htmltable.c

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/*************************************************************************
 * Copyright (c) 2011 AT&T Intellectual Property
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/org/documents/epl-2.0/EPL-2.0.html
 *
 * Contributors: Details at https://graphviz.org
 *************************************************************************/
 
// Implementation of HTML-like tables.
//
// The (now purged) CodeGen graphics model, especially with integral
// coordinates, is not adequate to handle this as we would like. In particular,
// it is difficult to handle notions of adjacency and correct rounding to
// pixels. For example, if 2 adjacent boxes bb1.UR.x == bb2.LL.x, the rectangles
// may be drawn overlapping. However, if we use bb1.UR.x+1 == bb2.LL.x
// there may or may not be a gap between them, even in the same device
// depending on their positions. When CELLSPACING > 1, this isn't as much
// of a problem.
//
// We allow negative spacing as a hack to allow overlapping cell boundaries.
// For the reasons discussed above, this is difficult to get correct.
// This is an important enough case we should extend the table model to
// support it correctly. This could be done by allowing a table attribute,
// e.g., CELLGRID=n, which sets CELLBORDER=0 and has the border drawing
// handled correctly by the table.
 
#include "config.h"
 
#include <assert.h>
#include <cdt/cdt.h>
#include <common/htmltable.h>
#include <common/pointset.h>
#include <common/render.h>
#include <float.h>
#include <inttypes.h>
#include <limits.h>
#include <math.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <util/agxbuf.h>
#include <util/alloc.h>
#include <util/bitarray.h>
#include <util/exit.h>
#include <util/gv_math.h>
#include <util/prisize_t.h>
#include <util/strcasecmp.h>
#include <util/streq.h>
#include <util/unreachable.h>
 
#define DEFAULT_BORDER 1
#define DEFAULT_CELLPADDING 2
#define DEFAULT_CELLSPACING 2
 
typedef struct {
  char *url;
  char *tooltip;
  char *target;
  char *id;
  bool explicit_tooltip;
  point LL;
  point UR;
} htmlmap_data_t;
 
#ifdef DEBUG
static void printCell(htmlcell_t *cp, int ind);
#endif
 
/* Replace current font attributes in env with ones from fp,
 * storing old attributes in savp. We only deal with attributes
 * set in env. The attributes are restored via popFontInfo.
 */
static void pushFontInfo(htmlenv_t *env, textfont_t *fp, textfont_t *savp) {
  if (env->finfo.name) {
    if (fp->name) {
      savp->name = env->finfo.name;
      env->finfo.name = fp->name;
    } else
      savp->name = NULL;
  }
  if (env->finfo.color) {
    if (fp->color) {
      savp->color = env->finfo.color;
      env->finfo.color = fp->color;
    } else
      savp->color = NULL;
  }
  if (env->finfo.size >= 0) {
    if (fp->size >= 0) {
      savp->size = env->finfo.size;
      env->finfo.size = fp->size;
    } else
      savp->size = -1.0;
  }
}
 
/* Restore saved font attributes.
 * Copy only set values.
 */
static void popFontInfo(htmlenv_t *env, textfont_t *savp) {
  if (savp->name)
    env->finfo.name = savp->name;
  if (savp->color)
    env->finfo.color = savp->color;
  if (savp->size >= 0.0)
    env->finfo.size = savp->size;
}
 
static void emit_htextspans(GVJ_t *job, size_t nspans, htextspan_t *spans,
                            pointf p, double halfwidth_x, textfont_t finfo,
                            boxf b, int simple) {
  double center_x, left_x, right_x;
  textspan_t tl;
  textfont_t tf;
  pointf p_ = {0.0, 0.0};
  textspan_t *ti;
 
  center_x = p.x;
  left_x = center_x - halfwidth_x;
  right_x = center_x + halfwidth_x;
 
  /* Initial p is in center of text block; set initial baseline
   * to top of text block.
   */
  p_.y = p.y + (b.UR.y - b.LL.y) / 2.0;
 
  gvrender_begin_label(job, LABEL_HTML);
  for (size_t i = 0; i < nspans; i++) {
    /* set p.x to leftmost point where the line of text begins */
    switch (spans[i].just) {
    case 'l':
      p.x = left_x;
      break;
    case 'r':
      p.x = right_x - spans[i].size;
      break;
    default:
    case 'n':
      p.x = center_x - spans[i].size / 2.0;
      break;
    }
    p_.y -= spans[i].lfsize; /* move to current base line */
 
    ti = spans[i].items;
    for (size_t j = 0; j < spans[i].nitems; j++) {
      if (ti->font && ti->font->size > 0)
        tf.size = ti->font->size;
      else
        tf.size = finfo.size;
      if (ti->font && ti->font->name)
        tf.name = ti->font->name;
      else
        tf.name = finfo.name;
      if (ti->font && ti->font->color)
        tf.color = ti->font->color;
      else
        tf.color = finfo.color;
      if (ti->font && ti->font->flags)
        tf.flags = ti->font->flags;
      else
        tf.flags = 0;
 
      gvrender_set_pencolor(job, tf.color);
 
      tl.str = ti->str;
      tl.font = &tf;
      tl.yoffset_layout = ti->yoffset_layout;
      if (simple)
        tl.yoffset_centerline = ti->yoffset_centerline;
      else
        tl.yoffset_centerline = 1;
      tl.font->postscript_alias = ti->font->postscript_alias;
      tl.layout = ti->layout;
      tl.size.x = ti->size.x;
      tl.size.y = spans[i].lfsize;
      tl.just = 'l';
 
      p_.x = p.x;
      gvrender_textspan(job, p_, &tl);
      p.x += ti->size.x;
      ti++;
    }
  }
 
  gvrender_end_label(job);
}
 
static void emit_html_txt(GVJ_t *job, htmltxt_t *tp, htmlenv_t *env) {
  double halfwidth_x;
  pointf p;
 
  /* make sure that there is something to do */
  if (tp->nspans < 1)
    return;
 
  halfwidth_x = (tp->box.UR.x - tp->box.LL.x) / 2.0;
  p.x = env->pos.x + (tp->box.UR.x + tp->box.LL.x) / 2.0;
  p.y = env->pos.y + (tp->box.UR.y + tp->box.LL.y) / 2.0;
 
  emit_htextspans(job, tp->nspans, tp->spans, p, halfwidth_x, env->finfo,
                  tp->box, tp->simple);
}
 
static void doSide(GVJ_t *job, pointf p, double wd, double ht) {
  boxf BF;
 
  BF.LL = p;
  BF.UR.x = p.x + wd;
  BF.UR.y = p.y + ht;
  gvrender_box(job, BF, 1);
}
 
/* Convert boxf into four corner points
 * If border is > 1, inset the points by half the border.
 * It is assumed AF is pointf[4], so the data is store there
 * and AF is returned.
 */
static pointf *mkPts(pointf *AF, boxf b, int border) {
  AF[0] = b.LL;
  AF[2] = b.UR;
  if (border > 1) {
    const double delta = border / 2.0;
    AF[0].x += delta;
    AF[0].y += delta;
    AF[2].x -= delta;
    AF[2].y -= delta;
  }
  AF[1].x = AF[2].x;
  AF[1].y = AF[0].y;
  AF[3].x = AF[0].x;
  AF[3].y = AF[2].y;
 
  return AF;
}
 
/* Draw a rectangular border for the box b.
 * Handles dashed and dotted styles, rounded corners.
 * Also handles thick lines.
 * Assume dp->border > 0
 */
static void doBorder(GVJ_t *job, htmldata_t *dp, boxf b) {
  pointf AF[7];
  char *sptr[2];
  char *color = dp->pencolor ? dp->pencolor : DEFAULT_COLOR;
  unsigned short sides;
 
  gvrender_set_pencolor(job, color);
  if (dp->style.dashed || dp->style.dotted) {
    sptr[0] = sptr[1] = NULL;
    if (dp->style.dashed)
      sptr[0] = "dashed";
    else if (dp->style.dotted)
      sptr[0] = "dotted";
    gvrender_set_style(job, sptr);
  } else
    gvrender_set_style(job, job->gvc->defaultlinestyle);
  gvrender_set_penwidth(job, dp->border);
 
