skia2/gm/polygons.cpp

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/*
* Copyright 2013 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 "SkCanvas.h"
#include "SkPath.h"
#include "SkRandom.h"
#include "SkScalar.h"
#include "SkTArray.h"
namespace skiagm {
// This GM tests a grab-bag of convex and concave polygons. They are triangles,
// trapezoid, diamond, polygons with lots of edges, several concave polygons...
// But rectangles are excluded.
class PolygonsGM: public GM {
public:
PolygonsGM() {}
protected:
virtual uint32_t onGetFlags() const SK_OVERRIDE {
return kSkipTiled_Flag;
}
virtual SkString onShortName() SK_OVERRIDE {
return SkString("polygons");
}
virtual SkISize onISize() SK_OVERRIDE {
int width = kNumPolygons * kCellSize + 40;
int height = (kNumJoins * kNumStrokeWidths + kNumExtraStyles) * kCellSize + 40;
return SkISize::Make(width, height);
}
// Construct all polygons
virtual void onOnceBeforeDraw() SK_OVERRIDE {
SkPoint p0[] = {{0, 0}, {60, 0}, {90, 40}}; // triangle
SkPoint p1[] = {{0, 0}, {0, 40}, {60, 40}, {40, 0}}; // trapezoid
SkPoint p2[] = {{0, 0}, {40, 40}, {80, 40}, {40, 0}}; // diamond
SkPoint p3[] = {{10, 0}, {50, 0}, {60, 10}, {60, 30}, {50, 40},
{10, 40}, {0, 30}, {0, 10}}; // octagon
SkPoint p4[32]; // circle-like polygons with 32-edges.
SkPoint p5[] = {{0, 0}, {20, 20}, {0, 40}, {60, 20}}; // concave polygon with 4 edges
SkPoint p6[] = {{0, 40}, {0, 30}, {15, 30}, {15, 20}, {30, 20},
{30, 10}, {45, 10}, {45, 0}, {60, 0}, {60, 40}}; // stairs-like polygon
SkPoint p7[] = {{0, 20}, {20, 20}, {30, 0}, {40, 20}, {60, 20},
{45, 30}, {55, 50}, {30, 40}, {5, 50}, {15, 30}}; // five-point stars
for (size_t i = 0; i < SK_ARRAY_COUNT(p4); ++i) {
SkScalar angle = 2 * SK_ScalarPI * i / SK_ARRAY_COUNT(p4);
p4[i].set(20 * SkScalarCos(angle) + 20, 20 * SkScalarSin(angle) + 20);
}
struct Polygons {
SkPoint* fPoints;
size_t fPointNum;
} pgs[] = {
{ p0, SK_ARRAY_COUNT(p0) },
{ p1, SK_ARRAY_COUNT(p1) },
{ p2, SK_ARRAY_COUNT(p2) },
{ p3, SK_ARRAY_COUNT(p3) },
{ p4, SK_ARRAY_COUNT(p4) },
{ p5, SK_ARRAY_COUNT(p5) },
{ p6, SK_ARRAY_COUNT(p6) },
{ p7, SK_ARRAY_COUNT(p7) }
};
SkASSERT(SK_ARRAY_COUNT(pgs) == kNumPolygons);
for (size_t pgIndex = 0; pgIndex < SK_ARRAY_COUNT(pgs); ++pgIndex) {
fPolygons.push_back().moveTo(pgs[pgIndex].fPoints[0].fX,
pgs[pgIndex].fPoints[0].fY);
for (size_t ptIndex = 1; ptIndex < pgs[pgIndex].fPointNum; ++ptIndex) {
fPolygons.back().lineTo(pgs[pgIndex].fPoints[ptIndex].fX,
pgs[pgIndex].fPoints[ptIndex].fY);
}
fPolygons.back().close();
}
}
// Set the location for the current test on the canvas
static void SetLocation(SkCanvas* canvas, int counter, int lineNum) {
SkScalar x = SK_Scalar1 * kCellSize * (counter % lineNum) + 30 + SK_Scalar1 / 4;
SkScalar y = SK_Scalar1 * kCellSize * (counter / lineNum) + 30 + 3 * SK_Scalar1 / 4;
canvas->translate(x, y);
}
static void SetColorAndAlpha(SkPaint* paint, SkRandom* rand) {
SkColor color = rand->nextU();
color |= 0xff000000;
paint->setColor(color);
if (40 == paint->getStrokeWidth()) {
paint->setAlpha(0xA0);
}
}
virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
// Stroke widths are:
// 0(may use hairline rendering), 10(common case for stroke-style)
// 40(>= geometry width/height, make the contour filled in fact)
static const int kStrokeWidths[] = {0, 10, 40};
SkASSERT(kNumStrokeWidths == SK_ARRAY_COUNT(kStrokeWidths));
static const SkPaint::Join kJoins[] = {
SkPaint::kMiter_Join, SkPaint::kRound_Join, SkPaint::kBevel_Join
};
SkASSERT(kNumJoins == SK_ARRAY_COUNT(kJoins));
int counter = 0;
SkPaint paint;
paint.setAntiAlias(true);
SkRandom rand;
// For stroke style painter
paint.setStyle(SkPaint::kStroke_Style);
for (int join = 0; join < kNumJoins; ++join) {
for (int width = 0; width < kNumStrokeWidths; ++width) {
for (int i = 0; i < fPolygons.count(); ++i) {
canvas->save();
SetLocation(canvas, counter, fPolygons.count());
SetColorAndAlpha(&paint, &rand);
paint.setStrokeJoin(kJoins[join]);
paint.setStrokeWidth(SkIntToScalar(kStrokeWidths[width]));
canvas->drawPath(fPolygons[i], paint);
canvas->restore();
++counter;
}
}
}
// For stroke-and-fill style painter and fill style painter
static const SkPaint::Style kStyles[] = {
SkPaint::kStrokeAndFill_Style, SkPaint::kFill_Style
};
SkASSERT(kNumExtraStyles == SK_ARRAY_COUNT(kStyles));
paint.setStrokeJoin(SkPaint::kMiter_Join);
paint.setStrokeWidth(SkIntToScalar(20));
for (int style = 0; style < kNumExtraStyles; ++style) {
paint.setStyle(kStyles[style]);
for (int i = 0; i < fPolygons.count(); ++i) {
canvas->save();
SetLocation(canvas, counter, fPolygons.count());
SetColorAndAlpha(&paint, &rand);
canvas->drawPath(fPolygons[i], paint);
canvas->restore();
++counter;
}
}
}
private:
static const int kNumPolygons = 8;
static const int kCellSize = 100;
static const int kNumExtraStyles = 2;
static const int kNumStrokeWidths = 3;
static const int kNumJoins = 3;
SkTArray<SkPath> fPolygons;
typedef GM INHERITED;
};
//////////////////////////////////////////////////////////////////////////////
DEF_GM(return new PolygonsGM;)
}