I have been searching around and it looks like this question has been asked quite a few times in various places with no answers or responses. That means that I can't be the only one experiencing this.
There is always a delay in the scrolling when you try to scroll a list or panel for the first time. After the first time you scroll a list or panel, there is no longer any delay. Is there a way I can simulate this "first touch" in an effort to remove the delay when attempting to scroll a list or panel for the first time?
I've been looking through the ScrollView and Scroller code and have not been able to find a point where anything heavy or expensive is happening on a first touch.
Any help or direction on how to remedy this would be greatly appreciated.
Thanks!
You can open the Chrome/Safari developer tools and start profiling("Profiles" tab) to see if there is any JavaScript code that is performing badly and causing the hang.
If it's not code that hangs, it might be a web browser issue (e.g. image cache allocation), for example due to the first time that things dynamically change in your web app.
It's also important to try and compare platforms and see if they have the same issue.
It's also often helpful if you specify the Sencha version (I assume 1.x?) and the platform(s) you've had the issue with. iOS/Android/PC can often react quite differently.
Related
According to a Qt blog post from 2011, there is supposed to be an environment variable QML_FLASH_MODE that can be set to 1 to see which areas of a QML application are being repainted.
I have set this variable for a Qt Quick 2 application that I'm writing and there is no visual difference to running the application without this variable.
Is there any other way to see QML redrawing activity? I'm trying to troubleshoot performance issues.
It looks like QML_FLASH_MODE was removed in this commit as part of refactoring to support separate rendering loops per window. Reason why it was removed is not obvious, but anyway its gone now.
If you think QML_FLASH_MODE will help you to analyse your scene, you can always get back to Qt 5.1.1 where it still should be present.
On the other hand, to visually analyse scene is not always efficient. I suggest to use qtcreator's profiling. Take a look at property bindings that reevaluated just before painting happens. This should help you to figure which property changes have triggered redraw and could give you some hints on how to optimise your scene.
If you just want to count fps or log when frames being painted, check QQuickWindow::frameSwapped signal.
So my current app project is a camera based app and all is going well so far but I have run in to a weird little issue and don't know if there's something basic i'm missing or if it's something more complex.
When I run my app on the iPad in landscape mode (right hand home button), the right end of the screen doesn't recognise touch down events, though if an item is spread across the border (half recognising touches, half not) and you press on the good half and drag, it still recognises the touch and also recognises the touch up event when you let go. Through testing, I worked out that it works fine up to pixel 768 so this makes me think that one of the views thinks that the application is still running in portrait. But then when I run it in portrait, the bottom section (same portion) doesn't work either.
I have looked at another couple of posts on SO:
Article 1
Article 2
I have tried the fixes they say, but have had no luck as of yet. It may be something to do with the fact I have various different views created both programatically and in the interface builder and somewhere along the way, something isn't being initialised correctly but I have tried changing them all, I may have missed some though.
If anybody can shed any light on my situation, that would be greatly appreciated.
Thanks,
Matt
I think the problem has something to do with autoresizing mask. Have you set this? Try to set the background color of all views to see where they are.
I've been trying to render the entire canvas in an IWebBrowser2 control to a bitmap. IViewObject::Draw seems to be the most promising approach, but I can't get it to render anything that would requires a scroll to show. While I could automate the scrolling and stitch the images together, this would look weird with any fixed position elements. Is this even doable?
Additionally, I've tried to set the controller's size to one that would allow the entire contents to display without needing to scroll, but Windows caps the max size to the current screen resolution, so that only gets me partially there.
Any help would be much appreciated. I'm currently doing this in the context of Win7 and IE8, but I don't think that should matter much.
Sorry it took so long for me to follow up with the answer to this.
I wrote up an article detailing how to trick Windows into allowing you to resize a window larger than the virtual screen resolution, allowing functions like PrintWindow or IViewObject::Draw to capture the entire client area (i.e., the browser canvas).
http://nirvdrum.com/2010/03/25/how-to-take-full-page-or-full-canvas-screenshots-in-windows.html
An actual implementation of the technique can be found in my SnapsIE repository on GitHub (username: nirvdrum). Unfortunately I don't have enough karma to post two hyperlinks. The repository is linked from the article though.
It is very likely an IE optimisation that avoid to draw more than required. You might be able to scroll the window and call IViewObject::Draw in a loop without any animation occuring ?
I'm surprised that Windows caps the max size to the current screen resolution. Are you sure about that ?
I have a problem not sure how to solve this. Hmm I am developing a game, a multi touch game, I already can make everything working fine, except a small issue that I want to show messages on the playing screen, each time the player makes actions. like his finger moves right the message says : "this finger moving right" nicely at the bottom of the screen, then if the finger move left, then it says the his finger moves left... something like that, can anyone show me how. I am using Cocos2D , it shall be much easier in Cocoa.
Thanks a alot for any help.
You'll probably need to be more specific with your question, but for now, here's a general answer:
Handling touch events on the iPhone and Handling touch ("trackpad") events on the Mac.
You'll receive and process the events per the above, then you'll display the results somehow. For testing, you'll probably just want to log the results to the console. For the final version, you might have a label or even a custom view that draws the "instruction" in some fancier way. If the latter is the case, you'll want to read up on custom views and drawing for whichever platform you're using (or both).
I've built a screensaver for Leopard which utilises core-animation. It doesn't do anything overly complicated; uses a tree of CALayers and CATextLayers to produce a "table" of data in the following structure:
- root
› maincontainer
› subcontainer
› row [multiple]
› cell [multiple]
› text layer
At most there are 50 CALayers rendered on the screen at any one time.
Once I've built the "table", I'm adding animating the "subcontainer" into view using CABasicAnimation. Again, I'm not doing anything fancy - just a simple fade-in.
The problem is that while the animation does happen its painful to watch. It's jerky on my development machine which is a 3.06Ghz iMac with 4GB of RAM, and seems to chop the animation into 10 steps rather than showing a gradual change.
It gets worse on the ppc mac-mini the screensaver is targeted for; it refuses to even play the animation, generally "tweening" from the beginning of the animation (0% opacity) to half-way (50%) then completing.
I'm relatively new to ObjectiveC and my experience is based on using garbage-collected environments, but I can't believe I'm leaking enough memory at the point the screensaver starts to cause such problems.
Also, I'm quite sure its not a problem with the hardware. I've tested the built-in screensavers which use core-animation, and downloaded a few free CA-based for comparison, and they run without issue on both machines.
Information is pretty thin on Google with regards to using CA in screensavers, or using CA in general for that matter, and advice/tutorials on profiling/troubling screensavers seems to be non-existant. So any help the community can provide would be well welcomed!
--- UPDATE ---
Seems as though implicit animations help smooth things out a little. Still kinda jerky, but not as bad as trying to animate everything with explicit animations as in my solution.
There isn't much special about a screen saver. I assume you've started with the Core Animation Programming Guide? Running it through Instruments will give you a lot of information about where you're taking too much time.
The code you're using to do the fade-in would be useful. For what you're describing, you don't even need CABasicAnimation; you can just set the animatable properties of the layers, and they by default animate. Make sure you've read up on Implicit Animations. The rest of that page is probably of use as well.
Most of your job in CoreAnimation is getting out of the way. I generally knows what it's doing, and most problems come from second guessing it to trying to tell it too much.