font.h"
#include "FontData.h"
#include "FontFallbackList.h"
#include "GraphicsContext.h"
#include "GlyphBuffer.h"
#include "IntRect.h"
#include "NotImplemented.h"
#include "PlatformGraphicsContext.h"
#include "SkCanvas.h"
#include "SkColorFilter.h"
#include "SkLayerDrawLooper.h"
#include "SkPaint.h"
#include "SkTemplates.h"
#include "SkTypeface.h"
#include "SkUtils.h"
#include "TextRun.h"
#ifdef SUPPORT_COMPLEX_SCRIPTS
#include "HarfbuzzSkia.h"
#include <unicode/normlzr.h>
#include <unicode/uchar.h>
#include <wtf/OwnArrayPtr.h>
#include <wtf/OwnPtr.h>
#include <wtf/PassOwnArrayPtr.h>
#include <wtf/PassOwnPtr.h>
#include <wtf/unicode/CharacterNames.h>
#include <wtf/unicode/Unicode.h>
#endif
using namespace android;
namespace WebCore {
typedef std::pair<int, float> FallbackFontKey;
typedef HashMap<FallbackFontKey, FontPlatformData*> FallbackHash;
static void updateForFont(SkPaint* paint, const SimpleFontData* font) {
font->platformData().setupPaint(paint);
paint->setTextEncoding(SkPaint::kGlyphID_TextEncoding);
}
static SkPaint* setupFill(SkPaint* paint, GraphicsContext* gc,
const SimpleFontData* font) {
gc->setupFillPaint(paint);
updateForFont(paint, font);
return paint;
}
static SkPaint* setupStroke(SkPaint* paint, GraphicsContext* gc,
const SimpleFontData* font) {
gc->setupStrokePaint(paint);
updateForFont(paint, font);
return paint;
}
static bool setupForText(SkPaint* paint, GraphicsContext* gc,
const SimpleFontData* font) {
int mode = gc->textDrawingMode() & (TextModeFill | TextModeStroke);
if (!mode)
return false;
paint->setVerticalText(font->platformData().orientation() == Vertical);
FloatSize shadowOffset;
float shadowBlur;
Color shadowColor;
ColorSpace shadowColorSpace;
bool hasShadow = gc->getShadow(shadowOffset, shadowBlur, shadowColor, shadowColorSpace);
bool hasBothStrokeAndFill =
(mode & (TextModeStroke | TextModeFill)) == (TextModeStroke | TextModeFill);
if (hasShadow || hasBothStrokeAndFill) {
SkLayerDrawLooper* looper = new SkLayerDrawLooper;
paint->setLooper(looper)->unref();
// The layerDrawLooper uses at the root paint to determine the text
// encoding so we need to make sure it is properly configured.
updateForFont(paint, font);
// Specify the behavior of the looper
SkLayerDrawLooper::LayerInfo info;
info.fPaintBits = SkLayerDrawLooper::kEntirePaint_Bits;
info.fColorMode = SkXfermode::kSrc_Mode;
info.fFlagsMask = SkPaint::kAllFlags;
// The paint is only valid until the looper receives another call to
// addLayer(). Therefore, we must cache certain state for later use.
bool hasFillPaint = false;
bool hasStrokePaint = false;
SkScalar strokeWidth;
if ((mode & TextModeStroke) && gc->willStroke()) {
strokeWidth = setupStroke(looper->addLayer(info), gc, font)->getStrokeWidth();
hasStrokePaint = true;
}
if ((mode & TextModeFill) && gc->willFill()) {
setupFill(looper->addLayer(info), gc, font);
hasFillPaint = true;
}
if (hasShadow) {
SkPaint shadowPaint;
SkPoint offset;
if (gc->setupShadowPaint(&shadowPaint, &offset)) {
// add an offset to the looper when creating a shadow layer
info.fOffset.set(offset.fX, offset.fY);
SkPaint* p = looper->addLayer(info);
*p = shadowPaint;
// Currently, only GraphicsContexts associated with the
// HTMLCanvasElement have shadows ignore transforms set. This
// allows us to distinguish between CSS and Canvas shadows which
// have different rendering specifications.
