gm/strokerect.cpp

/*
 * Copyright 2012 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"

#define STROKE_WIDTH    SkIntToScalar(20)

static void draw_path(SkCanvas* canvas, const SkPath& path, const SkRect& rect, SkPaint::Join join) {
    SkPaint paint;
    paint.setAntiAlias(true);
    paint.setStyle(SkPaint::kStroke_Style);

    paint.setColor(SK_ColorGRAY);
    paint.setStrokeWidth(STROKE_WIDTH);
    paint.setStrokeJoin(join);
    canvas->drawRect(rect, paint);

    paint.setStrokeWidth(0);
    paint.setColor(SK_ColorRED);
    canvas->drawPath(path, paint);

    paint.setStrokeWidth(3);
    paint.setStrokeJoin(SkPaint::kMiter_Join);
    int n = path.countPoints();
    SkAutoTArray<SkPoint> points(n);
    path.getPoints(points.get(), n);
    canvas->drawPoints(SkCanvas::kPoints_PointMode, n, points.get(), paint);
}

/*
 *  Test calling SkStroker for rectangles. Cases to cover:
 *
 *  geometry: normal, small (smaller than stroke-width), empty, inverted
 *  joint-type for the corners
 */
class StrokeRectGM : public skiagm::GM {
public:
    StrokeRectGM() {}

protected:
    virtual SkString onShortName() {
        return SkString("strokerect");
    }

    virtual SkISize onISize() {
        return SkISize::Make(1024, 480);
    }

    virtual void onDraw(SkCanvas* canvas) {
        canvas->drawColor(SK_ColorWHITE);
        canvas->translate(STROKE_WIDTH*3/2, STROKE_WIDTH*3/2);

        SkPaint paint;
        paint.setStyle(SkPaint::kStroke_Style);
        paint.setStrokeWidth(STROKE_WIDTH);

        static const SkPaint::Join gJoins[] = {
            SkPaint::kMiter_Join, SkPaint::kRound_Join, SkPaint::kBevel_Join
        };

        static const SkScalar W = 80;
        static const SkScalar H = 110;
        static const SkRect gRects[] = {
            { 0, 0, W, H },
            { W, 0, 0, H },
            { 0, H, W, 0 },
            { 0, 0, STROKE_WIDTH, H },
            { 0, 0, W, STROKE_WIDTH },
            { 0, 0, STROKE_WIDTH/2, STROKE_WIDTH/2 },
            { 0, 0, W, 0 },
            { 0, 0, 0, H },
            { 0, 0, 0, 0 },
        };
            
        for (size_t i = 0; i < SK_ARRAY_COUNT(gJoins); ++i) {
            SkPaint::Join join = gJoins[i];
            paint.setStrokeJoin(join);

            SkAutoCanvasRestore acr(canvas, true);
            for (size_t j = 0; j < SK_ARRAY_COUNT(gRects); ++j) {
                const SkRect& r = gRects[j];

                SkPath path, fillPath;
                path.addRect(r);
                paint.getFillPath(path, &fillPath);
                draw_path(canvas, fillPath, r, join);

                canvas->translate(W + 2 * STROKE_WIDTH, 0);
            }
            acr.restore();
            canvas->translate(0, H + 2 * STROKE_WIDTH);
        }
    }

private:
    typedef GM INHERITED;
};

///////////////////////////////////////////////////////////////////////////////////////////////////

DEF_GM(return new StrokeRectGM;)