// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/gfx/render_text_harfbuzz.h"
#include <limits>
#include <map>
#include "base/i18n/bidi_line_iterator.h"
#include "base/i18n/break_iterator.h"
#include "base/i18n/char_iterator.h"
#include "base/lazy_instance.h"
#include "third_party/harfbuzz-ng/src/hb.h"
#include "third_party/icu/source/common/unicode/ubidi.h"
#include "third_party/skia/include/core/SkColor.h"
#include "third_party/skia/include/core/SkTypeface.h"
#include "ui/gfx/canvas.h"
#include "ui/gfx/font_fallback.h"
#include "ui/gfx/font_render_params.h"
#include "ui/gfx/utf16_indexing.h"
#if defined(OS_WIN)
#include "ui/gfx/font_fallback_win.h"
#endif
namespace gfx {
namespace {
// Text length limit. Longer strings are slow and not fully tested.
const size_t kMaxTextLength = 10000;
// The maximum number of scripts a Unicode character can belong to. This value
// is arbitrarily chosen to be a good limit because it is unlikely for a single
// character to belong to more scripts.
const size_t kMaxScripts = 5;
// Maps from code points to glyph indices in a font.
typedef std::map<uint32_t, uint16_t> GlyphCache;
// Font data provider for HarfBuzz using Skia. Copied from Blink.
// TODO(ckocagil): Eliminate the duplication. http://crbug.com/368375
struct FontData {
FontData(GlyphCache* glyph_cache) : glyph_cache_(glyph_cache) {}
SkPaint paint_;
GlyphCache* glyph_cache_;
};
hb_position_t SkiaScalarToHarfBuzzPosition(SkScalar value) {
return SkScalarToFixed(value);
}
// Deletes the object at the given pointer after casting it to the given type.
template<typename Type>
void DeleteByType(void* data) {
Type* typed_data = reinterpret_cast<Type*>(data);
delete typed_data;
}
template<typename Type>
void DeleteArrayByType(void* data) {
Type* typed_data = reinterpret_cast<Type*>(data);
delete[] typed_data;
}
// Outputs the |width| and |extents| of the glyph with index |codepoint| in
// |paint|'s font.
void GetGlyphWidthAndExtents(SkPaint* paint,
hb_codepoint_t codepoint,
hb_position_t* width,
hb_glyph_extents_t* extents) {
DCHECK_LE(codepoint, 0xFFFFU);
paint->setTextEncoding(SkPaint::kGlyphID_TextEncoding);
SkScalar sk_width;
SkRect sk_bounds;
uint16_t glyph = codepoint;
paint->getTextWidths(&glyph, sizeof(glyph), &sk_width, &sk_bounds);
if (width)
*width = SkiaScalarToHarfBuzzPosition(sk_width);
if (extents) {
// Invert y-axis because Skia is y-grows-down but we set up HarfBuzz to be
// y-grows-up.
extents->x_bearing = SkiaScalarToHarfBuzzPosition(sk_bounds.fLeft);
extents->y_bearing = SkiaScalarToHarfBuzzPosition(-sk_bounds.fTop);
extents->width = SkiaScalarToHarfBuzzPosition(sk_bounds.width());
extents->height = SkiaScalarToHarfBuzzPosition(-sk_bounds.height());
}
}
// Writes the |glyph| index for the given |unicode| code point. Returns whether
// the glyph exists, i.e. it is not a missing glyph.
hb_bool_t GetGlyph(hb_font_t* font,
void* data,
hb_codepoint_t unicode,
hb_codepoint_t variation_selector,
hb_codepoint_t* glyph,
void* user_data) {
FontData* font_data = reinterpret_cast<FontData*>(data);
GlyphCache* cache = font_data->glyph_cache_;
bool exists = cache->count(unicode) != 0;
if (!exists) {
SkPaint* paint = &font_data->paint_;
paint->setTextEncoding(SkPaint::kUTF32_TextEncoding);
paint->textToGlyphs(&unicode, sizeof(hb_codepoint_t), &(*cache)[unicode]);
}
*glyph = (*cache)[unicode];
return !!*glyph;
}
// Returns the horizontal advance value of the |glyph|.
hb_position_t GetGlyphHorizontalAdvance(hb_font_t* font,
void* data,
hb_codepoint_t glyph,
void* user_data) {
FontData* font_data = reinterpret_cast<FontData*>(data);
hb_position_t advance = 0;
GetGlyphWidthAndExtents(&font_data->paint_, glyph, &advance, 0);
return advance;
}
hb_bool_t GetGlyphHorizontalOrigin(hb_font_t* font,
void* data,
hb_codepoint_t glyph,
hb_position_t* x,
hb_position_t* y,
void* user_data) {
// Just return true, like the HarfBuzz-FreeType implementation.
return true;
}
hb_position_t GetGlyphKerning(FontData* font_data,
hb_codepoint_t first_glyph,
hb_codepoint_t second_glyph) {
SkTypeface* typeface = font_data->paint_.getTypeface();
const uint16_t glyphs[2] = { static_cast<uint16_t>(first_glyph),
static_cast<uint16_t>(second_glyph) };
int32_t kerning_adjustments[1] = { 0 };
if (!typeface->getKerningPairAdjustments(glyphs, 2, kerning_adjustments))
return 0;
SkScalar upm = SkIntToScalar(typeface->getUnitsPerEm());
SkScalar size = font_data->paint_.getTextSize();
return SkiaScalarToHarfBuzzPosition(
SkScalarMulDiv(SkIntToScalar(kerning_adjustments[0]), size, upm));
}
hb_position_t GetGlyphHorizontalKerning(hb_font_t* font,
void* data,
hb_codepoint_t left_glyph,
hb_codepoint_t right_glyph,
void* user_data) {
FontData* font_data = reinterpret_cast<FontData*>(data);
if (font_data->paint_.isVerticalText()) {
// We don't support cross-stream kerning.
