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android / platform / external / chromium_org / 0bdaf95291fc46702f274f40e8e5081e9ef23011 / . / ui / gfx / render_text_win.cc
blob: dfcff0e432d9f35a7c8e9e6852bec2b5a9d7a886 [file] [log] [blame]
// Copyright (c) 2012 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_win.h"
#include <algorithm>
#include "base/i18n/break_iterator.h"
#include "base/i18n/rtl.h"
#include "base/logging.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/win/windows_version.h"
#include "third_party/icu/source/common/unicode/uchar.h"
#include "ui/gfx/canvas.h"
#include "ui/gfx/font_fallback_win.h"
#include "ui/gfx/font_smoothing_win.h"
#include "ui/gfx/platform_font_win.h"
#include "ui/gfx/utf16_indexing.h"
namespace gfx {
namespace {
// The maximum length of text supported for Uniscribe layout and display.
// This empirically chosen value should prevent major performance degradations.
// TODO(msw): Support longer text, partial layout/painting, etc.
const size_t kMaxUniscribeTextLength = 10000;
// The initial guess and maximum supported number of runs; arbitrary values.
// TODO(msw): Support more runs, determine a better initial guess, etc.
const int kGuessRuns = 100;
const size_t kMaxRuns = 10000;
// The maximum number of glyphs per run; ScriptShape fails on larger values.
const size_t kMaxGlyphs = 65535;
// Callback to |EnumEnhMetaFile()| to intercept font creation.
int CALLBACK MetaFileEnumProc(HDC hdc,
HANDLETABLE* table,
CONST ENHMETARECORD* record,
int table_entries,
LPARAM log_font) {
if (record->iType == EMR_EXTCREATEFONTINDIRECTW) {
const EMREXTCREATEFONTINDIRECTW* create_font_record =
reinterpret_cast<const EMREXTCREATEFONTINDIRECTW*>(record);
*reinterpret_cast<LOGFONT*>(log_font) = create_font_record->elfw.elfLogFont;
}
return 1;
}
// Finds a fallback font to use to render the specified |text| with respect to
// an initial |font|. Returns the resulting font via out param |result|. Returns
// |true| if a fallback font was found.
// Adapted from WebKit's |FontCache::GetFontDataForCharacters()|.
// TODO(asvitkine): This should be moved to font_fallback_win.cc.
bool ChooseFallbackFont(HDC hdc,
const Font& font,
const wchar_t* text,
int text_length,
Font* result) {
// Use a meta file to intercept the fallback font chosen by Uniscribe.
HDC meta_file_dc = CreateEnhMetaFile(hdc, NULL, NULL, NULL);
if (!meta_file_dc)
return false;
SelectObject(meta_file_dc, font.GetNativeFont());
SCRIPT_STRING_ANALYSIS script_analysis;
HRESULT hresult =
ScriptStringAnalyse(meta_file_dc, text, text_length, 0, -1,
SSA_METAFILE | SSA_FALLBACK | SSA_GLYPHS | SSA_LINK,
0, NULL, NULL, NULL, NULL, NULL, &script_analysis);
if (SUCCEEDED(hresult)) {
hresult = ScriptStringOut(script_analysis, 0, 0, 0, NULL, 0, 0, FALSE);
ScriptStringFree(&script_analysis);
}
bool found_fallback = false;
HENHMETAFILE meta_file = CloseEnhMetaFile(meta_file_dc);
if (SUCCEEDED(hresult)) {
LOGFONT log_font;
log_font.lfFaceName[0] = 0;
EnumEnhMetaFile(0, meta_file, MetaFileEnumProc, &log_font, NULL);
if (log_font.lfFaceName[0]) {
*result = Font(UTF16ToUTF8(log_font.lfFaceName), font.GetFontSize());
found_fallback = true;
}
}
DeleteEnhMetaFile(meta_file);
return found_fallback;
}
// Changes |font| to have the specified |font_size| (or |font_height| on Windows
// XP) and |font_style| if it is not the case already. Only considers bold and
// italic styles, since the underlined style has no effect on glyph shaping.
void DeriveFontIfNecessary(int font_size,
int font_height,
int font_style,
Font* font) {
const int kStyleMask = (Font::BOLD | Font::ITALIC);
const int target_style = (font_style & kStyleMask);
// On Windows XP, the font must be resized using |font_height| instead of
// |font_size| to match GDI behavior.
if (base::win::GetVersion() < base::win::VERSION_VISTA) {
PlatformFontWin* platform_font =
static_cast<PlatformFontWin*>(font->platform_font());
*font = platform_font->DeriveFontWithHeight(font_height, target_style);
return;
}
const int current_style = (font->GetStyle() & kStyleMask);
const int current_size = font->GetFontSize();
if (current_style != target_style || current_size != font_size)
*font = font->DeriveFont(font_size - current_size, target_style);
}
// Returns true if |c| is a Unicode BiDi control character.
bool IsUnicodeBidiControlCharacter(char16 c) {
return c == base::i18n::kRightToLeftMark ||
c == base::i18n::kLeftToRightMark ||
c == base::i18n::kLeftToRightEmbeddingMark ||
c == base::i18n::kRightToLeftEmbeddingMark ||
c == base::i18n::kPopDirectionalFormatting ||
c == base::i18n::kLeftToRightOverride ||
c == base::i18n::kRightToLeftOverride;
}
// Returns the corresponding glyph range of the given character range.