  if (dp->style.rounded)
    round_corners(job, mkPts(AF, b, dp->border), 4,
                  (graphviz_polygon_style_t){.rounded = true}, 0);
  else if ((sides = (dp->flags & BORDER_MASK))) {
    mkPts(AF + 1, b, dp->border); /* AF[1-4] has LL=SW,SE,UR=NE,NW */
    switch (sides) {
    case BORDER_BOTTOM:
      gvrender_polyline(job, AF + 1, 2);
      break;
    case BORDER_RIGHT:
      gvrender_polyline(job, AF + 2, 2);
      break;
    case BORDER_TOP:
      gvrender_polyline(job, AF + 3, 2);
      break;
    case BORDER_LEFT:
      AF[0] = AF[4];
      gvrender_polyline(job, AF, 2);
      break;
    case BORDER_BOTTOM | BORDER_RIGHT:
      gvrender_polyline(job, AF + 1, 3);
      break;
    case BORDER_RIGHT | BORDER_TOP:
      gvrender_polyline(job, AF + 2, 3);
      break;
    case BORDER_TOP | BORDER_LEFT:
      AF[5] = AF[1];
      gvrender_polyline(job, AF + 3, 3);
      break;
    case BORDER_LEFT | BORDER_BOTTOM:
      AF[0] = AF[4];
      gvrender_polyline(job, AF, 3);
      break;
    case BORDER_BOTTOM | BORDER_RIGHT | BORDER_TOP:
      gvrender_polyline(job, AF + 1, 4);
      break;
    case BORDER_RIGHT | BORDER_TOP | BORDER_LEFT:
      AF[5] = AF[1];
      gvrender_polyline(job, AF + 2, 4);
      break;
    case BORDER_TOP | BORDER_LEFT | BORDER_BOTTOM:
      AF[5] = AF[1];
      AF[6] = AF[2];
      gvrender_polyline(job, AF + 3, 4);
      break;
    case BORDER_LEFT | BORDER_BOTTOM | BORDER_RIGHT:
      AF[0] = AF[4];
      gvrender_polyline(job, AF, 4);
      break;
    case BORDER_TOP | BORDER_BOTTOM:
      gvrender_polyline(job, AF + 1, 2);
      gvrender_polyline(job, AF + 3, 2);
      break;
    case BORDER_LEFT | BORDER_RIGHT:
      AF[0] = AF[4];
      gvrender_polyline(job, AF, 2);
      gvrender_polyline(job, AF + 2, 2);
      break;
    default:
      break;
    }
  } else {
    if (dp->border > 1) {
      const double delta = dp->border / 2.0;
      b.LL.x += delta;
      b.LL.y += delta;
      b.UR.x -= delta;
      b.UR.y -= delta;
    }
    gvrender_box(job, b, 0);
  }
}
 
/* Set up fill values from given color; make pen transparent.
 * Return type of fill required.
 */
static int setFill(GVJ_t *job, char *color, int angle, htmlstyle_t style,
                   char *clrs[2]) {
  int filled;
  double frac;
  if (findStopColor(color, clrs, &frac)) {
    gvrender_set_fillcolor(job, clrs[0]);
    if (clrs[1])
      gvrender_set_gradient_vals(job, clrs[1], angle, frac);
    else
      gvrender_set_gradient_vals(job, DEFAULT_COLOR, angle, frac);
    if (style.radial)
      filled = RGRADIENT;
    else
      filled = GRADIENT;
  } else {
    gvrender_set_fillcolor(job, color);
    filled = FILL;
  }
  gvrender_set_pencolor(job, "transparent");
  return filled;
}
 
/* Save current map values.
 * Initialize fields in job->obj pertaining to anchors.
 * In particular, this also sets the output rectangle.
 * If there is something to do,
 * start the anchor and returns 1.
 * Otherwise, it returns 0.
 *
 * FIX: Should we provide a tooltip if none is set, as is done
 * for nodes, edges, etc. ?
 */
static int initAnchor(GVJ_t *job, htmlenv_t *env, htmldata_t *data, boxf b,
                      htmlmap_data_t *save) {
  obj_state_t *obj = job->obj;
  char *id;
  static int anchorId;
  agxbuf xb = {0};
 
  save->url = obj->url;
  save->tooltip = obj->tooltip;
  save->target = obj->target;
  save->id = obj->id;
  save->explicit_tooltip = obj->explicit_tooltip != 0;
  id = data->id;
  if (!id || !*id) { /* no external id, so use the internal one */
    if (!env->objid) {
      env->objid = gv_strdup(getObjId(job, obj->u.n, &xb));
      env->objid_set = true;
    }
    agxbprint(&xb, "%s_%d", env->objid, anchorId++);
    id = agxbuse(&xb);
  }
  const bool changed = initMapData(job, NULL, data->href, data->title,
                                   data->target, id, obj->u.g);
  agxbfree(&xb);
 
  if (changed) {
    if (obj->url || obj->explicit_tooltip) {
      emit_map_rect(job, b);
      gvrender_begin_anchor(job, obj->url, obj->tooltip, obj->target, obj->id);
    }
  }
  return changed;
}
 
#define RESET(fld)                                                             \
  if (obj->fld != save->fld) {                                                 \
    free(obj->fld);                                                            \
    obj->fld = save->fld;                                                      \
  }
 
/* Pop context pushed by initAnchor.
 * This is done by ending current anchor, restoring old values and
 * freeing new.
 *
 * NB: We don't save or restore geometric map info. This is because
 * this preservation of map context is only necessary for SVG-like
 * systems where graphical items are wrapped in an anchor, and we map
 * top-down. For ordinary map anchors, this is all done bottom-up, so
 * the geometric map info at the higher level hasn't been emitted yet.
 */
static void endAnchor(GVJ_t *job, htmlmap_data_t *save) {
  obj_state_t *obj = job->obj;
 
  if (obj->url || obj->explicit_tooltip)
    gvrender_end_anchor(job);
  RESET(url);
  RESET(tooltip);
  RESET(target);
  RESET(id);
  obj->explicit_tooltip = save->explicit_tooltip;
}
 
static void emit_html_cell(GVJ_t *job, htmlcell_t *cp, htmlenv_t *env);
 
/* place vertical and horizontal lines between adjacent cells and
 * extend the lines to intersect the rounded table boundary
 */
static void emit_html_rules(GVJ_t *job, htmlcell_t *cp, htmlenv_t *env,
                            char *color, htmlcell_t *nextc) {
  pointf rule_pt;
  double rule_length;
  double base;
  pointf pos = env->pos;
 
  if (!color)
    color = DEFAULT_COLOR;
  gvrender_set_fillcolor(job, color);
  gvrender_set_pencolor(job, color);
 
  boxf pts = cp->data.box;
  pts.LL.x += pos.x;
  pts.UR.x += pos.x;
  pts.LL.y += pos.y;
  pts.UR.y += pos.y;
 
