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

    subset_resource = _cairo_pdf_surface_new_object (surface);
    _cairo_output_stream_printf (surface->output,
				 "%d 0 obj\r\n"
				 "<< /Type /Font\r\n"
				 "   /Subtype /TrueType\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_truetype_subset_fini (&subset);

    return CAIRO_STATUS_SUCCESS;
}

static cairo_int_status_t
_cairo_pdf_surface_emit_outline_glyph (cairo_pdf_surface_t	*surface,
				       cairo_scaled_font_t	*scaled_font,
				       unsigned long		 glyph_index,
				       cairo_pdf_resource_t	*glyph_ret)
{
    cairo_scaled_glyph_t *scaled_glyph;
    pdf_path_info_t info;
    cairo_status_t status = CAIRO_STATUS_SUCCESS;

    status = _cairo_scaled_glyph_lookup (scaled_font,
					 glyph_index,
					 CAIRO_SCALED_GLYPH_INFO_METRICS|
					 CAIRO_SCALED_GLYPH_INFO_PATH,
					 &scaled_glyph);
    if (status)
	return status;

    *glyph_ret = _cairo_pdf_surface_open_stream (surface, NULL);

    _cairo_output_stream_printf (surface->output,
				 "0 0 %f %f %f %f d1\r\n",
				 _cairo_fixed_to_double (scaled_glyph->bbox.p1.x),
				 -_cairo_fixed_to_double (scaled_glyph->bbox.p2.y),
				 _cairo_fixed_to_double (scaled_glyph->bbox.p2.x),
				 -_cairo_fixed_to_double (scaled_glyph->bbox.p1.y));

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

    status = _cairo_path_fixed_interpret (scaled_glyph->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);

    _cairo_output_stream_printf (surface->output,
				 " f");

    _cairo_pdf_surface_close_stream (surface);

    return CAIRO_STATUS_SUCCESS;
}

static cairo_int_status_t
_cairo_pdf_surface_emit_bitmap_glyph (cairo_pdf_surface_t	*surface,
				      cairo_scaled_font_t	*scaled_font,
				      unsigned long		 glyph_index,
				      cairo_pdf_resource_t	*glyph_ret)
{
    cairo_scaled_glyph_t *scaled_glyph;
    cairo_status_t status;
    cairo_image_surface_t *image;
    unsigned char *row, *byte;
    int rows, cols, bytes_per_row;

    status = _cairo_scaled_glyph_lookup (scaled_font,
					 glyph_index,
					 CAIRO_SCALED_GLYPH_INFO_METRICS|
					 CAIRO_SCALED_GLYPH_INFO_SURFACE,
					 &scaled_glyph);
    if (status)
	return status;

    image = scaled_glyph->surface;
    assert (image->format == CAIRO_FORMAT_A1);

    *glyph_ret = _cairo_pdf_surface_open_stream (surface, NULL);

    _cairo_output_stream_printf (surface->output,
				 "0 0 %f %f %f %f d1\r\n",
				 _cairo_fixed_to_double (scaled_glyph->bbox.p1.x),
				 - _cairo_fixed_to_double (scaled_glyph->bbox.p2.y),
				 _cairo_fixed_to_double (scaled_glyph->bbox.p2.x),
				 - _cairo_fixed_to_double (scaled_glyph->bbox.p1.y));

    _cairo_output_stream_printf (surface->output,
				 "%f 0.0 0.0 %f %f %f cm\r\n",
				 _cairo_fixed_to_double (scaled_glyph->bbox.p2.x) - _cairo_fixed_to_double (scaled_glyph->bbox.p1.x),
				 _cairo_fixed_to_double (scaled_glyph->bbox.p1.y) - _cairo_fixed_to_double (scaled_glyph->bbox.p2.y),
				 _cairo_fixed_to_double (scaled_glyph->bbox.p1.x),
				 _cairo_fixed_to_double (scaled_glyph->bbox.p2.y));

    _cairo_output_stream_printf (surface->output,
				 "BI\r\n"
				 "/IM true\r\n"
				 "/W %d\r\n"
				 "/H %d\r\n"
				 "/BPC 1\r\n"
				 "/D [1 0]\r\n",
				 image->width,
				 image->height);

