Fix pango escaping and refactor escape_markup_text

Fixes #2674.

The cause of the issue was in get_pango_layout. When we call
pango_parse_markup, `text` is the escaped string, and the unescaped
string is then computed and written to `buf`. We were then passing the
unescaped string to pango_layout_set_markup, but this function needs the
escaped string. `buf` is not needed and has been removed.

The other part of this PR refactors escape_markup_text to remove the
dest_length argument and removes the -1 return value on error. It now
assumes that you've allocated dest to the correct length.

1 files changed, 5 insertions, 9 deletions

diff --git a/include/pango.h b/include/pango.h
index 09a535a5..6ab83c16 100644
--- a/include/pango.h
+++ b/include/pango.h
@@ -6,17 +6,13 @@
 #include <cairo/cairo.h>
 #include <pango/pangocairo.h>
 
-/* Utility function which escape characters a & < > ' ".
+/**
+ * Utility function which escape characters a & < > ' ".
  *
- * If the dest parameter is NULL, then the function returns the length of
- * of the escaped src string. The dest_length doesn't matter.
- *
- * If the dest parameter is not NULL then the fuction escapes the src string
- * an puts the escaped string in dest and returns the lenght of the escaped string.
- * The dest_length parameter is the size of dest array. If the size of dest is not
- * enough, then the function returns -1.
+ * The function returns the length of the escaped string, optionally writing the
+ * escaped string to dest if provided.
  */
-int escape_markup_text(const char *src, char *dest, int dest_length);
+size_t escape_markup_text(const char *src, char *dest);
 PangoLayout *get_pango_layout(cairo_t *cairo, const char *font,
                 const char *text, double scale, bool markup);
 void get_text_size(cairo_t *cairo, const char *font, int *width, int *height,