AuroraMiddleware/skia2
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity
a6e3f6288c
skia2/gm/circulararcs.cpp
Brian Osman e3deee1319 Use a smaller tolerance when chopping conics to quads 
In most places we were using 0.25 (maximum distance between the actual
and approximated curves). In these few places, we were using 0.5, which
is enough to produce visible errors.

Added a GM that demonstrated the problem as reported - many of the arcs
with radius ~8 were previously closer to round-rects than circles.

Bug: chromium:888453
Change-Id: I7d22e27773f56174861526dd0223f52a93bf48eb
Reviewed-on: https://skia-review.googlesource.com/c/172060
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
2018-11-20 16:42:04 +00:00

256 lines
8.8 KiB
C++
Raw Blame History

/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include <functional>
#include "SkCanvas.h"
#include "SkDashPathEffect.h"
#include "gm.h"
constexpr SkScalar kStarts[] = {0.f, 10.f, 30.f, 45.f, 90.f, 165.f, 180.f, 270.f};
constexpr SkScalar kSweeps[] = {1.f, 45.f, 90.f, 130.f, 180.f, 184.f, 300.f, 355.f};
constexpr SkScalar kDiameter = 40.f;
constexpr SkRect kRect = {0.f, 0.f, kDiameter, kDiameter};
constexpr int kW = 1000;
constexpr int kH = 1000;
constexpr SkScalar kPad = 20.f;
void draw_arcs(SkCanvas* canvas, std::function<void(SkPaint*)> configureStyle) {
// Draws grid of arcs with different start/sweep angles in red and their complement arcs in
// blue.
auto drawGrid = [canvas, &configureStyle] (SkScalar x, SkScalar y, bool useCenter, bool aa) {
SkPaint p0;
p0.setColor(SK_ColorRED);
p0.setAntiAlias(aa);
// Set a reasonable stroke width that configureStyle can override.
p0.setStrokeWidth(15.f);
SkPaint p1 = p0;
p1.setColor(SK_ColorBLUE);
// Use alpha so we see magenta on overlap between arc and its complement.
p0.setAlpha(100);
p1.setAlpha(100);
configureStyle(&p0);
configureStyle(&p1);
canvas->save();
canvas->translate(kPad + x, kPad + y);
for (auto start : kStarts) {
canvas->save();
for (auto sweep : kSweeps) {
canvas->drawArc(kRect, start, sweep, useCenter, p0);
canvas->drawArc(kRect, start, -(360.f - sweep), useCenter, p1);
canvas->translate(kRect.width() + kPad, 0.f);
}
canvas->restore();
canvas->translate(0, kRect.height() + kPad);
}
canvas->restore();
};
// Draw a grids for combo of enabling/disabling aa and using center.
constexpr SkScalar kGridW = kW / 2.f;
constexpr SkScalar kGridH = kH / 2.f;
drawGrid(0.f , 0.f , false, false);
drawGrid(kGridW, 0.f , true , false);
drawGrid(0.f , kGridH, false, true );
drawGrid(kGridW, kGridH, true , true );
// Draw separators between the grids.
