core-animation

问题 I'm trying to make a sequence of animations, I've found in CAAnimationGroup the right class to achieve that object. In practice I'm adding on a view different subviews and I'd like to animate their entry with a bounce effect, the fact is that I want to see their animations happening right after the previous has finished. I know that I can set the delegate, but I thought that the CAAnimationGroup was the right choice. Later I discovered that the group animation can belong only to one layer,

问题 I can add a border to a CALayer in this way: [webView.layer setBorderColor: [[UIColor colorWithRed:0.6 green:0.7 blue:0.2 alpha:1] CGColor]]; [webView.layer setBorderWidth: 2.75]; But is it possible to add a border only at one side? I only need a border at the bottom. Or can I reach this with other properties, e.g. frame, bounds, mask, ...? Thanks for your help! @Control-V UIWebView *webView = [[UIWebView alloc] init]; CALayer *webViewLayer = webView.layer; // now you can do a lot of stuff

问题 I can add a border to a CALayer in this way: [webView.layer setBorderColor: [[UIColor colorWithRed:0.6 green:0.7 blue:0.2 alpha:1] CGColor]]; [webView.layer setBorderWidth: 2.75]; But is it possible to add a border only at one side? I only need a border at the bottom. Or can I reach this with other properties, e.g. frame, bounds, mask, ...? Thanks for your help! @Control-V UIWebView *webView = [[UIWebView alloc] init]; CALayer *webViewLayer = webView.layer; // now you can do a lot of stuff

问题 I have an app that's half way done. The performance is not really good, and I wonder where the bottlenecks are. Although I can go ahead and start commenting out suspected lines of code, I wonder if there are any tools that would tell me which method cool took how long and what happened next. The stack trace isn't really that helpful. I had a weird idea to convert the stack trace into an GraphViz graph, to see visually the whole picture. I know some guys at IBM did something similar that

问题 i had tried various method and couldn't figure out how to achieve this.i searched on internet a lot but can't figure out. i have an ImageView (a wheel which spins) , i want to rotate it by 360 degree for 10 times(this is to just give user feel of fast turning wheel) , and then i want to rotate it by particular value say 90 degree( but it might be varying). after this animation finishes i want to bring ImageView back to the initial position. how do i achieve this ? Thanks in advance. 回答1: well

问题 i had tried various method and couldn't figure out how to achieve this.i searched on internet a lot but can't figure out. i have an ImageView (a wheel which spins) , i want to rotate it by 360 degree for 10 times(this is to just give user feel of fast turning wheel) , and then i want to rotate it by particular value say 90 degree( but it might be varying). after this animation finishes i want to bring ImageView back to the initial position. how do i achieve this ? Thanks in advance. 回答1: well

问题 In my code I create a CAKeyframeanimation with an infinite repeat count, add it to a specific CALayer. I would like to modify the duration (= the speed) of the animation while animating, without the need of restarting my animation. So when i click on a button, i get a duration that I can set for the animation. I have to remove the animation, create another one, and make it start to where i stopped it. The problem is that I can't seem to restart it from that point without making it loop from

问题 I am trying to create a fairly simple animation using 6 CALayer objects, each masked by a path. However, I am running into significant lag spikes when trying to animate them. Here is a video of the animation running. I am able to boost performance by setting shouldRasterize to YES , however it results in pixelation of the text, as you can see from this image: I can correct the pixelation by setting the rasterizationScale to the screen scale, however that brings back the lag spikes that

问题 I want to know how can I animate a change in the alignment property of an horizontal UIStackView say from UIStackViewAlignmentCenter to UIStackViewAlignmentTop and vice versa, and I want to visually reflects this change at the same time. EDIT: What I have: This is my hierarchy of views: two buttons named b1 and b2; b1 has an action named "changeAlignmentToTop" and b2 has an action named "changeAlignmentToCenter", which are activated Upon touch Up Inside in the respective button. an UIView

问题 I am playing a movie using an AVPlayer and animating 500 falling particles on top. I tried to simply add 500 animated CALAyers. I tried several variations on that but performance is always a problem. As soon as I get more then around 100 CALayers, the video gets choppy. What would be the proper way to do this? I thought maybe this should be done using OpenGL, but I never used it and can't find how to have a video played in OpenGL. I can get the background videos as separate frame pngs, but