return 0;
}
return GetGlyphKerning(font_data, left_glyph, right_glyph);
}
hb_position_t GetGlyphVerticalKerning(hb_font_t* font,
void* data,
hb_codepoint_t top_glyph,
hb_codepoint_t bottom_glyph,
void* user_data) {
FontData* font_data = reinterpret_cast<FontData*>(data);
if (!font_data->paint_.isVerticalText()) {
// We don't support cross-stream kerning.
return 0;
}
return GetGlyphKerning(font_data, top_glyph, bottom_glyph);
}
// Writes the |extents| of |glyph|.
hb_bool_t GetGlyphExtents(hb_font_t* font,
void* data,
hb_codepoint_t glyph,
hb_glyph_extents_t* extents,
void* user_data) {
FontData* font_data = reinterpret_cast<FontData*>(data);
GetGlyphWidthAndExtents(&font_data->paint_, glyph, 0, extents);
return true;
}
class FontFuncs {
public:
FontFuncs() : font_funcs_(hb_font_funcs_create()) {
hb_font_funcs_set_glyph_func(font_funcs_, GetGlyph, 0, 0);
hb_font_funcs_set_glyph_h_advance_func(
font_funcs_, GetGlyphHorizontalAdvance, 0, 0);
hb_font_funcs_set_glyph_h_kerning_func(
font_funcs_, GetGlyphHorizontalKerning, 0, 0);
hb_font_funcs_set_glyph_h_origin_func(
font_funcs_, GetGlyphHorizontalOrigin, 0, 0);
hb_font_funcs_set_glyph_v_kerning_func(
font_funcs_, GetGlyphVerticalKerning, 0, 0);
hb_font_funcs_set_glyph_extents_func(
font_funcs_, GetGlyphExtents, 0, 0);
hb_font_funcs_make_immutable(font_funcs_);
}
~FontFuncs() {
hb_font_funcs_destroy(font_funcs_);
}
hb_font_funcs_t* get() { return font_funcs_; }
private:
hb_font_funcs_t* font_funcs_;
DISALLOW_COPY_AND_ASSIGN(FontFuncs);
};
base::LazyInstance<FontFuncs>::Leaky g_font_funcs = LAZY_INSTANCE_INITIALIZER;
// Returns the raw data of the font table |tag|.
hb_blob_t* GetFontTable(hb_face_t* face, hb_tag_t tag, void* user_data) {
SkTypeface* typeface = reinterpret_cast<SkTypeface*>(user_data);
const size_t table_size = typeface->getTableSize(tag);
if (!table_size)
return 0;
scoped_ptr<char[]> buffer(new char[table_size]);
if (!buffer)
return 0;
size_t actual_size = typeface->getTableData(tag, 0, table_size, buffer.get());
if (table_size != actual_size)
return 0;
char* buffer_raw = buffer.release();
return hb_blob_create(buffer_raw, table_size, HB_MEMORY_MODE_WRITABLE,
buffer_raw, DeleteArrayByType<char>);
}
void UnrefSkTypeface(void* data) {
SkTypeface* skia_face = reinterpret_cast<SkTypeface*>(data);
SkSafeUnref(skia_face);
}
// Wrapper class for a HarfBuzz face created from a given Skia face.
class HarfBuzzFace {
public:
HarfBuzzFace() : face_(NULL) {}
~HarfBuzzFace() {
if (face_)
hb_face_destroy(face_);
}
void Init(SkTypeface* skia_face) {
SkSafeRef(skia_face);
face_ = hb_face_create_for_tables(GetFontTable, skia_face, UnrefSkTypeface);
DCHECK(face_);
}
hb_face_t* get() {
return face_;
}
private:
hb_face_t* face_;
};
// Creates a HarfBuzz font from the given Skia face and text size.
hb_font_t* CreateHarfBuzzFont(SkTypeface* skia_face,
int text_size,
const FontRenderParams& params,
bool background_is_transparent) {
typedef std::pair<HarfBuzzFace, GlyphCache> FaceCache;
// TODO(ckocagil): This shouldn't grow indefinitely. Maybe use base::MRUCache?
static std::map<SkFontID, FaceCache> face_caches;
FaceCache* face_cache = &face_caches[skia_face->uniqueID()];
if (face_cache->first.get() == NULL)
face_cache->first.Init(skia_face);
hb_font_t* harfbuzz_font = hb_font_create(face_cache->first.get());
const int scale = SkScalarToFixed(text_size);
hb_font_set_scale(harfbuzz_font, scale, scale);
FontData* hb_font_data = new FontData(&face_cache->second);
hb_font_data->paint_.setTypeface(skia_face);
hb_font_data->paint_.setTextSize(text_size);
// TODO(ckocagil): Do we need to update these params later?
internal::ApplyRenderParams(params, background_is_transparent,
&hb_font_data->paint_);
hb_font_set_funcs(harfbuzz_font, g_font_funcs.Get().get(), hb_font_data,
DeleteByType<FontData>);
hb_font_make_immutable(harfbuzz_font);
return harfbuzz_font;
}
// Returns true if characters of |block_code| may trigger font fallback.
bool IsUnusualBlockCode(UBlockCode block_code) {
return block_code == UBLOCK_GEOMETRIC_SHAPES ||
block_code == UBLOCK_MISCELLANEOUS_SYMBOLS;
}
bool IsBracket(UChar32 character) {
static const char kBrackets[] = { '(', ')', '{', '}', '<', '>', };
static const char* kBracketsEnd = kBrackets + arraysize(kBrackets);
return std::find(kBrackets, kBracketsEnd, character) != kBracketsEnd;
}
// Returns the boundary between a special and a regular character. Special
// characters are brackets or characters that satisfy |IsUnusualBlockCode|.