if (gc->shadowsIgnoreTransforms()) {
SkColorFilter* cf = SkColorFilter::CreateModeFilter(p->getColor(),
SkXfermode::kSrcIn_Mode);
p->setColorFilter(cf)->unref();
} else { // in CSS
p->setShader(NULL);
}
if (hasStrokePaint && !hasFillPaint) {
// stroke the shadow if we have stroke but no fill
p->setStyle(SkPaint::kStroke_Style);
p->setStrokeWidth(strokeWidth);
}
updateForFont(p, font);
}
}
} else if (mode & TextModeFill) {
(void)setupFill(paint, gc, font);
} else if (mode & TextModeStroke) {
(void)setupStroke(paint, gc, font);
} else {
return false;
}
return true;
}
bool Font::canReturnFallbackFontsForComplexText()
{
return false;
}
bool Font::canExpandAroundIdeographsInComplexText()
{
return false;
}
void Font::drawGlyphs(GraphicsContext* gc, const SimpleFontData* font,
const GlyphBuffer& glyphBuffer, int from, int numGlyphs,
const FloatPoint& point) const
{
// compile-time assert
SkASSERT(sizeof(GlyphBufferGlyph) == sizeof(uint16_t));
SkPaint paint;
if (!setupForText(&paint, gc, font)) {
return;
}
SkScalar x = SkFloatToScalar(point.x());
SkScalar y = SkFloatToScalar(point.y());
const GlyphBufferGlyph* glyphs = glyphBuffer.glyphs(from);
const GlyphBufferAdvance* adv = glyphBuffer.advances(from);
SkAutoSTMalloc<32, SkPoint> storage(numGlyphs), storage2(numGlyphs), storage3(numGlyphs);
SkPoint* pos = storage.get();
SkCanvas* canvas = gc->platformContext()->mCanvas;
/* We need an array of [x,y,x,y,x,y,...], but webkit is giving us
point.xy + [width, height, width, height, ...], so we have to convert
*/
if (font->platformData().orientation() == Vertical)
y += SkFloatToScalar(font->fontMetrics().floatAscent(IdeographicBaseline) - font->fontMetrics().floatAscent());
if (EmojiFont::IsAvailable()) {
// set filtering, to make scaled images look nice(r)
paint.setFilterBitmap(true);
int localIndex = 0;
int localCount = 0;
for (int i = 0; i < numGlyphs; i++) {
if (EmojiFont::IsEmojiGlyph(glyphs[i])) {
if (localCount)
canvas->drawPosText(&glyphs[localIndex],
localCount * sizeof(uint16_t),
&pos[localIndex], paint);
EmojiFont::Draw(canvas, glyphs[i], x, y, paint);
// reset local index/count track for "real" glyphs
localCount = 0;
localIndex = i + 1;
} else {
pos[i].set(x, y);
localCount += 1;
}
x += SkFloatToScalar(adv[i].width());
y += SkFloatToScalar(adv[i].height());
}
// draw the last run of glyphs (if any)
if (localCount)
canvas->drawPosText(&glyphs[localIndex],
localCount * sizeof(uint16_t),
&pos[localIndex], paint);
} else {
for (int i = 0; i < numGlyphs; i++) {
pos[i].set(x, y);
y += SkFloatToScalar(adv[i].height());
x += SkFloatToScalar(adv[i].width());
}
if (font->platformData().orientation() == Vertical) {
canvas->save();
canvas->rotate(-90);
SkMatrix rotator;
rotator.reset();
rotator.setRotate(90);
rotator.mapPoints(pos, numGlyphs);
}
canvas->drawPosText(glyphs, numGlyphs * sizeof(uint16_t), pos, paint);
if (font->platformData().orientation() == Vertical)
canvas->restore();
}
}
void Font::drawEmphasisMarksForComplexText(WebCore::GraphicsContext*, WebCore::TextRun const&, WTF::AtomicString const&, WebCore::FloatPoint const&, int, int) const
{
notImplemented();
}
#ifndef SUPPORT_COMPLEX_SCRIPTS
FloatRect Font::selectionRectForComplexText(const TextRun& run,
const FloatPoint& point, int h, int, int) const
{
SkPaint paint;
SkScalar width, left;
SkPaint::FontMetrics metrics;
primaryFont()->platformData().setupPaint(&paint);
width = paint.measureText(run.characters(), run.length() << 1);
SkScalar spacing = paint.getFontMetrics(&metrics);
return FloatRect(point.x(),
point.y(),
roundf(SkScalarToFloat(width)),
roundf(SkScalarToFloat(spacing)));
}
void Font::drawComplexText(GraphicsContext* gc, TextRun const& run,
FloatPoint const& point, int, int) const
{
SkCanvas* canvas = gc->platformContext()->mCanvas;
SkPaint paint;
if (!setupForText(&paint, gc, primaryFont())) {
return;
}
// go to chars, instead of glyphs, which was set by setupForText()
paint.setTextEncoding(SkPaint::kUTF16_TextEncoding);
canvas->drawText(run.characters(), run.length() << 1,
SkFloatToScalar(point.x()), SkFloatToScalar(point.y()),
paint);
}
float Font::floatWidthForComplexText(const TextRun& run, HashSet<const SimpleFontData*>*, GlyphOverflow*) const
{
SkPaint paint;
primaryFont()->platformData().setupPaint(&paint);
//printf("--------- complext measure %d chars\n", run.to() - run.from());
SkScalar width = paint.measureText(run.characters(), run.length() << 1);
return SkScalarToFloat(width);
}
int Font::offsetForPositionForComplexText(const TextRun& run, float x,
bool includePartialGlyphs) const
{
SkPaint paint;
int count = run.length();
SkAutoSTMalloc<64, SkScalar> storage(count);
SkScalar* widths = storage.get();
primaryFont()->platformData().setupPaint(&paint);
count = paint.getTextWidths(run.characters(), count << 1, widths);
if (count > 0)
{
SkScalar pos = 0;
for (int i = 0; i < count; i++)
{
if (x < SkScalarRound(pos + SkScalarHalf(widths[i])))
return i;
pos += widths[i];
}
}
return count;
}
#else
// TODO Should we remove the multilayer support?
