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• How to minimize total cost of shortest path tree

  - by Michael

  I have a directed acyclic graph with positive edge-weights. It has a single source and a set of targets (vertices furthest from the source). I find the shortest paths from the source to each target. Some of these paths overlap. What I want is a shortest path tree which minimizes the total sum of weights over all edges. For example, consider two of the targets. Given all edge weights equal, if they share a single shortest path for most of their length, then that is preferable to two mostly non-overlapping shortest paths (fewer edges in the tree equals lower overall cost). Another example: two paths are non-overlapping for a small part of their length, with high cost for the non-overlapping paths, but low cost for the long shared path (low combined cost). On the other hand, two paths are non-overlapping for most of their length, with low costs for the non-overlapping paths, but high cost for the short shared path (also, low combined cost). There are many combinations. I want to find solutions with the lowest overall cost, given all the shortest paths from source to target. Does this ring any bells with anyone? Can anyone point me to relevant algorithms or analogous applications? Cheers!

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• Does NHibernate LINQ support ToLower() in Where() clauses?

  - by Daniel T.

  I have an entity and its mapping: public class Test { public virtual int Id { get; set; } public virtual string Name { get; set; } public virtual string Description { get; set; } } public class TestMap : EntityMap<Test> { public TestMap() { Id(x => x.Id); Map(x => x.Name); Map(x => x.Description); } } I'm trying to run a query on it (to grab it out of the database): var keyword = "test" // this is coming in from the user keyword = keyword.ToLower(); // convert it to all lower-case var results = session.Linq<Test> .Where(x => x.Name.ToLower().Contains(keyword)); results.Count(); // execute the query However, whenever I run this query, I get the following exception: Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index Am I right when I say that, currently, Linq to NHibernate does not support ToLower()? And if so, is there an alternative that allows me to search for a string in the middle of another string that Linq to NHibernate is compatible with? For example, if the user searches for kap, I need it to match Kapiolani, Makapuu, and Lapkap.

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• Get remote image using cURL then resample.

  - by Chris

  I want to be able to retrieve a remote image from a webserver, resample it, and then serve it up to the browser AND save it to a file. Here is what I have so far: $ch = curl_init(); // set URL and other appropriate options curl_setopt($ch, CURLOPT_URL, "$rURL"); curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); curl_setopt($ch, CURLOPT_HEADER, 0); // grab URL and pass it to the browser $out = curl_exec($ch); // close cURL resource, and free up system resources curl_close($ch); $imgRes = imagecreatefromstring($out); imagejpeg($imgRes, $filename, 70); header("Content-Type: image/jpg"); header("Content-length: ".filesize($filename)); header("Content-Transfer-Encoding: binary"); header("Content-Length: ".filesize($filename)); readfile("$filename"); exit(); Update Updated code to include imjpeg step to save the image as lower quality. But how do I then, efficiently, serve this up to the browser. I currently, later in the code, do this readfile("$filename"); along with some header information but that means I'm reading the file back in again which seems inefficient.

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• proper way to dynamically assign backbone.js view el

  - by kikuchiyo

  I would like to create two ( or more ) view instances, each with different el attributes, and have events bound to them via backbone.js view's events hash ( not through jQuery ). Getting events to trigger when all instantiations have the same el is easy: someView = Backbone.View.extend({ el: '#someDiv', events: { 'click': 'someFunction' }, someFunction: function(){ //Do something here } }); So far, if I assign el in the initialize function, and set events normally as follows, events do not trigger: someView = Backbone.View.extend({ events: { 'click': 'someFunction' }, initialize: function( options ){ this.el = options.el }, someFunction: function(){ //Do something here } }); My first instinct was to have el be a function that returns the string representation of the dom element of interest: someView = Backbone.View.extend({ el: function(){ return '#someDiv-' + this.someNumber }, events: { 'click': 'someFunction' }, initialize: function( options ){ this.someNumber = options.someNumber }, someFunction: function(){ //Do something here } }); However, this triggers someFunction x times if I have x instantiations of someView. Next I tried setting both the el and events attributes in initialize: someView = Backbone.View.extend({ initialize: function( options ){ this.el = options.el this.events = { 'click': 'someFunction' } }, someFunction: function(){ //Do something here } }); but this does not trigger events. At this point I'm pretty much fishing. Does anyone know how instantiate a backbone.js view with an el specific to that instance that has events that only trigger for that instance, and not other instances of the View?

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• Perl WordPress::XMLRPC categories not being set.

