tests/PictureTest.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 "Test.h"
#include "SkCanvas.h"
#include "SkColorPriv.h"
#include "SkData.h"
#include "SkPaint.h"
#include "SkPicture.h"
#include "SkRandom.h"
#include "SkShader.h"
#include "SkStream.h"

#include "SkPictureUtils.h"

static void make_bm(SkBitmap* bm, int w, int h, SkColor color, bool immutable) {
    bm->setConfig(SkBitmap::kARGB_8888_Config, w, h);
    bm->allocPixels();
    bm->eraseColor(color);
    if (immutable) {
        bm->setImmutable();
    }
}

typedef void (*DrawBitmapProc)(SkCanvas*, const SkBitmap&, const SkPoint&);

static void drawbitmap_proc(SkCanvas* canvas, const SkBitmap& bm,
                            const SkPoint& pos) {
    canvas->drawBitmap(bm, pos.fX, pos.fY, NULL);
}

static void drawbitmaprect_proc(SkCanvas* canvas, const SkBitmap& bm,
                                const SkPoint& pos) {
    SkRect r = {
        0, 0, SkIntToScalar(bm.width()), SkIntToScalar(bm.height())
    };
    r.offset(pos.fX, pos.fY);
    canvas->drawBitmapRectToRect(bm, NULL, r, NULL);
}

static void drawshader_proc(SkCanvas* canvas, const SkBitmap& bm,
                            const SkPoint& pos) {
    SkRect r = {
        0, 0, SkIntToScalar(bm.width()), SkIntToScalar(bm.height())
    };
    r.offset(pos.fX, pos.fY);

    SkShader* s = SkShader::CreateBitmapShader(bm,
                                               SkShader::kClamp_TileMode,
                                               SkShader::kClamp_TileMode);
    SkPaint paint;
    paint.setShader(s)->unref();
    canvas->drawRect(r, paint);
}

// Return a picture with the bitmaps drawn at the specified positions.
static SkPicture* record_bitmaps(const SkBitmap bm[], const SkPoint pos[],
                                 int count, DrawBitmapProc proc) {
    SkPicture* pic = new SkPicture;
    SkCanvas* canvas = pic->beginRecording(1000, 1000);
    for (int i = 0; i < count; ++i) {
        proc(canvas, bm[i], pos[i]);
    }
    pic->endRecording();
    return pic;
}

static void rand_rect(SkRect* rect, SkRandom& rand, SkScalar W, SkScalar H) {
    rect->fLeft   = rand.nextRangeScalar(-W, 2*W);
    rect->fTop    = rand.nextRangeScalar(-H, 2*H);
    rect->fRight  = rect->fLeft + rand.nextRangeScalar(0, W);
    rect->fBottom = rect->fTop + rand.nextRangeScalar(0, H);

    // we integralize rect to make our tests more predictable, since Gather is
    // a little sloppy.
    SkIRect ir;
    rect->round(&ir);
    rect->set(ir);
}

// Allocate result to be large enough to hold subset, and then draw the picture
// into it, offsetting by subset's top/left corner.
static void draw(SkPicture* pic, const SkRect& subset, SkBitmap* result) {
    SkIRect ir;
    subset.roundOut(&ir);
    int w = ir.width();
    int h = ir.height();
    make_bm(result, w, h, 0, false);

    SkCanvas canvas(*result);
    canvas.translate(-SkIntToScalar(ir.left()), -SkIntToScalar(ir.top()));
    canvas.drawPicture(*pic);
}

template <typename T> int find_index(const T* array, T elem, int count) {
    for (int i = 0; i < count; ++i) {
        if (array[i] == elem) {
            return i;
        }
    }
    return -1;
}

// Return true if 'ref' is found in array[]
static bool find(SkPixelRef const * const * array, SkPixelRef const * ref, int count) {
    return find_index<const SkPixelRef*>(array, ref, count) >= 0;
}

// Look at each pixel in bm, and if its color appears in colors[], find the
// corresponding value in refs[] and append that ref into array, skipping
// duplicates of the same value.
static void gather_from_colors(const SkBitmap& bm, SkPixelRef* const refs[],
                               int count, SkTDArray<SkPixelRef*>* array) {
    // Since we only want to return unique values in array, when we scan we just
    // set a bit for each index'd color found. In practice we only have a few
    // distinct colors, so we just use an int's bits as our array. Hence the
    // assert that count <= number-of-bits-in-our-int.
    SkASSERT((unsigned)count <= 32);
    uint32_t bitarray = 0;

    SkAutoLockPixels alp(bm);

    for (int y = 0; y < bm.height(); ++y) {
        for (int x = 0; x < bm.width(); ++x) {
            SkPMColor pmc = *bm.getAddr32(x, y);
            // the only good case where the color is not found would be if
            // the color is transparent, meaning no bitmap was drawn in that
            // pixel.
            if (pmc) {
                int index = SkGetPackedR32(pmc);
                SkASSERT(SkGetPackedG32(pmc) == index);
                SkASSERT(SkGetPackedB32(pmc) == index);
                SkASSERT(index < count);
                bitarray |= 1 << index;
            }
        }
    }

    for (int i = 0; i < count; ++i) {
        if (bitarray & (1 << i)) {
            *array->append() = refs[i];
        }
    }
}

static void test_gatherpixelrefs(skiatest::Reporter* reporter) {
    const int IW = 8;
    const int IH = IW;
    const SkScalar W = SkIntToScalar(IW);
    const SkScalar H = W;

    static const int N = 4;
    SkBitmap bm[N];
    SkPMColor pmcolors[N];
    SkPixelRef* refs[N];

    const SkPoint pos[] = {
        { 0, 0 }, { W, 0 }, { 0, H }, { W, H }
    };