    _cairo_output_stream_printf (surface->output,
				 "ID ");
    bytes_per_row = (image->width + 7) / 8;
    for (row = image->data, rows = image->height; rows; row += image->stride, rows--) {
	for (byte = row, cols = (image->width + 7) / 8; cols; byte++, cols--) {
	    unsigned char output_byte = CAIRO_BITSWAP8_IF_LITTLE_ENDIAN (*byte);
	    _cairo_output_stream_write (surface->output, &output_byte, 1);
	}
    }
    _cairo_output_stream_printf (surface->output,
				 "\r\nEI\r\n");

    _cairo_pdf_surface_close_stream (surface);

    return CAIRO_STATUS_SUCCESS;
}

static void
_cairo_pdf_surface_emit_glyph (cairo_pdf_surface_t	*surface,
			       cairo_scaled_font_t	*scaled_font,
			       unsigned long		 glyph_index,
			       cairo_pdf_resource_t	*glyph_ret)
{
    cairo_status_t status;

    status = _cairo_pdf_surface_emit_outline_glyph (surface,
						    scaled_font,
						    glyph_index,
						    glyph_ret);
    if (status == CAIRO_INT_STATUS_UNSUPPORTED)
	status = _cairo_pdf_surface_emit_bitmap_glyph (surface,
						       scaled_font,
						       glyph_index,
						       glyph_ret);

    if (status)
	_cairo_surface_set_error (&surface->base, status);
}

static cairo_status_t
_cairo_pdf_surface_emit_type3_font_subset (cairo_pdf_surface_t		*surface,
					   cairo_scaled_font_subset_t	*font_subset)
{
    cairo_pdf_resource_t *glyphs, encoding, char_procs, subset_resource;
    cairo_pdf_font_t font;
    cairo_matrix_t matrix;
    int i;

    glyphs = malloc (font_subset->num_glyphs * sizeof (cairo_pdf_resource_t));
    if (glyphs == NULL) {
	_cairo_surface_set_error (&surface->base, CAIRO_STATUS_NO_MEMORY);
	return CAIRO_STATUS_NO_MEMORY;
    }

    for (i = 0; i < font_subset->num_glyphs; i++) {
	_cairo_pdf_surface_emit_glyph (surface,
				       font_subset->scaled_font,
				       font_subset->glyphs[i],
				       &glyphs[i]);
    }

    encoding = _cairo_pdf_surface_new_object (surface);
    _cairo_output_stream_printf (surface->output,
				 "%d 0 obj\r\n"
				 "<< /Type /Encoding\r\n"
				 "   /Differences [0", encoding.id);
    for (i = 0; i < font_subset->num_glyphs; i++)
	_cairo_output_stream_printf (surface->output,
				     " /%d", i);
    _cairo_output_stream_printf (surface->output,
				 "]\r\n"
				 ">>\r\n"
				 "endobj\r\n");

    char_procs = _cairo_pdf_surface_new_object (surface);
    _cairo_output_stream_printf (surface->output,
				 "%d 0 obj\r\n"
				 "<<\r\n", char_procs.id);
    for (i = 0; i < font_subset->num_glyphs; i++)
	_cairo_output_stream_printf (surface->output,
				     " /%d %d 0 R\r\n",
				     i, glyphs[i].id);
    _cairo_output_stream_printf (surface->output,
				 ">>\r\n"
				 "endobj\r\n");

    subset_resource = _cairo_pdf_surface_new_object (surface);
    matrix = font_subset->scaled_font->scale;
    cairo_matrix_invert (&matrix);
    _cairo_output_stream_printf (surface->output,
				 "%d 0 obj\r\n"
				 "<< /Type /Font\r\n"
				 "   /Subtype /Type3\r\n"
				 "   /FontBBox [0 0 0 0]\r\n"
				 "   /FontMatrix [ %f %f %f %f 0 0 ]\r\n"
				 "   /Encoding %d 0 R\r\n"
				 "   /CharProcs %d 0 R\r\n"
				 "   /FirstChar 0\r\n"
				 "   /LastChar %d\r\n",
				 subset_resource.id,
				 matrix.xx,
				 matrix.yx,
				 -matrix.xy,
				 -matrix.yy,
				 encoding.id,
				 char_procs.id,
				 font_subset->num_glyphs - 1);

    _cairo_output_stream_printf (surface->output,
				 "   /Widths [");
    for (i = 0; i < font_subset->num_glyphs; i++)
	_cairo_output_stream_printf (surface->output, " 0");
    _cairo_output_stream_printf (surface->output,
				 "]\r\n");