  - by Jay

  The following code works fine to upload a new post to a WordPress blog but for the life of me I can't seem to get the categories to be set. The categories exist. I've tried all lower case, tried case-matching, tried the slug version. Nothing works. No matter how I try passing the categories, the post gets assigned only to the default category. I've scoured the web to find other pieces of sample code and none mention the actual code semantics of how to assign post to certain categories using the WordPress::XMLRPC module. use WordPress::XMLRPC; my $o = WordPress::XMLRPC-new; $o-username('username'); $o-password('password'); $o-proxy('http://blogdomain.com/xmlrpc.php'); $o-server() || die "$!"; my $hashref = { 'title' = 'Test New Post 999 555456782', 'categories' = ['Categorie1', 'Categorie2'], 'description' = '<pHere is the content</p', 'mt_keywords' = 'tag1, tag2, tag3', 'mt_allow_comments' = 1, }; my $ID = $o-newPost($hashref, 1);

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• How to test if raising an event results in a method being called conditional on value of parameters

  - by MattC

  I'm trying to write a unit test that will raise an event on a mock object which my test class is bound to. What I'm keen to test though is that when my test class gets it's eventhandler called it should only call a method on certain values of the eventhandlers parameters. My test seems to pass even if I comment the code that calls ProcessPriceUpdate(price); I'm in VS2005 so no lambdas please :( So... public delegate void PriceUpdateEventHandler(decimal price); public interface IPriceInterface{ event PriceUpdateEventHandler PriceUpdate; } public class TestClass { IPriceInterface priceInterface = null; TestClass(IPriceInterface priceInterface) { this.priceInterface = priceInterface; } public void Init() { priceInterface.PriceUpdate += OnPriceUpdate; } public void OnPriceUpdate(decimal price) { if(price > 0) ProcessPriceUpdate(price); } public void ProcessPriceUpdate(decimal price) { //do something with price } } And my test so far :s public void PriceUpdateEvent() { MockRepository mock = new MockRepository(); IPriceInterface pi = mock.DynamicMock<IPriceInterface>(); TestClass test = new TestClass(pi); decimal prc = 1M; IEventRaiser raiser; using (mock.Record()) { pi.PriceUpdate += null; raiser = LastCall.IgnoreArguments().GetEventRaiser(); Expect.Call(delegate { test.ProcessPriceUpdate(prc); }).Repeat.Once(); } using (mock.Playback()) { test.Init(); raiser.Raise(prc); } }

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• storing/retrieving data for graph with long continuous stretches

  - by james

  i have a large 2-dimensional data set which i would like to graph. the graph is displayed in a browser and the data is retrieved via ajax. long stretches of this graph will be continuous - e.g., for x=0 through x=1000, y=9, then for x=1001 through x=1100, y=80, etc. the approach i'm considering is to send (from the server) and store (in the browser) only the points where the data changes. so for the example above, i would say data[0] = 9, then data[1001] = 80. then given x=999 for example, retrieving data[999] would actually look up data[0]. the problem that arises is finding a dictionary-like data structure which behaves like this. the approach i'm considering is to store the data in a traditional dictionary object, then also maintain a sorted array of key for that object. when given x=999, it would look at the mid-point of this array, determine whether the nearest lower key is left or right of that midpoint, then repeat with the correct subsection, etc.. does anyone have thoughts on this problem/approach?

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• Javascript: Whitespace Characters being Removed in Chrome (but not Firefox)

  - by Matrym

  Why would the below eliminate the whitespace around matched keyword text when replacing it with an anchor link? Note, this error only occurs in Chrome, and not firefox. For complete context, the file is located at: http://seox.org/lbp/lb-core.js To view the code in action (no errors found yet), the demo page is at http://seox.org/test.html. Copy/Pasting the first paragraph into a rich text editor (ie: dreamweaver, or gmail with rich text editor turned on) will reveal the problem, with words bunched together. Pasting it into a plain text editor will not. // Find page text (not in links) -> doxdesk.com function findPlainTextExceptInLinks(element, substring, callback) { for (var childi= element.childNodes.length; childi-->0;) { var child= element.childNodes[childi]; if (child.nodeType===1) { if (child.tagName.toLowerCase()!=='a') findPlainTextExceptInLinks(child, substring, callback); } else if (child.nodeType===3) { var index= child.data.length; while (true) { index= child.data.lastIndexOf(substring, index); if (index===-1 || limit.indexOf(substring.toLowerCase()) !== -1) break; // don't match an alphanumeric char var dontMatch =/\w/; if(child.nodeValue.charAt(index - 1).match(dontMatch) || child.nodeValue.charAt(index+keyword.length).match(dontMatch)) break; // alert(child.nodeValue.charAt(index+keyword.length + 1)); callback.call(window, child, index) } } } } // Linkup function, call with various type cases (below) function linkup(node, index) { node.splitText(index+keyword.length); var a= document.createElement('a'); a.href= linkUrl; a.appendChild(node.splitText(index)); node.parentNode.insertBefore(a, node.nextSibling); limit.push(keyword.toLowerCase()); // Add the keyword to memory urlMemory.push(linkUrl); // Add the url to memory } // lower case (already applied) findPlainTextExceptInLinks(lbp.vrs.holder, keyword, linkup); Thanks in advance for your help. I'm nearly ready to launch the script, and will gladly comment in kudos to you for your assistance.

