C++ png_get_progressive_ptr函数代码示例

void
nsPNGDecoder::end_callback(png_structp png_ptr, png_infop info_ptr)
{
  /* libpng comments:
   *
   * this function is called when the whole image has been read,
   * including any chunks after the image (up to and including
   * the IEND).  You will usually have the same info chunk as you
   * had in the header, although some data may have been added
   * to the comments and time fields.
   *
   * Most people won't do much here, perhaps setting a flag that
   * marks the image as finished.
   */

  nsPNGDecoder* decoder =
               static_cast<nsPNGDecoder*>(png_get_progressive_ptr(png_ptr));

  // We shouldn't get here if we've hit an error
  MOZ_ASSERT(!decoder->HasError(), "Finishing up PNG but hit error!");

  int32_t loop_count = 0;
#ifdef PNG_APNG_SUPPORTED
  if (png_get_valid(png_ptr, info_ptr, PNG_INFO_acTL)) {
    int32_t num_plays = png_get_num_plays(png_ptr, info_ptr);
    loop_count = num_plays - 1;
  }
#endif

  // Send final notifications
  decoder->EndImageFrame();
  decoder->PostDecodeDone(loop_count);
}

static void read_data_fn(png_structp png_ptr, png_bytep data, png_size_t length)
{
	struct png_t* png = (struct png_t*)png_get_progressive_ptr(png_ptr);
	if(png->pos + length > png->size) png_error(png_ptr, "Read Error");
	memcpy(data, &png->data[png->pos], length);
	png->pos += length;
}

void PngReader::end_callback(
    png_structp png, png_infop info )
{
    PngReader* reader =
        ( PngReader* )png_get_progressive_ptr( png );
    reader->m_finished = true;
}

/* Called after reading the entire image */
static void
png_end_callback   (png_structp png_read_ptr,
                    png_infop   png_info_ptr)
{
        LoadContext* lc;

        lc = png_get_progressive_ptr(png_read_ptr);

        if (lc->fatal_error_occurred)
                return;
}

void pngDecEndCallback(png_structp png_ptr, png_infop info)
{
	PngStream* stream = (PngStream*)png_get_progressive_ptr(png_ptr);
	if (!stream)
	{
		cellPngDec.error("Failed to obtain streamPtr in endCallback.");
		return;
	}

	stream->endOfFile = true;
}

void pngDecInfoCallback(png_structp png_ptr, png_infop info)
{
	PngStream* stream = (PngStream*)png_get_progressive_ptr(png_ptr);
	if (!stream)
	{
		cellPngDec.error("Failed to obtain streamPtr in rowCallback.");
		return;
	}

	const size_t remaining = png_process_data_pause(png_ptr, false);
	stream->buffer->cursor += (stream->buffer->length - remaining);
}

static void row_callback(png_structp png_s, png_bytep new_row,
			 png_uint_32 row_num, int pass)
{
	nspng_content *png_c = png_get_progressive_ptr(png_s);
	unsigned long rowbytes = png_c->rowbytes;
	unsigned char *buffer, *row;

	/* Give up if there's no bitmap */
	if (png_c->bitmap == NULL)
		return;

	/* Abort if we've not got any data */
	if (new_row == NULL)
		return;

	/* Get bitmap buffer */
	buffer = bitmap_get_buffer(png_c->bitmap);
	if (buffer == NULL) {
		/* No buffer, bail out */
		longjmp(png_jmpbuf(png_s), 1);
	}

	/* Calculate address of row start */
	row = buffer + (png_c->rowstride * row_num);

	/* Handle interlaced sprites using the Adam7 algorithm */
	if (png_c->interlace) {
		unsigned long dst_off;
		unsigned long src_off = 0;
		unsigned int start, step;

		start = interlace_start[pass];
		step = interlace_step[pass];
		row_num = interlace_row_start[pass] +
			interlace_row_step[pass] * row_num;

		/* Copy the data to our current row taking interlacing
		 * into consideration */
		row = buffer + (png_c->rowstride * row_num);

		for (dst_off = start; dst_off < rowbytes; dst_off += step) {
			row[dst_off++] = new_row[src_off++];
			row[dst_off++] = new_row[src_off++];
			row[dst_off++] = new_row[src_off++];
			row[dst_off++] = new_row[src_off++];
		}
	} else {
		/* Do a fast memcpy of the row data */
		memcpy(row, new_row, rowbytes);
	}
}

void PngReader::row_callback(
    png_structp png, png_bytep row,
    png_uint_32 rowpos, int pass )
{
    if( !row )
    {
        return;
    }
    PngReader* reader =
        ( PngReader* )png_get_progressive_ptr( png );
    png_progressive_combine_row(
        png,
        reader->m_data->m_data +
        reader->m_stride * ( reader->m_height - rowpos - 1 ),
        row );
}

static void _png_get_row_func(png_structp png_ptr,
                              png_bytep new_row,
                              png_uint_32 row_num,
                              int pass) {
  FXPNG_Context* p = (FXPNG_Context*)png_get_progressive_ptr(png_ptr);
  if (!p)
    return;

