While debugging the View Hierarchy, I came across this optimization warning about a UISwitch control with a mask view. Though I have no clear picture what would be the benefits of addressing this warning (insights please), I tried to fix it with no success.
Optimization Opportunities: The layer is using a simple layer with background color set as a mask. Instead, use a container layer of the same frame and cornerRadius as the mask, but with masksToBounds set to YES.
let maskedSwitch: UISwitch = UISwitch()
maskedSwitch.translatesAutoresizingMaskIntoConstraints = false
maskedSwitch.tintColor = .black
maskedSwitch.onTintColor = .green
maskedSwitch.backgroundColor = .black
let maskView = UIView(frame: maskedSwitch.frame)
maskView.backgroundColor = .black
maskView.layer.cornerRadius = maskedSwitch.frame.height / 2
maskView.layer.masksToBounds = true
maskView.clipsToBounds = true
maskedSwitch.mask = maskView
let scale: CGFloat = 2.5 / 3
maskedSwitch.transform = CGAffineTransform(scaleX: scale, y: scale)
As suggested, I tried removing the maskView and directly applying the cornerRadius and offTintColor on switch. But it ended up messing the scale transformation, and it is kind of important to retain the UI.
How can I further optimise the code and make sure all these conditions addressed: 1. set offTintColor to black, 2. scale the switch and 3. Avoid the optimization opportunity warning?
Note: Please do share if there is an Apple doc to study more on the topic Optimization Opportunities. Thanks!
Related
I need to create a component that will let users choose from 2 choices in images. At first, you see 2 images side by side with a "handle" in the middle. If you move the handle to the left, you will see more of the image to right and less of the left image, as to reveal the right image, and vice versa.
Technically, I have 2 full size UIImageViews one on top of the other, and they are masked. I have a pan gesture and when the user slides the handle, the handle moves and the masks update themselves to adjust to "the new middle".
Here's the code responsible for adjusting the image mask. The constant is calculated in the method called by the gesture. I know my calculations of that constant are good because the "handle" and the masks are updated correctly.
BUT
the masks gets updated too late and when dragging, we see it being adjusted too late.
func adjustImagesMasks(to constant: CGFloat) {
choiceImageA.mask?.willChangeValue(forKey: "frame")
choiceImageB.mask?.willChangeValue(forKey: "frame")
let separationPoint: CGFloat = self.frame.width / 2.0 + constant
maskA.backgroundColor = UIColor.black.cgColor
maskA.frame = CGRect(origin: .zero, size: CGSize(width: separationPoint, height: self.frame.size.height))
maskB.backgroundColor = UIColor.black.cgColor
maskB.frame = CGRect(x: separationPoint, y: 0, width: self.frame.width - separationPoint, height: self.frame.size.height)
choiceImageA.mask?.didChangeValue(forKey: "frame")
choiceImageB.mask?.didChangeValue(forKey: "frame")
maskA.drawsAsynchronously = true
maskB.drawsAsynchronously = true
self.setNeedsDisplay()
maskA.setNeedsDisplay()
maskA.displayIfNeeded()
maskB.setNeedsDisplay()
maskB.displayIfNeeded()
}
The image views have their masks setup like this:
maskA = CALayer()
maskB = CALayer()
choiceImageA.layer.mask = maskA
choiceImageA.layer.masksToBounds = true
choiceImageB.layer.mask = maskB
choiceImageB.layer.masksToBounds = true
So to recap, my question is really about performance. The image views are being correctly adjusted, but too slowly. The "handle", which is positioned with constraints, get updated really quickly.
So apparently, CALayer tries to animate most of the changes to its properties. So the delay I was seeing was in fact due to an animation.
I resolved my issue by surrounding the call to adjustImagesMasks() with CATransaction.setValue(kCFBooleanTrue, forKey:kCATransactionDisableActions) and CATransaction.commit(). So for this transaction, I'm asking to not animate the changes. Because this is continuous (with the panning gesture), it is seemless.
Full code here:
CATransaction.setValue(kCFBooleanTrue, forKey:kCATransactionDisableActions)
adjustImagesMasks(to: newConstant)
CATransaction.commit()```.
This other post helped me a lot. There's a nice explanation too.
Hope this helps someone else.
