# GeoExt

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- `GeoExt.data.PrintProvider`

# `GeoExt.data.PrintProvider`

Extends
  - Ext.util.Observable

class `GeoExt.data.``PrintProvider`

Provides an interface to a Mapfish or GeoServer print module. For printing, one or more instances of `GeoExt.data.PrintPage` are also required to tell the PrintProvider about the scale and extent (and optionally rotation) of the page(s) we want to print.

## Example Use

Minimal code to print as much of the current map extent as possible as soon as the print service capabilities are loaded, using the first layout reported by the print service:

    var mapPanel = new GeoExt.MapPanel({
        renderTo: "mappanel",
        layers: [new OpenLayers.Layer.WMS("wms", "/geoserver/wms",
            {layers: "topp:tasmania_state_boundaries"})],
        center: [146.56, -41.56],
        zoom: 7
    });
    var printProvider = new GeoExt.data.PrintProvider({
        url: "/geoserver/pdf",
        listeners: {
            "loadcapabilities": function() {
                var printPage = new GeoExt.data.PrintPage({
                    printProvider: printProvider
                });
                printPage.fit(mapPanel, true);
                printProvider.print(mapPanel, printPage);
            }
        }
    });

## Config Options

Configuration properties in addition to those listed for Ext.util.Observable.

`autoLoad`
  `Boolean` If set to true, the capabilities will be loaded upon instance creation, and `loadCapabilities` does not need to be called manually. Setting this when `capabilities` and no `url` is provided has no effect. Default is false.

`baseParams`
  `Object` Key-value pairs of base params to be add to every request to the service. Optional.

`capabilities`
  `Object` Capabilities of the print service. Only required if `url` is not provided. This is the object returned by the `info.json` endpoint of the print service, and is usually obtained by including a script tag pointing to http://path/to/printservice/info.json?var=myvar in the head of the html document, making the capabilities accessible as `window.myvar`. This property should be used when no local print service or proxy is available, or when you do not listen for the `loadcapabilities` events before creating components that require the PrintProvider’s capabilities to be available.

`encoding`
  `String` The encoding to set in the headers when requesting the print service. Prevent character encoding issues, especially when using IE. Default is retrieved from document charset or characterSet if existing or `UTF-8` if not.

`method`
  `String` Either `POST` or `GET` (case-sensitive). Method to use when sending print requests to the servlet. If the print service is at the same origin as the application (or accessible via proxy), then `POST` is recommended. Use `GET` when accessing a remote print service with no proxy available, but expect issues with character encoding and URLs exceeding the maximum length. Default is `POST`.

`timeout`
  `Number` Timeout of the POST Ajax request used for the print request (in milliseconds). Default of 30 seconds. Has no effect if `method` is set to `GET`.

`url`
  `String` Base url of the print service. Only required if `capabilities` is not provided. This is usually something like http://path/to/mapfish/print for Mapfish, and http://path/to/geoserver/pdf for GeoServer with the printing extension installed. This property requires that the print service is at the same origin as the application (or accessible via proxy).

## Public Properties

Public properties in addition to those listed for Ext.util.Observable.

`PrintProvider.``customParams`
  `Object` Key-value pairs of custom data to be sent to the print service. Optional. This is e.g. useful for complex layout definitions on the server side that require additional parameters.

`PrintProvider.``dpi`
  `Ext.data.Record` the record for the currently used resolution. Read-only, use `setDpi` to set the value.

`PrintProvider.``dpis`

  `Ext.data.JsonStore` read-only. A store representing the dpis available.

  Fields of records in this store:

  - name - `String` the name of the dpi
  - value - `Float` the dots per inch

`PrintProvider.``layout`
  `Ext.data.Record` the record of the currently used layout. Read-only, use `setLayout` to set the value.

`PrintProvider.``layouts`

  `Ext.data.JsonStore` read-only. A store representing the layouts available.

  Fields of records in this store:

  - name - `String` the name of the layout
  - size - `Object` width and height of the map in points
  - rotation - `Boolean` indicates if rotation is supported

`PrintProvider.``scales`

  `Ext.data.JsonStore` read-only. A store representing the scales available.