// If yes. remove isCanvasMultiLayered() and adjustTextRenderMode().
static bool isCanvasMultiLayered(SkCanvas* canvas)
{
SkCanvas::LayerIter layerIterator(canvas, false);
layerIterator.next();
return !layerIterator.done();
}
static void adjustTextRenderMode(SkPaint* paint, bool isCanvasMultiLayered)
{
// Our layers only have a single alpha channel. This means that subpixel
// rendered text cannot be compositied correctly when the layer is
// collapsed. Therefore, subpixel text is disabled when we are drawing
// onto a layer.
if (isCanvasMultiLayered)
paint->setLCDRenderText(false);
}
// Harfbuzz uses 26.6 fixed point values for pixel offsets. However, we don't
// handle subpixel positioning so this function is used to truncate Harfbuzz
// values to a number of pixels.
static int truncateFixedPointToInteger(HB_Fixed value)
{
return value >> 6;
}
// TextRunWalker walks a TextRun and presents each script run in sequence. A
// TextRun is a sequence of code-points with the same embedding level (i.e. they
// are all left-to-right or right-to-left). A script run is a subsequence where
// all the characters have the same script (e.g. Arabic, Thai etc). Shaping is
// only ever done with script runs since the shapers only know how to deal with
// a single script.
//
// After creating it, the script runs are either iterated backwards or forwards.
// It defaults to backwards for RTL and forwards otherwise (which matches the
// presentation order), however you can set it with |setBackwardsIteration|.
//
// Once you have setup the object, call |nextScriptRun| to get the first script
// run. This will return false when the iteration is complete. At any time you
// can call |reset| to start over again.
class TextRunWalker {
public:
TextRunWalker(const TextRun&, int, int, const Font*);
~TextRunWalker();
bool isWordBreak(unsigned, bool);
// setPadding sets a number of pixels to be distributed across the TextRun.
// WebKit uses this to justify text.
void setPadding(int);
void reset();
void setBackwardsIteration(bool);
// Advance to the next script run, returning false when the end of the
// TextRun has been reached.
bool nextScriptRun();
float widthOfFullRun();
// setWordSpacingAdjustment sets a delta (in pixels) which is applied at
// each word break in the TextRun.
void setWordSpacingAdjustment(int wordSpacingAdjustment)
{
m_wordSpacingAdjustment = wordSpacingAdjustment;
}
// setLetterSpacingAdjustment sets an additional number of pixels that is
// added to the advance after each output cluster. This matches the behaviour
// of WidthIterator::advance.
//
// (NOTE: currently does nothing because I don't know how to get the
// cluster information from Harfbuzz.)
void setLetterSpacingAdjustment(int letterSpacingAdjustment)
{
m_letterSpacing = letterSpacingAdjustment;
}
// setWordAndLetterSpacing calls setWordSpacingAdjustment() and
// setLetterSpacingAdjustment() to override m_wordSpacingAdjustment
// and m_letterSpacing.
void setWordAndLetterSpacing(int wordSpacingAdjustment, int letterSpacingAdjustment);
// Set the x offset for the next script run. This affects the values in
// |xPositions|
void setXOffsetToZero() { m_offsetX = 0; }
bool rtl() const { return m_run.rtl(); }
const uint16_t* glyphs() const { return m_glyphs16; }
// Return the length of the array returned by |glyphs|
unsigned length() const { return m_item.num_glyphs; }
// Return the offset for each of the glyphs. Note that this is translated
// by the current x offset and that the x offset is updated for each script
// run.
const SkPoint* positions() const { return m_positions; }
// Get the advances (widths) for each glyph.
const HB_Fixed* advances() const { return m_item.advances; }
// Return the width (in px) of the current script run.
unsigned width() const { return m_pixelWidth; }
// Return the cluster log for the current script run. For example:
// script run: f i a n c é (fi gets ligatured)
// log clutrs: 0 0 1 2 3 4
// So, for each input code point, the log tells you which output glyph was
// generated for it.
const unsigned short* logClusters() const { return m_item.log_clusters; }
// return the number of code points in the current script run
unsigned numCodePoints() const { return m_numCodePoints; }
const FontPlatformData* fontPlatformDataForScriptRun() {
return reinterpret_cast<FontPlatformData*>(m_item.font->userData);
}
private:
enum CustomScript {
Bengali,
Devanagari,
Hebrew,
HebrewBold,
Naskh,
Tamil,
Thai,
NUM_SCRIPTS
};
static const char* paths[NUM_SCRIPTS];
void setupFontForScriptRun();
const FontPlatformData* setupComplexFont(CustomScript script,
const FontPlatformData& platformData);
HB_FontRec* allocHarfbuzzFont();
void deleteGlyphArrays();
void createGlyphArrays(int);
void resetGlyphArrays();
void shapeGlyphs();
void setGlyphPositions(bool);
static void normalizeSpacesAndMirrorChars(const UChar* source, bool rtl,
UChar* destination, int length);
static const TextRun& getNormalizedTextRun(const TextRun& originalRun,
OwnPtr<TextRun>& normalizedRun, OwnArrayPtr<UChar>& normalizedBuffer);
// This matches the logic in RenderBlock::findNextLineBreak
static bool isCodepointSpace(HB_UChar16 c) { return c == ' ' || c == '\t'; }
const Font* const m_font;
HB_ShaperItem m_item;
uint16_t* m_glyphs16; // A vector of 16-bit glyph ids.