    // Our convention is that the color components contain the index of their
    // corresponding bitmap/pixelref
    for (int i = 0; i < N; ++i) {
        make_bm(&bm[i], IW, IH, SkColorSetARGB(0xFF, i, i, i), true);
        refs[i] = bm[i].pixelRef();
    }

    static const DrawBitmapProc procs[] = {
        drawbitmap_proc, drawbitmaprect_proc, drawshader_proc
    };

    SkRandom rand;
    for (size_t k = 0; k < SK_ARRAY_COUNT(procs); ++k) {
        SkAutoTUnref<SkPicture> pic(record_bitmaps(bm, pos, N, procs[k]));

        // quick check for a small piece of each quadrant, which should just
        // contain 1 bitmap.
        for (size_t  i = 0; i < SK_ARRAY_COUNT(pos); ++i) {
            SkRect r;
            r.set(2, 2, W - 2, H - 2);
            r.offset(pos[i].fX, pos[i].fY);
            SkAutoDataUnref data(SkPictureUtils::GatherPixelRefs(pic, r));
            REPORTER_ASSERT(reporter, data);
            int count = data->size() / sizeof(SkPixelRef*);
            REPORTER_ASSERT(reporter, 1 == count);
            REPORTER_ASSERT(reporter, *(SkPixelRef**)data->data() == refs[i]);
        }

        // Test a bunch of random (mostly) rects, and compare the gather results
        // with a deduced list of refs by looking at the colors drawn.
        for (int j = 0; j < 100; ++j) {
            SkRect r;
            rand_rect(&r, rand, 2*W, 2*H);

            SkBitmap result;
            draw(pic, r, &result);
            SkTDArray<SkPixelRef*> array;

            SkData* data = SkPictureUtils::GatherPixelRefs(pic, r);
            size_t dataSize = data ? data->size() : 0;
            int gatherCount = dataSize / sizeof(SkPixelRef*);
            SkASSERT(gatherCount * sizeof(SkPixelRef*) == dataSize);
            SkPixelRef** gatherRefs = data ? (SkPixelRef**)(data->data()) : NULL;
            SkAutoDataUnref adu(data);

            gather_from_colors(result, refs, N, &array);

            /*
             *  GatherPixelRefs is conservative, so it can return more bitmaps
             *  that we actually can see (usually because of conservative bounds
             *  inflation for antialiasing). Thus our check here is only that
             *  Gather didn't miss any that we actually saw. Even that isn't
             *  a strict requirement on Gather, which is meant to be quick and
             *  only mostly-correct, but at the moment this test should work.
             */
            for (int i = 0; i < array.count(); ++i) {
                bool found = find(gatherRefs, array[i], gatherCount);
                REPORTER_ASSERT(reporter, found);
#if 0
                // enable this block of code to debug failures, as it will rerun
                // the case that failed.
                if (!found) {
                    SkData* data = SkPictureUtils::GatherPixelRefs(pic, r);
                    size_t dataSize = data ? data->size() : 0;
                }
#endif
            }
        }
    }
}

#ifdef SK_DEBUG
// Ensure that deleting SkPicturePlayback does not assert. Asserts only fire in debug mode, so only
// run in debug mode.
static void test_deleting_empty_playback() {
    SkPicture picture;
    // Creates an SkPictureRecord
    picture.beginRecording(0, 0);
    // Turns that into an SkPicturePlayback
    picture.endRecording();
    // Deletes the old SkPicturePlayback, and creates a new SkPictureRecord
    picture.beginRecording(0, 0);
}

// Ensure that serializing an empty picture does not assert. Likewise only runs in debug mode.
static void test_serializing_empty_picture() {
    SkPicture picture;
    picture.beginRecording(0, 0);
    picture.endRecording();
    SkDynamicMemoryWStream stream;
    picture.serialize(&stream);
}
#endif

static void rand_op(SkCanvas* canvas, SkRandom& rand) {
    SkPaint paint;
    SkRect rect = SkRect::MakeWH(50, 50);

    SkScalar unit = rand.nextUScalar1();
    if (unit <= 0.3) {
//        SkDebugf("save\n");
        canvas->save();
    } else if (unit <= 0.6) {
//        SkDebugf("restore\n");
        canvas->restore();
    } else if (unit <= 0.9) {
//        SkDebugf("clip\n");
        canvas->clipRect(rect);
    } else {
//        SkDebugf("draw\n");
        canvas->drawPaint(paint);
    }
}

static void test_peephole(skiatest::Reporter* reporter) {
    SkRandom rand;

    for (int j = 0; j < 100; j++) {
        SkRandom rand2(rand.getSeed()); // remember the seed

        SkPicture picture;
        SkCanvas* canvas = picture.beginRecording(100, 100);

        for (int i = 0; i < 1000; ++i) {
            rand_op(canvas, rand);
        }
        picture.endRecording();
    }

    {
        SkPicture picture;
        SkCanvas* canvas = picture.beginRecording(100, 100);
        SkRect rect = SkRect::MakeWH(50, 50);

        for (int i = 0; i < 100; ++i) {
            canvas->save();
        }
        while (canvas->getSaveCount() > 1) {
            canvas->clipRect(rect);
            canvas->restore();
        }
        picture.endRecording();
    }
}

static void TestPicture(skiatest::Reporter* reporter) {
#ifdef SK_DEBUG
    test_deleting_empty_playback();
    test_serializing_empty_picture();
#endif
    test_peephole(reporter);
    test_gatherpixelrefs(reporter);
}

#include "TestClassDef.h"
DEFINE_TESTCLASS("Pictures", PictureTestClass, TestPicture)