I've got a UIImageView that takes up the whole cell and shows an image. I'd like to blur the bottom third of the view in the iOS7 style (we're targeting iOS7). There will be a label over the blurred part.
The issue seems to be that I can't "screenshot" the UIImageView right as I am setting up the cell in tableView:cellForRowAtIndexPath: as it hasn't loaded yet. Although i've even tried setting up a timer for a 0.1 second delay and that also doesn't work.
I've tried the stuff on http://damir.me/posts/ios7-blurring-techniques
I've tried https://github.com/justinmfischer/7blur
I'd like to use the new screenshotting API drawViewHierarchyInRect:afterScreenUpdates:
I'd also like to use apple's sample code UIImage+ImageEffects
The only thing that has worked so far has been to just put a UIToolbar in but the performance is really slow. I don't need dynamic updates.
I've managed to get the following effect a few times but it has just tinted the view and hasn't actually blurred anything so I'm a bit confused.
Use UIImageEffects sample from apple
Make a Image View with a size of the lower portion you want to blur... and then set its image to a blurred one. also set its content mode to UIViewContentModeBottom for the proper clipping
Since your image isnt the size of the cell.. first get a temp image as it is being displayed in the cell by drawing a UIImage from it.. refer for the code here
How to capture UIView to UIImage without loss of quality on retina display
then blur that image
Load this image into a UIImage, blur the image, clip to fit the area that you want. Use UIImage+blur.h
Related
I am trying to tile an image for an app I am making. I am making rope that I can set the length for. In order to do this, I have a function that takes my rope length, sets the frame size accordingly, and then sets the background color like this:
(picture is a UIView)
picture.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"Rope.png"]];
The view is blank. I tested it before by displaying an image by making picture a UIImageView instead, and it worked, but it won't show up anymore.
EDIT: I have now tried a few different methods of tiling, the best I can get is a stretched image. I need a working way to tile an image and get the output of my tiled image into a UIImage, UIImageView, or UIView.
Not sure what I did wrong but it is working now.
I got a UIView subclass that draws a UIImage as its background. The image is created using the stretchableImageWithLeftCapWidth:topCapHeight: method, it has round edges.
I also use an animation block inside of which I resize my view. I had hoped that during animation, the drawRect:method would get called sometimes, which would result in the background image getting drawn correctly.
Unfortunately, the animation seems to render the image and then just rescale it during the animation, which obviously makes the formerly round edges getting nastily stretched.
The only workaround I can imagine is put three separate UIImageViews (top cap, middle fill, bottom cap) above my original background image and then reposition the caps images and scaling the fill image. However, this seems quite complicated...
Is there any better way I can prevent this from happening?
EDIT: Found this. Sounds bad...
While digging through some Apple docs, I coincidentally found the solution to my problem. All you have to do is play with UIView's contentStretch parameter. It allows you to manually specify the area of your view that gets stretched during animation.
Hey I just had a simple question about implementing landscape mode for an app, particularly running on the iPad (but I am sure the concept holds true for the iPhone). I have a custom background image that I am wanting to use for my root view. I designed the image so that it fits the iPad screen size for portrait mode. Do I need to design a second image for landscape mode so that it fits correctly? Is that how the landscape/portrait transition works, switching between two different images? I really don't have any idea, so any help would be appreciated. Thanks!
One other thing to think about is that the UIImage class has stretchableImageWithLeftCapWidth:topCapHeight: method to take an existing image, and build a new image that can adjust to any size by repeating only the central portion of the image and leaving the corners of the image as fixed image segments.
You can load in a fixed UIImage, generate a stretchable copy using this method, and assign it to a UIImageView - then as you resize the UIImageView due to rotation, the image will adjust as needed and not resample the image.
Assuming you have a UIImageView as your backdrop, change its image property after the device orientation changes.
See Handling View Rotations in http://developer.apple.com/iphone/library/documentation/UIKit/Reference/UIViewController_Class/Reference/Reference.html
All,
I'm having trouble getting behavior that I want from CATiledLayer. Is there a way that I can trigger the tiles to redraw without having the side-effect that their areas are cleared to white first? I've already subclassed CATiledLayer to set fadeDuration to return 0.
To be more specific, here are the details of what I'm seeing and what I'm trying to achieve:
I have a UIScrollView with a big content size...~12000x800. Its content view is a UIView backed by a CATiledLayer.