SkPoint* m_positions; // A vector of positions for each glyph.
ssize_t m_indexOfNextScriptRun; // Indexes the script run in |m_run|.
const int m_startingX; // Offset in pixels of the first script run.
const int m_startingY; // Offset in pixels of the first script run.
int m_offsetX; // Offset in pixels to the start of the next script run.
unsigned m_pixelWidth; // Width (in px) of the current script run.
unsigned m_numCodePoints; // Code points in current script run.
unsigned m_glyphsArrayCapacity; // Current size of all the Harfbuzz arrays.
OwnPtr<TextRun> m_normalizedRun;
OwnArrayPtr<UChar> m_normalizedBuffer; // A buffer for normalized run.
const TextRun& m_run;
bool m_iterateBackwards;
int m_wordSpacingAdjustment; // delta adjustment (pixels) for each word break.
float m_padding; // pixels to be distributed over the line at word breaks.
float m_padPerWordBreak; // pixels to be added to each word break.
float m_padError; // |m_padPerWordBreak| might have a fractional component.
// Since we only add a whole number of padding pixels at
// each word break we accumulate error. This is the
// number of pixels that we are behind so far.
unsigned m_letterSpacing; // pixels to be added after each glyph.
};
// Indexed using enum CustomScript
const char* TextRunWalker::paths[] = {
"/system/fonts/Lohit-Bengali.ttf",
"/system/fonts/Lohit-Devanagari.ttf",
"/system/fonts/DroidSansHebrew-Regular.ttf",
"/system/fonts/DroidSansHebrew-Bold.ttf",
"/system/fonts/DroidNaskh-Regular.ttf",
"/system/fonts/Lohit-Tamil.ttf",
"/system/fonts/DroidSansThai.ttf"
};
TextRunWalker::TextRunWalker(const TextRun& run, int startingX, int startingY, const Font* font)
: m_font(font)
, m_startingX(startingX)
, m_startingY(startingY)
, m_offsetX(m_startingX)
, m_run(getNormalizedTextRun(run, m_normalizedRun, m_normalizedBuffer))
, m_iterateBackwards(m_run.rtl())
, m_wordSpacingAdjustment(0)
, m_padding(0)
, m_padPerWordBreak(0)
, m_padError(0)
, m_letterSpacing(0)
{
// Do not use |run| inside this constructor. Use |m_run| instead.
memset(&m_item, 0, sizeof(m_item));
// We cannot know, ahead of time, how many glyphs a given script run
// will produce. We take a guess that script runs will not produce more
// than twice as many glyphs as there are code points plus a bit of
// padding and fallback if we find that we are wrong.
createGlyphArrays((m_run.length() + 2) * 2);
m_item.log_clusters = new unsigned short[m_run.length()];
m_item.face = 0;
m_item.font = allocHarfbuzzFont();
m_item.item.bidiLevel = m_run.rtl();
m_item.string = m_run.characters();
m_item.stringLength = m_run.length();
reset();
}
TextRunWalker::~TextRunWalker()
{
fastFree(m_item.font);
deleteGlyphArrays();
delete[] m_item.log_clusters;
}
bool TextRunWalker::isWordBreak(unsigned index, bool isRTL)
{
if (!isRTL)
return index && isCodepointSpace(m_item.string[index])
&& !isCodepointSpace(m_item.string[index - 1]);
return index != m_item.stringLength - 1 && isCodepointSpace(m_item.string[index])
&& !isCodepointSpace(m_item.string[index + 1]);
}
// setPadding sets a number of pixels to be distributed across the TextRun.
// WebKit uses this to justify text.
void TextRunWalker::setPadding(int padding)
{
m_padding = padding;
if (!m_padding)
return;
// If we have padding to distribute, then we try to give an equal
// amount to each space. The last space gets the smaller amount, if
// any.
unsigned numWordBreaks = 0;
bool isRTL = m_iterateBackwards;
for (unsigned i = 0; i < m_item.stringLength; i++) {
if (isWordBreak(i, isRTL))
numWordBreaks++;
}
if (numWordBreaks)
m_padPerWordBreak = m_padding / numWordBreaks;
else
m_padPerWordBreak = 0;
}
void TextRunWalker::reset()
{
if (m_iterateBackwards)
m_indexOfNextScriptRun = m_run.length() - 1;
else
m_indexOfNextScriptRun = 0;
m_offsetX = m_startingX;
}
void TextRunWalker::setBackwardsIteration(bool isBackwards)
{
m_iterateBackwards = isBackwards;
reset();
}
// Advance to the next script run, returning false when the end of the
// TextRun has been reached.
bool TextRunWalker::nextScriptRun()
{
if (m_iterateBackwards) {
// In right-to-left mode we need to render the shaped glyph backwards and
// also render the script runs themselves backwards. So given a TextRun:
// AAAAAAACTTTTTTT (A = Arabic, C = Common, T = Thai)
// we render:
// TTTTTTCAAAAAAA
// (and the glyphs in each A, C and T section are backwards too)
if (!hb_utf16_script_run_prev(&m_numCodePoints, &m_item.item, m_run.characters(),
m_run.length(), &m_indexOfNextScriptRun))
return false;
} else {
if (!hb_utf16_script_run_next(&m_numCodePoints, &m_item.item, m_run.characters(),
m_run.length(), &m_indexOfNextScriptRun))
return false;
// It is actually wrong to consider script runs at all in this code.
