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 "SkBitmapDevice.h"
#include "SkCanvas.h"
#include "SkChunkAlloc.h"
#include "SkMessageBus.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"

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

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

DECLARE_SKMESSAGEBUS_MESSAGE(SkPicture::DeletionMessage);

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

static int32_t gPictureGenerationID;

// never returns a 0
static int32_t next_picture_generation_id() {
    // Loop in case our global wraps around.
    int32_t genID;
    do {
        genID = sk_atomic_inc(&gPictureGenerationID) + 1;
    } while (0 == genID);
    return genID;
}

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

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 is a DrawPicture, recurse.
    // 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.
    bool operator()(const SkRecords::DrawPicture& op) { return op.picture->willPlayBackBitmaps(); }

    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;
}

// SkRecord visitor to find recorded text.
struct TextHunter {
    // All ops with text have that text as a char array member named "text".
    SK_CREATE_MEMBER_DETECTOR(text);
    bool operator()(const SkRecords::DrawPicture& op) { return op.picture->hasText(); }
    template <typename T> SK_WHEN(HasMember_text<T>,  bool) operator()(const T&) { return true;  }
    template <typename T> SK_WHEN(!HasMember_text<T>, bool) operator()(const T&) { return false; }
};

} // namespace

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

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

    // Recurse into nested pictures.
    void operator()(const SkRecords::DrawPicture& op) {
        const SkPicture::Analysis& analysis = op.picture->fAnalysis;
        numPaintWithPathEffectUses += analysis.fNumPaintWithPathEffectUses;
        numFastPathDashEffects     += analysis.fNumFastPathDashEffects;
        numAAConcavePaths          += analysis.fNumAAConcavePaths;
        numAAHairlineConcavePaths  += analysis.fNumAAHairlineConcavePaths;
        numAADFEligibleConcavePaths  += analysis.fNumAADFEligibleConcavePaths;
    }

    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++;

            SkPaint::Style paintStyle = op.paint.getStyle();
            const SkRect& pathBounds = op.path.getBounds();
            if (SkPaint::kStroke_Style == paintStyle &&
                0 == op.paint.getStrokeWidth()) {
                numAAHairlineConcavePaths++;
            } else if (SkPaint::kFill_Style == paintStyle && pathBounds.width() < 64.f &&
                       pathBounds.height() < 64.f && !op.path.isVolatile()) {
                numAADFEligibleConcavePaths++;
            }
        }
    }

    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;
    int numAADFEligibleConcavePaths;
};

SkPicture::Analysis::Analysis(const SkRecord& record) {
    fWillPlaybackBitmaps = WillPlaybackBitmaps(record);

    PathCounter counter;
    for (unsigned i = 0; i < record.count(); i++) {
        record.visit<void>(i, counter);
    }
    fNumPaintWithPathEffectUses = counter.numPaintWithPathEffectUses;
    fNumFastPathDashEffects     = counter.numFastPathDashEffects;
    fNumAAConcavePaths          = counter.numAAConcavePaths;
    fNumAAHairlineConcavePaths  = counter.numAAHairlineConcavePaths;
    fNumAADFEligibleConcavePaths  = counter.numAADFEligibleConcavePaths;

    fHasText = false;
    TextHunter text;
    for (unsigned i = 0; i < record.count(); i++) {
        if (record.visit<bool>(i, text)) {
            fHasText = true;
            break;
        }
    }
}

bool SkPicture::Analysis::suitableForGpuRasterization(const char** reason,
                                                      int sampleCount) const {
    // TODO: the heuristic used here needs to be refined
    static const int kNumPaintWithPathEffectsUsesTol = 1;
    static const int kNumAAConcavePathsTol = 5;

    int numNonDashedPathEffects = fNumPaintWithPathEffectUses -
                                  fNumFastPathDashEffects;
    bool suitableForDash = (0 == fNumPaintWithPathEffectUses) ||
                           (numNonDashedPathEffects < kNumPaintWithPathEffectsUsesTol
                               && 0 == sampleCount);

    bool ret = suitableForDash &&
               (fNumAAConcavePaths - fNumAAHairlineConcavePaths - fNumAADFEligibleConcavePaths)
                   < kNumAAConcavePathsTol;

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

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

int SkPicture::drawableCount() const {
    return fDrawablePicts.get() ? fDrawablePicts->count() : 0;
}

SkPicture const* const* SkPicture::drawablePicts() const {
    return fDrawablePicts.get() ? fDrawablePicts->begin() : NULL;
}

SkPicture::~SkPicture() {
    SkPicture::DeletionMessage msg;
    msg.fUniqueID = this->uniqueID();
    SkMessageBus<SkPicture::DeletionMessage>::Post(msg);
}

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

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

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);
}

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

void SkPicture::playback(SkCanvas* canvas, AbortCallback* callback) const {
    SkASSERT(canvas);

    // 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(this->cullRect());

    SkRecordDraw(*fRecord, canvas, this->drawablePicts(), NULL, this->drawableCount(),
                 useBBH ? fBBH.get() : NULL, callback);
}

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

#include "SkStream.h"

