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1 /*
2  * Copyright 2011 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 
8 #include "gm/gm.h"
9 #include "include/core/SkCanvas.h"
10 #include "include/core/SkFont.h"
11 #include "include/core/SkFontStyle.h"
12 #include "include/core/SkFontTypes.h"
13 #include "include/core/SkPaint.h"
14 #include "include/core/SkPath.h"
15 #include "include/core/SkPoint.h"
16 #include "include/core/SkRect.h"
17 #include "include/core/SkRefCnt.h"
18 #include "include/core/SkScalar.h"
19 #include "include/core/SkTextBlob.h"
20 #include "include/core/SkTypeface.h"
21 #include "include/core/SkTypes.h"
22 #include "include/private/SkTDArray.h"
23 #include "include/private/SkTemplates.h"
24 #include "include/private/SkTo.h"
25 #include "tools/ToolUtils.h"
26 
27 #include <string.h>
28 
create_underline(const SkTDArray<SkScalar> & intersections,SkScalar last,SkScalar finalPos,SkScalar uPos,SkScalar uWidth,SkScalar textSize)29 static SkPath create_underline(const SkTDArray<SkScalar>& intersections,
30         SkScalar last, SkScalar finalPos,
31         SkScalar uPos, SkScalar uWidth, SkScalar textSize) {
32     SkPath underline;
33     SkScalar end = last;
34     for (int index = 0; index < intersections.count(); index += 2) {
35         SkScalar start = intersections[index] - uWidth;
36         end = intersections[index + 1] + uWidth;
37         if (start > last && last + textSize / 12 < start) {
38             underline.moveTo(last, uPos);
39             underline.lineTo(start, uPos);
40         }
41         last = end;
42     }
43     if (end < finalPos) {
44         underline.moveTo(end, uPos);
45         underline.lineTo(finalPos, uPos);
46     }
47     return underline;
48 }
49 
50 namespace {
51 
MakeFancyBlob(const SkPaint & paint,const SkFont & font,const char * text)52 sk_sp<SkTextBlob> MakeFancyBlob(const SkPaint& paint, const SkFont& font, const char* text) {
53     const size_t textLen = strlen(text);
54     const int glyphCount = font.countText(text, textLen, SkTextEncoding::kUTF8);
55     SkAutoTArray<SkGlyphID> glyphs(glyphCount);
56     font.textToGlyphs(text, textLen, SkTextEncoding::kUTF8, glyphs.get(), glyphCount);
57     SkAutoTArray<SkScalar> widths(glyphCount);
58     font.getWidths(glyphs.get(), glyphCount, widths.get());
59 
60     SkTextBlobBuilder blobBuilder;
61     int glyphIndex = 0;
62     SkScalar advance = 0;
63 
64     // Default-positioned run.
65     {
66         const int defaultRunLen = glyphCount / 3;
67         const SkTextBlobBuilder::RunBuffer& buf = blobBuilder.allocRun(font,
68                                                                        defaultRunLen,
69                                                                        advance, 0);
70         memcpy(buf.glyphs, glyphs.get(), SkTo<uint32_t>(defaultRunLen) * sizeof(SkGlyphID));
71 
72         for (int i = 0; i < defaultRunLen; ++i) {
73             advance += widths[glyphIndex++];
74         }
75     }
76 
77     // Horizontal-positioned run.
78     {
79         const int horizontalRunLen = glyphCount / 3;
80         const SkTextBlobBuilder::RunBuffer& buf = blobBuilder.allocRunPosH(font,
81                                                                            horizontalRunLen,
82                                                                            0);
83         memcpy(buf.glyphs, glyphs.get() + glyphIndex,
84                SkTo<uint32_t>(horizontalRunLen) * sizeof(SkGlyphID));
85         for (int i = 0; i < horizontalRunLen; ++i) {
86             buf.pos[i] = advance;
87             advance += widths[glyphIndex++];
88         }
89     }
90 
91     // Full-positioned run.