// |range| is in text-space (0 corresponds to |GetLayoutText()[0]|).
// Returned value is in run-space (0 corresponds to the first glyph in the run).
Range CharRangeToGlyphRange(const internal::TextRun& run,
const Range& range) {
DCHECK(run.range.Contains(range));
DCHECK(!range.is_reversed());
DCHECK(!range.is_empty());
const Range run_range(range.start() - run.range.start(),
range.end() - run.range.start());
Range result;
if (run.script_analysis.fRTL) {
result = Range(run.logical_clusters[run_range.end() - 1],
run_range.start() > 0 ? run.logical_clusters[run_range.start() - 1]
: run.glyph_count);
} else {
result = Range(run.logical_clusters[run_range.start()],
run_range.end() < run.range.length() ?
run.logical_clusters[run_range.end()] : run.glyph_count);
}
DCHECK(!result.is_reversed());
DCHECK(Range(0, run.glyph_count).Contains(result));
return result;
}
// Starting from |start_char|, finds a suitable line break position at or before
// |available_width| using word break info from |breaks|. If |empty_line| is
// true, this function will not roll back to |start_char| and |*next_char| will
// be greater than |start_char| (to avoid constructing empty lines).
// TODO(ckocagil): Do not break ligatures and diacritics.
// TextRun::logical_clusters might help.
// TODO(ckocagil): We might have to reshape after breaking at ligatures.
// See whether resolving the TODO above resolves this too.
// TODO(ckocagil): Do not reserve width for whitespace at the end of lines.
void BreakRunAtWidth(const internal::TextRun& run,
const BreakList<size_t>& breaks,
size_t start_char,
int available_width,
bool empty_line,
int* width,
size_t* next_char) {
DCHECK(run.range.Contains(Range(start_char, start_char + 1)));
BreakList<size_t>::const_iterator word = breaks.GetBreak(start_char);
BreakList<size_t>::const_iterator next_word = word + 1;
// Width from |std::max(word->first, start_char)| to the current character.
int word_width = 0;
*width = 0;
for (size_t i = start_char; i < run.range.end(); ++i) {
// |word| holds the word boundary at or before |i|, and |next_word| holds
// the word boundary right after |i|. Advance both |word| and |next_word|
// when |i| reaches |next_word|.
if (next_word != breaks.breaks().end() && i >= next_word->first) {
word = next_word++;
word_width = 0;
}
Range glyph_range = CharRangeToGlyphRange(run, Range(i, i + 1));
int char_width = 0;
for (size_t j = glyph_range.start(); j < glyph_range.end(); ++j)
char_width += run.advance_widths[j];
*width += char_width;
word_width += char_width;
if (*width > available_width) {
if (!empty_line || word_width < *width) {
*width -= word_width;
*next_char = std::max(word->first, start_char);
} else if (char_width < *width) {
*width -= char_width;
*next_char = i;
} else {
*next_char = i + 1;
}
return;
}
}
*next_char = run.range.end();
}
// For segments in the same run, checks the continuity and order of |x_range|
// and |char_range| fields.
void CheckLineIntegrity(const std::vector<internal::Line>& lines,
const ScopedVector<internal::TextRun>& runs) {
size_t previous_segment_line = 0;
const internal::LineSegment* previous_segment = NULL;
for (size_t i = 0; i < lines.size(); ++i) {
for (size_t j = 0; j < lines[i].segments.size(); ++j) {
const internal::LineSegment* segment = &lines[i].segments[j];
internal::TextRun* run = runs[segment->run];
if (!previous_segment) {
previous_segment = segment;
} else if (runs[previous_segment->run] != run) {
previous_segment = NULL;
} else {
DCHECK_EQ(previous_segment->char_range.end(),
segment->char_range.start());
if (!run->script_analysis.fRTL) {
DCHECK_EQ(previous_segment->x_range.end(), segment->x_range.start());
} else {
DCHECK_EQ(segment->x_range.end(), previous_segment->x_range.start());
}
previous_segment = segment;
previous_segment_line = i;
}
}
}
}
} // namespace
namespace internal {
TextRun::TextRun()
: font_style(0),
strike(false),
diagonal_strike(false),
underline(false),
width(0),
preceding_run_widths(0),
glyph_count(0),
script_cache(NULL) {
memset(&script_analysis, 0, sizeof(script_analysis));
memset(&abc_widths, 0, sizeof(abc_widths));
}
TextRun::~TextRun() {
ScriptFreeCache(&script_cache);
}
// Returns the X coordinate of the leading or |trailing| edge of the glyph
// starting at |index|, relative to the left of the text (not the view).
int GetGlyphXBoundary(const internal::TextRun* run,
size_t index,
bool trailing) {
DCHECK_GE(index, run->range.start());
DCHECK_LT(index, run->range.end() + (trailing ? 0 : 1));
int x = 0;
HRESULT hr = ScriptCPtoX(
index - run->range.start(),
trailing,
run->range.length(),
run->glyph_count,
run->logical_clusters.get(),
run->visible_attributes.get(),
run->advance_widths.get(),
&run->script_analysis,
&x);
DCHECK(SUCCEEDED(hr));
return run->preceding_run_widths + x;
}
// Internal class to generate Line structures. If |multiline| is true, the text
// is broken into lines at |words| boundaries such that each line is no longer
// than |max_width|. If |multiline| is false, only outputs a single Line from
// the given runs. |min_baseline| and |min_height| are the minimum baseline and
// height for each line.
