SampleHairline.cpp revision a8c183125f2861067daf432cada06d431a795cd0 
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 "SampleCode.h"
9#include "SkView.h"
10#include "SkCanvas.h"
11#include "SkCornerPathEffect.h"
12#include "SkGradientShader.h"
13#include "SkGraphics.h"
14#include "SkImageDecoder.h"
15#include "SkKernel33MaskFilter.h"
16#include "SkPath.h"
17#include "SkRandom.h"
18#include "SkRegion.h"
19#include "SkShader.h"
20#include "SkUtils.h"
21#include "SkColorPriv.h"
22#include "SkColorFilter.h"
23#include "SkTime.h"
24#include "SkTypeface.h"
25#include "SkXfermode.h"
26
27#include "SkStream.h"
28#include "SkXMLParser.h"
29#include "SkColorPriv.h"
30#include "SkImageDecoder.h"
31
32static SkRandom gRand;
33
34static void test_chromium_9005() {
35    SkBitmap bm;
36    bm.allocN32Pixels(800, 600);
37
38    SkCanvas canvas(bm);
39
40    SkPoint pt0 = { 799.33374f, 1.2360189f };
41    SkPoint pt1 = { 808.49969f, -7.4338055f };
42
43    SkPaint paint;
44    paint.setAntiAlias(true);
45    canvas.drawLine(pt0.fX, pt0.fY, pt1.fX, pt1.fY, paint);
46}
47
48static void generate_pts(SkPoint pts[], int count, int w, int h) {
49    for (int i = 0; i < count; i++) {
50        pts[i].set(gRand.nextUScalar1() * 3 * w - SkIntToScalar(w),
51                   gRand.nextUScalar1() * 3 * h - SkIntToScalar(h));
52    }
53}
54
55static bool check_zeros(const SkPMColor pixels[], int count, int skip) {
56    for (int i = 0; i < count; i++) {
57        if (*pixels) {
58            return false;
59        }
60        pixels += skip;
61    }
62    return true;
63}
64
65static bool check_bitmap_margin(const SkBitmap& bm, int margin) {
66    size_t rb = bm.rowBytes();
67    for (int i = 0; i < margin; i++) {
68        if (!check_zeros(bm.getAddr32(0, i), bm.width(), 1)) {
69            return false;
70        }
71        int bottom = bm.height() - i - 1;
72        if (!check_zeros(bm.getAddr32(0, bottom), bm.width(), 1)) {
73            return false;
74        }
75        // left column
76        if (!check_zeros(bm.getAddr32(i, 0), bm.height(), SkToInt(rb >> 2))) {
77            return false;
78        }
79        int right = bm.width() - margin + i;
80        if (!check_zeros(bm.getAddr32(right, 0), bm.height(),
81                         SkToInt(rb >> 2))) {
82            return false;
83        }
84    }
85    return true;
86}
87
88#define WIDTH   620
89#define HEIGHT  460
90#define MARGIN  10
91
92static void line_proc(SkCanvas* canvas, const SkPaint& paint,
93                      const SkBitmap& bm) {
94    const int N = 2;
95    SkPoint pts[N];
96    for (int i = 0; i < 400; i++) {
97        generate_pts(pts, N, WIDTH, HEIGHT);
98
99        canvas->drawLine(pts[0].fX, pts[0].fY, pts[1].fX, pts[1].fY, paint);
100        if (!check_bitmap_margin(bm, MARGIN)) {
101            SkDebugf("---- hairline failure (%g %g) (%g %g)\n",
102                     pts[0].fX, pts[0].fY, pts[1].fX, pts[1].fY);
103            break;
104        }
105    }
106}
107
108static void poly_proc(SkCanvas* canvas, const SkPaint& paint,
109                      const SkBitmap& bm) {
110    const int N = 8;
111    SkPoint pts[N];
112    for (int i = 0; i < 50; i++) {
113        generate_pts(pts, N, WIDTH, HEIGHT);
114
115        SkPath path;
116        path.moveTo(pts[0]);
117        for (int j = 1; j < N; j++) {
118            path.lineTo(pts[j]);
119        }
120        canvas->drawPath(path, paint);
121    }
122}
123
124static SkPoint ave(const SkPoint& a, const SkPoint& b) {
125    SkPoint c = a + b;
126    c.fX = SkScalarHalf(c.fX);
127    c.fY = SkScalarHalf(c.fY);
128    return c;
129}
130
131static void quad_proc(SkCanvas* canvas, const SkPaint& paint,
132                      const SkBitmap& bm) {
133    const int N = 30;
134    SkPoint pts[N];
135    for (int i = 0; i < 10; i++) {
136        generate_pts(pts, N, WIDTH, HEIGHT);
137
138        SkPath path;
139        path.moveTo(pts[0]);
140        for (int j = 1; j < N - 2; j++) {
141            path.quadTo(pts[j], ave(pts[j], pts[j+1]));
142        }
143        path.quadTo(pts[N - 2], pts[N - 1]);