size_t FindRunBreakingCharacter(const base::string16& text,
size_t run_start,
size_t run_break) {
const int32 run_length = static_cast<int32>(run_break - run_start);
base::i18n::UTF16CharIterator iter(text.c_str() + run_start, run_length);
const UChar32 first_char = iter.get();
const UBlockCode first_block = ublock_getCode(first_char);
const bool first_block_unusual = IsUnusualBlockCode(first_block);
const bool first_bracket = IsBracket(first_char);
while (iter.Advance() && iter.array_pos() < run_length) {
const UChar32 current_char = iter.get();
const UBlockCode current_block = ublock_getCode(current_char);
const bool block_break = current_block != first_block &&
(first_block_unusual || IsUnusualBlockCode(current_block));
if (block_break || first_bracket != IsBracket(current_char))
return run_start + iter.array_pos();
}
return run_break;
}
// If the given scripts match, returns the one that isn't USCRIPT_COMMON or
// USCRIPT_INHERITED, i.e. the more specific one. Otherwise returns
// USCRIPT_INVALID_CODE.
UScriptCode ScriptIntersect(UScriptCode first, UScriptCode second) {
if (first == second ||
(second > USCRIPT_INVALID_CODE && second <= USCRIPT_INHERITED)) {
return first;
}
if (first > USCRIPT_INVALID_CODE && first <= USCRIPT_INHERITED)
return second;
return USCRIPT_INVALID_CODE;
}
// Writes the script and the script extensions of the character with the
// Unicode |codepoint|. Returns the number of written scripts.
int GetScriptExtensions(UChar32 codepoint, UScriptCode* scripts) {
UErrorCode icu_error = U_ZERO_ERROR;
// ICU documentation incorrectly states that the result of
// |uscript_getScriptExtensions| will contain the regular script property.
// Write the character's script property to the first element.
scripts[0] = uscript_getScript(codepoint, &icu_error);
if (U_FAILURE(icu_error))
return 0;
// Fill the rest of |scripts| with the extensions.
int count = uscript_getScriptExtensions(codepoint, scripts + 1,
kMaxScripts - 1, &icu_error);
if (U_FAILURE(icu_error))
count = 0;
return count + 1;
}
// Intersects the script extensions set of |codepoint| with |result| and writes
// to |result|, reading and updating |result_size|.
void ScriptSetIntersect(UChar32 codepoint,
UScriptCode* result,
size_t* result_size) {
UScriptCode scripts[kMaxScripts] = { USCRIPT_INVALID_CODE };
int count = GetScriptExtensions(codepoint, scripts);
size_t out_size = 0;
for (size_t i = 0; i < *result_size; ++i) {
for (int j = 0; j < count; ++j) {
UScriptCode intersection = ScriptIntersect(result[i], scripts[j]);
if (intersection != USCRIPT_INVALID_CODE) {
result[out_size++] = intersection;
break;
}
}
}
*result_size = out_size;
}
// Find the longest sequence of characters from 0 and up to |length| that
// have at least one common UScriptCode value. Writes the common script value to
// |script| and returns the length of the sequence. Takes the characters' script
// extensions into account. http://www.unicode.org/reports/tr24/#ScriptX
//
// Consider 3 characters with the script values {Kana}, {Hira, Kana}, {Kana}.
// Without script extensions only the first script in each set would be taken
// into account, resulting in 3 runs where 1 would be enough.
// TODO(ckocagil): Write a unit test for the case above.
int ScriptInterval(const base::string16& text,
size_t start,
size_t length,
UScriptCode* script) {
DCHECK_GT(length, 0U);
UScriptCode scripts[kMaxScripts] = { USCRIPT_INVALID_CODE };
base::i18n::UTF16CharIterator char_iterator(text.c_str() + start, length);
size_t scripts_size = GetScriptExtensions(char_iterator.get(), scripts);
*script = scripts[0];
while (char_iterator.Advance()) {
ScriptSetIntersect(char_iterator.get(), scripts, &scripts_size);
if (scripts_size == 0U)
return char_iterator.array_pos();
*script = scripts[0];
}
return length;
}
// A port of hb_icu_script_to_script because harfbuzz on CrOS is built without
// hb-icu. See http://crbug.com/356929
inline hb_script_t ICUScriptToHBScript(UScriptCode script) {
if (script == USCRIPT_INVALID_CODE)
return HB_SCRIPT_INVALID;
return hb_script_from_string(uscript_getShortName(script), -1);
}
// Helper template function for |TextRunHarfBuzz::GetClusterAt()|. |Iterator|
// can be a forward or reverse iterator type depending on the text direction.