// TODO(ckocagil): Expose the interface of this class in the header and test
// this class directly.
class LineBreaker {
public:
LineBreaker(int max_width,
int min_baseline,
int min_height,
bool multiline,
const BreakList<size_t>* words,
const ScopedVector<TextRun>& runs)
: max_width_(max_width),
min_baseline_(min_baseline),
min_height_(min_height),
multiline_(multiline),
words_(words),
runs_(runs),
text_x_(0),
line_x_(0),
line_ascent_(0),
line_descent_(0) {
AdvanceLine();
}
// Breaks the run at given |run_index| into Line structs.
void AddRun(int run_index) {
const TextRun* run = runs_[run_index];
if (multiline_ && line_x_ + run->width > max_width_)
BreakRun(run_index);
else
AddSegment(run_index, run->range, run->width);
}
// Finishes line breaking and outputs the results. Can be called at most once.
void Finalize(std::vector<Line>* lines, Size* size) {
DCHECK(!lines_.empty());
// Add an empty line to finish the line size calculation and remove it.
AdvanceLine();
lines_.pop_back();
*size = total_size_;
lines->swap(lines_);
}
private:
// A (line index, segment index) pair that specifies a segment in |lines_|.
typedef std::pair<size_t, size_t> SegmentHandle;
LineSegment* SegmentFromHandle(const SegmentHandle& handle) {
return &lines_[handle.first].segments[handle.second];
}
// Breaks a run into segments that fit in the last line in |lines_| and adds
// them. Adds a new Line to the back of |lines_| whenever a new segment can't
// be added without the Line's width exceeding |max_width_|.
void BreakRun(int run_index) {
DCHECK(words_);
const TextRun* const run = runs_[run_index];
int width = 0;
size_t next_char = run->range.start();
// Break the run until it fits the current line.
while (next_char < run->range.end()) {
const size_t current_char = next_char;
BreakRunAtWidth(*run, *words_, current_char, max_width_ - line_x_,
line_x_ == 0, &width, &next_char);
AddSegment(run_index, Range(current_char, next_char), width);
if (next_char < run->range.end())
AdvanceLine();
}
}
// RTL runs are broken in logical order but displayed in visual order. To find
// the text-space coordinate (where it would fall in a single-line text)
// |x_range| of RTL segments, segment widths are applied in reverse order.
// e.g. {[5, 10], [10, 40]} will become {[35, 40], [5, 35]}.
void UpdateRTLSegmentRanges() {
if (rtl_segments_.empty())
return;
int x = SegmentFromHandle(rtl_segments_[0])->x_range.start();
for (size_t i = rtl_segments_.size(); i > 0; --i) {
LineSegment* segment = SegmentFromHandle(rtl_segments_[i - 1]);
const size_t segment_width = segment->x_range.length();
segment->x_range = Range(x, x + segment_width);
x += segment_width;
}
rtl_segments_.clear();
}
// Finishes the size calculations of the last Line in |lines_|. Adds a new
// Line to the back of |lines_|.
void AdvanceLine() {
if (!lines_.empty()) {
Line* line = &lines_.back();
// TODO(ckocagil): Determine optimal multiline height behavior.
if (line_ascent_ + line_descent_ == 0) {
line_ascent_ = min_baseline_;
line_descent_ = min_height_ - min_baseline_;
}
// Set the single-line mode Line's metrics to be at least
// |RenderText::font_list()| to not break the current single-line code.
line_ascent_ = std::max(line_ascent_, min_baseline_);
line_descent_ = std::max(line_descent_, min_height_ - min_baseline_);
line->baseline = line_ascent_;
line->size.set_height(line_ascent_ + line_descent_);
line->preceding_heights = total_size_.height();
total_size_.set_height(total_size_.height() + line->size.height());
total_size_.set_width(std::max(total_size_.width(), line->size.width()));
}
line_x_ = 0;
line_ascent_ = 0;
line_descent_ = 0;
lines_.push_back(Line());
}
// Adds a new segment with the given properties to |lines_.back()|.
void AddSegment(int run_index, Range char_range, int width) {
if (char_range.is_empty()) {
DCHECK_EQ(width, 0);
return;
}
const TextRun* run = runs_[run_index];
line_ascent_ = std::max(line_ascent_, run->font.GetBaseline());
line_descent_ = std::max(line_descent_,
run->font.GetHeight() - run->font.GetBaseline());
LineSegment segment;
segment.run = run_index;
segment.char_range = char_range;
segment.x_range = Range(text_x_, text_x_ + width);
Line* line = &lines_.back();
line->segments.push_back(segment);
line->size.set_width(line->size.width() + segment.x_range.length());
if (run->script_analysis.fRTL) {
rtl_segments_.push_back(SegmentHandle(lines_.size() - 1,
line->segments.size() - 1));
// If this is the last segment of an RTL run, reprocess the text-space x
// ranges of all segments from the run.
