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The legend indicates to the user how various features are represented on map. The legend indicates the current state of layer: visibility, out of ranges, out of zoom. It allows to control layers and renderers visibility. The layer or renderer entry in legend may be hidden permanently or temporarily.
The legend appearance defined both in layout and project file. In layout file it is declared by object with type="legend"
<![CDATA[
<object type="legend" name="my_legend" bounds="0,52,300,120" align="client"/>
]]>
Note on attribute name. Applet may have several legends with the different list of layers. Name allows to distribute layers among legends. See "legend" attribute for layer.
Besides backcolor and forecolor attributes which describe colours for background and text, the layout entry for legend may have the following attributes:
| ATTRIBUTE | DESRIPTION |
| select_clr | heighlight colour for active layer |
| disabled_clr | disabled layer |
| err_color | layer that can't be loaded |
| net_color | heighlight colour for layer that is downloading |
| separator | defines whether layers in legend will be separated with thin line |
| selection | whether to use select_clr for active layer |
| font_bold | font for layer labels |
| font_plain | font for other labels |
| The attributes below refers to images which describes the state of layer. |
| image_clock | layer is out of time ranges |
| image_zoomin | current map's zoom is less than layer's min zoom range |
| image_zoomout | current map's zoom is more than layer's max zoom range |
| image_network | layer data is downloading |
| image_outext | current map extent is out of layer's extent |
| image_key | password for layer is not resolved |
The objects in project file: layer; renderer and symbol have the attributes which describe their behavior in the legend. All of them have:
showlegend - determines the visibility of object in legend
label - label in legend. If it is not defined, name is utilized. Name is unique object identifier, in contrast to label. Label may be diffretent for different languages.
<![CDATA[
<layer name="Cities" label="Cities of USA">
<label xml:lang="fr">Les villes des Etats-Unis</label>
....
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| ATTRIBUTE | DESRIPTION |
| legend | the name of legend component this layer is represented. Applet may have several legends with the different list of layers |
| legendexpanded | whether to expanded the item on map startup |
| hidelegend_zoom | whether to hide the layer item if layer is out of zoom ranges |
| WrapLayerTitles | whether to wrap labels in legend |
| legendsymbolshape | list of coordinates that allows to define your own shape for legend icon |
| legtype | type of shape 1 - point, 2- line, 3- polyogon |
Besides, if layer's attribute alwaysvisible is true, the checkbox in legend which allows to set layer's visibility will be hidden.
The renderer object may have the attribute AllowOnOffInLegend. It enables the visibility of checkbox for renderer as well as for layer.
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