  // Determine vertical line coordinate and length
  if (cp->vruled && cp->col + cp->colspan < cp->parent->column_count) {
    if (cp->row == 0) { // first row
      // extend to center of table border and add half cell spacing
      base = cp->parent->data.border + cp->parent->data.space / 2;
      rule_pt.y = pts.LL.y - cp->parent->data.space / 2;
    } else if (cp->row + cp->rowspan == cp->parent->row_count) { // bottom row
      // extend to center of table border and add half cell spacing
      base = cp->parent->data.border + cp->parent->data.space / 2;
      rule_pt.y = pts.LL.y - cp->parent->data.space / 2 - base;
    } else {
      base = 0;
      rule_pt.y = pts.LL.y - cp->parent->data.space / 2;
    }
    rule_pt.x = pts.UR.x + cp->parent->data.space / 2;
    rule_length = base + pts.UR.y - pts.LL.y + cp->parent->data.space;
    doSide(job, rule_pt, 0, rule_length);
  }
  // Determine the horizontal coordinate and length
  if (cp->hruled && cp->row + cp->rowspan < cp->parent->row_count) {
    if (cp->col == 0) { // first column
      // extend to center of table border and add half cell spacing
      base = cp->parent->data.border + cp->parent->data.space / 2;
      rule_pt.x = pts.LL.x - base - cp->parent->data.space / 2;
      if (cp->col + cp->colspan == cp->parent->column_count) // also last column
        base *= 2;
      /* incomplete row of cells; extend line to end */
      else if (nextc && nextc->row != cp->row) {
        base += cp->parent->data.box.UR.x + pos.x -
                (pts.UR.x + cp->parent->data.space / 2);
      }
    } else if (cp->col + cp->colspan ==
               cp->parent->column_count) { // last column
      // extend to center of table border and add half cell spacing
      base = cp->parent->data.border + cp->parent->data.space / 2;
      rule_pt.x = pts.LL.x - cp->parent->data.space / 2;
    } else {
      base = 0;
      rule_pt.x = pts.LL.x - cp->parent->data.space / 2;
      /* incomplete row of cells; extend line to end */
      if (nextc && nextc->row != cp->row) {
        base += cp->parent->data.box.UR.x + pos.x -
                (pts.UR.x + cp->parent->data.space / 2);
      }
    }
    rule_pt.y = pts.LL.y - cp->parent->data.space / 2;
    rule_length = base + pts.UR.x - pts.LL.x + cp->parent->data.space;
    doSide(job, rule_pt, rule_length, 0);
  }
}
 
static void emit_html_tbl(GVJ_t *job, htmltbl_t *tbl, htmlenv_t *env) {
  boxf pts = tbl->data.box;
  pointf pos = env->pos;
  htmlcell_t *cp;
  static textfont_t savef;
  htmlmap_data_t saved;
  int anchor; /* if true, we need to undo anchor settings. */
  const bool doAnchor = tbl->data.href || tbl->data.target || tbl->data.title;
  pointf AF[4];
 
  if (tbl->font)
    pushFontInfo(env, tbl->font, &savef);
 
  pts.LL.x += pos.x;
  pts.UR.x += pos.x;
  pts.LL.y += pos.y;
  pts.UR.y += pos.y;
 
  if (doAnchor && !(job->flags & EMIT_CLUSTERS_LAST))
    anchor = initAnchor(job, env, &tbl->data, pts, &saved);
  else
    anchor = 0;
 
  if (!tbl->data.style.invisible) {
 
    /* Fill first */
    if (tbl->data.bgcolor) {
      char *clrs[2] = {0};
      int filled = setFill(job, tbl->data.bgcolor, tbl->data.gradientangle,
                           tbl->data.style, clrs);
      if (tbl->data.style.rounded) {
        round_corners(job, mkPts(AF, pts, tbl->data.border), 4,
                      (graphviz_polygon_style_t){.rounded = true}, filled);
      } else
        gvrender_box(job, pts, filled);
      free(clrs[0]);
      free(clrs[1]);
    }
 
    /* Draw table rules and border.
     * Draw before emitting cell contents so text is always painted above
     * table-level shapes in output formats that use source order for z-order.
     * At present, we set the penwidth to 1 for rules until we provide the
     * calculations to take into account wider rules.
     */
    gvrender_set_penwidth(job, 1.0);
    for (htmlcell_t **cells = tbl->cells; (cp = *cells++);) {
      if (cp->hruled || cp->vruled)
        emit_html_rules(job, cp, env, tbl->data.pencolor, *cells);
    }
 
    if (tbl->data.border)
      doBorder(job, &tbl->data, pts);
 
    for (htmlcell_t **cells = tbl->cells; *cells; ++cells) {
      emit_html_cell(job, *cells, env);
    }
  }
 
  if (anchor)
    endAnchor(job, &saved);
 
  if (doAnchor && (job->flags & EMIT_CLUSTERS_LAST)) {
    if (initAnchor(job, env, &tbl->data, pts, &saved))
      endAnchor(job, &saved);
  }
 
  if (tbl->font)
    popFontInfo(env, &savef);
}
 
/* The image will be centered in the given box.
 * Scaling is determined by either the image's scale attribute,
 * or the imagescale attribute of the graph object being drawn.
 */
static void emit_html_img(GVJ_t *job, htmlimg_t *cp, htmlenv_t *env) {
  pointf A[4];
  boxf bb = cp->box;
  char *scale;
 
  bb.LL.x += env->pos.x;
  bb.LL.y += env->pos.y;
  bb.UR.x += env->pos.x;
  bb.UR.y += env->pos.y;
 
  A[0] = bb.UR;
  A[2] = bb.LL;
  A[1].x = A[2].x;
  A[1].y = A[0].y;
  A[3].x = A[0].x;
  A[3].y = A[2].y;
 
  if (cp->scale)
    scale = cp->scale;
  else
    scale = env->imgscale;
  assert(cp->src);
  assert(cp->src[0]);
  gvrender_usershape(job, cp->src, A, 4, true, scale, "mc");
}
 
static void emit_html_cell(GVJ_t *job, htmlcell_t *cp, htmlenv_t *env) {
  htmlmap_data_t saved;
  boxf pts = cp->data.box;
  pointf pos = env->pos;
  int inAnchor;
  const bool doAnchor = cp->data.href || cp->data.target || cp->data.title;
  pointf AF[4];
 
  pts.LL.x += pos.x;
  pts.UR.x += pos.x;
  pts.LL.y += pos.y;
  pts.UR.y += pos.y;
 
  if (doAnchor && !(job->flags & EMIT_CLUSTERS_LAST))
    inAnchor = initAnchor(job, env, &cp->data, pts, &saved);
  else
    inAnchor = 0;
 
  if (!cp->data.style.invisible) {
    if (cp->data.bgcolor) {
      char *clrs[2];
      int filled = setFill(job, cp->data.bgcolor, cp->data.gradientangle,
                           cp->data.style, clrs);
      if (cp->data.style.rounded) {
        round_corners(job, mkPts(AF, pts, cp->data.border), 4,
                      (graphviz_polygon_style_t){.rounded = true}, filled);
      } else
        gvrender_box(job, pts, filled);
      free(clrs[0]);
    }
 
    if (cp->data.border)
      doBorder(job, &cp->data, pts);
 
    if (cp->child.kind == HTML_TBL)
      emit_html_tbl(job, cp->child.u.tbl, env);
    else if (cp->child.kind == HTML_IMAGE)
      emit_html_img(job, cp->child.u.img, env);
    else
      emit_html_txt(job, cp->child.u.txt, env);
  }
 
  if (inAnchor)
    endAnchor(job, &saved);
 
  if (doAnchor && (job->flags & EMIT_CLUSTERS_LAST)) {
    if (initAnchor(job, env, &cp->data, pts, &saved))
      endAnchor(job, &saved);
  }
}
 
/* Push new obj on stack to be used in common by all
 * html elements with anchors.
 * This inherits the type, emit_state, and object of the
 * parent, as well as the url, explicit, target and tooltip.
 */
static void allocObj(GVJ_t *job) {
  obj_state_t *obj;
  obj_state_t *parent;
 
  obj = push_obj_state(job);
  parent = obj->parent;
  obj->type = parent->type;
  obj->emit_state = parent->emit_state;
  switch (obj->type) {
  case NODE_OBJTYPE:
    obj->u.n = parent->u.n;
    break;
  case ROOTGRAPH_OBJTYPE:
    obj->u.g = parent->u.g;
    break;
  case CLUSTER_OBJTYPE:
    obj->u.sg = parent->u.sg;
    break;
  case EDGE_OBJTYPE:
    obj->u.e = parent->u.e;
    break;
  default:
    UNREACHABLE();
  }
  obj->url = parent->url;
  obj->tooltip = parent->tooltip;
  obj->target = parent->target;
  obj->explicit_tooltip = parent->explicit_tooltip;
}
 
static void freeObj(GVJ_t *job) {
  obj_state_t *obj = job->obj;
 
  obj->url = NULL;
  obj->tooltip = NULL;
  obj->target = NULL;
  obj->id = NULL;
  pop_obj_state(job);
}
 