if (char_range.end() == run->range.end())
UpdateRTLSegmentRanges();
}
text_x_ += width;
line_x_ += width;
}
const int max_width_;
const int min_baseline_;
const int min_height_;
const bool multiline_;
const BreakList<size_t>* const words_;
const ScopedVector<TextRun>& runs_;
// Stores the resulting lines.
std::vector<Line> lines_;
// Text space and line space x coordinates of the next segment to be added.
int text_x_;
int line_x_;
// Size of the multiline text, not including the currently processed line.
Size total_size_;
// Ascent and descent values of the current line, |lines_.back()|.
int line_ascent_;
int line_descent_;
// The current RTL run segments, to be applied by |UpdateRTLSegmentRanges()|.
std::vector<SegmentHandle> rtl_segments_;
DISALLOW_COPY_AND_ASSIGN(LineBreaker);
};
} // namespace internal
// static
HDC RenderTextWin::cached_hdc_ = NULL;
// static
std::map<std::string, Font> RenderTextWin::successful_substitute_fonts_;
RenderTextWin::RenderTextWin()
: RenderText(),
needs_layout_(false) {
set_truncate_length(kMaxUniscribeTextLength);
memset(&script_control_, 0, sizeof(script_control_));
memset(&script_state_, 0, sizeof(script_state_));
MoveCursorTo(EdgeSelectionModel(CURSOR_LEFT));
}
RenderTextWin::~RenderTextWin() {
}
Size RenderTextWin::GetStringSize() {
EnsureLayout();
return multiline_string_size_;
}
int RenderTextWin::GetBaseline() {
EnsureLayout();
return lines()[0].baseline;
}
SelectionModel RenderTextWin::FindCursorPosition(const Point& point) {
if (text().empty())
return SelectionModel();
EnsureLayout();
// Find the run that contains the point and adjust the argument location.
int x = ToTextPoint(point).x();
size_t run_index = GetRunContainingXCoord(x);
if (run_index >= runs_.size())
return EdgeSelectionModel((x < 0) ? CURSOR_LEFT : CURSOR_RIGHT);
internal::TextRun* run = runs_[run_index];
int position = 0, trailing = 0;
HRESULT hr = ScriptXtoCP(x - run->preceding_run_widths,
run->range.length(),
run->glyph_count,
run->logical_clusters.get(),
run->visible_attributes.get(),
run->advance_widths.get(),
&(run->script_analysis),
&position,
&trailing);
DCHECK(SUCCEEDED(hr));
DCHECK_GE(trailing, 0);
position += run->range.start();
const size_t cursor = LayoutIndexToTextIndex(position + trailing);
DCHECK_LE(cursor, text().length());
return SelectionModel(cursor, trailing ? CURSOR_BACKWARD : CURSOR_FORWARD);
}
std::vector<RenderText::FontSpan> RenderTextWin::GetFontSpansForTesting() {
EnsureLayout();
std::vector<RenderText::FontSpan> spans;
for (size_t i = 0; i < runs_.size(); ++i) {
spans.push_back(RenderText::FontSpan(runs_[i]->font,
Range(LayoutIndexToTextIndex(runs_[i]->range.start()),
LayoutIndexToTextIndex(runs_[i]->range.end()))));
}
return spans;
}
SelectionModel RenderTextWin::AdjacentCharSelectionModel(
const SelectionModel& selection,
VisualCursorDirection direction) {
DCHECK(!needs_layout_);
internal::TextRun* 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->script_analysis.fRTL == (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->script_analysis.fRTL == (direction == CURSOR_LEFT);
return forward_motion ? FirstSelectionModelInsideRun(run) :
LastSelectionModelInsideRun(run);
}
// TODO(msw): Implement word breaking for Windows.
SelectionModel RenderTextWin::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;
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;
} else {
pos = iter.pos() - iter.GetString().length();
}
}
}
}
return SelectionModel(pos, CURSOR_FORWARD);
}
Range RenderTextWin::GetGlyphBounds(size_t index) {
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(string_width_);
internal::TextRun* run = runs_[run_index];
const size_t layout_index = TextIndexToLayoutIndex(index);
return Range(GetGlyphXBoundary(run, layout_index, false),
GetGlyphXBoundary(run, layout_index, true));
}
std::vector<Rect> RenderTextWin::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.