template <class Iterator>
void GetClusterAtImpl(size_t pos,
Range range,
Iterator elements_begin,
Iterator elements_end,
bool reversed,
Range* chars,
Range* glyphs) {
Iterator element = std::upper_bound(elements_begin, elements_end, pos);
chars->set_end(element == elements_end ? range.end() : *element);
glyphs->set_end(reversed ? elements_end - element : element - elements_begin);
DCHECK(element != elements_begin);
while (--element != elements_begin && *element == *(element - 1));
chars->set_start(*element);
glyphs->set_start(
reversed ? elements_end - element : element - elements_begin);
if (reversed)
*glyphs = Range(glyphs->end(), glyphs->start());
DCHECK(!chars->is_reversed());
DCHECK(!chars->is_empty());
DCHECK(!glyphs->is_reversed());
DCHECK(!glyphs->is_empty());
}
} // namespace
namespace internal {
TextRunHarfBuzz::TextRunHarfBuzz()
: width(0.0f),
preceding_run_widths(0.0f),
is_rtl(false),
level(0),
script(USCRIPT_INVALID_CODE),
glyph_count(static_cast<size_t>(-1)),
font_size(0),
font_style(0),
strike(false),
diagonal_strike(false),
underline(false) {}
TextRunHarfBuzz::~TextRunHarfBuzz() {}
void TextRunHarfBuzz::GetClusterAt(size_t pos,
Range* chars,
Range* glyphs) const {
DCHECK(range.Contains(Range(pos, pos + 1)));
DCHECK(chars);
DCHECK(glyphs);
if (glyph_count == 0) {
*chars = range;
*glyphs = Range();
return;
}
if (is_rtl) {
GetClusterAtImpl(pos, range, glyph_to_char.rbegin(), glyph_to_char.rend(),
true, chars, glyphs);
return;
}
GetClusterAtImpl(pos, range, glyph_to_char.begin(), glyph_to_char.end(),
false, chars, glyphs);
}
Range TextRunHarfBuzz::CharRangeToGlyphRange(const Range& char_range) const {
DCHECK(range.Contains(char_range));
DCHECK(!char_range.is_reversed());
DCHECK(!char_range.is_empty());
Range start_glyphs;
Range end_glyphs;
Range temp_range;
GetClusterAt(char_range.start(), &temp_range, &start_glyphs);
GetClusterAt(char_range.end() - 1, &temp_range, &end_glyphs);
return is_rtl ? Range(end_glyphs.start(), start_glyphs.end()) :
Range(start_glyphs.start(), end_glyphs.end());
}
size_t TextRunHarfBuzz::CountMissingGlyphs() const {
static const int kMissingGlyphId = 0;
size_t missing = 0;
for (size_t i = 0; i < glyph_count; ++i)
missing += (glyphs[i] == kMissingGlyphId) ? 1 : 0;
return missing;
}
Range TextRunHarfBuzz::GetGraphemeBounds(
base::i18n::BreakIterator* grapheme_iterator,
size_t text_index) {
DCHECK_LT(text_index, range.end());
// TODO(msw): Support floating point grapheme bounds.
const int preceding_run_widths_int = SkScalarRoundToInt(preceding_run_widths);
if (glyph_count == 0)
return Range(preceding_run_widths_int, preceding_run_widths_int + width);
Range chars;
Range glyphs;
GetClusterAt(text_index, &chars, &glyphs);
const int cluster_begin_x = SkScalarRoundToInt(positions[glyphs.start()].x());
const int cluster_end_x = glyphs.end() < glyph_count ?
SkScalarRoundToInt(positions[glyphs.end()].x()) : width;
// A cluster consists of a number of code points and corresponds to a number
// of glyphs that should be drawn together. A cluster can contain multiple
// graphemes. In order to place the cursor at a grapheme boundary inside the
// cluster, we simply divide the cluster width by the number of graphemes.
if (chars.length() > 1 && grapheme_iterator) {
int before = 0;
int total = 0;
for (size_t i = chars.start(); i < chars.end(); ++i) {
if (grapheme_iterator->IsGraphemeBoundary(i)) {
if (i < text_index)
++before;
++total;
}
}
DCHECK_GT(total, 0);
if (total > 1) {
if (is_rtl)
before = total - before - 1;
DCHECK_GE(before, 0);
DCHECK_LT(before, total);
const int cluster_width = cluster_end_x - cluster_begin_x;
const int grapheme_begin_x = cluster_begin_x + static_cast<int>(0.5f +
cluster_width * before / static_cast<float>(total));
const int grapheme_end_x = cluster_begin_x + static_cast<int>(0.5f +
cluster_width * (before + 1) / static_cast<float>(total));
return Range(preceding_run_widths_int + grapheme_begin_x,
preceding_run_widths_int + grapheme_end_x);
}
}
return Range(preceding_run_widths_int + cluster_begin_x,
preceding_run_widths_int + cluster_end_x);
}
} // namespace internal
RenderTextHarfBuzz::RenderTextHarfBuzz()
: RenderText(),
needs_layout_(false) {
set_truncate_length(kMaxTextLength);
}
RenderTextHarfBuzz::~RenderTextHarfBuzz() {}
Size RenderTextHarfBuzz::GetStringSize() {
const SizeF size_f = GetStringSizeF();
return Size(std::ceil(size_f.width()), size_f.height());
}
SizeF RenderTextHarfBuzz::GetStringSizeF() {
EnsureLayout();
return lines()[0].size;
}
SelectionModel RenderTextHarfBuzz::FindCursorPosition(const Point& point) {
EnsureLayout();
int x = ToTextPoint(point).x();
int offset = 0;
size_t run_index = GetRunContainingXCoord(x, &offset);
if (run_index >= runs_.size())
return EdgeSelectionModel((x < 0) ? CURSOR_LEFT : CURSOR_RIGHT);
const internal::TextRunHarfBuzz& run = *runs_[run_index];
for (size_t i = 0; i < run.glyph_count; ++i) {
const SkScalar end =
i + 1 == run.glyph_count ? run.width : run.positions[i + 1].x();
const SkScalar middle = (end + run.positions[i].x()) / 2;
if (offset < middle) {
return SelectionModel(LayoutIndexToTextIndex(
run.glyph_to_char[i] + (run.is_rtl ? 1 : 0)),
(run.is_rtl ? CURSOR_BACKWARD : CURSOR_FORWARD));
}
if (offset < end) {
return SelectionModel(LayoutIndexToTextIndex(
run.glyph_to_char[i] + (run.is_rtl ? 0 : 1)),
(run.is_rtl ? CURSOR_FORWARD : CURSOR_BACKWARD));
}
}
return EdgeSelectionModel(CURSOR_RIGHT);
}
std::vector<RenderText::FontSpan> RenderTextHarfBuzz::GetFontSpansForTesting() {
EnsureLayout();
std::vector<RenderText::FontSpan> spans;
for (size_t i = 0; i < runs_.size(); ++i) {
SkString family_name;
runs_[i]->skia_face->getFamilyName(&family_name);
Font font(family_name.c_str(), runs_[i]->font_size);
spans.push_back(RenderText::FontSpan(font,
Range(LayoutIndexToTextIndex(runs_[i]->range.start()),
LayoutIndexToTextIndex(runs_[i]->range.end()))));
}
return spans;
}
Range RenderTextHarfBuzz::GetGlyphBounds(size_t index) {
EnsureLayout();
const size_t run_index =
GetRunContainingCaret(SelectionModel(index, CURSOR_FORWARD));
// Return edge bounds if the index is invalid or beyond the layout text size.
