measureBasedView: fix image zoom levels in (IIIF)

[riedde]

Relates to #262

When changing the zoom level in measureBasedView the image will be reloaded with the wrong dimensions. See here

Here also the footer is missing. This is problematic, because the dimensions are different then and the measures are moving caused by this.

@roewenstrunk I thought we had fixed this for 1.0.0-beta.4, can you imagine, why this occurs here again? Could this problem be caused by the IIIF-providing institution?

[riedde]

Just for documentation:

As the images below show separate images are loaded on specific breakpoints (see URLs). One loaded the images will be displayed dependent from the zoom level but the measure zones are static (not recalculated).

[riedde]

Resolved! This problem occurs if the encoded dimensions of the images are wrong. I worked with the Vertaktoid (4.0.0) and it encoded wrong dimensions. After correcting them and rescaling the zones, everything worked fine!

[riedde]

Reopening, because it seems to be resolved, but there is a little adjustment of the image when zooming in and this causes a small shift of the image behind the zone. Not critical but must be resolved some day!

[riedde]

The problem concerning the last comment is that the footer isn't available on every zoom level. If it is missing the image height is different and then the measures are modified: In IIIF the dimensions are relative to the image, in edirom they are static coordinates.

[riedde]

One a special point the image fall is changing from full to snippet (see URL). The snippet has different dimensions -.-

[bwbohl]

So if I gather correctly this is really an issue with the institution providing the images, right?

[bwbohl]

pinging @riedde

[riedde]

I think the solution could be that the view checks if the dimensions of the delivered image are the same than the encoded ones. If not we need a scaling function. Can'T do that on my own at the moment.