ref: 200239cdda62ba801df9c079a773cca999348a90
dir: /a.h/
#include <u.h>
#include <libc.h>
#include <draw.h>
#include <memdraw.h>
typedef uchar*(*filterfn)(uchar*, int, int, int);
void applyfilter(const char*, filterfn);
int clamp(int);
uchar* eallocbuf(ulong);
enum
{
Cblue,
Cgreen,
Cred,
Calpha,
};