src/core/SkPictureRecord.cpp

/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
#include "SkPictureRecord.h"
#include "SkTSearch.h"
#include "SkPixelRef.h"

#define MIN_WRITER_SIZE 16384
#define HEAP_BLOCK_SIZE 4096

SkPictureRecord::SkPictureRecord(uint32_t flags) :
        fHeap(HEAP_BLOCK_SIZE),
        fBitmaps(&fHeap),
        fMatrices(&fHeap),
        fPaints(&fHeap),
        fRegions(&fHeap),
        fWriter(MIN_WRITER_SIZE),
        fRecordFlags(flags) {
#ifdef SK_DEBUG_SIZE
    fPointBytes = fRectBytes = fTextBytes = 0;
    fPointWrites = fRectWrites = fTextWrites = 0;
#endif

    fRestoreOffsetStack.setReserve(32);
    fRestoreOffsetStack.push(0);

    fPathHeap = NULL;   // lazy allocate
    fFirstSavedLayerIndex = kNoSavedLayerIndex;
}

SkPictureRecord::~SkPictureRecord() {
    reset();
}

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

int SkPictureRecord::save(SaveFlags flags) {
    addDraw(SAVE);
    addInt(flags);

    fRestoreOffsetStack.push(0);

    validate();
    return this->INHERITED::save(flags);
}

int SkPictureRecord::saveLayer(const SkRect* bounds, const SkPaint* paint,
                               SaveFlags flags) {
    addDraw(SAVE_LAYER);
    addRectPtr(bounds);
    addPaintPtr(paint);
    addInt(flags);

    fRestoreOffsetStack.push(0);

    if (kNoSavedLayerIndex == fFirstSavedLayerIndex) {
        fFirstSavedLayerIndex = fRestoreOffsetStack.count();
    }

    validate();
    /*  Don't actually call saveLayer, because that will try to allocate an
        offscreen device (potentially very big) which we don't actually need
        at this time (and may not be able to afford since during record our
        clip starts out the size of the picture, which is often much larger
        than the size of the actual device we'll use during playback).
     */
    int count = this->INHERITED::save(flags);
    this->clipRectBounds(bounds, flags, NULL);
    return count;
}

bool SkPictureRecord::isDrawingToLayer() const {
    return fFirstSavedLayerIndex != kNoSavedLayerIndex;
}

void SkPictureRecord::restore() {
    // check for underflow
    if (fRestoreOffsetStack.count() == 0) {
        return;
    }

    fillRestoreOffsetPlaceholdersForCurrentStackLevel(
        (uint32_t)fWriter.size());

    if (fRestoreOffsetStack.count() == fFirstSavedLayerIndex) {
        fFirstSavedLayerIndex = kNoSavedLayerIndex;
    }

    fRestoreOffsetStack.pop();

    addDraw(RESTORE);
    validate();
    return this->INHERITED::restore();
}

bool SkPictureRecord::translate(SkScalar dx, SkScalar dy) {
    addDraw(TRANSLATE);
    addScalar(dx);
    addScalar(dy);
    validate();
    return this->INHERITED::translate(dx, dy);
}

bool SkPictureRecord::scale(SkScalar sx, SkScalar sy) {
    addDraw(SCALE);
    addScalar(sx);
    addScalar(sy);
    validate();
    return this->INHERITED::scale(sx, sy);
}

bool SkPictureRecord::rotate(SkScalar degrees) {
    addDraw(ROTATE);
    addScalar(degrees);
    validate();
    return this->INHERITED::rotate(degrees);
}

bool SkPictureRecord::skew(SkScalar sx, SkScalar sy) {
    addDraw(SKEW);
    addScalar(sx);
    addScalar(sy);
    validate();
    return this->INHERITED::skew(sx, sy);
}

bool SkPictureRecord::concat(const SkMatrix& matrix) {
    validate();
    addDraw(CONCAT);
    addMatrix(matrix);
    validate();
    return this->INHERITED::concat(matrix);
}

void SkPictureRecord::setMatrix(const SkMatrix& matrix) {
    validate();
    addDraw(SET_MATRIX);
    addMatrix(matrix);
    validate();
    this->INHERITED::setMatrix(matrix);
}

