Merge commit '7c373035e82314e6e5b4390ef32f57cf891fcfcf' as 'tkblt'

1 files changed, 1458 insertions, 0 deletions

diff --git a/tkblt/generic/tkbltGraph.C b/tkblt/generic/tkbltGraph.C
new file mode 100644
index 0000000..f1453dc
--- /dev/null
+++ b/tkblt/generic/tkbltGraph.C
@@ -0,0 +1,1458 @@
+/*
+ * Smithsonian Astrophysical Observatory, Cambridge, MA, USA
+ * This code has been modified under the terms listed below and is made
+ * available under the same terms.
+ */
+
+/*
+ *	Copyright 1991-2004 George A Howlett.
+ *
+ *	Permission is hereby granted, free of charge, to any person obtaining
+ *	a copy of this software and associated documentation files (the
+ *	"Software"), to deal in the Software without restriction, including
+ *	without limitation the rights to use, copy, modify, merge, publish,
+ *	distribute, sublicense, and/or sell copies of the Software, and to
+ *	permit persons to whom the Software is furnished to do so, subject to
+ *	the following conditions:
+ *
+ *	The above copyright notice and this permission notice shall be
+ *	included in all copies or substantial portions of the Software.
+ *
+ *	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *	EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ *	MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *	NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ *	LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ *	OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ *	WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <cfloat>
+#include <cmath>
+
+#include <tkInt.h>
+
+#include "tkbltGraph.h"
+#include "tkbltGraphOp.h"
+
+#include "tkbltGrBind.h"
+#include "tkbltGrAxis.h"
+#include "tkbltGrAxisOp.h"
+#include "tkbltGrXAxisOp.h"
+#include "tkbltGrPen.h"
+#include "tkbltGrPenBar.h"
+#include "tkbltGrPenLine.h"
+#include "tkbltGrElem.h"
+#include "tkbltGrElemBar.h"
+#include "tkbltGrElemLine.h"
+#include "tkbltGrMarker.h"
+#include "tkbltGrLegd.h"
+#include "tkbltGrHairs.h"
+#include "tkbltGrDef.h"
+#include "tkbltGrPostscript.h"
+#include "tkbltGrPSOutput.h"
+#include "tkbltInt.h"
+
+using namespace Blt;
+
+#define MARKER_ABOVE	0
+#define MARKER_UNDER	1
+
+// OptionSpecs
+
+Graph::Graph(ClientData clientData, Tcl_Interp* interp, 
+	     int objc, Tcl_Obj* const objv[])
+{
+  valid_ =1;
+  interp_ = interp;
+  tkwin_ = Tk_CreateWindowFromPath(interp_, Tk_MainWindow(interp_), 
+				  Tcl_GetString(objv[1]), NULL);
+  if (!tkwin_) {
+    valid_ =0;
+    return;
+  }
+  display_ = Tk_Display(tkwin_);
+  ((TkWindow*)tkwin_)->instanceData = this;
+
+  cmdToken_ = Tcl_CreateObjCommand(interp_, Tk_PathName(tkwin_),
+				   GraphInstCmdProc, this,
+				   GraphInstCmdDeleteProc);
+
+  flags = RESET;
+  nextMarkerId_ = 1;
+
+  inset_ =0;
+  titleX_ =0;
+  titleY_ =0;
+  titleWidth_ =0;
+  titleHeight_ =0;
+  width_ =0;
+  height_ =0;
+  left_ =0;
+  right_ =0;
+  top_ =0;
+  bottom_ =0;
+  focusPtr_ =NULL;
+  halo_ =0;
+  drawGC_ =NULL;
+  vRange_ =0;
+  hRange_ =0;
+  vOffset_ =0;
+  hOffset_ =0;
+  vScale_ =0;
+  hScale_ =0;
+  cache_ =None;
+  cacheWidth_ =0;
+  cacheHeight_ =0;
+
+  Tcl_InitHashTable(&axes_.table, TCL_STRING_KEYS);
+  Tcl_InitHashTable(&axes_.tagTable, TCL_STRING_KEYS);
+  Tcl_InitHashTable(&elements_.table, TCL_STRING_KEYS);
+  Tcl_InitHashTable(&elements_.tagTable, TCL_STRING_KEYS);
+  Tcl_InitHashTable(&markers_.table, TCL_STRING_KEYS);
+  Tcl_InitHashTable(&markers_.tagTable, TCL_STRING_KEYS);
+  Tcl_InitHashTable(&penTable_, TCL_STRING_KEYS);
+
+  axes_.displayList = new Chain();
+  elements_.displayList = new Chain();
+  markers_.displayList = new Chain();
+  bindTable_ = new BindTable(this, this);
+
+  // Keep a hold of the associated tkwin until we destroy the graph,
+  // otherwise Tk might free it while we still need it.
+  Tcl_Preserve(tkwin_);
+
+  Tk_CreateEventHandler(tkwin_, 
+			ExposureMask|StructureNotifyMask|FocusChangeMask,
+			GraphEventProc, this);
+}
+
+Graph::~Graph()
+{
+  //  GraphOptions* ops = (GraphOptions*)ops_;
+
+  destroyMarkers();
+  destroyElements();  // must come before legend and others
+
+  delete crosshairs_;
+  delete legend_;
+  delete postscript_;
+
+  destroyAxes();
+  destroyPens();
+
+  delete bindTable_;
+
+  if (drawGC_)
+    Tk_FreeGC(display_, drawGC_);
+
+  if (cache_ != None)
+    Tk_FreePixmap(display_, cache_);
+
+  Tk_FreeConfigOptions((char*)ops_, optionTable_, tkwin_);
+  Tcl_Release(tkwin_);
+  tkwin_ = NULL;
+
+  free (ops_);
+}
+
+int Graph::configure()	
+{
+  GraphOptions* ops = (GraphOptions*)ops_;
+
+  inset_ = ops->borderWidth + ops->highlightWidth;
+  if ((ops->reqHeight != Tk_ReqHeight(tkwin_)) ||
+      (ops->reqWidth != Tk_ReqWidth(tkwin_)))
+    Tk_GeometryRequest(tkwin_, ops->reqWidth, ops->reqHeight);
+
+  Tk_SetInternalBorder(tkwin_, ops->borderWidth);
+  XColor* colorPtr = Tk_3DBorderColor(ops->normalBg);
+
+  titleWidth_ =0;
+  titleHeight_ =0;
+  if (ops->title != NULL) {
+    int w, h;
+    TextStyle ts(this, &ops->titleTextStyle);
+    ts.getExtents(ops->title, &w, &h);
+    titleHeight_ = h;
+  }
+
+  // Create GCs for interior and exterior regions, and a background GC for
+  // clearing the margins with XFillRectangle
+  // Margin
+  XGCValues gcValues;
+  gcValues.foreground = ops->titleTextStyle.color->pixel;
+  gcValues.background = colorPtr->pixel;
+  unsigned long gcMask = (GCForeground | GCBackground);
+  GC newGC = Tk_GetGC(tkwin_, gcMask, &gcValues);
+  if (drawGC_ != NULL)
+    Tk_FreeGC(display_, drawGC_);
+  drawGC_ = newGC;
+
+  // If the -inverted option changed, we need to readjust the pointers
+  // to the axes and recompute the their scales.