static double heightOfLbl(htmllabel_t *lp) {
  double sz = 0.0;
 
  switch (lp->kind) {
  case HTML_TBL:
    sz = lp->u.tbl->data.box.UR.y - lp->u.tbl->data.box.LL.y;
    break;
  case HTML_IMAGE:
    sz = lp->u.img->box.UR.y - lp->u.img->box.LL.y;
    break;
  case HTML_TEXT:
    sz = lp->u.txt->box.UR.y - lp->u.txt->box.LL.y;
    break;
  default:
    UNREACHABLE();
  }
  return sz;
}
 
void emit_html_label(GVJ_t *job, htmllabel_t *lp, textlabel_t *tp) {
  htmlenv_t env;
  pointf p;
 
  allocObj(job);
 
  p = tp->pos;
  switch (tp->valign) {
  case 't':
    p.y = tp->pos.y + (tp->space.y - heightOfLbl(lp)) / 2.0 - 1;
    break;
  case 'b':
    p.y = tp->pos.y - (tp->space.y - heightOfLbl(lp)) / 2.0 - 1;
    break;
  default:
    /* no-op */
    break;
  }
  env.pos = p;
  env.finfo.color = tp->fontcolor;
  env.finfo.name = tp->fontname;
  env.finfo.size = tp->fontsize;
  env.imgscale = agget(job->obj->u.n, "imagescale");
  env.objid = job->obj->id;
  env.objid_set = false;
  if (env.imgscale == NULL || env.imgscale[0] == '\0')
    env.imgscale = "false";
  if (lp->kind == HTML_TBL) {
    htmltbl_t *tbl = lp->u.tbl;
 
    /* set basic graphics context */
    /* Need to override line style set by node. */
    gvrender_set_style(job, job->gvc->defaultlinestyle);
    if (tbl->data.pencolor)
      gvrender_set_pencolor(job, tbl->data.pencolor);
    else
      gvrender_set_pencolor(job, DEFAULT_COLOR);
    emit_html_tbl(job, tbl, &env);
  } else {
    emit_html_txt(job, lp->u.txt, &env);
  }
  if (env.objid_set)
    free(env.objid);
  freeObj(job);
}
 
void free_html_data(htmldata_t *dp) {
  free(dp->href);
  free(dp->port);
  free(dp->target);
  free(dp->id);
  free(dp->title);
  free(dp->bgcolor);
  free(dp->pencolor);
}
 
void free_html_text(htmltxt_t *t) {
  if (!t)
    return;
 
  htextspan_t *const tl = t->spans;
  for (size_t i = 0; i < t->nspans; i++) {
    textspan_t *const ti = tl[i].items;
    for (size_t j = 0; j < tl[i].nitems; j++) {
      free(ti[j].str);
      if (ti[j].layout && ti[j].free_layout)
        ti[j].free_layout(ti[j].layout);
    }
    free(ti);
  }
  free(tl);
  free(t);
}
 
static void free_html_img(htmlimg_t *ip) {
  free(ip->src);
  free(ip);
}
 
static void free_html_cell(htmlcell_t *cp) {
  free_html_label(&cp->child, 0);
  free_html_data(&cp->data);
  free(cp);
}
 
/* If tbl->row_count is `SIZE_MAX`, table is in initial state from
 * HTML parse, with data stored in `tbl->prev` and `tbl->rows`. Once run through
 * processTbl, data is stored in `tbl->parent` and `tbl->cells`, and
 * tbl->row_count is < `SIZE_MAX`.
 */
static void free_html_tbl(htmltbl_t *tbl) {
  htmlcell_t **cells;
 
  if (tbl->row_count == SIZE_MAX) { // raw, parsed table
    LIST_FREE(&tbl->rows);
  } else {
    cells = tbl->cells;
 
    free(tbl->heights);
    free(tbl->widths);
    while (*cells) {
      free_html_cell(*cells);
      cells++;
    }
    free(tbl->cells);
  }
  free_html_data(&tbl->data);
  free(tbl);
}
 
void free_html_label(htmllabel_t *lp, int root) {
  if (lp->kind == HTML_TBL)
    free_html_tbl(lp->u.tbl);
  else if (lp->kind == HTML_IMAGE)
    free_html_img(lp->u.img);
  else
    free_html_text(lp->u.txt);
  if (root)
    free(lp);
}
 
static htmldata_t *portToTbl(htmltbl_t *, char *);
 
static htmldata_t *portToCell(htmlcell_t *cp, char *id) {
  htmldata_t *rv;
 
  if (cp->data.port && strcasecmp(cp->data.port, id) == 0)
    rv = &cp->data;
  else if (cp->child.kind == HTML_TBL)
    rv = portToTbl(cp->child.u.tbl, id);
  else
    rv = NULL;
 
  return rv;
}
 
/* See if tp or any of its child cells has the given port id.
 * If true, return corresponding box.
 */
static htmldata_t *portToTbl(htmltbl_t *tp, char *id) {
  htmldata_t *rv;
  htmlcell_t **cells;
  htmlcell_t *cp;
 
  if (tp->data.port && strcasecmp(tp->data.port, id) == 0)
    rv = &tp->data;
  else {
    rv = NULL;
    cells = tp->cells;
    while ((cp = *cells++)) {
      if ((rv = portToCell(cp, id)))
        break;
    }
  }
 
  return rv;
}
 
/* See if edge port corresponds to part of the html node.
 * If successful, return pointer to port's box.
 * Else return NULL.
 */
boxf *html_port(node_t *n, char *pname, unsigned char *sides) {
  assert(pname != NULL && !streq(pname, ""));
  htmldata_t *tp;
  htmllabel_t *lbl = ND_label(n)->u.html;
  boxf *rv = NULL;
 
  if (lbl->kind == HTML_TEXT)
    return NULL;
 
  tp = portToTbl(lbl->u.tbl, pname);
  if (tp) {
    rv = &tp->box;
    *sides = tp->sides;
  }
  return rv;
}
 
static int size_html_txt(GVC_t *gvc, htmltxt_t *ftxt, htmlenv_t *env) {
  double xsize = 0.0;    /* width of text block */
  double ysize = 0.0;    /* height of text block */
  double lsize;          /* height of current line */
  double mxfsize = 0.0;  /* max. font size for the current line */
  double curbline = 0.0; /* dist. of current base line from top */
  pointf sz;
  double width;
  textspan_t lp;
  textfont_t tf = {NULL, NULL, NULL, 0.0, 0, 0};
  double maxoffset, maxlayout, mxysize = 0.0;
  bool simple = true; // one item per span, same font size/face, no flags
  double prev_fsize = -1;
  char *prev_fname = NULL;
 
  for (size_t i = 0; i < ftxt->nspans; i++) {
    if (ftxt->spans[i].nitems > 1) {
      simple = false;
      break;
    }
    if (ftxt->spans[i].items[0].font) {
      if (ftxt->spans[i].items[0].font->flags) {
        simple = false;
        break;
      }
      if (ftxt->spans[i].items[0].font->size > 0)
        tf.size = ftxt->spans[i].items[0].font->size;
      else
        tf.size = env->finfo.size;
      if (ftxt->spans[i].items[0].font->name)
        tf.name = ftxt->spans[i].items[0].font->name;
      else
        tf.name = env->finfo.name;
    } else {
      tf.size = env->finfo.size;
      tf.name = env->finfo.name;
    }
    if (i == 0)
      prev_fsize = tf.size;
    else if (tf.size != prev_fsize) {
      simple = false;
      break;
    }
    if (prev_fname == NULL)
      prev_fname = tf.name;
    else if (strcmp(tf.name, prev_fname)) {
      simple = false;
      break;
    }
  }
  ftxt->simple = simple;
 