The UIView is rendered with a lot of custom-drawn lines
Everything works fine, but the contents of the UIView sometimes change. When that happens, I'd like to redraw the tiles as seamlessly as possible. When I use setNeedsDisplay on the view, the tiles redraw but they are first cleared to white and there's a fraction-of-a-second delay before the new content is drawn. I've already subclassed CATiledLayer so that fadeDuration is set to 0.
The behavior that I want seems like it should be possible...when you zoom in on the scrollview and the content gets redrawn at a higher resolution, there's no blanking before the redraw; the new content is drawn right on top of the old one. That's what I'm looking for.
Thanks; I appreciate your ideas.
Update:
Just to follow up - I realized that the tiles weren't being cleared to white before the redraw, they're being taken out entirely; the white that I was seeing is the color of the view that's beneath my CATiledLayer-backed view.
As a quick hack/fix, I put a UIImageView beneath the UIScrollView, and before triggering a redraw of the CATiledLayer-backed view I render its visible section into the UIImageView and let it show. This smooths out the redraw significantly.
If anyone has a better solution, like keeping the redraw-targeted tiles from going away before being redrawn in the first place, I'd still love to hear it.
I've found that if you set levelsOfDetailBias and levelsOfDetail both to the same value (2 in my case), then it only redraws the tiles that are touched by my setNeedsDisplayInRect: call, as you'd hope.
However if the levelsOfDetail is different to LODB, then any calls to setNeedsDisplayInRect: redraw all the tiles.
You could add another layer (possibly a CATiledLayer) behind the existing tiled layer. (Sort of a double-buffered solution.) You would call setNeedsDisplay: on the second layer from a timer that fires after a few seconds to ensure that that layer doesn't redraw at the same time as the front layer.
Another potential option is to use the same delegate to draw content to a bitmap context and swap the bitmap into the backing store once the content is refreshed. This should produce a flicker-free result. That being said, I can't tell you how this might be done, and one nice thing about CATiledLayers is they automatically generate tiles when you zoom and pregenerate tiles when you pan once zoomed in.
I would like to see how you implement your application. I have been looking for weeks to find an example that uses a combination of UIScrollView and a CATiledLayer-back view with a lot of custom drawn lines. Apple has some great sample code - but it all involves images rather than line art, so no help for me.
Having read through these answers without a solution, I discovered that tiling a page was the dominant background task.
Preparing my lo-res placeholder image on a high priority queue solved this issue - the images now appear while the tiling is occurring. Caching the placeholder images further improves their appearance - they appear before the tiling begins.
With newer devices, the tiling it so fast, these tricks might not matter. A sample PDF consisting of large scanned images (e.g. a scanned book) tiles the slowest in my experience, and makes for good test data.
I had the same problem with iPad.
The solution was more simple than I thought and far more simple than using UIImageView to render display before redrawing... :
Just don't set any background color for the Layer!
I had CATiledLayer set in a similar way:
layer = [[CATiledLayer alloc] init];
layer.masksToBounds = YES;
layer.contentsGravity = kCAGravityLeft;
//layer.backgroundColor = [[UIColor whiteColor] CGColor];
layer.tileSize = CGSizeMake(1004.0, 1004.0);
layer.levelsOfDetail = 16;
layer.levelsOfDetailBias = 8;
Note that I have commented out the line setting layer's background color to white.
After that the white blank before redraw problem disappeared!
Let me know if anyone has tried that.
I have a custom UIImageView class which I use to handle multi-touch events on the UIImageView. When the user touch begins, I want to increase the UIImageView's frame but keep the UIImage size fixed.
I tried changing the UIImageView's frame and then calling the drawInRect: method of UIImage to keep the UIImage's size fixed. But this is not working.
The contentMode for the UIImageView is set as ScaleAspectFit and as soon as I increase the frame size of the UIImageView, the UIImage size also increases (and is not affected by the drawInRect:)
Can someone please tell me how I can achieve this?
Thanks.
Adding more details
What I am trying to do is this
Place a UIImageView on the screen with the size same as the size of the image
When the user selects the image, anywhere he touches, the image edits as if the user is doing multi-touch with the image
If I increase the size of the imageview to detect touches any where, the image size also increases... Hope that makes things clearer!
Thanks
There may well be other ways to do it, but I think the UIImageView is doing what it's intended to do here.
What do you want the area of the view not covered by the image to look like? Be transparent? Have a solid colour?
Why do you want to do this? Is it to capture touch events from a wider area than that under the image itself?
If you have a good reason for needing to do this I would create a new view, probably just a plain UIView (with background set to transparent colour), and add the UIImageView to that. Make the plain view the one you resize.
I haven't specifically tried this, but I think it would work:
imageView.contentMode = UIViewContentModeCenter;