+  adjustAxes();
+
+  // Free the pixmap if we're not buffering the display of elements anymore.
+  if (cache_ != None) {
+    Tk_FreePixmap(display_, cache_);
+    cache_ = None;
+  }
+
+  return TCL_OK;
+}
+
+void Graph::map()
+{
+  if (flags & RESET) {
+    resetAxes();
+    flags &= ~RESET;
+    flags |= LAYOUT;
+  }
+
+  if (flags & LAYOUT) {
+    layoutGraph();
+    crosshairs_->map();
+    mapAxes();
+    mapElements();
+    flags &= ~LAYOUT;
+    flags |= MAP_MARKERS | CACHE;
+  }
+
+  mapMarkers();
+}
+
+void Graph::draw()
+{
+  GraphOptions* ops = (GraphOptions*)ops_;
+
+  flags &= ~REDRAW_PENDING;
+  if ((flags & GRAPH_DELETED) || !Tk_IsMapped(tkwin_))
+    return;
+
+  // Don't bother computing the layout until the size of the window is
+  // something reasonable.
+  if ((Tk_Width(tkwin_) <= 1) || (Tk_Height(tkwin_) <= 1))
+    return;
+
+  width_ = Tk_Width(tkwin_);
+  height_ = Tk_Height(tkwin_);
+
+  map();
+
+  // Create a pixmap the size of the window for double buffering
+  Pixmap drawable = Tk_GetPixmap(display_, Tk_WindowId(tkwin_), 
+				 width_, height_, Tk_Depth(tkwin_));
+
+  if (cache_ == None || cacheWidth_ != width_ || cacheHeight_ != height_) {
+    if (cache_ != None)
+      Tk_FreePixmap(display_, cache_);
+    cache_ = Tk_GetPixmap(display_, Tk_WindowId(tkwin_), width_, height_, 
+			  Tk_Depth(tkwin_));
+    cacheWidth_ = width_;
+    cacheHeight_ = height_;
+    flags |= CACHE;
+  }
+
+  // Update cache if needed
+  if (flags & CACHE) {
+    drawMargins(cache_);
+
+    switch (legend_->position()) {
+    case Legend::TOP:
+    case Legend::BOTTOM:
+    case Legend::RIGHT:
+    case Legend::LEFT:
+      legend_->draw(cache_);
+      break;
+    default:
+      break;
+    }
+
+    // Draw the background of the plotting area with 3D border
+    Tk_Fill3DRectangle(tkwin_, cache_, ops->plotBg, 
+		       left_-ops->plotBW, 
+		       top_-ops->plotBW, 
+		       right_-left_+1+2*ops->plotBW,
+		       bottom_-top_+1+2*ops->plotBW, 
+		       ops->plotBW, ops->plotRelief);
+  
+    drawAxesGrids(cache_);
+    drawAxes(cache_);
+    drawAxesLimits(cache_);
+
+    if (!legend_->isRaised()) {
+      switch (legend_->position()) {
+      case Legend::PLOT:
+      case Legend::XY:
+	legend_->draw(cache_);
+	break;
+      default:
+	break;
+      }
+    }
+
+    drawMarkers(cache_, MARKER_UNDER);
+    drawElements(cache_);
+    drawActiveElements(cache_);
+
+    if (legend_->isRaised()) {
+      switch (legend_->position()) {
+      case Legend::PLOT:
+      case Legend::XY:
+	legend_->draw(cache_);
+	break;
+      default:
+	break;
+      }
+    }
+
+    flags &= ~CACHE;
+  }
+
+  XCopyArea(display_, cache_, drawable, drawGC_, 0, 0, Tk_Width(tkwin_),
+	    Tk_Height(tkwin_), 0, 0);
+  
+  drawMarkers(drawable, MARKER_ABOVE);
+
+  // Draw 3D border just inside of the focus highlight ring
+  if ((ops->borderWidth > 0) && (ops->relief != TK_RELIEF_FLAT))
+    Tk_Draw3DRectangle(tkwin_, drawable, ops->normalBg, 
+		       ops->highlightWidth, ops->highlightWidth, 
+		       width_ - 2*ops->highlightWidth, 
+		       height_ - 2*ops->highlightWidth, 
+		       ops->borderWidth, ops->relief);
+
+  // Draw focus highlight ring
+  if ((ops->highlightWidth > 0) && (flags & FOCUS)) {
+    GC gc = Tk_GCForColor(ops->highlightColor, drawable);
+    Tk_DrawFocusHighlight(tkwin_, gc, ops->highlightWidth, drawable);
+  }
+
+  // crosshairs
+  crosshairs_->draw(drawable);
+
+  XCopyArea(display_, drawable, Tk_WindowId(tkwin_), drawGC_, 
+	    0, 0, width_, height_, 0, 0);
+
+  Tk_FreePixmap(display_, drawable);
+}
+
+int Graph::print(const char* ident, PSOutput* psPtr)
+{
+  GraphOptions* ops = (GraphOptions*)ops_;
+  PostscriptOptions* pops = (PostscriptOptions*)postscript_->ops_;
+
+  // be sure the window is realized so that relief colors are available
+  if (flags & REDRAW_PENDING) {
+    flags |= REDRAW_PENDING;
+    DisplayGraph(this);
+  }
+
+  // We need to know how big a graph to print.  If the graph hasn't been drawn
+  // yet, the width and height will be 1.  Instead use the requested size of
+  // the widget.  The user can still override this with the -width and -height
+  // postscript options.
+  if (pops->reqWidth > 0)
+    width_ = pops->reqWidth;
+  else if (width_ < 2)
+    width_ = Tk_ReqWidth(tkwin_);
+
+  if (pops->reqHeight > 0)
+    height_ = pops->reqHeight;
+  else if (height_ < 2)
+    height_ = Tk_ReqHeight(tkwin_);
+
+  psPtr->computeBBox(width_, height_);
+  flags |= RESET;
+
+  // Turn on PostScript measurements when computing the graph's layout.
