ios - How to get the current animation step from a CAKeyframeAnimation -


i'm creating small button 2 different states. every state represented 2 cashapelayers , transition between states animated series of cakeyframeanimations/cabasicanimations, change path property of shape layers. question how animate state starting current animation (i.e. button pressed while animating).

normally, ask presentation layer current property value , use additive animation (as described here), since multi-step animation have figure out step animating , chain appropriate animation reverse previous state. rather tricky (i wanted have animation removeoncompletion=false , query time offset of animations figure out animation active , how far).

unfortunately, setting layer speed 0.0 , animating timeoffset , forth doesn't work either, since have secondary animations behave differently in opposite direction.

using custom layer property shape layers seems cumbersome, match progress property more current animation step.

so after trial , error come following "solution": use cadisplaylink time update every frame , subtracting current timestamp timestamp when animation started, can figure out elapsed animation time, progress (by dividing through animationduration). way can start reverse animation offset. internally, calculate next frame keyframe animation , adjust keytimes new duration. can see implementation of here


-

Popular posts from this blog

php - How should I create my API for mobile applications (Needs Authentication) -

background so i've been researching quite bit past week api's , have been reading concepts , programming one. currently have website programmed in php using popular framework called laravel. website has user database , users able log dashboard on website, works want website side. now next project of business i'm focusing on creating mobile applications (ios & andriod).what need these mobile applications being able login through application ui (not being redirected site callback url) able view , manage dashboard. the method of authentication , authorization want use application go like client asks user login through ui user enters credentials client sends request login api the api checks if credentials correct api creates token stored in token database linked user id api returns 200 ok json response or this { "token" : "ols25usjiay81hdy81", "expiry" : 3/06/2016 14:00} client remembers token , expiry whenever user/c...
Read more

python 3.x - PyQt5 - Signal : pyqtSignal no method connect -

following example in doc found on sourceforge faced error. from pyqt5.qtcore import pyqtsignal, pyqtslot def setsignal(): signal = pyqtsignal() signal.connect(self.myaction) @qtcore.pyqtslot() def myaction(): print("signal triggered") results in attributeerror: 'pyqt5.qtcore.pyqtsignal' object has no attribute 'connect' as mentioned in docs linked, signal needs defined on class level: class foo(qobject): signal = pyqtsignal() def connectsignal(): self.signal.connect(self.myaction) @qtcore.pyqtslot() def myaction(): print("signal triggered")
Read more

5 Reasons to Blog Anonymously (and 5 Reasons Not To)

Image
This guest post is by Phil (not his real name) of somehighschoolblog . It used to be impossible to run a business anonymously. Sure, some authors could pull it off, but if you worked at an office, what were you supposed to do? Go to work with a bag over your head? But today anyone can accomplish this, because anyone can author a blog (and you thought I was going to tell you to work with a mask on, or something). Copyright Ovidiu Iordachi - Fotolia.com Depending on your motives, you may or may not have considered blogging anonymously. You probably didn’t contemplate blogging anonymously if: • your only motivation is to become “famous” • your blog connects to another part of your life • you are blogging to build more connections with your friends or boss. You should consider blogging anonymously if: • you’re planning on touching on a sensitive or taboo subject • you don’t want to be identified with your blog • you are worried about negative real-world consequences that could arise from y...
Read more