I need a simple image widget with a support of panning/zooming but unfortunately it appears GTK still does not offer one. I have managed to achieve something similar by using a ScrolledWindow and a Picture backed by a PixBuf (via scaling the PixBuf on demand and a EventControllerMotion to mimic panning), but needless to say that this approach is too slow for smooth zooming on touchpads and uses an insanely high amount of memory due to no tiling.
A suggested approach seems to be using GEGL, but it's not obvious how one is supposed to do that. There seems to be helper libraries for previous versions of GTK (gegl-gtk and gegl-gtk3) but I do not know how one is supposed to use it with GTK 4 applications. And to be honest the documentations are pretty much non-existent.
So I would appreciate some examples/explanations on basics usages of GEGL within GTK (4) applications, or whether if there is a better way.
Related
I have a Flutter app which is becoming more and more janky as time goes by and more features are added. Therefore, is there some utility to make it as smooth as 60FPS?
I know there are some official guides here: https://docs.flutter.dev/perf. However, I have tried to optimize and it is still slow. You know, some things just cannot be fast enough, such as long text, dynamic layout, necessary synchronous computations, etc. Especially when entering a new page or scrolling down a ListView. In addition, I have to use brainpower to find out what is slow and optimize when new features are added, so I hope there is some fully automatic thing which I can drop-in replace and forget it and it just works forever.
Disclaimer: I wrote this package and this is a Q&A style StackOverflow answer.
Yes, I have made it: https://github.com/fzyzcjy/flutter_smooth.
No matter how heavy the tree is to build/layout, it will run at (roughly) full FPS, feel smooth, has zero uncomfortable janks, with neglitable overhead. (I have made some benchmark reports here)
As for usage, for common scenarios, add 6 characters ("Smooth") - ListView becomes SmoothListView, MaterialPageRoute becomes SmoothMaterialPageRoute. For complex cases, use SmoothBuilder(builder: ...) and put whatever you want to be smooth inside the builder.
Roughly speaking about the implementation, it is done by submitting extra frames to the rasterizer every ~16ms, without disturbing all existing code. Therefore, the existing app code will almost not even know the existence of this package.
You need to check how do you use widgets, unnecessary rebuilds, some heavy operations when the widget is creating o rebuilding and it’s recommended to use the performance profiler in the devtools.
I recently chose to switch to a method where my library is totally empty and I embed every image/animation/sound that I need via the Embed tag because it would make my life easier. Having a lot of symbols in my library causes CS5 to run extremely slowly and it was really annoying me.
This was totally fine for making games for computers but I'm currently working on my first iPhone game and I'm noticing that the game starts lagging after a few seconds of play. It's not even a complex game but it does have a lot of images with transparency. So I'm wondering if it would run faster if I forget about the empty library method. I don't really know how that would affect performance but this is the first time that I have to worry about performance. But I am aware of other things that affect performance like transparency and object pooling (just read about this one).
Also the exact same game runs worse on an iPad even though it's a more powerful device?
Having images in your library means that Flash will compress them when it exports the SWF/SWC. This may or may not be desirable.
Using the [Embed] tag means that you can compress them yourself in something like Photoshop and have complete control over the output.
You say that your "game starts lagging after a few seconds of play". This seems to be a memory/design problem rather than whether or not your images are embedded through code or as library symbols. Do some profiling to see where you're spending most of your time, and to check that you don't have a memory leak.
Both using the library and the [Embed] metatags influence performance of your IDE, but they are evaluated at compile time and will produce just about the same byte code.
The performance of your game at runtime is an entirely different issue, though you might be able to get good results by rethinking which images to embed as bitmaps and which to use as vector sprites, how to organize larger images (e.g. creating one basic player sprite and adding individual looks by composition, instead of making each player variation a full sized animation) and trying to reduce the use of transparency and alpha masks.
There are many good articles about improving ActionScript performance both on the AVM2 and on iOS devices. Try searching for "ActionScript optimization runtime" - it should yield plenty of results.
I want to implement a functionality similar to found in Pages app..i.e. text floating around images, image zooming etc.. I have been struggling with this part of my application but no success yet. Would be grateful if someone provides me with some pointers in this regard , like 'Which UIControl should I use?','Help in thinking logic' etc..
Thanx in advance.
Sounds like a fun app to develop.
Some Pointers:
Immediately off the bat, I would say look into creating your own Controls for the floating objects.
I would suggest tackling a smaller project, or maybe a few small to medium size projects. p
Try making a few apps with WinForms or WPF. Also look into XSL:FO.
Immediately off the bat, I would say look into creating your own Controls.
