Attachment 10631 Details for Bug 10849 – Fix a bug that would cause truetype subsetting to fail on valid fonts.

[patch] Fix a bug that would cause truetype subsetting to fail on valid fonts.

0001-Truetype-Subsetting-Avoid-failing-when-fonts-are-missing-optional-tables.txt (text/plain), 10.24 KB, created by Adrian Johnson on 2007-07-09 05:57:09 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Adrian Johnson

Created: 2007-07-09 05:57:09 UTC

Size: 10.24 KB

patch

obsolete

>From c182d09fb9d2bbb9d88fc983220d047122199ec2 Mon Sep 17 00:00:00 2001
>From: Adrian Johnson <ajohnson@redneon.com>
>Date: Mon, 9 Jul 2007 22:20:45 +0930
>Subject: [PATCH] Truetype Subsetting: Avoid failing when fonts are missing optional tables
>
>Previously, the TrueType subsetting would fail if any of the "cvt",
>"fpgm", or "prep" tables were missing from the source font. However
>these tables are optional and not required in the subsetted font if
>they do not appear in the source font.
>
>The "name" table has been removed from the subsetted font as the
>Type42 specification does not require this table.
>---
> src/cairo-truetype-subset.c |  153 +++++++++++++++++++++++++++++++------------
> 1 files changed, 110 insertions(+), 43 deletions(-)
>
>diff --git a/src/cairo-truetype-subset.c b/src/cairo-truetype-subset.c
>index 7f168a5..1efa4c8 100644
>--- a/src/cairo-truetype-subset.c
>+++ b/src/cairo-truetype-subset.c
>@@ -46,10 +46,22 @@ struct subset_glyph {
>     unsigned long location;
> };
> 
>-typedef struct _cairo_truetype_font {
>+typedef struct _cairo_truetype_font cairo_truetype_font_t;
>+
>+typedef struct table table_t;
>+struct table {
>+    unsigned long tag;
>+    cairo_status_t (*write) (cairo_truetype_font_t *font, unsigned long tag);
>+    int pos; /* position in the font directory */
>+};
>+
>+struct _cairo_truetype_font {
> 
>     cairo_scaled_font_subset_t *scaled_font_subset;
> 
>+    table_t truetype_tables[10];
>+    int num_tables;
>+
>     struct {
> 	char *base_font;
> 	unsigned int num_glyphs;
>@@ -70,7 +82,7 @@ typedef struct _cairo_truetype_font {
>     int *parent_to_subset;
>     cairo_status_t status;
> 
>-} cairo_truetype_font_t;
>+};
> 
> static int
> cairo_truetype_font_use_glyph (cairo_truetype_font_t *font, int glyph);
>@@ -712,35 +724,6 @@ cairo_truetype_font_write_maxp_table (ca
>     return font->status;
> }
> 
>-typedef struct table table_t;
>-struct table {
>-    unsigned long tag;
>-    cairo_status_t (*write) (cairo_truetype_font_t *font, unsigned long tag);
>-    int pos; /* position in the font directory */
>-};
>-
>-static const table_t truetype_tables[] = {
>-    /* As we write out the glyf table we remap composite glyphs.
>-     * Remapping composite glyphs will reference the sub glyphs the
>-     * composite glyph is made up of.  That needs to be done first so
>-     * we have all the glyphs in the subset before going further.
>-     *
>-     * The third column in this table is the order in which the
>-     * directory entries will appear in the table directory.
>-     * The table directory must be sorted in tag order. */
>-    { TT_TAG_glyf, cairo_truetype_font_write_glyf_table,     3 },
>-    { TT_TAG_cmap, cairo_truetype_font_write_cmap_table,     0 },
>-    { TT_TAG_cvt,  cairo_truetype_font_write_generic_table,  1 },
>-    { TT_TAG_fpgm, cairo_truetype_font_write_generic_table,  2 },
>-    { TT_TAG_head, cairo_truetype_font_write_head_table,     4 },
>-    { TT_TAG_hhea, cairo_truetype_font_write_hhea_table,     5 },
>-    { TT_TAG_hmtx, cairo_truetype_font_write_hmtx_table,     6 },
>-    { TT_TAG_loca, cairo_truetype_font_write_loca_table,     7 },
>-    { TT_TAG_maxp, cairo_truetype_font_write_maxp_table,     8 },
>-    { TT_TAG_name, cairo_truetype_font_write_generic_table,  9 },
