cairo-pdf-surface.c

按照官方的说法：Cairo is a vector graphics library with cross-device output support. 翻译过来

				cairo_rectangle_int16_t *rectangle)
{
    cairo_pdf_surface_t *surface = abstract_surface;

    rectangle->x = 0;
    rectangle->y = 0;

    /* XXX: The conversion to integers here is pretty bogus, (not to
     * mention the aribitray limitation of width to a short(!). We
     * may need to come up with a better interface for get_size.
     */
    rectangle->width  = (int) ceil (surface->width);
    rectangle->height = (int) ceil (surface->height);

    return CAIRO_STATUS_SUCCESS;
}

typedef struct _pdf_path_info {
    cairo_output_stream_t   *output;
    cairo_matrix_t	    *ctm_inverse;
} pdf_path_info_t;

static cairo_status_t
_cairo_pdf_path_move_to (void *closure, cairo_point_t *point)
{
    pdf_path_info_t *info = closure;
    double x = _cairo_fixed_to_double (point->x);
    double y = _cairo_fixed_to_double (point->y);

    if (info->ctm_inverse)
	cairo_matrix_transform_point (info->ctm_inverse, &x, &y);

    _cairo_output_stream_printf (info->output,
				 "%f %f m ", x, y);

    return CAIRO_STATUS_SUCCESS;
}

static cairo_status_t
_cairo_pdf_path_line_to (void *closure, cairo_point_t *point)
{
    pdf_path_info_t *info = closure;
    double x = _cairo_fixed_to_double (point->x);
    double y = _cairo_fixed_to_double (point->y);

    if (info->ctm_inverse)
	cairo_matrix_transform_point (info->ctm_inverse, &x, &y);

    _cairo_output_stream_printf (info->output,
				 "%f %f l ", x, y);
    return CAIRO_STATUS_SUCCESS;
}

static cairo_status_t
_cairo_pdf_path_curve_to (void          *closure,
			  cairo_point_t *b,
			  cairo_point_t *c,
			  cairo_point_t *d)
{
    pdf_path_info_t *info = closure;
    double bx = _cairo_fixed_to_double (b->x);
    double by = _cairo_fixed_to_double (b->y);
    double cx = _cairo_fixed_to_double (c->x);
    double cy = _cairo_fixed_to_double (c->y);
    double dx = _cairo_fixed_to_double (d->x);
    double dy = _cairo_fixed_to_double (d->y);

    if (info->ctm_inverse) {
	cairo_matrix_transform_point (info->ctm_inverse, &bx, &by);
	cairo_matrix_transform_point (info->ctm_inverse, &cx, &cy);
	cairo_matrix_transform_point (info->ctm_inverse, &dx, &dy);
    }

    _cairo_output_stream_printf (info->output,
				 "%f %f %f %f %f %f c ",
				 bx, by, cx, cy, dx, dy);
    return CAIRO_STATUS_SUCCESS;
}

static cairo_status_t
_cairo_pdf_path_close_path (void *closure)
{
    pdf_path_info_t *info = closure;

    _cairo_output_stream_printf (info->output,
				 "h\r\n");

    return CAIRO_STATUS_SUCCESS;
}

static cairo_int_status_t
_cairo_pdf_surface_intersect_clip_path (void			*abstract_surface,
					cairo_path_fixed_t	*path,
					cairo_fill_rule_t	fill_rule,
					double			tolerance,
					cairo_antialias_t	antialias)
{
    cairo_pdf_surface_t *surface = abstract_surface;
    cairo_status_t status;
    const char *pdf_operator;
    pdf_path_info_t info;

    if (path == NULL) {
	if (surface->has_clip)
	    _cairo_output_stream_printf (surface->output, "Q\r\n");
	surface->has_clip = FALSE;
	return CAIRO_STATUS_SUCCESS;
    }

