// Before placing a new label we need to see if the label overlaps over // previously placed labels. This algorithm will be refactored a bit to try // NE SE SW NW placements in the future. void try_and_insert_placement(simplet_lithograph_t *litho, PangoLayout *layout, double x, double y){ int width, height; // Find the computed width and height of a layout in image pixels pango_layout_get_pixel_size(layout, &width, &height); simplet_bounds_t *bounds = simplet_bounds_new(); if(!bounds) return; // Create a bounds to test for intersection simplet_bounds_extend(bounds, floor(x - width / 2), floor(y - height / 2)); simplet_bounds_extend(bounds, floor(x + width / 2), floor(y + height / 2)); // Iterate through the list of already placed labels and check for overlaps. simplet_listiter_t *iter = simplet_get_list_iter(litho->placements); placement_t *placement; while((placement = (placement_t *) simplet_list_next(iter))){ if(simplet_bounds_intersects(placement->bounds, bounds)){ simplet_bounds_free(bounds); g_object_unref(layout); simplet_list_iter_free(iter); return; } } // If we get here we can create and insert a new placement. placement_t *plc = placement_new(layout, bounds); if(!plc) { simplet_bounds_free(bounds); g_object_unref(layout); return; } simplet_list_push(litho->placements, (void *)plc); }
// Create a bounds from the Convex Hull of an OGR Geometry. simplet_bounds_t* simplet_bounds_from_ogr(OGRGeometryH geom){ OGRGeometryH hull; // Grab the Convex Hull if(!(hull = OGR_G_ConvexHull(geom))) return NULL; // Create the bounds. simplet_bounds_t *bounds; if(!(bounds = simplet_bounds_new())){ OGR_G_DestroyGeometry(hull); return NULL; } // Extend the bounds by adding the points from the Convex Hull. double x, y; for(int i = 0; i < OGR_G_GetGeometryCount(hull); i++){ OGRGeometryH subgeom = OGR_G_GetGeometryRef(hull, i); if(subgeom == NULL) continue; for(int j = 0; j < OGR_G_GetPointCount(subgeom); j++){ OGR_G_GetPoint(subgeom, j, &x, &y, NULL); simplet_bounds_extend(bounds, x, y); } } OGR_G_DestroyGeometry(hull); return bounds; }