gecko-dev/gfx/thebes/gfxImageSurface.h

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef GFX_IMAGESURFACE_H
#define GFX_IMAGESURFACE_H

#include "mozilla/MemoryReporting.h"
#include "mozilla/RefPtr.h"
#include "gfxASurface.h"
#include "nsSize.h"

// ARGB -- raw buffer.. wont be changed.. good for storing data.

class gfxSubimageSurface;

namespace mozilla {
namespace gfx {
class DataSourceSurface;
class SourceSurface;
}  // namespace gfx
}  // namespace mozilla

/**
 * A raw image buffer. The format can be set in the constructor. Its main
 * purpose is for storing read-only images and using it as a source surface,
 * but it can also be drawn to.
 */
class gfxImageSurface : public gfxASurface {
 public:
  /**
   * Construct an image surface around an existing buffer of image data.
   * @param aData A buffer containing the image data
   * @param aSize The size of the buffer
   * @param aStride The stride of the buffer
   * @param format Format of the data
   *
   * @see gfxImageFormat
   */
  gfxImageSurface(unsigned char* aData, const mozilla::gfx::IntSize& aSize,
                  long aStride, gfxImageFormat aFormat);

  /**
   * Construct an image surface.
   * @param aSize The size of the buffer
   * @param format Format of the data
   *
   * @see gfxImageFormat
   */
  gfxImageSurface(const mozilla::gfx::IntSize& size, gfxImageFormat format,
                  bool aClear = true);

  /**
   * Construct an image surface, with a specified stride and allowing the
   * allocation of more memory than required for the storage of the surface
   * itself.  When aStride and aMinimalAllocation are <=0, this constructor
   * is the equivalent of the preceeding one.
   *
   * @param format Format of the data
   * @param aSize The size of the buffer
   * @param aStride The stride of the buffer - if <=0, use ComputeStride()
   * @param aMinimalAllocation Allocate at least this many bytes.  If smaller
   *        than width * stride, or width*stride <=0, this value is ignored.
   * @param aClear
   *
   * @see gfxImageFormat
   */
  gfxImageSurface(const mozilla::gfx::IntSize& aSize, gfxImageFormat aFormat,
                  long aStride, int32_t aMinimalAllocation, bool aClear);

  explicit gfxImageSurface(cairo_surface_t* csurf);

  virtual ~gfxImageSurface();

  // ImageSurface methods
  gfxImageFormat Format() const { return mFormat; }

  virtual const mozilla::gfx::IntSize GetSize() const override { return mSize; }
  int32_t Width() const {
    if (mSize.width < 0) {
      return 0;
    }
    return mSize.width;
  }
  int32_t Height() const {
    if (mSize.height < 0) {
      return 0;
    }
    return mSize.height;
  }

  /**
   * Distance in bytes between the start of a line and the start of the
   * next line.
   */
  int32_t Stride() const { return mStride; }
  /**
   * Returns a pointer for the image data. Users of this function can
   * write to it, but must not attempt to free the buffer.
   */
  unsigned char* Data() const {
    return mData;
  }  // delete this data under us and die.
  /**
   * Returns the total size of the image data.
   */
  int32_t GetDataSize() const {
    if (mStride < 0 || mSize.height < 0) {
      return 0;
    }
    return mStride * mSize.height;
  }

  /* Fast copy from another image surface; returns TRUE if successful, FALSE
   * otherwise */
  bool CopyFrom(gfxImageSurface* other);

  /**
   * Fast copy from a source surface; returns TRUE if successful, FALSE
   * otherwise Assumes that the format of this surface is compatable with
   * aSurface
   */
  bool CopyFrom(mozilla::gfx::SourceSurface* aSurface);

  /**
   * Fast copy to a source surface; returns TRUE if successful, FALSE otherwise
   * Assumes that the format of this surface is compatible with aSurface
   */
  bool CopyTo(mozilla::gfx::SourceSurface* aSurface);

  /**
   * Copy to a Moz2D DataSourceSurface.
   * Marked as virtual so that browsercomps can access this method.
   */
  virtual already_AddRefed<mozilla::gfx::DataSourceSurface>
  CopyToB8G8R8A8DataSourceSurface();

  /* return new Subimage with pointing to original image starting from aRect.pos
   * and size of aRect.size. New subimage keeping current image reference
   */
  already_AddRefed<gfxSubimageSurface> GetSubimage(const gfxRect& aRect);

  virtual already_AddRefed<gfxImageSurface> GetAsImageSurface() override;

  /** See gfxASurface.h. */
  static long ComputeStride(const mozilla::gfx::IntSize&, gfxImageFormat);

  virtual size_t SizeOfExcludingThis(
      mozilla::MallocSizeOf aMallocSizeOf) const override;
  virtual size_t SizeOfIncludingThis(
      mozilla::MallocSizeOf aMallocSizeOf) const override;
  virtual bool SizeOfIsMeasured() const override;

 protected:
  gfxImageSurface();
  void InitWithData(unsigned char* aData, const mozilla::gfx::IntSize& aSize,
                    long aStride, gfxImageFormat aFormat);
  /**
   * See the parameters to the matching constructor.  This should only
   * be called once, in the constructor, which has already set mSize
   * and mFormat.
   */
  void AllocateAndInit(long aStride, int32_t aMinimalAllocation, bool aClear);
  void InitFromSurface(cairo_surface_t* csurf);

  long ComputeStride() const {
    if (mSize.height < 0 || mSize.width < 0) {
      return 0;
    }
    return ComputeStride(mSize, mFormat);
  }

  void MakeInvalid();

  mozilla::gfx::IntSize mSize;
  bool mOwnsData;
  unsigned char* mData;
  gfxImageFormat mFormat;
  long mStride;
};

class gfxSubimageSurface : public gfxImageSurface {
 protected:
  friend class gfxImageSurface;
  gfxSubimageSurface(gfxImageSurface* aParent, unsigned char* aData,
                     const mozilla::gfx::IntSize& aSize,
                     gfxImageFormat aFormat);

 private:
  RefPtr<gfxImageSurface> mParent;
};

#endif /* GFX_IMAGESURFACE_H */