1/*
2 * Copyright 2018 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef SkFontPriv_DEFINED
9#define SkFontPriv_DEFINED
10
11#include "include/core/SkFont.h"
12#include "include/core/SkMatrix.h"
13#include "include/core/SkTypeface.h"
14
15class SkReadBuffer;
16class SkWriteBuffer;
17
18class SkFontPriv {
19public:
20 /* This is the size we use when we ask for a glyph's path. We then
21 * post-transform it as we draw to match the request.
22 * This is done to try to re-use cache entries for the path.
23 *
24 * This value is somewhat arbitrary. In theory, it could be 1, since
25 * we store paths as floats. However, we get the path from the font
26 * scaler, and it may represent its paths as fixed-point (or 26.6),
27 * so we shouldn't ask for something too big (might overflow 16.16)
28 * or too small (underflow 26.6).
29 *
30 * This value could track kMaxSizeForGlyphCache, assuming the above
31 * constraints, but since we ask for unhinted paths, the two values
32 * need not match per-se.
33 */
34 static constexpr int kCanonicalTextSizeForPaths = 64;
35
36 /**
37 * Return a matrix that applies the paint's text values: size, scale, skew
38 */
39 static SkMatrix MakeTextMatrix(SkScalar size, SkScalar scaleX, SkScalar skewX) {
40 SkMatrix m = SkMatrix::MakeScale(size * scaleX, size);
41 if (skewX) {
42 m.postSkew(skewX, 0);
43 }
44 return m;
45 }
46
47 static SkMatrix MakeTextMatrix(const SkFont& font) {
48 return MakeTextMatrix(font.getSize(), font.getScaleX(), font.getSkewX());
49 }
50
51 static void ScaleFontMetrics(SkFontMetrics*, SkScalar);
52
53 /**
54 Returns the union of bounds of all glyphs.
55 Returned dimensions are computed by font manager from font data,
56 ignoring SkPaint::Hinting. Includes font metrics, but not fake bold or SkPathEffect.
57
58 If text size is large, text scale is one, and text skew is zero,
59 returns the bounds as:
60 { SkFontMetrics::fXMin, SkFontMetrics::fTop, SkFontMetrics::fXMax, SkFontMetrics::fBottom }.
61
62 @return union of bounds of all glyphs
63 */
64 static SkRect GetFontBounds(const SkFont&);
65
66 static bool IsFinite(const SkFont& font) {
67 return SkScalarIsFinite(font.getSize()) &&
68 SkScalarIsFinite(font.getScaleX()) &&
69 SkScalarIsFinite(font.getSkewX());
70 }
71
72 // Returns the number of elements (characters or glyphs) in the array.
73 static int CountTextElements(const void* text, size_t byteLength, SkTextEncoding);
74
75 static void GlyphsToUnichars(const SkFont&, const uint16_t glyphs[], int count, SkUnichar[]);
76
77 static void Flatten(const SkFont&, SkWriteBuffer& buffer);
78 static bool Unflatten(SkFont*, SkReadBuffer& buffer);
79
80 static inline uint8_t Flags(const SkFont& font) { return font.fFlags; }
81};
82
83class SkAutoToGlyphs {
84public:
85 SkAutoToGlyphs(const SkFont& font, const void* text, size_t length, SkTextEncoding encoding) {
86 if (encoding == SkTextEncoding::kGlyphID || length == 0) {
87 fGlyphs = reinterpret_cast<const uint16_t*>(text);
88 fCount = length >> 1;
89 } else {
90 fCount = font.countText(text, length, encoding);
91 if (fCount < 0) {
92 fCount = 0;
93 }
94 fStorage.reset(fCount);
95 font.textToGlyphs(text, length, encoding, fStorage.get(), fCount);
96 fGlyphs = fStorage.get();
97 }
98 }
99
100 int count() const { return fCount; }
101 const uint16_t* glyphs() const { return fGlyphs; }
102
103private:
104 SkAutoSTArray<32, uint16_t> fStorage;
105 const uint16_t* fGlyphs;
106 int fCount;
107};
108
109#endif
110