Weird zoom factor vs. logical/physical/data-size

[Jondeen]

Hi!

I'm attempting to get from logical distance to distance measured in data-level values. There are no helper functions for logical->data distance formats, so I tried using following:
physical->logic (screen pixels to fraction of image)
logic (as point offset from zero) ->datapoint.

Below are my results:

var distance=helper.physicalToLogicalDistance(150);

p=new OpenSeadragon.Point(distance,distance);
$.Point {
x: 0.0033450036795040473, 
y: 0.0033450036795040473, 
…}

siz=helper.logicalToDataPoint(p)
$.Point {x: 150, 
y: 195.61916018107618
…}

helper.getZoomFactor()
1

After double checking just now I realise that this is due to the "physicalToLogicalDistance" only looking up x-dimension. As width/height of the data-level image this gives a wrong logical distance for y. In order to look up y you, obviously, need to compare to the y-dimension.
Hence for a proper lookup I'd suggest separate physicalToLogicalDistanceY and physicalToLogicalDistanceX, or possibly a physicalToLogicalDistancePoints(Point A as vector from origo) returning EITHER a {w:__, h: __} object OR the diagonal. Maybe latter makes more sense.

Also a helper "physicalToDataDistance" actually makes more sense, since here only 1 number reflects both dimensions.

If I'm not entirely off the track here I'd be glad to submit a patch, but need to verify I'm not just wrong because of low blood sugar ;-)

[msalsbery]

Hi @Jondeen

I know this is ancient, sorry! Is this something I still need to look into in your opinion?

I'll keep this open until I get to it, but now that I'm modernizing my plugins I'm looking to prioritize issues a bit.

Cheers!

[msalsbery]

Closing this...

The new home for the OpenSeadragon Imaging plugins is here: https://github.com/openseadragon-imaging

If there's still issues, please re-post at the plugin's new home. It's about time this stuff gets fixed!