HP Sprout – Blended Touch and Projection All-in-One PC

Well, that thing looks promising.
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Posted in Hardware, Multi-Touch, Natural User Interfaces, Projection, Tangible Interfaces

Find and Delete Empty Files Using a Shell Script on the Command Line


If you – like me – copy image files regularly to an external HD, you might also have come across the problem that sometimes the file references are created but the eventual copying of the file contents failed. Thus, I regularly end up with a lot of dead files that block the way for the real files when I want to copy the actual files later.
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Posted in bash, Command Line

Objective-C Category for Location Authorization Request for iOS8 with Xcode 5 Support


When you use the location of the user in your app and want also your iOS8 users to be able to enable using their location, you have to explicitly ask the user for it using this or this selector. There are two problems connected to that:
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Posted in iOs, iPad, iPhone, Objective-C

Provision iOS IPA App for In-House Enterprise Distribution


Provisioning an iOS app for in-house distributione is damn complicated. As my efforts to do so were eventually successful, I decided to prepare this comprehensive tutorial documenting my best practice approach for future reference.
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Posted in apple, iOs, iPad, iPhone

Fix Broken WordPress RSS Feed Due to HTML Above the XML Declaration

HTML Code Before XML Declaration in  RSS Feed

I had the problem that my RSS feed was broken due to HTML that appeared above the XML declaration.
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Posted in PHP, Wordpress

A Gesture-Controlled Car User Interface

Well, the title says it all: »A New Car UI: How touch screen controls in cars should work«. I am not convinced that car user interfaces should work exactly that way but I have to admit that the user interface of this prototype is intriguing.
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Posted in Car UI, Gestures, HCI, UI Prototypes Tagged with: Car, Prototype, UI

Bash Script Batch Rename Image Files Employing Parameter Expansion


This one is a classic in the use of shell scripts: batch renaming (image) files. You can find solutions on how to batch rename files on stackoverflow (e.g., here and here).
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Posted in bash

Prevent Opening Additional Popover View from Navigation Bar Button Using UIPopoverController


In a recent iOS project for the iPad, I wanted to open a popover view from a bar button in the navigation bar. However, tapping somewhere on the navigation bar would not dismiss the popover view but (depending on where I tapped on the bar) open an additional popover view or even navigate to another view controller.
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Posted in Cocoa, iOs, iPad

Creating Animated GIFs from the Command Line in Mac OS X Using Convert


You can easily create animated GIFs from the command line in Mac OS X (or Linux) using ImageMagick. To figure out if ImageMagick is installed open the application Terminal from the Utilities folder in Applications, type ‘convert’ and hit ‘Enter’. If something like »Version: ImageMagick 6.6.9-3 2011-04-04 Q16« and lots of options appear, ImageMagick is installed and you can proceed. If not, you can install it using MacPorts (look for ‘Mac OS X Binary Release’). install it using homebrew or MacPorts.
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Posted in Command Line Tagged with: animated gif, commandline, imagemagick

SimProj: A Tool for the Calculation of Rear-Projection Mirroring

Screenshot of SimProj Application

The SimProj Project provides a Processing-based (and therefore Java-based) application that provides a GUI for the simulated calculation of a video projection setup. SimProj allows to add and manipulate virtual projectors, mirrors and projection planes in order to show how the projection is mirrored and which sizes, angles and positions the setup components require. SimProj can be configured to comfortably show all necessary measures that can be ‘easily’ (everyone who has ever built a rear-projection setup knows what ‘easily’ means in that context) transferred to the hardware setup.

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Posted in DIY, Multi-Touch, Projection, Video Projection

About Johannes

I am a freelance software developer based in Wiesbaden, Germany. I develop as well user interfaces for mobile, tablet or tabletop devices as web frontends and backend applications. You can check out my skills in XING or Linked In.

I am also a researcher in the field of interactive surfaces. Check out my publications.

Read a little bit more about me…

My Multi-Touch Tables