  for (size_t i = 0; i < ftxt->nspans; i++) {
    width = 0;
    mxysize = maxoffset = maxlayout = mxfsize = 0;
    for (size_t j = 0; j < ftxt->spans[i].nitems; j++) {
      lp.str = strdup_and_subst_obj(ftxt->spans[i].items[j].str, env->obj);
      if (ftxt->spans[i].items[j].font) {
        if (ftxt->spans[i].items[j].font->flags)
          tf.flags = ftxt->spans[i].items[j].font->flags;
        else if (env->finfo.flags > 0)
          tf.flags = env->finfo.flags;
        else
          tf.flags = 0;
        if (ftxt->spans[i].items[j].font->size > 0)
          tf.size = ftxt->spans[i].items[j].font->size;
        else
          tf.size = env->finfo.size;
        if (ftxt->spans[i].items[j].font->name)
          tf.name = ftxt->spans[i].items[j].font->name;
        else
          tf.name = env->finfo.name;
        if (ftxt->spans[i].items[j].font->color)
          tf.color = ftxt->spans[i].items[j].font->color;
        else
          tf.color = env->finfo.color;
      } else {
        tf.size = env->finfo.size;
        tf.name = env->finfo.name;
        tf.color = env->finfo.color;
        tf.flags = env->finfo.flags;
      }
      lp.font = dtinsert(gvc->textfont_dt, &tf);
      sz = textspan_size(gvc, &lp);
      free(ftxt->spans[i].items[j].str);
      ftxt->spans[i].items[j].str = lp.str;
      ftxt->spans[i].items[j].size.x = sz.x;
      ftxt->spans[i].items[j].yoffset_layout = lp.yoffset_layout;
      ftxt->spans[i].items[j].yoffset_centerline = lp.yoffset_centerline;
      ftxt->spans[i].items[j].font = lp.font;
      ftxt->spans[i].items[j].layout = lp.layout;
      ftxt->spans[i].items[j].free_layout = lp.free_layout;
      width += sz.x;
      mxfsize = MAX(tf.size, mxfsize);
      mxysize = MAX(sz.y, mxysize);
      maxoffset = MAX(lp.yoffset_centerline, maxoffset);
      maxlayout = MAX(lp.yoffset_layout, maxlayout);
    }
    /* lsize = mxfsize * LINESPACING; */
    ftxt->spans[i].size = width;
    /* ysize - curbline is the distance from the previous
     * baseline to the bottom of the previous line.
     * Then, in the current line, we set the baseline to
     * be 5/6 of the max. font size. Thus, lfsize gives the
     * distance from the previous baseline to the new one.
     */
    /* ftxt->spans[i].lfsize = 5*mxfsize/6 + ysize - curbline; */
    if (simple) {
      lsize = mxysize;
      if (i == 0)
        /* Place baseline using actual font metrics: centers the pango
         * logical rectangle in the cell rather than approximating with
         * raw font size.  maxlayout = baseline distance from box top
         * (yoffset_layout from the text layout engine); maxoffset =
         * yoffset_centerline (small above-baseline correction applied
         * by the renderer to convert from rendering origin to baseline). */
        ftxt->spans[i].lfsize = maxlayout + maxoffset;
      else
        ftxt->spans[i].lfsize = mxysize;
    } else {
      lsize = mxfsize;
      if (i == 0)
        ftxt->spans[i].lfsize = mxfsize - maxoffset;
      else
        ftxt->spans[i].lfsize = mxfsize + ysize - curbline - maxoffset;
    }
    curbline += ftxt->spans[i].lfsize;
    xsize = MAX(width, xsize);
    ysize += lsize;
  }
  ftxt->box.UR.x = xsize;
  if (ftxt->nspans == 1)
    ftxt->box.UR.y = mxysize;
  else
    ftxt->box.UR.y = ysize;
  return 0;
}
 
static int size_html_tbl(graph_t *g, htmltbl_t *tbl, htmlcell_t *parent,
                         htmlenv_t *env);
 
static int size_html_img(htmlimg_t *img, htmlenv_t *env) {
  box b;
  int rv;
 
  b.LL.x = b.LL.y = 0;
  b.UR = gvusershape_size(env->g, img->src);
  if (b.UR.x == -1 && b.UR.y == -1) {
    rv = 1;
    b.UR.x = b.UR.y = 0;
    agerrorf("No or improper image file=\"%s\"\n", img->src);
  } else {
    rv = 0;
    GD_has_images(env->g) = true;
  }
 
  B2BF(b, img->box);
  return rv;
}
 
static int size_html_cell(graph_t *g, htmlcell_t *cp, htmltbl_t *parent,
                          htmlenv_t *env) {
  int rv;
  pointf sz, child_sz;
  int margin;
 
  cp->parent = parent;
  if (!(cp->data.flags & PAD_SET)) {
    if (parent->data.flags & PAD_SET)
      cp->data.pad = parent->data.pad;
    else
      cp->data.pad = DEFAULT_CELLPADDING;
  }
  if (!(cp->data.flags & BORDER_SET)) {
    if (parent->cellborder >= 0)
      cp->data.border = (unsigned char)parent->cellborder;
    else if (parent->data.flags & BORDER_SET)
      cp->data.border = parent->data.border;
    else
      cp->data.border = DEFAULT_BORDER;
  }
 
  if (cp->child.kind == HTML_TBL) {
    rv = size_html_tbl(g, cp->child.u.tbl, cp, env);
    child_sz = cp->child.u.tbl->data.box.UR;
  } else if (cp->child.kind == HTML_IMAGE) {
    rv = size_html_img(cp->child.u.img, env);
    child_sz = cp->child.u.img->box.UR;
  } else {
    rv = size_html_txt(GD_gvc(g), cp->child.u.txt, env);
    child_sz = cp->child.u.txt->box.UR;
  }
 
  margin = 2 * (cp->data.pad + cp->data.border);
  sz.x = child_sz.x + margin;
  sz.y = child_sz.y + margin;
 
  if (cp->data.flags & FIXED_FLAG) {
    if (cp->data.width && cp->data.height) {
      if ((cp->data.width < sz.x || cp->data.height < sz.y) &&
          cp->child.kind != HTML_IMAGE) {
        agwarningf("cell size too small for content\n");
        rv = 1;
      }
      sz.x = sz.y = 0;
 
    } else {
      agwarningf("fixed cell size with unspecified width or height\n");
      rv = 1;
    }
  }
  cp->data.box.UR.x = MAX(sz.x, cp->data.width);
  cp->data.box.UR.y = MAX(sz.y, cp->data.height);
  return rv;
}
 
static uint16_t findCol(PointSet *ps, int row, int col, htmlcell_t *cellp) {
  int notFound = 1;
  int lastc;
  int i, j, c;
  int end = cellp->colspan - 1;
 
  while (notFound) {
    lastc = col + end;
    for (c = lastc; c >= col; c--) {
      if (isInPS(ps, c, row))
        break;
    }
    if (c >= col) /* conflict : try column after */
      col = c + 1;
    else
      notFound = 0;
  }
  for (j = col; j < col + cellp->colspan; j++) {
    for (i = row; i < row + cellp->rowspan; i++) {
      addPS(ps, j, i);
    }
  }
  assert(col >= 0 && col <= UINT16_MAX);
  return (uint16_t)col;
}
 
/* Convert parser representation of cells into final form.
 * Find column and row positions of cells.
 * Recursively size cells.
 * Return 1 if problem sizing a cell.
 */
static int processTbl(graph_t *g, htmltbl_t *tbl, htmlenv_t *env) {
  htmlcell_t **cells;
  rows_t rows = tbl->rows;
  int rv = 0;
  size_t n_rows = 0;
  size_t n_cols = 0;
  PointSet *ps = newPS();
  bitarray_t is = bitarray_new((size_t)UINT16_MAX + 1);
 
  size_t cnt = 0;
  for (uint16_t r = 0; r < LIST_SIZE(&rows); ++r) {
    row_t *rp = LIST_GET(&rows, r);
    cnt += LIST_SIZE(&rp->rp);
    if (rp->ruled) {
      bitarray_set(&is, r + 1, true);
    }
  }
 
  cells = tbl->cells = gv_calloc(cnt + 1, sizeof(htmlcell_t *));
  for (uint16_t r = 0; r < LIST_SIZE(&rows); ++r) {
    row_t *rp = LIST_GET(&rows, r);
    uint16_t c = 0;
    for (size_t i = 0; i < LIST_SIZE(&rp->rp); ++i) {
      htmlcell_t *cellp = LIST_GET(&rp->rp, i);
      *cells++ = cellp;
      rv |= size_html_cell(g, cellp, tbl, env);
      c = findCol(ps, r, c, cellp);
      cellp->row = r;
      cellp->col = c;
      c += cellp->colspan;
      n_cols = MAX(c, n_cols);
      n_rows = MAX(r + cellp->rowspan, n_rows);
      if (bitarray_get(is, r + cellp->rowspan))
        cellp->hruled = true;
    }
  }
  tbl->row_count = n_rows;
  tbl->column_count = n_cols;
  LIST_FREE(&rows);
  bitarray_reset(&is);
  freePS(ps);
  return rv;
}
 
static void set_cell_widths(htmltbl_t *table) {
 
  // `processTbl` has already done step 1, “1. Calculate the minimum content
  // width (MCW) of each cell”, and stored it in `.data.box.UR.x`.
 
