mirror of
https://gitlab.freedesktop.org/cairo/cairo.git
synced 2026-01-03 11:40:21 +01:00
pdf: use cross-reference stream for PDF >= 1.5
This reduces the output size and is required for object streams.
This commit is contained in:
Adrian Johnson
parent
d6fefd3156
commit
0f382eb087
2 changed files with 174 additions and 24 deletions
|
|
@ -288,7 +288,7 @@ struct _cairo_pdf_surface {
|
|||
cairo_pdf_resource_t struct_tree_root;
|
||||
|
||||
cairo_pdf_version_t pdf_version;
|
||||
cairo_bool_t compress_content;
|
||||
cairo_bool_t compress_streams;
|
||||
|
||||
cairo_pdf_resource_t content;
|
||||
cairo_pdf_resource_t content_resources;
|
||||
|
|
|
|||
|
|
@ -285,6 +285,13 @@ _cairo_pdf_surface_write_catalog (cairo_pdf_surface_t *surface);
|
|||
static long
|
||||
_cairo_pdf_surface_write_xref (cairo_pdf_surface_t *surface);
|
||||
|
||||
static cairo_int_status_t
|
||||
_cairo_pdf_surface_write_xref_stream (cairo_pdf_surface_t *surface,
|
||||
cairo_pdf_resource_t xref_res,
|
||||
cairo_pdf_resource_t root_res,
|
||||
cairo_pdf_resource_t info_res,
|
||||
long *xref_offset);
|
||||
|
||||
static cairo_int_status_t
|
||||
_cairo_pdf_surface_write_patterns_and_smask_groups (cairo_pdf_surface_t *surface,
|
||||
cairo_bool_t finish);
|
||||
|
|
@ -459,7 +466,7 @@ _cairo_pdf_surface_create_for_stream_internal (cairo_output_stream_t *output,
|
|||
|
||||
surface->struct_tree_root.id = 0;
|
||||
surface->pdf_version = CAIRO_PDF_VERSION_1_5;
|
||||
surface->compress_content = TRUE;
|
||||
surface->compress_streams = TRUE;
|
||||
surface->pdf_stream.active = FALSE;
|
||||
surface->pdf_stream.old_output = NULL;
|
||||
surface->group_stream.active = FALSE;
|
||||
|
|
@ -506,7 +513,7 @@ _cairo_pdf_surface_create_for_stream_internal (cairo_output_stream_t *output,
|
|||
surface->thumbnail_image = NULL;
|
||||
|
||||
if (getenv ("CAIRO_DEBUG_PDF") != NULL)
|
||||
surface->compress_content = FALSE;
|
||||
surface->compress_streams = FALSE;
|
||||
|
||||
surface->paginated_surface = _cairo_paginated_surface_create (
|
||||
&surface->base,
|
||||
|
|
@ -1954,7 +1961,7 @@ _cairo_pdf_surface_write_memory_stream (cairo_pdf_surface_t *surface,
|
|||
resource.id,
|
||||
_cairo_memory_stream_length (mem_stream));
|
||||
|
||||
if (surface->compress_content) {
|
||||
if (surface->compress_streams) {
|
||||
_cairo_output_stream_printf (surface->output,
|
||||
" /Filter /FlateDecode\n");
|
||||
}
|
||||
|
|
@ -2003,7 +2010,7 @@ _cairo_pdf_surface_open_group (cairo_pdf_surface_t *surface,
|
|||
|
||||
surface->group_stream.mem_stream = _cairo_memory_stream_create ();
|
||||
|
||||
if (surface->compress_content) {
|
||||
if (surface->compress_streams) {
|
||||
surface->group_stream.stream =
|
||||
_cairo_deflate_stream_create (surface->group_stream.mem_stream);
|
||||
} else {
|
||||
|
|