static bool regionOpExpands(SkRegion::Op op) {
    switch (op) {
        case SkRegion::kUnion_Op:
        case SkRegion::kXOR_Op:
        case SkRegion::kReverseDifference_Op:
        case SkRegion::kReplace_Op:
            return true;
        case SkRegion::kIntersect_Op:
        case SkRegion::kDifference_Op:
            return false;
        default:
            SkDEBUGFAIL("unknown region op");
            return false;
    }
}

void SkPictureRecord::fillRestoreOffsetPlaceholdersForCurrentStackLevel(
    uint32_t restoreOffset) {
    uint32_t offset = fRestoreOffsetStack.top();
    while (offset) {
        uint32_t* peek = fWriter.peek32(offset);
        offset = *peek;
        *peek = restoreOffset;
    }
}

void SkPictureRecord::endRecording() {
    // clear any remaining unhandled restore offset placeholders
    while (fRestoreOffsetStack.count()) {
        this->fillRestoreOffsetPlaceholdersForCurrentStackLevel(0);
        fRestoreOffsetStack.pop();
    }
}

void SkPictureRecord::recordRestoreOffsetPlaceholder(SkRegion::Op op) {
    if (regionOpExpands(op)) {
        // Run back through any previous clip ops, and mark their offset to
        // be 0, disabling their ability to trigger a jump-to-restore, otherwise
        // they could hide this clips ability to expand the clip (i.e. go from
        // empty to non-empty).
        fillRestoreOffsetPlaceholdersForCurrentStackLevel(0);
    }

    size_t offset = fWriter.size();
    // The RestoreOffset field is initially filled with a placeholder
    // value that points to the offset of the previous RestoreOffset
    // in the current stack level, thus forming a linked list so that
    // the restore offsets can be filled in when the corresponding 
    // restore command is recorded.
    addInt(fRestoreOffsetStack.top());
    fRestoreOffsetStack.top() = offset;
}

bool SkPictureRecord::clipRect(const SkRect& rect, SkRegion::Op op, bool doAA) {
    addDraw(CLIP_RECT);
    addRect(rect);
    addInt(ClipParams_pack(op, doAA));
    recordRestoreOffsetPlaceholder(op);

    validate();
    return this->INHERITED::clipRect(rect, op, doAA);
}

bool SkPictureRecord::clipPath(const SkPath& path, SkRegion::Op op, bool doAA) {
    addDraw(CLIP_PATH);
    addPath(path);
    addInt(ClipParams_pack(op, doAA));
    recordRestoreOffsetPlaceholder(op);

    validate();

    if (fRecordFlags & SkPicture::kUsePathBoundsForClip_RecordingFlag) {
        return this->INHERITED::clipRect(path.getBounds(), op, doAA);
    } else {
        return this->INHERITED::clipPath(path, op, doAA);
    }
}

bool SkPictureRecord::clipRegion(const SkRegion& region, SkRegion::Op op) {
    addDraw(CLIP_REGION);
    addRegion(region);
    addInt(ClipParams_pack(op, false));
    recordRestoreOffsetPlaceholder(op);

    validate();
    return this->INHERITED::clipRegion(region, op);
}

void SkPictureRecord::clear(SkColor color) {
    addDraw(DRAW_CLEAR);
    addInt(color);
    validate();
}

void SkPictureRecord::drawPaint(const SkPaint& paint) {
    addDraw(DRAW_PAINT);
    addPaint(paint);
    validate();
}

void SkPictureRecord::drawPoints(PointMode mode, size_t count, const SkPoint pts[],
                        const SkPaint& paint) {
    addDraw(DRAW_POINTS);
    addPaint(paint);
    addInt(mode);
    addInt(count);
    fWriter.writeMul4(pts, count * sizeof(SkPoint));
    validate();
}

void SkPictureRecord::drawRect(const SkRect& rect, const SkPaint& paint) {
    addDraw(DRAW_RECT);
    addPaint(paint);
    addRect(rect);
    validate();
}

void SkPictureRecord::drawPath(const SkPath& path, const SkPaint& paint) {
    addDraw(DRAW_PATH);
    addPaint(paint);
    addPath(path);
    validate();
}