I add one node and try to setting shadow blur with SceneKit
here's my light config, I did try to set shadowRadius
light = [SCNLight light];
light.type = SCNLightTypeDirectional;
light.castsShadow = true;
light.shadowMode = SCNShadowModeForward;
light.shadowRadius = 5;
light.shadowMapSize=CGSizeMake(4000, 4000);
light.orthographicScale=25;
light.zNear=1;
light.zFar=1000;
but the result is not softer than when I not set shadowRadius
it' here:
I did try to add samplecount
light = [SCNLight light];
light.type = SCNLightTypeDirectional;
light.castsShadow = true;
light.shadowMode = SCNShadowModeForward;
light.shadowRadius = 5;
// add samplecount
light.shadowSampleCount = 5;
light.shadowMapSize=CGSizeMake(4000, 4000);
light.orthographicScale=25;
light.zNear=1;
light.zFar=1000;
result look like following
shadow seem soft but this shadow start from bottom of the node (z coordinate is 0). I spend a lot of time to set soft shadow only in the edge of node, not from bottom. But no result.
This problem also occurred when add two node cross over(not only node and geometry as SCNFloor)
My problem is how to get shadow blur(soft shadow) with direction light.
any help would be appreciated!
Swift 4 / Xcode 9.2
I got a pretty good result with these settings:
light2.castsShadow = true
light2.automaticallyAdjustsShadowProjection = true
light2.maximumShadowDistance = 20.0
light2.orthographicScale = 1
light2.shadowMapSize = CGSize(width: 2048, height: 2048)
light2.shadowMode = .forward
light2.shadowSampleCount = 128
light2.shadowRadius = 3
light2.shadowBias = 32
Increasing the shadowRadius to 12 helped a lot with my model, but then I needed to increase shadowSampleCount and shadowBias to not get artifacts.
I really can make shadow blur with orthographicScale. I don't know why, but this trick work for me. Hope can help someone
light.shadowMapSize=CGSizeMake(4000, 4000);
light.orthographicScale=100; // bigger is softer
I also change shadowMapSize to bigger value and setting isJitteringEnabled antialiasingMode to reduce aliasing.
I'm sure this is a very simple thing to do, but I can't seem to wrap my head around the logic.
I have two UIViews. One black, semi-transparent and "full-screen" ("overlayView"), another one on top, smaller and resizeable ("cropView"). It's pretty much a crop-view setup, where I want to "dim" out the areas of an underlying image that are not being cropped.
My question is: How do I go about this? I'm sure my approach should be with CALayers and masks, but no matter what I try, I can't get behind the logic.
This is what I have right now:
This is what I would want it to look like:
How do I achieve this result in Swift?
Although you won't find a method such as subtract(...), you can easily build a screen with an overlay and a transparent cut with the following code:
Swift 4.2
private func addOverlayView() {
let overlayView = UIView(frame: self.bounds)
let targetMaskLayer = CAShapeLayer()
let squareSide = frame.width / 1.6
let squareSize = CGSize(width: squareSide, height: squareSide)
let squareOrigin = CGPoint(x: CGFloat(center.x) - (squareSide / 2),
y: CGFloat(center.y) - (squareSide / 2))
let square = UIBezierPath(roundedRect: CGRect(origin: squareOrigin, size: squareSize), cornerRadius: 16)
let path = UIBezierPath(rect: self.bounds)
path.append(square)
targetMaskLayer.path = path.cgPath
// Exclude intersected paths
targetMaskLayer.fillRule = CAShapeLayerFillRule.evenOdd
overlayView.layer.mask = targetMaskLayer
overlayView.clipsToBounds = true
overlayView.alpha = 0.6
overlayView.backgroundColor = UIColor.black
addSubview(overlayView)
}
Just call this method inside your custom view's constructor or inside your ViewController's viewDidLoad().
Walkthrough
First I create a raw overlayView, then a CAShapeLayer which I called "targetMaskLayer". The ultimate goal is to draw a square with the help of UIBezierPath inside that overlayView. After defining the square's dimensions, I set its cgPath as the targetMaskLayer's path.
Now comes an important part:
targetMaskLayer.fillRule = CAShapeLayerFillRule.evenOdd
Here I basically configure the fill rule to exclude the intersection.
