src/pdf/SkPDFDevice.h

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

#ifndef SkPDFDevice_DEFINED
#define SkPDFDevice_DEFINED

#include "include/core/SkBitmap.h"
#include "include/core/SkCanvas.h"
#include "include/core/SkData.h"
#include "include/core/SkPaint.h"
#include "include/core/SkRect.h"
#include "include/core/SkRefCnt.h"
#include "include/core/SkStream.h"
#include "include/private/SkTHash.h"
#include "src/core/SkClipStack.h"
#include "src/core/SkClipStackDevice.h"
#include "src/core/SkTextBlobPriv.h"
#include "src/pdf/SkKeyedImage.h"
#include "src/pdf/SkPDFGraphicStackState.h"
#include "src/pdf/SkPDFTypes.h"

#include <vector>

class SkGlyphRunList;
class SkKeyedImage;
class SkPDFArray;
class SkPDFDevice;
class SkPDFDict;
class SkPDFDocument;
class SkPDFFont;
class SkPDFObject;
class SkPath;
class SkRRect;
struct SkPDFIndirectReference;

/**
 *  \class SkPDFDevice
 *
 *  An SkPDFDevice is the drawing context for a page or layer of PDF
 *  content.
 */
class SkPDFDevice final : public SkClipStackDevice {
public:
    /**
     *  @param pageSize Page size in point units.
     *         1 point == 127/360 mm == 1/72 inch
     *  @param document  A non-null pointer back to the
     *         PDFDocument object.  The document is responsible for
     *         de-duplicating across pages (via the SkPDFDocument) and
     *         for early serializing of large immutable objects, such
     *         as images (via SkPDFDocument::serialize()).
     *  @param initialTransform Transform to be applied to the entire page.
     */
    SkPDFDevice(SkISize pageSize, SkPDFDocument* document,
                const SkMatrix& initialTransform = SkMatrix::I());

    sk_sp<SkPDFDevice> makeCongruentDevice() {
        return sk_make_sp<SkPDFDevice>(this->size(), fDocument);
    }

    ~SkPDFDevice() override;

    /**
     *  These are called inside the per-device-layer loop for each draw call.
     *  When these are called, we have already applied any saveLayer
     *  operations, and are handling any looping from the paint.
     */
    void drawPaint(const SkPaint& paint) override;
    void drawPoints(SkCanvas::PointMode mode,
                    size_t count, const SkPoint[],
                    const SkPaint& paint) override;
    void drawRect(const SkRect& r, const SkPaint& paint) override;
    void drawOval(const SkRect& oval, const SkPaint& paint) override;
    void drawRRect(const SkRRect& rr, const SkPaint& paint) override;
    void drawPath(const SkPath& origpath, const SkPaint& paint, bool pathIsMutable) override;

    void drawImageRect(const SkImage*,
                       const SkRect* src,
                       const SkRect& dst,
                       const SkSamplingOptions&,
                       const SkPaint&,
                       SkCanvas::SrcRectConstraint) override;
    void onDrawGlyphRunList(const SkGlyphRunList& glyphRunList, const SkPaint& paint) override;
    void drawVertices(const SkVertices*, sk_sp<SkBlender>, const SkPaint&) override;
    void drawCustomMesh(SkCustomMesh, sk_sp<SkBlender>, const SkPaint&) override;

    // PDF specific methods.
    void drawSprite(const SkBitmap& bitmap, int x, int y,
                    const SkPaint& paint);

    /** Create the resource dictionary for this device. Destructive. */
    std::unique_ptr<SkPDFDict> makeResourceDict();

    /** Returns a SkStream with the page contents.
     */
    std::unique_ptr<SkStreamAsset> content();