    if (!surface->has_clip) {
	_cairo_output_stream_printf (surface->output, "q ");
	surface->has_clip = TRUE;
    }

    info.output = surface->output;
    info.ctm_inverse = NULL;

    status = _cairo_path_fixed_interpret (path,
					  CAIRO_DIRECTION_FORWARD,
					  _cairo_pdf_path_move_to,
					  _cairo_pdf_path_line_to,
					  _cairo_pdf_path_curve_to,
					  _cairo_pdf_path_close_path,
					  &info);

    switch (fill_rule) {
    case CAIRO_FILL_RULE_WINDING:
	pdf_operator = "W";
	break;
    case CAIRO_FILL_RULE_EVEN_ODD:
	pdf_operator = "W*";
	break;
    default:
	ASSERT_NOT_REACHED;
    }

    _cairo_output_stream_printf (surface->output,
				 "%s n\r\n",
				 pdf_operator);

    return status;
}

static void
_cairo_pdf_surface_get_font_options (void                  *abstract_surface,
				     cairo_font_options_t  *options)
{
    _cairo_font_options_init_default (options);

    cairo_font_options_set_hint_style (options, CAIRO_HINT_STYLE_NONE);
    cairo_font_options_set_hint_metrics (options, CAIRO_HINT_METRICS_OFF);
}

static cairo_pdf_resource_t
_cairo_pdf_surface_write_info (cairo_pdf_surface_t *surface)
{
    cairo_pdf_resource_t info;

    info = _cairo_pdf_surface_new_object (surface);
    _cairo_output_stream_printf (surface->output,
				 "%d 0 obj\r\n"
				 "<< /Creator (cairographics.org)\r\n"
				 "   /Producer (cairographics.org)\r\n"
				 ">>\r\n"
				 "endobj\r\n",
				 info.id);

    return info;
}

static void
_cairo_pdf_surface_write_pages (cairo_pdf_surface_t *surface)
{
    cairo_pdf_resource_t page, *res;
    cairo_pdf_font_t font;
    int num_pages, num_fonts, i;
    int num_alphas, num_resources;
    double alpha;

    _cairo_pdf_surface_update_object (surface, surface->pages_resource);
    _cairo_output_stream_printf (surface->output,
				 "%d 0 obj\r\n"
				 "<< /Type /Pages\r\n"
				 "   /Kids [ ",
				 surface->pages_resource.id);

    num_pages = _cairo_array_num_elements (&surface->pages);
    for (i = 0; i < num_pages; i++) {
	_cairo_array_copy_element (&surface->pages, i, &page);
	_cairo_output_stream_printf (surface->output, "%d 0 R ", page.id);
    }

    _cairo_output_stream_printf (surface->output, "]\r\n");
    _cairo_output_stream_printf (surface->output, "   /Count %d\r\n", num_pages);

    _cairo_output_stream_printf (surface->output, "   /Resources <<\r\n");

    num_alphas =  _cairo_array_num_elements (&surface->alphas);
    if (num_alphas > 0) {
	_cairo_output_stream_printf (surface->output,
				     "      /ExtGState <<\r\n");

	for (i = 0; i < num_alphas; i++) {
	    /* With some work, we could separate the stroking
	     * or non-stroking alpha here as actually needed. */
	    _cairo_array_copy_element (&surface->alphas, i, &alpha);
	    _cairo_output_stream_printf (surface->output,
					 "         /a%d << /CA %f /ca %f >>\r\n",
					 i, alpha, alpha);
	}

	_cairo_output_stream_printf (surface->output,
				     "      >>\r\n");
    }

    num_resources = _cairo_array_num_elements (&surface->patterns);
    if (num_resources > 0) {
	_cairo_output_stream_printf (surface->output,
				     "      /Pattern <<");
	for (i = 0; i < num_resources; i++) {
	    res = _cairo_array_index (&surface->patterns, i);
	    _cairo_output_stream_printf (surface->output,
					 " /res%d %d 0 R",
					 res->id, res->id);
	}

