Function msDrawLegend

maplegend.c:452–607

** Creates a GD image of a legend for a specific map. msDrawLegend() ** respects the current scale, and classes without a name are not ** added to the legend. ** ** scale_independent is used for WMS GetLegendGraphic. It should be set to ** MS_FALSE in most cases. If it is set to MS_TRUE then the layers' minscale ** and maxscale are ignored and layers that are currently out of scale still ** show u

** show up in the legend.
*/
imageObj *msDrawLegend(mapObj *map, int scale_independent)
{
  int i,j; /* loop counters */
  pointObj pnt;
  int size_x, size_y=0;
  layerObj *lp;  
  rectObj rect;
  imageObj *image = NULL;
  outputFormatObj *format = NULL;
  char *text;

  struct legend_struct {
    int height;
    char *transformedText;
    layerObj *layer;
    classObj *theclass;
    struct legend_struct* pred;
  };
  typedef struct legend_struct legendlabel;
  legendlabel *head=NULL,*cur=NULL;
  
  if(!MS_RENDERER_PLUGIN(map->outputformat)) {
      msSetError(MS_MISCERR,"unsupported output format","msDrawLegend()");
      return NULL;
  }
  if(msValidateContexts(map) != MS_SUCCESS) return NULL; /* make sure there are no recursive REQUIRES or LABELREQUIRES expressions */
  if(msLegendCalcSize(map, scale_independent, &size_x, &size_y, NULL, 0) != MS_SUCCESS) return NULL;

  /*
   * step through all map classes, and for each one that will be displayed
   * keep a reference to its label size and text
   */
  for(i=0; i<map->numlayers; i++) {
    lp = (GET_LAYER(map, map->layerorder[i]));

    if((lp->status == MS_OFF) || (lp->type == MS_LAYER_QUERY)) /* skip it */
      continue;
        
    if(!scale_independent && map->scaledenom > 0) {
      if((lp->maxscaledenom > 0) && (map->scaledenom > lp->maxscaledenom)) continue;
      if((lp->minscaledenom > 0) && (map->scaledenom <= lp->minscaledenom)) continue;
    }

    if(!scale_independent && lp->maxscaledenom <=0 && lp->minscaledenom <=0) {
      if((lp->maxgeowidth > 0) && ((map->extent.maxx - map->extent.minx) > lp->maxgeowidth)) continue;
      if((lp->mingeowidth > 0) && ((map->extent.maxx - map->extent.minx) < lp->mingeowidth)) continue;
    }

    for(j=lp->numclasses-1;j>=0;j--) {
      text = lp->class[j]->title?lp->class[j]->title:lp->class[j]->name; /* point to the right legend text, title takes precedence */
      if(!text) continue; /* skip it */

      /* skip the class if the classgroup is defined */
      if(lp->classgroup && (lp->class[j]->group == NULL || strcasecmp(lp->class[j]->group, lp->classgroup) != 0))
        continue;

      if(!scale_independent && map->scaledenom > 0) {  /* verify class scale here */
        if((lp->class[j]->maxscaledenom > 0) && (map->scaledenom > lp->class[j]->maxscaledenom)) continue;