[OpenLayers-Users] OpenLayers.Control.ScaleLine : Add a coefficient

[Micka]

Hey,


Well, I've gotten the source code of this module, so now i'm trying to add a
coeficient K .


The goal is to give the possibility to adjust the scaleline.

For that, I thought that we can add two function on this module :


   1. float calculateTheCoefficient(float length, int pixels );      //
   length in meter , pixels number of pixels that the length represent
   2. void setTheCoefficient ( float k );


The first function will calculate the coefficient with the actual resolution
and the length/pixels .
the second function will save the coefficient for the update function() .


What do you think ?


My problem, is that i don't know how to do code the first function .......






   update: function() {
        var res = this.map.getResolution();
*        res*= k;*
        if (!res) {
            return;
        }

        // convert maxWidth to map units
            var maxSizeData = this.maxWidth * res;

        // decide whether to use large or small scale units
            var topUnits;
            if(maxSizeData > 0.1) {
              topUnits = this.topOutUnits;
            } else {
              topUnits = this.topInUnits;
            }

        // and to map units units
            var curMapUnits = this.map.units;
            var inches = OpenLayers.INCHES_PER_UNIT;
            var topMax = maxSizeData * inches[curMapUnits] /
inches[topUnits];

            // now trim this down to useful block length
            var topRounded = this.getBarLen(topMax);

            // and back to display units
            topMax = topRounded / inches[curMapUnits] * inches[topUnits];

            // and to pixel units
            var topPx = topMax / res;

            // now set the pixel widths
            this.eTop.style.width = Math.round(topPx) + "px";

            // and the values inside them
            this.eTop.innerHTML = topRounded + " " + topUnits;
        },

        CLASS_NAME: "OpenLayers.Control.ScaleLine"
    }





On Thu, Mar 24, 2011 at 3:03 PM, mickal <mickamusset at gmail.com> wrote:

> Hi,
>
> The scale that the module displayed to me is not right, I mean :
>
> 50 pixel => 1000km
> but in reality :
> 50 pixel => 100 m
>
> is it possible to add a coefficient to this module ?  to adjust the scale
> that it displayed.
>
>
> Because otherwise I have to change my map, and this process is very long.
>
>
> thx,
>
> --
> View this message in context:
> http://osgeo-org.1803224.n2.nabble.com/OpenLayers-Control-ScaleLine-Add-a-coefficient-tp6204219p6204219.html
> Sent from the OpenLayers Users mailing list archive at Nabble.com.
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