skia2/gm/convexpaths.cpp
bsalomon@google.com a51ab8416d Preserve convex control point polygon in cubic->quadratic approximation
GM test modified, will require rebaselining.

Review URL: http://codereview.appspot.com/6355088/





git-svn-id: http://skia.googlecode.com/svn/trunk@4518 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-07-10 19:53:34 +00:00

244 lines
9.5 KiB
C++

/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "gm.h"
#include "SkRandom.h"
#include "SkTArray.h"
class SkOnce : SkNoncopyable {
public:
SkOnce() { fDidOnce = false; }
bool needToDo() const { return !fDidOnce; }
bool alreadyDone() const { return fDidOnce; }
void accomplished() {
SkASSERT(!fDidOnce);
fDidOnce = true;
}
private:
bool fDidOnce;
};
namespace skiagm {
class ConvexPathsGM : public GM {
SkOnce fOnce;
public:
ConvexPathsGM() {
this->setBGColor(0xFF000000);
}
protected:
virtual SkString onShortName() {
return SkString("convexpaths");
}
virtual SkISize onISize() {
return make_isize(1200, 900);
}
void makePaths() {
if (fOnce.alreadyDone()) {
return;
}
fOnce.accomplished();
// CW
fPaths.push_back().moveTo(0, 0);
fPaths.back().quadTo(50 * SK_Scalar1, 100 * SK_Scalar1,
0, 100 * SK_Scalar1);
fPaths.back().lineTo(0, 0);
// CCW
fPaths.push_back().moveTo(0, 0);
fPaths.back().lineTo(0, 100 * SK_Scalar1);
fPaths.back().quadTo(50 * SK_Scalar1, 100 * SK_Scalar1,
0, 0);
// CW
fPaths.push_back().moveTo(0, 50 * SK_Scalar1);
fPaths.back().quadTo(50 * SK_Scalar1, 0,
100 * SK_Scalar1, 50 * SK_Scalar1);
fPaths.back().quadTo(50 * SK_Scalar1, 100 * SK_Scalar1,
0, 50 * SK_Scalar1);
// CCW
fPaths.push_back().moveTo(0, 50 * SK_Scalar1);
fPaths.back().quadTo(50 * SK_Scalar1, 100 * SK_Scalar1,
100 * SK_Scalar1, 50 * SK_Scalar1);
fPaths.back().quadTo(50 * SK_Scalar1, 0,
0, 50 * SK_Scalar1);
fPaths.push_back().addRect(0, 0,
100 * SK_Scalar1, 100 * SK_Scalar1,
SkPath::kCW_Direction);
fPaths.push_back().addRect(0, 0,
100 * SK_Scalar1, 100 * SK_Scalar1,
SkPath::kCCW_Direction);
fPaths.push_back().addCircle(50 * SK_Scalar1, 50 * SK_Scalar1,
50 * SK_Scalar1, SkPath::kCW_Direction);
fPaths.push_back().addCircle(50 * SK_Scalar1, 50 * SK_Scalar1,
40 * SK_Scalar1, SkPath::kCCW_Direction);
fPaths.push_back().addOval(SkRect::MakeXYWH(0, 0,
50 * SK_Scalar1,
100 * SK_Scalar1),
SkPath::kCW_Direction);
fPaths.push_back().addOval(SkRect::MakeXYWH(0, 0,
100 * SK_Scalar1,
50 * SK_Scalar1),
SkPath::kCCW_Direction);
fPaths.push_back().addOval(SkRect::MakeXYWH(0, 0,
100 * SK_Scalar1,
5 * SK_Scalar1),
SkPath::kCCW_Direction);
fPaths.push_back().addOval(SkRect::MakeXYWH(0, 0,
SK_Scalar1,
100 * SK_Scalar1),
SkPath::kCCW_Direction);
fPaths.push_back().addRoundRect(SkRect::MakeXYWH(0, 0,
SK_Scalar1 * 100,
SK_Scalar1 * 100),
40 * SK_Scalar1, 20 * SK_Scalar1,
SkPath::kCW_Direction);
fPaths.push_back().addRoundRect(SkRect::MakeXYWH(0, 0,
SK_Scalar1 * 100,
SK_Scalar1 * 100),
20 * SK_Scalar1, 40 * SK_Scalar1,
SkPath::kCCW_Direction);
// shallow diagonals
fPaths.push_back().lineTo(100 * SK_Scalar1, SK_Scalar1);
fPaths.back().lineTo(98 * SK_Scalar1, 100 * SK_Scalar1);
fPaths.back().lineTo(3 * SK_Scalar1, 96 * SK_Scalar1);
/*
It turns out arcTos are not automatically marked as convex and they
may in fact be ever so slightly concave.
fPaths.push_back().arcTo(SkRect::MakeXYWH(0, 0,
50 * SK_Scalar1,
100 * SK_Scalar1),
25 * SK_Scalar1, 130 * SK_Scalar1, false);
*/
// cubics
fPaths.push_back().cubicTo( 1 * SK_Scalar1, 1 * SK_Scalar1,
10 * SK_Scalar1, 90 * SK_Scalar1,