+  reconfigure();
+
+  map();
+
+  int x = left_ - ops->plotBW;
+  int y = top_ - ops->plotBW;
+
+  int w = (right_ - left_ + 1) + (2*ops->plotBW);
+  int h = (bottom_ - top_ + 1) + (2*ops->plotBW);
+
+  int result = psPtr->preamble(ident);
+  if (result != TCL_OK)
+    goto error;
+
+  psPtr->setFont(ops->titleTextStyle.font);
+  if (pops->decorations)
+    psPtr->setBackground(Tk_3DBorderColor(ops->plotBg));
+  else
+    psPtr->setClearBackground();
+
+  psPtr->fillRectangle(x, y, w, h);
+  psPtr->append("gsave\n\n");
+
+  // Start
+  printMargins(psPtr);
+
+  switch (legend_->position()) {
+  case Legend::TOP:
+  case Legend::BOTTOM:
+  case Legend::RIGHT:
+  case Legend::LEFT:
+    legend_->print(psPtr);
+    break;
+  default:
+    break;
+  }
+
+  printAxesGrids(psPtr);
+  printAxes(psPtr);
+  printAxesLimits(psPtr);
+
+  if (!legend_->isRaised()) {
+    switch (legend_->position()) {
+    case Legend::PLOT:
+    case Legend::XY:
+      legend_->print(psPtr);
+      break;
+    default:
+      break;
+    }
+  }
+
+  printMarkers(psPtr, MARKER_UNDER);
+  printElements(psPtr);
+  printActiveElements(psPtr);
+
+  if (legend_->isRaised()) {
+    switch (legend_->position()) {
+    case Legend::PLOT:
+    case Legend::XY:
+      legend_->print(psPtr);
+      break;
+    default:
+      break;
+    }
+  }
+  printMarkers(psPtr, MARKER_ABOVE);
+
+  psPtr->append("\n");
+  psPtr->append("% Unset clipping\n");
+  psPtr->append("grestore\n\n");
+  psPtr->append("showpage\n");
+  psPtr->append("%Trailer\n");
+  psPtr->append("grestore\n");
+  psPtr->append("end\n");
+  psPtr->append("%EOF\n");
+
+ error:
+  width_ = Tk_Width(tkwin_);
+  height_ = Tk_Height(tkwin_);
+  reconfigure();
+
+  // Redraw the graph in order to re-calculate the layout as soon as
+  // possible. This is in the case the crosshairs are active.
+  flags |= LAYOUT;
+  eventuallyRedraw();
+
+  return result;
+}
+
+void Graph::eventuallyRedraw() 
+{
+  if (flags & GRAPH_DELETED)
+    return;
+
+  if (!(flags & REDRAW_PENDING)) {
+    flags |= REDRAW_PENDING;
+    Tcl_DoWhenIdle(DisplayGraph, this);
+  }
+}
+
+void Graph::extents(Region2d* regionPtr)
+{
+  GraphOptions* ops = (GraphOptions*)ops_;
+
+  regionPtr->left = (double)(hOffset_ - ops->xPad);
+  regionPtr->top = (double)(vOffset_ - ops->yPad);
+  regionPtr->right = (double)(hOffset_ + hRange_ + ops->xPad);
+  regionPtr->bottom = (double)(vOffset_ + vRange_ + ops->yPad);
+}
+
+int Graph::invoke(const Ensemble* ensemble, int cmdIndex,
+		  int objc, Tcl_Obj* const objv[])
+{
+  while (cmdIndex < objc) {
+    int index;
+    if (Tcl_GetIndexFromObjStruct(interp_, objv[cmdIndex], ensemble, sizeof(ensemble[0]), "command", 0, &index) != TCL_OK)
+      return TCL_ERROR;
+
+    if (ensemble[index].proc)
+      return ensemble[index].proc(this, interp_, objc, objv);
+
+    ensemble = ensemble[index].subensemble;
+    ++cmdIndex;
+  }
+
+  Tcl_WrongNumArgs(interp_, cmdIndex, objv, "option ?arg ...?");
+  return TCL_ERROR;
+}
+
+void Graph::reconfigure()
+{
+  configure();
+  legend_->configure();
+  configureElements();
+  configureAxes();
+  configureMarkers();
+}
+
+// Margins
+
+void Graph::drawMargins(Drawable drawable)
+{
+  GraphOptions* ops = (GraphOptions*)ops_;
+  Rectangle rects[4];
+
+  // Draw the four outer rectangles which encompass the plotting
+  // surface. This clears the surrounding area and clips the plot.
+  rects[0].x = rects[0].y = rects[3].x = rects[1].x = 0;
+  rects[0].width = rects[3].width = width_;
+  rects[0].height = top_;
+  rects[3].y = bottom_;
+  rects[3].height = height_ - bottom_;
+  rects[2].y = rects[1].y = top_;
+  rects[1].width = left_;
+  rects[2].height = rects[1].height = bottom_ - top_;
+  rects[2].x = right_;
+  rects[2].width = width_ - right_;
+
+  Tk_Fill3DRectangle(tkwin_, drawable, ops->normalBg, 
+		     rects[0].x, rects[0].y, rects[0].width, rects[0].height, 
+		     0, TK_RELIEF_FLAT);
+  Tk_Fill3DRectangle(tkwin_, drawable, ops->normalBg, 
+		     rects[1].x, rects[1].y, rects[1].width, rects[1].height, 
+		     0, TK_RELIEF_FLAT);
+  Tk_Fill3DRectangle(tkwin_, drawable, ops->normalBg, 
+		     rects[2].x, rects[2].y, rects[2].width, rects[2].height, 
+		     0, TK_RELIEF_FLAT);
+  Tk_Fill3DRectangle(tkwin_, drawable, ops->normalBg, 
+		     rects[3].x, rects[3].y, rects[3].width, rects[3].height, 
+		     0, TK_RELIEF_FLAT);
+
+  // Draw 3D border around the plotting area
+  if (ops->plotBW > 0) {
+    int x = left_ - ops->plotBW;
+    int y = top_ - ops->plotBW;
+    int w = (right_ - left_) + (2*ops->plotBW);
+    int h = (bottom_ - top_) + (2*ops->plotBW);
+    Tk_Draw3DRectangle(tkwin_, drawable, ops->normalBg, 
+		       x, y, w, h, ops->plotBW, ops->plotRelief);
+  }
+  
+  if (ops->title) {
+    TextStyle ts(this, &ops->titleTextStyle);
+    ts.drawText(drawable, ops->title, titleX_, titleY_);
+  }
+}
+
+void Graph::printMargins(PSOutput* psPtr)
+{
+  GraphOptions* ops = (GraphOptions*)ops_;
+  PostscriptOptions* pops = (PostscriptOptions*)postscript_->ops_;
+  Rectangle margin[4];
+
+  margin[0].x = margin[0].y = margin[3].x = margin[1].x = 0;