92     {
93         const int fullRunLen = glyphCount - glyphIndex;
94         const SkTextBlobBuilder::RunBuffer& buf = blobBuilder.allocRunPos(font, fullRunLen);
95         memcpy(buf.glyphs, glyphs.get() + glyphIndex,
96                SkTo<uint32_t>(fullRunLen) * sizeof(SkGlyphID));
97         for (int i = 0; i < fullRunLen; ++i) {
98             buf.pos[i * 2 + 0] = advance; // x offset
99             buf.pos[i * 2 + 1] = 0;       // y offset
100             advance += widths[glyphIndex++];
101         }
102     }
103 
104     return blobBuilder.make();
105 }
106 
107 } // anonymous ns
108 
109 DEF_SIMPLE_GM(fancyblobunderline, canvas, 1480, 1380) {
110     SkPaint paint;
111     paint.setAntiAlias(true);
112     const char* fam[] = { "sans-serif", "serif", "monospace" };
113     const char test[] = "aAjJgGyY_|{-(~[,]qQ}pP}zZ";
114     const SkPoint blobOffset = { 10, 80 };
115 
116     for (size_t font = 0; font < SK_ARRAY_COUNT(fam); ++font) {
117         for (SkScalar textSize = 100; textSize > 10; textSize -= 20) {
118             SkFont skFont(ToolUtils::create_portable_typeface(fam[font], SkFontStyle()), textSize);
119             const SkScalar uWidth = textSize / 15;
120             paint.setStrokeWidth(uWidth);
121             paint.setStyle(SkPaint::kFill_Style);
122 
123             sk_sp<SkTextBlob> blob = MakeFancyBlob(paint, skFont, test);
124             canvas->drawTextBlob(blob, blobOffset.x(), blobOffset.y(), paint);
125 
126             const SkScalar uPos = uWidth;
127             const SkScalar bounds[2] = { uPos - uWidth / 2, uPos + uWidth / 2 };
128             const int interceptCount = blob->getIntercepts(bounds, nullptr, &paint);
129             SkASSERT(!(interceptCount % 2));
130 
131             SkTDArray<SkScalar> intercepts;
132             intercepts.setCount(interceptCount);
133             blob->getIntercepts(bounds, intercepts.begin(), &paint);
134 
135             const SkScalar start = blob->bounds().left();
136             const SkScalar end = blob->bounds().right();
137             SkPath underline = create_underline(intercepts, start, end, uPos, uWidth, textSize);
138             underline.offset(blobOffset.x(), blobOffset.y());
139             paint.setStyle(SkPaint::kStroke_Style);
140             canvas->drawPath(underline, paint);
141 
142             canvas->translate(0, textSize * 1.3f);
143         }
144 
145         canvas->translate(0, 60);
146     }
147 }
148 
149 ///////////////////////////////////////////////////////////////////////////////////////////////////
150 
make_text(const SkFont & font,const SkGlyphID glyphs[],int count)151 static sk_sp<SkTextBlob> make_text(const SkFont& font, const SkGlyphID glyphs[], int count) {
152     return SkTextBlob::MakeFromText(glyphs, count * sizeof(SkGlyphID), font,
153                                     SkTextEncoding::kGlyphID);
154 }
155 
make_posh(const SkFont & font,const SkGlyphID glyphs[],int count,SkScalar spacing)156 static sk_sp<SkTextBlob> make_posh(const SkFont& font, const SkGlyphID glyphs[], int count,
157                                    SkScalar spacing) {
158     SkAutoTArray<SkScalar> xpos(count);
159     font.getXPos(glyphs, count, xpos.get());
160     for (int i = 1; i < count; ++i) {
161         xpos[i] += spacing * i;
162     }
163     return SkTextBlob::MakeFromPosTextH(glyphs, count * sizeof(SkGlyphID), xpos.get(), 0, font,
164                                         SkTextEncoding::kGlyphID);
165 }
166 
make_pos(const SkFont & font,const SkGlyphID glyphs[],int count,SkScalar spacing)167 static sk_sp<SkTextBlob> make_pos(const SkFont& font, const SkGlyphID glyphs[], int count,