// Other WebKit code (e.g. Mac) segments complex text just by finding
// the longest span of text covered by a single font.
// But we currently need to call hb_utf16_script_run_next anyway to fill
// in the harfbuzz data structures to e.g. pick the correct script's shaper.
// So we allow that to run first, then do a second pass over the range it
// found and take the largest subregion that stays within a single font.
const FontData* glyphData = m_font->glyphDataForCharacter(
m_item.string[m_item.item.pos], false).fontData;
unsigned endOfRun;
for (endOfRun = 1; endOfRun < m_item.item.length; ++endOfRun) {
const FontData* nextGlyphData = m_font->glyphDataForCharacter(
m_item.string[m_item.item.pos + endOfRun], false).fontData;
if (nextGlyphData != glyphData)
break;
}
m_item.item.length = endOfRun;
m_indexOfNextScriptRun = m_item.item.pos + endOfRun;
}
setupFontForScriptRun();
shapeGlyphs();
setGlyphPositions(rtl());
return true;
}
float TextRunWalker::widthOfFullRun()
{
float widthSum = 0;
while (nextScriptRun())
widthSum += width();
return widthSum;
}
void TextRunWalker::setWordAndLetterSpacing(int wordSpacingAdjustment,
int letterSpacingAdjustment)
{
setWordSpacingAdjustment(wordSpacingAdjustment);
setLetterSpacingAdjustment(letterSpacingAdjustment);
}
const FontPlatformData* TextRunWalker::setupComplexFont(
CustomScript script,
const FontPlatformData& platformData)
{
static FallbackHash fallbackPlatformData;
FallbackFontKey key(script, platformData.size());
FontPlatformData* newPlatformData = 0;
if (!fallbackPlatformData.contains(key)) {
SkTypeface* typeface = SkTypeface::CreateFromFile(paths[script]);
newPlatformData = new FontPlatformData(platformData, typeface);
SkSafeUnref(typeface);
fallbackPlatformData.set(key, newPlatformData);
}
if (!newPlatformData)
newPlatformData = fallbackPlatformData.get(key);
// If we couldn't allocate a new FontPlatformData, revert to the one passed
return newPlatformData ? newPlatformData : &platformData;
}
void TextRunWalker::setupFontForScriptRun()
{
const FontData* fontData = m_font->glyphDataForCharacter(m_run[0], false).fontData;
const FontPlatformData& platformData =
fontData->fontDataForCharacter(' ')->platformData();
const FontPlatformData* complexPlatformData = &platformData;
switch (m_item.item.script) {
case HB_Script_Bengali:
complexPlatformData = setupComplexFont(Bengali, platformData);
break;
case HB_Script_Devanagari:
complexPlatformData = setupComplexFont(Devanagari, platformData);
break;
case HB_Script_Hebrew:
switch (platformData.typeface()->style()) {
case SkTypeface::kBold:
case SkTypeface::kBoldItalic:
complexPlatformData = setupComplexFont(HebrewBold, platformData);
break;
case SkTypeface::kNormal:
case SkTypeface::kItalic:
default:
complexPlatformData = setupComplexFont(Hebrew, platformData);
break;
}
break;
case HB_Script_Arabic:
complexPlatformData = setupComplexFont(Naskh, platformData);
break;
case HB_Script_Tamil:
complexPlatformData = setupComplexFont(Tamil, platformData);
break;
case HB_Script_Thai:
complexPlatformData = setupComplexFont(Thai, platformData);
break;
default:
// HB_Script_Common; includes Ethiopic
complexPlatformData = &platformData;
break;
}
m_item.face = complexPlatformData->harfbuzzFace();
m_item.font->userData = const_cast<FontPlatformData*>(complexPlatformData);
int size = complexPlatformData->size();
m_item.font->x_ppem = size;
m_item.font->y_ppem = size;
// x_ and y_scale are the conversion factors from font design space (fEmSize) to 1/64th of device pixels in 16.16 format.