// TODO(msw): The bounds should probably not always be leading the range ends.
for (size_t i = 0; i < runs_.size(); ++i) {
const internal::TextRun* run = runs_[visual_to_logical_[i]];
Range intersection = run->range.Intersect(layout_range);
if (intersection.IsValid()) {
DCHECK(!intersection.is_reversed());
Range range_x(GetGlyphXBoundary(run, intersection.start(), false),
GetGlyphXBoundary(run, intersection.end(), false));
if (range_x.is_empty())
continue;
range_x = Range(range_x.GetMin(), range_x.GetMax());
// 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 RenderTextWin::TextIndexToLayoutIndex(size_t index) const {
DCHECK_LE(index, text().length());
ptrdiff_t i = obscured() ? gfx::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 RenderTextWin::LayoutIndexToTextIndex(size_t index) const {
if (!obscured())
return index;
DCHECK_LE(index, GetLayoutText().length());
const size_t text_index = gfx::UTF16OffsetToIndex(text(), 0, index);
DCHECK_LE(text_index, text().length());
return text_index;
}
bool RenderTextWin::IsCursorablePosition(size_t position) {
if (position == 0 || position == text().length())
return true;
EnsureLayout();
// Check that the index is at a valid code point (not mid-surrgate-pair),
// that it is not truncated from layout text (its glyph is shown on screen),
// and that its glyph has distinct bounds (not mid-multi-character-grapheme).
// An example of a multi-character-grapheme that is not a surrogate-pair is:
// \x0915\x093f - (ki) - one of many Devanagari biconsonantal conjuncts.
return gfx::IsValidCodePointIndex(text(), position) &&
position < LayoutIndexToTextIndex(GetLayoutText().length()) &&
GetGlyphBounds(position) != GetGlyphBounds(position - 1);
}
void RenderTextWin::ResetLayout() {
// Layout is performed lazily as needed for drawing/metrics.
needs_layout_ = true;
}
void RenderTextWin::EnsureLayout() {
if (needs_layout_) {
// TODO(msw): Skip complex processing if ScriptIsComplex returns false.
ItemizeLogicalText();
if (!runs_.empty())
LayoutVisualText();
needs_layout_ = false;
std::vector<internal::Line> lines;
set_lines(&lines);
}
// Compute lines if they're not valid. This is separate from the layout steps
// above to avoid text layout and shaping when we resize |display_rect_|.
if (lines().empty()) {
DCHECK(!needs_layout_);
std::vector<internal::Line> lines;
internal::LineBreaker line_breaker(display_rect().width() - 1,
font_list().GetBaseline(),
font_list().GetHeight(), multiline(),
multiline() ? &GetLineBreaks() : NULL,
runs_);
for (size_t i = 0; i < runs_.size(); ++i)
line_breaker.AddRun(visual_to_logical_[i]);
line_breaker.Finalize(&lines, &multiline_string_size_);
DCHECK(!lines.empty());
#ifndef NDEBUG
CheckLineIntegrity(lines, runs_);
#endif
set_lines(&lines);
}
}
void RenderTextWin::DrawVisualText(Canvas* canvas) {
DCHECK(!needs_layout_);
DCHECK(!lines().empty());
std::vector<SkPoint> pos;
internal::SkiaTextRenderer renderer(canvas);
ApplyFadeEffects(&renderer);
ApplyTextShadows(&renderer);
bool smoothing_enabled;
bool cleartype_enabled;
GetCachedFontSmoothingSettings(&smoothing_enabled, &cleartype_enabled);
// Note that |cleartype_enabled| corresponds to Skia's |enable_lcd_text|.
renderer.SetFontSmoothingSettings(
smoothing_enabled, cleartype_enabled && !background_is_transparent());
ApplyCompositionAndSelectionStyles();
for (size_t i = 0; i < lines().size(); ++i) {
const internal::Line& line = lines()[i];
const Vector2d line_offset = GetLineOffset(i);
// Skip painting empty lines or lines outside the display rect area.
if (!display_rect().Intersects(Rect(PointAtOffsetFromOrigin(line_offset),
line.size)))
continue;
const Vector2d text_offset = line_offset + Vector2d(0, line.baseline);
int preceding_segment_widths = 0;
for (size_t j = 0; j < line.segments.size(); ++j) {
const internal::LineSegment* segment = &line.segments[j];
const int segment_width = segment->x_range.length();
const internal::TextRun* run = runs_[segment->run];
DCHECK(!segment->char_range.is_empty());
DCHECK(run->range.Contains(segment->char_range));
Range glyph_range = CharRangeToGlyphRange(*run, segment->char_range);
DCHECK(!glyph_range.is_empty());
// Skip painting segments outside the display rect area.
if (!multiline()) {
const Rect segment_bounds(PointAtOffsetFromOrigin(line_offset) +
Vector2d(preceding_segment_widths, 0),
Size(segment_width, line.size.height()));
if (!display_rect().Intersects(segment_bounds)) {
preceding_segment_widths += segment_width;
continue;
}
}
// |pos| contains the positions of glyphs. An extra terminal |pos| entry
// is added to simplify width calculations.
