tag:blogger.com,1999:blog-70235769296063694072026-05-22T23:16:47.065+02:00A blog about anything a software engineer might encounter during his programming efforts.Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.comBlogger20125tag:blogger.com,1999:blog-7023576929606369407.post-50894864220338341802012-11-28T10:23:00.000+01:002015-11-29T10:23:21.848+01:00

In order to easily rotate an image in 3D space, I have written a simple method that will do just that. It accepts rotations (in degrees) along each of the three axis (x, y and z), with 90 degrees being the "normal" position. It also supports translations along each of the axis, and a variable focal distance (you would usually want the focal distance to be the same as your dz). The parameters are

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com33tag:blogger.com,1999:blog-7023576929606369407.post-67838510477082488162012-10-26T18:16:00.000+02:002012-11-28T11:18:22.138+01:00

It seems OpenCV does not provide very much support for transparent images. It has images with 4 channels, which are treated as BGRA images, with the fourth channel being the Alpha channel. It also supports saving these images using the PNG format, yet it does not support properly displaying these images in highgui, nor does it support combining these images. I have looked a while for a

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com58tag:blogger.com,1999:blog-7023576929606369407.post-51337521871151942792012-07-11T21:55:00.000+02:002012-07-31T14:37:34.241+02:00

After some trouble installing OpenCV 2.4 in Windows and using it with Visual C++ 2010, I decided to write a post about this, so I can hopefully save you some time figuring this one out. It is based on this wiki, but that describes how to build with CMake etc, which is not necessary (anymore?). Okay, so first you need to download OpenCV 2.4 here. After downloading, you need to extract it. I

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com297Rijen, The Netherlands51.5841138 4.924198951.5446483 4.8452349 51.623579299999996 5.0031629tag:blogger.com,1999:blog-7023576929606369407.post-81477701469301571922012-02-09T20:22:00.000+01:002012-02-12T14:24:12.014+01:00

Let's start with adding the Facebook like button. On this page: https://developers.facebook.com/docs/reference/plugins/like/, you can create the button as you would like it to appear on your site. When you press "Get Code", you'll get 2 pieces of code. First we have to add the JavaScript code. To do this, open your head.phtml page, which can be found here: app/design/frontend/<your template&

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com0tag:blogger.com,1999:blog-7023576929606369407.post-18251953789548505392011-11-29T10:14:00.001+01:002012-02-12T19:12:01.124+01:00

Today one of the internal web applications that we have wouldn't run properly on my development machine (it works fine on the production server). When opened it would produce the following exception: Error during serialization or deserialization using the JSON JavaScriptSerializer. The length of the string exceeds the value set on the maxJsonLength property. It seems that the production

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com2tag:blogger.com,1999:blog-7023576929606369407.post-75228256648355103852011-11-22T20:27:00.003+01:002011-12-06T11:16:02.420+01:00

It seems that a lot of people do not know of the existence of this handy little operator, so I decided to put it up here, so it may help somebody clean up their code. Have you ever had a Nullable<...> type which you needed to read to a regular value type, but needed a "default" value for when it was NULL, as the regular value type cannot handle it? Chances are, you've written it

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com0tag:blogger.com,1999:blog-7023576929606369407.post-68538089982479737042011-11-22T20:15:00.001+01:002014-07-08T11:47:10.693+02:00

After including a view I have in my database in an Entity Framework data model, I noticed that for some strange reason, the result was showing duplicates. When a set should have for instance 10 different rows, it might contain only 4 different rows, some of which were duplicated so it was still a total of 10 rows. The view itself showed the correct results, but when called from code using the

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com21tag:blogger.com,1999:blog-7023576929606369407.post-57573186273061925972011-11-22T20:06:00.000+01:002012-02-12T19:11:25.965+01:00

If you have created a task within Windows Task Scheduler, you might encounter a task that does not run properly. When you look into the history of the task, you might find the following error message: Task Scheduler failed to start instance "<guid value>" of "<task name>" task for user "<user name>" . Additional Data: Error Value: 2147942667. The reason for this error is the

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com20tag:blogger.com,1999:blog-7023576929606369407.post-90307607284953489132011-02-25T22:17:00.005+01:002011-02-25T23:08:51.832+01:00

If you want to create the database structure for using Forms Authentication in your Windows Azure hosted ASP.Net application, you'll probably have noticed that running aspnet_regsql.exe on your Azure database doesn't work. I have tried merging a local database using Red Gate SQL Compare 9 (you can of course also use the SQL Azure Migration Wizard), but that also gave me some errors regarding some

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com0tag:blogger.com,1999:blog-7023576929606369407.post-7259552730316896022011-01-09T22:10:00.003+01:002011-01-21T17:09:33.274+01:00

Ever noticed how the time Thread.Sleep(int x) waits is not equal to x? I just noticed it happening with 2 threads with different values for the sleep, yet they were running just as quick. After some research I discovered that the .Net runtime and Windows map this to a lower resolution in time, due to the way they handle threads. According to some sites it is 15.6 ms. This means that any x between

