[OpenLayers-Dev] Re: [OpenLayers] #2964: Error in Layer.Zoomify
when width or height is evenly divisible by 256
alan at objectivepathology.com
alan at objectivepathology.com
Sat Apr 30 19:47:24 EDT 2011
I was the submitter of the original bug. Fix works for me. I
tried zoomifying an image 16384 x 31 pixels using the
current free Zoomifyer 3.0 from zoomify.com. Note:
coordinates for zoomify tiles are z-x-y.
The result was that all the 2-n-0 tiles were 1 pixel high as
expected. All levels above that would be 0 pixels high
theoretically. However the 1-0-0 tile was 256 x 256, 0-1-0
was 256 x 256. Tiles 0-0-0 and 1-1-0 were completely
missing.
I cannot believe that such an inconsistent result is by
design.
This unfortunate result is at
http://www.objectivepathology.com/ViewerBug/onepixelhigh.htm
In my work with pathology slides I never have a situation
like this. My only issue is the occasional scan where an
edge is exactly 256 pixels wide or high which causes a real
problem.
In conclusion, I'm happy with whatever method people choose
to handle Zoomify tiles where one dimension is zero.
Alan Page
----- Original Message Follows -----
From: "OpenLayers" <trac-20090302 at openlayers.org>
To:
Cc: openlayers-trac at lists.osgeo.org
Subject: Re: [OpenLayers] #2964: Error in Layer.Zoomify when
width or height is evenly divisible by 256
Date: Fri, 29 Apr 2011 13:32:37 -0000
>#2964: Error in Layer.Zoomify when width or height is
>evenly divisible by 256
>---------------------+-------------------------------------
>-----------------
> Reporter: alpage | Owner: euzuro
> Type: bug | Status: new
> Priority: major | Milestone: 2.11 Release
>Component: Layer | Version: 2.10
> Keywords: zoomify | State:
>---------------------+-------------------------------------
>----------------- Changes (by rboulton):
>
> * cc: rboulton (added)
>
>
>Comment:
>
> I've just come across this bug myself, too. Attached is a
>patch I came up
> with (before seeing this ticket) to fix it. It takes a
>slightly different
> approach to the above - rather than checking for a zero
>value, it
> subtracts 1 before the % operation, then adds it again;
>this is almost
> equivalent, but if the actual tierImageSize value was 0 it
>would leave it
> at zero.
>
>--
>Ticket URL:
><http://trac.openlayers.org/ticket/2964#comment:1>
>OpenLayers <http://openlayers.org/> A free AJAX map viewer
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