Finally, I provide some styling to the overlayView and add it as a subview.
ps.: don't forget to import UIKit
There might be another drawing solution but basically you have 4 areas that need to be handled. Take the square area above and below the space with full width and add the right and left side between them with constraints to eachother.
I want to add shadows to views, each in a table view's content view, but as soon as I do the UI becomes incredibly unresponsive and laggy.
Does anyone know a better way to draw shadows than this:
mainView.layer.shadowColor = UIColor.blackColor().CGColor
mainView.layer.shadowOffset = CGSize(width: 0.5, height: 0.5)
mainView.layer.shadowOpacity = 0.3
mainView.clipsToBounds = false
mainView.layer.masksToBounds = false
mainView.layer.shadowRadius = 2
I'm looking to add multiple drop shadows with different opacities to a view. The specs for the shadows are as follows:
Y-offset of 4 with blur radius of 1
Y-offset of 10 with blur radius of 10
Y-offset of 2 with blur radius of 4
Blur radius of 1, spread of 1 (no offsets, will probably have to be 4 different shadows)
I can get all this working just fine using CALayers. Here's the code I have working for that (please note that I haven't bothered to set shadowPath yet, and won't until I get the multiple shadows thing working):
layer.cornerRadius = 4
layer.masksToBounds = false
layer.shouldRasterize = true
let layer2 = CALayer(layer: layer), layer3 = CALayer(layer: layer), layer4 = CALayer(layer: layer)
layer.shadowOffset = CGSizeMake(0, 4)
layer.shadowRadius = 1
layer2.shadowOffset = CGSizeMake(0, 10)
layer2.shadowRadius = 10
layer2.shadowColor = UIColor.blackColor().CGColor
layer2.shouldRasterize = true //Evidently not copied during initialization from self.layer
layer3.shadowOffset = CGSizeMake(0, 2)
layer3.shadowRadius = 4
layer3.shouldRasterize = true
layer4.shadowOffset = CGSizeMake(0, 1)
layer4.shadowRadius = 1
layer4.shadowOpacity = 0.1
layer4.shouldRasterize = true
layer.addSublayer(layer2)
layer.addSublayer(layer3)
layer.addSublayer(layer4)
(While this code is in Swift, I trust that it looks familiar enough to most Cocoa/Objective-C developers for it to make sense. Just know that layer is equivalent to self.layer in this context.)
The problem, however, arises when I attempt to use different opacities for each shadow. The shadowOpacity property of layer ends up being applied to all of its sublayers. This is a problem, as I need all of them to have their own shadow opacity. I have tried setting each layer's shadow opacity to its correct value (0.04, 0.12, etc.), but then the opacity of 0.04 of layer is applied to all sublayers. So I tried to set layer.shadowOpacity to 1.0, but this made all the shadows solid black. I also tried to be clever and do layer2.shadowColor = UIColor(red: 0, green: 0, blue: 0, alpha: 0.12).CGColor, but it was just changed to full black with no transparency.
I suppose it makes some sort of sense that the layers should all have the same shadow opacity. But what's a way to get this working, varying opacities and all (doesn't have to utilize CALayer if it's easier another way)?
Please don't answer with "just use an image": no matter how sane that may be, I'm trying to avoid it. Just humor me.
Thanks.
EDIT: As per request, here's what I'm after: .
The key thing that needs to be added is setting the layers' shadowPath. By default, Core Graphics draws a shadow around the layer's visible content, but in your code neither backgroundColor nor bounds are set for the layers, so the layers are actually empty.
Assuming you have a UIView subclass, you can make it work by adding something like this:
override func layoutSubviews() {
super.layoutSubviews()
layer.sublayers?.forEach { (sublayer) in
sublayer.shadowPath = UIBezierPath(rect: bounds).cgPath
}
}
I tested this approach on a view with multiple shadows and it worked as expected, as soon as the shadowPath is defined for the shadow layers. Different shadow colors and opacities worked as well, but you have to keep in mind that upper layers in the hierarchy will overlap the layers behind them, so if the front layer has a thick shadow, the other shadows can get hidden by it.
What about adding the alpha to the shadow color instead of the layer shadow opacity?
i.e. instead of
layer.shadowColor = UIColor.black.cgColor
layer.shadowOpacity = 0.5
do
layer.shadowColor = UIColor.black.withAlphaComponent(0.5).cgColor
for each layer.