0 * SK_Scalar1, 100 * SK_Scalar1);
fPaths.push_back().cubicTo(100 * SK_Scalar1, 50 * SK_Scalar1,
20 * SK_Scalar1, 100 * SK_Scalar1,
0 * SK_Scalar1, 0 * SK_Scalar1);
// path that has a cubic with a repeated first control point and
// a repeated last control point.
fPaths.push_back().moveTo(SK_Scalar1 * 10, SK_Scalar1 * 10);
fPaths.back().cubicTo(10 * SK_Scalar1, 10 * SK_Scalar1,
10 * SK_Scalar1, 0,
20 * SK_Scalar1, 0);
fPaths.back().lineTo(40 * SK_Scalar1, 0);
fPaths.back().cubicTo(40 * SK_Scalar1, 0,
50 * SK_Scalar1, 0,
50 * SK_Scalar1, 10 * SK_Scalar1);
// path that has two cubics with repeated middle control points.
fPaths.push_back().moveTo(SK_Scalar1 * 10, SK_Scalar1 * 10);
fPaths.back().cubicTo(10 * SK_Scalar1, 0,
10 * SK_Scalar1, 0,
20 * SK_Scalar1, 0);
fPaths.back().lineTo(40 * SK_Scalar1, 0);
fPaths.back().cubicTo(50 * SK_Scalar1, 0,
50 * SK_Scalar1, 0,
50 * SK_Scalar1, 10 * SK_Scalar1);
// triangle where one edge is a degenerate quad
fPaths.push_back().moveTo(SkFloatToScalar(8.59375f), 45 * SK_Scalar1);
fPaths.back().quadTo(SkFloatToScalar(16.9921875f), 45 * SK_Scalar1,
SkFloatToScalar(31.25f), 45 * SK_Scalar1);
fPaths.back().lineTo(100 * SK_Scalar1, 100 * SK_Scalar1);
fPaths.back().lineTo(SkFloatToScalar(8.59375f), 45 * SK_Scalar1);
// point degenerate
fPaths.push_back().moveTo(50 * SK_Scalar1, 50 * SK_Scalar1);
fPaths.back().lineTo(50 * SK_Scalar1, 50 * SK_Scalar1);
fPaths.push_back().moveTo(50 * SK_Scalar1, 50 * SK_Scalar1);
fPaths.back().quadTo(50 * SK_Scalar1, 50 * SK_Scalar1,
50 * SK_Scalar1, 50 * SK_Scalar1);
fPaths.push_back().moveTo(50 * SK_Scalar1, 50 * SK_Scalar1);
fPaths.back().cubicTo(50 * SK_Scalar1, 50 * SK_Scalar1,
50 * SK_Scalar1, 50 * SK_Scalar1,
50 * SK_Scalar1, 50 * SK_Scalar1);
// moveTo only paths
fPaths.push_back().moveTo(0, 0);
fPaths.back().moveTo(0, 0);
fPaths.back().moveTo(SK_Scalar1, SK_Scalar1);
fPaths.back().moveTo(SK_Scalar1, SK_Scalar1);
fPaths.back().moveTo(10 * SK_Scalar1, 10 * SK_Scalar1);
fPaths.push_back().moveTo(0, 0);
fPaths.back().moveTo(0, 0);
// line degenerate
fPaths.push_back().lineTo(100 * SK_Scalar1, 100 * SK_Scalar1);
fPaths.push_back().quadTo(100 * SK_Scalar1, 100 * SK_Scalar1, 0, 0);
fPaths.push_back().quadTo(100 * SK_Scalar1, 100 * SK_Scalar1,
50 * SK_Scalar1, 50 * SK_Scalar1);
fPaths.push_back().quadTo(50 * SK_Scalar1, 50 * SK_Scalar1,
100 * SK_Scalar1, 100 * SK_Scalar1);
fPaths.push_back().cubicTo(0, 0,
0, 0,
100 * SK_Scalar1, 100 * SK_Scalar1);
// small circle. This is listed last so that it has device coords far
// from the origin (small area relative to x,y values).
fPaths.push_back().addCircle(0, 0, SkFloatToScalar(0.8f));
}
virtual void onDraw(SkCanvas* canvas) {
this->makePaths();
SkPaint paint;
paint.setAntiAlias(true);
SkRandom rand;
canvas->translate(20 * SK_Scalar1, 20 * SK_Scalar1);
for (int i = 0; i < fPaths.count(); ++i) {
canvas->save();
// position the path, and make it at off-integer coords.
canvas->translate(SK_Scalar1 * 200 * (i % 5) + SK_Scalar1 / 4,
SK_Scalar1 * 200 * (i / 5) + 3 * SK_Scalar1 / 4);
SkColor color = rand.nextU();
color |= 0xff000000;
paint.setColor(color);
SkASSERT(fPaths[i].isConvex());
canvas->drawPath(fPaths[i], paint);
canvas->restore();
}
}
private:
typedef GM INHERITED;
SkTArray<SkPath> fPaths;
};
//////////////////////////////////////////////////////////////////////////////
static GM* MyFactory(void*) { return new ConvexPathsGM; }
static GMRegistry reg(MyFactory);
}