There was a WWDC session that talked about iOS text. I don't think it's violating NDA to say this is going to be a very hard project. No, make that very, very, very hard.
You will probably need to do all UI yourself, and use Core Text for rendering of the text. (But I believe you need to draw selection, etc.) And do the layout yourself.
I have a set of tiled image collections created via Microsoft's Deep Zoom composer, and a Silverlight application that currently consumes them for display via MultiScaleImage - it's all working pretty well - I'd just like to get some experience with iPad programming and
have a couple of ideas for some iPad applications. All my ideas rely on me being able to display/manipulate these tiled image sets (on the iPad).
I just picked up a iMac to facilitate this. I'm not seeing any Objective-C / Cocoa-touch libraries for this though, so am assuming I will have to roll my own. (I saw the Seadragon Ajax component, which is pretty slick, but I'm dealing with collections here, which it doesn't support. I would also like to roll this as a native application just to get the experience.)
The only open source project I found for displaying/manipulating the tiled image sets was Openzoom - a Flash component. I'm not to familiar with ActionScript either (Python, Java, C#, and c are the only languages I have really used), but briefly inspecting the code I didn't really have any issues with it and can probably use it for hints on how to swap the tiles in and out, etc. But, as I'm pretty new to Objective-C/Cocoa-touch, some pointers in the right direction would be appreciated.
1) Are there any other projects out there I am missing, or is OpenZoom my best bet for some reference?
2) Should I be trying to do this display in the UIKit framework, or should I do it as an OpenGL display?
3) Any other suggestions/pointers that I didn't think to ask.
I have just been working on a few apps that rely on tiling large images to allow for deep zooming. I found a couple of examples but the best and most useful for me was Apple's "PhotoScroller" sample code.
It relies on CATiledLayer to handle the tiling. The result is an extremely smooth and responsive interface even with very large images and its not too complex. (A little complex but not too bad).
So to answer your question directly:
PhotoScroller Code
QuartzCore Framework (which is part of the SDK)
There is a great, free little mac app for slicing images into tiles that I use a lot: "Tilen"
In the WWDC 2010 source samples, under iOS, there is a project in the ScrollView Suite called Tiling. It corresponds to WWDC10 session 104. It is probably the best image tiling example out there.
You can take a look at they way RouteMe library does this, the dynamic loading of higher resolution tiles, panning, etc. https://github.com/route-me/route-me
I can't believe nobody has told you about UIScrollview; the UIScrollView component is designed for this very purpose! (think Google Maps, which uses it).
Check out the class reference...
UIScrollView
The delegate method you require is the following....
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
This allows you to check the zoom level, offset etc and then provide a view for zooming. This way you can maintain your 'position' within the tiled landscape independently of the graphics used to represent it.
Don't roll your own UIScrollView, no need to!
Take a look at CATiled Layer. See my answer to a similar question here: Drawing in CATiledLayer with CoreGraphics CGContextDrawImage
What are some suggested "paths" for getting better at drawing in code in Cocoa? I think at this point, that's my biggest weakness. Is drawing in code something general, or Cocoa-specific?
Thanks!
- Jason
The best way is probably practice. Try drawing some simple things at first: a calendar (basically a grid), a custom button, or a digital clock.
Its also worth noting that a lot of 'custom' controls are made from images, so not that much of the drawing is done in code -- the only thing the code does is stitch those images together.
You might want to look at Opacity, a drawing app for OS X (I'm not affiliated with these folks, just discovered the app a few days ago). What sets Opacity apart from other drawing apps is that it can create Quartz code directly from your drawings. Naturally, the generated code is not perfect but in the few days I've been trying this app I've found it to be quite helpful in understanding how to use Quartz more effectively.
Drawing in code is need for creating custom controls no matter what UI toolkit you pick. Drawing in code certainly has its advantage, for example the application/framework that you are building is really lightweight come production time, cause there will be lot let resources(images/fonts/etc) to worry about.
Also if a problem arises changing drawing in code is a lot easier than to redo code and images together.
If you are doing Cocoa drawing start by looking at source code of BGHudAppKit and reading Cocoa Drawing Guide by Apple.
I'm in the same boat as you; I'd like to learn more about drawing code.
It's a big document, but the Quartz 2D programming guide on the developer website seems like a good place to start from. They introduce Graphics Contexts and Paths and include plenty of images.
There's also a book referenced in that document, Programming With Quartz: 2D and PDF Graphics in Mac OS X which looks good. The APIs for iPhone and OSX are almost identical, so there's no problem using a Mac OSX book.
So I'd suggest start with the Apple documentation (you don't need to read past the section on CGLayer drawing), try some sample code and figure out how it's working. Then move on to either that book or find more sample code on the web. Good luck!