1 /*
2 * Copyright 2016 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 #include "SkShaper.h"
8 #include "SkStream.h"
9 #include "SkTextBlob.h"
10 #include "SkTypeface.h"
11
12 struct SkShaper::Impl {
13 sk_sp<SkTypeface> fTypeface;
14 };
15
SkShaper(sk_sp<SkTypeface> tf)16 SkShaper::SkShaper(sk_sp<SkTypeface> tf) : fImpl(new Impl) {
17 fImpl->fTypeface = tf ? std::move(tf) : SkTypeface::MakeDefault();
18 }
19
~SkShaper()20 SkShaper::~SkShaper() {}
21
good() const22 bool SkShaper::good() const { return true; }
23
24 // This example only uses public API, so we don't use SkUTF8_NextUnichar.
utf8_lead_byte_to_count(const char * ptr)25 unsigned utf8_lead_byte_to_count(const char* ptr) {
26 uint8_t c = *(const uint8_t*)ptr;
27 SkASSERT(c <= 0xF7);
28 SkASSERT((c & 0xC0) != 0x80);
29 return (((0xE5 << 24) >> ((unsigned)c >> 4 << 1)) & 3) + 1;
30 }
31
shape(SkTextBlobBuilder * builder,const SkPaint & srcPaint,const char * utf8text,size_t textBytes,SkPoint point) const32 SkScalar SkShaper::shape(SkTextBlobBuilder* builder,
33 const SkPaint& srcPaint,
34 const char* utf8text,
35 size_t textBytes,
36 SkPoint point) const {
37 SkPaint paint(srcPaint);
38 paint.setTypeface(fImpl->fTypeface);
39 paint.setTextEncoding(SkPaint::kUTF8_TextEncoding);
40 int glyphCount = paint.countText(utf8text, textBytes);
41 if (glyphCount <= 0) {
42 return 0;
43 }
44 SkRect bounds;
45 (void)paint.measureText(utf8text, textBytes, &bounds);
46 paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
47 const SkTextBlobBuilder::RunBuffer& runBuffer =
48 builder->allocRunTextPosH(paint, glyphCount, point.y(), textBytes, SkString(), &bounds);
49 memcpy(runBuffer.utf8text, utf8text, textBytes);
50 const char* txtPtr = utf8text;
51 for (int i = 0; i < glyphCount; ++i) {
52 // Each charater maps to exactly one glyph via SkGlyphCache::unicharToGlyph().
53 runBuffer.clusters[i] = SkToU32(txtPtr - utf8text);
54 txtPtr += utf8_lead_byte_to_count(txtPtr);
55 SkASSERT(txtPtr <= utf8text + textBytes);
56 }
57 paint.setTextEncoding(SkPaint::kUTF8_TextEncoding);
58 (void)paint.textToGlyphs(utf8text, textBytes, runBuffer.glyphs);
59 (void)paint.getTextWidths(utf8text, textBytes, runBuffer.pos);
60 SkScalar x = point.x();
61 for (int i = 0; i < glyphCount; ++i) {
62 SkScalar w = runBuffer.pos[i];
63 runBuffer.pos[i] = x;
64 x += w;
65 }
66 return (SkScalar)x;
67 }
68