src/core/SkPicture.cpp

/*
 * Copyright 2007 The Android Open Source Project
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */


#include "SkPictureFlat.h"
#include "SkPictureData.h"
#include "SkPicturePlayback.h"
#include "SkPictureRecord.h"
#include "SkPictureRecorder.h"
#include "SkPictureStateTree.h"

#include "SkBitmapDevice.h"
#include "SkCanvas.h"
#include "SkChunkAlloc.h"
#include "SkDrawPictureCallback.h"
#include "SkPaintPriv.h"
#include "SkPathEffect.h"
#include "SkPicture.h"
#include "SkRegion.h"
#include "SkShader.h"
#include "SkStream.h"
#include "SkTDArray.h"
#include "SkTLogic.h"
#include "SkTSearch.h"
#include "SkTime.h"

#include "SkReader32.h"
#include "SkWriter32.h"
#include "SkRTree.h"
#include "SkBBoxHierarchyRecord.h"

#if SK_SUPPORT_GPU
#include "GrContext.h"
#endif

#include "SkRecord.h"
#include "SkRecordDraw.h"
#include "SkRecorder.h"

template <typename T> int SafeCount(const T* obj) {
    return obj ? obj->count() : 0;
}

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

namespace {

// Some commands have a paint, some have an optional paint.  Either way, get back a pointer.
static const SkPaint* AsPtr(const SkPaint& p) { return &p; }
static const SkPaint* AsPtr(const SkRecords::Optional<SkPaint>& p) { return p; }

/** SkRecords visitor to determine whether an instance may require an
    "external" bitmap to rasterize. May return false positives.
    Does not return true for bitmap text.

    Expected use is to determine whether images need to be decoded before
    rasterizing a particular SkRecord.
 */
struct BitmapTester {
    // Helpers.  These create HasMember_bitmap and HasMember_paint.
    SK_CREATE_MEMBER_DETECTOR(bitmap);
    SK_CREATE_MEMBER_DETECTOR(paint);


    // Main entry for visitor:
    // If the command has a bitmap directly, return true.
    // If the command has a paint and the paint has a bitmap, return true.
    // Otherwise, return false.
    template <typename T>
    bool operator()(const T& r) { return CheckBitmap(r); }


    // If the command has a bitmap, of course we're going to play back bitmaps.
    template <typename T>
    static SK_WHEN(HasMember_bitmap<T>, bool) CheckBitmap(const T&) { return true; }

    // If not, look for one in its paint (if it has a paint).
    template <typename T>
    static SK_WHEN(!HasMember_bitmap<T>, bool) CheckBitmap(const T& r) { return CheckPaint(r); }

    // If we have a paint, dig down into the effects looking for a bitmap.
    template <typename T>
    static SK_WHEN(HasMember_paint<T>, bool) CheckPaint(const T& r) {
        const SkPaint* paint = AsPtr(r.paint);
        if (paint) {
            const SkShader* shader = paint->getShader();
            if (shader &&
                shader->asABitmap(NULL, NULL, NULL) == SkShader::kDefault_BitmapType) {
                return true;
            }
        }
        return false;
    }

    // If we don't have a paint, that non-paint has no bitmap.
    template <typename T>
    static SK_WHEN(!HasMember_paint<T>, bool) CheckPaint(const T&) { return false; }
};

bool WillPlaybackBitmaps(const SkRecord& record) {
    BitmapTester tester;
    for (unsigned i = 0; i < record.count(); i++) {
        if (record.visit<bool>(i, tester)) {
            return true;
        }
    }
    return false;
}

/** SkRecords visitor to determine heuristically whether or not a SkPicture
    will be performant when rasterized on the GPU.
 */
struct PathCounter {
    SK_CREATE_MEMBER_DETECTOR(paint);

