Thursday, October 8, 2009

Start application without elevated privileges on Windows Vista and Windows 7

I finally found out how you do this. You sometimes have applications that have something like "install" or "setup" in their names. Windows Vista and Windows 7 are stupid enough to enforce administrator privileges when starting these applications. But often this is absurd and breaks the applications. Let's say it's a command that's called "InstalScript" that installs a new script to your application's settings directory, which is in the user's APPDATA path. Someone uses your application in a company that has a Windows Domain in-place and his user-account does not have administrator privileges, which is usually the case. This user would now be unable to use your script, because he can't run the InstallScript application.

Since the release of Vista I was always wondering how you could prevent this, but never took the time to google for a solution. At some point, I even assumed it was impossible. Well, it nearly is ;-) Since you are reading this article the chances are high you are developing for Windows. And the chances that you stumbled upon manifest-files are high in this case, too. If you ask me, .manifest is short for "Manifestation Of The Royal Pain In The Ass". But heck, this article is not about ranting against manifest-files. In this case, they are here to help you. You can specify which kind of privileges your application needs in your manifest-file, and when you set "requestedExecutionPrivileges" to "asInvoker", you are free to go! That's the information I found on many websites. Unfortunately, little of them mentioned where this actually should go, and because I'm no meanie, here's an example I took from MSDN:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0"> 
  <assemblyIdentity version=""
  <description>Installs Shrinky on your computer</description> 
  <!-- Identify the application security requirements. -->
  <trustInfo xmlns="urn:schemas-microsoft-com:asm.v2">

Now I can finally call Shrinky's Installer "ShrinkyInstaller.exe" and still debug it! (I put the manifest-file into the debug directory and named it "ShrinkyInstaller.exe.manifest). Yay!

Sunday, October 4, 2009

Shrinky Pre-Release

I had this idea in mind for a long time now. People are often asking me how they can resize images to a smaller file-size, most often because they want to send them via e-mail and don't want to wait 30 minutes for the e-mail to be sent. You can use Microsoft Paint which ships with every Windows for this and it's actually relatively easy to explain how. But most people can't remember the procedure and are lost when they have to do this the next time. So I came up with the idea to write an extremely easy application that can do this and is optimized for high usability and an easy interface. And here's my shot at it: Shrinky (doesn't that sound cute?).

Shrinky pre-release announcement

The only thing you have to do when loading Shrinky is clicking on the logo above, select the image-file you want to shrink and then hit "Shrink it!". This will create a file that's about 150-200kb in size, which is quite handy for uploading and sending via e-mail. A new file with the same file-name as the original, with a "-small" appended, will be created. You can tell Shrinky how to resize the image by clicking on "I want to decide myself".

Shrinky settings

You can shrink images in three different ways:

  • First, you can enter a file-size you want to have. This can be anything from "100kb" to "1,5 mb" (this is currently the only thing that does not work reliably, because floating-point values are not handled correctly). Shrinky will then try to create a file that matches this file-size as good as possible.

  • The second way to shrink a file is to enter the width and height directly. This can become handy when resizing an image so it fits in a certain space, such as on a webpage or something.

  • And the third way is by entering a percentage of the original resolution. Good for situations where you want to, for example, make an image half as big as it currently is.

When you are done setting up Shrinky the way you want, just hit "Shrink it".

Shrinky is completely written in C++ with Qt and is platform-independent. But obviously, since it's aimed at pc-beginners, the most important platform is Windows. That's why I've created binaries for Windows only (I don't have access to a Mac, anyways). See below for a download-link. You can access the source-code via the public git repository on github. Shrinky's currently translated to English and German only. Japanese will surely follow and some nice folks in #qt on freenode already offered translations, too. Man, open source is really nice. ;-)

There's still much to do to make Shrinky a polished product and publicly release it. Here's my todo-list for this project:

  • Shell-integration for Windows. Easily shrink images via right-click. That's especially important in the file-selection dialogs. With a tight integration, you can easily shrink images while selecting them in your e-mail application.

  • I need to write an installer for Windows, because extracting a ZIP-archive is not that easy for the target audience I am aiming at.

  • Processing of multiple files would be neat, too.

  • A web-page including a donation-facilty via paypal. Albeit being open-source, I'd like to make a few bucks with this application.

You can download the pre-release of Shrinky here. Just extract the zip-archive anywhere on your hard-drive (or usb-stick, for that matter) and run Shrinky.exe. You can post anything regarding your experience with Shrinky as a comment on this blog-post!