void SkPictureRecord::drawBitmap(const SkBitmap& bitmap, SkScalar left, SkScalar top,
                        const SkPaint* paint = NULL) {
    addDraw(DRAW_BITMAP);
    addPaintPtr(paint);
    addBitmap(bitmap);
    addScalar(left);
    addScalar(top);
    validate();
}

void SkPictureRecord::drawBitmapRect(const SkBitmap& bitmap, const SkIRect* src,
                            const SkRect& dst, const SkPaint* paint) {
    addDraw(DRAW_BITMAP_RECT);
    addPaintPtr(paint);
    addBitmap(bitmap);
    addIRectPtr(src);  // may be null
    addRect(dst);
    validate();
}

void SkPictureRecord::drawBitmapMatrix(const SkBitmap& bitmap, const SkMatrix& matrix,
                                       const SkPaint* paint) {
    addDraw(DRAW_BITMAP_MATRIX);
    addPaintPtr(paint);
    addBitmap(bitmap);
    addMatrix(matrix);
    validate();
}

void SkPictureRecord::drawBitmapNine(const SkBitmap& bitmap, const SkIRect& center,
                                     const SkRect& dst, const SkPaint* paint) {
    addDraw(DRAW_BITMAP_NINE);
    addPaintPtr(paint);
    addBitmap(bitmap);
    addIRect(center);
    addRect(dst);
    validate();
}

void SkPictureRecord::drawSprite(const SkBitmap& bitmap, int left, int top,
                        const SkPaint* paint = NULL) {
    addDraw(DRAW_SPRITE);
    addPaintPtr(paint);
    addBitmap(bitmap);
    addInt(left);
    addInt(top);
    validate();
}

void SkPictureRecord::addFontMetricsTopBottom(const SkPaint& paint,
                                              SkScalar minY, SkScalar maxY) {
    SkPaint::FontMetrics metrics;
    paint.getFontMetrics(&metrics);
    SkRect bounds;
    // construct a rect so we can see any adjustments from the paint.
    // we use 0,1 for left,right, just so the rect isn't empty
    bounds.set(0, metrics.fTop + minY,
               SK_Scalar1, metrics.fBottom + maxY);
    (void)paint.computeFastBounds(bounds, &bounds);
    // now record the top and bottom
    addScalar(bounds.fTop);
    addScalar(bounds.fBottom);
}

void SkPictureRecord::drawText(const void* text, size_t byteLength, SkScalar x,
                      SkScalar y, const SkPaint& paint) {
    bool fast = !paint.isVerticalText() && paint.canComputeFastBounds();

    addDraw(fast ? DRAW_TEXT_TOP_BOTTOM : DRAW_TEXT);
    addPaint(paint);
    addText(text, byteLength);
    addScalar(x);
    addScalar(y);
    if (fast) {
        addFontMetricsTopBottom(paint, y, y);
    }
    validate();
}

void SkPictureRecord::drawPosText(const void* text, size_t byteLength,
                         const SkPoint pos[], const SkPaint& paint) {
    size_t points = paint.countText(text, byteLength);
    if (0 == points)
        return;

    bool canUseDrawH = true;
    SkScalar minY = pos[0].fY;
    SkScalar maxY = pos[0].fY;
    // check if the caller really should have used drawPosTextH()
    {
        const SkScalar firstY = pos[0].fY;
        for (size_t index = 1; index < points; index++) {
            if (pos[index].fY != firstY) {
                canUseDrawH = false;
                if (pos[index].fY < minY) {
                    minY = pos[index].fY;
                } else if (pos[index].fY > maxY) {
                    maxY = pos[index].fY;
                }
            }
        }
    }

    bool fastBounds = !paint.isVerticalText() && paint.canComputeFastBounds();
    bool fast = canUseDrawH && fastBounds;

    if (fast) {
        addDraw(DRAW_POS_TEXT_H_TOP_BOTTOM);
    } else if (canUseDrawH) {
        addDraw(DRAW_POS_TEXT_H);
    } else if (fastBounds) {
        addDraw(DRAW_POS_TEXT_TOP_BOTTOM);
    } else {
        addDraw(DRAW_POS_TEXT);
    }
    addPaint(paint);
    addText(text, byteLength);
    addInt(points);

