[cairo-commit] src/cairo-truetype-subset.c
Adrian Johnson
ajohnson at kemper.freedesktop.org
Sat Sep 22 19:07:16 PDT 2007
src/cairo-truetype-subset.c | 153 +++++++++++++++++++++++++++++++-------------
1 file changed, 110 insertions(+), 43 deletions(-)
New commits:
diff-tree b20e08999e2f6e7a72ee75a7c3fd865bf0368794 (from 8132b8b417c75388ce4c4671fffddaa44a5d1be0)
Author: Adrian Johnson <ajohnson at redneon.com>
Date: Sun Sep 23 11:37:02 2007 +0930
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.
diff --git a/src/cairo-truetype-subset.c b/src/cairo-truetype-subset.c
index 528f639..83f35fd 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;
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