I have a RichTextBlock in a ScrollViewer, when the content of the RichTextBlock is too long, there will be very serious performance issue. FYI, the actual height of the RichTextBlock is about 580000. How can I solve this problem?
IMHO, RichTextBox should support Virtualization out of the box. However if you still face performace issue you should consider for third-party vendors like Telerik, Syncfusion or DevExpress.
Related
On one of my vscode installations html hints I working fine (when in html mode I type lin I see this>
on another only the first line and none of the html link hints. What I did
removed all extention
reinstalled visual studio code in place
removed and reinstall visual studion code
I don't see anything suspicious in the debug pane.
How do I repair my VSCode?
Life saver Mark <3. Thanks!
It is a bit fiddly, but indeed the hints box can be sized to a useless single line size. As I see no real use case for this it could be regarded as bug.
Drag the upper or lower border up or down.
To increase success increase zoom size.
I am writing a custom application in C using GTK+2.0 and Cairo. Just for learning purposes (and if successful, then for deployment), I wish to recreate something similar to a overlay toolbar/widget (I am sorry if the terminology is not correct) that appears when a mouse moves over a given area on the window, and disappears when the mouse moves away. The toolbar, as I imagine, should appear on top of the existing widgets without displacing them or altering the widget packing in any way. Is it possible to accomplish? If yes, can you please point me to relevant tutorials/examples and/or outline a way to do the same?
Thanks in advance.
Not sure this is easily doable in GTK2. However, I learned recently that there's the GtkLayout widget which allows pixel exact rendering of widgets, so you can even display some widgets over others. Or you may implement your own container widget.
Please note that since GTK3, there's GtkOverlay which seem to do what you want.
You may also give a look to Clutter, which might allow this. Furthermore, there are projects of merging GTK and Clutter for GTK 4.
The little known GtkHandleBox is capable of doing what you want. I must warn you it is deprecated in GTK+3 because is going against the usual UI direction. Also, the correct positioning will be subject to the windows manager quirks, so I'd expect some issue in this regard.
I'm building a business application which mostly involves tables and other typical form elements. Due to the nature of my application however, I need to place groups of these elements together in a dynamic tree structure which will take up all of the available screen real estate. If real estate is low, there will be some form of smart scrolling allowing users to focus on certain areas of the tree. It could be called an advanced data visualization web form.
Historically, I would have accomplished this by simply using divs and javascript. The canvas element however seems like a more logical way to build my structure. Most uses of the canvas element that I can find are however geared towards graphics and animations (mostly games). Is canvas overkill for this? Will I benefit from using it? Are there alternatives?
Yes, canvas is overkill. It is very much a drawing board and not much more. It is certainly not something that I would expect to create user controls in. Games etc. are more suited as they aren't really standard user controls and wouldn't be expected to behave as such.
A tree structure could easily be implemented with a series of nested uls. Using some JavaScript to expand collapse them by adding and removing classes.
Here is a nice jQuery plugin for you to use or get some ideas of how you could use it.
Edit:
I would stay away from canvas just because of the overhead of the drawing. If you can extend a standard JavaScript treeview to add more functionality this would seem like the best option ot me. Creating controls from scratch in canvas is no small feat.
Edit2 (Post mockup):
This just looks like a multi-part form to me, with hidden forms/areas which are displayed as apropriately. This is far too common to require creating this with canvas.
Canvas is not fully supported in all browsers yet. I recommend using either Jquery or another framework.
I am developing a jQtouch app and each request done via ajax creates a new div in the document for the loaded content. Only a single div is shown at any one time.
How many div's can I have before the app starts getting unresponsive and slow?
Anyone have any ideas on this?
EDIT: Its an iPad app running on Safari, and it would be less than 1000 div's with very basic content
I've had tens of thousands, maybe even a hundred thousand divs, on screen at once.
Performance is either fine, or bad, depending on:
Parsed from HTML or generated Dynamically in JavaScript?
Parsed from HTML means you have a LARGE html source, and this can make browsers hang. Generated in JS is surprisingly fast, even on Internet Explorer, which is the slowest of all browsers for JS.
To be honest, if you really need an absolute answer to this question, then you might want to reconsider your design.
No answer given here will be right, as it depends upon many factors that are specific to your application. E.g. heavy vs. little CSS use, size of the divs, amount of actual graphics rendering required per div, target browser/platform, number of DOM event listeners etc..
Just because you can doesn't mean that you should! :-)
As others have said, there's really no answer.
However, in this talk about the Google Maps API version 3, the speaker brings up the number ten thousand several times, as a basic threshold for browser unhappiness.
http://code.google.com/apis/maps/documentation/javascript/
Without defining a particular environment, it's not possible to answer your question.
And even then, anything anyone tells you is just a guess. You need to do your own testing on real-world configurations with different browsers and hardware. You'll also need to establish some performance benchmarks to decide what "too slow" even means.
I've been able to add several thousand divs without a problem. Depends on what you'll be doing afterwards, of course, and the memory on the client machine. Everyone else is right about that.
As Harpo said, 10K is probably a good ceiling. At one time, I noticed speed problems starting at about 4K divs, but hardware has improved since then.
And, as Neil N said, adding the divs via scripting is better than having a huge HTML source.
And, to answer Harpo's comment, one way to "break it up" so that JS doesn't lock the page and produce a "page is running slowly" error is to call a timer at the end of each "add a div" routine, and the timer in turn calls your "add a div" function again.
Now, MY question is: is it possible to "paint" so that you don't need to add thousands of divs? This can be done with the canvas tag with some browsers, but I don't think it's possible with VML (the excanvas project) on IE. Or is it? I think VML "paints" by adding new elements to the DOM, at which point you may as well use DIVs, unless it's a simple shape.
Is it possible to alter the source of an image via scripting? (the image in the DOM, of course -- not the original image on the server.)
I have a flex/actionscript based project. The project has various view stacks and tab navigators and a few popup windows. The whole thing is managed in pureMVC framework.
When transitioning between various view states, opening a popup, switching a tab, etc, I find the app to exhibit various redraw glitches. Parts of views will be partially drawn or flicker in odd ways. I am fairly confident that the code is working correctly, just seems to be an issue with the overall heaviness of the UI.
Is this a common issue? Are their tried and true techniques to optimize this problem?
In particular what event handlers are available to delay the drawing of view components until the last moment when everything is ready to quickly display to the screen?
Say for example I have a VBox inside a viewstack, and inside this VBox I have a fairly complex datagrid. Can I prepare the datagrid and/or delay the viewstack change until all subview components are in fact ready to be quickly drawn.
What are some possible symptoms to this kind of glitchiness?
just a guess, but this might be related to the flex framework ... i experienced this kind of behaviour too ... i guess it is related to the way flex framework works when carrying out ui tasks ... a lot of deferred instantiations/calls and so on ... when there is a lot going on, the framerate drops and since deferring is framebased, that is probably when the resulting delays become noticable ...
greetz
back2dos
Not sure if this applies to you, but in Firefox/OSX there is a known bug when you make too many javascript calls, and the result is similar as you say... the whole interface shows various glitches and flickers... The solution was to delay the JS calls a bit, so they don't get called too often... this was a serious issue with swfaddress for instance (I think it still is).
http://www.bigspaceship.com/blog/labs/mac-firefox-30-flash-javascript-random-artifacts/
I assume you need the datagrid already attached to its parent container and you are loading data while it's being shown so it constantly updates and renders its content.
Have you simply tried setting its visibility to false until everything is loaded while keeping includeInLayout true and giving it a fixed size?