	_cairo_output_stream_printf (surface->output,
				     " >>\r\n");
    }

    num_resources = _cairo_array_num_elements (&surface->xobjects);
    if (num_resources > 0) {
	_cairo_output_stream_printf (surface->output,
				     "      /XObject <<");

	for (i = 0; i < num_resources; i++) {
	    res = _cairo_array_index (&surface->xobjects, i);
	    _cairo_output_stream_printf (surface->output,
					 " /res%d %d 0 R",
					 res->id, res->id);
	}

	_cairo_output_stream_printf (surface->output,
				     " >>\r\n");
    }

    _cairo_output_stream_printf (surface->output,"      /Font <<\r\n");
    num_fonts = _cairo_array_num_elements (&surface->fonts);
    for (i = 0; i < num_fonts; i++) {
	_cairo_array_copy_element (&surface->fonts, i, &font);
	_cairo_output_stream_printf (surface->output, "         /CairoFont-%d-%d %d 0 R\r\n",
				     font.font_id, font.subset_id, font.subset_resource.id);
    }
    _cairo_output_stream_printf (surface->output, "      >>\r\n");

    _cairo_output_stream_printf (surface->output,
				 "   >>\r\n");

    /* TODO: Figure out wich other defaults to be inherited by /Page
     * objects. */
    _cairo_output_stream_printf (surface->output,
				 ">>\r\n"
				 "endobj\r\n");
}

static cairo_status_t
_cairo_pdf_surface_emit_type1_font_subset (cairo_pdf_surface_t		*surface,
					   cairo_scaled_font_subset_t	*font_subset)
{
    cairo_pdf_resource_t stream, descriptor, subset_resource;
    cairo_status_t status;
    cairo_pdf_font_t font;
    cairo_type1_subset_t subset;
    unsigned long length, compressed_length;
    char *compressed;
    int i;
    char name[64];

    snprintf (name, sizeof name, "CairoFont-%d-%d",
	      font_subset->font_id, font_subset->subset_id);
    status = _cairo_type1_subset_init (&subset, name, font_subset);
    if (status)
	return status;

    /* We ignore the zero-trailer and set Length3 to 0. */
    length = subset.header_length + subset.data_length;
    compressed = compress_dup (subset.data, length, &compressed_length);
    if (compressed == NULL) {
	_cairo_type1_subset_fini (&subset);
	return CAIRO_STATUS_NO_MEMORY;
    }

    stream = _cairo_pdf_surface_new_object (surface);
    _cairo_output_stream_printf (surface->output,
				 "%d 0 obj\r\n"
				 "<< /Filter /FlateDecode\r\n"
				 "   /Length %lu\r\n"
				 "   /Length1 %lu\r\n"
				 "   /Length2 %lu\r\n"
				 "   /Length3 0\r\n"
				 ">>\r\n"
				 "stream\r\n",
				 stream.id,
				 compressed_length,
				 subset.header_length,
				 subset.data_length);
    _cairo_output_stream_write (surface->output, compressed, compressed_length);
    _cairo_output_stream_printf (surface->output,
				 "\r\n"
				 "endstream\r\n"
				 "endobj\r\n");
    free (compressed);

    descriptor = _cairo_pdf_surface_new_object (surface);
    _cairo_output_stream_printf (surface->output,
				 "%d 0 obj\r\n"
				 "<< /Type /FontDescriptor\r\n"
				 "   /FontName /%s\r\n"
				 "   /Flags 4\r\n"
				 "   /FontBBox [ %ld %ld %ld %ld ]\r\n"
				 "   /ItalicAngle 0\r\n"
				 "   /Ascent %ld\r\n"
				 "   /Descent %ld\r\n"
				 "   /CapHeight 500\r\n"
				 "   /StemV 80\r\n"
				 "   /StemH 80\r\n"
				 "   /FontFile %u 0 R\r\n"
				 ">>\r\n"
				 "endobj\r\n",
				 descriptor.id,
				 subset.base_font,
				 subset.x_min,
				 subset.y_min,
				 subset.x_max,
				 subset.y_max,
				 subset.ascent,
				 subset.descent,
				 stream.id);