#ifdef SK_DEBUG_SIZE
    size_t start = fWriter.size();
#endif
    if (canUseDrawH) {
        if (fast) {
            addFontMetricsTopBottom(paint, pos[0].fY, pos[0].fY);
        }
        addScalar(pos[0].fY);
        SkScalar* xptr = (SkScalar*)fWriter.reserve(points * sizeof(SkScalar));
        for (size_t index = 0; index < points; index++)
            *xptr++ = pos[index].fX;
    }
    else {
        fWriter.writeMul4(pos, points * sizeof(SkPoint));
        if (fastBounds) {
            addFontMetricsTopBottom(paint, minY, maxY);
        }
    }
#ifdef SK_DEBUG_SIZE
    fPointBytes += fWriter.size() - start;
    fPointWrites += points;
#endif
    validate();
}

void SkPictureRecord::drawPosTextH(const void* text, size_t byteLength,
                          const SkScalar xpos[], SkScalar constY,
                          const SkPaint& paint) {
    size_t points = paint.countText(text, byteLength);
    if (0 == points)
        return;

    bool fast = !paint.isVerticalText() && paint.canComputeFastBounds();

    addDraw(fast ? DRAW_POS_TEXT_H_TOP_BOTTOM : DRAW_POS_TEXT_H);
    addPaint(paint);
    addText(text, byteLength);
    addInt(points);

#ifdef SK_DEBUG_SIZE
    size_t start = fWriter.size();
#endif
    if (fast) {
        addFontMetricsTopBottom(paint, constY, constY);
    }
    addScalar(constY);
    fWriter.writeMul4(xpos, points * sizeof(SkScalar));
#ifdef SK_DEBUG_SIZE
    fPointBytes += fWriter.size() - start;
    fPointWrites += points;
#endif
    validate();
}

void SkPictureRecord::drawTextOnPath(const void* text, size_t byteLength,
                            const SkPath& path, const SkMatrix* matrix,
                            const SkPaint& paint) {
    addDraw(DRAW_TEXT_ON_PATH);
    addPaint(paint);
    addText(text, byteLength);
    addPath(path);
    addMatrixPtr(matrix);
    validate();
}

void SkPictureRecord::drawPicture(SkPicture& picture) {
    addDraw(DRAW_PICTURE);
    addPicture(picture);
    validate();
}

void SkPictureRecord::drawVertices(VertexMode vmode, int vertexCount,
                          const SkPoint vertices[], const SkPoint texs[],
                          const SkColor colors[], SkXfermode*,
                          const uint16_t indices[], int indexCount,
                          const SkPaint& paint) {
    uint32_t flags = 0;
    if (texs) {
        flags |= DRAW_VERTICES_HAS_TEXS;
    }
    if (colors) {
        flags |= DRAW_VERTICES_HAS_COLORS;
    }
    if (indexCount > 0) {
        flags |= DRAW_VERTICES_HAS_INDICES;
    }

    addDraw(DRAW_VERTICES);
    addPaint(paint);
    addInt(flags);
    addInt(vmode);
    addInt(vertexCount);
    addPoints(vertices, vertexCount);
    if (flags & DRAW_VERTICES_HAS_TEXS) {
        addPoints(texs, vertexCount);
    }
    if (flags & DRAW_VERTICES_HAS_COLORS) {
        fWriter.writeMul4(colors, vertexCount * sizeof(SkColor));
    }
    if (flags & DRAW_VERTICES_HAS_INDICES) {
        addInt(indexCount);
        fWriter.writePad(indices, indexCount * sizeof(uint16_t));
    }
}

void SkPictureRecord::drawData(const void* data, size_t length) {
    addDraw(DRAW_DATA);
    addInt(length);
    fWriter.writePad(data, length);
}

