gm/imagefilterstransformed.cpp

/*
 * Copyright 2015 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "sk_tool_utils.h"
#include "SkBitmapSource.h"
#include "SkBlurImageFilter.h"
#include "SkColor.h"
#include "SkDisplacementMapEffect.h"
#include "SkDropShadowImageFilter.h"
#include "SkGradientShader.h"
#include "SkMorphologyImageFilter.h"
#include "SkScalar.h"
#include "gm.h"

namespace skiagm {

// This GM draws image filters with a CTM containing shearing / rotation.
// It checks that the scale portion of the CTM is correctly extracted
// and applied to the image inputs separately from the non-scale portion.

class ImageFiltersTransformedGM : public GM {
public:
    ImageFiltersTransformedGM() {
        this->setBGColor(SK_ColorBLACK);
    }

protected:

    SkString onShortName() override { return SkString("imagefilterstransformed"); }

    SkISize onISize() override { return SkISize::Make(420, 240); }

    void makeGradientCircle(int width, int height) {
        SkScalar x = SkIntToScalar(width / 2);
        SkScalar y = SkIntToScalar(height / 2);
        SkScalar radius = SkMinScalar(x, y) * 0.8f;
        fGradientCircle.allocN32Pixels(width, height);
        SkCanvas canvas(fGradientCircle);
        canvas.clear(0x00000000);
        SkColor colors[2];
        colors[0] = SK_ColorWHITE;
        colors[1] = SK_ColorBLACK;
        SkAutoTUnref<SkShader> shader(
            SkGradientShader::CreateRadial(SkPoint::Make(x, y), radius, colors, NULL, 2,
                                           SkShader::kClamp_TileMode)
        );
        SkPaint paint;
        paint.setShader(shader);
        canvas.drawCircle(x, y, radius, paint);
    }

    void onOnceBeforeDraw() override {
        fCheckerboard.allocN32Pixels(64, 64);
        SkCanvas checkerboardCanvas(fCheckerboard);
        sk_tool_utils::draw_checkerboard(&checkerboardCanvas, 0xFFA0A0A0, 0xFF404040, 8);

        this->makeGradientCircle(64, 64);
    }

    void onDraw(SkCanvas* canvas) override {
        SkAutoTUnref<SkImageFilter> gradient(SkBitmapSource::Create(fGradientCircle));
        SkAutoTUnref<SkImageFilter> checkerboard(SkBitmapSource::Create(fCheckerboard));
        SkImageFilter* filters[] = {
            SkBlurImageFilter::Create(12, 0),
            SkDropShadowImageFilter::Create(0, 15, 8, 0, SK_ColorGREEN,
                SkDropShadowImageFilter::kDrawShadowAndForeground_ShadowMode),
            SkDisplacementMapEffect::Create(SkDisplacementMapEffect::kR_ChannelSelectorType,
                                            SkDisplacementMapEffect::kR_ChannelSelectorType,
                                            12,
                                            gradient.get(),
                                            checkerboard.get()),
            SkDilateImageFilter::Create(2, 2, checkerboard.get()),
            SkErodeImageFilter::Create(2, 2, checkerboard.get()),
        };

        const SkScalar margin = SkIntToScalar(20);
        const SkScalar size = SkIntToScalar(60);

        for (size_t j = 0; j < 3; j++) {
            canvas->save();
            canvas->translate(margin, 0);
            for (size_t i = 0; i < SK_ARRAY_COUNT(filters); ++i) {
                SkPaint paint;
                paint.setColor(SK_ColorWHITE);
                paint.setImageFilter(filters[i]);
                paint.setAntiAlias(true);
                canvas->save();
                canvas->translate(size * SK_ScalarHalf, size * SK_ScalarHalf);
                canvas->scale(SkDoubleToScalar(0.8), SkDoubleToScalar(0.8));
                if (j == 1) {
                    canvas->rotate(SkIntToScalar(45));
                } else if (j == 2) {
                    canvas->skew(SkDoubleToScalar(0.5), SkDoubleToScalar(0.2));
                }
                canvas->translate(-size * SK_ScalarHalf, -size * SK_ScalarHalf);
                canvas->drawOval(SkRect::MakeXYWH(0, size * SkDoubleToScalar(0.1),
                                                  size, size * SkDoubleToScalar(0.6)), paint);
                canvas->restore();
                canvas->translate(size + margin, 0);
            }
            canvas->restore();
            canvas->translate(0, size + margin);
        }

        for (size_t i = 0; i < SK_ARRAY_COUNT(filters); ++i) {
            SkSafeUnref(filters[i]);
        }
    }

private:
    SkBitmap fCheckerboard;
    SkBitmap fGradientCircle;
    typedef GM INHERITED;
};

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

DEF_GM( return new ImageFiltersTransformedGM; )

}