narration-sd
commented
5 years ago Hi Mr. Jón,
I notice @brandonkelly has already set this as a feature request, and I may be able to add some thought since I am completing a feature plugin which adds to Craft's abilities in Live Preview. You may particularly want to look at the point about extra server delays that affect Live Preview strongly, due to xdebug or Craft devMode being enabled. And Brandon may like to look at the lower section, where there's a reason I suggest where your feature could turn out unexpectedly useful.
-
the first is that the normal update delay of Live Preview I observe is on the order of a few hundred milliseconds -- quite fast.
-
This delay is mainly the response time of the server, plus your roundtrip latency on the internet to connection to and from your server. So this may be a factor, from Island, depending on where your server is actually located...and your client also.
-
So when you speak about two or three seconds delay, my first thought is that this internet delay is dominating your problem. In this case, you wouldn't be helped by an in-Craft response time setting, as this could only increase the time and slow updates. However, more below on that.
-
The update speed is also limited by how fast the web browser responds. This is a bit complicated, because browsers don't update instantly on data changes, because calculating their screen layout is expensive. I believe they also will interrupt a current update-in-progress, pause, and calculate again, if a new update comes before the first one has been displayed.
-
This pausing action may be yet a bit more complicated, and the result that I observe is that with a fast local connection, the browser screen updates only with blocks of many characters typed in fast typing, so that update is never instant. This is actually good, as it makes the results you see smoother.
-
Having anything like Craft's devMode turned on, or (particularly strong effects) having xdebug enabled on the server, whether you are using it or not, can really slow down updates. So that's another factor to consider if you are troubleshooting. Be sure to use phpdismod or similar (and restart the appropriate php-fpm service or the server itself afterwards) to completely remove xdebug as a factor, and similarly to set devMode to false on Craft itself, to get a realistic situation for Live Preview update timing.
Ok, and the last point leads to actually a possible reason for this controllable update delay feature, even though I think it will not help you speed up your client's experience. Here's the explanation for that, for which I thought Brandon may be especially interested:
a. It's a general case that as application screens get more complicated, problems with Live Update can arise. When only Twig is used, the screen will arrive all at once, but not necessarily all of its data -- think of image assets, or anything else that might be filled in by Ajax or direct remote calls.
b. As soon as you introduce modern frameworks such as Vue or React into the picture, it gets more complicated. Now you really do have delayable portions of the screen, which proper js app design will keep undisplayed until their data arrive. Vue etc. have features especially for this.
c. The result is that the layout may be unstable early in a screen update -- first some information will show, and later the screen will shift as the rest arrives and is laid out, painted.
c. Especially, this can cause the display to change scroll position, and lose what you were looking at for the Live Preview. Vue has a feature to remember and restore scroll position, which is effective against this, restoring position as the screen becomes built -- mostly.
d. The problem is the 'mostly' comment. My experience so far is that restoration works perfectly when the server is remote, and thus more simply delayed. This is so even or actually especially when the delay is larger, as in your situation at present.
e. However, I've seen a situation where it doesn't always work, where the scroll position can intermittently get lost, and so the Live Preview slip away from showing the information you are interested in. That's when xdebug is active, and browser and server are on the same machine, Windows and using a VM (VMware) at least. Even with a very powerful CPU, it looks like there can be unexpected interruptions, due to interleaving, which cause the browser display and instructions to fall out of sync.
f. Without getting further into this edge case, I don't think it will come up in normal server operation -- but it could; we will have to see. If it did, then the ability to tame the update rate, by using a settable delay as you propose, could be a key to usefulness. So that's my addition to justifying your idea.
Last to say, there is a related feature which can be very helpful in Live Preview, whether it is now on Twig or some future framework, and that is the ability to focus on only one element of multiple content.
The example would be to be editing one slide of a carousel. Then you'll want Live Preview to show you just that slide -- but if it is a carousel, only the first slide will appear 'held' this way. For later slides, you'd have to wait or manually move the slider to see your changes -- each update... This will rapidly become tedious.
Many have noted feature need in this area. The feature I've propose, I believe could make a very smooth solution, which is to give Matrix (and by extension other multiple content fields, including plugin Neo etc.) a 'Solo' button. Then they would work like audio workstation software (and a manual studio console) does, and just 'play' the element you are interested in, until you release Solo.
This will effectively stop a rotating carousel on the slide you want to work on -- and nondestructively so that it resumes again when you are finished. In fact, I'm adding the idea that Solo should automatically cancel on Entry Save, so that it will do that without any editor attention.
The FR issue for Solo is here: https://github.com/craftcms/cms/issues/3116
p.s. Driving a 4WD across from Akureyri to Reykyavik, right after a winter blizzard, was just one of many great experiences once, visiting Island -- many interesting and characterful memories of persons there, so thinking a moment of your good fortune, HerraJòn ;) .
herrajon
Howdy
This is a feature request
One of the most powerful features Craft ships with is its ability to present the live content for its content-editors almost seamlessly on the fly. Live Preview.
Live preview updates new settings/adding new content in something around and about three seconds so the user will not lose the touch in continuing his writings and composure usually based on high Bordeaux consumption and choice of mildly blended tobacco.
Some of them though lag behind bad internet connections and usage of old and rusty hardware. So fast (3secs) update is sometimes something to whine about.
A setting in general.php for the Live-Preview-Refresh-Update-Rate would be a pleasant add on to this almost heavenly software. This would be 'a nice to have'.
Just saying and thank you for reading I would ask you to forgive me for the grammar and spelling but I am shameless.
Yours lovingly Herra Jón