AutoExpose.h

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#ifndef _AUTOEXPOSE_H
#define _AUTOEXPOSE_H
 
#include <stdint.h>
#include <stdbool.h>
 
extern uint8_t max_tries;
 
extern uint16_t start_pixel;
 
extern uint16_t stop_pixel;
 
extern uint16_t target;
 
extern uint16_t target_tolerance;
 
extern uint16_t max_dark;
 
extern uint16_t min_exposure;
 
extern uint16_t max_exposure;
 
inline uint16_t _MinPeak(uint16_t target, uint16_t target_tolerance)
{
    uint16_t min_peak = target-target_tolerance;
 
    /* ------------------------------ */
    /* | clamp min_peak at max_dark | */
    /* ------------------------------ */
 
    // guard against arithmetic wrap around where target - tol > target
    if ( min_peak > target) min_peak = max_dark;
    // guard against large tolerance where target - tol < max_dark
    else if ( min_peak < max_dark) min_peak = max_dark;
    return min_peak;
}
 
// ---------------------------------------------------------
// |                       stdint.h                        |
// |                defines UINT16_MAX as 65535            |
// | (both /usr/include/stdint.h and avr/include/stdint.h) |
// ---------------------------------------------------------
 
inline uint16_t _MaxPeak(uint16_t target, uint16_t target_tolerance)
{
    uint16_t max_peak = target + target_tolerance;
 
    /* --------------------------- */
    /* | clamp max_peak at 65535 | */
    /* --------------------------- */
    // guard against arithmetic wrap around where target + tol < target
    if ( max_peak < target) max_peak = UINT16_MAX;
    return max_peak;
}
 
#endif // _AUTOEXPOSE_H