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  • How to find patterns (lines, circles,...) from a list of points?

    - by Burkhard
    I have a list of points. Each point being an x and y coordinate (both of which are integers). Now I'm trying to find known patterns, such as lines, arcs or circles, knowing that the points are not perfectly on the pattern. What's the best way to do it? I don't have many clues to get started. Edit: the points are ordered. The user is drawing something and the program should detect the best patterns. For instance, if a triangle is drawn, it should detect three lines.

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  • Tender vs. Requirements vs. Solution Design

    - by Tom Tom
    Conventionally, which of the above documents is deemed to hold the most weight when it comes to system acceptance? I recently had a conversation along these lines: It was argued that the initial requirements / tender documentation should be used to determine system acceptance. It was said that the solution design only serves to describe the way in which the system will solve the problem, not the problem it will solve. Furthermore, it was argued that if requirements are missed during solution design, the requirements should be referenced during system acceptance and that if any requirements were missed then the original tender should be referenced. Conversely, I suggested that - while requirements may be based on the original tender - they supersede it once agreed with the stakeholders. Furthermore, during solution design, analysis is performed to address and refine these initial requirements, translating them into a system capable of meeting the actual requirements. Once signed off by the relevant users, this solution design should absolutely represent the requirements (by virtue of the fact that it's designed upon them) but actually supersedes them as the basis for system acceptance. Is one of the above arguments more valid than the other?

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  • Why is Mac supposedly better than Windows for graphics?

    - by Svish
    Ok, people just keep telling me that if you're going to be working with graphics and design and stuff, you should get a Mac. And I just don't get the logic. Because most of these people would be working with Adobe software, which are for both Windows and Mac. To me it seems like their whole argument is based on that "everyone else does". Like, Mac had some graphics software that Windows didn't earlier in history, so most people were using Mac. And since most people were using Mac, new people also started using Mac. And since most people were using Mac, schools and universities used Mac. Which taught new people to use Mac. So they were using Mac. And told everyone they met that everyone they knew were using Mac. And so on. Anyways... What is the deal really? Is there actually any advantage in using Mac for graphics and design and such things? My take is that you pretty much have the same software and both Mac and Windows are powerful enough, support enough RAM, are stable (as long as you don't install lot's of junk or faulty drivers), et cetera. So, can anyone give me a good explanation on this? Is there a real difference or are people just brainwashed?

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  • Examples of IOC/DI over Singleton

    - by Amitd
    Hi, Just started learning/reading about DI and IOC frameworks. Also I read many articles on SO and internet that say that one should prefer DI/IOC over singleton. Can anyone give/link examples of exactly how DI/IOC eliminates/solves the various issues regarding the Singleton pattern? (hopefully code and explanation for better understanding) Also given a system has already implemented Singleton pattern, how to refactor/implement DI/IOC for the same? (any examples for the same?) (Language/Framework no bars..C# would be helpful) Thanks

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  • JFace Providers and MVC/MVP/etc.

    - by Alexey Romanov
    Where do the JFace providers belong in an MVP or MVC architecture? Or should Provider pattern be treated as a different way of View-Model separation? If so, is it the same as the ASP.NET Provider pattern? Is there an article on a proper design of JFace applications using Providers?

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  • Implementing the procducer-consumer with .NET 4.0 new

    - by bitbonk
    With alle the new paralell programming features in .NET 4.0, what would be a a simple and fast way to implement the producer-consumer pattern (where at least one thread is producing and enqueuing task items and one other thread executes (dequeues) these tasks). Can we benfit from all these new APIs? What is your preferred implementation of this pattern?

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  • When NOT to use MVVM?

    - by Vitalij
    I have started using MVVM pattern recently. I have had several projects where I used it and with every new one, I start to see that it will fit great within that new project. And now I start to ask myself are there situation when it's better NOT to use MVVM. Or is it such a nice pattern which you can use anywhere? Could you please describe several scenarios where MVVM wouldn't be the best choice?