  Fields of records in this store:

  - name - `String` the name of the scale
  - value - `Float` the scale denominator

## Public Methods

Public methods in addition to those listed for Ext.util.Observable.

`PrintProvider.``loadCapabilities`()
  Loads the capabilities from the print service. If this instance is configured with either `capabilities` or a `url` and `autoLoad` set to true, then this method does not need to be called from the application.

`PrintProvider.``print`()

  Parameters: | map – `GeoExt.MapPanel` or `OpenLayers.Map` The map to print. pages – `Array` of `GeoExt.data.PrintPage` or `GeoExt.data.PrintPage` page(s) to print. options – `Object` of additional options, see below.

  Sends the print command to the print service and opens a new window with the resulting PDF.

  Valid properties for the `options` argument:

  > - `legend` - `GeoExt.LegendPanel` If provided, the legend will be added to the print document. For the printed result to look like the LegendPanel, the following `!legends` block should be included in the `items` of your page layout in the print module’s configuration file:

  >       - !legends
  >           maxIconWidth: 0
  >           maxIconHeight: 0
  >           classIndentation: 0
  >           layerSpace: 5
  >           layerFontSize: 10

  > - `overview` - `OpenLayers.Control.OverviewMap` If provided, the layers for the overview map in the printout will be taken from the OverviewMap control. If not provided, the print service will use the main map’s layers for the overview map. Applies only for layouts configured to print an overview map.

`PrintProvider.``setDpi`()

  Parameter: | dpi – `Ext.data.Record` the dpi record.

  Sets the dpi for this printProvider.

`PrintProvider.``setLayout`()

  Parameter: | layout – `Ext.data.Record` the record of the layout.

  Sets the layout for this printProvider.

## Events

Events in addition to those listed for Ext.util.Observable.

`beforeencodelayer`

  Triggered before a layer is encoded. This can be used to exclude layers from the printing, by having the listener return false.

  Listener arguments:

  - printProvider - `GeoExt.data.PrintProvider` this PrintProvider
  - layer - `OpenLayers.Layer` the layer which is about to be encoded.

`beforeprint`

  Triggered when the print method is called. TODO: rename this event to beforeencode

  Listener arguments:

  - printProvider - `GeoExt.data.PrintProvider` this PrintProvider
  - map - `OpenLayers.Map` the map being printed
  - pages - Array of `GeoExt.data.PrintPage` the print pages being printed
  - options - `Object` the options to the print command

`dpichange`

  Triggered when the dpi value is changed.

  Listener arguments:

  - printProvider - `GeoExt.data.PrintProvider` this PrintProvider
  - dpi - `Ext.data.Record` the new dpi record

`encodelayer`

  Triggered when a layer is encoded. This can be used to modify the encoded low-level layer object that will be sent to the print service.

  Listener arguments:

  - printProvider - `GeoExt.data.PrintProvider` this PrintProvider
  - layer - `OpenLayers.Layer` the layer which is about to be encoded.
  - encodedLayer - `Object` the encoded layer that will be sent to the print service.

`layoutchange`

  Triggered when the layout is changed.

  Listener arguments:

  - printProvider - `GeoExt.data.PrintProvider` this PrintProvider
  - layout - `Ext.data.Record` the new layout

`loadcapabilities`

  Triggered when the capabilities have finished loading. This event will only fire when `capabilities` is not configured.

  Listener arguments:

  - printProvider - `GeoExt.data.PrintProvider` this PrintProvider
  - capabilities - `Object` the capabilities

`print`

  Triggered when the print document is opened.

  Listener arguments:

  - printProvider - `GeoExt.data.PrintProvider` this PrintProvider
  - url - `String` the url of the print document

`printexception`

  Triggered when using the `POST` method, when the print backend returns an exception.

  Listener arguments:

  - printProvider - `GeoExt.data.PrintProvider` this PrintProvider
  - response - `Object` the response object of the XHR

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