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 <stdlib.h>
36
37 #include <log/log.h>
38
39 #include <SkPaint.h>
40 #include <SkPath.h>
41 #include <SkPoint.h>
42 #include <SkRect.h>
43 #include <SkTypeface.h>
44
45 #include <hb.h>
46
47 namespace android {
48
49 static const bool kDebugGlyphs = false;
50
51 // Our implementation of the callbacks which Harfbuzz requires by using Skia
52 // calls. See the Harfbuzz source for references about what these callbacks do.
53
54 struct HarfBuzzFontData {
HarfBuzzFontDataandroid::HarfBuzzFontData55 explicit HarfBuzzFontData(SkPaint* paint) : m_paint(paint) { }
56 SkPaint* m_paint;
57 };
58
SkiaGetGlyphWidthAndExtents(SkPaint * paint,hb_codepoint_t codepoint,hb_position_t * width,hb_glyph_extents_t * extents)59 static void SkiaGetGlyphWidthAndExtents(SkPaint* paint, hb_codepoint_t codepoint, hb_position_t* width, hb_glyph_extents_t* extents)
60 {
61 ALOG_ASSERT(codepoint <= 0xFFFF);
62 paint->setTextEncoding(SkPaint::kGlyphID_TextEncoding);
63
64 SkScalar skWidth;
65 SkRect skBounds;
66 uint16_t glyph = codepoint;
67
68 paint->getTextWidths(&glyph, sizeof(glyph), &skWidth, &skBounds);
69 if (kDebugGlyphs) {
70 ALOGD("returned glyph for %i: width = %f", codepoint, skWidth);
71 }
72 if (width)
73 *width = SkScalarToHBFixed(skWidth);
74 if (extents) {
75 // Invert y-axis because Skia is y-grows-down but we set up harfbuzz to be y-grows-up.
76 extents->x_bearing = SkScalarToHBFixed(skBounds.fLeft);
77 extents->y_bearing = SkScalarToHBFixed(-skBounds.fTop);
78 extents->width = SkScalarToHBFixed(skBounds.width());
79 extents->height = SkScalarToHBFixed(-skBounds.height());
80 }
81 }
82
harfbuzzGetGlyph(hb_font_t * hbFont,void * fontData,hb_codepoint_t unicode,hb_codepoint_t variationSelector,hb_codepoint_t * glyph,void * userData)83 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)
84 {
85 HarfBuzzFontData* hbFontData = reinterpret_cast<HarfBuzzFontData*>(fontData);
86 SkPaint* paint = hbFontData->m_paint;
87 paint->setTextEncoding(SkPaint::kUTF32_TextEncoding);
88
89 if (unicode > 0x10ffff) {
90 unicode = 0xfffd;
91 }
92 SkUnichar unichar = unicode;
93
94 uint16_t glyph16;
95 paint->textToGlyphs(&unichar, sizeof(unichar), &glyph16);
96 *glyph = glyph16;
97 return !!*glyph;
98 }
99
harfbuzzGetGlyphHorizontalAdvance(hb_font_t * hbFont,void * fontData,hb_codepoint_t glyph,void * userData)100 static hb_position_t harfbuzzGetGlyphHorizontalAdvance(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, void* userData)
101 {
102 HarfBuzzFontData* hbFontData = reinterpret_cast<HarfBuzzFontData*>(fontData);
103 hb_position_t advance = 0;
104
105 SkiaGetGlyphWidthAndExtents(hbFontData->m_paint, glyph, &advance, 0);
106 return advance;
107 }
108
harfbuzzGetGlyphHorizontalOrigin(hb_font_t * hbFont,void * fontData,hb_codepoint_t glyph,hb_position_t * x,hb_position_t * y,void * userData)109 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)
110 {
111 // Just return true, following the way that Harfbuzz-FreeType
112 // implementation does.
113 return true;
114 }
115
harfbuzzGetGlyphExtents(hb_font_t * hbFont,void * fontData,hb_codepoint_t glyph,hb_glyph_extents_t * extents,void * userData)116 static hb_bool_t harfbuzzGetGlyphExtents(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, hb_glyph_extents_t* extents, void* userData)
117 {
118 HarfBuzzFontData* hbFontData = reinterpret_cast<HarfBuzzFontData*>(fontData);
119
120 SkiaGetGlyphWidthAndExtents(hbFontData->m_paint, glyph, 0, extents);
121 return true;
122 }
123
harfbuzzSkiaGetFontFuncs()124 static hb_font_funcs_t* harfbuzzSkiaGetFontFuncs()
125 {
126 static hb_font_funcs_t* harfbuzzSkiaFontFuncs = 0;
127
128 // We don't set callback functions which we can't support.
129 // Harfbuzz will use the fallback implementation if they aren't set.
130 if (!harfbuzzSkiaFontFuncs) {
131 harfbuzzSkiaFontFuncs = hb_font_funcs_create();
132 hb_font_funcs_set_glyph_func(harfbuzzSkiaFontFuncs, harfbuzzGetGlyph, 0, 0);
133 hb_font_funcs_set_glyph_h_advance_func(harfbuzzSkiaFontFuncs, harfbuzzGetGlyphHorizontalAdvance, 0, 0);
134 hb_font_funcs_set_glyph_h_origin_func(harfbuzzSkiaFontFuncs, harfbuzzGetGlyphHorizontalOrigin, 0, 0);
135 hb_font_funcs_set_glyph_extents_func(harfbuzzSkiaFontFuncs, harfbuzzGetGlyphExtents, 0, 0);
136 hb_font_funcs_make_immutable(harfbuzzSkiaFontFuncs);
137 }
138 return harfbuzzSkiaFontFuncs;
139 }
140
harfbuzzSkiaReferenceTable(hb_face_t * face,hb_tag_t tag,void * userData)141 hb_blob_t* harfbuzzSkiaReferenceTable(hb_face_t* face, hb_tag_t tag, void* userData)
142 {
143 SkTypeface* typeface = reinterpret_cast<SkTypeface*>(userData);
144
145 const size_t tableSize = typeface->getTableSize(tag);
146 if (!tableSize)
147 return 0;
148
149 char* buffer = reinterpret_cast<char*>(malloc(tableSize));
150 if (!buffer)
151 return 0;
152 size_t actualSize = typeface->getTableData(tag, 0, tableSize, buffer);
153 if (tableSize != actualSize) {
154 free(buffer);
155 return 0;
156 }
157
158 return hb_blob_create(const_cast<char*>(buffer), tableSize,
159 HB_MEMORY_MODE_WRITABLE, buffer, free);
160 }
161
destroyHarfBuzzFontData(void * data)162 static void destroyHarfBuzzFontData(void* data) {
163 delete (HarfBuzzFontData*)data;
164 }
165
createFont(hb_face_t * face,SkPaint * paint,float sizeX,float sizeY)166 hb_font_t* createFont(hb_face_t* face, SkPaint* paint, float sizeX, float sizeY) {
167 hb_font_t* font = hb_font_create(face);
168
169 // Note: this needs to be reworked when we do subpixels
170 int x_ppem = floor(sizeX + 0.5);
171 int y_ppem = floor(sizeY + 0.5);
172 hb_font_set_ppem(font, x_ppem, y_ppem);
173 hb_font_set_scale(font, HBFloatToFixed(sizeX), HBFloatToFixed(sizeY));
174
175 HarfBuzzFontData* data = new HarfBuzzFontData(paint);
176 hb_font_set_funcs(font, harfbuzzSkiaGetFontFuncs(), data, destroyHarfBuzzFontData);
177
178 return font;
179 }
180
181 } // namespace android
182