SkPaint linePaint;
linePaint.setAntiAlias(true);
linePaint.setColor(SK_ColorBLACK);
canvas->drawLine(kGridW, 0.f , kGridW, SkIntToScalar(kH), linePaint);
canvas->drawLine(0.f , kGridH, SkIntToScalar(kW), kGridH, linePaint);
}
#define DEF_ARC_GM(name) DEF_SIMPLE_GM(circular_arcs_##name, canvas, kW, kH)
DEF_ARC_GM(fill) {
auto setFill = [] (SkPaint*p) { p->setStyle(SkPaint::kFill_Style); };
draw_arcs(canvas, setFill);
}
DEF_ARC_GM(hairline) {
auto setHairline = [] (SkPaint* p) {
p->setStyle(SkPaint::kStroke_Style);
p->setStrokeWidth(0.f);
};
draw_arcs(canvas, setHairline);
}
DEF_ARC_GM(stroke_butt) {
auto setStroke = [](SkPaint* p) {
p->setStyle(SkPaint::kStroke_Style);
p->setStrokeCap(SkPaint::kButt_Cap);
};
draw_arcs(canvas, setStroke);
}
DEF_ARC_GM(stroke_square) {
auto setStroke = [] (SkPaint* p) {
p->setStyle(SkPaint::kStroke_Style);
p->setStrokeCap(SkPaint::kSquare_Cap);
};
draw_arcs(canvas, setStroke);
}
DEF_ARC_GM(stroke_round) {
auto setStroke = [] (SkPaint* p) {
p->setStyle(SkPaint::kStroke_Style);
p->setStrokeCap(SkPaint::kRound_Cap);
};
draw_arcs(canvas, setStroke);
}
DEF_ARC_GM(stroke_and_fill_butt) {
auto setStroke = [] (SkPaint* p) {
p->setStyle(SkPaint::kStrokeAndFill_Style);
p->setStrokeCap(SkPaint::kButt_Cap);
};
draw_arcs(canvas, setStroke);
}
DEF_ARC_GM(stroke_and_fill_square) {
auto setStroke = [] (SkPaint* p) {
p->setStyle(SkPaint::kStrokeAndFill_Style);
p->setStrokeCap(SkPaint::kSquare_Cap);
};
draw_arcs(canvas, setStroke);
}
DEF_ARC_GM(stroke_and_fill_round) {
auto setStroke = [] (SkPaint* p) {
p->setStyle(SkPaint::kStrokeAndFill_Style);
p->setStrokeCap(SkPaint::kRound_Cap);
};
draw_arcs(canvas, setStroke);
}
DEF_SIMPLE_GM(circular_arcs_weird, canvas, 1000, 400) {
constexpr SkScalar kS = 50;
struct Arc {
SkRect fOval;
SkScalar fStart;
SkScalar fSweep;
};
const Arc noDrawArcs[] = {
// no sweep
{SkRect::MakeWH(kS, kS), 0, 0},
// empty rect in x
{SkRect::MakeWH(-kS, kS), 0, 90},
// empty rect in y
{SkRect::MakeWH(kS, -kS), 0, 90},
// empty rect in x and y
{SkRect::MakeWH( 0, 0), 0, 90},
};
const Arc arcs[] = {
// large start
{SkRect::MakeWH(kS, kS), 810.f, 90.f},
// large negative start
{SkRect::MakeWH(kS, kS), -810.f, 90.f},
// exactly 360 sweep
{SkRect::MakeWH(kS, kS), 0.f, 360.f},
// exactly -360 sweep
{SkRect::MakeWH(kS, kS), 0.f, -360.f},
// exactly 540 sweep
{SkRect::MakeWH(kS, kS), 0.f, 540.f},
// exactly -540 sweep
{SkRect::MakeWH(kS, kS), 0.f, -540.f},
// generic large sweep and large start
{SkRect::MakeWH(kS, kS), 1125.f, 990.f},
};
SkTArray<SkPaint> paints;
// fill
paints.push_back();
// stroke
paints.push_back().setStyle(SkPaint::kStroke_Style);
paints.back().setStrokeWidth(kS / 6.f);
// hairline
paints.push_back().setStyle(SkPaint::kStroke_Style);
paints.back().setStrokeWidth(0.f);
// stroke and fill
paints.push_back().setStyle(SkPaint::kStrokeAndFill_Style);
paints.back().setStrokeWidth(kS / 6.f);
// dash effect
paints.push_back().setStyle(SkPaint::kStroke_Style);
paints.back().setStrokeWidth(kS / 6.f);
constexpr SkScalar kDashIntervals[] = {kS / 15, 2 * kS / 15};
paints.back().setPathEffect(SkDashPathEffect::Make(kDashIntervals, 2, 0.f));
canvas->translate(kPad, kPad);
// This loop should draw nothing.