  // Allocate space for minimum column widths. Note that we add an extra entry
  // to allow later code to make references like `table->widths[col + colspan]`.
  assert(table->widths == NULL && "table widths computed twice");
  table->widths = gv_calloc(table->column_count + 1, sizeof(double));
 
  // “2. For each column, determine a … minimum column width from the cells that
  // span only that column. The minimum is that required by the cell with the
  // largest minimum cell width …”. Note that this loop and the following one
  // could be fused, but this would make the implementation harder to relate
  // back to the specification.
  for (htmlcell_t **i = table->cells; *i != NULL; ++i) {
    const htmlcell_t cell = **i;
    if (cell.colspan > 1) {
      continue;
    }
    assert(cell.col < table->column_count && "out of range cell");
    table->widths[cell.col] = fmax(table->widths[cell.col], cell.data.box.UR.x);
  }
 
  // “3. For each cell that spans more than one column, increase the minimum
  // widths of the columns it spans so that together, they are at least as wide
  // as the cell. … If possible, widen all spanned columns by approximately the
  // same amount.”
  for (htmlcell_t **i = table->cells; *i != NULL; ++i) {
    const htmlcell_t cell = **i;
    if (cell.colspan == 1) {
      continue;
    }
 
    // what is the current width of this cell’s column(s)’ span?
    double span_width = 0;
    assert(cell.col + cell.colspan <= table->column_count &&
           "cell spans wider than containing table");
    for (size_t j = 0; j < cell.colspan; ++j) {
      span_width += table->widths[cell.col + j];
    }
 
    // if it is wider than its span (including cell spacing), widen the span
    const double spacing = (cell.colspan - 1) * table->data.space;
    if (span_width + spacing < cell.data.box.UR.x) {
      const double widen_by =
          (cell.data.box.UR.x - spacing - span_width) / cell.colspan;
      for (size_t j = 0; j < cell.colspan; ++j) {
        table->widths[cell.col + j] += widen_by;
      }
    }
  }
 
  // take the minimum width for each column and apply it to its contained cells
  for (htmlcell_t **i = table->cells; *i != NULL; ++i) {
    htmlcell_t *cell = *i;
 
    // what is the current width of this cell’s column(s)’ span?
    double min_width = 0;
    assert(cell->col + cell->colspan <= table->column_count &&
           "cell spans wider than containing table");
    for (size_t j = 0; j < cell->colspan; ++j) {
      min_width += table->widths[cell->col + j];
    }
 
    // widen the cell if necessary
    const double spacing = (cell->colspan - 1) * table->data.space;
    cell->data.box.UR.x = fmax(cell->data.box.UR.x, min_width + spacing);
  }
}
 
static void set_cell_heights(htmltbl_t *table) {
 
  assert(table->heights == NULL && "table heights computed twice");
  table->heights = gv_calloc(table->row_count + 1, sizeof(double));
 
  for (htmlcell_t **i = table->cells; *i != NULL; ++i) {
    const htmlcell_t cell = **i;
    if (cell.rowspan > 1) {
      continue;
    }
    assert(cell.row < table->row_count && "out of range cell");
    table->heights[cell.row] =
        fmax(table->heights[cell.row], cell.data.box.UR.y);
  }
 
  for (htmlcell_t **i = table->cells; *i != NULL; ++i) {
    const htmlcell_t cell = **i;
    if (cell.rowspan == 1) {
      continue;
    }
 
    double span_height = 0;
    assert(cell.row + cell.rowspan <= table->row_count &&
           "cell spans higher than containing table");
    for (size_t j = 0; j < cell.rowspan; ++j) {
      span_height += table->heights[cell.row + j];
    }
 
    const double spacing = (cell.rowspan - 1) * table->data.space;
    if (span_height + spacing < cell.data.box.UR.y) {
      const double heighten_by =
          (cell.data.box.UR.y - spacing - span_height) / cell.rowspan;
      for (size_t j = 0; j < cell.rowspan; ++j) {
        table->heights[cell.row + j] += heighten_by;
      }
    }
  }
 
  for (htmlcell_t **i = table->cells; *i != NULL; ++i) {
    htmlcell_t *cell = *i;
 
    double min_height = 0;
    assert(cell->row + cell->rowspan <= table->row_count &&
           "cell spans higher than containing table");
    for (size_t j = 0; j < cell->rowspan; ++j) {
      min_height += table->heights[cell->row + j];
    }
 
    const double spacing = (cell->rowspan - 1) * table->data.space;
    cell->data.box.UR.y = fmax(cell->data.box.UR.y, min_height + spacing);
  }
}
 
static void pos_html_tbl(htmltbl_t *, boxf, unsigned char);
 
/* Place image in cell
 * storing allowed space handed by parent cell.
 * How this space is used is handled in emit_html_img.
 */
static void pos_html_img(htmlimg_t *cp, boxf pos) { cp->box = pos; }
 
static void pos_html_txt(htmltxt_t *ftxt, char c) {
  for (size_t i = 0; i < ftxt->nspans; i++) {
    if (ftxt->spans[i].just == UNSET_ALIGN) /* unset */
      ftxt->spans[i].just = c;
  }
}
 
static void pos_html_cell(htmlcell_t *cp, boxf pos, unsigned char sides) {
  double delx, dely;
  pointf oldsz;
  boxf cbox;
 
  if (!cp->data.pencolor && cp->parent->data.pencolor)
    cp->data.pencolor = gv_strdup(cp->parent->data.pencolor);
 
  /* If fixed, align cell */
  if (cp->data.flags & FIXED_FLAG) {
    oldsz = cp->data.box.UR;
    delx = pos.UR.x - pos.LL.x - oldsz.x;
    if (delx > 0) {
      switch (cp->data.flags & HALIGN_MASK) {
      case HALIGN_LEFT:
        pos.UR.x = pos.LL.x + oldsz.x;
        break;
      case HALIGN_RIGHT:
        pos.UR.x += delx;
        pos.LL.x += delx;
        break;
      default:
        pos.LL.x += delx / 2;
        pos.UR.x -= delx / 2;
        break;
      }
    }
    dely = pos.UR.y - pos.LL.y - oldsz.y;
    if (dely > 0) {
      switch (cp->data.flags & VALIGN_MASK) {
      case VALIGN_BOTTOM:
        pos.UR.y = pos.LL.y + oldsz.y;
        break;
      case VALIGN_TOP:
        pos.UR.y += dely;
        pos.LL.y += dely;
        break;
      default:
        pos.LL.y += dely / 2;
        pos.UR.y -= dely / 2;
        break;
      }
    }
  }
  cp->data.box = pos;
  cp->data.sides = sides;
 
