| /* |
| * Copyright 2018 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include <string> |
| #include "include/core/SkCanvas.h" |
| #include "include/core/SkFont.h" |
| #include "include/core/SkPath.h" |
| #include "samplecode/Sample.h" |
| #include "src/core/SkGeometry.h" |
| #include "tools/timer/AnimTimer.h" |
| |
| // This draws an animation where every cubic has a cusp, to test drawing a circle |
| // at the cusp point. Create a unit square. A cubic with its control points |
| // at the four corners crossing over itself has a cusp. |
| |
| // Project the unit square through a random affine matrix. |
| // Chop the cubic in two. One half of the cubic will have a cusp |
| // (unless it was chopped exactly at the cusp point). |
| |
| // Running this looks mostly OK, but will occasionally draw something odd. |
| // The odd parts don't appear related to the cusp code, but are old stroking |
| // bugs that have not been fixed, yet. |
| |
| SkMSec start = 0; |
| SkMSec curTime; |
| bool first = true; |
| |
| // Create a path with one or two cubics, where one has a cusp. |
| static SkPath cusp(const SkPoint P[4], SkPoint PP[7], bool& split, int speed, SkScalar phase) { |
| SkPath path; |
| path.moveTo(P[0]); |
| SkScalar t = (curTime % speed) / SkIntToFloat(speed); |
| t += phase; |
| if (t > 1) { |
| t -= 1; |
| } |
| if (0 <= t || t >= 1) { |
| path.cubicTo(P[1], P[2], P[3]); |
| split = false; |
| } else { |
| SkChopCubicAt(P, PP, t); |
| path.cubicTo(PP[1], PP[2], PP[3]); |
| path.cubicTo(PP[4], PP[5], PP[6]); |
| split = true; |
| } |
| return path; |
| } |
| |
| // Scale the animation counter to a value that oscillates from -scale to +scale. |
| static SkScalar linearToLoop(int speed, SkScalar phase, SkScalar scale) { |
| SkScalar loop; |
| SkScalar linear = (curTime % speed) / SkIntToFloat(speed); // 0 to 1 |
| linear += phase; |
| if (linear > 1) { |
| linear -= 1; |
| } |
| if (linear < .25) { |
| loop = linear * 4; // 0 to .25 ==> 0 to 1 |
| } else if (linear < .75) { // .25 to .75 ==> 1 to -1 |
| loop = (.5 - linear) * 4; |
| } else { // .75 to 1 ==> -1 to 0 |
| loop = (linear - 1) * 4; |
| } |
| return loop * scale; |
| } |
| |
| struct data { |
| SkIPoint pt[4]; |
| } dat[] = { |
| // When the animation looks funny, pause, and paste the last part of the stream in stdout here. |
| // Enable the 1st #if to play the recorded stream backwards. |
| // Enable the 2nd #if and replace the second 'i = ##' with the value of datCount that shows the bug. |
| {{{0x43480000,0x43960000},{0x4318b999,0x4321570b},{0x432f999a,0x435a0a3d},{0x43311fff,0x43734cce},}}, |
| {{{0x43480000,0x43960000},{0x431d1ddf,0x4321ae13},{0x4331ddde,0x435c147c},{0x43334001,0x43719997},}}, |
| {{{0x43480000,0x43960000},{0x43218224,0x43220520},{0x43342223,0x435e1eba},{0x43356001,0x436fe666},}}, |
| {{{0x43480000,0x43960000},{0x4325a445,0x43225708},{0x43364444,0x43600a3c},{0x43376001,0x436e4ccc},}}, |
| {{{0x43480000,0x43960000},{0x432a0889,0x4322ae16},{0x43388889,0x4362147b},{0x43398000,0x436c999b},}}, |
| {{{0x43480000,0x43960000},{0x432e6ccd,0x43230523},{0x433acccd,0x43641eba},{0x433ba000,0x436ae66a},}}, |
| {{{0x43480000,0x43960000},{0x43328eef,0x4323570c},{0x433ceeee,0x43660a3c},{0x433da000,0x43694cd0},}}, |
| {{{0x43480000,0x43960000},{0x4336f333,0x4323ae13},{0x433f3333,0x4368147a},{0x433fc000,0x43679998},}}, |
| {{{0x43480000,0x43960000},{0x433b5777,0x43240520},{0x43417777,0x436a1eb9},{0x4341e000,0x4365e668},}}, |
| {{{0x43480000,0x43960000},{0x433f799a,0x4324570c},{0x4343999a,0x436c0a3e},{0x4343e000,0x43644cce},}}, |
| {{{0x43480000,0x43960000},{0x4343ddde,0x4324ae13},{0x4345dddf,0x436e147c},{0x43460000,0x43629996},}}, |
