tests/ImageFilterTest.cpp

/*
 * 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 "Test.h"
#include "TestClassDef.h"
#include "SkBicubicImageFilter.h"
#include "SkBitmap.h"
#include "SkBitmapDevice.h"
#include "SkBitmapSource.h"
#include "SkCanvas.h"
#include "SkColorMatrixFilter.h"
#include "SkColorFilterImageFilter.h"
#include "SkDeviceImageFilterProxy.h"
#include "SkLightingImageFilter.h"
#include "SkRect.h"

static const int kBitmapSize = 4;

static void make_small_bitmap(SkBitmap& bitmap) {
    bitmap.setConfig(SkBitmap::kARGB_8888_Config, kBitmapSize, kBitmapSize);
    bitmap.allocPixels();
    SkBitmapDevice device(bitmap);
    SkCanvas canvas(&device);
    canvas.clear(0x00000000);
    SkPaint darkPaint;
    darkPaint.setColor(0xFF804020);
    SkPaint lightPaint;
    lightPaint.setColor(0xFF244484);
    const int i = kBitmapSize / 4;
    for (int y = 0; y < kBitmapSize; y += i) {
        for (int x = 0; x < kBitmapSize; x += i) {
            canvas.save();
            canvas.translate(SkIntToScalar(x), SkIntToScalar(y));
            canvas.drawRect(SkRect::MakeXYWH(0, 0,
                                             SkIntToScalar(i),
                                             SkIntToScalar(i)), darkPaint);
            canvas.drawRect(SkRect::MakeXYWH(SkIntToScalar(i),
                                             0,
                                             SkIntToScalar(i),
                                             SkIntToScalar(i)), lightPaint);
            canvas.drawRect(SkRect::MakeXYWH(0,
                                             SkIntToScalar(i),
                                             SkIntToScalar(i),
                                             SkIntToScalar(i)), lightPaint);
            canvas.drawRect(SkRect::MakeXYWH(SkIntToScalar(i),
                                             SkIntToScalar(i),
                                             SkIntToScalar(i),
                                             SkIntToScalar(i)), darkPaint);
            canvas.restore();
        }
    }
}

static SkImageFilter* make_scale(float amount, SkImageFilter* input = NULL) {
    SkScalar s = amount;
    SkScalar matrix[20] = { s, 0, 0, 0, 0,
                            0, s, 0, 0, 0,
                            0, 0, s, 0, 0,
                            0, 0, 0, s, 0 };
    SkAutoTUnref<SkColorFilter> filter(new SkColorMatrixFilter(matrix));
    return SkColorFilterImageFilter::Create(filter, input);
}

static SkImageFilter* make_grayscale(SkImageFilter* input = NULL, const SkImageFilter::CropRect* cropRect = NULL) {
    SkScalar matrix[20];
    memset(matrix, 0, 20 * sizeof(SkScalar));
    matrix[0] = matrix[5] = matrix[10] = 0.2126f;
    matrix[1] = matrix[6] = matrix[11] = 0.7152f;
    matrix[2] = matrix[7] = matrix[12] = 0.0722f;
    matrix[18] = 1.0f;
    SkAutoTUnref<SkColorFilter> filter(new SkColorMatrixFilter(matrix));
    return SkColorFilterImageFilter::Create(filter, input, cropRect);
}

DEF_TEST(ImageFilter, reporter) {
    {
        // Check that two non-clipping color matrices concatenate into a single filter.
        SkAutoTUnref<SkImageFilter> halfBrightness(make_scale(0.5f));
        SkAutoTUnref<SkImageFilter> quarterBrightness(make_scale(0.5f, halfBrightness));
        REPORTER_ASSERT(reporter, NULL == quarterBrightness->getInput(0));
    }

    {
        // Check that a clipping color matrix followed by a grayscale does not concatenate into a single filter.
        SkAutoTUnref<SkImageFilter> doubleBrightness(make_scale(2.0f));
        SkAutoTUnref<SkImageFilter> halfBrightness(make_scale(0.5f, doubleBrightness));
        REPORTER_ASSERT(reporter, NULL != halfBrightness->getInput(0));
    }

    {
        // Check that a color filter image filter without a crop rect can be
        // expressed as a color filter.
        SkAutoTUnref<SkImageFilter> gray(make_grayscale());
        REPORTER_ASSERT(reporter, true == gray->asColorFilter(NULL));
    }

    {
        // Check that a color filter image filter with a crop rect cannot
        // be expressed as a color filter.
        SkImageFilter::CropRect cropRect(SkRect::MakeXYWH(0, 0, 100, 100));
        SkAutoTUnref<SkImageFilter> grayWithCrop(make_grayscale(NULL, &cropRect));
        REPORTER_ASSERT(reporter, false == grayWithCrop->asColorFilter(NULL));
    }

    {
        // Tests pass by not asserting
        SkBitmap bitmap, result;
        make_small_bitmap(bitmap);
        result.setConfig(SkBitmap::kARGB_8888_Config, kBitmapSize, kBitmapSize);
        result.allocPixels();

        {
            // This tests for :
            // 1 ) location at (0,0,1)
            SkPoint3 location(0, 0, SK_Scalar1);
            // 2 ) location and target at same value
            SkPoint3 target(location.fX, location.fY, location.fZ);
            // 3 ) large negative specular exponent value
            SkScalar specularExponent = -1000;

            SkAutoTUnref<SkImageFilter> bmSrc(new SkBitmapSource(bitmap));
            SkPaint paint;
            paint.setImageFilter(SkLightingImageFilter::CreateSpotLitSpecular(
                    location, target, specularExponent, 180,
                    0xFFFFFFFF, SK_Scalar1, SK_Scalar1, SK_Scalar1,
                    bmSrc))->unref();
            SkCanvas canvas(result);
            SkRect r = SkRect::MakeWH(SkIntToScalar(kBitmapSize),
                                      SkIntToScalar(kBitmapSize));
            canvas.drawRect(r, paint);
        }

        {
            // This tests for scale bringing width to 0
            SkSize scale = SkSize::Make(-0.001f, SK_Scalar1);
            SkAutoTUnref<SkImageFilter> bmSrc(new SkBitmapSource(bitmap));
            SkAutoTUnref<SkBicubicImageFilter> bicubic(
                SkBicubicImageFilter::CreateMitchell(scale, bmSrc));
            SkBitmapDevice device(bitmap);
            SkDeviceImageFilterProxy proxy(&device);
            SkIPoint loc = SkIPoint::Make(0, 0);
            // An empty input should early return and return false
            REPORTER_ASSERT(reporter,
                            !bicubic->filterImage(&proxy, bitmap, SkMatrix::I(), &result, &loc));
        }
    }
}