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• File transfer eating alot of CPU

  - by Dan C.

  I'm trying to transfer a file over a IHttpHandler, the code is pretty simple. However when i start a single transfer it uses about 20% of the CPU. If i were to scale this to 20 simultaneous transfers the CPU is very high. Is there a better way I can be doing this to keep the CPU lower? the client code just sends over chunks of the file 64KB at a time. public void ProcessRequest(HttpContext context) { if (context.Request.Params["secretKey"] == null) { } else { accessCode = context.Request.Params["secretKey"].ToString(); } if (accessCode == "test") { string fileName = context.Request.Params["fileName"].ToString(); byte[] buffer = Convert.FromBase64String(context.Request.Form["data"]); string fileGuid = context.Request.Params["smGuid"].ToString(); string user = context.Request.Params["user"].ToString(); SaveFile(fileName, buffer, user); } } public void SaveFile(string fileName, byte[] buffer, string user) { string DirPath = @"E:\Filestorage\" + user + @"\"; if (!Directory.Exists(DirPath)) { Directory.CreateDirectory(DirPath); } string FilePath = @"E:\Filestorage\" + user + @"\" + fileName; FileStream writer = new FileStream(FilePath, File.Exists(FilePath) ? FileMode.Append : FileMode.Create, FileAccess.Write, FileShare.ReadWrite); writer.Write(buffer, 0, buffer.Length); writer.Close(); }

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• Are there any prototype-based languages with a whole development cycle?

  - by Kaveh Shahbazian

  Are there any real-world prototype-based programming languages with a whole development cycle? "A whole development cycle" like Ruby and Python: web frameworks, scripting/interacting with the system, tools for debugging, profiling, etc. Thank you A brief note on PBPLs: (let's call these languages PBPL : prototype-based programming language) There are some PBPLs out there. Some are being widely used like JavaScript (which Node.js may bring it into the field - or may not!). One other language is ActionScript which is also a PBPL but tightly bound to Flash VM (is it correct to say so?). From less known ones I can speak of Lua which has a strong reputation in game development (mostly spread by WOW) but never took off as a full language. Lua has a table concept which can provide you some sort of prototype based programming facility. There is also JScript (Windows scripting tool) which is already pointless by the newcomer PowerShell (I have used JScript to manipulate IIS but I never understood what is JScript!). Others can be named like io (indeed very very neat, you will fall in love with it; absolutely impossible to use) and REBOL (What is this all about? A proprietary scripting tool? You must be kidding!) and newLISP (Which is actually a full language, but no one ever heard about it). For sure there are much more to list here but either I do not remember or I did not understood them as a real world thing, like Self).

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• What framework would allow for the largest coverage of freelance developers in the media/digital mar

  - by optician

  This question is not about which is the best, it is about which makes the most business sense to use as a company's platform of choice for ongoing freelance development. I'm currently trying to decide what framework to move my company in regarding frameworks for web application work. Options are ASP.NET MVC Django CakePHP/Symfony etc.. Struts Pearl on Rails Please feel free to add more to the discussion. I currently work in ASP.NET MVC in my Spare time, and find it incredibly enjoyable to work with. It is my first experince with an MVC framework for the web, so I can't talk on the others. The reason for not pushing this at the company is that I feel that there are not many developers in the Media/Marketing world who would work with this, so it may be hard to extend the team, or at least cost more. I would like to move into learning and pushing Django, partly to learn python, partly to feel a bit cooler (all my geeky friends use Java/Python/c++). Microsoft is the dark side to most company's I work with (Marketing/Media focused). But again I'm worried about developers in this sector. PHP seems like the natural choice, but I'm scared by the sheer amount of possible frameworks, and also that the quality of developer may be lower. I know there are great php developers out there, but how many of them know multiple frameworks? Are they similar enough that anyone decent at php can pick them up? Just put struts in the list as an option, but personally I live with a Java developer, and considering my experience with c#, I'm just not that interested in learning Java (selfish personal geeky reasons) Final option was a joke http://www.bbc.co.uk/blogs/radiolabs/2007/11/perl_on_rails.shtml