+  margin[0].width = margin[3].width = width_;
+  margin[0].height = top_;
+  margin[3].y = bottom_;
+  margin[3].height = height_ - bottom_;
+  margin[2].y = margin[1].y = top_;
+  margin[1].width = left_;
+  margin[2].height = margin[1].height = bottom_ - top_;
+  margin[2].x = right_;
+  margin[2].width = width_ - right_;
+
+  // Clear the surrounding margins and clip the plotting surface
+  if (pops->decorations)
+    psPtr->setBackground(Tk_3DBorderColor(ops->normalBg));
+  else
+    psPtr->setClearBackground();
+
+  psPtr->append("% Margins\n");
+  psPtr->fillRectangles(margin, 4);
+    
+  if (pops->decorations) {
+    psPtr->append("% Interior 3D border\n");
+    if (ops->plotBW > 0) {
+      int x = left_ - ops->plotBW;
+      int y = top_ - ops->plotBW;
+      int w = (right_ - left_) + (2*ops->plotBW);
+      int h = (bottom_ - top_) + (2*ops->plotBW);
+      psPtr->print3DRectangle(ops->normalBg, (double)x, (double)y, w, h,
+			      ops->plotBW, ops->plotRelief);
+    }
+  }
+
+  if (ops->title) {
+    psPtr->append("% Graph title\n");
+    TextStyle ts(this, &ops->titleTextStyle);
+    ts.printText(psPtr, ops->title, titleX_, titleY_);
+  }
+}
+
+// Pens
+
+void Graph::destroyPens()
+{
+  Tcl_HashSearch iter;
+  for (Tcl_HashEntry *hPtr = Tcl_FirstHashEntry(&penTable_, &iter);
+       hPtr; hPtr = Tcl_NextHashEntry(&iter)) {
+    Pen* penPtr = (Pen*)Tcl_GetHashValue(hPtr);
+    delete penPtr;
+  }
+  Tcl_DeleteHashTable(&penTable_);
+}
+
+int Graph::getPen(Tcl_Obj* objPtr, Pen** penPtrPtr)
+{
+  *penPtrPtr = NULL;
+  const char *name = Tcl_GetString(objPtr);
+  if (!name || !name[0])
+    return TCL_ERROR;
+
+  Tcl_HashEntry *hPtr = Tcl_FindHashEntry(&penTable_, name);
+  if (!hPtr) {
+    Tcl_AppendResult(interp_, "can't find pen \"", name, "\" in \"", 
+		     Tk_PathName(tkwin_), "\"", NULL);
+    return TCL_ERROR;
+  }
+
+  *penPtrPtr = (Pen*)Tcl_GetHashValue(hPtr);
+
+  return TCL_OK;
+}
+
+// Elements
+
+void Graph::destroyElements()
+{
+  Tcl_HashSearch iter;
+  for (Tcl_HashEntry* hPtr=Tcl_FirstHashEntry(&elements_.table, &iter);
+       hPtr; hPtr = Tcl_NextHashEntry(&iter)) {
+    Element* elemPtr = (Element*)Tcl_GetHashValue(hPtr);
+    legend_->removeElement(elemPtr);
+    delete elemPtr;
+  }
+
+  Tcl_DeleteHashTable(&elements_.table);
+  Tcl_DeleteHashTable(&elements_.tagTable);
+  delete elements_.displayList;
+}
+
+void Graph::configureElements()
+{
+  for (ChainLink* link = Chain_FirstLink(elements_.displayList); link;
+       link = Chain_NextLink(link)) {
+    Element* elemPtr = (Element*)Chain_GetValue(link);
+    elemPtr->configure();
+  }
+}
+
+void Graph::mapElements()
+{
+  for (ChainLink* link = Chain_FirstLink(elements_.displayList); link;
+       link = Chain_NextLink(link)) {
+    Element* elemPtr = (Element*)Chain_GetValue(link);
+    elemPtr->map();
+  }
+}
+
+void Graph::drawElements(Drawable drawable)
+{
+  // Draw with respect to the stacking order
+  for (ChainLink* link=Chain_LastLink(elements_.displayList); link;
+       link = Chain_PrevLink(link)) {
+    Element* elemPtr = (Element*)Chain_GetValue(link);
+    elemPtr->draw(drawable);
+  }
+}
+
+void Graph::drawActiveElements(Drawable drawable)
+{
+  for (ChainLink* link = Chain_LastLink(elements_.displayList); link;
+       link = Chain_PrevLink(link)) {
+    Element* elemPtr = (Element*)Chain_GetValue(link);
+    elemPtr->drawActive(drawable);
+  }
+}
+
+void Graph::printElements(PSOutput* psPtr)
+{
+  for (ChainLink* link = Chain_LastLink(elements_.displayList); link;
+       link = Chain_PrevLink(link)) {
+    Element* elemPtr = (Element*)Chain_GetValue(link);
+    elemPtr->print(psPtr);
+  }
+}
+
+void Graph::printActiveElements(PSOutput* psPtr)
+{
+  for (ChainLink* link = Chain_LastLink(elements_.displayList); link;
+       link = Chain_PrevLink(link)) {
+    Element* elemPtr = (Element*)Chain_GetValue(link);
+    elemPtr->printActive(psPtr);
+  }
+}
+
+int Graph::getElement(Tcl_Obj *objPtr, Element **elemPtrPtr)
+{
+  *elemPtrPtr =NULL;
+  const char* name = Tcl_GetString(objPtr);
+  if (!name || !name[0])
+    return TCL_ERROR;
+
+  Tcl_HashEntry*hPtr = Tcl_FindHashEntry(&elements_.table, name);
+  if (!hPtr) {
+    Tcl_AppendResult(interp_, "can't find element \"", name, "\" in \"",
+		     Tk_PathName(tkwin_), "\"", NULL);
+    return TCL_ERROR;
+  }
+
+  *elemPtrPtr = (Element*)Tcl_GetHashValue(hPtr);
+  return TCL_OK;
+}
+
+ClientData Graph::elementTag(const char *tagName)
+{
+  int isNew;
+  Tcl_HashEntry* hPtr = 
+    Tcl_CreateHashEntry(&elements_.tagTable, tagName, &isNew);
+  return Tcl_GetHashKey(&elements_.tagTable, hPtr);
+}
+
+// Markers
+
+void Graph::destroyMarkers()
+{
+  Tcl_HashSearch iter;
+  for (Tcl_HashEntry* hPtr=Tcl_FirstHashEntry(&markers_.table, &iter); 
+       hPtr; hPtr=Tcl_NextHashEntry(&iter)) {
+    Marker* markerPtr = (Marker*)Tcl_GetHashValue(hPtr);
+    delete markerPtr;
+  }
+  Tcl_DeleteHashTable(&markers_.table);
+  Tcl_DeleteHashTable(&markers_.tagTable);
+  delete markers_.displayList;
+}
+
+
+void Graph::configureMarkers()
+{
+  for (ChainLink* link = Chain_FirstLink(markers_.displayList); link;
