About GM Zoom Control ,
(. . .) I think there is no way to implement it gracefully.
Maybe in theory is hard to see it, but the fact is it works well in other virtual tabletops, being a powerful narrative and communicative element not only for maps --which are just a handout between others-- but for images as well.
Even if this can be handled by knowing what are the screen sizes and resolutions of the players by speaking with them, it could be possible to implement some code for automatically adjusting/scaling the "forced zoom" --using the words of Clinton D. for this suggestion-- proportionally to the actual screen resolution of the players.
As GM, I need to know if my players are paying attention to the part of the image that I'm showing to them in a given moment of the game, and that requires me having at least a temporary zoom control for my players. I need to know if me and my group are all in the same page.
Clinton D. said,
I, as the GM, would like to know they're looking at it the same way I am.
Ditto. In occassions it's pointless to take the work of painting (or even using) images or drawing illustrations --game handouts placed in the Roll20 canvas-- with narrative and practical importance for the adventure without the effective ability to control how the viewers (players) are going to receive and see them: this requires not only Shift+Ping --which is really cool albeit insufficient by itself alone-- but also GM Zoom Control .
For instance, as the GM I can place one of such images or maps and arrange it in my own display at 150% zoom level (or greater, by means of ALT+mousewheeling) for achieving a particular focus, and I'll be using Shift+Ping here and there with the purpose of focusing players view as well in particular details according to the narration or depending on their conversation and questions, if meanwhile some of them are actually viewing the image at "wrong/non-concordant zoom levels" of 80% or 100% at full screen mode, with the whole image/area displayed at once. In these cases Shift+Ping does nothing at all for them, I mean, it doesn't displace any focus, so they aren't really getting what I'm sending to them, spoiling GM-players communication at this level.
(And in advance, merely using Fog of War independently of Zoom level, is very far of being a solution here: we are talking of a quick, dynamic way of focusing the attention of our players on the fly, and quickly --in a way, "automatically"-- being able to drop that "forced zoom" without additional and tedious GM preparations when it's not needed anymore.)
Besides, if I set the zoom for the image or map by means of ALT+mousewheeling, there is no way of knowing what is the current zoom percentage, since this is currently disconnected of the zoom level that you can pick in the Roll20 Toolbar. This alone, which is a secondary and related issue, makes impossible to just tell to my players: "Please, set your Zoom level at this percentage that I'm using at the moment."
Even in face to face games, I already have "this feature" in a natural way (using a computer only can enhance it, though): I can point with a pen to a particular section of an image or map and check if my players are paying attention to what I'm doing. In online virtual tabletops without a GM Zoom Control capability there is no way of doing this, but a request like this, along with the current Shift+Ping, would address it.
This feature request is not for annoying your people: think in a video recorded with Camtasia Studio, and how the zoom often changes to focus the attention of the viewers here or there, according to the purposes of the video, for achieving a better communication --but it goes without saying that I'm not asking for any "automatic zoom"!
This is my way of explaining how active control of the images displayed for others is necessary for many GMs --or game mastering styles--, even if not all them are going to use it, and definitely, nor all the time.
The GM would get very tired of tweaking my zoom levels as often as I tweak them. Fact is, what is being asked for would either annoy GMs because the players would be asking for tweaks often or it would cut certain players out of using Roll20.
For example: I have significant light sensitivity. My monitor is turned down to the lowest possible light settings and I still have to wear very dark sunglasses while looking at it. In order to see fine detail I often crank the Zoom up. But I then have to dezoom while moving the map around.
Gauss,
If that is your situation --I'm sure that is annoying, man--, then the thing boils down to the GM knowing his players --it's a point that already has been made. A sensible GM adjusts the use of the game system and related tools for the enjoyment of all people involved. A group that disregards the legitimate concerns or problems of its members, even if it's one of them, isn't deserving your virtual presence. It would be similar to not adjusting the game session to your particular timezone!
if they FIXED the zoom function then the problem that brought this up would no longer be a problem. Zoom should center on the center of the current screen, not on one corner of it. That way when a GM shift+pings the map the player can zoom in and out without the shift+ping location changing.
I agree very much with this: zoom would work much better from the center of the current view. On the other hand, I don't think that the current way of zooming from a corner really "brought this up". Even if Roll20 would handle zoom from the center, the reasons for making this "GM zoom control" feature request remain the same.
P.S. I apologize if I come off a bit forceful here but if this were to be implemented as currently proposed I would be forced to stop using Roll20.
You haven't been rude in any way and you have explained your reasons. That is fine!