for (auto arc : noDrawArcs) {
for (auto paint : paints) {
paint.setAntiAlias(true);
canvas->drawArc(arc.fOval, arc.fStart, arc.fSweep, false, paint);
canvas->drawArc(arc.fOval, arc.fStart, arc.fSweep, true, paint);
}
}
SkPaint linePaint;
linePaint.setAntiAlias(true);
linePaint.setColor(SK_ColorRED);
SkScalar midX = SK_ARRAY_COUNT(arcs) * (kS + kPad) - kPad/2.f;
SkScalar height = paints.count() * (kS + kPad);
canvas->drawLine(midX, -kPad, midX, height, linePaint);
for (auto paint : paints) {
paint.setAntiAlias(true);
canvas->save();
for (auto arc : arcs) {
canvas->drawArc(arc.fOval, arc.fStart, arc.fSweep, false, paint);
canvas->translate(kS + kPad, 0.f);
}
for (auto arc : arcs) {
canvas->drawArc(arc.fOval, arc.fStart, arc.fSweep, true, paint);
canvas->translate(kS + kPad, 0.f);
}
canvas->restore();
canvas->translate(0, kS + kPad);
}
}
DEF_SIMPLE_GM(onebadarc, canvas, 100, 100) {
SkPath path;
path.moveTo(SkBits2Float(0x41a00000), SkBits2Float(0x41a00000)); // 20, 20
path.lineTo(SkBits2Float(0x4208918c), SkBits2Float(0x4208918c)); // 34.1421f, 34.1421f
path.conicTo(SkBits2Float(0x41a00000), SkBits2Float(0x42412318), // 20, 48.2843f
SkBits2Float(0x40bb73a0), SkBits2Float(0x4208918c), // 5.85786f, 34.1421f
SkBits2Float(0x3f3504f3)); // 0.707107f
path.quadTo(SkBits2Float(0x40bb73a0), SkBits2Float(0x4208918c), // 5.85786f, 34.1421f
SkBits2Float(0x40bb73a2), SkBits2Float(0x4208918c)); // 5.85787f, 34.1421f
path.lineTo(SkBits2Float(0x41a00000), SkBits2Float(0x41a00000)); // 20, 20
path.close();
SkPaint p0;
p0.setColor(SK_ColorRED);
p0.setStrokeWidth(15.f);
p0.setStyle(SkPaint::kStroke_Style);
p0.setAlpha(100);
canvas->translate(20, 0);
canvas->drawPath(path, p0);
SkRect kRect = { 60, 0, 100, 40};
canvas->drawArc(kRect, 45, 90, true, p0);
}
DEF_SIMPLE_GM(crbug_888453, canvas, 480, 150) {
// Two GPU path renderers were using a too-large tolerance when chopping connics to quads.
// This manifested as not-very-round circular arcs at certain radii. All the arcs being drawn
// here should look like circles.
SkPaint fill;
fill.setAntiAlias(true);
SkPaint hairline = fill;
hairline.setStyle(SkPaint::kStroke_Style);
SkPaint stroke = hairline;
stroke.setStrokeWidth(2.0f);
int x = 4;
int y0 = 25, y1 = 75, y2 = 125;
for (int r = 2; r <= 20; ++r) {
canvas->drawArc(SkRect::MakeXYWH(x - r, y0 - r, 2 * r, 2 * r), 0, 360, false, fill);
canvas->drawArc(SkRect::MakeXYWH(x - r, y1 - r, 2 * r, 2 * r), 0, 360, false, hairline);
canvas->drawArc(SkRect::MakeXYWH(x - r, y2 - r, 2 * r, 2 * r), 0, 360, false, stroke);
x += 2 * r + 4;
}
}
Reference in New Issue View Git Blame Copy Permalink