Missing corner

[bryans]

Hi Tom

On some occasions when I enlarge the picture it sometime blanks off the bottom right hand corner with a rectangle and the symbol for missing picture. (The result an inverted L shape picture.) Reducing the image again, coming out and going back in do not remove it. If I navigate round page I get the full image back, but coming back to bottom right the image is still missing. (I hope you follow that!)

It means as most labels are situated there I loose part of the image and data.

[Tom Humphrey]

Hi Bryan,

Thanks for letting me know about this. I had known it was a possible problem (from errors that appear in the log file), but had never been able to recreate the situation myself, so I'd hoped that all that happened was a user's browser would automatically retry the image load, which would solve the problem.

Unfortunately, your report shows that that is not happening.

When zoomed the herbarium sheets are displayed as a grid of 96 tiles. These are loaded starting in bottom right-hand corner. To save on disk space on the server, I only generate the tiles from the master image when they are first requested. (requesting the first tile triggers the creation of all 96) I'd hoped that this happened fast enough that no delay would be involved, but it seems that creating the tiles can cause the request for the first tile to time-out. Subsequent requests for the remaining images are fine as they exist by then so are sent immediately.

As a short-term fix I'll pregenerate the tiles for all the remaining sheets, - which may also have the added advantage of perhaps speeding up loading marginally. A better solution will need to be found once the project expands and the number of sheets increases.

I'll hopefully run the bulk tile creation tonight, but if not then by tomorrow evening. After that if anyone still sees missing tiles then please follow up this post.

regards,

Tom