    SkISize size() const { return this->imageInfo().dimensions(); }
    SkIRect bounds() const { return this->imageInfo().bounds(); }

    const SkMatrix& initialTransform() const { return fInitialTransform; }

protected:
    sk_sp<SkSurface> makeSurface(const SkImageInfo&, const SkSurfaceProps&) override;

    void drawAnnotation(const SkRect&, const char key[], SkData* value) override;

    void drawDevice(SkBaseDevice*, const SkSamplingOptions&, const SkPaint&) override;
    void drawSpecial(SkSpecialImage*, const SkMatrix&, const SkSamplingOptions&,
                     const SkPaint&) override;

    sk_sp<SkSpecialImage> makeSpecial(const SkBitmap&) override;
    sk_sp<SkSpecialImage> makeSpecial(const SkImage*) override;
    SkImageFilterCache* getImageFilterCache() override;

private:
    // TODO(vandebo): push most of SkPDFDevice's state into a core object in
    // order to get the right access levels without using friend.
    friend class ScopedContentEntry;

    SkMatrix fInitialTransform;

    SkTHashSet<SkPDFIndirectReference> fGraphicStateResources;
    SkTHashSet<SkPDFIndirectReference> fXObjectResources;
    SkTHashSet<SkPDFIndirectReference> fShaderResources;
    SkTHashSet<SkPDFIndirectReference> fFontResources;
    int fNodeId;

    SkDynamicMemoryWStream fContent;
    SkDynamicMemoryWStream fContentBuffer;
    bool fNeedsExtraSave = false;
    SkPDFGraphicStackState fActiveStackState;
    SkPDFDocument* fDocument;

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

    SkBaseDevice* onCreateDevice(const CreateInfo&, const SkPaint*) override;

    // Set alpha to true if making a transparency group form x-objects.
    SkPDFIndirectReference makeFormXObjectFromDevice(bool alpha = false);
    SkPDFIndirectReference makeFormXObjectFromDevice(SkIRect bbox, bool alpha = false);

    void drawFormXObjectWithMask(SkPDFIndirectReference xObject,
                                 SkPDFIndirectReference sMask,
                                 SkBlendMode,
                                 bool invertClip);

    // If the paint or clip is such that we shouldn't draw anything, this
    // returns nullptr and does not create a content entry.
    // setUpContentEntry and finishContentEntry can be used directly, but
    // the preferred method is to use the ScopedContentEntry helper class.
    SkDynamicMemoryWStream* setUpContentEntry(const SkClipStack* clipStack,
                                              const SkMatrix& matrix,
                                              const SkPaint& paint,
                                              SkScalar,
                                              SkPDFIndirectReference* dst);
    void finishContentEntry(const SkClipStack*, SkBlendMode, SkPDFIndirectReference, SkPath*);
    bool isContentEmpty();

    void internalDrawGlyphRun(const SkGlyphRun& glyphRun, SkPoint offset, const SkPaint& runPaint);
    void drawGlyphRunAsPath(const SkGlyphRun& glyphRun, SkPoint offset, const SkPaint& runPaint);

    void internalDrawImageRect(SkKeyedImage,
                               const SkRect* src,
                               const SkRect& dst,
                               const SkSamplingOptions&,
                               const SkPaint&,
                               const SkMatrix& canvasTransformationMatrix);

    void internalDrawPath(const SkClipStack&,
                          const SkMatrix&,
                          const SkPath&,
                          const SkPaint&,
                          bool pathIsMutable);

    void internalDrawPathWithFilter(const SkClipStack& clipStack,
                                    const SkMatrix& ctm,
                                    const SkPath& origPath,
                                    const SkPaint& paint);

    bool handleInversePath(const SkPath& origPath, const SkPaint& paint, bool pathIsMutable);

    void clearMaskOnGraphicState(SkDynamicMemoryWStream*);
    void setGraphicState(SkPDFIndirectReference gs, SkDynamicMemoryWStream*);
    void drawFormXObject(SkPDFIndirectReference xObject, SkDynamicMemoryWStream*);

    bool hasEmptyClip() const { return this->cs().isEmpty(this->bounds()); }

    void reset();

    using INHERITED = SkClipStackDevice;
};

#endif