1 /*
2 * Copyright (c) 2012 Google Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
6 * met:
7 *
8 * * Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * * Redistributions in binary form must reproduce the above
11 * copyright notice, this list of conditions and the following disclaimer
12 * in the documentation and/or other materials provided with the
13 * distribution.
14 * * Neither the name of Google Inc. nor the names of its
15 * contributors may be used to endorse or promote products derived from
16 * this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31 #define LOG_TAG "TextLayoutCache"
32
33 #include "HarfBuzzNGFaceSkia.h"
34
35 #include <cutils/log.h>
36 #include <SkPaint.h>
37 #include <SkPath.h>
38 #include <SkPoint.h>
39 #include <SkRect.h>
40 #include <SkTypeface.h>
41 #include <SkUtils.h>
42
43 #include <hb.h>
44
45 namespace android {
46
47 static const bool kDebugGlyphs = false;
48
49 // Our implementation of the callbacks which Harfbuzz requires by using Skia
50 // calls. See the Harfbuzz source for references about what these callbacks do.
51
52 struct HarfBuzzFontData {
HarfBuzzFontDataandroid::HarfBuzzFontData53 HarfBuzzFontData(SkPaint* paint) : m_paint(paint) { }
54 SkPaint* m_paint;
55 };
56
SkiaGetGlyphWidthAndExtents(SkPaint * paint,hb_codepoint_t codepoint,hb_position_t * width,hb_glyph_extents_t * extents)57 static void SkiaGetGlyphWidthAndExtents(SkPaint* paint, hb_codepoint_t codepoint, hb_position_t* width, hb_glyph_extents_t* extents)
58 {
59 ALOG_ASSERT(codepoint <= 0xFFFF);
60 paint->setTextEncoding(SkPaint::kGlyphID_TextEncoding);
61
62 SkScalar skWidth;
63 SkRect skBounds;
64 uint16_t glyph = codepoint;
65
66 paint->getTextWidths(&glyph, sizeof(glyph), &skWidth, &skBounds);
67 if (kDebugGlyphs) {
68 ALOGD("returned glyph for %i: width = %f", codepoint, skWidth);
69 }
70 if (width)
71 *width = SkScalarToHBFixed(skWidth);
72 if (extents) {
73 // Invert y-axis because Skia is y-grows-down but we set up harfbuzz to be y-grows-up.
74 extents->x_bearing = SkScalarToHBFixed(skBounds.fLeft);
75 extents->y_bearing = SkScalarToHBFixed(-skBounds.fTop);
76 extents->width = SkScalarToHBFixed(skBounds.width());
77 extents->height = SkScalarToHBFixed(-skBounds.height());
78 }
79 }
80
harfbuzzGetGlyph(hb_font_t * hbFont,void * fontData,hb_codepoint_t unicode,hb_codepoint_t variationSelector,hb_codepoint_t * glyph,void * userData)81 static hb_bool_t harfbuzzGetGlyph(hb_font_t* hbFont, void* fontData, hb_codepoint_t unicode, hb_codepoint_t variationSelector, hb_codepoint_t* glyph, void* userData)
82 {
83 HarfBuzzFontData* hbFontData = reinterpret_cast<HarfBuzzFontData*>(fontData);
84
85 if (unicode > 0x10ffff) {
86 unicode = 0xfffd;
87 }
88 SkPaint* paint = hbFontData->m_paint;
89 // It would be better to use kUTF32_TextEncoding directly
90 paint->setTextEncoding(SkPaint::kUTF16_TextEncoding);
91 uint16_t glyph16;
92 uint16_t unichar[2];
93 size_t size = SkUTF16_FromUnichar(unicode, unichar);
94 paint->textToGlyphs(unichar, size * sizeof(*unichar), &glyph16);
95 *glyph = glyph16;
96 return !!*glyph;
97 }
98
harfbuzzGetGlyphHorizontalAdvance(hb_font_t * hbFont,void * fontData,hb_codepoint_t glyph,void * userData)99 static hb_position_t harfbuzzGetGlyphHorizontalAdvance(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, void* userData)
100 {
101 HarfBuzzFontData* hbFontData = reinterpret_cast<HarfBuzzFontData*>(fontData);
102 hb_position_t advance = 0;
103
104 SkiaGetGlyphWidthAndExtents(hbFontData->m_paint, glyph, &advance, 0);
105 return advance;
106 }
107
harfbuzzGetGlyphHorizontalOrigin(hb_font_t * hbFont,void * fontData,hb_codepoint_t glyph,hb_position_t * x,hb_position_t * y,void * userData)108 static hb_bool_t harfbuzzGetGlyphHorizontalOrigin(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, hb_position_t* x, hb_position_t* y, void* userData)
109 {
110 // Just return true, following the way that Harfbuzz-FreeType
111 // implementation does.