168                                   SkScalar spacing) {
169     SkAutoTArray<SkPoint> pos(count);
170     font.getPos(glyphs, count, pos.get());
171     for (int i = 1; i < count; ++i) {
172         pos[i].fX += spacing * i;
173     }
174     return SkTextBlob::MakeFromPosText(glyphs, count * sizeof(SkGlyphID), pos.get(), font,
175                                        SkTextEncoding::kGlyphID);
176 }
177 
178 // widen the gaps with a margin (on each side of the gap), elimnating segments that go away
trim_with_halo(SkScalar intervals[],int count,SkScalar margin)179 static int trim_with_halo(SkScalar intervals[], int count, SkScalar margin) {
180     SkASSERT(count > 0 && (count & 1) == 0);
181 
182     int n = count;
183     SkScalar* stop = intervals + count;
184     *intervals++ -= margin;
185     while (intervals < stop - 1) {
186         intervals[0] += margin;
187         intervals[1] -= margin;
188         if (intervals[0] >= intervals[1]) { // went away
189             int remaining = stop - intervals - 2;
190             SkASSERT(remaining >= 0 && (remaining & 1) == 1);
191             if (remaining > 0) {
192                 memmove(intervals, intervals + 2, remaining * sizeof(SkScalar));
193             }
194             stop -= 2;
195             n -= 2;
196         } else {
197             intervals += 2;
198         }
199     }
200     *intervals += margin;
201     return n;
202 }
203 
draw_blob_adorned(SkCanvas * canvas,sk_sp<SkTextBlob> blob)204 static void draw_blob_adorned(SkCanvas* canvas, sk_sp<SkTextBlob> blob) {
205     SkPaint paint;
206 
207     canvas->drawTextBlob(blob.get(), 0, 0, paint);
208 
209     const SkScalar yminmax[] = { 8, 16 };
210     int count = blob->getIntercepts(yminmax, nullptr);
211     if (!count) {
212         return;
213     }
214 
215     SkAutoTArray<SkScalar> intervals(count);
216     blob->getIntercepts(yminmax, intervals.get());
217     count = trim_with_halo(intervals.get(), count, SkScalarHalf(yminmax[1] - yminmax[0]) * 1.5f);
218     SkASSERT(count >= 2);
219 
220     const SkScalar y = SkScalarAve(yminmax[0], yminmax[1]);
221     SkScalar end = 900;
222     SkPath path;
223     path.moveTo({0, y});
224     for (int i = 0; i < count; i += 2) {
225         path.lineTo(intervals[i], y).moveTo(intervals[i+1], y);
226     }
227     if (intervals[count - 1] < end) {
228         path.lineTo(end, y);
229     }
230 
231     paint.setAntiAlias(true);
232     paint.setStyle(SkPaint::kStroke_Style);
233     paint.setStrokeWidth(yminmax[1] - yminmax[0]);
234     canvas->drawPath(path, paint);
235 }
236 
237 DEF_SIMPLE_GM(textblob_intercepts, canvas, 940, 800) {
238     const char text[] = "Hyjay {worlp}.";
239     const size_t length = strlen(text);
240     SkFont font;
241     font.setTypeface(ToolUtils::create_portable_typeface());
242     font.setSize(100);
243     font.setEdging(SkFont::Edging::kAntiAlias);
244     const int count = font.countText(text, length, SkTextEncoding::kUTF8);
245     SkAutoTArray<SkGlyphID> glyphs(count);
246     font.textToGlyphs(text, length, SkTextEncoding::kUTF8, glyphs.get(), count);
247 
248     auto b0 = make_text(font, glyphs.get(), count);
249 
250     canvas->translate(20, 120);
251     draw_blob_adorned(canvas, b0);
252     for (SkScalar spacing = 0; spacing < 30; spacing += 20) {
253         auto b1 = make_posh(font, glyphs.get(), count, spacing);
254         auto b2 = make_pos( font, glyphs.get(), count, spacing);
255         canvas->translate(0, 150);
256         draw_blob_adorned(canvas, b1);
257         canvas->translate(0, 150);
258         draw_blob_adorned(canvas, b2);
259     }
260 }
261