/* This is file REGION.CC */
/*
** Copyright (C) 1991 DJ Delorie, 24 Kirsten Ave, Rochester NH 03867-2954
**
** This file is distributed under the terms listed in the document
** "copying.dj", available from DJ Delorie at the address above.
** A copy of "copying.dj" should accompany this file; if not, a copy
** should be available from where this file was obtained.  This file
** may not be distributed without a verbatim copy of "copying.dj".
**
** This file is distributed WITHOUT ANY WARRANTY; without even the implied
** warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*/

/* History:251,33 */
#include <std.h>
#include <sys/registers.h>
#include "graphics.h"

static GrRegion *screen_region = 0;
extern int _GrCurMode;

static void SetModeHook()
{
  screen_region->width = GrSizeX();
  screen_region->height = GrSizeY();
  screen_region->row_scale = GrSizeX();
  screen_region->data = (unsigned char *)0xd0000000;
  screen_region->rdata = (unsigned char *)0xd0100000;
  screen_region->wdata = (unsigned char *)0xd0200000;
}

extern int _GrSetModeHook;

GrRegion *GrScreenRegion()
{
  if (_GrCurMode < GR_320_200_graphics)
    GrSetMode(GR_default_graphics);
  if (!screen_region)
    screen_region = new GrRegion();
  _GrSetModeHook = (int)SetModeHook;
  SetModeHook();
  return screen_region;
}

GrRegion::GrRegion()
{
  flags = width = height = row_scale = 0;
  rdata = wdata = data = 0;
  parent = 0;
  rel_x = rel_y = abs_x = abs_y = 0;
  color = GrWhite();
}

GrRegion::GrRegion(int w, int h)
{
  flags = 1;
  rdata = wdata = data = (unsigned char *)malloc(w*h);
  bzero(data,w*h);
  width = w;
  height = h;
  row_scale = w;
  color = GrWhite();
  parent = 0;
  rel_x = rel_y = abs_x = abs_y = 0;
}

GrRegion::~GrRegion()
{
  if (flags && data)
    free(data);
}

GrRegion *GrRegion::SubRegion(int x, int y, int w, int h)
{
  if (!data) return 0;
  GrRegion *tmp = new GrRegion();
  if (!tmp) return 0;
  if ((x < 0) || (y < 0))
    return tmp;
  if ((x >= width) || (y >= height))
    return tmp;
  if (x+w > width)
    w = width - x;
  if (y+h > height)
    h = height - y;
  tmp->parent = this;
  tmp->rel_x = x;
  tmp->rel_y = y;
  tmp->abs_x = x + rel_x;
  tmp->abs_y = y + rel_y;
  tmp->data = data + y*row_scale + x;
  tmp->rdata = rdata + y*row_scale + x;
  tmp->wdata = wdata + y*row_scale + x;
  tmp->width = w;
  tmp->height = h;
  tmp->row_scale = row_scale;
  return tmp;
}

int GrRegion::MaxX()
{
  return width-1;
}

int GrRegion::MaxY()
{
  return height-1;
}

int GrRegion::SizeX()
{
  return width;
}

int GrRegion::SizeY()
{
  return height;
}

void GrRegion::Plot(int x, int y, int c)
{
  if (!data) return;
  if (c == -1) c = color;
  if ((x < 0) || (y < 0) || (x >= width) || (y >= height))
    return;
  if (c & 0x100)
    data[x+y*row_scale] ^= c;
  else
    data[x+y*row_scale] = c;
}

void GrRegion::Line(int x1, int y1, int x2, int y2, int c)
{
  if (!data) return;
  if (c == -1) c = color;
  if (x1 == x2)
  {
    VLine(x1, y1, y2, c);
    return;
  }
  if (y1 == y2)
  {
    HLine(x1, x2, y1, c);
    return;
  }

  int dx, dy, sx, sy;
  int count;
  int brc, brmax;

  sx = sy = 1;
  dx = x2 - x1;
  dy = y2 - y1;
  if (dx < 0)
  {
    dx *= -1;
    sx *= -1;
  }
  if (dy < 0)
  {
    dy *= -1;
    sy *= -1;
  }
  if (dx > dy)
  {
    brmax = dx;
    brc = dx / 2;
    Plot(x1, y1, c);
    for (count = dx; count; count--)
    {
      x1 += sx;
      brc += dy;
      if (brc > brmax)
      {
        brc -= dx;
        y1 += sy;
      }
      Plot(x1, y1, c);
    }
  }
  else
  {
    brmax = dy;
    brc = dy / 2;
    Plot(x1, y1, c);
    for (count = dy; count; count--)
    {
      y1 += sy;
      brc += dx;
      if (brc > brmax)
      {
        brc -= dy;
        x1 += sx;
      }
      Plot(x1, y1, c);
    }
  }
}