112 return true;
113 }
114
harfbuzzGetGlyphExtents(hb_font_t * hbFont,void * fontData,hb_codepoint_t glyph,hb_glyph_extents_t * extents,void * userData)115 static hb_bool_t harfbuzzGetGlyphExtents(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, hb_glyph_extents_t* extents, void* userData)
116 {
117 HarfBuzzFontData* hbFontData = reinterpret_cast<HarfBuzzFontData*>(fontData);
118
119 SkiaGetGlyphWidthAndExtents(hbFontData->m_paint, glyph, 0, extents);
120 return true;
121 }
122
harfbuzzSkiaGetFontFuncs()123 static hb_font_funcs_t* harfbuzzSkiaGetFontFuncs()
124 {
125 static hb_font_funcs_t* harfbuzzSkiaFontFuncs = 0;
126
127 // We don't set callback functions which we can't support.
128 // Harfbuzz will use the fallback implementation if they aren't set.
129 if (!harfbuzzSkiaFontFuncs) {
130 harfbuzzSkiaFontFuncs = hb_font_funcs_create();
131 hb_font_funcs_set_glyph_func(harfbuzzSkiaFontFuncs, harfbuzzGetGlyph, 0, 0);
132 hb_font_funcs_set_glyph_h_advance_func(harfbuzzSkiaFontFuncs, harfbuzzGetGlyphHorizontalAdvance, 0, 0);
133 hb_font_funcs_set_glyph_h_origin_func(harfbuzzSkiaFontFuncs, harfbuzzGetGlyphHorizontalOrigin, 0, 0);
134 hb_font_funcs_set_glyph_extents_func(harfbuzzSkiaFontFuncs, harfbuzzGetGlyphExtents, 0, 0);
135 hb_font_funcs_make_immutable(harfbuzzSkiaFontFuncs);
136 }
137 return harfbuzzSkiaFontFuncs;
138 }
139
harfbuzzSkiaReferenceTable(hb_face_t * face,hb_tag_t tag,void * userData)140 hb_blob_t* harfbuzzSkiaReferenceTable(hb_face_t* face, hb_tag_t tag, void* userData)
141 {
142 SkTypeface* typeface = reinterpret_cast<SkTypeface*>(userData);
143
144 const size_t tableSize = typeface->getTableSize(tag);
145 if (!tableSize)
146 return 0;
147
148 char* buffer = reinterpret_cast<char*>(malloc(tableSize));
149 if (!buffer)
150 return 0;
151 size_t actualSize = typeface->getTableData(tag, 0, tableSize, buffer);
152 if (tableSize != actualSize) {
153 free(buffer);
154 return 0;
155 }
156
157 return hb_blob_create(const_cast<char*>(buffer), tableSize,
158 HB_MEMORY_MODE_WRITABLE, buffer, free);
159 }
160
destroyHarfBuzzFontData(void * data)161 static void destroyHarfBuzzFontData(void* data) {
162 delete (HarfBuzzFontData*)data;
163 }
164
createFont(hb_face_t * face,SkPaint * paint,float sizeX,float sizeY)165 hb_font_t* createFont(hb_face_t* face, SkPaint* paint, float sizeX, float sizeY) {
166 hb_font_t* font = hb_font_create(face);
167
168 // Note: this needs to be reworked when we do subpixels
169 int x_ppem = floor(sizeX + 0.5);
170 int y_ppem = floor(sizeY + 0.5);
171 hb_font_set_ppem(font, x_ppem, y_ppem);
172 hb_font_set_scale(font, HBFloatToFixed(sizeX), HBFloatToFixed(sizeY));
173
174 HarfBuzzFontData* data = new HarfBuzzFontData(paint);
175 hb_font_set_funcs(font, harfbuzzSkiaGetFontFuncs(), data, destroyHarfBuzzFontData);
176
177 return font;
178 }
179
180 } // namespace android
181