+       link = Chain_NextLink(link)) {
+    Marker* markerPtr = (Marker*)Chain_GetValue(link);
+    markerPtr->configure();
+  }
+}
+
+void Graph::mapMarkers()
+{
+  for (ChainLink* link = Chain_FirstLink(markers_.displayList); link;
+       link = Chain_NextLink(link)) {
+    Marker* markerPtr = (Marker*)Chain_GetValue(link);
+    MarkerOptions* mops = (MarkerOptions*)markerPtr->ops();
+
+    if (mops->hide)
+      continue;
+
+    if ((flags & MAP_MARKERS) || (markerPtr->flags & MAP_ITEM)) {
+      markerPtr->map();
+      markerPtr->flags &= ~MAP_ITEM;
+    }
+  }
+
+  flags &= ~MAP_MARKERS;
+}
+
+void Graph::drawMarkers(Drawable drawable, int under)
+{
+  for (ChainLink* link = Chain_LastLink(markers_.displayList); link;
+       link = Chain_PrevLink(link)) {
+    Marker* markerPtr = (Marker*)Chain_GetValue(link);
+    MarkerOptions* mops = (MarkerOptions*)markerPtr->ops();
+
+    if ((mops->drawUnder != under) || markerPtr->clipped_ || mops->hide)
+      continue;
+
+    if (isElementHidden(markerPtr))
+      continue;
+
+    markerPtr->draw(drawable);
+  }
+}
+
+void Graph::printMarkers(PSOutput* psPtr, int under)
+{
+  for (ChainLink* link = Chain_LastLink(markers_.displayList); link;
+       link = Chain_PrevLink(link)) {
+    Marker* markerPtr = (Marker*)Chain_GetValue(link);
+    MarkerOptions* mops = (MarkerOptions*)markerPtr->ops();
+    if (mops->drawUnder != under)
+      continue;
+
+    if (mops->hide)
+      continue;
+
+    if (isElementHidden(markerPtr))
+      continue;
+
+    psPtr->format("%% Marker \"%s\" is a %s.\n", 
+		  markerPtr->name_, markerPtr->className());
+    markerPtr->print(psPtr);
+  }
+}
+
+ClientData Graph::markerTag(const char* tagName)    
+{
+  int isNew;
+  Tcl_HashEntry* hPtr = Tcl_CreateHashEntry(&markers_.tagTable, tagName,&isNew);
+  return Tcl_GetHashKey(&markers_.tagTable, hPtr);
+}
+
+Marker* Graph::nearestMarker(int x, int y, int under)
+{
+  Point2d point;
+  point.x = (double)x;
+  point.y = (double)y;
+  for (ChainLink* link = Chain_FirstLink(markers_.displayList); link;
+       link = Chain_NextLink(link)) {
+    Marker* markerPtr = (Marker*)Chain_GetValue(link);
+    MarkerOptions* mops = (MarkerOptions*)markerPtr->ops();
+
+    if ((markerPtr->flags & MAP_ITEM) || mops->hide)
+      continue;
+
+    if (isElementHidden(markerPtr))
+      continue;
+
+    if (mops->drawUnder == under)
+      if (markerPtr->pointIn(&point))
+	return markerPtr;
+  }
+  return NULL;
+}
+
+int Graph::isElementHidden(Marker* markerPtr)
+{
+  MarkerOptions* mops = (MarkerOptions*)markerPtr->ops();
+
+  if (mops->elemName) {
+    Tcl_HashEntry *hPtr = Tcl_FindHashEntry(&elements_.table, mops->elemName);
+    if (hPtr) {
+      Element* elemPtr = (Element*)Tcl_GetHashValue(hPtr);
+      ElementOptions* eops = (ElementOptions*)elemPtr->ops();
+      if (!elemPtr->link || eops->hide)
+	return 1;
+    }
+  }
+  return 0;
+}
+
+// Axis
+
+int Graph::createAxes()
+{
+  for (int ii=0; ii<4; ii++) {
+    int isNew;
+    Tcl_HashEntry* hPtr = 
+      Tcl_CreateHashEntry(&axes_.table, axisNames[ii].name, &isNew);
+    Chain* chain = new Chain();
+
+    Axis* axisPtr = new Axis(this, axisNames[ii].name, ii, hPtr);
+    if (!axisPtr)
+      return TCL_ERROR;
+    AxisOptions* ops = (AxisOptions*)axisPtr->ops();
+
+    Tcl_SetHashValue(hPtr, axisPtr);
+
+    axisPtr->refCount_ = 1;
+    axisPtr->use_ =1;
+    
+    axisPtr->setClass(!(ii&1) ? CID_AXIS_X : CID_AXIS_Y);
+
+    if (Tk_InitOptions(interp_, (char*)axisPtr->ops(), 
+		       axisPtr->optionTable(), tkwin_) != TCL_OK)
+      return TCL_ERROR;
+
+    if (axisPtr->configure() != TCL_OK)
+      return TCL_ERROR;
+
+    if ((axisPtr->margin_ == MARGIN_RIGHT) || (axisPtr->margin_ == MARGIN_TOP))
+      ops->hide = 1;
+
+    axisChain_[ii] = chain;
+    axisPtr->link = chain->append(axisPtr);
+    axisPtr->chain = chain;
+  }
+  return TCL_OK;
+}
+
+int Graph::createAxis(int objc, Tcl_Obj* const objv[])
+{
+  char *string = Tcl_GetString(objv[3]);
+  if (string[0] == '-') {
+    Tcl_AppendResult(interp_, "name of axis \"", string, 
+		     "\" can't start with a '-'", NULL);
+    return TCL_ERROR;
+  }
+
+  int isNew;
+  Tcl_HashEntry* hPtr = Tcl_CreateHashEntry(&axes_.table, string, &isNew);
+  if (!isNew) {
+    Tcl_AppendResult(interp_, "axis \"", string, "\" already exists in \"",
+		     Tcl_GetString(objv[0]), "\"", NULL);
+    return TCL_ERROR;
+  }
+
+  Axis* axisPtr = new Axis(this, Tcl_GetString(objv[3]), MARGIN_NONE, hPtr);
+  if (!axisPtr)
+    return TCL_ERROR;
+
+  Tcl_SetHashValue(hPtr, axisPtr);
+
+  if ((Tk_InitOptions(interp_, (char*)axisPtr->ops(), axisPtr->optionTable(), tkwin_) != TCL_OK) || (AxisObjConfigure(axisPtr, interp_, objc-4, objv+4) != TCL_OK)) {
+    delete axisPtr;
+    return TCL_ERROR;
+  }
+
+  return TCL_OK;
+}
+
+void Graph::destroyAxes()
+{
+  Tcl_HashSearch cursor;
+  for (Tcl_HashEntry *hPtr=Tcl_FirstHashEntry(&axes_.table, &cursor);
+       hPtr; hPtr=Tcl_NextHashEntry(&cursor)) {
+    Axis *axisPtr = (Axis*)Tcl_GetHashValue(hPtr);
+    delete axisPtr;
+  }