  /* set up child's position */
  cbox.LL.x = pos.LL.x + cp->data.border + cp->data.pad;
  cbox.LL.y = pos.LL.y + cp->data.border + cp->data.pad;
  cbox.UR.x = pos.UR.x - cp->data.border - cp->data.pad;
  cbox.UR.y = pos.UR.y - cp->data.border - cp->data.pad;
 
  if (cp->child.kind == HTML_TBL) {
    pos_html_tbl(cp->child.u.tbl, cbox, sides);
  } else if (cp->child.kind == HTML_IMAGE) {
    /* Note that alignment trumps scaling */
    oldsz = cp->child.u.img->box.UR;
    delx = cbox.UR.x - cbox.LL.x - oldsz.x;
    if (delx > 0) {
      switch (cp->data.flags & HALIGN_MASK) {
      case HALIGN_LEFT:
        cbox.UR.x -= delx;
        break;
      case HALIGN_RIGHT:
        cbox.LL.x += delx;
        break;
      default:
        break;
      }
    }
 
    dely = cbox.UR.y - cbox.LL.y - oldsz.y;
    if (dely > 0) {
      switch (cp->data.flags & VALIGN_MASK) {
      case VALIGN_BOTTOM:
        cbox.UR.y -= dely;
        break;
      case VALIGN_TOP:
        cbox.LL.y += dely;
        break;
      default:
        break;
      }
    }
    pos_html_img(cp->child.u.img, cbox);
  } else {
    char dfltalign;
    int af;
 
    oldsz = cp->child.u.txt->box.UR;
    delx = cbox.UR.x - cbox.LL.x - oldsz.x;
    /* If the cell is larger than the text block and alignment is
     * done at textblock level, the text box is shrunk accordingly.
     */
    if (delx > 0 && (af = (cp->data.flags & HALIGN_MASK)) != HALIGN_TEXT) {
      switch (af) {
      case HALIGN_LEFT:
        cbox.UR.x -= delx;
        break;
      case HALIGN_RIGHT:
        cbox.LL.x += delx;
        break;
      default:
        cbox.LL.x += delx / 2;
        cbox.UR.x -= delx / 2;
        break;
      }
    }
 
    dely = cbox.UR.y - cbox.LL.y - oldsz.y;
    if (dely > 0) {
      switch (cp->data.flags & VALIGN_MASK) {
      case VALIGN_BOTTOM:
        cbox.UR.y -= dely;
        break;
      case VALIGN_TOP:
        cbox.LL.y += dely;
        break;
      default:
        cbox.LL.y += dely / 2;
        cbox.UR.y -= dely / 2;
        break;
      }
    }
    cp->child.u.txt->box = cbox;
 
    /* Set default text alignment
     */
    switch (cp->data.flags & BALIGN_MASK) {
    case BALIGN_LEFT:
      dfltalign = 'l';
      break;
    case BALIGN_RIGHT:
      dfltalign = 'r';
      break;
    default:
      dfltalign = 'n';
      break;
    }
    pos_html_txt(cp->child.u.txt, dfltalign);
  }
}
 
/* Position table given its box, then calculate
 * the position of each cell. In addition, set the sides
 * attribute indicating which external sides of the node
 * are accessible to the table.
 */
static void pos_html_tbl(htmltbl_t *tbl, boxf pos, unsigned char sides) {
  int plus;
  htmlcell_t **cells = tbl->cells;
  htmlcell_t *cp;
  boxf cbox;
 
  if (tbl->parent && tbl->parent->data.pencolor && !tbl->data.pencolor)
    tbl->data.pencolor = gv_strdup(tbl->parent->data.pencolor);
 
  double oldsz = tbl->data.box.UR.x;
  double delx = fmax(pos.UR.x - pos.LL.x - oldsz, 0);
  oldsz = tbl->data.box.UR.y;
  double dely = fmax(pos.UR.y - pos.LL.y - oldsz, 0);
 
  /* If fixed, align box */
  if (tbl->data.flags & FIXED_FLAG) {
    if (delx > 0) {
      switch (tbl->data.flags & HALIGN_MASK) {
      case HALIGN_LEFT:
        pos.UR.x = pos.LL.x + oldsz;
        break;
      case HALIGN_RIGHT:
        pos.UR.x += delx;
        pos.LL.x += delx;
        break;
      default:
        pos.LL.x += delx / 2;
        pos.UR.x -= delx / 2;
        break;
      }
      delx = 0;
    }
    if (dely > 0) {
      switch (tbl->data.flags & VALIGN_MASK) {
      case VALIGN_BOTTOM:
        pos.UR.y = pos.LL.y + oldsz;
        break;
      case VALIGN_TOP:
        pos.LL.y += dely;
        pos.UR.y = pos.LL.y + oldsz;
        break;
      default:
        pos.LL.y += dely / 2;
        pos.UR.y -= dely / 2;
        break;
      }
      dely = 0;
    }
  }
 
  /* change sizes to start positions and distribute extra space */
  double x = pos.LL.x + tbl->data.border + tbl->data.space;
  assert(tbl->column_count <= DBL_MAX);
  double extra = delx / (double)tbl->column_count;
  plus = ROUND(delx - extra * (double)tbl->column_count);
  for (size_t i = 0; i <= tbl->column_count; i++) {
    delx = tbl->widths[i] + extra + ((i <= INT_MAX && (int)i < plus) ? 1 : 0);
    tbl->widths[i] = x;
    x += delx + tbl->data.space;
  }
  double y = pos.UR.y - tbl->data.border - tbl->data.space;
  assert(tbl->row_count <= DBL_MAX);
  extra = dely / (double)tbl->row_count;
  plus = ROUND(dely - extra * (double)tbl->row_count);
  for (size_t i = 0; i <= tbl->row_count; i++) {
    dely = tbl->heights[i] + extra + ((i <= INT_MAX && (int)i < plus) ? 1 : 0);
    tbl->heights[i] = y;
    y -= dely + tbl->data.space;
  }
 
  while ((cp = *cells++)) {
    unsigned char mask = 0;
    if (sides) {
      if (cp->col == 0)
        mask |= LEFT;
      if (cp->row == 0)
        mask |= TOP;
      if (cp->col + cp->colspan == tbl->column_count)
        mask |= RIGHT;
      if (cp->row + cp->rowspan == tbl->row_count)
        mask |= BOTTOM;
    }
    cbox.LL.x = tbl->widths[cp->col];
    cbox.UR.x = tbl->widths[cp->col + cp->colspan] - tbl->data.space;
    cbox.UR.y = tbl->heights[cp->row];
    cbox.LL.y = tbl->heights[cp->row + cp->rowspan] + tbl->data.space;
    pos_html_cell(cp, cbox, sides & mask);
  }
 
  tbl->data.sides = sides;
  tbl->data.box = pos;
}
 
/* Determine the size of a table by first determining the
 * size of each cell.
 */
static int size_html_tbl(graph_t *g, htmltbl_t *tbl, htmlcell_t *parent,
                         htmlenv_t *env) {
  int rv = 0;
  static textfont_t savef;
 
  if (tbl->font)
    pushFontInfo(env, tbl->font, &savef);
  tbl->parent = parent;
  rv = processTbl(g, tbl, env);
 
  /* Set up border and spacing */
  if (!(tbl->data.flags & SPACE_SET)) {
    tbl->data.space = DEFAULT_CELLSPACING;
  }
  if (!(tbl->data.flags & BORDER_SET)) {
    tbl->data.border = DEFAULT_BORDER;
  }
 
  set_cell_widths(tbl);
  set_cell_heights(tbl);
 
  assert(tbl->column_count <= DBL_MAX);
  double wd =
      ((double)tbl->column_count + 1) * tbl->data.space + 2 * tbl->data.border;
  assert(tbl->row_count <= DBL_MAX);
  double ht =
      ((double)tbl->row_count + 1) * tbl->data.space + 2 * tbl->data.border;
  for (size_t i = 0; i < tbl->column_count; i++)
    wd += tbl->widths[i];
  for (size_t i = 0; i < tbl->row_count; i++)
    ht += tbl->heights[i];
 
  if (tbl->data.flags & FIXED_FLAG) {
    if (tbl->data.width && tbl->data.height) {
      if (tbl->data.width < wd || tbl->data.height < ht) {
        agwarningf("table size too small for content\n");
        rv = 1;
      }
      wd = 0;
      ht = 0;
    } else {
      agwarningf("fixed table size with unspecified width or height\n");
      rv = 1;
    }
  }
  tbl->data.box.UR.x = fmax(wd, tbl->data.width);
  tbl->data.box.UR.y = fmax(ht, tbl->data.height);
 
  if (tbl->font)
    popFontInfo(env, &savef);
  return rv;
}
 
static char *nameOf(void *obj, agxbuf *xb) {
  Agedge_t *ep;
  switch (agobjkind(obj)) {
  case AGRAPH:
    agxbput(xb, agnameof(obj));
    break;
  case AGNODE:
    agxbput(xb, agnameof(obj));
    break;
  case AGEDGE:
    ep = obj;
    agxbput(xb, agnameof(agtail(ep)));
    agxbput(xb, agnameof(aghead(ep)));
    if (agisdirected(agraphof(aghead(ep))))
      agxbput(xb, "->");
    else
      agxbput(xb, "--");
    break;
  }
  return agxbuse(xb);
}
 