const int devicePixelFraction = 64;
const int multiplyFor16Dot16 = 1 << 16;
int scale = devicePixelFraction * size * multiplyFor16Dot16 / complexPlatformData->emSizeInFontUnits();
m_item.font->x_scale = scale;
m_item.font->y_scale = scale;
}
HB_FontRec* TextRunWalker::allocHarfbuzzFont()
{
HB_FontRec* font = reinterpret_cast<HB_FontRec*>(fastMalloc(sizeof(HB_FontRec)));
memset(font, 0, sizeof(HB_FontRec));
font->klass = &harfbuzzSkiaClass;
font->userData = 0;
return font;
}
void TextRunWalker::deleteGlyphArrays()
{
delete[] m_item.glyphs;
delete[] m_item.attributes;
delete[] m_item.advances;
delete[] m_item.offsets;
delete[] m_glyphs16;
delete[] m_positions;
}
void TextRunWalker::createGlyphArrays(int size)
{
m_item.glyphs = new HB_Glyph[size];
m_item.attributes = new HB_GlyphAttributes[size];
m_item.advances = new HB_Fixed[size];
m_item.offsets = new HB_FixedPoint[size];
m_glyphs16 = new uint16_t[size];
m_positions = new SkPoint[size];
m_item.num_glyphs = size;
m_glyphsArrayCapacity = size; // Save the GlyphArrays size.
}
void TextRunWalker::resetGlyphArrays()
{
int size = m_item.num_glyphs;
// All the types here don't have pointers. It is safe to reset to
// zero unless Harfbuzz breaks the compatibility in the future.
memset(m_item.glyphs, 0, size * sizeof(m_item.glyphs[0]));
memset(m_item.attributes, 0, size * sizeof(m_item.attributes[0]));
memset(m_item.advances, 0, size * sizeof(m_item.advances[0]));
memset(m_item.offsets, 0, size * sizeof(m_item.offsets[0]));
memset(m_glyphs16, 0, size * sizeof(m_glyphs16[0]));
memset(m_positions, 0, size * sizeof(m_positions[0]));
}
void TextRunWalker::shapeGlyphs()
{
// HB_ShapeItem() resets m_item.num_glyphs. If the previous call to
// HB_ShapeItem() used less space than was available, the capacity of
// the array may be larger than the current value of m_item.num_glyphs.
// So, we need to reset the num_glyphs to the capacity of the array.
m_item.num_glyphs = m_glyphsArrayCapacity;
resetGlyphArrays();
while (!HB_ShapeItem(&m_item)) {
// We overflowed our arrays. Resize and retry.
// HB_ShapeItem fills in m_item.num_glyphs with the needed size.
deleteGlyphArrays();
createGlyphArrays(m_item.num_glyphs << 1);
resetGlyphArrays();
}
}
void TextRunWalker::setGlyphPositions(bool isRTL)
{
int position = 0;
// logClustersIndex indexes logClusters for the first (or last when
// RTL) codepoint of the current glyph. Each time we advance a glyph,
// we skip over all the codepoints that contributed to the current
// glyph.
unsigned logClustersIndex = isRTL && m_item.num_glyphs ? m_item.num_glyphs - 1 : 0;
for (unsigned iter = 0; iter < m_item.num_glyphs; ++iter) {
// Glyphs are stored in logical order, but for layout purposes we
// always go left to right.
int i = isRTL ? m_item.num_glyphs - iter - 1 : iter;
m_glyphs16[i] = m_item.glyphs[i];
int offsetX = truncateFixedPointToInteger(m_item.offsets[i].x);
int offsetY = truncateFixedPointToInteger(m_item.offsets[i].y);
m_positions[i].set(SkIntToScalar(m_offsetX + position) + offsetX, m_startingY + offsetY);
int advance = truncateFixedPointToInteger(m_item.advances[i]);
// The first half of the conjunction works around the case where
// output glyphs aren't associated with any codepoints by the
// clusters log.
if (logClustersIndex < m_item.item.length
&& isWordBreak(m_item.item.pos + logClustersIndex, isRTL)) {
advance += m_wordSpacingAdjustment;
if (m_padding > 0) {
int toPad = roundf(m_padPerWordBreak + m_padError);
m_padError += m_padPerWordBreak - toPad;
if (m_padding < toPad)
toPad = m_padding;
m_padding -= toPad;
advance += toPad;
}
}
// ZeroWidthJoiners and ZeroWidthNonJoiners should be stripped by
// Harfbuzz, but aren't. Check for zwj and zwnj and replace with a
// zero width space. We get the glyph data for space instead of
// zeroWidthSpace because the latter was seen to render with an
// unexpected code point (the symbol for a cloud). Since the standard
// space is in page zero and since we've also confirmed that there is
// no advance on this glyph, that should be ok.
if (0 == m_item.advances[i]) {
const HB_UChar16 c = m_item.string[m_item.item.pos + logClustersIndex];
if ((c == zeroWidthJoiner) || (c == zeroWidthNonJoiner)) {
static Glyph spaceGlyph = m_font->glyphDataForCharacter(space, false).glyph;
m_glyphs16[i] = spaceGlyph;
}
}
// TODO We would like to add m_letterSpacing after each cluster, but I
// don't know where the cluster information is. This is typically
// fine for Roman languages, but breaks more complex languages
// terribly.