>-    { TT_TAG_prep, cairo_truetype_font_write_generic_table, 10 },
>-};
>-
> static cairo_status_t
> cairo_truetype_font_write_offset_table (cairo_truetype_font_t *font)
> {
>@@ -748,20 +731,18 @@ cairo_truetype_font_write_offset_table (
>     unsigned char *table_buffer;
>     size_t table_buffer_length;
>     unsigned short search_range, entry_selector, range_shift;
>-    int num_tables;
> 
>-    num_tables = ARRAY_LENGTH (truetype_tables);
>     search_range = 1;
>     entry_selector = 0;
>-    while (search_range * 2 <= num_tables) {
>+    while (search_range * 2 <= font->num_tables) {
> 	search_range *= 2;
> 	entry_selector++;
>     }
>     search_range *= 16;
>-    range_shift = num_tables * 16 - search_range;
>+    range_shift = font->num_tables * 16 - search_range;
> 
>     cairo_truetype_font_write_be32 (font, SFNT_VERSION);
>-    cairo_truetype_font_write_be16 (font, num_tables);
>+    cairo_truetype_font_write_be16 (font, font->num_tables);
>     cairo_truetype_font_write_be16 (font, search_range);
>     cairo_truetype_font_write_be16 (font, entry_selector);
>     cairo_truetype_font_write_be16 (font, range_shift);
>@@ -769,7 +750,7 @@ cairo_truetype_font_write_offset_table (
>     /* Allocate space for the table directory. Each directory entry
>      * will be filled in by cairo_truetype_font_update_entry() after
>      * the table is written. */
>-    table_buffer_length = ARRAY_LENGTH (truetype_tables) * 16;
>+    table_buffer_length = font->num_tables * 16;
>     status = cairo_truetype_font_allocate_write_buffer (font, table_buffer_length,
> 						      &table_buffer);
>     if (status)
>@@ -824,7 +805,7 @@ cairo_truetype_font_generate (cairo_true
>     cairo_status_t status;
>     unsigned long start, end, next;
>     uint32_t checksum, *checksum_location;
>-    unsigned int i;
>+    int i;
> 
>     if (cairo_truetype_font_write_offset_table (font))
> 	goto fail;
>@@ -833,14 +814,14 @@ cairo_truetype_font_generate (cairo_true
>     end = start;
> 
>     end = 0;
>-    for (i = 0; i < ARRAY_LENGTH (truetype_tables); i++) {
>-	if (truetype_tables[i].write (font, truetype_tables[i].tag))
>+    for (i = 0; i < font->num_tables; i++) {
>+	if (font->truetype_tables[i].write (font, font->truetype_tables[i].tag))
> 	    goto fail;
> 
> 	end = _cairo_array_num_elements (&font->output);
> 	next = cairo_truetype_font_align_output (font);
>-	cairo_truetype_font_update_entry (font, truetype_tables[i].pos, truetype_tables[i].tag,
>-					start, end);
>+	cairo_truetype_font_update_entry (font, font->truetype_tables[i].pos,
>+                                          font->truetype_tables[i].tag, start, end);
>         status = cairo_truetype_font_check_boundary (font, next);
> 	if (status) {
> 	    font->status = status;
>@@ -879,6 +860,91 @@ cairo_truetype_font_use_glyph (cairo_tru
>     return font->parent_to_subset[glyph];
> }
> 
>+static void
>+cairo_truetype_font_add_truetype_table (cairo_truetype_font_t *font,
>+           unsigned long tag,
>+           cairo_status_t (*write) (cairo_truetype_font_t *font, unsigned long tag),
>+           int pos)
>+{
>+    font->truetype_tables[font->num_tables].tag = tag;
>+    font->truetype_tables[font->num_tables].write = write;
>+    font->truetype_tables[font->num_tables].pos = pos;
>+    font->num_tables++;
>+}
>+
>+/* cairo_truetype_font_create_truetype_table_list() builds the list of
>+ * truetype tables to be embedded in the subsetted font. Each call to
>+ * cairo_truetype_font_add_truetype_table() adds a table, the callback
>+ * for generating the table, and the position in the table directory
>+ * to the truetype_tables array.
>+ *
>+ * As we write out the glyf table we remap composite glyphs.
>+ * Remapping composite glyphs will reference the sub glyphs the