int segment_x = preceding_segment_widths;
pos.resize(glyph_range.length() + 1);
for (size_t k = glyph_range.start(); k < glyph_range.end(); ++k) {
pos[k - glyph_range.start()].set(
SkIntToScalar(text_offset.x() + run->offsets[k].du + segment_x),
SkIntToScalar(text_offset.y() + run->offsets[k].dv));
segment_x += run->advance_widths[k];
}
pos.back().set(SkIntToScalar(text_offset.x() + segment_x),
SkIntToScalar(text_offset.y()));
renderer.SetTextSize(run->font.GetFontSize());
renderer.SetFontFamilyWithStyle(run->font.GetFontName(), run->font_style);
for (BreakList<SkColor>::const_iterator it =
colors().GetBreak(segment->char_range.start());
it != colors().breaks().end() &&
it->first < segment->char_range.end();
++it) {
const Range intersection =
colors().GetRange(it).Intersect(segment->char_range);
const Range colored_glyphs = CharRangeToGlyphRange(*run, intersection);
DCHECK(glyph_range.Contains(colored_glyphs));
DCHECK(!colored_glyphs.is_empty());
const SkPoint& start_pos =
pos[colored_glyphs.start() - glyph_range.start()];
const SkPoint& end_pos =
pos[colored_glyphs.end() - glyph_range.start()];
renderer.SetForegroundColor(it->second);
renderer.DrawPosText(&start_pos, &run->glyphs[colored_glyphs.start()],
colored_glyphs.length());
renderer.DrawDecorations(start_pos.x(), text_offset.y(),
SkScalarCeilToInt(end_pos.x() - start_pos.x()),
run->underline, run->strike,
run->diagonal_strike);
}
preceding_segment_widths += segment_width;
}
}
UndoCompositionAndSelectionStyles();
}
void RenderTextWin::ItemizeLogicalText() {
runs_.clear();
string_width_ = 0;
multiline_string_size_ = Size();
// Set Uniscribe's base text direction.
script_state_.uBidiLevel =
(GetTextDirection() == base::i18n::RIGHT_TO_LEFT) ? 1 : 0;
if (text().empty())
return;
HRESULT hr = E_OUTOFMEMORY;
int script_items_count = 0;
std::vector<SCRIPT_ITEM> script_items;
const size_t layout_text_length = GetLayoutText().length();
// Ensure that |kMaxRuns| is attempted and the loop terminates afterward.
for (size_t runs = kGuessRuns; hr == E_OUTOFMEMORY && runs <= kMaxRuns;
runs = std::max(runs + 1, std::min(runs * 2, kMaxRuns))) {
// Derive the array of Uniscribe script items from the logical text.
// ScriptItemize always adds a terminal array item so that the length of
// the last item can be derived from the terminal SCRIPT_ITEM::iCharPos.
script_items.resize(runs);
hr = ScriptItemize(GetLayoutText().c_str(), layout_text_length,
runs - 1, &script_control_, &script_state_,
&script_items[0], &script_items_count);
}
DCHECK(SUCCEEDED(hr));
if (!SUCCEEDED(hr) || script_items_count <= 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());
SCRIPT_ITEM* script_item = &script_items[0];
const size_t max_run_length = kMaxGlyphs / 2;
for (size_t run_break = 0; run_break < layout_text_length;) {
internal::TextRun* run = new internal::TextRun();
run->range.set_start(run_break);
run->font = GetPrimaryFont();
run->font_style = (style.style(BOLD) ? Font::BOLD : 0) |
(style.style(ITALIC) ? Font::ITALIC : 0);
DeriveFontIfNecessary(run->font.GetFontSize(), run->font.GetHeight(),
run->font_style, &run->font);
run->strike = style.style(STRIKE);
run->diagonal_strike = style.style(DIAGONAL_STRIKE);
run->underline = style.style(UNDERLINE);
run->script_analysis = script_item->a;
// Find the next break and advance the iterators as needed.
const size_t script_item_break = (script_item + 1)->iCharPos;
run_break = std::min(script_item_break,
TextIndexToLayoutIndex(style.GetRange().end()));
// Clamp run lengths to avoid exceeding the maximum supported glyph count.
if ((run_break - run->range.start()) > max_run_length)
run_break = run->range.start() + max_run_length;
style.UpdatePosition(LayoutIndexToTextIndex(run_break));
if (script_item_break == run_break)
script_item++;
run->range.set_end(run_break);
runs_.push_back(run);
}
// Undo the temporarily applied composition underlines and selection colors.
UndoCompositionAndSelectionStyles();
}
void RenderTextWin::LayoutVisualText() {
DCHECK(!runs_.empty());
if (!cached_hdc_)
cached_hdc_ = CreateCompatibleDC(NULL);
HRESULT hr = E_FAIL;
// Ensure ascent and descent are not smaller than ones of the font list.
// Keep them tall enough to draw often-used characters.
// For example, if a text field contains a Japanese character, which is
// smaller than Latin ones, and then later a Latin one is inserted, this
// ensures that the text baseline does not shift.
int ascent = font_list().GetBaseline();
int descent = font_list().GetHeight() - font_list().GetBaseline();
for (size_t i = 0; i < runs_.size(); ++i) {
internal::TextRun* run = runs_[i];
LayoutTextRun(run);
ascent = std::max(ascent, run->font.GetBaseline());
descent = std::max(descent,
run->font.GetHeight() - run->font.GetBaseline());
if (run->glyph_count > 0) {
run->advance_widths.reset(new int[run->glyph_count]);
run->offsets.reset(new GOFFSET[run->glyph_count]);
hr = ScriptPlace(cached_hdc_,
&run->script_cache,
run->glyphs.get(),
run->glyph_count,
run->visible_attributes.get(),
&(run->script_analysis),
run->advance_widths.get(),
run->offsets.get(),
&(run->abc_widths));
DCHECK(SUCCEEDED(hr));
}
}
// Build the array of bidirectional embedding levels.
