Bresenham algorithm

Defines
#define	BRESENHAM_INIT(dx, dy, fraction, stepx, stepy, dx2, dy2)
#define	BRESENHAM_STEP(x, y, fraction, stepx, stepy, dx2, dy2)

---

Detailed Description

Bresenham line drawing algorithm. Implemented as macros for flexibility and speed.

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Define Documentation

#define BRESENHAM_INIT	(	dx,
		dy,
		fraction,
		stepx,
		stepy,
		dx2,
		dy2		)

Value:

{                                                                 \
        (dx2) = (dx) << 1;                                            \
        (dy2) = (dy) << 1;                                            \
                                                                      \
        if ((dy) < 0)                                                 \
        {                                                             \
            (dy2) = -(dy2);                                           \
            (stepy) = -1;                                             \
        }                                                             \
        else                                                          \
        {                                                             \
            (stepy) = 1;                                              \
        }                                                             \
                                                                      \
        if ((dx) < 0)                                                 \
        {                                                             \
            (dx2) = -(dx2);                                           \
            (stepx) = -1;                                             \
        }                                                             \
        else                                                          \
        {                                                             \
            (stepx) = 1;                                              \
        }                                                             \
                                                                      \
        if ((dx2) > (dy2))                                            \
            (fraction) = (dy2) - (dx) * (stepx);                      \
        else                                                          \
            (fraction) = (dx2) - (dy) * (stepy);                      \
    }

Bresenham init. dx & dy are input only and will not be changed. All other parameters are the outputs which will be initialized

Definition at line 1563 of file define.h.

#define BRESENHAM_STEP	(	x,
		y,
		fraction,
		stepx,
		stepy,
		dx2,
		dy2		)

Value:

if ((dx2) > (dy2))                                                \
    {                                                                 \
        if ((fraction) >= 0)                                          \
        {                                                             \
            (y) += (stepy);                                           \
            (fraction) -= (dx2);                                      \
        }                                                             \
                                                                      \
        (x) += (stepx);                                               \
        (fraction) += (dy2);                                          \
    }                                                                 \
    else                                                              \
    {                                                                 \
        if ((fraction) >= 0)                                          \
        {                                                             \
            (x) += (stepx);                                           \
            (fraction) -= (dy2);                                      \
        }                                                             \
                                                                      \
        (y) += (stepy);                                               \
        (fraction) += (dx2);                                          \
    }

Bresenham line stepping macro. x, y are input-output and will be always be changed fraction is also input-output, but should be initialized with BRESENHAM_INIT. stepx, stepy, dx2 and dy2 are input only and should also be initialized by BRESENHAM_INIT

Definition at line 1601 of file define.h.