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

void SkPictureRecord::reset() {
    SkSafeUnref(fPathHeap);
    fPathHeap = NULL;

    fBitmaps.reset();
    fPixelRefDictionary.reset();
    fMatrices.reset();
    fPaints.reset();
    fPictureRefs.unrefAll();
    fRegions.reset();
    fWriter.reset();
    fHeap.reset();

    fRestoreOffsetStack.setCount(1);
    fRestoreOffsetStack.top() = 0;

    fRCSet.reset();
    fTFSet.reset();
}

void SkPictureRecord::addBitmap(const SkBitmap& bitmap) {
    addInt(find(bitmap));
}

void SkPictureRecord::addMatrix(const SkMatrix& matrix) {
    addMatrixPtr(&matrix);
}

void SkPictureRecord::addMatrixPtr(const SkMatrix* matrix) {
    this->addInt(matrix ? fMatrices.find(*matrix) : 0);
}

void SkPictureRecord::addPaint(const SkPaint& paint) {
    addPaintPtr(&paint);
}

void SkPictureRecord::addPaintPtr(const SkPaint* paint) {
    this->addInt(paint ? fPaints.find(*paint, &fRCSet, &fTFSet) : 0);
}

void SkPictureRecord::addPath(const SkPath& path) {
    if (NULL == fPathHeap) {
        fPathHeap = SkNEW(SkPathHeap);
    }
    addInt(fPathHeap->append(path));
}

void SkPictureRecord::addPicture(SkPicture& picture) {
    int index = fPictureRefs.find(&picture);
    if (index < 0) {    // not found
        index = fPictureRefs.count();
        *fPictureRefs.append() = &picture;
        picture.ref();
    }
    // follow the convention of recording a 1-based index
    addInt(index + 1);
}

void SkPictureRecord::addPoint(const SkPoint& point) {
#ifdef SK_DEBUG_SIZE
    size_t start = fWriter.size();
#endif
    fWriter.writePoint(point);
#ifdef SK_DEBUG_SIZE
    fPointBytes += fWriter.size() - start;
    fPointWrites++;
#endif
}

void SkPictureRecord::addPoints(const SkPoint pts[], int count) {
    fWriter.writeMul4(pts, count * sizeof(SkPoint));
#ifdef SK_DEBUG_SIZE
    fPointBytes += count * sizeof(SkPoint);
    fPointWrites++;
#endif
}

void SkPictureRecord::addRect(const SkRect& rect) {
#ifdef SK_DEBUG_SIZE
    size_t start = fWriter.size();
#endif
    fWriter.writeRect(rect);
#ifdef SK_DEBUG_SIZE
    fRectBytes += fWriter.size() - start;
    fRectWrites++;
#endif
}

void SkPictureRecord::addRectPtr(const SkRect* rect) {
    if (fWriter.writeBool(rect != NULL)) {
        fWriter.writeRect(*rect);
    }
}

void SkPictureRecord::addIRect(const SkIRect& rect) {
    fWriter.write(&rect, sizeof(rect));
}

void SkPictureRecord::addIRectPtr(const SkIRect* rect) {
    if (fWriter.writeBool(rect != NULL)) {
        *(SkIRect*)fWriter.reserve(sizeof(SkIRect)) = *rect;
    }
}

void SkPictureRecord::addRegion(const SkRegion& region) {
    addInt(fRegions.find(region));
}

void SkPictureRecord::addText(const void* text, size_t byteLength) {
#ifdef SK_DEBUG_SIZE
    size_t start = fWriter.size();
#endif
    addInt(byteLength);
    fWriter.writePad(text, byteLength);
#ifdef SK_DEBUG_SIZE
    fTextBytes += fWriter.size() - start;
    fTextWrites++;
#endif
}

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

bool SkPictureRecord::shouldFlattenPixels(const SkBitmap& bitmap) const {
    return (fRecordFlags &
        SkPicture::kFlattenMutableNonTexturePixelRefs_RecordingFlag)
        && !bitmap.isImmutable() && bitmap.pixelRef()
        && NULL == bitmap.getTexture();
}

int SkPictureRecord::find(const SkBitmap& bitmap) {
    int dictionaryIndex = 0;
    PixelRefDictionaryEntry entry;
    bool flattenPixels = shouldFlattenPixels(bitmap);
    if (flattenPixels) {
        // Flattened bitmap may be very large. First attempt a fast lookup
        // based on generation ID to avoid unnecessary flattening in
        // fBitmaps.find()
        entry.fKey = bitmap.pixelRef()->getGenerationID();
        dictionaryIndex = 
            SkTSearch<const PixelRefDictionaryEntry>(fPixelRefDictionary.begin(),
            fPixelRefDictionary.count(), entry, sizeof(entry));
        if (dictionaryIndex >= 0) {
            return fPixelRefDictionary[dictionaryIndex].fIndex;
        }
    }
    