| {{{0x43480000,0x43960000},{0x43484222,0x4325051e},{0x43482222,0x43701eb9},{0x43481fff,0x4360e666},}}, |
| {{{0x43480000,0x43960000},{0x434c6446,0x43255709},{0x434a4444,0x43720a3e},{0x434a2002,0x435f4ccc},}}, |
| {{{0x43480000,0x43960000},{0x4350c888,0x4325ae16},{0x434c8889,0x4374147c},{0x434c3fff,0x435d999a},}}, |
| {{{0x43480000,0x43960000},{0x43552cce,0x43260521},{0x434ecccd,0x43761eb8},{0x434e6001,0x435be669},}}, |
| {{{0x43480000,0x43960000},{0x43594eee,0x4326570c},{0x4350eeef,0x43780a3d},{0x43505fff,0x435a4ccf},}}, |
| {{{0x43480000,0x43960000},{0x435db334,0x4326ae19},{0x43533333,0x437a147c},{0x43528001,0x4358999e},}}, |
| {{{0x43480000,0x43960000},{0x4361d555,0x43270002},{0x43555555,0x437bfffe},{0x43547fff,0x43570004},}}, |
| {{{0x43480000,0x43960000},{0x4366399a,0x4327570c},{0x4357999a,0x437e0a3f},{0x4356a001,0x43554ccd},}}, |
| {{{0x43480000,0x43960000},{0x436a9ddc,0x4327ae12},{0x4359ddde,0x43800a3e},{0x4358bffe,0x43539996},}}, |
| {{{0x43480000,0x43960000},{0x436f0222,0x4328051c},{0x435c2222,0x43810f5c},{0x435ae000,0x4351e664},}}, |
| }; |
| |
| size_t datCount = SK_ARRAY_COUNT(dat); |
| |
| class CuspView : public Sample { |
| public: |
| CuspView() {} |
| protected: |
| bool onQuery(Sample::Event* evt) override { |
| if (Sample::TitleQ(*evt)) { |
| Sample::TitleR(evt, "Cusp"); |
| return true; |
| } |
| return this->INHERITED::onQuery(evt); |
| } |
| |
| void onDrawContent(SkCanvas* canvas) override { |
| SkPaint p; |
| p.setAntiAlias(true); |
| p.setStyle(SkPaint::kStroke_Style); |
| p.setStrokeWidth(20); |
| #if 0 // enable to play through the stream above backwards. |
| SkPath path; |
| int i; |
| #if 0 // disable to draw only one problematic cubic |
| i = --datCount; |
| #else |
| i = 14; // index into dat of problematic cubic |
| #endif |
| path.moveTo( SkBits2Float(dat[i].pt[0].fX), SkBits2Float(dat[i].pt[0].fY)); |
| path.cubicTo(SkBits2Float(dat[i].pt[1].fX), SkBits2Float(dat[i].pt[1].fY), |
| SkBits2Float(dat[i].pt[2].fX), SkBits2Float(dat[i].pt[2].fY), |
| SkBits2Float(dat[i].pt[3].fX), SkBits2Float(dat[i].pt[3].fY)); |
| #else |
| SkPath path; |
| SkRect rect; |
| rect.setWH(100, 100); |
| SkMatrix matrix; |
| SkScalar vals[9]; |
| vals[0] = linearToLoop(3000, 0, 1); |
| vals[1] = linearToLoop(4000, .25, 1.25); |
| vals[2] = 200; |
| vals[3] = linearToLoop(5000, .5, 1.5); |
| vals[4] = linearToLoop(7000, .75, 1.75); |
| vals[5] = 300; |
| vals[6] = 0; |
| vals[7] = 0; |
| vals[8] = 1; |
| matrix.set9(vals); |
| SkPoint pts[4], pp[7]; |
| matrix.mapRectToQuad(pts, rect); |
| std::swap(pts[1], pts[2]); |
| bool split; |
| path = cusp(pts, pp, split, 8000, .125); |
| auto debugOutCubic = [](const SkPoint* pts) { |
| return false; // comment out to capture stream of cusp'd cubics in stdout |
| SkDebugf("{{"); |
| for (int i = 0; i < 4; ++i) { |
| SkDebugf("{0x%08x,0x%08x},", SkFloat2Bits(pts[i].fX), SkFloat2Bits(pts[i].fY)); |
| } |
| SkDebugf("}},\n"); |
| }; |
| if (split) { |
| debugOutCubic(&pp[0]); |
| debugOutCubic(&pp[4]); |
| } else { |
| debugOutCubic(&pts[0]); |
| } |
| #endif |
| canvas->drawPath(path, p); |
| // draw time to make it easier to guess when the bad cubic was drawn |
| std::string timeStr = std::to_string((float) (curTime - start) / 1000.f); |
| canvas->drawSimpleText(timeStr.c_str(), timeStr.size(), SkTextEncoding::kUTF8, 20, 20, SkFont(), SkPaint()); |
| SkDebugf(""); |
| } |
| |
| bool onAnimate(const AnimTimer& timer) override { |
| curTime = timer.msec(); |
| if (!start) { |
| start = curTime; |
| } |
| return true; |
| } |
| |
| private: |
| |
| typedef Sample INHERITED; |
| }; |
| |
| DEF_SAMPLE( return new CuspView(); ) |
