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 <SkFontHost.h>
37 #include <SkPaint.h>
38 #include <SkPath.h>
39 #include <SkPoint.h>
40 #include <SkRect.h>
41 #include <SkUtils.h>
42
43 #include <hb.h>
44
45 namespace android {
46
47 // Our implementation of the callbacks which Harfbuzz requires by using Skia
48 // calls. See the Harfbuzz source for references about what these callbacks do.
49
50 struct HarfBuzzFontData {
HarfBuzzFontDataandroid::HarfBuzzFontData51 HarfBuzzFontData(SkPaint* paint) : m_paint(paint) { }
52 SkPaint* m_paint;
53 };
54
SkiaGetGlyphWidthAndExtents(SkPaint * paint,hb_codepoint_t codepoint,hb_position_t * width,hb_glyph_extents_t * extents)55 static void SkiaGetGlyphWidthAndExtents(SkPaint* paint, hb_codepoint_t codepoint, hb_position_t* width, hb_glyph_extents_t* extents)
56 {
57 ALOG_ASSERT(codepoint <= 0xFFFF);
58 paint->setTextEncoding(SkPaint::kGlyphID_TextEncoding);
59
60 SkScalar skWidth;
61 SkRect skBounds;
62 uint16_t glyph = codepoint;
63
64 paint->getTextWidths(&glyph, sizeof(glyph), &skWidth, &skBounds);
65 #if DEBUG_GLYPHS
66 ALOGD("returned glyph for %i: width = %f", codepoint, skWidth);
67 #endif
68 if (width)
69 *width = SkScalarToHBFixed(skWidth);
70 if (extents) {
71 // Invert y-axis because Skia is y-grows-down but we set up harfbuzz to be y-grows-up.
72 extents->x_bearing = SkScalarToHBFixed(skBounds.fLeft);
73 extents->y_bearing = SkScalarToHBFixed(-skBounds.fTop);
74 extents->width = SkScalarToHBFixed(skBounds.width());
75 extents->height = SkScalarToHBFixed(-skBounds.height());
76 }
77 }
78
harfbuzzGetGlyph(hb_font_t * hbFont,void * fontData,hb_codepoint_t unicode,hb_codepoint_t variationSelector,hb_codepoint_t * glyph,void * userData)79 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)
80 {
81 HarfBuzzFontData* hbFontData = reinterpret_cast<HarfBuzzFontData*>(fontData);
82
83 if (unicode > 0x10ffff) {
84 unicode = 0xfffd;
85 }
86 SkPaint* paint = hbFontData->m_paint;
87 // It would be better to use kUTF32_TextEncoding directly
88 paint->setTextEncoding(SkPaint::kUTF16_TextEncoding);
89 uint16_t glyph16;
90 uint16_t unichar[2];
91 size_t size = SkUTF16_FromUnichar(unicode, unichar);
92 paint->textToGlyphs(unichar, size * sizeof(*unichar), &glyph16);
93 *glyph = glyph16;
94 return !!*glyph;
95 }
96
harfbuzzGetGlyphHorizontalAdvance(hb_font_t * hbFont,void * fontData,hb_codepoint_t glyph,void * userData)97 static hb_position_t harfbuzzGetGlyphHorizontalAdvance(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, void* userData)
98 {
99 HarfBuzzFontData* hbFontData = reinterpret_cast<HarfBuzzFontData*>(fontData);
100 hb_position_t advance = 0;
101
102 SkiaGetGlyphWidthAndExtents(hbFontData->m_paint, glyph, &advance, 0);
103 return advance;
104 }
105
harfbuzzGetGlyphHorizontalOrigin(hb_font_t * hbFont,void * fontData,hb_codepoint_t glyph,hb_position_t * x,hb_position_t * y,void * userData)106 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)
107 {
108 // Just return true, following the way that Harfbuzz-FreeType
109 // implementation does.