+  Tcl_DeleteHashTable(&axes_.table);
+
+  for (int ii=0; ii<4; ii++)
+    delete axisChain_[ii];
+
+  Tcl_DeleteHashTable(&axes_.tagTable);
+  delete axes_.displayList;
+}
+
+void Graph::configureAxes()
+{
+  Tcl_HashSearch cursor;
+  for (Tcl_HashEntry *hPtr=Tcl_FirstHashEntry(&axes_.table, &cursor);
+       hPtr; hPtr = Tcl_NextHashEntry(&cursor)) {
+    Axis *axisPtr = (Axis*)Tcl_GetHashValue(hPtr);
+    axisPtr->configure();
+  }
+}
+
+void Graph::mapAxes()
+{
+  GraphOptions* ops = (GraphOptions*)ops_;
+
+  for (int ii=0; ii<4; ii++) {
+    int count =0;
+    int offset =0;
+
+    Chain* chain = ops->margins[ii].axes;
+    for (ChainLink* link=Chain_FirstLink(chain); link; 
+	 link = Chain_NextLink(link)) {
+      Axis *axisPtr = (Axis*)Chain_GetValue(link);
+      AxisOptions* aops = (AxisOptions*)axisPtr->ops();
+      if (!axisPtr->use_)
+	continue;
+
+      if (aops->reqNumMajorTicks <= 0)
+	aops->reqNumMajorTicks = 4;
+
+      if (ops->stackAxes)
+	axisPtr->mapStacked(count, ii);
+      else 
+	axisPtr->map(offset, ii);
+
+      if (aops->showGrid)
+	axisPtr->mapGridlines();
+
+      offset += axisPtr->isHorizontal() ? axisPtr->height_ : axisPtr->width_;
+      count++;
+    }
+  }
+}
+
+void Graph::drawAxes(Drawable drawable)
+{
+  GraphOptions* ops = (GraphOptions*)ops_;
+
+  for (int ii=0; ii<4; ii++) {
+    for (ChainLink* link = Chain_LastLink(ops->margins[ii].axes); link;
+	 link = Chain_PrevLink(link)) {
+      Axis *axisPtr = (Axis*)Chain_GetValue(link);
+      axisPtr->draw(drawable);
+    }
+  }
+}
+
+void Graph::drawAxesLimits(Drawable drawable)
+{
+  Tcl_HashSearch cursor;
+  for (Tcl_HashEntry* hPtr=Tcl_FirstHashEntry(&axes_.table, &cursor);
+       hPtr; hPtr = Tcl_NextHashEntry(&cursor)) {
+    Axis *axisPtr = (Axis*)Tcl_GetHashValue(hPtr);
+    axisPtr->drawLimits(drawable);
+  }
+}
+
+void Graph::drawAxesGrids(Drawable drawable)
+{
+  GraphOptions* ops = (GraphOptions*)ops_;
+
+  for (int ii=0; ii<4; ii++) {
+    for (ChainLink* link = Chain_FirstLink(ops->margins[ii].axes); link;
+	 link = Chain_NextLink(link)) {
+      Axis *axisPtr = (Axis*)Chain_GetValue(link);
+      axisPtr->drawGrids(drawable);
+    }
+  }
+}
+
+void Graph::printAxes(PSOutput* psPtr) 
+{
+  GraphOptions* ops = (GraphOptions*)ops_;
+
+  for (Margin *mp = ops->margins, *mend = mp + 4; mp < mend; mp++) {
+    for (ChainLink* link = Chain_FirstLink(mp->axes); link; 
+	 link = Chain_NextLink(link)) {
+      Axis *axisPtr = (Axis*)Chain_GetValue(link);
+      axisPtr->print(psPtr);
+    }
+  }
+}
+
+void Graph::printAxesGrids(PSOutput* psPtr) 
+{
+  GraphOptions* ops = (GraphOptions*)ops_;
+
+  for (int ii=0; ii<4; ii++) {
+    for (ChainLink* link = Chain_FirstLink(ops->margins[ii].axes); link;
+	 link = Chain_NextLink(link)) {
+      Axis *axisPtr = (Axis*)Chain_GetValue(link);
+      axisPtr->printGrids(psPtr);
+    }
+  }
+}
+
+void Graph::printAxesLimits(PSOutput* psPtr)
+{
+  Tcl_HashSearch cursor;
+  for (Tcl_HashEntry* hPtr=Tcl_FirstHashEntry(&axes_.table, &cursor);
+       hPtr; hPtr = Tcl_NextHashEntry(&cursor)) {
+    Axis *axisPtr = (Axis*)Tcl_GetHashValue(hPtr);
+    axisPtr->printLimits(psPtr);
+  }
+}
+
+int Graph::getAxis(Tcl_Obj *objPtr, Axis **axisPtrPtr)
+{
+  *axisPtrPtr = NULL;
+  const char* name = Tcl_GetString(objPtr);
+  if (!name || !name[0])
+    return TCL_ERROR;
+
+  Tcl_HashEntry* hPtr = Tcl_FindHashEntry(&axes_.table, name);
+  if (!hPtr) {
+    Tcl_AppendResult(interp_, "can't find axis \"", name, "\" in \"", 
+		     Tk_PathName(tkwin_), "\"", NULL);
+    return TCL_ERROR;
+  }
+
+  *axisPtrPtr = (Axis*)Tcl_GetHashValue(hPtr);
+  return TCL_OK;
+}
+
+ClientData Graph::axisTag(const char *tagName)
+{
+  int isNew;
+  Tcl_HashEntry *hPtr = Tcl_CreateHashEntry(&axes_.tagTable, tagName, &isNew);
+  return Tcl_GetHashKey(&axes_.tagTable, hPtr);
+}
+
+void Graph::adjustAxes() 
+{
+  GraphOptions* ops = (GraphOptions*)ops_;
+
+  if (ops->inverted) {
+    ops->leftMargin.axes   = axisChain_[0];
+    ops->bottomMargin.axes = axisChain_[1];
+    ops->rightMargin.axes  = axisChain_[2];
+    ops->topMargin.axes    = axisChain_[3];
+  }
+  else {
+    ops->leftMargin.axes   = axisChain_[1];
+    ops->bottomMargin.axes = axisChain_[0];
+    ops->rightMargin.axes  = axisChain_[3];
+    ops->topMargin.axes    = axisChain_[2];
+  }
+}
+
+Point2d Graph::map2D(double x, double y, Axis* xAxis, Axis* yAxis)
+{
+  GraphOptions* ops = (GraphOptions*)ops_;
+
+  Point2d point;
+  if (ops->inverted) {
+    point.x = yAxis->hMap(y);
+    point.y = xAxis->vMap(x);
+  }
+  else {
+    point.x = xAxis->hMap(x);
+    point.y = yAxis->vMap(y);
+  }
+  return point;
+}
+
+Point2d Graph::invMap2D(double x, double y, Axis* xAxis, Axis* yAxis)
+{
+  GraphOptions* ops = (GraphOptions*)ops_;
+
+  Point2d point;
+  if (ops->inverted) {
+    point.x = xAxis->invVMap(y);
+    point.y = yAxis->invHMap(x);
+  }
+  else {
+    point.x = xAxis->invHMap(x);
+    point.y = yAxis->invVMap(y);
+  }
+  return point;
+}
+
+void Graph::resetAxes()
+{
+  // Step 1:  Reset all axes. Initialize the data limits of the axis to
+  // impossible values.
