I was wondering, are there any libraries on the iPhone that allow you to take an image and apply some sort of filter to it so the image turns out black and white, or to make it look comicy, or to skew it?
Start by taking a look at CoreImage. Its available in iOS5. You'll probably want to explore third party options too.
Check out OpenCV. It's an open source library that can be compiled for iOS (there's plenty of tutorials all around the net) and it's specifically made for things like image manipulation.
While it's harder to set up, it's a lot more powerful than CoreImage will be!
There's also plenty of sample code around the net that does things like turn images comicy/black and white/find image outlines/thresholds images etc. There's a small learning curve, but for what you want to do, it's more than worth it :)
Related
Is there any filters available in ios to convert a image to cartoonistic image like exactly in the above picture?
For a much faster solution than ImageMagick, you could use the GPUImageToonFilter from my GPUImage framework:
It combines Sobel edge detection with posterization of the image to give a good cartoon-like feel. As implemented in this framework, it's fast enough to run on realtime video from the iPhone's camera, and is probably at least an order of magnitude faster than something similar in ImageMagick. My framework's also a little easier to integrate with an iOS project than ImageMagick.
If you want more of an abstract look to the image, the GPUImageKuwaharaFilter converts images into an oil painting style, as I show in this answer.
Try to use imagemagick for iOS http://www.imagemagick.org/download/iOS/
Of course you need some serval hours how to use imagemagick for iOS.
But then you should also look at: http://www.fmwconcepts.com/imagemagick/cartoon/index.php
and maybe also on:
http://www.imagemagick.org/discourse-server/viewtopic.php?f=1&t=11140&start=0&st=0&sk=t&sd=a
This Core Image filter section in the iOS dev library, possibly combined with the script referenced by Jonas and a little luck, might get you where you're going. Not sure, having never used either of these technologies.
I am implementing an iPhone application, in which I have implemented the following functionalities:
Select photo
Capture photo
Now I want to give a sketch effect to that photo like this one.
How could I do this?
If I may once again recommend it, my open source GPUImage framework has a built in filter that does just this. The GPUImageSketchFilter uses Sobel edge detection to highlight edges in black on images or video, leading to the exact same effect as seen in that application:
The above image was drawn from this answer, where I describe how that filter works, as well as show a couple other filter examples.
In fact, the SimplePhotoFilter example application that comes with the framework does exactly what you describe (capture a photo, apply a sketch filter to it, and save it to the photo library), so I'd start there if you want to get this up and running quickly.
OpenCV can be used to give sketch effect on image in iphone.
Refer iphone-how-to-convert-a-photo-into-a-pencil-drawing link and get helped.
Core Image filters are probably the best way to go.
http://developer.apple.com/library/ios/#documentation/GraphicsImaging/Reference/CoreImageFilterReference/.
For every developer arrives the day to improve the user interface experience because apps are evalutated mainly from the ui carefulness.
So, i've took a look around the websites and I found some psd where to start to desing my apps.
My question is: How to transform a psd prototype to a well-working app?
I don't unserstand how a mockup can help a developer to build a ui...
Can someone make me some clear the situation?
Well, I'd be careful to make a distinction between the graphics an app uses and the actual User Interface. Certainly the graphics are part of the UI, but the UI is soooo much more than that. Depending on how it is done, photoshop mock ups can be simple graphics you can use for your interface to complexes 'scenes' describing how the app functions. In the latter case, the mock-up can be useful for UI design, in the former case it just gives you pretty images to use (which can certainly be useful).
But to more directly answer your question, most people take 'slices' (individual pieces) of the photoshop image and export them as .png images (or .jpg). If the .psd file doesn't already have the images 'sliced', look up 'photoshop image slicing' on Google. You can then import them into Xcode and use them as background images for the controls you want to use. Especially since iOS 5.0, images can be used for a lot of controls. Also, you'll probably want to make sure you make the image resizable with proper UIEdgeInsets. This will allow the image to resize without pixilation by setting an area that can be tiled within the image.
I am not quite sure how use HD images for sprites in cocos2d. I looked through the documentation, and downloaded the newest beta which supports points instead of pixels, but I don't understand the whole -hd suffix idea. In other word I need help and have no idea how to use retina quality graphics in my cocos2d game. I feel that it is very simple, but I cannot find anything on doing this. Any help would be greatly appreciated.
Ok so maybe this is asking too much but, it would be very helpful if someone could give me the code a tell me where to put it. (Thats probably too much to ask) But if it is a line or too, it would be great if you could post it. I am absolutely clueless here. One thing I did try, was to set the content scale factor. The image was hi-def, but the fps went way down to around 12fps on an iPod touch 4th gen. I really do not understand this.
Thanks,
Tate
If you're using the latest beta, the only change you should need to make is export all your images at twice the size and use the "-hd" suffix, similar to Apple's "#2x". The documentation also says you need to set the content scale factor of the director, but in my case I didn't seem to need to do that.
Though it sounds like you've already read through it, I'll link to the documentation in hopes that someone will benefit.
I think the "-hd" is for Cocos2D-iPhone, the "#2x" is for icons used by Apple (e.g. Default.png).
If you want to see the difference, 1) setup slightly diff images (e.g diff colour, add minor changes) between normal and the "-hd" version, then 2) run it in simulator with "iPhone" (for iPhone 3 GS) and then with "iPhone(Retina)" (for iPhone 4+) and you should see different one been displayed.
Hope this helps.
What are some suggested "paths" for getting better at drawing in code in Cocoa? I think at this point, that's my biggest weakness. Is drawing in code something general, or Cocoa-specific?
Thanks!
- Jason
The best way is probably practice. Try drawing some simple things at first: a calendar (basically a grid), a custom button, or a digital clock.
Its also worth noting that a lot of 'custom' controls are made from images, so not that much of the drawing is done in code -- the only thing the code does is stitch those images together.
You might want to look at Opacity, a drawing app for OS X (I'm not affiliated with these folks, just discovered the app a few days ago). What sets Opacity apart from other drawing apps is that it can create Quartz code directly from your drawings. Naturally, the generated code is not perfect but in the few days I've been trying this app I've found it to be quite helpful in understanding how to use Quartz more effectively.
Drawing in code is need for creating custom controls no matter what UI toolkit you pick. Drawing in code certainly has its advantage, for example the application/framework that you are building is really lightweight come production time, cause there will be lot let resources(images/fonts/etc) to worry about.
Also if a problem arises changing drawing in code is a lot easier than to redo code and images together.
If you are doing Cocoa drawing start by looking at source code of BGHudAppKit and reading Cocoa Drawing Guide by Apple.
I'm in the same boat as you; I'd like to learn more about drawing code.
It's a big document, but the Quartz 2D programming guide on the developer website seems like a good place to start from. They introduce Graphics Contexts and Paths and include plenty of images.
There's also a book referenced in that document, Programming With Quartz: 2D and PDF Graphics in Mac OS X which looks good. The APIs for iPhone and OSX are almost identical, so there's no problem using a Mac OSX book.
So I'd suggest start with the Apple documentation (you don't need to read past the section on CGLayer drawing), try some sample code and figure out how it's working. Then move on to either that book or find more sample code on the web. Good luck!