The first argument selects the <a href="data_addr.html">data</a> to operate on.
<p>
The second argument is either the string <i>global</i> or is a
<a href="layer_addr.html">layer address</a>. The rtree name in the third
argument must correspond to the value of this argument: some of the rtrees
are global, others are per layer.
<p>
The third argument is the name of the rtree to search. The following rtrees
are available:
<p>
<table border=1>
<tr><th> name
    <th> scope
    <th> description

<tr><td> padstack
    <td> global
    <td> padsatck objects (typically used for vias, pins, pads)

<tr><td> subc
    <td> global
    <td> subcircuit objects

<tr><td> rat
    <td> global
    <td> rat lines

<tr><td> line
    <td> layer
    <td> line objects

<tr><td> text
    <td> layer
    <td> text objects

<tr><td> polygon
    <td> layer
    <td> polygon objects

<tr><td> arc
    <td> layer
    <td> arc objects

<tr><td> gfx
    <td> layer
    <td> gfx (bitmap/pixmap) objects

</table>
<p>
Note: rtrees are global to the given scope, e.g. the padstack rtree holds
all padstacks (inside and outside of subcircuits) and a layer's line rtree
holds all line objects that appear on the given layer (inside and outside
of subcircuits).
<p>
Optionally four more arguments may be supplied; when present, these are
4 coordinates that specify the bounding box of the search by the x and y
coordinates of top left and bottom right corners. When these coordinates are
not specified all objects on the rtree is listed.