    uint32_t writeFlags = flattenPixels ?
        SkFlattenableWriteBuffer::kForceFlattenBitmapPixels_Flag : 0;
    int index = fBitmaps.find(bitmap, &fRCSet, NULL, writeFlags);

    if (flattenPixels) {
        entry.fIndex = index;
        dictionaryIndex = ~dictionaryIndex;
        *fPixelRefDictionary.insert(dictionaryIndex) = entry;
    }
    return index;
}

#ifdef SK_DEBUG_SIZE
size_t SkPictureRecord::size() const {
    size_t result = 0;
    size_t sizeData;
    bitmaps(&sizeData);
    result += sizeData;
    matrices(&sizeData);
    result += sizeData;
    paints(&sizeData);
    result += sizeData;
    paths(&sizeData);
    result += sizeData;
    pictures(&sizeData);
    result += sizeData;
    regions(&sizeData);
    result += sizeData;
    result += streamlen();
    return result;
}

int SkPictureRecord::bitmaps(size_t* size) const {
    size_t result = 0;
    int count = fBitmaps.count();
    for (int index = 0; index < count; index++)
        result += sizeof(fBitmaps[index]) + fBitmaps[index]->size();
    *size = result;
    return count;
}

int SkPictureRecord::matrices(size_t* size) const {
    int count = fMatrices.count();
    *size = sizeof(fMatrices[0]) * count;
    return count;
}

int SkPictureRecord::paints(size_t* size) const {
    size_t result = 0;
    int count = fPaints.count();
    for (int index = 0; index < count; index++)
        result += sizeof(fPaints[index]) + fPaints[index]->size();
    *size = result;
    return count;
}

int SkPictureRecord::paths(size_t* size) const {
    size_t result = 0;
    int count = fPaths.count();
    for (int index = 0; index < count; index++)
        result += sizeof(fPaths[index]) + fPaths[index]->size();
    *size = result;
    return count;
}

int SkPictureRecord::regions(size_t* size) const {
    size_t result = 0;
    int count = fRegions.count();
    for (int index = 0; index < count; index++)
        result += sizeof(fRegions[index]) + fRegions[index]->size();
    *size = result;
    return count;
}

size_t SkPictureRecord::streamlen() const {
    return fWriter.size();
}
#endif

#ifdef SK_DEBUG_VALIDATE
void SkPictureRecord::validate() const {
    validateBitmaps();
    validateMatrices();
    validatePaints();
    validatePaths();
    validatePictures();
    validateRegions();
}

void SkPictureRecord::validateBitmaps() const {
    int count = fBitmaps.count();
    SkASSERT((unsigned) count < 0x1000);
    for (int index = 0; index < count; index++) {
        const SkFlatBitmap* bitPtr = fBitmaps[index];
        SkASSERT(bitPtr);
        bitPtr->validate();
    }
}

void SkPictureRecord::validateMatrices() const {
    int count = fMatrices.count();
    SkASSERT((unsigned) count < 0x1000);
    for (int index = 0; index < count; index++) {
        const SkFlatMatrix* matrix = fMatrices[index];
        SkASSERT(matrix);
        matrix->validate();
    }
}

void SkPictureRecord::validatePaints() const {
    int count = fPaints.count();
    SkASSERT((unsigned) count < 0x1000);
    for (int index = 0; index < count; index++) {
        const SkFlatPaint* paint = fPaints[index];
        SkASSERT(paint);
//            paint->validate();
    }
}

void SkPictureRecord::validatePaths() const {
    int count = fPaths.count();
    SkASSERT((unsigned) count < 0x1000);
    for (int index = 0; index < count; index++) {
        const SkFlatPath* path = fPaths[index];
        SkASSERT(path);
        path->validate();
    }
}

void SkPictureRecord::validateRegions() const {
    int count = fRegions.count();
    SkASSERT((unsigned) count < 0x1000);
    for (int index = 0; index < count; index++) {
        const SkFlatRegion* region = fRegions[index];
        SkASSERT(region);
        region->validate();
    }
}
#endif