On Aug 20, 2010, at 4:40 PM, ext William Martin wrote:
> All,
>
> Is there any way, short of rolling a custom variant, to make OpenLayers add
> ALT text to its images?
There's nothing like this currently. However, you could probably achieve this
by modifying OpenLayers.Util.createImage and
OpenLayers.Util.createAlphaImageDiv,
modifying them to set the alt attribute; this code is used for almost all
image creation in the library, so I expect this would resolve most of the
cases.
-- Chris
> Currently the tile images I'm getting are added something like this:
>
> <img
> style="width: 256px; height: 256px; position: relative;"
> src="{URL snipped}"
> class="olTileImage"
> id="OpenLayersDiv2089">
>
> When my screen reader encounters that, it reads the URL for the image, which
> is:
>
> http://opencache.statkart.no/gatekeeper/gk/gk.open?LAYERS=topo2&FORMAT=image%2Fjpeg&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&SRS=EPSG%3A4326&BBOX=0,56.25,11.25,67.5&WIDTH=256&HEIGHT=256
>
> Keep in mind that it's reading this aloud, so somethin like "1.25" comes out
> as "one point two five". Multiply that pain by 34 for the initially loaded
> tiles.
>
> Then the map controls have HTML like this:
>
> <img
> id="OpenLayers.Control.PanZoomBar_2159_panup_innerImage"
> style="position: relative; width: 18px; height: 18px;"
> src="http://openlayers.org/api/img/north-mini.png";>
>
> Again, a screen reader reads the contents of the SRC attribute because
> there's no ALT text.
>
> Maps are inherently visual/spatial, and therefore of little use to a blind
> visitor. I'd like to set blank ALT text on all the images, thus:
>
> <img
> style="width: 256px; height: 256px; position: relative;"
> src="{URL snipped}"
> class="olTileImage"
> id="OpenLayersDiv2089"
> alt="">
>
> ... which will cause screen readers to silently skip over the image. Then
> I'd add ALT text for the entire map:
>
> <div id="access-note">Image: Map of Norway.</div>
> <div id="map">{OpenLayers would fill in the map here}</div>
>
> That way, any blind visitors would be told that there's a map of Norway
> there, but not troubled with endless, mindless recitations of image SRC
> attributes for a map they can't use. All of my site's content is actually
> available without the maps -- the maps are a useful navigational interface,
> but all the actual site content can be read without them.
>
> So, can I make it add blank ALT text to the tile and control images?
>
> Will Martin
>
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![http://openlayers.org/api/img/north-mini.png"](http://openlayers.org/api/img/north-mini.png"){kind=link}