Image processing - How detect array similar colors from a image on ios - objective-c

I want to create a area of similar colors when user touches into a point on imageview. Who knows library or technique to resolve problems for ios.
Original image link:
http://cannshine.com/images/1.jpg
After touched by user, link:
http://cannshine.com/images/2.jpg
Please helping, thanks!

It looks to me like you want to create a magic wand tool, correct? I can't help you come up with a way to handle this and I don't know of any libraries that can select a group of like-colored pixels based on tolerance, but there is this article here I found. It covers implementing a magic wand tool using Objective-C. I found it in the answer to this similar question on SO.

Related

How to achieve this image distortion effect in iOS?

I'm building an iphone photo app. I don't know how to achieve this kind of effect on an image:
When the user drags a finger across the arrow, I want the image to be distorted accordingly. How can I achieve this? Is there any framework that makes this process simple?
Thank you.
No clue about iOS, but the look reminds me of a thin-plate spline warp. It's quite easy to implement in OpenGL, a quick Google search for example code returns plenty of hits.
From the sound of it I think your looking for the CoreImage framework. Look into the various distortion effects...in particular CIBumpDistortionLinear.
I don't have any code so check out this tutorial and read up on CoreImage.

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I'm trying to create a custom NSTextFieldCell for a NSTableView. I want to do something like the email listing provided by Mail (example below).
I found some references here and here, but I'm not able to evolve.
I think that it's not as simple as a multiline text. I think the cell should have predefined places, like the timestamp on the upper right corner, the attchment icon, etc... This "placeholders" should be always at the same place, regardless the text size. I'm thinking about embeeded objects.
Please, could you help me? An example or sample code is very welcome.
EDIT: I'm looking for a MAC OS X Lion (10.7.x) solution.
Based on Monolo comment, I googled view-based table view. I found this excellent tutorial and followed it and I succeeded.
I also found this OS X Developer Library document regarding view-based programming guide. Very good too.

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I'm following this guide: http://www.aishack.in/2010/08/sudoku-grabber-with-opencv/2/
and modifying to iOS 5.0.
I managed to find the largest contour (the sudoku "board"), however, it only locates the surrounding square, without the lines inside, as in the tutorial. can this be easily solved?
I'll try and find a way around it, but still would like to know. thanks!
I assume that you are using the camera right now. Try to load the image what is used in the tutorial and check if your implementation works on that image. Then you can continue with nice sudoku images from the web. You may also change the camera angle and distance from the sudoku when taking pictures to get a better, clearer view.

iOS: compare a slice of an image to library of options

I'm basically trying to work out how to take a slice of an image, say a screenshot of an iPhone home screen, slice out the first icon and compare it to a set array of images in a library. Any help on where to start?
I'm no iPhone programmer, but I might be able to suggest a few things:
The SURF feature detection implemented in OpenCV should help you with this
There is a nice article on using OpenCV in Objective-C code.
A quick & dirty way might be to use the difference blend mode which should return the difference between the 1st image(top) and the 2nd image(bottom). If there is no difference the result will be completely black. So, the more black pixels in the difference result, potentially, the more similarities between the compared images.
I'm not an iOS developer, so I don't know if there is an image library that ships with sdk or if there's a free/opensource library for basic image processing. Still this should be trivial to implement:
e.g.
- (int)difference((int)topPixel,(int)bottomPixel)
{
return abs(topPixel-bottomPixel);
}
Note: Syntax might not be correct :)
HTH
This may not help you with taking a screenshot of the iOS home screen... But these articles show how to take snapshots from within a UIKit application:
https://developer.apple.com/library/prerelease/ios/#qa/qa1703/_index.html
https://developer.apple.com/library/prerelease/ios/#qa/qa1714/_index.html
Perhaps you would instruct the user to press home-power (buttons) to take a snapshot and store in the photo roll, then load that screenshot into an app to process the screenshot.
Hope this helps!

Library for displaying image sets on an iPad

I'm looking for some cool libraries out there to display a bunch of images in my iPad application.
I think they are already out there, and I don't have to start from scratch, but I can't find some good ones.
Check out AQGridView as well.
Check out KTPhotoBrowser, I use it in a universal app, and it works pretty good.
Also, search Github : Photo Gallery for more open-source solutions.
See the answers to these questions on Stack Overflow:
How To Create A Gallery on iOS
float:left in objective-c
There are probably more questions about the same subject. Seek and you shall find.
I would simply create a web page with all the images, and then display it using UIWebView.
Did you want to do the coding yourself?
I found the Apple example "LazyTableImages" to be a useful and elegant way to display many images in a table view. It's important to a) keep the scrolling nice and smooth, and b) not freeze the user interface while downloading.
Have you tried using a UIImageView?