scoped_ptr<BYTE[]> levels(new BYTE[runs_.size()]);
for (size_t i = 0; i < runs_.size(); ++i)
levels[i] = runs_[i]->script_analysis.s.uBidiLevel;
// Get the maps between visual and logical run indices.
visual_to_logical_.reset(new int[runs_.size()]);
logical_to_visual_.reset(new int[runs_.size()]);
hr = ScriptLayout(runs_.size(),
levels.get(),
visual_to_logical_.get(),
logical_to_visual_.get());
DCHECK(SUCCEEDED(hr));
// Precalculate run width information.
size_t preceding_run_widths = 0;
for (size_t i = 0; i < runs_.size(); ++i) {
internal::TextRun* run = runs_[visual_to_logical_[i]];
run->preceding_run_widths = preceding_run_widths;
const ABC& abc = run->abc_widths;
run->width = abc.abcA + abc.abcB + abc.abcC;
preceding_run_widths += run->width;
}
string_width_ = preceding_run_widths;
}
void RenderTextWin::LayoutTextRun(internal::TextRun* run) {
const size_t run_length = run->range.length();
const wchar_t* run_text = &(GetLayoutText()[run->range.start()]);
Font original_font = run->font;
LinkedFontsIterator fonts(original_font);
bool tried_cached_font = false;
bool tried_fallback = false;
// Keep track of the font that is able to display the greatest number of
// characters for which ScriptShape() returned S_OK. This font will be used
// in the case where no font is able to display the entire run.
int best_partial_font_missing_char_count = INT_MAX;
Font best_partial_font = original_font;
Font current_font;
run->logical_clusters.reset(new WORD[run_length]);
while (fonts.NextFont(&current_font)) {
HRESULT hr = ShapeTextRunWithFont(run, current_font);
bool glyphs_missing = false;
if (hr == USP_E_SCRIPT_NOT_IN_FONT) {
glyphs_missing = true;
} else if (hr == S_OK) {
// If |hr| is S_OK, there could still be missing glyphs in the output.
// http://msdn.microsoft.com/en-us/library/windows/desktop/dd368564.aspx
const int missing_count = CountCharsWithMissingGlyphs(run);
// Track the font that produced the least missing glyphs.
if (missing_count < best_partial_font_missing_char_count) {
best_partial_font_missing_char_count = missing_count;
best_partial_font = run->font;
}
glyphs_missing = (missing_count != 0);
} else {
NOTREACHED() << hr;
}
// Use the font if it had glyphs for all characters.
if (!glyphs_missing) {
// Save the successful fallback font that was chosen.
if (tried_fallback)
successful_substitute_fonts_[original_font.GetFontName()] = run->font;
return;
}
// First, try the cached font from previous runs, if any.
if (!tried_cached_font) {
tried_cached_font = true;
std::map<std::string, Font>::const_iterator it =
successful_substitute_fonts_.find(original_font.GetFontName());
if (it != successful_substitute_fonts_.end()) {
fonts.SetNextFont(it->second);
continue;
}
}
// If there are missing glyphs, first try finding a fallback font using a
// meta file, if it hasn't yet been attempted for this run.
// TODO(msw|asvitkine): Support RenderText's font_list()?
if (!tried_fallback) {
tried_fallback = true;
Font fallback_font;
if (ChooseFallbackFont(cached_hdc_, run->font, run_text, run_length,
&fallback_font)) {
fonts.SetNextFont(fallback_font);
continue;
}
}
}
// If a font was able to partially display the run, use that now.
if (best_partial_font_missing_char_count < static_cast<int>(run_length)) {
// Re-shape the run only if |best_partial_font| differs from the last font.
if (best_partial_font.GetNativeFont() != run->font.GetNativeFont())
ShapeTextRunWithFont(run, best_partial_font);
return;
}
// If no font was able to partially display the run, replace all glyphs
// with |wgDefault| from the original font to ensure to they don't hold
// garbage values.
// First, clear the cache and select the original font on the HDC.
ScriptFreeCache(&run->script_cache);
run->font = original_font;
SelectObject(cached_hdc_, run->font.GetNativeFont());
// Now, get the font's properties.
SCRIPT_FONTPROPERTIES properties;
memset(&properties, 0, sizeof(properties));
properties.cBytes = sizeof(properties);
HRESULT hr = ScriptGetFontProperties(cached_hdc_, &run->script_cache,
&properties);
// The initial values for the "missing" glyph and the space glyph are taken
// from the recommendations section of the OpenType spec:
// https://www.microsoft.com/typography/otspec/recom.htm
WORD missing_glyph = 0;
WORD space_glyph = 3;
if (hr == S_OK) {
missing_glyph = properties.wgDefault;
space_glyph = properties.wgBlank;
}
// Finally, initialize |glyph_count|, |glyphs|, |visible_attributes| and
// |logical_clusters| on the run (since they may not have been set yet).
run->glyph_count = run_length;
memset(run->visible_attributes.get(), 0,
run->glyph_count * sizeof(SCRIPT_VISATTR));
for (int i = 0; i < run->glyph_count; ++i)
run->glyphs[i] = IsWhitespace(run_text[i]) ? space_glyph : missing_glyph;
for (size_t i = 0; i < run_length; ++i) {
run->logical_clusters[i] = run->script_analysis.fRTL ?
run_length - 1 - i : i;
}
// TODO(msw): Don't use SCRIPT_UNDEFINED. Apparently Uniscribe can
// crash on certain surrogate pairs with SCRIPT_UNDEFINED.