// advance += m_letterSpacing;
if (isRTL) {
while (logClustersIndex > 0 && logClusters()[logClustersIndex] == i)
logClustersIndex--;
} else {
while (logClustersIndex < m_item.item.length
&& logClusters()[logClustersIndex] == i)
logClustersIndex++;
}
position += advance;
}
m_pixelWidth = position;
m_offsetX += m_pixelWidth;
}
void TextRunWalker::normalizeSpacesAndMirrorChars(const UChar* source, bool rtl,
UChar* destination, int length)
{
int position = 0;
bool error = false;
// Iterate characters in source and mirror character if needed.
while (position < length) {
UChar32 character;
int nextPosition = position;
U16_NEXT(source, nextPosition, length, character);
if (Font::treatAsSpace(character))
character = space;
else if (Font::treatAsZeroWidthSpaceInComplexScript(character))
character = zeroWidthSpace;
else if (rtl)
character = u_charMirror(character);
U16_APPEND(destination, position, length, character, error);
ASSERT(!error);
position = nextPosition;
}
}
const TextRun& TextRunWalker::getNormalizedTextRun(const TextRun& originalRun,
OwnPtr<TextRun>& normalizedRun, OwnArrayPtr<UChar>& normalizedBuffer)
{
// Normalize the text run in three ways:
// 1) Convert the |originalRun| to NFC normalized form if combining diacritical marks
// (U+0300..) are used in the run. This conversion is necessary since most OpenType
// fonts (e.g., Arial) don't have substitution rules for the diacritical marks in
// their GSUB tables.
//
// Note that we don't use the icu::Normalizer::isNormalized(UNORM_NFC) API here since
// the API returns FALSE (= not normalized) for complex runs that don't require NFC
// normalization (e.g., Arabic text). Unless the run contains the diacritical marks,
// Harfbuzz will do the same thing for us using the GSUB table.
// 2) Convert spacing characters into plain spaces, as some fonts will provide glyphs
// for characters like '\n' otherwise.
// 3) Convert mirrored characters such as parenthesis for rtl text.
// Convert to NFC form if the text has diacritical marks.
icu::UnicodeString normalizedString;
UErrorCode error = U_ZERO_ERROR;
for (int16_t i = 0; i < originalRun.length(); ++i) {
UChar ch = originalRun[i];
if (::ublock_getCode(ch) == UBLOCK_COMBINING_DIACRITICAL_MARKS) {
icu::Normalizer::normalize(icu::UnicodeString(originalRun.characters(),
originalRun.length()), UNORM_NFC, 0 /* no options */,
normalizedString, error);
if (U_FAILURE(error))
return originalRun;
break;
}
}
// Normalize space and mirror parenthesis for rtl text.
int normalizedBufferLength;
const UChar* sourceText;
if (normalizedString.isEmpty()) {
normalizedBufferLength = originalRun.length();
sourceText = originalRun.characters();
} else {
normalizedBufferLength = normalizedString.length();
sourceText = normalizedString.getBuffer();
}
normalizedBuffer = adoptArrayPtr(new UChar[normalizedBufferLength + 1]);
normalizeSpacesAndMirrorChars(sourceText, originalRun.rtl(), normalizedBuffer.get(),
normalizedBufferLength);
normalizedRun = adoptPtr(new TextRun(originalRun));
normalizedRun->setText(normalizedBuffer.get(), normalizedBufferLength);
return *normalizedRun;
}
FloatRect Font::selectionRectForComplexText(const TextRun& run,
const FloatPoint& point, int height, int from, int to) const
{
int fromX = -1, toX = -1, fromAdvance = -1, toAdvance = -1;
TextRunWalker walker(run, 0, 0, this);
walker.setWordAndLetterSpacing(wordSpacing(), letterSpacing());
// Base will point to the x offset for the current script run. Note that, in
// the LTR case, width will be 0.
int base = walker.rtl() ? walker.widthOfFullRun() : 0;
const int leftEdge = base;
// We want to enumerate the script runs in code point order in the following
// code. This call also resets |walker|.
walker.setBackwardsIteration(false);
while (walker.nextScriptRun() && (fromX == -1 || toX == -1)) {
// TextRunWalker will helpfully accumulate the x offsets for different
// script runs for us. For this code, however, we always want the x
// offsets to start from zero so we call this before each script run.
walker.setXOffsetToZero();
if (walker.rtl())
base -= walker.width();
int numCodePoints = static_cast<int>(walker.numCodePoints());
if (fromX == -1 && from < numCodePoints) {
// |from| is within this script run. So we index the clusters log to
// find which glyph this code-point contributed to and find its x
// position.
int glyph = walker.logClusters()[from];
fromX = base + walker.positions()[glyph].x();
fromAdvance = walker.advances()[glyph];
} else if (!walker.rtl())
from -= numCodePoints;
if (toX == -1 && to < numCodePoints) {
int glyph = walker.logClusters()[to];
toX = base + walker.positions()[glyph].x();
toAdvance = walker.advances()[glyph];
} else if (!walker.rtl())
to -= numCodePoints;
if (!walker.rtl())
base += walker.width();
}
// The position in question might be just after the text.