@ -2057,7 +2064,7 @@ _cairo_pdf_surface_close_group (cairo_pdf_surface_t *surface,
|
|||
if (unlikely (status))
|
||||
return status;
|
||||
|
||||
if (surface->compress_content) {
|
||||
if (surface->compress_streams) {
|
||||
status = _cairo_output_stream_destroy (surface->group_stream.stream);
|
||||
surface->group_stream.stream = NULL;
|
||||
|
||||
|
|
@ -2109,7 +2116,7 @@ _cairo_pdf_surface_open_content_stream (cairo_pdf_surface_t *surface,
|
|||
status =
|
||||
_cairo_pdf_surface_open_stream (surface,
|
||||
resource,
|
||||
surface->compress_content,
|
||||
surface->compress_streams,
|
||||
" /Type /XObject\n"
|
||||
" /Subtype /Form\n"
|
||||
" /BBox [ %f %f %f %f ]\n"
|
||||
|
|
@ -2129,7 +2136,7 @@ _cairo_pdf_surface_open_content_stream (cairo_pdf_surface_t *surface,
|
|||
status =
|
||||
_cairo_pdf_surface_open_stream (surface,
|
||||
resource,
|
||||
surface->compress_content,
|
||||
surface->compress_streams,
|
||||
" /Type /XObject\n"
|
||||
" /Subtype /Form\n"
|
||||
" /BBox [ %f %f %f %f ]\n"
|
||||
|
|
@ -2144,7 +2151,7 @@ _cairo_pdf_surface_open_content_stream (cairo_pdf_surface_t *surface,
|
|||
status =
|
||||
_cairo_pdf_surface_open_stream (surface,
|
||||
resource,
|
||||
surface->compress_content,
|
||||
surface->compress_streams,
|
||||
NULL);
|
||||
_cairo_output_stream_printf (surface->output,
|
||||
"1 0 0 -1 0 %f cm\n",
|
||||
|
|
@ -2212,6 +2219,7 @@ _cairo_pdf_surface_finish (void *abstract_surface)
|
|||
cairo_pdf_source_surface_t doc_surface;
|
||||
cairo_pdf_jbig2_global_t *global;
|
||||
char *label;
|
||||
cairo_pdf_resource_t xref_res;
|
||||
|
||||
_cairo_pdf_surface_clear (surface);
|
||||
|
||||
|
|
@ -2232,18 +2240,26 @@ _cairo_pdf_surface_finish (void *abstract_surface)
|
|||
if (catalog.id == 0 && status == CAIRO_STATUS_SUCCESS)
|
||||
status = _cairo_error (CAIRO_STATUS_NO_MEMORY);
|
||||
|
||||
offset = _cairo_pdf_surface_write_xref (surface);
|
||||
|
||||
_cairo_output_stream_printf (surface->output,
|
||||
"trailer\n"
|
||||
"<< /Size %d\n"
|
||||
" /Root %d 0 R\n"
|
||||
" /Info %d 0 R\n"
|
||||
">>\n",
|
||||
surface->next_available_resource.id,
|
||||
catalog.id,
|
||||
surface->docinfo_res.id);
|
||||
|
||||
if (surface->pdf_version >= CAIRO_PDF_VERSION_1_5)
|
||||
{
|
||||
xref_res = _cairo_pdf_surface_new_object (surface);
|
||||
status = _cairo_pdf_surface_write_xref_stream (surface,
|
||||
xref_res,
|
||||
catalog,
|
||||
surface->docinfo_res,
|
||||
&offset);
|
||||
} else {
|
||||
offset = _cairo_pdf_surface_write_xref (surface);
|
||||
_cairo_output_stream_printf (surface->output,
|
||||
"trailer\n"
|
||||
"<< /Size %d\n"
|
||||
" /Root %d 0 R\n"
|
||||
" /Info %d 0 R\n"
|
||||
">>\n",
|
||||
surface->next_available_resource.id,
|
||||
catalog.id,
|
||||
surface->docinfo_res.id);
|
||||
}
|
||||
_cairo_output_stream_printf (surface->output,
|
||||
"startxref\n"
|
||||
"%ld\n"
