I want to create 2 separate layers using quartz 2D. Can i handle there redraw methods separately? so that i can redraw 1 layer without redrawing the whole screen or other layers.
Is it possible? any code sample?
Yes, it's possible and easy to do. Use the QuartzViewController/QuartzView classes in Apple's QuartzDemo iPhone sample code to get started. Use subclasses if you want specialized behavior.
See here:
http://developer.apple.com/IPhone/library/samplecode/QuartzDemo/Introduction/Intro.html
I'm coming from the Mac world. On the Mac, you'd create two overlapping views and deal with it that way. On the iPhone, I suspect you do the same: create two UIViews and then handle the two redraw methods independently. I believe overlapping views are fine on the iPhone (just as they are now on the Mac since 10.5).
Related
I would like to implement a new CATransition.
For example, let's say I would like to do this effect: a n by m array of two sided layers that have a portion of the source image on one side, and the a portion of the destination image on the other side. Each layer would rotate around its x axis by 180 degrees to reveal the other side. Can such a logic (animated CALayers) be used for a CATransition ?
I don't think you can do this. The only way to customize CATransition beyond the built-in types and subtypes, is by using a CIFilter(from iOS 5.0 or OSX 10.5). And the only way to create a custom CIFilter beyond chaining and configuring built-in filters is, according to the doc :
You can subclass CIFilter in order to create:
A filter by chaining together two or more built-in Core Image filters (iOS and OS X)
A custom filter that uses an image processing kernel that you write (OS X only)
So doing this based on CALayer animations is not possible.
On OSX this should be managable with some math work, but not directly using CALayers animations. In iOS this is simply not possible.
Instead of doing a CATransition you could achieve the same effect by using layers directly, but obviously it would not integrate as easily in your UI code.
I have written a transition effect like you describe, but it was not a CATransition. Instead, I created my own method to handle view transitions, and invoke that.
My transition cut the two views into vertical slices, and then did an animation where I start rotating the slices around their Y axes, starting with the left-most slice and working to the right, which creates a cool-looking cascade effect. It took quite a bit of work with CAAnimationGroup obbjects, plus using beginTime for each strip's animation to stagger it's beginning. That one transition animation took about 5 pages of code.
I've created many types of interfaces using the Cocoa API — some of them using documented basic animation techniques and others simply by experimenting (such as placing an animated .gif inside an NSImage class) — which had somewhat catastrophic consequences. The question I have is what is the correct or the most effective way to create an animated and dynamic GUI so that it runs optimally and properly?
The closest example I can think of that would use a similar type of animation would be something one might see done in flash on any number of interactive websites or interfaces. I'm sure flash can be used in a Cocoa app, although if there is a way to achieve a similar result without re-inventing the wheel, or having to use 3rd party SDKs, I would love to get some input. Keep in mind I'm not just thinking of animation for games, iOS, etc. — I'm most interested in an animated GUI for Mac OS X, and making it 'flow' as one might interact in it.
If u wish to add many graphics animations, then go for OpenGLES based xcode project for iOS. That helps u to reduce performance problem. You can render each of the frames in gif as 2D texture.
I would recommend that you take a look at Core Animation. It is Apples framework for hardware accelerated animations for both OS X and iOS. It's built for making animated GUIs.
You can animate the property changes for things like position, opacity, color, transforms etc and also animate gradients with CAGradientLayer and animate non-rectagunal shapes using CAShapeLayer and a lot of other things.
A good resource to get you started is the Core Animation Programming Guide.
So I want to have a view (NSView, NSOpenGLView, something CG related?) which basically displays a map. Such as:
http://dump.tanaris4.com/map.png
Obviously that looks horrible, but I did it using an NSView, and it draws SO slow. Clearly not designed for this.
I just need to allow users to click on the individual (x,y) coordinates to make changes, and zoom into a certain area (to see it better).
Should I go the OpenGL route? And if so - any suggestions as to how to get started? (I was able to follow the guide to draw a triangle, so that's good).
I did find this post on zooming in an NSView: How to implement zoom/scale in a Cocoa AppKit-application
My concern is if I'm drawing over 6000 coordinates and the lines connecting them, this isn't efficient at all.
I don't think using OpenGL would be of any good here. The problem does not seem to be the actual painting, but rather the rendering strategy. You would need a scene graph of some kind to dynamically handle level of detail and culling.
Qt has all this packaged in a nice class class QGraphicsScene (see http://doc.qt.nokia.com/latest/qgraphicsscene.html for reference, and http://doc.qt.nokia.com/main-snapshot/demos-chip.html for an example).
Some basic concepts you should consider using:
http://en.wikipedia.org/wiki/Scene_graph
http://en.wikipedia.org/wiki/Quadtree
http://en.wikipedia.org/wiki/Level_of_detail
Try using core graphics for this, really there is so much that could be done. Watch the video Practical Drawing for iOS Developers from WWDC 2011 and it should give an over view of what can be done with CG.
I believe even CoreGraphics will suffice for what you want to achieve, and that should work under a UIView if you draw the rectangle of your view completely under the DrawRect method of your UIView (you must overload this method). Please see the UIView Class Reference. I have a mobile application that logs points on the UIMapKit, kind of like Nike+, and it certainly works well for massive amounts of points/line segments. There is no reason why this simple approach cannot work for you as well.
I'm designing a simple Cocoa app. This is basically my second Cocoa app (despite being good at CocoaTouch), so I'm looking for an in-depth pros/cons analysis of 2 possible solutions for a window flipping problem.
What I'm trying to make is an utility app that sits in the menu bar and has its preferences o its “flip” side, Dashboard-style. It would flip from http://cl.ly/1G2M3J2c142Z0V3K0R2e to http://cl.ly/021z2v2h232x310z1g2q and back.
There are multiple questions on SO about the implementation of this effect:
Core Animation window flip effect
Widget "flip" behavior in Core Animation/Cocoa
Flipping a Window in Cocoa
I've looked at the example code there. Besides neither of them being as smooth as Dashboard widgets (but I'm yet to get to “making it smooth” part), they also share another trait -- they all flip between two different windows.
Now, coming from iOS, the way I started implementing it is to have a single window, but swap between two NSViews.
So what are the pros and cons of these two approaches, and why did multiple unrelated Cocoa developers pick the first one?
Have two NSWindow's, and flip between them (hiding one and showing the other halfway through the flip).
Have a single NSWindow, but two NSView's, and switch the views halfway through the flip.
Is it more convenient to have things separated into different windows in Cocoa? Is it because you can use NSWindowController to manage their lifecycle? Are people just used to using windows because pre-Core Animation you couldn't give views a CA layer? Any other reason/convenience I am missing?
To the future generations: I believe people did it this way because they often flip between windows with different sizes, and then it's just less hassle to have them separate.
Also if you are looking for a good implementation, these guys nailed it: https://github.com/mizage/Flip-Animation
Hi i'm thinking about making midi step sequencer and I need to make a note grid/matrix that resizes/ adapts when you zoom. I've been searching for different ways of doing this but cant figure out a way that works well.
I thought about drawing cell objects made with (NSRect) but I couldn't figure out how to get the right interaction when resizing.
This is my first "biggish" OBJ-c project so please don't kill me, im still battling with the frameworks and the syntax is so foreign to me.
You could use Core Animation layers to create your grid.
Take a look at Apple's Geek Game Board sample code project:
http://developer.apple.com/library/mac/#samplecode/GeekGameBoard/Introduction/Intro.html
The code shows a way to display different kinds of card/board games using CALayer.
The Checkers game looks to be the closest to the grid you want to create.