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skia2/gm/smallarc.cpp

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Draw more accurate thick-stroked Beziers (disabled) Draw thick-stroked Beziers by computing the outset quadratic, measuring the error, and subdividing until the error is within a predetermined limit. To try this CL out, change src/core/SkStroke.h:18 to #define QUAD_STROKE_APPROXIMATION 1 or from the command line: CPPFLAGS="-D QUAD_STROKE_APPROXIMATION=1" ./gyp_skia Here's what's in this CL: bench/BezierBench.cpp : a microbench for examining where the time is going gm/beziers.cpp : random Beziers with various thicknesses gm/smallarc.cpp : a distillation of bug skia:2769 samplecode/SampleRotateCircles.cpp : controls added for error, limit, width src/core/SkStroke.cpp : the new stroke implementation (disabled) tests/StrokerTest.cpp : a stroke torture test that checks normal and extreme values The new stroke algorithm has a tweakable parameter: stroker.setError(1); (SkStrokeRec.cpp:112) The stroke error is the allowable gap between the midpoint of the stroke quadratic and the center Bezier. As the projection from the quadratic approaches the endpoints, the error is decreased proportionally so that it is always inside the quadratic curve. An overview of how this works: - For a given T range of a Bezier, compute the perpendiculars and find the points outset and inset for some radius. - Construct tangents for the quadratic stroke. - If the tangent don't intersect between them (may happen with cubics), subdivide. - If the quadratic stroke end points are close (again, may happen with cubics), draw a line between them. - Compute the quadratic formed by the intersecting tangents. - If the midpoint of the quadratic is close to the midpoint of the Bezier perpendicular, return the quadratic. - If the end of the stroke at the Bezier midpoint doesn't intersect the quad's bounds, subdivide. - Find where the Bezier midpoint ray intersects the quadratic. - If the intersection is too close to the quad's endpoints, subdivide. - If the error is large proportional to the intersection's distance to the quad's endpoints, subdivide. BUG=skia:723,skia:2769 Review URL: https://codereview.chromium.org/558163005
2014-10-09 12:36:03 +00:00
/*
* Copyright 2014 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
rewrite includes to not need so much -Ifoo Current strategy: everything from the top Things to look at first are the manual changes: - added tools/rewrite_includes.py - removed -Idirectives from BUILD.gn - various compile.sh simplifications - tweak tools/embed_resources.py - update gn/find_headers.py to write paths from the top - update gn/gn_to_bp.py SkUserConfig.h layout so that #include "include/config/SkUserConfig.h" always gets the header we want. No-Presubmit: true Change-Id: I73a4b181654e0e38d229bc456c0d0854bae3363e Reviewed-on: https://skia-review.googlesource.com/c/skia/+/209706 Commit-Queue: Mike Klein <mtklein@google.com> Reviewed-by: Hal Canary <halcanary@google.com> Reviewed-by: Brian Osman <brianosman@google.com> Reviewed-by: Florin Malita <fmalita@chromium.org>
2019-04-23 17:05:21 +00:00
#include "gm/gm.h"
IWYU for gms. This almost gets gms to be iwyu clean. The last bit is around gm.cpp and the tracing framework and its use of atomic. Will also need a way of keeping things from regressing, which is difficult due to needing to do this outside-in. Change-Id: I1393531e99da8b0f1a29f55c53c86d53f459af7d Reviewed-on: https://skia-review.googlesource.com/c/skia/+/211593 Reviewed-by: Herb Derby <herb@google.com> Commit-Queue: Ben Wagner <bungeman@google.com>
2019-05-01 21:28:53 +00:00
#include "include/core/SkCanvas.h"
#include "include/core/SkColor.h"
#include "include/core/SkPaint.h"
rewrite includes to not need so much -Ifoo Current strategy: everything from the top Things to look at first are the manual changes: - added tools/rewrite_includes.py - removed -Idirectives from BUILD.gn - various compile.sh simplifications - tweak tools/embed_resources.py - update gn/find_headers.py to write paths from the top - update gn/gn_to_bp.py SkUserConfig.h layout so that #include "include/config/SkUserConfig.h" always gets the header we want. No-Presubmit: true Change-Id: I73a4b181654e0e38d229bc456c0d0854bae3363e Reviewed-on: https://skia-review.googlesource.com/c/skia/+/209706 Commit-Queue: Mike Klein <mtklein@google.com> Reviewed-by: Hal Canary <halcanary@google.com> Reviewed-by: Brian Osman <brianosman@google.com> Reviewed-by: Florin Malita <fmalita@chromium.org>
2019-04-23 17:05:21 +00:00
#include "include/core/SkPath.h"