|
||||
|
|
@ -4223,7 +4239,7 @@ cairo_pdf_surface_emit_transparency_group (cairo_pdf_surface_t *surface,
|
|||
}
|
||||
status = _cairo_pdf_surface_open_stream (surface,
|
||||
NULL,
|
||||
surface->compress_content,
|
||||
surface->compress_streams,
|
||||
" /Type /XObject\n"
|
||||
" /Subtype /Form\n"
|
||||
" /FormType 1\n"
|
||||
|
|
@ -5338,7 +5354,7 @@ _cairo_pdf_surface_emit_to_unicode_stream (cairo_pdf_surface_t *surface,
|
|||
|
||||
status = _cairo_pdf_surface_open_stream (surface,
|
||||
NULL,
|
||||
surface->compress_content,
|
||||
surface->compress_streams,
|
||||
NULL);
|
||||
if (unlikely (status))
|
||||
return status;
|
||||
|
|
@ -6221,7 +6237,7 @@ _cairo_pdf_surface_emit_type3_font_subset (cairo_pdf_surface_t *surface,
|
|||
for (i = 0; i < font_subset->num_glyphs; i++) {
|
||||
status = _cairo_pdf_surface_open_stream (surface,
|
||||
NULL,
|
||||
surface->compress_content,
|
||||
surface->compress_streams,
|
||||
NULL);
|
||||
if (unlikely (status))
|
||||
break;
|
||||
|
|
@ -6515,6 +6531,140 @@ _cairo_pdf_surface_write_xref (cairo_pdf_surface_t *surface)
|
|||
return offset;
|
||||
}
|
||||
|
||||
static void
|
||||
_cairo_write_xref_stream_entry (cairo_output_stream_t *stream,
|
||||
int id,
|
||||
int type,
|
||||
int field2_size,
|
||||
long field2,
|
||||
int field3,
|
||||
cairo_bool_t write_as_comments)
|
||||
{
|
||||
char buf[20];
|
||||
int i;
|
||||
|
||||
if (write_as_comments) {
|
||||
_cairo_output_stream_printf (stream, "%% %5d %2d %10ld %d\n", id, type, field2, field3);
|
||||
} else {
|
||||
/* Each field is big endian */
|
||||
buf[0] = type; /* field 1 */
|
||||
for (i = field2_size - 1; i >= 0; i--) {
|
||||
buf[i + 1] = field2 & 0xff;
|
||||
field2 >>= 8;
|
||||
}
|
||||
buf[field2_size + 1] = field3 >> 8;
|
||||
buf[field2_size + 2] = field3 & 0xff;
|
||||
_cairo_output_stream_write (stream, buf, field2_size + 3);
|
||||
}
|
||||
}
|
||||
|
||||
static void
|
||||
_cairo_write_xref_stream_entrys (cairo_pdf_surface_t *surface,
|
||||
cairo_output_stream_t *stream,
|
||||
int field2_size,
|
||||
cairo_bool_t write_as_comments)
|
||||
{
|
||||
cairo_pdf_object_t *object;
|
||||
int num_objects, i;
|
||||
|
||||
/* PDF requires this to be first entry */
|
||||
_cairo_write_xref_stream_entry (stream,
|
||||
0,
|
||||
0, /* type 0 == free */
|
||||
field2_size,
|
||||
0, /* next free object number */
|
||||
0xffff, /* next generation number */
|
||||
write_as_comments);
|
||||
|
||||
num_objects = _cairo_array_num_elements (&surface->objects);
|
||||
for (i = 0; i < num_objects; i++) {
|
||||
object = _cairo_array_index (&surface->objects, i);
|
||||
_cairo_write_xref_stream_entry (stream,
|
||||
i + 1,
|
||||
1, /* type 1 == in use, not in obj stream */
|
||||
field2_size,
|
||||
object->offset,
|
||||
0, /* generation number */
|
||||
write_as_comments);
|