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  • MVVM pattern and nested view models - communication and lookup lists

    - by LostInWPF
    I am using Prism for a new application that I am creating. There are several lookup lists that will be used in several places in the application. Therefore it makes sense to define it once and use that everywhere I need that functionality. My current solution is to use typed data templates to render the controls inside a content control. <DataTemplate DataType={x:Type ListOfCountriesViewModel}> <ComboBox ItemsSource={Binding Countries} SelectedItem="{Binding SelectedCountry"/> </DataTemplate> <DataTemplate DataType={x:Type ListOfRegionsViewModel}> <ComboBox ItemsSource={Binding Countries} SelectedItem={Binding SelectedRegion} /> </DataTemplate> public class ParentViewModel { SelectedCountry get; set; SelectedRegion get; set; ListOfCountriesViewModel CountriesVM; ListOfRegionsViewModel RgnsVM; } Then in my window I have 2 content controls and the rest of the controls <ContentControl Content="{Binding CountriesVM}"></ContentControl> <ContentControl Content="{Binding RgnsVM}"></ContentControl> <Rest of controls on view> At the moment I have this working and the SelectedItems for the combo boxes are publising events via EventAggregator from the child view models which are then subscribed to in the parent view model. I am not sure that this is the best way to go as I can imagine I would end up with a lot of events very quickly and it will become unwieldy. Also if I was to use the same view model on another window it will publish the event and this parent viewmodel is subscribed to it which could have unintended consequences. My questions are :- Is this the best way to put lookup lists in a view which can be re-used across screens? How do I make it so that the combobox which is bound to the child viewmodel sets the relevant property on the parent viewmodel without using events / mediator. e.g in this case SelectedCountry for example? Any alternative implementation proposals for what I am trying to do? I have a feeling I am missing something obvious and there is so much info it is hard to know what is right so any help would be most gratefully received.

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  • CheckBox Command Behaviors for Silverlight MVVM Pattern

    - by Blake Blackwell
    I am trying to detect when an item is checked, and which item is checked in a ListBox using Silverlight 4 and the Prism framework. I found this example on creating behaviors, and tried to follow it but nothing is happening in the debugger. I have three questions: Why isn't my command executing? How do I determine which item was checked (i.e. pass a command parameter)? How do I debug this? (i.e. where can I put break points to begin stepping into this) Here is my code: View: <ListBox x:Name="MyListBox" ItemsSource="{Binding PanelItems, Mode=TwoWay}"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <CheckBox IsChecked="{Binding Enabled}" my:Checked.Command="{Binding Check}" /> <TextBlock x:Name="DisplayName" Text="{Binding DisplayName}"/> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> ViewModel: public MainPageViewModel() { _panelItems.Add( new PanelItem { Enabled = true, DisplayName = "Test1" } ); Check = new DelegateCommand<object>( itemChecked ); } public void itemChecked( object o ) { //do some stuff } public DelegateCommand<object> Check { get; set; } Behavior Class public class CheckedBehavior : CommandBehaviorBase<CheckBox> { public CheckedBehavior( CheckBox element ) : base( element ) { element.Checked +=new RoutedEventHandler(element_Checked); } void element_Checked( object sender, RoutedEventArgs e ) { base.ExecuteCommand(); } } Command Class public static class Checked { public static ICommand GetCommand( DependencyObject obj ) { return (ICommand) obj.GetValue( CommandProperty ); } public static void SetCommand( DependencyObject obj, ICommand value ) { obj.SetValue( CommandProperty, value ); } public static readonly DependencyProperty CommandProperty = DependencyProperty.RegisterAttached( "Command", typeof( CheckBox ), typeof( Checked ), new PropertyMetadata( OnSetCommandCallback ) ); public static readonly DependencyProperty CheckedCommandBehaviorProperty = DependencyProperty.RegisterAttached( "CheckedCommandBehavior", typeof( CheckedBehavior ), typeof( Checked ), null ); private static void OnSetCommandCallback( DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e ) { CheckBox element = dependencyObject as CheckBox; if( element != null ) { CheckedBehavior behavior = GetOrCreateBehavior( element ); behavior.Command = e.NewValue as ICommand; } } private static CheckedBehavior GetOrCreateBehavior( CheckBox element ) { CheckedBehavior behavior = element.GetValue( CheckedCommandBehaviorProperty ) as CheckedBehavior; if( behavior == null ) { behavior = new CheckedBehavior( element ); element.SetValue( CheckedCommandBehaviorProperty, behavior ); } return behavior; } public static CheckedBehavior GetCheckCommandBehavior( DependencyObject obj ) { return (CheckedBehavior) obj.GetValue( CheckedCommandBehaviorProperty ); } public static void SetCheckCommandBehavior( DependencyObject obj, CheckedBehavior value ) { obj.SetValue( CheckedCommandBehaviorProperty, value ); } } I used this article to get me started, but I'll readily admit this is over my head.

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  • Question on MVVM pattern on WPF ?

