Is there a way to clip objects in "letterbox" scaling mode? I can add black rectangles over the areas that I want to appear as clipped, but actual clipping should have a performance benefit. Is it possible?
No, there are no way to do actual manual culling.
On my company we also use black rectangles.
Corona culling, and there are no way to control it from our side, and it cull automatically everything outside the screen. In letterbox mode things in the "black" area of the letterbox are still inside the screen, thus they are not culled.
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I have a photoshop file with 8 concentric 'rings' (although some aren't rings and are more irregular), with the largest at the 'back' and decreasing in size up to the 8th one being very small in the centre.
The 'rings' are drawn in such a way as that the smaller ones are 'internal' to its 'outer' or next larger ring. Each 'ring' has transparency on its outside, but also on its inside (where the smaller rings would 'sit').
I need to support all iOS devices (Universal App).
The largest image has a default size of 2048x2048 pixels, but every one of the 8 layers has a common 'centre' point around which they need to rotate, and around which they need to be fixed.
So, basically, all 8 have to be layered, one on top of the other, such that their centres are all perfectly aligned.
BUT the size of the artwork is larger than any iOS device, and the auto-layout has to allow for every device size and orientation, with the largest (rear) layer having an 8 point inset from the screen edges.
For those that can't picture this, here is a crude representation, where the dark background is 'transparent' and represents the smaller of the width or height of the iOS device (depending on orientation):
Note: The placement of where each smaller UIImageView is precise. They all share a common centre (the centre of the screen) but each ring sits 'inside' of the larger ring behind it. i.e. the centre of the green, hot pink and baby pink circles are empty / transparent, and no matter what size screen or orientations, they have to nest together perfectly, as they do in the photoshop art assets.
I've spent hours in auto-layout trying to sort this out, and when I've got it working on one device and both orientations, it's not working on any others.
No code to show because I'm trying to do this in IB so I can preview on all devices.
Is this even possible using IB / Auto-Layout or do I have to switch to manually working out the scales by which to resize their UIImageView based on screen width / height at runtime and the relationship between each 'ring'?
Edit:
And unless I'm doing it wrong, embedding each UIImageView into a transparent UIView in order to use the UIView to fake 'insets', this doesn't work because those numbers are hard coded, such that when it's perfect on a 12.9" iPad Pro, on an iPhone SE each 'inset' UIImageView is much more compressed and doesn't sit 'inside' it's next larger ring, but is like a tiny letter O with lots of surrounding blank space, because those 'insets' don't scale. What is 100pts on an iPad is a tiny amount of space, but 100pts on an iPhone SE is a 1/3 of the screen.
You can draw circles using CAShapeLayer and UIBezierPath. Since you are trying to fit this in a square, I'd define container size to be either the width or height of the parent container depending on what's smaller, this will allow for rotation and different screen sizes. As for the center, you can always find it by getting center coordinates of your square container (container.bounds.size.width / 2). To rotate your layers/sublayers you can use this answer: https://stackoverflow.com/a/3929703/4577610
So here's my problem. I am currently trying to create a rectangular enclosure using four more rectangles as borders. So it would look somewhat like this. Keep in mind each side is individual so a rectangle with a border wouldn't work.
Now the actual problem comes with different screen sizes. Specifically the 4s. Since the screen is shorter than other phones, how would I resize the rectangles on the side to fit the height? One of my options was detect the screen size, and then set the height of the rectangle, but I was wondering if there was an easier way since I'd also have to deal with all the other screens.
Rather than hardcoding, you can get the maximum screen size with CGRectGetMaxX(self.frame), similarly there are CGRectGetMidX and CGRectGetMinX. With these three methods, you can set proportional height/width and coordinates for the rectangles.
got a question about turning pixels off on a screen. I can make a black image and show it full screen on my pc. Yet the screen looks black but the pixels aren't off. You can see the difference between an off screen and a black screen.
I am wordering if it would be possible to turn these pixels off via a program or is the best you can do: make them black?
I am looking for the delphi code to turn off the right half of my computer screen?
hope its clear!
thx
You can't turn off individual pixels, or parts of the screen. Either the screen is on or it's off.
This works a bit differently depending on what kind of screen it is, but nowadays LCD screens is the most common kind. An LCD screen has a backlight behind an LCD display; the backlight is always on, and shine through the LCD display when the crystals are transparent. Pixels are made black by making the crystals non-transparent, however they still let a fraction of the back light through. To make pixels completely black you would have to turn the backlight off, and you can only to that for the entire screen.
If I get it right, you want to turn off the power from the half of your monitor, what is impossible. It would have to be supported by your graphic card as well as by your monitor driver.
Turning off pixels can only work on new all-lead displays, except if you are switching off the computer, when all systems (including the screen) are off.
I'm using UIImagePickerController in a popover on the iPad to take a picture with the front camera. I set allowsEditing to YES and get the awesome built in "Move and Scale" view after taking the picture. The crop rectangle in this view measures 320x267 on the screen despite the fact that the image is cropped to a 320x320 square (http://dl.dropbox.com/u/2246698/moveAndScale.png). If i accept the image as is without resizing or moving it, there is a ~25px high black bar across the top as if the crop rectangle has been positioned too high on the image (http://dl.dropbox.com/u/2246698/cropped.png). In fact, if i get that crop rectangle from the media info dictionary (via UIImagePickerControllerCropRect) it shows that the y origin of the crop rectangle is at -39. This seems broken that the image would be incorrectly cropped by default and usually when it seems broken it's because i did it wrong. Has anyone ever seen this or know of some setting to twiddle that will be good for my crops?
Many thanks.
I see the exact same behavior. It MUST be a bug, but if it is, I don't know why more people aren't complaining about it. Another problem with it is that you can't move the picture to the edges to crop to include that part--it always slides back to the middle.
If you zoom it, then you can move it, but you can never move it far enough to be able to include the left or right edges.
The thing is next to useless.
I displays a splash Screen when my app loads,There is a background image in the splash screen,I problem is how can I make fit this image in all types of blackberry models?
Keep in mind that many BlackBerry devices have different screen resolutions and even different aspect ratios. So if you just use a single image and resize (stretch and/or squish) it to fit the current screen, you're going to distort the image (or pattern). As I see it, there are two main approaches:
1) Use a different image for each screen resolution. There are about 7 different resolutions that cover most of the in-market devices (240x260, 240x320, 320x240, 360x400, 360x480, 480x320, 480x360)
2) If it's a regular background pattern as opposed to a picture or logo, just have one image in the app that's big enough to cover the largest screen size (480x360) and for all other screen sizes just clip it. In fact, I think this should happen automatically if you just set the background image - anything that can't be displayed on the screen will be clipped.
While approach #2 is better in terms of reducing application size, I'm going to guess that since you're asking this question the background you're thinking of using isn't a regular pattern.
I think the simplest method would be to use the setBorder method of whatever screen/field needs a stretched background. For example:
Border b = BorderFactory.createBitmapBorder (new XYEdges (), bitmap);
field.setBorder(b);
In my experience this results in the background image being stretched and provides the simplest method for fitting the size you need. I have only ever used it for fields though and never a MainScreen so it might not work for you.