if (run_index >= runs_.size())
return Range(GetStringSize().width());
const size_t layout_index = TextIndexToLayoutIndex(index);
internal::TextRunHarfBuzz* run = runs_[run_index];
Range bounds = run->GetGraphemeBounds(grapheme_iterator_.get(), layout_index);
return run->is_rtl ? Range(bounds.end(), bounds.start()) : bounds;
}
int RenderTextHarfBuzz::GetLayoutTextBaseline() {
EnsureLayout();
return lines()[0].baseline;
}
SelectionModel RenderTextHarfBuzz::AdjacentCharSelectionModel(
const SelectionModel& selection,
VisualCursorDirection direction) {
DCHECK(!needs_layout_);
internal::TextRunHarfBuzz* run;
size_t run_index = GetRunContainingCaret(selection);
if (run_index >= runs_.size()) {
// The cursor is not in any run: we're at the visual and logical edge.
SelectionModel edge = EdgeSelectionModel(direction);
if (edge.caret_pos() == selection.caret_pos())
return edge;
int visual_index = (direction == CURSOR_RIGHT) ? 0 : runs_.size() - 1;
run = runs_[visual_to_logical_[visual_index]];
} else {
// If the cursor is moving within the current run, just move it by one
// grapheme in the appropriate direction.
run = runs_[run_index];
size_t caret = selection.caret_pos();
bool forward_motion = run->is_rtl == (direction == CURSOR_LEFT);
if (forward_motion) {
if (caret < LayoutIndexToTextIndex(run->range.end())) {
caret = IndexOfAdjacentGrapheme(caret, CURSOR_FORWARD);
return SelectionModel(caret, CURSOR_BACKWARD);
}
} else {
if (caret > LayoutIndexToTextIndex(run->range.start())) {
caret = IndexOfAdjacentGrapheme(caret, CURSOR_BACKWARD);
return SelectionModel(caret, CURSOR_FORWARD);
}
}
// The cursor is at the edge of a run; move to the visually adjacent run.
int visual_index = logical_to_visual_[run_index];
visual_index += (direction == CURSOR_LEFT) ? -1 : 1;
if (visual_index < 0 || visual_index >= static_cast<int>(runs_.size()))
return EdgeSelectionModel(direction);
run = runs_[visual_to_logical_[visual_index]];
}
bool forward_motion = run->is_rtl == (direction == CURSOR_LEFT);
return forward_motion ? FirstSelectionModelInsideRun(run) :
LastSelectionModelInsideRun(run);
}
SelectionModel RenderTextHarfBuzz::AdjacentWordSelectionModel(
const SelectionModel& selection,
VisualCursorDirection direction) {
if (obscured())
return EdgeSelectionModel(direction);
base::i18n::BreakIterator iter(text(), base::i18n::BreakIterator::BREAK_WORD);
bool success = iter.Init();
DCHECK(success);
if (!success)
return selection;
// Match OS specific word break behavior.
#if defined(OS_WIN)
size_t pos;
if (direction == CURSOR_RIGHT) {
pos = std::min(selection.caret_pos() + 1, text().length());
while (iter.Advance()) {
pos = iter.pos();
if (iter.IsWord() && pos > selection.caret_pos())
break;
}
} else { // direction == CURSOR_LEFT
// Notes: We always iterate words from the beginning.
// This is probably fast enough for our usage, but we may
// want to modify WordIterator so that it can start from the
// middle of string and advance backwards.
pos = std::max<int>(selection.caret_pos() - 1, 0);
while (iter.Advance()) {
if (iter.IsWord()) {
size_t begin = iter.pos() - iter.GetString().length();
if (begin == selection.caret_pos()) {
// The cursor is at the beginning of a word.
// Move to previous word.
break;
} else if (iter.pos() >= selection.caret_pos()) {
// The cursor is in the middle or at the end of a word.