    PathCounter()
        : numPaintWithPathEffectUses (0)
        , numFastPathDashEffects (0)
        , numAAConcavePaths (0)
        , numAAHairlineConcavePaths (0) {
    }

    void checkPaint(const SkPaint* paint) {
        if (paint && paint->getPathEffect()) {
            numPaintWithPathEffectUses++;
        }
    }

    void operator()(const SkRecords::DrawPoints& op) {
        this->checkPaint(&op.paint);
        const SkPathEffect* effect = op.paint.getPathEffect();
        if (effect) {
            SkPathEffect::DashInfo info;
            SkPathEffect::DashType dashType = effect->asADash(&info);
            if (2 == op.count && SkPaint::kRound_Cap != op.paint.getStrokeCap() &&
                SkPathEffect::kDash_DashType == dashType && 2 == info.fCount) {
                numFastPathDashEffects++;
            }
        }
    }

    void operator()(const SkRecords::DrawPath& op) {
        this->checkPaint(&op.paint);
        if (op.paint.isAntiAlias() && !op.path.isConvex()) {
            numAAConcavePaths++;

            if (SkPaint::kStroke_Style == op.paint.getStyle() &&
                0 == op.paint.getStrokeWidth()) {
                numAAHairlineConcavePaths++;
            }
        }
    }

    template <typename T>
    SK_WHEN(HasMember_paint<T>, void) operator()(const T& op) {
        this->checkPaint(AsPtr(op.paint));
    }

    template <typename T>
    SK_WHEN(!HasMember_paint<T>, void) operator()(const T& op) { /* do nothing */ }


    int numPaintWithPathEffectUses;
    int numFastPathDashEffects;
    int numAAConcavePaths;
    int numAAHairlineConcavePaths;
};

bool SuitableForGpuRasterization(const SkRecord& record,
                                 const char** reason = NULL,
                                 int sampleCount = 0) {
    PathCounter counter;
    for (unsigned i = 0; i < record.count(); i++) {
        record.visit<void>(i, counter);
    }

    // TODO: the heuristic used here needs to be refined
    static const int kNumPaintWithPathEffectsUsesTol = 1;
    static const int kNumAAConcavePathsTol = 5;

    int numNonDashedPathEffects = counter.numPaintWithPathEffectUses -
                                  counter.numFastPathDashEffects;
    bool suitableForDash = (0 == counter.numPaintWithPathEffectUses) ||
                           (numNonDashedPathEffects < kNumPaintWithPathEffectsUsesTol
                               && 0 == sampleCount);

    bool ret = suitableForDash &&
               (counter.numAAConcavePaths - counter.numAAHairlineConcavePaths)
                   < kNumAAConcavePathsTol;

    if (!ret && NULL != reason) {
        if (!suitableForDash) {
            if (0 != sampleCount) {
                *reason = "Can't use multisample on dash effect.";
            } else {
                *reason = "Too many non dashed path effects.";
            }
        } else if ((counter.numAAConcavePaths - counter.numAAHairlineConcavePaths)
                    >= kNumAAConcavePathsTol)
            *reason = "Too many anti-aliased concave paths.";
        else
            *reason = "Unknown reason for GPU unsuitability.";
    }
    return ret;
}

} // namespace

SkPicture::Analysis::Analysis(const SkRecord& record)
    : fWillPlaybackBitmaps (WillPlaybackBitmaps(record))
    , fSuitableForGpuRasterization (SuitableForGpuRasterization(record)) { }

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

#ifdef SK_SUPPORT_LEGACY_DEFAULT_PICTURE_CTOR
// fRecord OK
SkPicture::SkPicture()
    : fWidth(0)
    , fHeight(0) {
    this->needsNewGenID();
}
#endif

// fRecord OK
SkPicture::SkPicture(int width, int height,
                     const SkPictureRecord& record,
                     bool deepCopyOps)
    : fWidth(width)
    , fHeight(height) {
    this->needsNewGenID();

    SkPictInfo info;
    this->createHeader(&info);
    fData.reset(SkNEW_ARGS(SkPictureData, (record, info, deepCopyOps)));
}

// Create an SkPictureData-backed SkPicture from an SkRecord.
// This for compatibility with serialization code only.  This is not cheap.
static SkPicture* backport(const SkRecord& src, int width, int height) {
    SkPictureRecorder recorder;
    SkRecordDraw(src, recorder.beginRecording(width, height), NULL/*bbh*/, NULL/*callback*/);
    return recorder.endRecording();
}