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

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;
}

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.fMagic, sizeof(kMagic))) {
        return false;
    }

    info.fVersion = stream->readU32();
    info.fCullRect.fLeft = stream->readScalar();
    info.fCullRect.fTop = stream->readScalar();
    info.fCullRect.fRight = stream->readScalar();
    info.fCullRect.fBottom = stream->readScalar();

    info.fFlags = stream->readU32();

    if (!IsValidPictInfo(info)) {
        return false;
    }

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

bool SkPicture::InternalOnly_BufferIsSKP(SkReadBuffer* buffer, SkPictInfo* pInfo) {
    // Check magic bytes.
    SkPictInfo info;
    SkASSERT(sizeof(kMagic) == sizeof(info.fMagic));

    if (!buffer->readByteArray(&info.fMagic, sizeof(kMagic))) {
        return false;
    }

    info.fVersion = buffer->readUInt();
    buffer->readRect(&info.fCullRect);
    info.fFlags = buffer->readUInt();

    if (!IsValidPictInfo(info)) {
        return false;
    }

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

SkPicture* SkPicture::Forwardport(const SkPictInfo& info, const SkPictureData* data) {
    if (!data) {
        return NULL;
    }
    SkPicturePlayback playback(data);
    SkPictureRecorder r;
    playback.draw(r.beginRecording(SkScalarCeilToInt(info.fCullRect.width()),
                                   SkScalarCeilToInt(info.fCullRect.height())),
                  NULL/*no callback*/);
    return r.endRecording();
}

SkPicture* SkPicture::CreateFromStream(SkStream* stream, InstallPixelRefProc proc) {
    SkPictInfo info;
    if (!InternalOnly_StreamIsSKP(stream, &info) || !stream->readBool()) {
        return NULL;
    }
    SkAutoTDelete<SkPictureData> data(SkPictureData::CreateFromStream(stream, info, proc));
    return Forwardport(info, data);
}

SkPicture* SkPicture::CreateFromBuffer(SkReadBuffer& buffer) {
    SkPictInfo info;
    if (!InternalOnly_BufferIsSKP(&buffer, &info) || !buffer.readBool()) {
        return NULL;
    }
    SkAutoTDelete<SkPictureData> data(SkPictureData::CreateFromBuffer(buffer, info));
    return Forwardport(info, data);
}

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->fCullRect = this->cullRect();
    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;
    }
}

// This for compatibility with serialization code only.  This is not cheap.
SkPictureData* SkPicture::Backport(const SkRecord& src, const SkPictInfo& info,
                                   SkPicture const* const drawablePicts[], int drawableCount) {
    SkPictureRecord rec(SkISize::Make(info.fCullRect.width(), info.fCullRect.height()), 0/*flags*/);
    rec.beginRecording();
        SkRecordDraw(src, &rec, drawablePicts, NULL, drawableCount, NULL/*bbh*/, NULL/*callback*/);
    rec.endRecording();
    return SkNEW_ARGS(SkPictureData, (rec, info, false/*deep copy ops?*/));
}

void SkPicture::serialize(SkWStream* stream, SkPixelSerializer* pixelSerializer) const {
    SkPictInfo info;
    this->createHeader(&info);
    SkAutoTDelete<SkPictureData> data(Backport(*fRecord, info, this->drawablePicts(),
                                               this->drawableCount()));

    stream->write(&info, sizeof(info));
    if (data) {
        stream->writeBool(true);
        data->serialize(stream, pixelSerializer);
    } else {
        stream->writeBool(false);
    }
}

void SkPicture::flatten(SkWriteBuffer& buffer) const {
    SkPictInfo info;
    this->createHeader(&info);
    SkAutoTDelete<SkPictureData> data(Backport(*fRecord, info, this->drawablePicts(),
                                               this->drawableCount()));

    buffer.writeByteArray(&info.fMagic, sizeof(info.fMagic));
    buffer.writeUInt(info.fVersion);
    buffer.writeRect(info.fCullRect);
    buffer.writeUInt(info.fFlags);
    if (data) {
        buffer.writeBool(true);
        data->flatten(buffer);
    } else {
        buffer.writeBool(false);
    }
}

#if SK_SUPPORT_GPU
bool SkPicture::suitableForGpuRasterization(GrContext*, const char **reason) const {
    return fAnalysis.suitableForGpuRasterization(reason, 0);
}
#endif

bool SkPicture::hasText()             const { return fAnalysis.fHasText; }
bool SkPicture::willPlayBackBitmaps() const { return fAnalysis.fWillPlaybackBitmaps; }
int  SkPicture::approximateOpCount()  const { return fRecord->count(); }

SkPicture::SkPicture(const SkRect& cullRect, SkRecord* record, SnapshotArray* drawablePicts,
                     SkBBoxHierarchy* bbh)
    : fUniqueID(next_picture_generation_id())
    , fCullRect(cullRect)
    , fRecord(SkRef(record))
    , fBBH(SkSafeRef(bbh))
    , fDrawablePicts(drawablePicts)     // take ownership
    , fAnalysis(*fRecord)
{}