const int rightEdge = base;
if (fromX == -1 && !from)
fromX = leftEdge;
else if (walker.rtl())
fromX += truncateFixedPointToInteger(fromAdvance);
if (toX == -1 && !to)
toX = rightEdge;
ASSERT(fromX != -1 && toX != -1);
if (fromX < toX)
return FloatRect(point.x() + fromX, point.y(), toX - fromX, height);
return FloatRect(point.x() + toX, point.y(), fromX - toX, height);
}
void Font::drawComplexText(GraphicsContext* gc, TextRun const& run,
FloatPoint const& point, int, int) const
{
if (!run.length())
return;
int mode = gc->textDrawingMode();
bool fill = mode & TextModeFill;
bool stroke = mode & TextModeStroke;
if (!fill && !stroke)
return;
SkPaint fillPaint, strokePaint;
if (fill)
setupFill(&fillPaint, gc, primaryFont());
if (stroke)
setupStroke(&strokePaint, gc, primaryFont());
SkCanvas* canvas = gc->platformContext()->mCanvas;
bool haveMultipleLayers = isCanvasMultiLayered(canvas);
TextRunWalker walker(run, point.x(), point.y(), this);
walker.setWordAndLetterSpacing(wordSpacing(), letterSpacing());
walker.setPadding(run.expansion());
while (walker.nextScriptRun()) {
if (fill) {
walker.fontPlatformDataForScriptRun()->setupPaint(&fillPaint);
adjustTextRenderMode(&fillPaint, haveMultipleLayers);
canvas->drawPosText(walker.glyphs(), walker.length() << 1,
walker.positions(), fillPaint);
}
if (stroke) {
walker.fontPlatformDataForScriptRun()->setupPaint(&strokePaint);
adjustTextRenderMode(&strokePaint, haveMultipleLayers);
canvas->drawPosText(walker.glyphs(), walker.length() << 1,
walker.positions(), strokePaint);
}
}
}
float Font::floatWidthForComplexText(const TextRun& run,
HashSet<const SimpleFontData*>*, GlyphOverflow*) const
{
TextRunWalker walker(run, 0, 0, this);
walker.setWordAndLetterSpacing(wordSpacing(), letterSpacing());
return walker.widthOfFullRun();
}
static int glyphIndexForXPositionInScriptRun(const TextRunWalker& walker, int x)
{
const HB_Fixed* advances = walker.advances();
int glyphIndex;
if (walker.rtl()) {
for (glyphIndex = walker.length() - 1; glyphIndex >= 0; --glyphIndex) {
if (x < truncateFixedPointToInteger(advances[glyphIndex]))
break;
x -= truncateFixedPointToInteger(advances[glyphIndex]);
}
} else {
for (glyphIndex = 0; glyphIndex < static_cast<int>(walker.length());
++glyphIndex) {
if (x < truncateFixedPointToInteger(advances[glyphIndex]))
break;
x -= truncateFixedPointToInteger(advances[glyphIndex]);
}
}
return glyphIndex;
}
int Font::offsetForPositionForComplexText(const TextRun& run, float x,
bool includePartialGlyphs) const
{
// (Mac code ignores includePartialGlyphs, and they don't know what it's
// supposed to do, so we just ignore it as well.)
TextRunWalker walker(run, 0, 0, this);
walker.setWordAndLetterSpacing(wordSpacing(), letterSpacing());
// If this is RTL text, the first glyph from the left is actually the last
// code point. So we need to know how many code points there are total in
// order to subtract. This is different from the length of the TextRun
// because UTF-16 surrogate pairs are a single code point, but 32-bits long.
// In LTR we leave this as 0 so that we get the correct value for
// |basePosition|, below.
unsigned totalCodePoints = 0;
if (walker.rtl()) {
ssize_t offset = 0;
while (offset < run.length()) {
utf16_to_code_point(run.characters(), run.length(), &offset);
totalCodePoints++;
}
}
unsigned basePosition = totalCodePoints;
// For RTL:
// code-point order: abcd efg hijkl
// on screen: lkjih gfe dcba
// ^ ^
// | |
// basePosition--| |
// totalCodePoints----|
// Since basePosition is currently the total number of code-points, the
// first thing we do is decrement it so that it's pointing to the start of
// the current script-run.
//
// For LTR, basePosition is zero so it already points to the start of the
// first script run.
while (walker.nextScriptRun()) {
if (walker.rtl())
basePosition -= walker.numCodePoints();
if (x >= 0 && x < static_cast<int>(walker.width())) {
// The x value in question is within this script run. We consider
// each glyph in presentation order and stop when we find the one
// covering this position.
const int glyphIndex = glyphIndexForXPositionInScriptRun(walker, x);
// Now that we have a glyph index, we have to turn that into a
// code-point index. Because of ligatures, several code-points may
// have gone into a single glyph. We iterate over the clusters log
// and find the first code-point which contributed to the glyph.
// Some shapers (i.e. Khmer) will produce cluster logs which report
// that /no/ code points contributed to certain glyphs. Because of
// this, we take any code point which contributed to the glyph in
// question, or any subsequent glyph. If we run off the end, then
// we take the last code point.
const unsigned short* log = walker.logClusters();
for (unsigned j = 0; j < walker.numCodePoints(); ++j) {
if (log[j] >= glyphIndex)
return basePosition + j;
}
return basePosition + walker.numCodePoints() - 1;
}
x -= walker.width();
if (!walker.rtl())
basePosition += walker.numCodePoints();
}
return basePosition;
}
#endif
}
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