Instagram Image Filters on iPhone

Question

How does one go about adding image filters in an iPhone application? (similar to what Instagram and picplz have)

Answer 1

I think you can also port, most of the C code, from free image processing libraries. And then use pixel based modifications.

Answer 2

Have you checked simple-iphone-image-processing? It is a “simple C++ class with an Objective-C wrapper that provides a set of common image processing tasks” as well as UIImage conversion. It provides:

• Canny edge detection
• Histogram equalisation
• Skeletonisation
• Thresholding, adaptive and global
• Gaussian blur (used as a preprocessing step for canny edge detection)
• Brightness normalisation
• Connected region extraction
• Resizing – using interpolation

Other C++ open source libraries are:

1. http://cimg.sourceforge.net/
2. http://filters.sourceforge.net/

Edit Also, take a look at this open-source code - https://github.com/OmidH/Filtrr

Answer 3

Folks,

I have made an attempt at replicating instagram and photoshop filters using pure CoreGraphics and direct pixel manipulation, not using OpenGL.

Find this project at:

https://github.com/esilverberg/ios-image-filters

** UPDATE **

You also should consider this project: https://github.com/gobackspaces/DLCImagePickerController

Answer 4

Sadly there is no CoreImage library in the iOS SDK so you have to use OpenGLES to do image processing, Apple have an example application that demonstrates several techniques.

http://developer.apple.com/library/ios/#samplecode/GLImageProcessing/Introduction/Intro.html