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• How to recursive rake? -- or suitable alternatives

  - by TerryP

  I want my projects top level Rakefile to build things using rakefiles deeper in the tree; i.e. the top level rakefile says how to build the project (big picture) and the lower level ones build a specific module (local picture). There is of course a shared set of configuration for the minute details of doing that whenever it can be shared between tasks: so it is mostly about keeping the descriptions of what needs building, as close to the sources being built. E.g. /Source/Module/code.foo and cie should be built using the instructions in /Source/Module/Rakefile; and /Rakefile understands the dependencies between modules. I don't care if it uses multiple rake processes (ala recursive make), or just creates separate build environments. Either way it should be self-containable enough to be processed by a queue: so that non-dependent modules could be built simultaneously. The problem is, how the heck do you actually do something like that with Rake!? I haven't been able to find anything meaningful on the Internet, nor in the documentation. I tried creating a new Rake::Application object and setting it up, but whatever methods I try invoking, only exceptions or "Don't know how to build task ':default'" errors get thrown. (Yes, all rakefiles have a :default). Obviously one could just execute 'rake' in a sub directory for a :modulename task, but that would ditch the options given to the top level; e.g. think of $(MAKE) and $(MAKEFLAGS). Anyone have a clue on how to properly do something like a recursive rake?

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• How to define index by several columns in hibernate entity?

  - by foobar

  Morning. I need to add indexing in hibernate entity. As I know it is possible to do using @Index annotation to specify index for separate column but I need an index for several fields of entity. I've googled and found jboss annotation @Table, that allows to do this (by specification). But (I don't know why) this functionality doesn't work. May be jboss version is lower than necessary, or maybe I don't understant how to use this annotation, but... complex index is not created. Why index may not be created? jboss version 4.2.3.GA Entity example: package somepackage; import org.hibernate.annotations.Index; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; @Entity @org.hibernate.annotations.Table(appliesTo = House.TABLE_NAME, indexes = { @Index(name = "IDX_XDN_DFN", columnNames = {House.XDN, House.DFN} ) } ) public class House { public final static String TABLE_NAME = "house"; public final static String XDN = "xdn"; public final static String DFN = "dfn"; @Id @GeneratedValue private long Id; @Column(name = XDN) private long xdn; @Column(name = DFN) private long dfn; @Column private String address; public long getId() { return Id; } public void setId(long id) { this.Id = id; } public long getXdn() { return xdn; } public void setXdn(long xdn) { this.xdn = xdn; } public long getDfn() { return dfn; } public void setDfn(long dfn) { this.dfn = dfn; } public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } } When jboss/hibernate tries to create table "house" it throws following exception: Reason: org.hibernate.AnnotationException: @org.hibernate.annotations.Table references an unknown table: house

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• Prevent deferred creation of controls.

  - by Scott Chamberlain

  Here is a test framework to show what I am doing, just create a new project add a tabbed control, on tab 1 put a button on tab 2 put a check box (default names) and paste this code for its code public partial class Form1 : Form { private List<bool> boolList = new List<bool>(); BindingSource bs = new BindingSource(); public Form1() { InitializeComponent(); boolList.Add(false); bs.DataSource = boolList; checkBox1.DataBindings.Add("Checked", bs, ""); } bool updating = false; private void button1_Click(object sender, EventArgs e) { updating = true; boolList[0] = true; bs.ResetBindings(false); Application.DoEvents(); updating = false; } private void checkBox1_CheckedChanged(object sender, EventArgs e) { if (!updating) MessageBox.Show("CheckChanged fired outside of updating"); } } The issue is if you run the program and look at tab 2 then press the button on tab 1 the program works as expected, however if you press the button on tab 1 then look at tab 2 the event for the checkbox will not fire untill you look at tab 2. The reason for this is the controll on tab 2 is not in the "created" state, so its binding to change the checkbox from unchecked to checked does not happen until after the control has been "Created". checkbox1.CreateControl() does not do anything because according to MSDN CreateControl does not create a control handle if the control's Visible property is false. You can either call the CreateHandle method or access the Handle property to create the control's handle regardless of the control's visibility, but in this case, no window handles are created for the control's children. I tried getting the value of Handle(there is no CreateHandle for Button) but still the same result. Any suggestions other than have the program quickly flash all of my tabs that have data-bound check boxes when it first loads?

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• How can a program be detected as running?