    subset_resource = _cairo_pdf_surface_new_object (surface);
    _cairo_output_stream_printf (surface->output,
				 "%d 0 obj\r\n"
				 "<< /Type /Font\r\n"
				 "   /Subtype /Type1\r\n"
				 "   /BaseFont /%s\r\n"
				 "   /FirstChar 0\r\n"
				 "   /LastChar %d\r\n"
				 "   /FontDescriptor %d 0 R\r\n"
				 "   /Widths [",
				 subset_resource.id,
				 subset.base_font,
				 font_subset->num_glyphs,
				 descriptor.id);

    for (i = 0; i < font_subset->num_glyphs; i++)
	_cairo_output_stream_printf (surface->output,
				     " %d",
				     subset.widths[i]);

    _cairo_output_stream_printf (surface->output,
				 " ]\r\n"
				 ">>\r\n"
				 "endobj\r\n");

    font.font_id = font_subset->font_id;
    font.subset_id = font_subset->subset_id;
    font.subset_resource = subset_resource;
    _cairo_array_append (&surface->fonts, &font);

    _cairo_type1_subset_fini (&subset);

    return CAIRO_STATUS_SUCCESS;
}

static cairo_status_t
_cairo_pdf_surface_emit_truetype_font_subset (cairo_pdf_surface_t		*surface,
					      cairo_scaled_font_subset_t	*font_subset)
{
    cairo_pdf_resource_t stream, descriptor, subset_resource;
    cairo_status_t status;
    cairo_pdf_font_t font;
    cairo_truetype_subset_t subset;
    unsigned long compressed_length;
    char *compressed;
    int i;

    status = _cairo_truetype_subset_init (&subset, font_subset);
    if (status)
	return status;

    compressed = compress_dup (subset.data, subset.data_length,
			       &compressed_length);
    if (compressed == NULL) {
	_cairo_truetype_subset_fini (&subset);
	return CAIRO_STATUS_NO_MEMORY;
    }

    stream = _cairo_pdf_surface_new_object (surface);
    _cairo_output_stream_printf (surface->output,
				 "%d 0 obj\r\n"
				 "<< /Filter /FlateDecode\r\n"
				 "   /Length %lu\r\n"
				 "   /Length1 %lu\r\n"
				 ">>\r\n"
				 "stream\r\n",
				 stream.id,
				 compressed_length,
				 subset.data_length);
    _cairo_output_stream_write (surface->output, compressed, compressed_length);
    _cairo_output_stream_printf (surface->output,
				 "\r\n"
				 "endstream\r\n"
				 "endobj\r\n");
    free (compressed);

    descriptor = _cairo_pdf_surface_new_object (surface);
    _cairo_output_stream_printf (surface->output,
				 "%d 0 obj\r\n"
				 "<< /Type /FontDescriptor\r\n"
				 "   /FontName /7%s\r\n"
				 "   /Flags 4\r\n"
				 "   /FontBBox [ %ld %ld %ld %ld ]\r\n"
				 "   /ItalicAngle 0\r\n"
				 "   /Ascent %ld\r\n"
				 "   /Descent %ld\r\n"
				 "   /CapHeight 500\r\n"
				 "   /StemV 80\r\n"
				 "   /StemH 80\r\n"
				 "   /FontFile2 %u 0 R\r\n"
				 ">>\r\n"
				 "endobj\r\n",
				 descriptor.id,
				 subset.base_font,
				 subset.x_min,
				 subset.y_min,
				 subset.x_max,
				 subset.y_max,
				 subset.ascent,
				 subset.descent,
				 stream.id);