1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
|
// Copyright 2015 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.
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_FONT_FALLBACK_ITERATOR_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_FONT_FALLBACK_ITERATOR_H_
#include "base/memory/scoped_refptr.h"
#include "third_party/blink/renderer/platform/fonts/font_data_for_range_set.h"
#include "third_party/blink/renderer/platform/fonts/font_fallback_priority.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/hash_map.h"
#include "third_party/blink/renderer/platform/wtf/ref_counted.h"
#include "third_party/blink/renderer/platform/wtf/text/wtf_uchar.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"
namespace blink {
class FontDescription;
class FontFallbackList;
class SimpleFontData;
class FontFallbackIterator {
STACK_ALLOCATED();
public:
FontFallbackIterator(const FontDescription&,
scoped_refptr<FontFallbackList>,
FontFallbackPriority);
FontFallbackIterator(FontFallbackIterator&&) = default;
FontFallbackIterator(const FontFallbackIterator&) = delete;
FontFallbackIterator& operator=(const FontFallbackIterator&) = delete;
bool HasNext() const { return fallback_stage_ != kOutOfLuck; }
// Returns whether the next call to Next() needs a full hint list, or whether
// a single character is sufficient. Intended to serve as an optimization in
// HarfBuzzShaper to avoid spending too much time and resources collecting a
// full hint character list. Returns true when the next font in line is a
// segmented font, i.e. one that requires the hint list to work out which
// unicode range segment should be used.
bool NeedsHintList() const;
// Some system fallback APIs (Windows, Android) require a character, or a
// portion of the string to be passed. On Mac and Linux, we get a list of
// fonts without passing in characters.
scoped_refptr<FontDataForRangeSet> Next(const Vector<UChar32>& hint_list);
private:
bool RangeSetContributesForHint(const Vector<UChar32>& hint_list,
const FontDataForRangeSet*);
bool AlreadyLoadingRangeForHintChar(UChar32 hint_char);
void WillUseRange(const AtomicString& family, const FontDataForRangeSet&);
scoped_refptr<FontDataForRangeSet> UniqueOrNext(
scoped_refptr<FontDataForRangeSet> candidate,
const Vector<UChar32>& hint_list);
scoped_refptr<SimpleFontData> FallbackPriorityFont(UChar32 hint);
scoped_refptr<SimpleFontData> UniqueSystemFontForHintList(
const Vector<UChar32>& hint_list);
const FontDescription& font_description_;
scoped_refptr<FontFallbackList> font_fallback_list_;
int current_font_data_index_;
unsigned segmented_face_index_;
enum FallbackStage {
kFallbackPriorityFonts,
kFontGroupFonts,
kSegmentedFace,
kPreferencesFonts,
kSystemFonts,
kFirstCandidateForNotdefGlyph,
kOutOfLuck
};
FallbackStage fallback_stage_;
HashSet<UChar32> previously_asked_for_hint_;
// FontFallbackIterator is meant for single use by HarfBuzzShaper,
// traversing through the fonts for shaping only once. We must not return
// duplicate FontDataForRangeSet objects from the Next() iteration function
// as returning a duplicate value causes a shaping run that won't return any
// results. The exception is that if all fonts fail, we return the first
// candidate to be used for rendering the .notdef glyph, and set HasNext() to
// false.
HashSet<uint32_t> unique_font_data_for_range_sets_returned_;
scoped_refptr<FontDataForRangeSet> first_candidate_;
Vector<scoped_refptr<FontDataForRangeSet>> tracked_loading_range_sets_;
FontFallbackPriority font_fallback_priority_;
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_FONTS_FONT_FALLBACK_ITERATOR_H_
|
