I have UIView with UIImageViews, UILabels, UITextView.
My goal is to transform the middle part so it would look like folding a piece of paper:
- top and bottom parts remain the same only they slide towards eachother
- middle part folds towards the screen
(as in Clear app: http://blog.massivehealth.com/post/18563684407/clear?cbe4fc38)
My idea was to first load whole view, then split into 4 parts, make middle two parts into CGImage and somehow animate them with perspective while simultaneously transforming top and bottom parts, so they slide towards eachother (in the end, middle two parts should become invisible).
I also should be able to unfold this view and scroll UITextView.
I'm not looking for a ready-to-go answer, just pointers towards correct solution.
I have came across CALayer, CABasicAnimation and CGImage, but yet don't know how to solve this one.
I think your approach is sound. Since you cannot apply a transform to part of a view, you have to split your container view into separate parts. You can use the CALayer method renderInContext: to render a view into a static image. You can then split this image into the parts you need, place the image parts over the original view (or replace the view with the image) and animate the images. When the animation has finished, reinstate the view in its new form.
A few pointers:
convert your UIView into an image: see this post; either you take 4 "snapshots" of your view, or:
1.2 you take one, then crop the resulting image (see here for cropping);
create a new view and add 4 CALayers as sublayers of self.layer; each layer has its contents property set to the corresponding UIImage;
animate the view layers as you need; have a look at this file from the Leaves framework to see how this could be done; basically, this code uses a CATransaction and transformations to animate a property of the layers (which in this case represents the position of one layer respect another), so that when that property value changes, the layers are redrawn accordingly.
Hope it helps.
Related
I wanted to create a progress bar as shown in the image:
I used the code mentioned in this blog
but I am unable to add separators and reduce the space between them.
I have managed to do like this through storyboard:
How can I change the code or is there any easier way to create?
You didn't specify what sort of animation you want on your progress indicator, but certainly achieving the drawing you've shown in your first screenshot shouldn't be any problem; I was able to throw this together in a couple of minutes:
Each thing in that drawing (other than the face) is a CAShapeLayer: the dark background circle a shape layer, the animated green circle in front of it is a shape layer, and each of the eight little lines that indicate the segments is a shape layer. So I have ten shape layers in total. They are added in that order, so that the little lines appear in front of everything else.
If the goal is to "fill" each segment in discrete steps, rather than a smooth animation through all values, that's a trivial modification of what I've already described.
Summary, in iOS how to have a view that modifies the pixels of all the views behind it.
Say you have a view, well any views, but let's consider a collection view which happens to just be some color blocks:
Say we added a view on top, CleverView, which either just blocks that view (so, white - trivial) or even "cuts a hole" in that layer (relatively easy to do, google).
No problem so far: so here's CleverView just a white square:
But what if we want to do this:
CleverView is changing all the saturation below it,
Or perhaps this:
CleverView is changing the hue or whatever below it.
Note that in the examples it's working in a pixel-wise fashion, it's not ("just") flagging each collection view cell to change all of the cell color.
So ideally CleverView would do this to anything at all that happens to be behind it (ie, whatever bunch of views it covers or partly covers, hence the collection view example which is just 'many views).
Naturally both the underneath stuff, and the shape of CleverView, can be animating, moving, in real time.
Is there a way this could be done in iOS?
(In that specific example, what I do is just, have two of the collection views: the bottom one and the top one has the new color values. Simply with care clip the top one to achieve the effect. But obviously that's not as Clever as a view that actually "modifies the values of all the pixels behind it".)
{Note too that, obviously, you can just make basically a screen shot, munge that image, and show it; not really a great solution.}
The CALayer has a property backgroundFilters where you could normally add a CIFilter that would do the job. But, documentation states that
Special Considerations This property is not supported on layers in
iOS.
That's annoying, but that's all that we have. Probably, it's due to performance considerations.
I would suggest to look into SceneKit, there the primitives are very similar to CoreAnimation, also animatable with CAAnimation, but provide advanced tools to configure and control many more aspects of the rendering.
For example, SCNNode has filters: https://developer.apple.com/documentation/scenekit/scnnode/1407949-filters?language=objc
I need to create an animated chevron effect using the bitmap tile below. I am hoping that a UIView with a pattern fill will be sufficient, but I need to be able to animate the origin of the pattern over time, and I can't see that this is possible.
I think this is possible with Quartz, or CoreGraphics at the low level. What would be the best way to do this, and can you provide some example code in Swift that demonstrates the solution?
I would add the image as contents of multiple sublayers (CALayer instances) aligned one below the other and animate those sublayers y position.
The main layer would clip its sublayers on the border and sublayers that go offscreen would move to the bottom to be reused, similarly to how UITableView reuses its cells.
You might also want to look at CADisplayLink to have better control of the rendering.
i have a subclass of UIView that displays own content. I'd like to animate the content.
The content is self-drawn in an own drawRect:, i wonder what possibilities are there to animate it. The content itself consists of graphical shapes that change their form.
I don't see a way to construct the content with subviews that can then be animated themselves.
Is there a way to use an UIView animation block?
Are there other possibilities? I would not want to animate this using OpenGL ES, this would be my last choice.
Thanks for any hints
Torsten
are you sure you can't use CALayer? They are made for this! You can create complex frames/textures (you wrote you have geometric shapes) and apply animated transforms to them.
Consider that if your shapes don't fit in the (really wide array of possibility) of shapes, you can basically draw any line using a CALayer: you create a layer of the proper length and width then simply translate and rotate it as needed (and of course translation an rotation are "animatable").
I have multiple views with many UILabels on the views. (all constructed in Interface Builder).
I am then trying to create a "smaller" replica of my view when you pinch the screen.
To do this I apply:
view.transform = CGAffineTransformMakeScale(.5, .5);
and then I also adjust the frame of view.
The problem is that after the transformation, the text in all of my UILabels becomes "blurry". It doesn't stay pixel perfect as it is in full-scale view.
Is there a way to increase the pixelation of the labels after the transformation?
Applying a transform to a UIView or CALayer merely scales the rasterized bitmap of that layer or view. This can lead to blurriness of the resulting UI element, because they aren't re-rendered at that new scale.
If you really want your text or images to be crisp at the new scale factor, you're going to need to manually resize them and cause them to redraw instead of applying a transform. I described one way that I did this with a UIView hosted in a UIScrollView in this answer.
You might be able to create a single method that traverses your view hierarchy for your one main view, recursively reads each subview's frame, scales that down, and then forces a redraw of its contents. Transforms are still great to use for interactive manipulation or animation, but you can then trigger a full manual scaling and redraw at the end of the manipulation or animation.