// See https://bugzilla.mozilla.org/show_bug.cgi?id=341500
// And http://maxradi.us/documents/uniscribe/
run->script_analysis.eScript = SCRIPT_UNDEFINED;
}
HRESULT RenderTextWin::ShapeTextRunWithFont(internal::TextRun* run,
const Font& font) {
// Update the run's font only if necessary. If the two fonts wrap the same
// PlatformFontWin object, their native fonts will have the same value.
if (run->font.GetNativeFont() != font.GetNativeFont()) {
const int font_size = run->font.GetFontSize();
const int font_height = run->font.GetHeight();
run->font = font;
DeriveFontIfNecessary(font_size, font_height, run->font_style, &run->font);
ScriptFreeCache(&run->script_cache);
}
// Select the font desired for glyph generation.
SelectObject(cached_hdc_, run->font.GetNativeFont());
HRESULT hr = E_OUTOFMEMORY;
const size_t run_length = run->range.length();
const wchar_t* run_text = &(GetLayoutText()[run->range.start()]);
// Guess the expected number of glyphs from the length of the run.
// MSDN suggests this at http://msdn.microsoft.com/en-us/library/dd368564.aspx
size_t max_glyphs = static_cast<size_t>(1.5 * run_length + 16);
while (hr == E_OUTOFMEMORY && max_glyphs <= kMaxGlyphs) {
run->glyph_count = 0;
run->glyphs.reset(new WORD[max_glyphs]);
run->visible_attributes.reset(new SCRIPT_VISATTR[max_glyphs]);
hr = ScriptShape(cached_hdc_, &run->script_cache, run_text, run_length,
max_glyphs, &run->script_analysis, run->glyphs.get(),
run->logical_clusters.get(), run->visible_attributes.get(),
&run->glyph_count);
// Ensure that |kMaxGlyphs| is attempted and the loop terminates afterward.
max_glyphs = std::max(max_glyphs + 1, std::min(max_glyphs * 2, kMaxGlyphs));
}
return hr;
}
int RenderTextWin::CountCharsWithMissingGlyphs(internal::TextRun* run) const {
int chars_not_missing_glyphs = 0;
SCRIPT_FONTPROPERTIES properties;
memset(&properties, 0, sizeof(properties));
properties.cBytes = sizeof(properties);
ScriptGetFontProperties(cached_hdc_, &run->script_cache, &properties);
const wchar_t* run_text = &(GetLayoutText()[run->range.start()]);
for (size_t char_index = 0; char_index < run->range.length(); ++char_index) {
const int glyph_index = run->logical_clusters[char_index];
DCHECK_GE(glyph_index, 0);
DCHECK_LT(glyph_index, run->glyph_count);
if (run->glyphs[glyph_index] == properties.wgDefault)
continue;
// Windows Vista sometimes returns glyphs equal to wgBlank (instead of
// wgDefault), with fZeroWidth set. Treat such cases as having missing
// glyphs if the corresponding character is not whitespace.
// See: http://crbug.com/125629
if (run->glyphs[glyph_index] == properties.wgBlank &&
run->visible_attributes[glyph_index].fZeroWidth &&
!IsWhitespace(run_text[char_index]) &&
!IsUnicodeBidiControlCharacter(run_text[char_index])) {
continue;
}
++chars_not_missing_glyphs;
}
DCHECK_LE(chars_not_missing_glyphs, static_cast<int>(run->range.length()));
return run->range.length() - chars_not_missing_glyphs;
}
size_t RenderTextWin::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 RenderTextWin::GetRunContainingXCoord(int x) const {
DCHECK(!needs_layout_);
// Find the text run containing the argument point (assumed already offset).
for (size_t run = 0; run < runs_.size(); ++run) {
if ((runs_[run]->preceding_run_widths <= x) &&
((runs_[run]->preceding_run_widths + runs_[run]->width) > x))
return run;
}
return runs_.size();
}
SelectionModel RenderTextWin::FirstSelectionModelInsideRun(
const internal::TextRun* run) {
size_t position = LayoutIndexToTextIndex(run->range.start());
position = IndexOfAdjacentGrapheme(position, CURSOR_FORWARD);
return SelectionModel(position, CURSOR_BACKWARD);
}
SelectionModel RenderTextWin::LastSelectionModelInsideRun(
const internal::TextRun* run) {
size_t position = LayoutIndexToTextIndex(run->range.end());
position = IndexOfAdjacentGrapheme(position, CURSOR_BACKWARD);
return SelectionModel(position, CURSOR_FORWARD);
}
RenderText* RenderText::CreateInstance() {
return new RenderTextWin;
}
} // namespace gfx