  CCodec_PngModule* pModule = (CCodec_PngModule*)p->parent_ptr;
  uint8_t* src_buf = nullptr;
  if (!pModule->AskScanlineBufCallback(p->child_ptr, row_num, src_buf)) {
    png_error(png_ptr, "Ask Scanline buffer Callback Error");
  }
  if (src_buf) {
    png_progressive_combine_row(png_ptr, src_buf, new_row);
  }
  pModule->FillScanlineBufCompletedCallback(p->child_ptr, pass, row_num);
}

    bool decode(const SharedBuffer& data, bool sizeOnly)
    {
        m_decodingSizeOnly = sizeOnly;
        PNGImageDecoder* decoder = static_cast<PNGImageDecoder*>(png_get_progressive_ptr(m_png));

        // We need to do the setjmp here. Otherwise bad things will happen.
        if (setjmp(JMPBUF(m_png)))
            return decoder->setFailed();

        const char* segment;
        while (unsigned segmentLength = data.getSomeData(segment, m_readOffset)) {
            m_readOffset += segmentLength;
            m_currentBufferSize = m_readOffset;
            png_process_data(m_png, m_info, reinterpret_cast<png_bytep>(const_cast<char*>(segment)), segmentLength);
            // We explicitly specify the superclass isSizeAvailable() because we
            // merely want to check if we've managed to set the size, not
            // (recursively) trigger additional decoding if we haven't.
            if (sizeOnly ? decoder->ImageDecoder::isSizeAvailable() : decoder->isComplete())
                return true;
        }
        return false;
    }

/* Called for each row; note that you will get duplicate row numbers
   for interlaced PNGs */
static void
png_row_callback   (png_structp png_read_ptr,
                    png_bytep   new_row,
                    png_uint_32 row_num,
                    int pass_num)
{
        LoadContext* lc;
        guchar* old_row = NULL;

        lc = png_get_progressive_ptr(png_read_ptr);

        if (lc->fatal_error_occurred)
                return;

        if (row_num >= lc->pixbuf->height) {
                lc->fatal_error_occurred = TRUE;
                if (lc->error && *lc->error == NULL) {
                        g_set_error_literal (lc->error,
                                             GDK_PIXBUF_ERROR,
                                             GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
                                             _("Fatal error reading PNG image file"));
                }
                return;
        }

        if (lc->first_row_seen_in_chunk < 0) {
                lc->first_row_seen_in_chunk = row_num;
                lc->first_pass_seen_in_chunk = pass_num;
        }

        lc->max_row_seen_in_chunk = MAX(lc->max_row_seen_in_chunk, ((gint)row_num));
        lc->last_row_seen_in_chunk = row_num;
        lc->last_pass_seen_in_chunk = pass_num;
        
        old_row = lc->pixbuf->pixels + (row_num * lc->pixbuf->rowstride);

        png_progressive_combine_row(lc->png_read_ptr, old_row, new_row);
}

void PngReader::info_callback(
    png_structp png, png_infop info )
{
    PngReader* reader =
        ( PngReader* )png_get_progressive_ptr( png );
    int bitdepth;
    int colortype;
    png_get_IHDR( png, info,
                  ( png_uint_32* )&reader->m_width,
                  ( png_uint_32* )&reader->m_height,
                  &bitdepth, &colortype, 0, 0, 0 );
    formattable[ reader->m_format ].setformat(
        png, info, bitdepth, colortype );
    png_set_interlace_handling( png );
    png_read_update_info( png, info );
    reader->m_stride =
        reader->m_width *
        formattable[ reader->m_format ].pixelstride;
    size_t size = reader->m_stride * reader->m_height;
    reader->m_data = DataBuffer::create(
                         size, size, 0 );
    memset( reader->m_data->m_data, 0, size );
}

void pngDecRowCallback(png_structp png_ptr, png_bytep new_row, png_uint_32 row_num, int pass)
{
	PngStream* stream = (PngStream*)png_get_progressive_ptr(png_ptr);
	if (!stream)
	{
		cellPngDec.error("Failed to obtain streamPtr in rowCallback.");
		return;
	}

