void pixel_to_char_size (struct frame *f, int pixel_width, int pixel_height,
int *char_width, int *char_height);
void char_to_pixel_size (struct frame *f, int char_width, int char_height,
void pixel_to_char_size (struct frame *f, int pixel_width, int pixel_height,
int *char_width, int *char_height);
void char_to_pixel_size (struct frame *f, int char_width, int char_height,