144
145        canvas->drawPath(path, paint);
146    }
147}
148
149static void add_cubic(SkPath* path, const SkPoint& mid, const SkPoint& end) {
150    SkPoint start;
151    path->getLastPt(&start);
152    path->cubicTo(ave(start, mid), ave(mid, end), end);
153}
154
155static void cube_proc(SkCanvas* canvas, const SkPaint& paint,
156                      const SkBitmap& bm) {
157    const int N = 30;
158    SkPoint pts[N];
159    for (int i = 0; i < 10; i++) {
160        generate_pts(pts, N, WIDTH, HEIGHT);
161
162        SkPath path;
163        path.moveTo(pts[0]);
164        for (int j = 1; j < N - 2; j++) {
165            add_cubic(&path, pts[j], ave(pts[j], pts[j+1]));
166        }
167        add_cubic(&path, pts[N - 2], pts[N - 1]);
168
169        canvas->drawPath(path, paint);
170    }
171}
172
173typedef void (*HairProc)(SkCanvas*, const SkPaint&, const SkBitmap&);
174
175static const struct {
176    const char* fName;
177    HairProc    fProc;
178} gProcs[] = {
179    { "line",   line_proc },
180    { "poly",   poly_proc },
181    { "quad",   quad_proc },
182    { "cube",   cube_proc },
183};
184
185static int cycle_hairproc_index(int index) {
186    return (index + 1) % SK_ARRAY_COUNT(gProcs);
187}
188
189class HairlineView : public SampleView {
190    SkMSec fNow;
191    int fProcIndex;
192    bool fDoAA;
193public:
194    HairlineView() {
195        fCounter = 0;
196        fProcIndex = 0;
197        fDoAA = true;
198        fNow = 0;
199    }
200
201protected:
202    // overrides from SkEventSink
203    virtual bool onQuery(SkEvent* evt) {
204        if (SampleCode::TitleQ(*evt)) {
205            SkString str;
206            str.printf("Hair-%s", gProcs[fProcIndex].fName);
207            SampleCode::TitleR(evt, str.c_str());
208            return true;
209        }
210        return this->INHERITED::onQuery(evt);
211    }
212
213    void show_bitmaps(SkCanvas* canvas, const SkBitmap& b0, const SkBitmap& b1,
214                      const SkIRect& inset) {
215        canvas->drawBitmap(b0, 0, 0, NULL);
216        canvas->drawBitmap(b1, SkIntToScalar(b0.width()), 0, NULL);
217    }
218
219    int fCounter;
220
221    virtual void onDrawContent(SkCanvas* canvas) {
222        gRand.setSeed(fNow);
223
224        if (false) { // avoid bit rot, suppress warning
225            test_chromium_9005();
226        }
227
228        SkBitmap bm, bm2;
229        bm.allocN32Pixels(WIDTH + MARGIN*2, HEIGHT + MARGIN*2);
230        // this will erase our margin, which we want to always stay 0
231        bm.eraseColor(SK_ColorTRANSPARENT);
232
233        bm2.installPixels(SkImageInfo::MakeN32Premul(WIDTH, HEIGHT),
234                          bm.getAddr32(MARGIN, MARGIN), bm.rowBytes(),
235                          NULL, NULL);
236
237        SkCanvas c2(bm2);
238        SkPaint paint;
239        paint.setAntiAlias(fDoAA);
240        paint.setStyle(SkPaint::kStroke_Style);
241
242        bm2.eraseColor(SK_ColorTRANSPARENT);
243        gProcs[fProcIndex].fProc(&c2, paint, bm);
244        canvas->drawBitmap(bm2, SkIntToScalar(10), SkIntToScalar(10), NULL);
245
246        SkMSec now = SampleCode::GetAnimTime();
247        if (fNow != now) {
248            fNow = now;
249            fCounter += 1;
250            fDoAA = !fDoAA;
251            if (fCounter > 50) {
252                fProcIndex = cycle_hairproc_index(fProcIndex);
253                // todo: signal that we want to rebuild our TITLE
254                fCounter = 0;
255            }
256            this->inval(NULL);
257        }
258    }
259
260    virtual SkView::Click* onFindClickHandler(SkScalar x, SkScalar y,
261                                              unsigned modi) {
262        fDoAA = !fDoAA;
263        this->inval(NULL);
264        return this->INHERITED::onFindClickHandler(x, y, modi);
265    }
266
267
268private:
269    typedef SampleView INHERITED;
270};
271
272//////////////////////////////////////////////////////////////////////////////
273
274static SkView* MyFactory() { return new HairlineView; }
275static SkViewRegister reg(MyFactory);
276