    - by Ashish Ashu
    I have a user control let say UC1 . This user control have viewmodel UC1_vm. In the usercontrol UC1 I have a canvas in which drawing curve logic is implemented. This drawing curve logic is based on the data points property in the view model ( UC1_vm). The data points property inside the view model change with different condition. The generation of data points is written in the View Model. I want to bind the data points property in the view model to the draw curve logic inside the User control (view). I want whenever the data point property is changed in the view model , the canvas calls the draw curve method. Can I set the set any property of canvas which when changed it calls the on paint logic auto matically? Please suggest me the approach of implementing this scenario!!

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  • Page navigation in silverlight 4 using MVVM pattern

    - by Archie
    Hello, I have a a navigation application developed in Silverlight 4. It has a main page which contains a frame. I load a particualr view in that frame and I know that I can use NavigationService to navigate to other page which would be loaded in the same frame. But my question is how it can be done using MVVM? To get the frame do I need to pass the reference of the page? Also, as per my knowledge one view is not aware of any other views. So what is the best way to make them aware of each other? I have heard of Controller and Mediator but how shall I implement them so as to get the Frame of the mainpage? It would be very helpful if anyone can give me the example or probably sample code for this. Thanks in advance.

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  • Query on MVVM design pattern on WPF.

    - by Ashish Ashu
    I am using MVVM architecture. I have a usercontrol UC as a View Model is a ModelData class ViewModel (UCViewModel) is binded to a usercontrol. I have three more usercontrols that is inside the usercontrol UC ( discussed above). Let's say uc1, uc2 and uc3. and the visibility of uc1 , uc2 and uc3 inside UC depends on the type selected ( which ever radio button is selected ). Since UC is binded to UCViewModel and I have to do all the stuff related to uc1 , uc2 and uc3 inside UCViewModel. Can I have seperate VM to uc1 , uc2 and uc3.. if Yes how can i do that ? Please Help!!

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  • java Filter URL pattern specific to request params

    - by Rohit Desai
    Hi All, We have a situation where we want to use filter for URL's containing some specific request parameters. e.g htt://mydomain.com/?id=78&formtype=simple_form&....... htt://mydomain.com/?id=788&formtype=special_form&....... and so on , id are fetched at run time, I want configure filter in web.xml only if formtype=special_form. How should achieve the solution . Can filter be configure with regex patterns? Really appreciate your help on this. Thanks, Rohit

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  • Single Table Inheritance (Database Inheritance design options) pros and cons and in which case it us

    - by Yosef
    Hi, I study about today about 2 database design inheritance approaches: 1. Single Table Inheritance 2. Class Table Inheritance In my student opinion Single Table Inheritance make database more smaller vs other approaches because she use only 1 table. But i read that the more favorite approach is Class Table Inheritance according Bill Karwin. My Question is: Single Table Inheritance pros and cons and in which case it used? thanks, Yosef

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  • TypeInitializeException on MVVM pattern

    - by Mohit Deshpande
    System.TypeInitializationException was unhandled Message=The type initializer for 'SmartHomeworkOrganizer.ViewModels.MainViewModel' threw an exception. Source=SmartHomeworkOrganizer TypeName=SmartHomeworkOrganizer.ViewModels.MainViewModel StackTrace: at SmartHomeworkOrganizer.ViewModels.MainViewModel..ctor() at SmartHomeworkOrganizer.App.OnStartup(Object sender, StartupEventArgs e) in C:\Users\Mohit\Documents\Visual Studio 2010\Projects\SmartHomeworkOrganizer\SmartHomeworkOrganizer\App.xaml.cs:line 21 at System.Windows.Application.OnStartup(StartupEventArgs e) at System.Windows.Application.<.ctor>b__0(Object unused) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter) at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) at System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) at System.Windows.Threading.DispatcherOperation.InvokeImpl() at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state) at System.Threading.ExecutionContext.runTryCode(Object userData) at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData) at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Windows.Threading.DispatcherOperation.Invoke() at System.Windows.Threading.Dispatcher.ProcessQueue() at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled) at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o) at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter) at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) at System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler) at System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Boolean isSingleParameter) at System.Windows.Threading.Dispatcher.Invoke(DispatcherPriority priority, Delegate method, Object arg) at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam) at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg) at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame) at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame) at System.Windows.Threading.Dispatcher.Run() at System.Windows.Application.RunDispatcher(Object ignore) at System.Windows.Application.RunInternal(Window window) at System.Windows.Application.Run(Window window) at System.Windows.Application.Run() at SmartHomeworkOrganizer.App.Main() in C:\Users\Mohit\Documents\Visual Studio 2010\Projects\SmartHomeworkOrganizer\SmartHomeworkOrganizer\obj\Debug\App.g.cs:line 0 at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args) at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args) at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart() InnerException: System.ArgumentException Message=Default value type does not match type of property 'Score'. Source=WindowsBase StackTrace: at System.Windows.DependencyProperty.ValidateDefaultValueCommon(Object defaultValue, Type propertyType, String propertyName, ValidateValueCallback validateValueCallback, Boolean checkThreadAffinity) at System.Windows.DependencyProperty.ValidateMetadataDefaultValue(PropertyMetadata defaultMetadata, Type propertyType, String propertyName, ValidateValueCallback validateValueCallback) at System.Windows.DependencyProperty.RegisterCommon(String name, Type propertyType, Type ownerType, PropertyMetadata defaultMetadata, ValidateValueCallback validateValueCallback) at System.Windows.DependencyProperty.Register(String name, Type propertyType, Type ownerType, PropertyMetadata typeMetadata, ValidateValueCallback validateValueCallback) at System.Windows.DependencyProperty.Register(String name, Type propertyType, Type ownerType, PropertyMetadata typeMetadata) at SmartHomeworkOrganizer.ViewModels.MainViewModel..cctor() in C:\Users\Mohit\Documents\Visual Studio 2010\Projects\SmartHomeworkOrganizer\SmartHomeworkOrganizer\ViewModels\MainViewModel.cs:line 72 InnerException: This bit of code throws a System.ArgumentException before the TypeInitializeException. It says: "Default value type does not match type of property Score": public static readonly DependencyProperty ScoreProperty = DependencyProperty.Register("Score", typeof(float), typeof(MainViewModel), new UIPropertyMetadata(0.0)); Here is the .NET property: public float Score { get { return (float) GetValue(ScoreProperty); } set { SetValue(ScoreProperty, value); } }