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com3tag:blogger.com,1999:blog-7023576929606369407.post-33570844936315423112011-01-05T20:08:00.005+01:002011-01-07T19:10:06.332+01:00

If you have ever used a call to Response.Redirect("url"), Response.End() or Server.Transfer() within a try block, you will probably have noticed that these calls always throw a ThreadAbortException. This is normal behaviour, but can mess up your program if the corresponding catch is executed unexpectedly. To avoid this, catch the ThreadAbortException in a separate catch, or write a

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com0tag:blogger.com,1999:blog-7023576929606369407.post-53431646341295658482010-12-30T15:54:00.009+01:002011-01-05T21:07:56.026+01:00

This exception is produced by Crystal Reports when the maximum number of concurrent report processes have been initiated. I have had troubles with this exception in my asp.net application, but at first it seemed almost to occur at random. Recycling the app pool solved the problem when it occurred. After a while (when the application was used more intensively) this became a real problem, as

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com9tag:blogger.com,1999:blog-7023576929606369407.post-34802572569276386602010-12-30T09:49:00.005+01:002011-01-17T10:11:19.412+01:00

I was having trouble with this error today, when I was trying to build a Deployment package. I also noticed that my deployment package showed no Detected References anymore. The weird thing was, that my solution build properly and I could even run the software. It was just the deployment package that was producing errors. As I found, the first thing to check is missing references. If they are

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com4tag:blogger.com,1999:blog-7023576929606369407.post-62368003730141557892010-12-22T16:48:00.005+01:002011-01-05T21:05:16.083+01:00

Today I was having trouble with an ASP.Net Menu control that kept a bit of empty space above, which made it render too low in the div element it was supposed to stay inside of: This problem just came out of nowhere, one day my menu is showing as it should, the next day, it is not. I even tried rolling back to the older version of the files, but somehow this didn't change a thing. It might have

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com12tag:blogger.com,1999:blog-7023576929606369407.post-1212488873090323922010-12-21T15:58:00.003+01:002011-01-09T19:01:41.763+01:00

In Microsoft SQL Server, it is possible to reseed an identity column of a table. If you want to start an identity column at a different value (for instance, after clearing it), you can use the following syntax: DBCC CHECKIDENT (myTable, reseed, 0) The next row that is added to the table will have 1 in its identity column. If we would useDBCC CHECKIDENT (myTable, reseed, 41)the next row would

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com0tag:blogger.com,1999:blog-7023576929606369407.post-27896801482673634472010-12-20T19:15:00.010+01:002011-11-22T20:38:41.484+01:00

After storing various values as strings in a database, I had some troubles with parsing these values back to their original types (doubles, datetimes, etc.) on various clients. As it seems, the most commonly used ways (such as ToString(), Convert.ToString(), Convert.ToDecimal() and DateTime.Parse()) perform these conversions based on the current culture. This means that the whole format of a

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com0tag:blogger.com,1999:blog-7023576929606369407.post-85302522492754836712010-12-17T12:51:00.008+01:002012-07-12T20:09:18.867+02:00

The full exception is: Could not load file or assembly 'System.Data' or one of its dependencies. An attempt was made to load a program with an incorrect format. This problem seems to occur rather a lot and it seems there are different causes for it to occur. I have had this problem today and the information I found on the internet did not help at all. I have tried setting System.Data to not copy

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com14tag:blogger.com,1999:blog-7023576929606369407.post-84816258470291250482010-12-16T11:51:00.009+01:002010-12-17T20:21:43.503+01:00

I just discovered that SQL Server often returns the wrong week number when using DatePart(wk, @date). For instance, SELECT DatePart(wk, '2010-12-17') returns 47 while it should be 46. This is because SQL Server starts counting weeks from 1 Jan, so 1 Jan is always in week 1 of the year. The ISO standard states that week 1 is the first week with 4 days in it. The following code can be used (with @

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com3tag:blogger.com,1999:blog-7023576929606369407.post-34256384154419215172010-12-16T11:04:00.002+01:002012-01-04T10:17:46.486+01:00

Given a year and a weeknumber, you can calculate the date of the Nth day of that week. The best way to do this as far as I have been able to come up with is this: public static DateTime GetNthDayOfWeek(int year, int weeknumber, int n, CultureInfo culture) {   // Get 1st jan of given year   DateTime date = new DateTime(year, 1, 1);   // Get the weeknumber of this

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com0tag:blogger.com,1999:blog-7023576929606369407.post-53011274630276767722010-12-16T10:46:00.006+01:002011-11-22T20:39:36.458+01:00

The easiest way to get a culture specific weeknumber is the following: culture.Calendar.GetWeekOfYear(inputDate,      culture.DateTimeFormat.CalendarWeekRule,      culture.DateTimeFormat.FirstDayOfWeek); Where culture is the culture you wish to use for determining the weeknumber. To use the current culture, you can use the following: CultureInfo culture =

Michael Jepsonhttp://www.blogger.com/profile/16073118583952778532noreply@blogger.com0