// Move to the top of current word.
pos = begin;
break;
}
pos = iter.pos() - iter.GetString().length();
}
}
}
return SelectionModel(pos, CURSOR_FORWARD);
#else
SelectionModel cur(selection);
for (;;) {
cur = AdjacentCharSelectionModel(cur, direction);
size_t run = GetRunContainingCaret(cur);
if (run == runs_.size())
break;
const bool is_forward = runs_[run]->is_rtl == (direction == CURSOR_LEFT);
size_t cursor = cur.caret_pos();
if (is_forward ? iter.IsEndOfWord(cursor) : iter.IsStartOfWord(cursor))
break;
}
return cur;
#endif
}
std::vector<Rect> RenderTextHarfBuzz::GetSubstringBounds(const Range& range) {
DCHECK(!needs_layout_);
DCHECK(Range(0, text().length()).Contains(range));
Range layout_range(TextIndexToLayoutIndex(range.start()),
TextIndexToLayoutIndex(range.end()));
DCHECK(Range(0, GetLayoutText().length()).Contains(layout_range));
std::vector<Rect> rects;
if (layout_range.is_empty())
return rects;
std::vector<Range> bounds;
// Add a Range for each run/selection intersection.
for (size_t i = 0; i < runs_.size(); ++i) {
internal::TextRunHarfBuzz* run = runs_[visual_to_logical_[i]];
Range intersection = run->range.Intersect(layout_range);
if (!intersection.IsValid())
continue;
DCHECK(!intersection.is_reversed());
const Range leftmost_character_x = run->GetGraphemeBounds(
grapheme_iterator_.get(),
run->is_rtl ? intersection.end() - 1 : intersection.start());
const Range rightmost_character_x = run->GetGraphemeBounds(
grapheme_iterator_.get(),
run->is_rtl ? intersection.start() : intersection.end() - 1);
Range range_x(leftmost_character_x.start(), rightmost_character_x.end());
DCHECK(!range_x.is_reversed());
if (range_x.is_empty())
continue;
// Union this with the last range if they're adjacent.
DCHECK(bounds.empty() || bounds.back().GetMax() <= range_x.GetMin());
if (!bounds.empty() && bounds.back().GetMax() == range_x.GetMin()) {
range_x = Range(bounds.back().GetMin(), range_x.GetMax());
bounds.pop_back();
}
bounds.push_back(range_x);
}
for (size_t i = 0; i < bounds.size(); ++i) {
std::vector<Rect> current_rects = TextBoundsToViewBounds(bounds[i]);
rects.insert(rects.end(), current_rects.begin(), current_rects.end());
}
return rects;
}
size_t RenderTextHarfBuzz::TextIndexToLayoutIndex(size_t index) const {
DCHECK_LE(index, text().length());
ptrdiff_t i = obscured() ? UTF16IndexToOffset(text(), 0, index) : index;
CHECK_GE(i, 0);
// Clamp layout indices to the length of the text actually used for layout.
return std::min<size_t>(GetLayoutText().length(), i);
}
size_t RenderTextHarfBuzz::LayoutIndexToTextIndex(size_t index) const {
if (!obscured())
return index;
DCHECK_LE(index, GetLayoutText().length());
const size_t text_index = UTF16OffsetToIndex(text(), 0, index);
DCHECK_LE(text_index, text().length());
return text_index;
}
bool RenderTextHarfBuzz::IsValidCursorIndex(size_t index) {
if (index == 0 || index == text().length())
return true;
if (!IsValidLogicalIndex(index))
return false;
EnsureLayout();
return !grapheme_iterator_ || grapheme_iterator_->IsGraphemeBoundary(index);
}
void RenderTextHarfBuzz::ResetLayout() {
needs_layout_ = true;
}
void RenderTextHarfBuzz::EnsureLayout() {
if (needs_layout_) {
runs_.clear();
grapheme_iterator_.reset();
if (!GetLayoutText().empty()) {
grapheme_iterator_.reset(new base::i18n::BreakIterator(GetLayoutText(),
base::i18n::BreakIterator::BREAK_CHARACTER));
if (!grapheme_iterator_->Init())
grapheme_iterator_.reset();
ItemizeText();
for (size_t i = 0; i < runs_.size(); ++i)
ShapeRun(runs_[i]);
// Precalculate run width information.
float preceding_run_widths = 0.0f;
for (size_t i = 0; i < runs_.size(); ++i) {
internal::TextRunHarfBuzz* run = runs_[visual_to_logical_[i]];
run->preceding_run_widths = preceding_run_widths;
preceding_run_widths += run->width;
}
}
needs_layout_ = false;
std::vector<internal::Line> empty_lines;
set_lines(&empty_lines);
}
if (lines().empty()) {
std::vector<internal::Line> lines;
lines.push_back(internal::Line());
lines[0].baseline = font_list().GetBaseline();
lines[0].size.set_height(font_list().GetHeight());
int current_x = 0;
SkPaint paint;
for (size_t i = 0; i < runs_.size(); ++i) {
const internal::TextRunHarfBuzz& run = *runs_[visual_to_logical_[i]];
internal::LineSegment segment;
segment.x_range = Range(current_x, current_x + run.width);
segment.char_range = run.range;
segment.run = i;
lines[0].segments.push_back(segment);
paint.setTypeface(run.skia_face.get());
paint.setTextSize(run.font_size);
SkPaint::FontMetrics metrics;
paint.getFontMetrics(&metrics);
lines[0].size.set_width(lines[0].size.width() + run.width);
lines[0].size.set_height(std::max(lines[0].size.height(),
metrics.fDescent - metrics.fAscent));
lines[0].baseline = std::max(lines[0].baseline,
SkScalarRoundToInt(-metrics.fAscent));
}
set_lines(&lines);
}
}
void RenderTextHarfBuzz::DrawVisualText(Canvas* canvas) {
DCHECK(!needs_layout_);
internal::SkiaTextRenderer renderer(canvas);
ApplyFadeEffects(&renderer);
ApplyTextShadows(&renderer);
ApplyCompositionAndSelectionStyles();
int current_x = 0;
const Vector2d line_offset = GetLineOffset(0);
for (size_t i = 0; i < runs_.size(); ++i) {
const internal::TextRunHarfBuzz& run = *runs_[visual_to_logical_[i]];
