MinikinUtils.cpp revision 805f6ebf17e2791624bb1a30834b4c1cc65583bf 
1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#define LOG_TAG "Minikin"
18#include <cutils/log.h>
19#include <string>
20
21#include "SkPathMeasure.h"
22#include "Paint.h"
23#include "TypefaceImpl.h"
24
25#include "MinikinUtils.h"
26
27namespace android {
28
29// Do an sprintf starting at offset n, abort on overflow
30static int snprintfcat(char* buf, int off, int size, const char* format, ...)
31        __attribute__((__format__(__printf__, 4, 5)));
32static int snprintfcat(char* buf, int off, int size, const char* format, ...) {
33    va_list args;
34    va_start(args, format);
35    int n = vsnprintf(buf + off, size - off, format, args);
36    LOG_ALWAYS_FATAL_IF(n >= size - off, "String overflow in setting layout properties");
37    va_end(args);
38    return off + n;
39}
40
41void MinikinUtils::doLayout(Layout* layout, const Paint* paint, int bidiFlags, TypefaceImpl* typeface,
42        const uint16_t* buf, size_t start, size_t count, size_t bufSize) {
43    TypefaceImpl* resolvedFace = TypefaceImpl_resolveDefault(typeface);
44    layout->setFontCollection(resolvedFace->fFontCollection);
45    FontStyle resolved = resolvedFace->fStyle;
46
47    /* Prepare minikin FontStyle */
48    SkString langStr = paint->getPaintOptionsAndroid().getLanguage().getTag();
49    FontLanguage minikinLang(langStr.c_str(), langStr.size());
50    SkPaintOptionsAndroid::FontVariant var = paint->getPaintOptionsAndroid().getFontVariant();
51    FontVariant minikinVariant = var == SkPaintOptionsAndroid::kElegant_Variant ? VARIANT_ELEGANT
52            : VARIANT_COMPACT;
53    FontStyle minikinStyle(minikinLang, minikinVariant, resolved.getWeight(), resolved.getItalic());
54
55    /* Prepare minikin Paint */
56    MinikinPaint minikinPaint;
57    minikinPaint.size = (int)/*WHY?!*/paint->getTextSize();
58    minikinPaint.scaleX = paint->getTextScaleX();
59    minikinPaint.skewX = paint->getTextSkewX();
60    minikinPaint.letterSpacing = paint->getLetterSpacing();
61    minikinPaint.paintFlags = MinikinFontSkia::packPaintFlags(paint);
62    minikinPaint.fontFeatureSettings = paint->getFontFeatureSettings();
63
64    layout->doLayout(buf, start, count, bufSize, bidiFlags, minikinStyle, minikinPaint);
65}
66
67float MinikinUtils::xOffsetForTextAlign(Paint* paint, const Layout& layout) {
68    switch (paint->getTextAlign()) {
69        case Paint::kCenter_Align:
70            return layout.getAdvance() * -0.5f;
71            break;
72        case Paint::kRight_Align:
73            return -layout.getAdvance();
74            break;
75        default:
76            break;
77    }
78    return 0;
79}
80
81float MinikinUtils::hOffsetForTextAlign(Paint* paint, const Layout& layout, const SkPath& path) {
82    float align = 0;
83    switch (paint->getTextAlign()) {
84        case Paint::kCenter_Align:
85            align = -0.5f;
86            break;
87        case Paint::kRight_Align:
88            align = -1;
89            break;
90        default:
91            return 0;
92    }
93    SkPathMeasure measure(path, false);
94    return align * (layout.getAdvance() - measure.getLength());
95}
96
97}
98