[feature request] the ability to offset individual layers

[Jack Ireland]

Problem: sometimes the pointing information supplied with the original solar data is not correct. This is often only obvious when two or more images are overlaid. This is a very common situation in solar physics, where the offsets between any two images are often not well known at all.

Solution: it would be nice to implement a tool whereby a single layer in the viewer window can be "nudged" up/down and left/right by say, a single pixel at a time. In the first case, I envisage a button, say "Nudge layer", which pops up - in the viewer window - a little tool of up/down left/right arrows, a re-center button (to reset the nudges to zero), and a "destroy" button to destroy the tool in the viewer window. The user clicks on the arrows, etc, to move the image by a single pixel in the required direction. Note that the "nudge" should be zoom level sensitive, that is, if you are on zoom level 15 and nudge the image 7 pixels to the left, then zoom in to zoom level 10, then this should correspond to a nudge to the left of 7 * 2 ^5 pixels at zoom level 10.

Since this tool can apply to any layer, I also think the tool should be made available in the drop down options available in the Image Layer accordion.

Thanks!

[Patrick Schmiedel (patrick-schmiedel)]

Unfortunately, that will not be possible, I think. That is because the way the tiles arrangement algorithm works is that it assumes all of them are in the same "grid" - so it doesn't have to calculate whether a tile has to be dropped from one side and added to another for each layer. Such a thing should definitely be done on the image data. I imagine we could integrate a way for the user to report a pixel offset, and to retile the image once the offset has been confirmed. But for this, the tiling process would have to be automated. If we could store a URL to the original image in the database for each image, and find a way to start the process and reload the images into the database, this could work...

[Keith Hughitt (keith-hughitt)]

With the method that tiling is handled, this is now possible and would not be difficult to implement. We just need to think of a good interface for such functionality.