I want build a sketch pad app on iPhone, I assume that this type app has already been developed long time , maybe some open source code can be use for this purpose ?
anyone can give tip on this field ?
Thanks ...
Take a look at the Sketch example for MacOS X Cocoa, then at UIBezierPath. Much of the drawing code should be easily portable with a regexp, although the UI and controller would need rewriting.
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I'm been developing for iOS for about 6 months now and have an idea for an app which reqires that the user touch input is traced on the screen.
My experience with iOS development is solely with navigation-style application so I've never had to deal with any graphical frameworks.
So my question is what framework(s) should I use the accomplish this?
The path tracing will be the only graphical part of the app so I feel that some game-development frameworks like openGL ES and cocos2d may be overkill; but then again I don't know.
Thanks in advance for any help!
The simplest way is to use CGPathRef/CGMutablePathRef/UIBezierPath, which are part of Quartz and UIKit (which you should already be familiar with.) Use the touch points to construct your path. Create a subclass of UIView, and in its -drawRect: method, draw the path.
Does that help?
I need to implement on-screen drawing feature within one of my apps. I would imagine it would be an on-screen transparent overlay. I'm looking to be able to trace the finger path and leave a line, select colors and have erase/undo feature.
I did some research of what's currently on the app store, and a lot of those apps look similar and use similar brushes.
Something tells me that they look too much alike for this to be a coincidence. Does apple provide any built-in finger painting canvas, or are there some widely-known open source projects for on-screen drawing?
Thank you!
I ran into the same thing while looking for examples when I got started with drawing, so I released my efforts as a sample project called SimpleDrawing. I tried to keep things basic while supporting most/all of the standard drawing tools and operations.
There is the GLPaint project, which you can get here.
Other than that, you could use CoreGraphics & -touchesBegan:withEvent: if you wanted.
I want to implement a functionality similar to found in Pages app..i.e. text floating around images, image zooming etc.. I have been struggling with this part of my application but no success yet. Would be grateful if someone provides me with some pointers in this regard , like 'Which UIControl should I use?','Help in thinking logic' etc..
Thanx in advance.
Sounds like a fun app to develop.
Some Pointers:
Immediately off the bat, I would say look into creating your own Controls for the floating objects.
I would suggest tackling a smaller project, or maybe a few small to medium size projects. p
Try making a few apps with WinForms or WPF. Also look into XSL:FO.
Immediately off the bat, I would say look into creating your own Controls.
There was a WWDC session that talked about iOS text. I don't think it's violating NDA to say this is going to be a very hard project. No, make that very, very, very hard.
You will probably need to do all UI yourself, and use Core Text for rendering of the text. (But I believe you need to draw selection, etc.) And do the layout yourself.
If you look at the Notes app on the iPad, you can see it uses all native iPhone controls, but they're "skinned" to look like a pad of paper. What's the best way to implement something similar to that? Could I use interface builder and simply change the background image for each of the controls, including the TableViews?
Thanks in advance for all your help! I'm going to continue researching this question right now.
This article from Dr Touch will probably come in handy: Stuff you learn from reverse engineering Notes.app
It's a little more complicated than that. My suggestion is manifold:
Hire a real designer to make the artwork.
Subclass whatever controls you want to skin, and handle this business directly in drawRect:. Interface Builder will not help you in this instance.
Consider drawing your controls programmatically instead of using images; a really cool thing would be to cache the programmatic drawings so that they only have to be performed once.
Best of luck!
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!