>+ * composite glyph is made up of. The "glyf" table callback needs to
>+ * be called first so we have all the glyphs in the subset before
>+ * going further.
>+ *
>+ * The order in which tables are added to the truetype_table array
>+ * using cairo_truetype_font_add_truetype_table() specifies the order
>+ * in which the callback functions will be called.
>+ *
>+ * The tables in the table directory must be listed in alphabetical
>+ * order.  The "cvt", "fpgm", and "prep" are optional tables. They
>+ * will only be embedded in the subset if they exist in the source
>+ * font. The pos parameter of cairo_truetype_font_add_truetype_table()
>+ * specifies the position of the table in the table directory.
>+ */
>+static void
>+cairo_truetype_font_create_truetype_table_list (cairo_truetype_font_t *font)
>+{
>+    cairo_bool_t has_cvt = FALSE;
>+    cairo_bool_t has_fpgm = FALSE;
>+    cairo_bool_t has_prep = FALSE;
>+    unsigned long size;
>+    int pos;
>+
>+    size = 0;
>+    if (font->backend->load_truetype_table (font->scaled_font_subset->scaled_font,
>+                                      TT_TAG_cvt, 0, NULL,
>+                                      &size) == CAIRO_STATUS_SUCCESS)
>+        has_cvt = TRUE;
>+
>+    size = 0;
>+    if (font->backend->load_truetype_table (font->scaled_font_subset->scaled_font,
>+                                      TT_TAG_fpgm, 0, NULL,
>+                                      &size) == CAIRO_STATUS_SUCCESS)
>+        has_fpgm = TRUE;
>+
>+    size = 0;
>+    if (font->backend->load_truetype_table (font->scaled_font_subset->scaled_font,
>+                                      TT_TAG_prep, 0, NULL,
>+                                      &size) == CAIRO_STATUS_SUCCESS)
>+        has_prep = TRUE;
>+
>+    font->num_tables = 0;
>+    pos = 1;
>+    if (has_cvt)
>+        pos++;
>+    if (has_fpgm)
>+        pos++;
>+    cairo_truetype_font_add_truetype_table (font, TT_TAG_glyf, cairo_truetype_font_write_glyf_table, pos);
>+
>+    pos = 0;
>+    cairo_truetype_font_add_truetype_table (font, TT_TAG_cmap, cairo_truetype_font_write_cmap_table, pos++);
>+    if (has_cvt)
>+        cairo_truetype_font_add_truetype_table (font, TT_TAG_cvt, cairo_truetype_font_write_generic_table, pos++);
>+    if (has_fpgm)
>+        cairo_truetype_font_add_truetype_table (font, TT_TAG_fpgm, cairo_truetype_font_write_generic_table, pos++);
>+    pos++;
>+    cairo_truetype_font_add_truetype_table (font, TT_TAG_head, cairo_truetype_font_write_head_table, pos++);
>+    cairo_truetype_font_add_truetype_table (font, TT_TAG_hhea, cairo_truetype_font_write_hhea_table, pos++);
>+    cairo_truetype_font_add_truetype_table (font, TT_TAG_hmtx, cairo_truetype_font_write_hmtx_table, pos++);
>+    cairo_truetype_font_add_truetype_table (font, TT_TAG_loca, cairo_truetype_font_write_loca_table, pos++);
>+    cairo_truetype_font_add_truetype_table (font, TT_TAG_maxp, cairo_truetype_font_write_maxp_table, pos++);
>+    if (has_prep)
>+        cairo_truetype_font_add_truetype_table (font, TT_TAG_prep, cairo_truetype_font_write_generic_table, pos);
>+}
>+
> cairo_status_t
> _cairo_truetype_subset_init (cairo_truetype_subset_t    *truetype_subset,
> 			     cairo_scaled_font_subset_t	*font_subset)
>@@ -901,8 +967,9 @@ _cairo_truetype_subset_init (cairo_truet
> 	cairo_truetype_font_use_glyph (font, parent_glyph);
>     }
> 
>+    cairo_truetype_font_create_truetype_table_list (font);
>     status = cairo_truetype_font_generate (font, &data, &length,
>-					 &string_offsets, &num_strings);
>+                                           &string_offsets, &num_strings);
>     if (status)
> 	goto fail1;
> 
>-- 
>1.4.3.4
>

Actions: View | Splinter Review

Attachments on bug 10849: 9860 | 10487 | 10581 | 10631 | 11817

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.