// fRecord OK
SkPicture::~SkPicture() {
    this->callDeletionListeners();
}

#ifdef SK_SUPPORT_LEGACY_PICTURE_CLONE
// fRecord TODO, fix by deleting this method
SkPicture* SkPicture::clone() const {
#ifdef SK_PICTURE_CLONE_NOOP
    return SkRef(const_cast<SkPicture*>(this));
#else
    SkAutoTDelete<SkPictureData> newData;

    if (fData.get()) {
        SkPictCopyInfo copyInfo;

        int paintCount = SafeCount(fData->fPaints);

        /* The alternative to doing this is to have a clone method on the paint and have it
         * make the deep copy of its internal structures as needed. The holdup to doing
         * that is at this point we would need to pass the SkBitmapHeap so that we don't
         * unnecessarily flatten the pixels in a bitmap shader.
         */
        copyInfo.paintData.setCount(paintCount);

        /* Use an SkBitmapHeap to avoid flattening bitmaps in shaders. If there already is
         * one, use it. If this SkPictureData was created from a stream, fBitmapHeap
         * will be NULL, so create a new one.
         */
        if (fData->fBitmapHeap.get() == NULL) {
            // FIXME: Put this on the stack inside SkPicture::clone.
            SkBitmapHeap* heap = SkNEW(SkBitmapHeap);
            copyInfo.controller.setBitmapStorage(heap);
            heap->unref();
        } else {
            copyInfo.controller.setBitmapStorage(fData->fBitmapHeap);
        }

        SkDEBUGCODE(int heapSize = SafeCount(fData->fBitmapHeap.get());)
        for (int i = 0; i < paintCount; i++) {
            if (NeedsDeepCopy(fData->fPaints->at(i))) {
                copyInfo.paintData[i] =
                    SkFlatData::Create<SkPaint::FlatteningTraits>(&copyInfo.controller,
                    fData->fPaints->at(i), 0);

            } else {
                // this is our sentinel, which we use in the unflatten loop
                copyInfo.paintData[i] = NULL;
            }
        }
        SkASSERT(SafeCount(fData->fBitmapHeap.get()) == heapSize);

        // needed to create typeface playback
        copyInfo.controller.setupPlaybacks();

        newData.reset(SkNEW_ARGS(SkPictureData, (*fData, &copyInfo)));
    }

    SkPicture* clone = SkNEW_ARGS(SkPicture, (newData.detach(), fWidth, fHeight));
    clone->fUniqueID = this->uniqueID(); // need to call method to ensure != 0

    return clone;
#endif
}
#endif//SK_SUPPORT_LEGACY_PICTURE_CLONE

// fRecord OK
void SkPicture::EXPERIMENTAL_addAccelData(const SkPicture::AccelData* data) const {
    fAccelData.reset(SkRef(data));
}

// fRecord OK
const SkPicture::AccelData* SkPicture::EXPERIMENTAL_getAccelData(
        SkPicture::AccelData::Key key) const {
    if (NULL != fAccelData.get() && fAccelData->getKey() == key) {
        return fAccelData.get();
    }
    return NULL;
}

// fRecord OK
SkPicture::AccelData::Domain SkPicture::AccelData::GenerateDomain() {
    static int32_t gNextID = 0;

    int32_t id = sk_atomic_inc(&gNextID);
    if (id >= 1 << (8 * sizeof(Domain))) {
        SK_CRASH();
    }

    return static_cast<Domain>(id);
}

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

uint32_t SkPicture::OperationList::offset(int index) const {
    SkASSERT(index < fOps.count());
    return ((SkPictureStateTree::Draw*)fOps[index])->fOffset;
}

const SkMatrix& SkPicture::OperationList::matrix(int index) const {
    SkASSERT(index < fOps.count());
    return *((SkPictureStateTree::Draw*)fOps[index])->fMatrix;
}

// fRecord TODO
const SkPicture::OperationList* SkPicture::EXPERIMENTAL_getActiveOps(const SkIRect& queryRect) const {
    SkASSERT(NULL != fData.get());
    if (NULL != fData.get()) {
        return fData->getActiveOps(queryRect);
    }
    return NULL;
}

// fRecord OK
void SkPicture::draw(SkCanvas* canvas, SkDrawPictureCallback* callback) const {
    SkASSERT(NULL != canvas);
    SkASSERT(NULL != fData.get() || NULL != fRecord.get());

