Stefano Tommesani

In a previous article named "Easy multi-thread programming Delphi", the AsyncCalls library was used to process multiple images at the same time. However, the processing of every single image was still strictly serial, even if image processing kernels are quite easy to accelerate spreading the load over multiple threads.

In this article we will see how the OmniThreadLibrary can be used to split a simple image processing kernel across multiple threads.

procedure TProcessedImage.EffectBlackWhite(Bitmap : TBitmap32);
var x, y : integer;
    Color : TColor32;
    Red, Green, Blue : Cardinal;
    Gray : Cardinal;
begin
  Bitmap.BeginUpdate;
  try
    for y := 0 to Pred(Bitmap.Height) do
        for x := 0 to Pred(Bitmap.Width) do
            begin
            Color := Bitmap.Pixel[x, y];
            Red := (Color and $00FF0000) shr 16;
            Green := (Color and $0000FF00) shr 8;
            Blue := Color and $000000FF;
            Gray := (Red * 299 + Green * 587 + Blue * 114) div 1000;
            //Io=(0.299Ri + 0.587Gi + 0.114Bi)
            Bitmap.Pixel[x, y] := Color32(Gray, Gray, Gray);
            end;
  except
  end;
  Bitmap.EndUpdate;
end;

This article is a description of the integration of Facebook authentication inside Friend Watchdog. It is not meant to be an introduction or a description of Friend Watchdog's features. Please click here for more information about Friend Watchdog.

Why authenticating on Facebook with Friend Watchdog

After authenticating on Facebook, the timeline in Friend Watchdog will contain not only the status of your friends over the past week, but also their activity on Facebook, such as what they posted on their wall, giving a broader overview of what they are doing on Facebook.

Please note that

1. enabling the Facebook authentication is optional, and it is not necessary for the main purpose of Friend Watchdog, that is checking when your friends are online
2. the data obtained with the Facebook authentication is not stored anywhere, not in your computer nor in the Friend Watchdog servers
3. the data obtained with the Facebook authentication is not sent or distributed in any way, so all the updates shown in the timeline are not transmitted to the Friend Watchdog servers

Friend Watchdog is now offline. There are several technical reasons for this choice, the first one being Microsoft dropping support for the chat API in Skype, the second one being Facebook changing the behaviour of their chat servers. But the most important reason is that a lot of people finally became aware that posting data on social networks is really a security risk, any criminal network can develop a system like Friend Watchdog to gain a disturbing insight into day-to-day life of their contacts. Friend Watchdog was designed to be limited in aggregating data about users, for example the FourSquare integration was never published as I felt it was too dangerous, but I am confident that there are similar spiders grabbing and presenting exactly this kind of information. So, as Friend Watchdog was meant to be a wake-up call to users of social networks, I think that the target was achieved, and it's time to turn it off.

Now I know what you did last monday Friend Watchdog monitors the state of your friends on Facebook and Skype, stores the status changes on remote servers, and lets you check when your friends have been online in the past week. Please note that you are sending status updates only when Friend Watchdog is up and running, and that status changes from multiple users are merged, so the more users of Friend Watchdog, and the more these users keep Friend Watchdog up and running, the more accurate will be the usage stats.
Your privacy is safe Why should you trust Friend Watchdog? Here is why: your Facebook account is NEVER sent to our servers, it is stored in encrypted form only on your computer, and it is used to access your Facebook account from your computer only. There is no way that we can access your Facebook account! we do not know who your Facebook and Skype friends are: the names of your friends are salted and hashed with SHA1, and only the hash is sent to the servers, so that we can distinguish between different friend names but we cannot retrieve friends' names from the hashes. For example, an Facebook username such as "stefanotommesani" generates this unique hash code: CDE381A6C6AD22E844263908022D40C4FE634C37. This hash code uniquely identifies the given Facebook username, but there is no way to go from the hash code back to the Facebook username, so the names of your friends remain private, and only you can see them once you allow Friend Watchdog to connect to the Skype application running on your PC (so that you don't even have to tell Friend Watchdog about your Skype password), it only reads the list of Skype friends and their online status, and that is the only information that is being monitored, always using hash codes to encrypt real names so that your privacy is safe the real names of your friends never leave your PC, only the hashes, that is the encrypted names that cannot be transformed back into the real names, are sent to the servers no need to register, no need to open an account, no need to pay anything, just download the software and run it on your PC

At the time of writing, the SkyDrive client application on Windows does not support bandwidth throttling on uploads, so if you start uploading a large number of files, it will try to use all the available bandwidth, and this behaviour has an impact on other applications accessing the Internet.

A quick fix to this behaviour is:

• install a network traffic manager app, such as SeriousBit NetBalancer (I will use NetBalancer in this example)
• start SkyDrive app
• start NetBalancer, and look for the SkyDrive process (SkyDrive.exe), right-click to open the menu, and choose Upload Priority | Limit...