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

    return CAIRO_STATUS_SUCCESS;
}

static void
_cairo_pdf_surface_emit_font_subset (cairo_scaled_font_subset_t	*font_subset,
				     void			*closure)
{
    cairo_pdf_surface_t *surface = closure;
    cairo_status_t status;

    status = _cairo_pdf_surface_emit_type1_font_subset (surface, font_subset);
    if (status != CAIRO_INT_STATUS_UNSUPPORTED)
	return;

    status = _cairo_pdf_surface_emit_truetype_font_subset (surface, font_subset);
    if (status != CAIRO_INT_STATUS_UNSUPPORTED)
	return;

    status = _cairo_pdf_surface_emit_type3_font_subset (surface, font_subset);
    if (status != CAIRO_INT_STATUS_UNSUPPORTED)
	return;
}

static cairo_status_t
_cairo_pdf_surface_emit_font_subsets (cairo_pdf_surface_t *surface)
{
    cairo_status_t status;

    status = _cairo_scaled_font_subsets_foreach (surface->font_subsets,
						 _cairo_pdf_surface_emit_font_subset,
						 surface);
    _cairo_scaled_font_subsets_destroy (surface->font_subsets);
    surface->font_subsets = NULL;

    if (status)
	return status;

    return CAIRO_STATUS_SUCCESS;
}

#if 0
static cairo_status_t
_cairo_pdf_surface_write_fonts (cairo_pdf_surface_t *surface)
{
    cairo_font_subset_t *font;
    cairo_pdf_resource_t font_resource;
    int num_fonts, i, j;
    const char *data;
    char *compressed;
    unsigned long data_size, compressed_size;
    cairo_pdf_resource_t stream, descriptor;
    cairo_status_t status = CAIRO_STATUS_SUCCESS;

    num_fonts = _cairo_array_num_elements (&surface->fonts);
    for (i = 0; i < num_fonts; i++) {
	_cairo_array_copy_element (&surface->fonts, i, &font);

	status = _cairo_font_subset_generate (font, &data, &data_size);
	if (status)
	    goto fail;

	compressed = compress_dup (data, data_size, &compressed_size);
	if (compressed == NULL) {
	    status = CAIRO_STATUS_NO_MEMORY;
	    goto fail;
	}

	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_size,
				     data_size);
	_cairo_output_stream_write (surface->output, compressed, compressed_size);
	_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,
				     font->base_font,
				     font->x_min,
				     font->y_min,
				     font->x_max,
				     font->y_max,
				     font->ascent,
				     font->descent,
				     stream.id);

	font_resource.id = font->font_id;
	_cairo_pdf_surface_update_object (surface, font_resource);
	_cairo_output_stream_printf (surface->output,
				     "%d 0 obj\r\n"
				     "<< /Type /Font\r\n"
				     "   /Subtype /TrueType\r\n"
				     "   /BaseFont /%s\r\n"
				     "   /FirstChar 0\r\n"
				     "   /LastChar %d\r\n"
				     "   /FontDescriptor %d 0 R\r\n"
				     "   /Widths ",
				     font->font_id,
				     font->base_font,
				     font->num_glyphs,
				     descriptor.id);

	_cairo_output_stream_printf (surface->output,
				     "[");

	for (j = 0; j < font->num_glyphs; j++)
	    _cairo_output_stream_printf (surface->output,
					 " %d",
					 font->widths[j]);

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

    fail:
	_cairo_font_subset_destroy (font);
    }

    return status;
}
#endif

static cairo_pdf_resource_t
_cairo_pdf_surface_write_catalog (cairo_pdf_surface_t *surface)
{
    cairo_pdf_resource_t catalog;

    catalog = _cairo_pdf_surface_new_object (surface);
    _cairo_output_stream_printf (surface->output,
				 "%d 0 obj\r\n"
				 "<< /Type /Catalog\r\n"
				 "   /Pages %d 0 R\r\n"
				 ">>\r\n"
				 "endobj\r\n",
				 catalog.id,
				 surface->pages_resource.id);

    return catalog;
}

static long
_cairo_pdf_surface_write_xref (cairo_pdf_surface_t *surface)
{
    cairo_pdf_object_t *object;
    int num_objects, i;
    long offset;
    char buffer[11];

    num_objects = _cairo_array_num_elements (&surface->objects);

    offset = _cairo_output_stream_get_position (surface->output);
    _cairo_output_stream_printf (surface->output,
				 "xref\r\n"
				 "%d %d\r\n",
				 0, num_objects + 1);

    _cairo_output_stream_printf (surface->output,