renderer.SetTypeface(run.skia_face.get());
renderer.SetTextSize(run.font_size);
renderer.SetFontRenderParams(run.render_params,
background_is_transparent());
Vector2d origin = line_offset + Vector2d(current_x, lines()[0].baseline);
scoped_ptr<SkPoint[]> positions(new SkPoint[run.glyph_count]);
for (size_t j = 0; j < run.glyph_count; ++j) {
positions[j] = run.positions[j];
positions[j].offset(SkIntToScalar(origin.x()), SkIntToScalar(origin.y()));
}
for (BreakList<SkColor>::const_iterator it =
colors().GetBreak(run.range.start());
it != colors().breaks().end() && it->first < run.range.end();
++it) {
const Range intersection = colors().GetRange(it).Intersect(run.range);
const Range colored_glyphs = run.CharRangeToGlyphRange(intersection);
// The range may be empty if a portion of a multi-character grapheme is
// selected, yielding two colors for a single glyph. For now, this just
// paints the glyph with a single style, but it should paint it twice,
// clipped according to selection bounds. See http://crbug.com/366786
if (colored_glyphs.is_empty())
continue;
renderer.SetForegroundColor(it->second);
renderer.DrawPosText(&positions[colored_glyphs.start()],
&run.glyphs[colored_glyphs.start()],
colored_glyphs.length());
int width = (colored_glyphs.end() == run.glyph_count ? run.width :
run.positions[colored_glyphs.end()].x()) -
run.positions[colored_glyphs.start()].x();
renderer.DrawDecorations(origin.x(), origin.y(), width, run.underline,
run.strike, run.diagonal_strike);
}
current_x += run.width;
}
renderer.EndDiagonalStrike();
UndoCompositionAndSelectionStyles();
}
size_t RenderTextHarfBuzz::GetRunContainingCaret(
const SelectionModel& caret) const {
DCHECK(!needs_layout_);
size_t layout_position = TextIndexToLayoutIndex(caret.caret_pos());
LogicalCursorDirection affinity = caret.caret_affinity();
for (size_t run = 0; run < runs_.size(); ++run) {
if (RangeContainsCaret(runs_[run]->range, layout_position, affinity))
return run;
}
return runs_.size();
}
size_t RenderTextHarfBuzz::GetRunContainingXCoord(int x, int* offset) const {
DCHECK(!needs_layout_);
if (x < 0)
return runs_.size();
// Find the text run containing the argument point (assumed already offset).
int current_x = 0;
for (size_t i = 0; i < runs_.size(); ++i) {
size_t run = visual_to_logical_[i];
current_x += runs_[run]->width;
if (x < current_x) {
*offset = x - (current_x - runs_[run]->width);
return run;
}
}
return runs_.size();
}
SelectionModel RenderTextHarfBuzz::FirstSelectionModelInsideRun(
const internal::TextRunHarfBuzz* run) {
size_t position = LayoutIndexToTextIndex(run->range.start());
position = IndexOfAdjacentGrapheme(position, CURSOR_FORWARD);
return SelectionModel(position, CURSOR_BACKWARD);
}
SelectionModel RenderTextHarfBuzz::LastSelectionModelInsideRun(
const internal::TextRunHarfBuzz* run) {
size_t position = LayoutIndexToTextIndex(run->range.end());
position = IndexOfAdjacentGrapheme(position, CURSOR_BACKWARD);
return SelectionModel(position, CURSOR_FORWARD);
}
void RenderTextHarfBuzz::ItemizeText() {
const base::string16& text = GetLayoutText();
const bool is_text_rtl = GetTextDirection() == base::i18n::RIGHT_TO_LEFT;
DCHECK_NE(0U, text.length());
// If ICU fails to itemize the text, we create a run that spans the entire
// text. This is needed because leaving the runs set empty causes some clients
// to misbehave since they expect non-zero text metrics from a non-empty text.
base::i18n::BiDiLineIterator bidi_iterator;
if (!bidi_iterator.Open(text, is_text_rtl, false)) {
internal::TextRunHarfBuzz* run = new internal::TextRunHarfBuzz;
run->range = Range(0, text.length());
runs_.push_back(run);
visual_to_logical_ = logical_to_visual_ = std::vector<int32_t>(1, 0);
return;
}
// Temporarily apply composition underlines and selection colors.
ApplyCompositionAndSelectionStyles();
// Build the list of runs from the script items and ranged styles. Use an
// empty color BreakList to avoid breaking runs at color boundaries.
BreakList<SkColor> empty_colors;
empty_colors.SetMax(text.length());
internal::StyleIterator style(empty_colors, styles());
for (size_t run_break = 0; run_break < text.length();) {
internal::TextRunHarfBuzz* run = new internal::TextRunHarfBuzz;
run->range.set_start(run_break);
run->font_style = (style.style(BOLD) ? Font::BOLD : 0) |
(style.style(ITALIC) ? Font::ITALIC : 0);
run->strike = style.style(STRIKE);
run->diagonal_strike = style.style(DIAGONAL_STRIKE);
run->underline = style.style(UNDERLINE);
int32 script_item_break = 0;
bidi_iterator.GetLogicalRun(run_break, &script_item_break, &run->level);
// Odd BiDi embedding levels correspond to RTL runs.
run->is_rtl = (run->level % 2) == 1;
// Find the length and script of this script run.
script_item_break = ScriptInterval(text, run_break,
script_item_break - run_break, &run->script) + run_break;
// Find the next break and advance the iterators as needed.
run_break = std::min(static_cast<size_t>(script_item_break),
TextIndexToLayoutIndex(style.GetRange().end()));
// Break runs at certain characters that need to be rendered separately to
// prevent either an unusual character from forcing a fallback font on the
// entire run, or brackets from being affected by a fallback font.
