6 typedef int img_output_func(FILE *f, const char *filename,
7 unsigned width, unsigned height,
8 unsigned char *pixels, unsigned char *pixel_mask,
9 struct lbx_colour *palette);
11 img_output_func img_output_pbm, img_output_ppm, img_output_pam;
12 img_output_func img_output_png;
14 _Bool img_is_masked(unsigned char *mask, unsigned width, unsigned height);