ScaledFont.textToGlyphs

Converts UTF-8 text to an array of glyphs, optionally with cluster mapping, that can be used to render later using scaled_font. If glyphs initially points to a non-NULL value, that array is used as a glyph buffer, and num_glyphs should point to the number of glyph entries available there. If the provided glyph array is too short for the conversion, a new glyph array is allocated using cairo_glyph_allocate() and placed in glyphs. Upon return, num_glyphs always contains the number of generated glyphs. If the value glyphs points to has changed after the call, the user is responsible for freeing the allocated glyph array using cairo_glyph_free(). This may happen even if the provided array was large enough. If clusters is not NULL, num_clusters and cluster_flags should not be NULL, and cluster mapping will be computed. The semantics of how cluster array allocation works is similar to the glyph array. That is, if clusters initially points to a non-NULL value, that array is used as a cluster buffer, and num_clusters should point to the number of cluster entries available there. If the provided cluster array is too short for the conversion, a new cluster array is allocated using cairo_text_cluster_allocate() and placed in clusters. Upon return, num_clusters always contains the number of generated clusters. If the value clusters points at has changed after the call, the user is responsible for freeing the allocated cluster array using cairo_text_cluster_free(). This may happen even if the provided array was large enough. In the simplest case, glyphs and clusters can point to NULL initially Since 1.8