#ifdef DEBUG
void indent(int i) {
  while (i--)
    fprintf(stderr, "  ");
}
 
void printBox(boxf b) {
  fprintf(stderr, "(%f,%f)(%f,%f)", b.LL.x, b.LL.y, b.UR.x, b.UR.y);
}
 
void printImage(htmlimg_t *ip, int ind) {
  indent(ind);
  fprintf(stderr, "img: %s\n", ip->src);
}
 
void printTxt(htmltxt_t *txt, int ind) {
  indent(ind);
  fprintf(stderr, "txt spans = %" PRISIZE_T " \n", txt->nspans);
  for (size_t i = 0; i < txt->nspans; i++) {
    indent(ind + 1);
    fprintf(stderr, "[%" PRISIZE_T "] %" PRISIZE_T " items\n", i,
            txt->spans[i].nitems);
    for (size_t j = 0; j < txt->spans[i].nitems; j++) {
      indent(ind + 2);
      fprintf(stderr, "[%" PRISIZE_T "] (%f,%f) \"%s\" ", j,
              txt->spans[i].items[j].size.x, txt->spans[i].items[j].size.y,
              txt->spans[i].items[j].str);
      if (txt->spans[i].items[j].font)
        fprintf(stderr, "font %s color %s size %f\n",
                txt->spans[i].items[j].font->name,
                txt->spans[i].items[j].font->color,
                txt->spans[i].items[j].font->size);
      else
        fprintf(stderr, "\n");
    }
  }
}
 
void printData(htmldata_t *dp) {
  unsigned char flags = dp->flags;
  char c;
 
  fprintf(stderr, "s%d(%d) ", dp->space, (flags & SPACE_SET ? 1 : 0));
  fprintf(stderr, "b%d(%d) ", dp->border, (flags & BORDER_SET ? 1 : 0));
  fprintf(stderr, "p%d(%d) ", dp->pad, (flags & PAD_SET ? 1 : 0));
  switch (flags & HALIGN_MASK) {
  case HALIGN_RIGHT:
    c = 'r';
    break;
  case HALIGN_LEFT:
    c = 'l';
    break;
  default:
    c = 'n';
    break;
  }
  fprintf(stderr, "%c", c);
  switch (flags & VALIGN_MASK) {
  case VALIGN_TOP:
    c = 't';
    break;
  case VALIGN_BOTTOM:
    c = 'b';
    break;
  default:
    c = 'c';
    break;
  }
  fprintf(stderr, "%c ", c);
  printBox(dp->box);
}
 
void printTbl(htmltbl_t *tbl, int ind) {
  htmlcell_t **cells = tbl->cells;
  indent(ind);
  fprintf(stderr, "tbl (%p) %" PRISIZE_T " %" PRISIZE_T " ", tbl,
          tbl->column_count, tbl->row_count);
  printData(&tbl->data);
  fputs("\n", stderr);
  while (*cells)
    printCell(*cells++, ind + 1);
}
 
static void printCell(htmlcell_t *cp, int ind) {
  indent(ind);
  fprintf(stderr, "cell %" PRIu16 " %" PRIu16 " %" PRIu16 " %" PRIu16 " ",
          cp->colspan, cp->colspan, cp->rowspan, cp->col, cp->row);
  printData(&cp->data);
  fputs("\n", stderr);
  switch (cp->child.kind) {
  case HTML_TBL:
    printTbl(cp->child.u.tbl, ind + 1);
    break;
  case HTML_TEXT:
    printTxt(cp->child.u.txt, ind + 1);
    break;
  case HTML_IMAGE:
    printImage(cp->child.u.img, ind + 1);
    break;
  default:
    break;
  }
}
 
void printLbl(htmllabel_t *lbl) {
  if (lbl->kind == HTML_TBL)
    printTbl(lbl->u.tbl, 0);
  else
    printTxt(lbl->u.txt, 0);
}
#endif /* DEBUG */
 
static char *getPenColor(void *obj) {
  char *str;
 
  if ((str = agget(obj, "pencolor")) != 0 && str[0])
    return str;
  else if ((str = agget(obj, "color")) != 0 && str[0])
    return str;
  else
    return NULL;
}
 
int make_html_label(void *obj, textlabel_t *lp) {
  int rv;
  double wd2, ht2;
  graph_t *g;
  htmllabel_t *lbl;
  htmlenv_t env;
  char *s;
 
  env.obj = obj;
  switch (agobjkind(obj)) {
  case AGRAPH:
    env.g = ((Agraph_t *)obj)->root;
    break;
  case AGNODE:
    env.g = agraphof(obj);
    break;
  case AGEDGE:
    env.g = agraphof(aghead(((Agedge_t *)obj)));
    break;
  }
  g = env.g->root;
 
  env.finfo.size = lp->fontsize;
  env.finfo.name = lp->fontname;
  env.finfo.color = lp->fontcolor;
  env.finfo.flags = 0;
  lbl = parseHTML(lp->text, &rv, &env);
  if (!lbl) {
    if (rv == 3) {
      // fatal error; `parseHTML` will have printed detail of it
      lp->html = false;
      return rv;
    }
    /* Parse of label failed; revert to simple text label */
    agxbuf xb = {0};
    lp->html = false;
    free(lp->text);
    lp->text = gv_strdup(nameOf(obj, &xb));
    switch (lp->charset) {
    case CHAR_LATIN1:
      s = latin1ToUTF8(lp->text);
      break;
    default: /* UTF8 */
      s = htmlEntityUTF8(lp->text, env.g);
      break;
    }
    free(lp->text);
    lp->text = s;
    make_simple_label(GD_gvc(g), lp);
    agxbfree(&xb);
    return rv;
  }
 
  if (lbl->kind == HTML_TBL) {
    if (!lbl->u.tbl->data.pencolor && getPenColor(obj))
      lbl->u.tbl->data.pencolor = gv_strdup(getPenColor(obj));
    rv |= size_html_tbl(g, lbl->u.tbl, NULL, &env);
    wd2 = lbl->u.tbl->data.box.UR.x / 2;
    ht2 = lbl->u.tbl->data.box.UR.y / 2;
    boxf b = {{-wd2, -ht2}, {wd2, ht2}};
    pos_html_tbl(lbl->u.tbl, b, BOTTOM | RIGHT | TOP | LEFT);
    lp->dimen.x = b.UR.x - b.LL.x;
    lp->dimen.y = b.UR.y - b.LL.y;
  } else {
    rv |= size_html_txt(GD_gvc(g), lbl->u.txt, &env);
    wd2 = lbl->u.txt->box.UR.x / 2;
    ht2 = lbl->u.txt->box.UR.y / 2;
    boxf b = {{-wd2, -ht2}, {wd2, ht2}};
    lbl->u.txt->box = b;
    lp->dimen.x = b.UR.x - b.LL.x;
    lp->dimen.y = b.UR.y - b.LL.y;
  }
 
  lp->u.html = lbl;
 
  /* If the label is a table, replace label text because this may
   * be used for the title and alt fields in image maps.
   */
  if (lbl->kind == HTML_TBL) {
    free(lp->text);
    lp->text = gv_strdup("<TABLE>");
  }
 
  return rv;
}