    // If the query contains the whole picture, don't bother with the BBH.
    SkRect clipBounds = { 0, 0, 0, 0 };
    (void)canvas->getClipBounds(&clipBounds);
    const bool useBBH = !clipBounds.contains(SkRect::MakeWH(this->width(), this->height()));

    if (NULL != fData.get()) {
        SkPicturePlayback playback(this);
        playback.setUseBBH(useBBH);
        playback.draw(canvas, callback);
    }
    if (NULL != fRecord.get()) {
        SkRecordDraw(*fRecord, canvas, useBBH ? fBBH.get() : NULL, callback);
    }
}

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

#include "SkStream.h"

static const char kMagic[] = { 's', 'k', 'i', 'a', 'p', 'i', 'c', 't' };

// fRecord OK
bool SkPicture::IsValidPictInfo(const SkPictInfo& info) {
    if (0 != memcmp(info.fMagic, kMagic, sizeof(kMagic))) {
        return false;
    }

    if (info.fVersion < MIN_PICTURE_VERSION ||
        info.fVersion > CURRENT_PICTURE_VERSION) {
        return false;
    }

    return true;
}

// fRecord OK
bool SkPicture::InternalOnly_StreamIsSKP(SkStream* stream, SkPictInfo* pInfo) {
    if (NULL == stream) {
        return false;
    }

    // Check magic bytes.
    SkPictInfo info;
    SkASSERT(sizeof(kMagic) == sizeof(info.fMagic));
    if (!stream->read(&info, sizeof(info)) || !IsValidPictInfo(info)) {
        return false;
    }

    if (pInfo != NULL) {
        *pInfo = info;
    }
    return true;
}

// fRecord OK
bool SkPicture::InternalOnly_BufferIsSKP(SkReadBuffer& buffer, SkPictInfo* pInfo) {
    // Check magic bytes.
    SkPictInfo info;
    SkASSERT(sizeof(kMagic) == sizeof(info.fMagic));
    if (!buffer.readByteArray(&info, sizeof(info)) || !IsValidPictInfo(info)) {
        return false;
    }

    if (pInfo != NULL) {
        *pInfo = info;
    }
    return true;
}

// fRecord OK
SkPicture::SkPicture(SkPictureData* data, int width, int height)
    : fData(data)
    , fWidth(width)
    , fHeight(height) {
    this->needsNewGenID();
}

// fRecord OK
SkPicture* SkPicture::CreateFromStream(SkStream* stream, InstallPixelRefProc proc) {
    SkPictInfo info;

    if (!InternalOnly_StreamIsSKP(stream, &info)) {
        return NULL;
    }

    // Check to see if there is a playback to recreate.
    if (stream->readBool()) {
        SkPictureData* data = SkPictureData::CreateFromStream(stream, info, proc);
        if (NULL == data) {
            return NULL;
        }

        return SkNEW_ARGS(SkPicture, (data, info.fWidth, info.fHeight));
    }

    return NULL;
}

// fRecord OK
SkPicture* SkPicture::CreateFromBuffer(SkReadBuffer& buffer) {
    SkPictInfo info;

    if (!InternalOnly_BufferIsSKP(buffer, &info)) {
        return NULL;
    }

    // Check to see if there is a playback to recreate.
    if (buffer.readBool()) {
        SkPictureData* data = SkPictureData::CreateFromBuffer(buffer, info);
        if (NULL == data) {
            return NULL;
        }

        return SkNEW_ARGS(SkPicture, (data, info.fWidth, info.fHeight));
    }

    return NULL;
}

// fRecord OK
void SkPicture::createHeader(SkPictInfo* info) const {
    // Copy magic bytes at the beginning of the header
    SkASSERT(sizeof(kMagic) == 8);
    SkASSERT(sizeof(kMagic) == sizeof(info->fMagic));
    memcpy(info->fMagic, kMagic, sizeof(kMagic));

    // Set picture info after magic bytes in the header
    info->fVersion = CURRENT_PICTURE_VERSION;
    info->fWidth = fWidth;
    info->fHeight = fHeight;
    info->fFlags = SkPictInfo::kCrossProcess_Flag;
    // TODO: remove this flag, since we're always float (now)
    info->fFlags |= SkPictInfo::kScalarIsFloat_Flag;

    if (8 == sizeof(void*)) {
        info->fFlags |= SkPictInfo::kPtrIs64Bit_Flag;
    }
}