	// we have to check this everytime as this func can be called multiple times per row, and/or only once per row
	if (stream->nextRow + stream->outputCounts == row_num)
		stream->nextRow = row_num;

	if (stream->ppuContext && (stream->nextRow == row_num  || pass > 0))
	{
		if (pass > 0 )
		{
			stream->cbDispInfo->scanPassCount = pass;
			stream->cbDispInfo->nextOutputStartY = row_num;
		}
		else {
			stream->cbDispInfo->scanPassCount = 0;
			stream->cbDispInfo->nextOutputStartY = 0;
		}

		stream->cbDispInfo->outputImage = stream->cbDispParam->nextOutputImage;
		stream->cbCtrlDisp.cbCtrlDispFunc(*stream->ppuContext, stream->cbDispInfo, stream->cbDispParam, stream->cbCtrlDisp.cbCtrlDispArg);
		stream->cbDispInfo->outputStartY = row_num;
	}
	u8* data;
	if (pass > 0)
		data = static_cast<u8*>(stream->cbDispParam->nextOutputImage.get_ptr());
	else
		data = static_cast<u8*>(stream->cbDispParam->nextOutputImage.get_ptr()) + ((row_num - stream->cbDispInfo->outputStartY) * stream->cbDispInfo->outputFrameWidthByte);

	png_progressive_combine_row(png_ptr, data, new_row);
}

/**
 * info_callback -- PNG header has been completely received, prepare to process
 * image data
 */
static void info_callback(png_structp png_s, png_infop info)
{
	int interlace;
	png_uint_32 width, height;
	nspng_content *png_c = png_get_progressive_ptr(png_s);

	width = png_get_image_width(png_s, info);
	height = png_get_image_height(png_s, info);
	interlace = png_get_interlace_type(png_s, info);

	png_c->base.width = width;
	png_c->base.height = height;
	png_c->base.size += width * height * 4;

	/* see if progressive-conversion should continue */
	if (image_cache_speculate((struct content *)png_c) == false) {
		longjmp(png_jmpbuf(png_s), CBERR_NOPRE);
	}

	/* Claim the required memory for the converted PNG */
	png_c->bitmap = bitmap_create(width, height, BITMAP_NEW);
	if (png_c->bitmap == NULL) {
		/* Failed to create bitmap skip pre-conversion */
		longjmp(png_jmpbuf(png_s), CBERR_NOPRE);
	}

	png_c->rowstride = bitmap_get_rowstride(png_c->bitmap);
	png_c->bpp = bitmap_get_bpp(png_c->bitmap);

	nspng_setup_transforms(png_s, info);

	png_c->rowbytes = png_get_rowbytes(png_s, info);
	png_c->interlace = (interlace == PNG_INTERLACE_ADAM7);

	LOG(("size %li * %li, rowbytes %zu", (unsigned long)width,
	     (unsigned long)height, png_c->rowbytes));
}

static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr)
{
    mainprog_info  *mainprog_ptr;
    int  color_type, bit_depth;
    png_uint_32 width, height;
#ifdef PNG_FLOATING_POINT_SUPPORTED
    double  gamma;
#else
    png_fixed_point gamma;
#endif


    /* setjmp() doesn't make sense here, because we'd either have to exit(),
     * longjmp() ourselves, or return control to libpng, which doesn't want
     * to see us again.  By not doing anything here, libpng will instead jump
     * to readpng2_decode_data(), which can return an error value to the main
     * program. */


    /* retrieve the pointer to our special-purpose struct, using the png_ptr
     * that libpng passed back to us (i.e., not a global this time--there's
     * no real difference for a single image, but for a multithreaded browser
     * decoding several PNG images at the same time, one needs to avoid mixing
     * up different images' structs) */

    mainprog_ptr = png_get_progressive_ptr(png_ptr);

    if (mainprog_ptr == NULL) {         /* we be hosed */
        fprintf(stderr,
          "readpng2 error:  main struct not recoverable in info_callback.\n");
        fflush(stderr);
        return;
        /*
         * Alternatively, we could call our error-handler just like libpng
         * does, which would effectively terminate the program.  Since this
         * can only happen if png_ptr gets redirected somewhere odd or the
         * main PNG struct gets wiped, we're probably toast anyway.  (If
         * png_ptr itself is NULL, we would not have been called.)
         */
    }


    /* this is just like in the non-progressive case */

    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type,
       NULL, NULL, NULL);
    mainprog_ptr->width = (ulg)width;
    mainprog_ptr->height = (ulg)height;


    /* since we know we've read all of the PNG file's "header" (i.e., up
     * to IDAT), we can check for a background color here */

    if (mainprog_ptr->need_bgcolor &&
        png_get_valid(png_ptr, info_ptr, PNG_INFO_bKGD))
    {
        png_color_16p pBackground;

        /* it is not obvious from the libpng documentation, but this function
         * takes a pointer to a pointer, and it always returns valid red,
         * green and blue values, regardless of color_type: */
        png_get_bKGD(png_ptr, info_ptr, &pBackground);

        /* however, it always returns the raw bKGD data, regardless of any
         * bit-depth transformations, so check depth and adjust if necessary */
        if (bit_depth == 16) {
            mainprog_ptr->bg_red   = pBackground->red   >> 8;
            mainprog_ptr->bg_green = pBackground->green >> 8;
            mainprog_ptr->bg_blue  = pBackground->blue  >> 8;
        } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) {