[PATCH] Brightness/transparency of WMS layer control

[jekhor]

Sometimes WMS layers are too bright and this makes map data layers almost unreadable. Some kind of control WMS layer brightness or transparency will be useful.

[Upliner]

I wrote a patch that allows to change opacity of any layer

[bastiK]

Technically it looks good, but we should improve the GUI a little. My idea would be to merge it somehow with the visibility switch ("eye") because it's a special case of transparency (0% and 100%).

Then some visual feedback would be good. Currently it shows a red cross on the layer icon for 100% transparency. Maybe we can come up with some gradual display?

[Upliner]

Replying to bastiK:

Technically it looks good, but we should improve the GUI a little.

Yes, I should at least draw an icon for new button.

My idea would be to merge it somehow with the visibility switch ("eye") because it's a special case of transparency (0% and 100%).

How do you see it? If you offer something specific, I'll do it.

[bastiK]

Sorry it took so long to answer. I have a bigger change in mind and haven't found time to do a prototype, yet. The basic idea is to make the list entry symbols clickable like in gimp image software. Then you can add a transparency slider button next to the eye button field. We could have an extra column for active layer at the left, so the importance of "active layer" is more clear.

[bastiK]

Ok, I did the changes I had in mind ([3661]).

• My suggestion would be to (practically) remove the visible field from Layer.java. A layer is invisible when the opacity value is 0 and it is opaque when this value is 1.
• A click on show/hide changes the opacity value to 1 in case it is < 1 and to 0 otherwise.
• It should be clearly (and directly) visible, whether a layer is opaque, or just 99% visible. (Because there is a considerable performance loss for half-transparent layers.)
• The easiest way would be to change the new "eye" symbol in the layer list depending on the opacity value:
  • invisible and opaque like it is now.
  • another symbol that represents all opacity values > 0 and < 1. (E.g. the "eye" symbol, but half transparent.)

[bastiK]

Created an icon. Not too good, but maybe its a start...

[Upliner]

I'm sorry for long response too... I don't want remove the visible field because current implementation has a nice feature: it remembers opacity level for hidden layers. I.e I can hide a half-transparent layer and then show it again with same transparency level. I't exteamly convenient for me when viewing the OSM tiles over the Bing imagery. Clicking at eye icon is much easier than moving a slider.

[bastiK]

I see your point. I'd like to show some symbol in the corresponding line of the layer list, whenever the opacity is different from 100%. Any ideas?

[Upliner]

half-transparent dithered eye icon

[Upliner]

Maybe just show a half-transparent dithered eye icon like that? I know that dithering is kind-of out of fashion, I just don't have an another idea...

[bastiK]

ok, this will get in after next release, i'll come up with something...

[bastiK]

Problem with the half transparent eye: User is used to toggle sequence: closed, open, closed, open, ...

now he/she changes transparency and it is: blurred, closed, blurred, closed, ...

so the question would come, how do i get it back to 100% opaque? (Right, move transparency slider to 100%)

[Upliner]

Replying to bastiK:

Problem with the half transparent eye: User is used to toggle sequence: closed, open, closed, open, ...

I don't see a big problem here. If user already have moved a slider why he can't move it again? I think it's a situation where any solutions would have some drawbacks...

My solution seems to be quite efficient: transparency is often used for imagery layers and user usually don't need more than one fully opaque imagery layer, however he/she might want to temorary disable some of half-transparent layers.

[Upliner]

Make the pressed button translucent too

[Upliner]

In [3705/josm]:

applied #5570 - implement layer opacity control