void GrRegion::HLine(int x1, int x2, int y, int c)
{
  if (!data) return;
  if (c == -1) c = color;
  if ((y < 0) || (y >= height))
    return;
  if (x1 > x2)
  {
    x1 ^= x2; x2 ^= x1; x1 ^= x2;
  }
  if ((x1 >= width) || (x2 < 0))
    return;
  if (x1 < 0) x1 = 0;
  if (x2 >= width) x2 = width - 1;
  if (c & 0x100)
  {
    register int cnt=x2-x1+1;
    register unsigned char *ptr = data+x1+y*row_scale;
    while(cnt--)
      *ptr++ ^= c;
  }
  else
    memset(data + x1 + y * row_scale, c, x2 - x1 + 1);
}

void GrRegion::VLine(int x, int y1, int y2, int c)
{
  if (!data) return;
  if (c == -1) c = color;
  if ((x < 0) || (x >= width))
    return;
  if (y1 > y2)
  {
    y1 ^= y2; y2 ^= y1; y1 ^= y2;
  }
  if ((y1 >= height) || (y2 < 0))
    return;
  if (y1 < 0) y1 = 0;
  if (y2 >= height) y2 = height-1;
  register unsigned char *ptr = data + y1 * row_scale + x;
  register int yc=y2-y1+1;
  register int rs = row_scale;
  if (c & 0x100)
  {
    for (; yc; yc--, ptr+=rs)
      *ptr ^= c;
  }
  else
  {
    for (; yc; yc--, ptr+=rs)
      *ptr = c;
  }
}

void GrRegion::Rectangle(int x1, int y1, int x2, int y2, int c)
{
  if (!data) return;
  if (c == -1) c = color;
  if (x1 > x2)
  {
    x1 ^= x2; x2 ^= x1; x1 ^= x2;
  }
  if (y1 > y2)
  {
    y1 ^= y2; y2 ^= y1; y1 ^= y2;
  }
  if ((x1 == x2) || (y1 == y2))
  {
    Line(x1, y1, x2, y2, c);
    return;
  }
  Line(x1, y1, x2, y1, c);	// top
  Line(x1, y1+1, x1, y2, c);	// left
  Line(x2, y1+1, x2, y2, c);	// right
  Line(x1+1, y2, x2-1, y2, c);	// botton
}

void GrRegion::Box(int x, int y, int w, int h, int c)
{
  if (!data) return;
  if (c == -1) c = color;
  if (x < 0)
  {
    w += x;
    x = 0;
  }
  if (y < 0)
  {
    h += y;
    y = 0;
  }
  if (x > width)
    return;
  if (y > height)
    return;
  if (w > width)
    w = width;
  if (h > height)
    h = height;
  if ((w <= 0) || (h <= 0))
    return;
  if (c & 0x100)
  {
    while (h--)
      HLine(x, x+w-1, y++, c);
  }
  else
  {
    while (h--)
      memset(data+x+(y++)*row_scale, c, w);
  }
}

static unsigned char *fontptr=0;

extern "C" void int10(REGISTERS *);

void GrRegion::Text(int x, int y, char *text, int fgc, int bgc)
{
  if (!data) return;
  if (fgc == -1) fgc = color;
  if (!fontptr)
  {
    REGISTERS r;
    r.ax = 0x1130;
#define CHARHEIGHT 16 /* must correspond to value below */
    r.bx = 0x0600;
    int10(&r);
    fontptr = (unsigned char *)r.bp;
  }
  int r, c, bits;
  unsigned char *fp;
  while (*text)
  {
    fp = fontptr + CHARHEIGHT * *text;
    for (r=0; r<CHARHEIGHT; r++)
    {
      bits = *fp++;
      for (c=0; c<8; c++)
        if (bits & (0x80>>c))
          Plot(x+c, y+r, fgc);
        else if (bgc != -1)
          Plot(x+c, y+r, bgc);
    }
    text++;
    x += 8;
  }
}

int GrRegion::Point(int x, int y)
{
  if (!data) return 0;
  if ((x < 0) || (y < 0) || (x >= width) || (y >= height))
    return 0;
  return data[x+y*row_scale];
}