upiwin/src/fbprimitive.c

#include "wintype.h"
#include "fbinit.h"

inline static PUINT16 loc_from_coords(INT32 x, INT32 y)
{
  return Fb_Ptr + (y * Fb_Info->width) + x;
}

UINT16 Fb_setpixel(INT32 x, INT32 y, UINT16 color, BOOL xor)
{
  UINT16 rc;
  PUINT16 loc = loc_from_coords(x, y);

  rc = *loc;
  if (xor)
    *loc ^= color;
  else
    *loc = color;
  return rc;
}

void Fb_line(INT32 x1, INT32 y1, INT32 x2, INT32 y2, UINT16 color, BOOL xor)
{
  INT32 tmp;
  INT32 dx = x2 - x1;
  INT32 dy = y2 - y1;

  /* uses Bresenham's line algorithm with fixed-point arithmetic */
  if (ABS(dx) < ABS(dy))
  {
    if (y1 > y2)
    {
      tmp = x1;
      x1 = x2;
      x2 = tmp;
      tmp = y1;
      y1 = y2;
      y2 = tmp;
      dx = -dx;
      dy = -dy;
    }
    x1 <<= 16;
    dx = (dx << 16) / dy;
    while (y1 <= y2)
    {
      Fb_setpixel(x1 >> 16, y1, color, xor);
      x1 += dx;
      y1++;
    }
  }
  else
  {
    if (x1 > x2)
    {
      tmp = x1;
      x1 = x2;
      x2 = tmp;
      tmp = y1;
      y1 = y2;
      y2 = tmp;
      dx = -dx;
      dy = -dy;
    }
    y1 <<= 16;
    dy = dx ? (dy << 16) / dx : 0;
    while (x1 <= x2)
    {
      Fb_setpixel(x1, y1 >> 16, color, xor);
      y1 += dy;
      x1++;
    }
  }
}

void Fb_rectangle(INT32 x1, INT32 y1, INT32 x2, INT32 y2, UINT16 color, BOOL xor)
{
  Fb_line(x1, y1, x2, y1, color, xor);
  Fb_line(x2, y1 + 1, x2, y2 - 1, color, xor);
  Fb_line(x1, y2, x2, y2, color, xor);
  Fb_line(x1, y1 + 1, x1, y2 - 1, color, xor);
}

void Fb_filled_rectangle(INT32 x1, INT32 y1, INT32 x2, INT32 y2, UINT16 color, BOOL xor)
{
  INT32 tmp;
  PUINT16 ps, p;

  if (x1 > x2)
  {
    tmp = x1;
    x1 = x2;
    x2 = tmp;
  }
  if (y1 > y2)
  {
    tmp = y1;
    y1 = y2;
    y2 = tmp;
  }

  ps = loc_from_coords(x1, y1);
  for (; y1 <= y2; y1++)
  {
    p = ps;
    for (tmp = x1; tmp <= x2; tmp++)
    {
      if (xor)
	*p++ ^= color;
      else
	*p++ = color;
    }
    ps += Fb_Info->width;
  }
}