plotutils-graph-patches-lloda/libplot/g_miscmi.c

/* This file is part of the GNU plotutils package.  Copyright (C) 1995,
   1996, 1997, 1998, 1999, 2000, 2005, 2008, Free Software Foundation, Inc.

   The GNU plotutils package is free software.  You may redistribute it
   and/or modify it under the terms of the GNU General Public License as
   published by the Free Software foundation; either version 2, or (at your
   option) any later version.

   The GNU plotutils package is distributed in the hope that it will be
   useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License along
   with the GNU plotutils package; see the file COPYING.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin St., Fifth Floor,
   Boston, MA 02110-1301, USA. */

/* This file contains a function called by Bitmap Plotters (including PNM
   Plotters), and GIF Plotters, just before drawing.  It sets the
   attributes in the graphics context (of type `miGC') used by the libxmi
   scan conversion routines. */

#include "sys-defines.h"
#include "extern.h"
#include "xmi.h"		/* use libxmi scan conversion module */

/* libxmi joinstyles, indexed by internal number (miter/rd./bevel/triangular)*/
static const int mi_join_style[] =
{ MI_JOIN_MITER, MI_JOIN_ROUND, MI_JOIN_BEVEL, MI_JOIN_TRIANGULAR };

/* libxmi capstyles, indexed by internal number (butt/rd./project/triangular)*/
static const int mi_cap_style[] =
{ MI_CAP_BUTT, MI_CAP_ROUND, MI_CAP_PROJECTING, MI_CAP_TRIANGULAR };

void
_set_common_mi_attributes (plDrawState *drawstate, void * ptr)
{
  int line_style, num_dashes, offset;
  unsigned int *dashbuf;
  bool dash_array_allocated = false;
  miGCAttribute attributes[5];
  int values [5];
  unsigned int local_dashbuf[PL_MAX_DASH_ARRAY_LEN];
  miGC *pGC;

  pGC = (miGC *)ptr;		/* recover passed libxmi GC */

  /* set all miGC attributes that are not dash related */

  /* set five integer-valued miGC attributes */
  attributes[0] = MI_GC_FILL_RULE;
  values[0] = (drawstate->fill_rule_type == PL_FILL_NONZERO_WINDING ? 
	       MI_WINDING_RULE : MI_EVEN_ODD_RULE);
  attributes[1] = MI_GC_JOIN_STYLE;
  values[1] = mi_join_style[drawstate->join_type];
  attributes[2] = MI_GC_CAP_STYLE;
  values[2] = mi_cap_style[drawstate->cap_type];
  attributes[3] = MI_GC_ARC_MODE;
  values[3] = MI_ARC_CHORD;	/* libplot convention */
  attributes[4] = MI_GC_LINE_WIDTH;
  values[4] = drawstate->quantized_device_line_width;
  miSetGCAttribs (pGC, 5, attributes, values);

  /* set a double-valued miGC attribute */
  miSetGCMiterLimit (pGC, drawstate->miter_limit);

  /* now determine and set dashing-related attributes */

  if (drawstate->dash_array_in_effect)
    /* have user-specified dash array */
    {
      int i;
      
      num_dashes = drawstate->dash_array_len;
      if (num_dashes > 0)
	/* non-solid line type */
	{
	  bool odd_length;
	  double min_sing_val, max_sing_val;
	  int dash_cycle_length;

	  /* compute minimum singular value of user->device coordinate map,
	     which we use as a multiplicative factor to convert line widths
	     (cf. g_linewidth.c), dash lengths, etc. */
	  _matrix_sing_vals (drawstate->transform.m, 
			     &min_sing_val, &max_sing_val);
	  
	  line_style = MI_LINE_ON_OFF_DASH;
	  odd_length = (num_dashes & 1 ? true : false);
	  {
	    int array_len;
	    
	    array_len = (odd_length ? 2 : 1) * num_dashes;
	    if (array_len <= PL_MAX_DASH_ARRAY_LEN)
	      dashbuf = local_dashbuf; /* use dash buffer on stack */
	    else
	      {
		dashbuf = (unsigned int *)_pl_xmalloc (array_len * sizeof(unsigned int));
		dash_array_allocated = true;
	      }
	  }
	  dash_cycle_length = 0;
	  for (i = 0; i < num_dashes; i++)
	    {
	      double unrounded_dashlen;
	      int dashlen;

	      unrounded_dashlen = 
		min_sing_val * drawstate->dash_array[i];

	      dashlen = IROUND(unrounded_dashlen);
	      dashlen = IMAX(dashlen, 1);

	      dashbuf[i] = (unsigned int)dashlen;
	      dash_cycle_length += dashlen;
	      if (odd_length)
		{
		  dashbuf[num_dashes + i] = (unsigned int)dashlen;
		  dash_cycle_length += dashlen;
		}
	    }
	  if (odd_length)
	    num_dashes *= 2;

	  offset = IROUND(min_sing_val * drawstate->dash_offset);
	  if (dash_cycle_length > 0)
	    /* choose an offset in range 0..dash_cycle_length-1 */
	    {
	      while (offset < 0)
		offset += dash_cycle_length;
	      offset %= dash_cycle_length;
	    }
	}
      else
	/* zero-length dash array, i.e. solid line type */
	{
	  line_style = MI_LINE_SOLID;
	  dashbuf = NULL;
	  offset = 0;
	}
    }
  else
    /* have one of the canonical line types */
    {
      if (drawstate->line_type == PL_L_SOLID)
	{
	  line_style = MI_LINE_SOLID;
	  num_dashes = 0;
	  dashbuf = NULL;
	  offset = 0;
	}
      else
	{
	  const int *dash_array;
	  int scale, i;
	  
	  line_style = MI_LINE_ON_OFF_DASH;
	  num_dashes =
	    _pl_g_line_styles[drawstate->line_type].dash_array_len;
	  dash_array = _pl_g_line_styles[drawstate->line_type].dash_array;
	  dashbuf = local_dashbuf; /* it is large enough */
	  offset = 0;

	  /* scale by line width in terms of pixels, if nonzero */
	  scale = drawstate->quantized_device_line_width;
	  if (scale <= 0)
	    scale = 1;

	  for (i = 0; i < num_dashes; i++)
	    {
	      int dashlen;
	      
	      dashlen = scale * dash_array[i];
	      dashlen = IMAX(dashlen, 1);
	      dashbuf[i] = (unsigned int)dashlen;
	    }
	}
    }

  /* set dash-related attributes in libxmi's graphics context */
  miSetGCAttrib (pGC, MI_GC_LINE_STYLE, line_style);
  if (line_style != (int)MI_LINE_SOLID)
    miSetGCDashes (pGC, num_dashes, dashbuf, offset);

  if (dash_array_allocated)
    free (dashbuf);
}