I'm just learning to use XCode and program in Objective-C (my plan is to write a an app we need for my business since I can't find one that does what I need). It's going well and as an exercise I've been playing with database apps and screensavers.
I'm trying to write a screensaver that all it does is to show 3 or 4 pictures randomly floating on the screen. Similar to the out of the box pictures screensaver that comes with Mac OS X.
I've played with the code in http://cocoadevcentral.com/articles/000088.php and while very informative I still don't know how to add those 3 or 4 pictures and make them move.
Anyone out there can point me to sample code? Or a project that I can use as reference?
Again, this is just self learning.
Thank you!
This will probably be your first port of call.
My approach to this was to create a Quartz Composition using Quartz composer. I found this easier than figuring out how to draw and animate everything by hand.
You can display a quartz composition inside a ScreensaverView by using the QCView class. This setup worked well for me.
Related
I am having a cocoa application for mac in objective c.
I am slightly new to mac application.
In my app, I want to implement growing imageview animation like shown below in the images.
As seen from the screenshots, when my window loads, I have some data to feel as it increases its value.
From 0 to the maximum value.
It should show like its rising from 0 to the values that I have specified.
I have seen lots of circular animations but didn't get much idea from that.
please give me suggestions on this.
Please ignore if mistakes as I am new to mac development.
Thanks in advance.
You should create mask and apply it to NSImageView layer object using the only image (one for 100%).
Read following article and don't be afraid it's about iOS-development, CoreAnimation is available in Cocoa too.
OK so I want to record the screen of a Mac directly to a .mov or .m4v. I've taken a look at Son of Grab from Apple, but I would prefer not to deal with screenshots and individual images and just work with video.
I thought there should be something in QTKit but I can't find it. I know this can be done in OpenGL, but 1) I don't know how and 2) I'd like to avoid that if possible.
Just to elaborate, I am recording from iSight using QTCaptureDeviceInput and (obviously a QTDevice) because I need to solution to work on Snow Leopard.
It seems like there should be a way to just target the screen as the input device for QTMediaTypeVideo.
Any help would be greatly appreciated.
You can use AVFoundation to do screen recording on the Mac. It's only available on 10.7 though.
You can use CGDisplayCreateImage/CGDisplayCreateImageFromRect APIs (10.6+) to obtain still images of screen and then making a movie out of them.
I'm not sure how good will be the performance though.
I have found that when faced with the question, will it be fast enough or not, just give it a try. Do a quick test by gabbing frame after frame say 1000 times and time it. CGDisplayCreateImageFromRect is not that hard to call at all. I have called it for single screen shots of the whole screen when the mouse was clicked, and it hardly slowed my mac down (only a basic dual core machine).
Apple has two samples showing the main two ways this can be done: :-
ScreenSnapshot
SonOfGrab
It would be easy to modify these to do it say 1000 times in a loop!
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!
Hi i'm thinking about making midi step sequencer and I need to make a note grid/matrix that resizes/ adapts when you zoom. I've been searching for different ways of doing this but cant figure out a way that works well.
I thought about drawing cell objects made with (NSRect) but I couldn't figure out how to get the right interaction when resizing.
This is my first "biggish" OBJ-c project so please don't kill me, im still battling with the frameworks and the syntax is so foreign to me.
You could use Core Animation layers to create your grid.
Take a look at Apple's Geek Game Board sample code project:
http://developer.apple.com/library/mac/#samplecode/GeekGameBoard/Introduction/Intro.html
The code shows a way to display different kinds of card/board games using CALayer.
The Checkers game looks to be the closest to the grid you want to create.
What is the best way to create a numeric pad like the one Apple uses in the telephone app?
I would say just create an array of UIButton objects so that you can utilize UIControlStateSelected and the other button states by using different images for different states.
Another idea is to create something similar to that entire keypad in Photoshop, and then tile it into 12 images using http://www.mikelin.ca/blog/2010/06/iphone-splitting-image-into-tiles-for-faster-loading-with-imagemagick/
That would take some of the work out of get all the images to flow nicely together.
By the way, I just forgot about these until just a minute ago... they have some of the UI graphics from the iPhone and iPad in high res PSD file:
http://www.teehanlax.com/blog/2010/02/01/ipad-gui-psd/
and
http://www.teehanlax.com/blog/2010/08/12/iphone-4-gui-psd-retina-display/
and
http://www.teehanlax.com/blog/2010/06/14/iphone-gui-psd-v4/
I implemented a KeypadView, that is customizable via a delegate.
This github repository has the KeypadView and a delegate-implementation.
As I am still beginner in the field of iOS development I would appreciate, if you share your thoughts with me.