directwrite, coretext: implement substitutions

This adds simple and sensible substitutions for generic font family
names. A helper function is introduced to reduce code duplication.

1 files changed, 31 insertions, 0 deletions

diff --git a/libass/ass_fontselect.h b/libass/ass_fontselect.h
index c989e1a..1e0959e 100644
--- a/libass/ass_fontselect.h
+++ b/libass/ass_fontselect.h
@@ -177,6 +177,37 @@ struct ass_font_stream {
     void *priv;
 };
 
+
+typedef struct ass_font_mapping ASS_FontMapping;
+
+struct ass_font_mapping {
+    const char *from;
+    const char *to;
+};
+
+/**
+ * Simple font substitution helper. This can be used to implement basic
+ * mappings from one name to another. This is useful for supporting
+ * generic font families in font providers.
+ *
+ * \param map list of mappings
+ * \param len length of list of mappings
+ * \param name font name to map from
+ * \param meta metadata struct, mapped fonts will be stored into this
+ */
+inline void ass_map_font(const ASS_FontMapping *map, int len, const char *name,
+                         ASS_FontProviderMetaData *meta)
+{
+    for (int i = 0; i < len; i++) {
+        if (strcasecmp(map[i].from, name) == 0) {
+            meta->n_fullname = 1;
+            meta->fullnames = calloc(1, sizeof(char *));
+            meta->fullnames[0] = strdup(map[i].to);
+            return;
+        }
+    }
+}
+
 ASS_FontSelector *
 ass_fontselect_init(ASS_Library *library,
                     FT_Library ftlibrary, const char *family,