Draw more accurate thick-stroked Beziers (disabled) Draw thick-stroked Beziers by computing the outset quadratic, measuring the error, and subdividing until the error is within a predetermined limit. To try this CL out, change src/core/SkStroke.h:18 to #define QUAD_STROKE_APPROXIMATION 1 or from the command line: CPPFLAGS="-D QUAD_STROKE_APPROXIMATION=1" ./gyp_skia Here's what's in this CL: bench/BezierBench.cpp : a microbench for examining where the time is going gm/beziers.cpp : random Beziers with various thicknesses gm/smallarc.cpp : a distillation of bug skia:2769 samplecode/SampleRotateCircles.cpp : controls added for error, limit, width src/core/SkStroke.cpp : the new stroke implementation (disabled) tests/StrokerTest.cpp : a stroke torture test that checks normal and extreme values The new stroke algorithm has a tweakable parameter: stroker.setError(1); (SkStrokeRec.cpp:112) The stroke error is the allowable gap between the midpoint of the stroke quadratic and the center Bezier. As the projection from the quadratic approaches the endpoints, the error is decreased proportionally so that it is always inside the quadratic curve. An overview of how this works: - For a given T range of a Bezier, compute the perpendiculars and find the points outset and inset for some radius. - Construct tangents for the quadratic stroke. - If the tangent don't intersect between them (may happen with cubics), subdivide. - If the quadratic stroke end points are close (again, may happen with cubics), draw a line between them. - Compute the quadratic formed by the intersecting tangents. - If the midpoint of the quadratic is close to the midpoint of the Bezier perpendicular, return the quadratic. - If the end of the stroke at the Bezier midpoint doesn't intersect the quad's bounds, subdivide. - Find where the Bezier midpoint ray intersects the quadratic. - If the intersection is too close to the quad's endpoints, subdivide. - If the error is large proportional to the intersection's distance to the quad's endpoints, subdivide. BUG=skia:723,skia:2769 Review URL: https://codereview.chromium.org/558163005
2014-10-09 12:36:03 +00:00
// this draws a small arc scaled up
// see https://code.google.com/p/chromium/issues/detail?id=102411
// and https://code.google.com/p/skia/issues/detail?id=2769
GM: replace boilerplate with macros I have verified locally that nothing draws differently. Motivation: * SK_SIMPLE_GM makes it easier to write a GM. * Reducing 1100 lines of code makes maintenance easier. * Simple GMs are easy to convert to Fiddles. Review URL: https://codereview.chromium.org/1333553002
2015-09-09 15:16:41 +00:00
DEF_SIMPLE_GM(smallarc, canvas, 762, 762) {
Draw more accurate thick-stroked Beziers (disabled) Draw thick-stroked Beziers by computing the outset quadratic, measuring the error, and subdividing until the error is within a predetermined limit. To try this CL out, change src/core/SkStroke.h:18 to #define QUAD_STROKE_APPROXIMATION 1 or from the command line: CPPFLAGS="-D QUAD_STROKE_APPROXIMATION=1" ./gyp_skia Here's what's in this CL: bench/BezierBench.cpp : a microbench for examining where the time is going gm/beziers.cpp : random Beziers with various thicknesses gm/smallarc.cpp : a distillation of bug skia:2769 samplecode/SampleRotateCircles.cpp : controls added for error, limit, width src/core/SkStroke.cpp : the new stroke implementation (disabled) tests/StrokerTest.cpp : a stroke torture test that checks normal and extreme values The new stroke algorithm has a tweakable parameter: stroker.setError(1); (SkStrokeRec.cpp:112) The stroke error is the allowable gap between the midpoint of the stroke quadratic and the center Bezier. As the projection from the quadratic approaches the endpoints, the error is decreased proportionally so that it is always inside the quadratic curve. An overview of how this works: - For a given T range of a Bezier, compute the perpendiculars and find the points outset and inset for some radius. - Construct tangents for the quadratic stroke. - If the tangent don't intersect between them (may happen with cubics), subdivide. - If the quadratic stroke end points are close (again, may happen with cubics), draw a line between them. - Compute the quadratic formed by the intersecting tangents. - If the midpoint of the quadratic is close to the midpoint of the Bezier perpendicular, return the quadratic. - If the end of the stroke at the Bezier midpoint doesn't intersect the quad's bounds, subdivide. - Find where the Bezier midpoint ray intersects the quadratic. - If the intersection is too close to the quad's endpoints, subdivide. - If the error is large proportional to the intersection's distance to the quad's endpoints, subdivide. BUG=skia:723,skia:2769 Review URL: https://codereview.chromium.org/558163005
2014-10-09 12:36:03 +00:00
SkPaint p;
p.setColor(SK_ColorRED);
p.setAntiAlias(true);
p.setStyle(SkPaint::kStroke_Style);
p.setStrokeWidth(120);
SkPath path;
path.moveTo(75, 0);
path.cubicTo(33.5, 0, 0, 33.5, 0, 75);
canvas->translate(-400, -400);
canvas->scale(8, 8);
canvas->drawPath(path, p);
}
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