// http://crbug.com/278913, http://crbug.com/396776
if (run_break > run->range.start())
run_break = FindRunBreakingCharacter(text, run->range.start(), run_break);
DCHECK(IsValidCodePointIndex(text, run_break));
style.UpdatePosition(LayoutIndexToTextIndex(run_break));
run->range.set_end(run_break);
runs_.push_back(run);
}
// Undo the temporarily applied composition underlines and selection colors.
UndoCompositionAndSelectionStyles();
const size_t num_runs = runs_.size();
std::vector<UBiDiLevel> levels(num_runs);
for (size_t i = 0; i < num_runs; ++i)
levels[i] = runs_[i]->level;
visual_to_logical_.resize(num_runs);
ubidi_reorderVisual(&levels[0], num_runs, &visual_to_logical_[0]);
logical_to_visual_.resize(num_runs);
ubidi_reorderLogical(&levels[0], num_runs, &logical_to_visual_[0]);
}
void RenderTextHarfBuzz::ShapeRun(internal::TextRunHarfBuzz* run) {
const Font& primary_font = font_list().GetPrimaryFont();
const std::string primary_font_name = primary_font.GetFontName();
run->font_size = primary_font.GetFontSize();
size_t best_font_missing = std::numeric_limits<size_t>::max();
std::string best_font;
std::string current_font;
// Try shaping with |primary_font|.
if (ShapeRunWithFont(run, primary_font_name)) {
current_font = primary_font_name;
size_t current_missing = run->CountMissingGlyphs();
if (current_missing == 0)
return;
if (current_missing < best_font_missing) {
best_font_missing = current_missing;
best_font = current_font;
}
}
#if defined(OS_WIN)
Font uniscribe_font;
const base::char16* run_text = &(GetLayoutText()[run->range.start()]);
if (GetUniscribeFallbackFont(primary_font, run_text, run->range.length(),
&uniscribe_font) &&
ShapeRunWithFont(run, uniscribe_font.GetFontName())) {
current_font = uniscribe_font.GetFontName();
size_t current_missing = run->CountMissingGlyphs();
if (current_missing == 0)
return;
if (current_missing < best_font_missing) {
best_font_missing = current_missing;
best_font = current_font;
}
}
#endif
// Try shaping with the fonts in the fallback list except the first, which is
// |primary_font|.
std::vector<std::string> fonts = GetFallbackFontFamilies(primary_font_name);
for (size_t i = 1; i < fonts.size(); ++i) {
if (!ShapeRunWithFont(run, fonts[i]))
continue;
current_font = fonts[i];
size_t current_missing = run->CountMissingGlyphs();
if (current_missing == 0)
return;
if (current_missing < best_font_missing) {
best_font_missing = current_missing;
best_font = current_font;
}
}
if (!best_font.empty() &&
(best_font == current_font || ShapeRunWithFont(run, best_font))) {
return;
}
run->glyph_count = 0;
run->width = 0.0f;
}
bool RenderTextHarfBuzz::ShapeRunWithFont(internal::TextRunHarfBuzz* run,
const std::string& font_family) {
const base::string16& text = GetLayoutText();
skia::RefPtr<SkTypeface> skia_face =
internal::CreateSkiaTypeface(font_family, run->font_style);
if (skia_face == NULL)
return false;
run->skia_face = skia_face;
FontRenderParamsQuery query(false);
query.families.push_back(font_family);
query.pixel_size = run->font_size;
query.style = run->font_style;
run->render_params = GetFontRenderParams(query, NULL);
hb_font_t* harfbuzz_font = CreateHarfBuzzFont(run->skia_face.get(),
run->font_size, run->render_params, background_is_transparent());
// Create a HarfBuzz buffer and add the string to be shaped. The HarfBuzz
// buffer holds our text, run information to be used by the shaping engine,
// and the resulting glyph data.
hb_buffer_t* buffer = hb_buffer_create();
hb_buffer_add_utf16(buffer, reinterpret_cast<const uint16*>(text.c_str()),
text.length(), run->range.start(), run->range.length());
hb_buffer_set_script(buffer, ICUScriptToHBScript(run->script));
hb_buffer_set_direction(buffer,
run->is_rtl ? HB_DIRECTION_RTL : HB_DIRECTION_LTR);
// TODO(ckocagil): Should we determine the actual language?
hb_buffer_set_language(buffer, hb_language_get_default());
// Shape the text.
hb_shape(harfbuzz_font, buffer, NULL, 0);
// Populate the run fields with the resulting glyph data in the buffer.
unsigned int glyph_count = 0;
hb_glyph_info_t* infos = hb_buffer_get_glyph_infos(buffer, &glyph_count);
run->glyph_count = glyph_count;
hb_glyph_position_t* hb_positions =
hb_buffer_get_glyph_positions(buffer, NULL);
run->glyphs.reset(new uint16[run->glyph_count]);
run->glyph_to_char.resize(run->glyph_count);
run->positions.reset(new SkPoint[run->glyph_count]);
run->width = 0.0f;
for (size_t i = 0; i < run->glyph_count; ++i) {
run->glyphs[i] = infos[i].codepoint;
run->glyph_to_char[i] = infos[i].cluster;
const int x_offset = SkFixedToScalar(hb_positions[i].x_offset);
const int y_offset = SkFixedToScalar(hb_positions[i].y_offset);
run->positions[i].set(run->width + x_offset, -y_offset);
run->width += SkFixedToScalar(hb_positions[i].x_advance);
#if defined(OS_LINUX)
// Match Pango's glyph rounding logic on Linux.
if (!run->render_params.subpixel_positioning)
run->width = std::floor(run->width + 0.5f);
#endif
}
hb_buffer_destroy(buffer);
hb_font_destroy(harfbuzz_font);
return true;
}
} // namespace gfx