110 return true;
111 }
112
harfbuzzGetGlyphExtents(hb_font_t * hbFont,void * fontData,hb_codepoint_t glyph,hb_glyph_extents_t * extents,void * userData)113 static hb_bool_t harfbuzzGetGlyphExtents(hb_font_t* hbFont, void* fontData, hb_codepoint_t glyph, hb_glyph_extents_t* extents, void* userData)
114 {
115 HarfBuzzFontData* hbFontData = reinterpret_cast<HarfBuzzFontData*>(fontData);
116
117 SkiaGetGlyphWidthAndExtents(hbFontData->m_paint, glyph, 0, extents);
118 return true;
119 }
120
harfbuzzSkiaGetFontFuncs()121 static hb_font_funcs_t* harfbuzzSkiaGetFontFuncs()
122 {
123 static hb_font_funcs_t* harfbuzzSkiaFontFuncs = 0;
124
125 // We don't set callback functions which we can't support.
126 // Harfbuzz will use the fallback implementation if they aren't set.
127 if (!harfbuzzSkiaFontFuncs) {
128 harfbuzzSkiaFontFuncs = hb_font_funcs_create();
129 hb_font_funcs_set_glyph_func(harfbuzzSkiaFontFuncs, harfbuzzGetGlyph, 0, 0);
130 hb_font_funcs_set_glyph_h_advance_func(harfbuzzSkiaFontFuncs, harfbuzzGetGlyphHorizontalAdvance, 0, 0);
131 hb_font_funcs_set_glyph_h_origin_func(harfbuzzSkiaFontFuncs, harfbuzzGetGlyphHorizontalOrigin, 0, 0);
132 hb_font_funcs_set_glyph_extents_func(harfbuzzSkiaFontFuncs, harfbuzzGetGlyphExtents, 0, 0);
133 hb_font_funcs_make_immutable(harfbuzzSkiaFontFuncs);
134 }
135 return harfbuzzSkiaFontFuncs;
136 }
137
harfbuzzSkiaReferenceTable(hb_face_t * face,hb_tag_t tag,void * userData)138 hb_blob_t* harfbuzzSkiaReferenceTable(hb_face_t* face, hb_tag_t tag, void* userData)
139 {
140 SkTypeface* typeface = reinterpret_cast<SkTypeface*>(userData);
141
142 const size_t tableSize = typeface->getTableSize(tag);
143 if (!tableSize)
144 return 0;
145
146 char* buffer = reinterpret_cast<char*>(malloc(tableSize));
147 if (!buffer)
148 return 0;
149 size_t actualSize = typeface->getTableData(tag, 0, tableSize, buffer);
150 if (tableSize != actualSize) {
151 free(buffer);
152 return 0;
153 }
154
155 return hb_blob_create(const_cast<char*>(buffer), tableSize,
156 HB_MEMORY_MODE_WRITABLE, buffer, free);
157 }
158
destroyHarfBuzzFontData(void * data)159 static void destroyHarfBuzzFontData(void* data) {
160 delete (HarfBuzzFontData*)data;
161 }
162
createFont(hb_face_t * face,SkPaint * paint,float sizeX,float sizeY)163 hb_font_t* createFont(hb_face_t* face, SkPaint* paint, float sizeX, float sizeY) {
164 hb_font_t* font = hb_font_create(face);
165
166 // Note: this needs to be reworked when we do subpixels
167 int x_ppem = floor(sizeX + 0.5);
168 int y_ppem = floor(sizeY + 0.5);
169 hb_font_set_ppem(font, x_ppem, y_ppem);
170 hb_font_set_scale(font, HBFloatToFixed(sizeX), HBFloatToFixed(sizeY));
171
172 HarfBuzzFontData* data = new HarfBuzzFontData(paint);
173 hb_font_set_funcs(font, harfbuzzSkiaGetFontFuncs(), data, destroyHarfBuzzFontData);
174
175 return font;
176 }
177
178 } // namespace android
179