+  Tcl_HashSearch cursor;
+  for (Tcl_HashEntry* hPtr = Tcl_FirstHashEntry(&axes_.table, &cursor);
+       hPtr; hPtr = Tcl_NextHashEntry(&cursor)) {
+    Axis *axisPtr = (Axis*)Tcl_GetHashValue(hPtr);
+    axisPtr->min_ = axisPtr->valueRange_.min = DBL_MAX;
+    axisPtr->max_ = axisPtr->valueRange_.max = -DBL_MAX;
+  }
+
+  // Step 2:  For each element that's to be displayed, get the smallest
+  // and largest data values mapped to each X and Y-axis.  This
+  // will be the axis limits if the user doesn't override them 
+  // with -min and -max options.
+  for (ChainLink* link = Chain_FirstLink(elements_.displayList); link;
+       link = Chain_NextLink(link)) {
+    Region2d exts;
+
+    Element* elemPtr = (Element*)Chain_GetValue(link);
+    ElementOptions* elemops = (ElementOptions*)elemPtr->ops();
+    elemPtr->extents(&exts);
+    elemops->xAxis->getDataLimits(exts.left, exts.right);
+    elemops->yAxis->getDataLimits(exts.top, exts.bottom);
+  }
+
+  // Step 3:  Now that we know the range of data values for each axis,
+  // set axis limits and compute a sweep to generate tick values.
+  for (Tcl_HashEntry* hPtr = Tcl_FirstHashEntry(&axes_.table, &cursor);
+       hPtr; hPtr = Tcl_NextHashEntry(&cursor)) {
+    Axis *axisPtr = (Axis*)Tcl_GetHashValue(hPtr);
+    AxisOptions* ops = (AxisOptions*)axisPtr->ops();
+    axisPtr->fixRange();
+
+    double min = axisPtr->min_;
+    double max = axisPtr->max_;
+    if ((!isnan(axisPtr->scrollMin_)) && (min < axisPtr->scrollMin_))
+      min = axisPtr->scrollMin_;
+
+    if ((!isnan(axisPtr->scrollMax_)) && (max > axisPtr->scrollMax_))
+      max = axisPtr->scrollMax_;
+
+    if (ops->logScale)
+      axisPtr->logScale(min, max);
+    else
+      axisPtr->linearScale(min, max);
+  }
+}
+
+Axis* Graph::nearestAxis(int x, int y)
+{
+  Tcl_HashSearch cursor;
+  for (Tcl_HashEntry* hPtr=Tcl_FirstHashEntry(&axes_.table, &cursor); 
+       hPtr; hPtr = Tcl_NextHashEntry(&cursor)) {
+    Axis *axisPtr = (Axis*)Tcl_GetHashValue(hPtr);
+    AxisOptions* ops = (AxisOptions*)axisPtr->ops();
+    if (ops->hide || !axisPtr->use_)
+      continue;
+
+    if (ops->showTicks) {
+      for (ChainLink* link = Chain_FirstLink(axisPtr->tickLabels_); link;
+	   link = Chain_NextLink(link)) {	
+	TickLabel *labelPtr = (TickLabel*)Chain_GetValue(link);
+	double rw, rh;
+	Point2d bbox[5];
+	getBoundingBox(labelPtr->width, labelPtr->height, ops->tickAngle,
+		       &rw, &rh, bbox);
+	Point2d t;
+	t = anchorPoint(labelPtr->anchorPos.x, labelPtr->anchorPos.y,
+			rw, rh, axisPtr->tickAnchor_);
+	t.x = x - t.x - (rw * 0.5);
+	t.y = y - t.y - (rh * 0.5);
+
+	bbox[4] = bbox[0];
+	if (pointInPolygon(&t, bbox, 5)) {
+	  return axisPtr;
+	}
+      }
+    }
+
+    if (ops->title) {
+      int w, h;
+      double rw, rh;
+      Point2d bbox[5];
+      getTextExtents(ops->titleFont, ops->title, -1, &w, &h);
+      getBoundingBox(w, h, axisPtr->titleAngle_, &rw, &rh, bbox);
+      Point2d t = anchorPoint(axisPtr->titlePos_.x, axisPtr->titlePos_.y, 
+			      rw, rh, axisPtr->titleAnchor_);
+      // Translate the point so that the 0,0 is the upper left 
+      // corner of the bounding box
+      t.x = x - t.x - (rw * 0.5);
+      t.y = y - t.y - (rh * 0.5);
+	    
+      bbox[4] = bbox[0];
+      if (pointInPolygon(&t, bbox, 5)) {
+	return axisPtr;
+      }
+    }
+    if (ops->lineWidth > 0) {
+      if ((x <= axisPtr->right_) && (x >= axisPtr->left_) && 
+	  (y <= axisPtr->bottom_) && (y >= axisPtr->top_)) {
+	return axisPtr;
+      }
+    }
+  }
+
+  return NULL;
+}
+ 
+// Bind
+
+const char** Graph::getTags(ClientData object, ClassId classId, int* num)
+{
+  const char** tags =NULL;
+
+  switch (classId) {
+  case CID_ELEM_BAR:		
+  case CID_ELEM_LINE: 
+    {
+      Element* ptr = (Element*)object;
+      ElementOptions* ops = (ElementOptions*)ptr->ops();
+      int cnt =0;
+      for (const char** pp=ops->tags; *pp; pp++)
+	cnt++;
+      cnt +=2;
+
+      tags = new const char*[cnt];
+      tags[0] = (const char*)elementTag(ptr->name_);
+      tags[1] = (const char*)elementTag(ptr->className());
+      int ii=2;
+      for (const char** pp = ops->tags; *pp; pp++, ii++)
+	tags[ii] = (const char*)elementTag(*pp);
+
+      *num = cnt;
+      return tags;
+    }
+    break;
+  case CID_AXIS_X:
+  case CID_AXIS_Y:
+    {
+      Axis* ptr = (Axis*)object;
+      AxisOptions* ops = (AxisOptions*)ptr->ops();
+      int cnt =0;
+      for (const char** pp=ops->tags; *pp; pp++)
+	cnt++;
+      cnt +=2;
+
+      tags = new const char*[cnt];
+      tags[0] = (const char*)axisTag(ptr->name_);