||||
}
|
||||
}
|
||||
|
||||
static cairo_int_status_t
|
||||
_cairo_pdf_surface_write_xref_stream (cairo_pdf_surface_t *surface,
|
||||
cairo_pdf_resource_t xref_res,
|
||||
cairo_pdf_resource_t root_res,
|
||||
cairo_pdf_resource_t info_res,
|
||||
long *xref_offset)
|
||||
{
|
||||
cairo_output_stream_t *mem_stream;
|
||||
cairo_output_stream_t *xref_stream;
|
||||
long offset;
|
||||
int offset_bytes;
|
||||
cairo_status_t status;
|
||||
|
||||
*xref_offset = _cairo_output_stream_get_position (surface->output);
|
||||
|
||||
/* Find the minimum number of bytes required to represent offsets in the generated file (up to this point). */
|
||||
offset_bytes = 0;
|
||||
offset = *xref_offset;
|
||||
while (offset > 0) {
|
||||
offset >>= 8;
|
||||
offset_bytes++;
|
||||
}
|
||||
|
||||
mem_stream = _cairo_memory_stream_create ();
|
||||
xref_stream = _cairo_deflate_stream_create (mem_stream);
|
||||
|
||||
_cairo_write_xref_stream_entrys (surface, xref_stream, offset_bytes, FALSE);
|
||||
|
||||
status = _cairo_output_stream_destroy (xref_stream);
|
||||
if (unlikely (status))
|
||||
return status;
|
||||
|
||||
_cairo_pdf_surface_update_object (surface, xref_res);
|
||||
_cairo_output_stream_printf (surface->output,
|
||||
"%d 0 obj\n"
|
||||
"<< /Type /XRef\n"
|
||||
" /Length %d\n"
|
||||
" /Filter /FlateDecode\n"
|
||||
" /Size %d\n"
|
||||
" /W [1 %d 2]\n"
|
||||
" /Root %d 0 R\n"
|
||||
" /Info %d 0 R\n"
|
||||
">>\n",
|
||||
xref_res.id,
|
||||
_cairo_memory_stream_length (mem_stream),
|
||||
surface->next_available_resource.id,
|
||||
offset_bytes,
|
||||
root_res.id,
|
||||
info_res.id);
|
||||
|
||||
if (!surface->compress_streams) {
|
||||
/* Adobe Reader requires xref streams to be flate encoded (PDF
|
||||
* Reference 1.7, implemenation note 20). This means
|
||||
* compression must always be enabled on this stream. To
|
||||
* facilitate debugging when compress_stream is disabled, emit
|
||||
* a human readable format of the xref stream as PDF comments.
|
||||
*/
|
||||
_cairo_output_stream_printf (surface->output,
|
||||
"%% id type offset gen\n");
|
||||
_cairo_write_xref_stream_entrys (surface, surface->output, offset_bytes, TRUE);
|
||||
}
|
||||
|
||||
_cairo_output_stream_printf (surface->output,
|
||||
"stream\n");
|
||||
_cairo_memory_stream_copy (mem_stream, surface->output);
|
||||
status = _cairo_output_stream_destroy (mem_stream);
|
||||
if (unlikely (status))
|
||||
return status;
|
||||
|
||||
_cairo_output_stream_printf (surface->output,
|
||||
"\nendstream\n"
|
||||
"endobj\n");
|
||||
|
||||
return _cairo_output_stream_get_status (surface->output);
|
||||
}
|
||||
|
||||
static cairo_int_status_t
|
||||
_cairo_pdf_surface_write_mask_group (cairo_pdf_surface_t *surface,
|
||||
cairo_pdf_smask_group_t *group)
|
||||
|
|
|
|||
Loading…
Add table
Reference in a new issue