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  • Extract known pattern substring from NSString (without regex)

    - by d11wtq
    I'm really tempted to drop RegexKit (or my own libpcre wrapper) into my project in order to do this, but before I do that I want to know how Cocoa developers manage to do half of this basic stuff without really convoluted code or without linking with RegexKit or another regular expression library. I find it gobsmacking that Cocoa does not include any regular expression matching features. I've so accustomed to using regular expressions for all kinds of things that I'm lost without them. I can do what I need without them, but the code would be rather convoluted. So, Cocoa devs, I ask you, what's the "Cocoa way" to do this... The problem is an everyday problem in programming as far as I'm concerned. Cocoa must have ways of doing this with the built-in features. Note that the position of the elements I want to match changes, and sometimes "quotes" are present. Whitespace is variable. Take the following strings: Content-Type: application/xml; charset=utf-8 Content-Type: text/html; charset="iso-8859-1" Content-Type: text/plain; charset=us-ascii Content-Type: text/plain; name="example.txt"; charset=utf-8 From all of these strings, how would you go about determining the mime type (e.g. text/plain) and the charset (e.g. utf-8) using just the built-in Cocoa classes? I'd end up performing a series of -rangeOfString: and substring calls, with conditional checks to deal with the optional quotes etc. Is there a way to do this with NSScanner? The NSScanner class seems to have a pretty naive API to me. Something like C's sscanf() that works for NSString objects would be an ideal fit. Most of my string parsing needs are simple such as this example so maybe regular expressions, while I'm accustomed to them, are overkill?

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  • Preparing layout of web-design

    - by RPK
    I am starting design work of my first website. I know very little HTML. I don't know CSS and I am going to learn and use simultaneously. I want to know whether there is any tutorial on how to create a layout for any website. Any tips or best practices to be followed before designing starts?

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  • Silverlight Visual Studio XAML Design view not working

    - by Piyush
    I have installed visual studio 2008 sp1, silverlight tools, silverlight sdk, silverlight toolkit 2009 but still when I open silverlight application silverlight tools are not showing on my tool window as well as silverlight XAML Design view(color code formate) is not working. Whole xaml code is coming in black color.

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  • how does data clustering help in image or pattern recognition

    - by anon
    I have been playing around with different data clustering algorithms working on finding clusters between random data points represented an nodes, I keep reading that data clustering is used for image recognition. I am failing to make the connection, how does clustering data help in recognizing an image or in facial recognition. can someone explain this?

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  • Regex pattern failing

    - by Scott Chamberlain
    I am trying to strip out all things that are in a string that are not a letter number or space so I created the regex private static Regex _NonAlphaChars = new Regex("[^[A-Za-z0-9 ]]", RegexOptions.Compiled); however When I call _NonAlphaChars.Replace("Scott,", ""); it returns "Scott," What am I doing wrong that it is not matching the ,?

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