+      tags[1] = (const char*)axisTag(ptr->className());
+      int ii=2;
+      for (const char** pp = ops->tags; *pp; pp++, ii++)
+	tags[ii] = (const char*)axisTag(*pp);
+
+      *num = cnt;
+      return tags;
+    }
+    break;
+  case CID_MARKER_BITMAP:
+  case CID_MARKER_LINE:
+  case CID_MARKER_POLYGON:
+  case CID_MARKER_TEXT:
+    {
+      Marker* ptr = (Marker*)object;
+      MarkerOptions* ops = (MarkerOptions*)ptr->ops();
+      int cnt =0;
+      for (const char** pp=ops->tags; *pp; pp++)
+	cnt++;
+      cnt +=2;
+
+      tags = new const char*[cnt];
+      tags[0] = (const char*)markerTag(ptr->name_);
+      tags[1] = (const char*)markerTag(ptr->className());
+      int ii=2;
+      for (const char** pp = ops->tags; *pp; pp++, ii++)
+	tags[ii] = (const char*)markerTag(*pp);
+
+      *num = cnt;
+      return tags;
+    }
+    break;
+  default:
+    break;
+  }
+
+  return NULL;
+}
+
+ClientData Graph::pickEntry(int xx, int yy, ClassId* classIdPtr)
+{
+  if (flags & (LAYOUT | MAP_MARKERS)) {
+    *classIdPtr = CID_NONE;
+    return NULL;
+  }
+
+  // Sample coordinate is in one of the graph margins. Can only pick an axis.
+  Region2d exts;
+  extents(&exts);
+  if (xx>=exts.right || xx<exts.left || yy>=exts.bottom || yy<exts.top) {
+    Axis* axisPtr = nearestAxis(xx, yy);
+    if (axisPtr) {
+      *classIdPtr = axisPtr->classId();
+      return axisPtr;
+    }
+  }
+
+  // From top-to-bottom check:
+  // 1. markers drawn on top (-under false).
+  // 2. elements using its display list back to front.
+  // 3. markers drawn under element (-under true).
+  Marker* markerPtr = nearestMarker(xx, yy, 0);
+  if (markerPtr) {
+    *classIdPtr = markerPtr->classId();
+    return markerPtr;
+  }
+
+  GraphOptions* ops = (GraphOptions*)ops_;
+  ClosestSearch* searchPtr = &ops->search;
+  searchPtr->index = -1;
+  searchPtr->x = xx;
+  searchPtr->y = yy;
+  searchPtr->dist = (double)(searchPtr->halo + 1);
+	
+  for (ChainLink* link = Chain_LastLink(elements_.displayList); link;
+       link = Chain_PrevLink(link)) {
+    Element* elemPtr = (Element*)Chain_GetValue(link);
+    ElementOptions* eops = (ElementOptions*)elemPtr->ops();
+    if (eops->hide)
+      continue;
+    elemPtr->closest();
+  }
+
+  // Found an element within the minimum halo distance.
+  if (searchPtr->dist <= (double)searchPtr->halo) {
+    *classIdPtr = searchPtr->elemPtr->classId();
+    return searchPtr->elemPtr;
+  }
+
+  markerPtr = nearestMarker(xx, yy, 1);
+  if (markerPtr) {
+    *classIdPtr = markerPtr->classId();
+    return markerPtr;
+  }
+
+  *classIdPtr = CID_NONE;
+  return NULL;
+}
+
+int Graph::getXY(const char* string, int* xPtr, int* yPtr)
+{
+  if (!string || !*string) {
+    *xPtr = -SHRT_MAX;
+    *yPtr = -SHRT_MAX;
+    return TCL_OK;
+  }
+
+  if (*string != '@') {
+    Tcl_AppendResult(interp_, "bad position \"", string, 
+		     "\": should be \"@x,y\"", (char *)NULL);
+    return TCL_ERROR;
+  }
+
+  char* comma = (char*)strchr(string + 1, ',');
+  if (!comma) {
+    Tcl_AppendResult(interp_, "bad position \"", string, 
+		     "\": should be \"@x,y\"", (char *)NULL);
+    return TCL_ERROR;
+  }
+
+  *comma = '\0';
+  int x, y;
+  int result = ((Tk_GetPixels(interp_, tkwin_, string + 1, &x) == TCL_OK) &&
+		(Tk_GetPixels(interp_, tkwin_, comma + 1, &y) == TCL_OK));
+  *comma = ',';
+  if (!result) {
+    Tcl_AppendResult(interp_, ": can't parse position \"", string, "\"",
+		     (char *)NULL);
+    return TCL_ERROR;
+  }
+
+  *xPtr = x;
+  *yPtr = y;
+  return TCL_OK;
+}
+
+// Graphics
+
+void Graph::drawSegments(Drawable drawable, GC gc, 
+			 Segment2d* segments, int nSegments)
+{
+  for (Segment2d *sp = segments, *send = sp + nSegments; sp < send; sp++)
+    XDrawLine(display_, drawable, gc, (int)sp->p.x, (int)sp->p.y, (int)sp->q.x, (int)sp->q.y);
+}
+
+GC Graph::getPrivateGC(unsigned long gcMask, XGCValues *valuePtr)
+{
+  Pixmap pixmap = None;
+  Drawable drawable = Tk_WindowId(tkwin_);
+  Display* display = Tk_Display(tkwin_);
+  if (drawable == None)
+    drawable = RootWindow(Tk_Display(tkwin_),Tk_ScreenNumber(tkwin_));
+
+  GC gc = XCreateGC(display, drawable, gcMask, valuePtr);
+  if (pixmap != None)
+    Tk_FreePixmap(display, pixmap);
+
+  return gc;
+}
+
+void Graph::freePrivateGC(GC gc)
+{
+  Tk_FreeXId(display_, (XID)XGContextFromGC(gc));
+  XFreeGC(display_, gc);
+}
+
+void Graph::setDashes(GC gc, Dashes* dashesPtr)
+{
+  XSetDashes(display_, gc, dashesPtr->offset, (const char*)dashesPtr->values,
+	     (int)strlen((char*)dashesPtr->values));
+}