// fRecord OK
void SkPicture::serialize(SkWStream* stream, EncodeBitmap encoder) const {
    const SkPictureData* data = fData.get();

    // If we're a new-format picture, backport to old format for serialization.
    SkAutoTDelete<SkPicture> oldFormat;
    if (NULL == data && NULL != fRecord.get()) {
        oldFormat.reset(backport(*fRecord, fWidth, fHeight));
        data = oldFormat->fData.get();
        SkASSERT(NULL != data);
    }

    SkPictInfo info;
    this->createHeader(&info);
    stream->write(&info, sizeof(info));

    if (NULL != data) {
        stream->writeBool(true);
        data->serialize(stream, encoder);
    } else {
        stream->writeBool(false);
    }
}

// fRecord OK
void SkPicture::flatten(SkWriteBuffer& buffer) const {
    const SkPictureData* data = fData.get();

    // If we're a new-format picture, backport to old format for serialization.
    SkAutoTDelete<SkPicture> oldFormat;
    if (NULL == data && NULL != fRecord.get()) {
        oldFormat.reset(backport(*fRecord, fWidth, fHeight));
        data = oldFormat->fData.get();
        SkASSERT(NULL != data);
    }

    SkPictInfo info;
    this->createHeader(&info);
    buffer.writeByteArray(&info, sizeof(info));

    if (NULL != data) {
        buffer.writeBool(true);
        data->flatten(buffer);
    } else {
        buffer.writeBool(false);
    }
}

#if SK_SUPPORT_GPU
// fRecord OK
bool SkPicture::suitableForGpuRasterization(GrContext* context, const char **reason) const {
    if (fRecord.get()) {
        return fAnalysis.fSuitableForGpuRasterization;
    }
    if (NULL == fData.get()) {
        if (NULL != reason) {
            *reason = "Missing internal data.";
        }
        return false;
    }

    return fData->suitableForGpuRasterization(context, reason);
}
#endif

// fRecord TODO
bool SkPicture::hasText() const {
    return fData.get() && fData->hasText();
}

// fRecord OK
bool SkPicture::willPlayBackBitmaps() const {
    if (fRecord.get()) {
        return fAnalysis.fWillPlaybackBitmaps;
    }
    if (!fData.get()) {
        return false;
    }
    return fData->containsBitmaps();
}

// fRecord OK
static int32_t next_picture_generation_id() {
    static int32_t  gPictureGenerationID = 0;
    // do a loop in case our global wraps around, as we never want to
    // return a 0
    int32_t genID;
    do {
        genID = sk_atomic_inc(&gPictureGenerationID) + 1;
    } while (SK_InvalidGenID == genID);
    return genID;
}

// fRecord OK
uint32_t SkPicture::uniqueID() const {
    if (SK_InvalidGenID == fUniqueID) {
        fUniqueID = next_picture_generation_id();
    }
    return fUniqueID;
}

// fRecord OK
SkPicture::SkPicture(int width, int height, SkRecord* record, SkBBoxHierarchy* bbh)
    : fWidth(width)
    , fHeight(height)
    , fRecord(record)
    , fBBH(SkSafeRef(bbh))
    , fAnalysis(*record) {
    // TODO: delay as much of this work until just before first playback?
    if (fBBH.get()) {
        SkRecordFillBounds(*record, fBBH.get());
    }
    this->needsNewGenID();
}

// Note that we are assuming that this entry point will only be called from
// one thread. Currently the only client of this method is
// SkGpuDevice::EXPERIMENTAL_optimize which should be only called from a single
// thread.
void SkPicture::addDeletionListener(DeletionListener* listener) const {
    SkASSERT(NULL != listener);

    *fDeletionListeners.append() = SkRef(listener);
}

void SkPicture::callDeletionListeners() {
    for (int i = 0; i < fDeletionListeners.count(); ++i) {
        fDeletionListeners[i]->onDeletion(this->uniqueID());
    }

    fDeletionListeners.unrefAll();
}

// fRecord OK
int SkPicture::approximateOpCount() const {
    SkASSERT(fRecord.get() || fData.get());
    if (fRecord.get()) {
        return fRecord->count();
    }
    if (fData.get()) {
        return fData->opCount();
    }
    return 0;
}