  - by ryeguy

  I have written a program that is sort of an unofficial, standalone plugin for an application. It allows customers to get a service that is a lower priced alternative then the vendor-owned one. My program is not illegal, against any kind of TOS, and is certainly not a virus, adware, or anything like that. That being said, the vendor of course is not happy about me taking his competition, and is trying to block my application from running. He has already tried some tactics to stop people from running my app alongside his. He makes it so if it is detected, his app throws a fake error. First, he checked to see if my program was running by looking for an open window with the right title. I countered this by randomizing the program title at startup. Next, he looked for the running process name. I countered this by making the app copy itself when it is started as [random string].exe and then running that. Anyways, my question is this: what else can he do to detect if my program running? I know that you can read window text (ie status bar, labels). I'm prepared to counter this by replacing the labels with images (ugh, any other way?). But what else is there? Can you detect what .dlls a program has loaded? If so, could this be solved by randomizing the dll names before loading them? I know that it's possible to get a program's signature in memory and track it that way (like a virus scanner), but the chances of him doing that probably aren't good because that sounds pretty advanced. Even though this is kinda crappy of him to be doing, its kind of fun. It's like a nerdy fist fight. EDIT: When I said it's a plugin, that is just the (incorrect) term I used. It's a standalone EXE. The "API" between my program and the other is mine is simply entering data into the controls (like textboxes, etc).

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• CreateDelegate with unknown types

  - by Giorgi

  Hello, I am trying to create Delegate for reading/writing properties of unknown type of class at runtime. I have a generic class Main<T> and a method which looks like this: Delegate.CreateDelegate(typeof(Func<T, object>), get) where get is a MethodInfo of the property that should be read. The problem is that when the property returns int (I guess this happens for value types) the above code throws ArgumentException because the method cannot be bound. In case of string it works well. To solve the problem I changed the code so that corresponding Delegate type is generated by using MakeGenericType. So now the code is: Type func = typeof(Func<,>); Type generic = func.MakeGenericType(typeof(T), get.ReturnType); var result = Delegate.CreateDelegate(generic, get) The problem now is that the created delegate instance of generic so I have to use DynamicInvoke which would be as slow as using pure reflection to read the field. So my question is why is that the first snippet of code fails with value types. According to MSDN it should work as it says that The return type of a delegate is compatible with the return type of a method if the return type of the method is more restrictive than the return type of the delegate and how to execute the delegate in the second snippet so that it is faster than reflection. Thanks.

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• Binding event handlers to specific elements, using bubbling (JavaScript/jQuery)

  - by Bungle

  I'm working on a project that approximates the functionality of Firebug's inspector tool. That is, when mousing over elements on the page, I'd like to highlight them (by changing their background color), and when they're clicked, I'd like to execute a function that builds a CSS selector that can be used to identify them. However, I've been running into problems related to event bubbling, and have thoroughly confused myself. Rather than walk you down that path, it might make sense just to explain what I'm trying to do and ask for some help getting started. Here are some specs: I'm only interested in elements that contain a text node (or any descendant elements with text nodes). When the mouse enters such an element, change its background color. When the mouse leaves that element, change its background color back to what it was originally. When an element is clicked, execute a function that builds a CSS selector for that element. I don't want a mouseover on an element's margin area to count as a mouseover for that element, but for the element beneath (I think that's default browser behavior anyway?). I can handle the code that highlights/unhighlights, and builds the CSS selector. What I'm primarily having trouble with is efficiently binding event handlers to the elements that I want to be highlightable/clickable, and avoiding/stopping bubbling so that mousing over a (<p>) element doesn't also execute the handler function on the <body>, for example. I think the right way to do this is to bind event handlers to the document element, then somehow use bubbling to only execute the bound function on the topmost element, but I don't have any idea what that code looks like, and that's really where I could use help. I'm using jQuery, and would like to rely on that as much as possible. Thanks in advance for any guidance!

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• How do I change the CellErrorStyle for an Xceed Datagrid?

  - by Bob

  So in the Xceed documentation there is a code example that does not work for me. It may be because my grid is bound to a DataGridCollectionView. The objects in the collection used by the datagridcollection are what implement IDataErrorInfo. The errors are showing up just fine. The problem is that they are using the default orange background for errors...I need a red border. Below is the XAML instantiation of my grid. I set the DataCell background property to red just so I could be sure I had access to the grid's properties... I do. I just can't find the way to identify the cell's w/ errors so I can style them. Thanks! <XceedDG:DataGridControl Grid.Row="1" Grid.ColumnSpan="5" ItemsSource="{Binding Path = ABGDataGridCollectionView, UpdateSourceTrigger=PropertyChanged}" Background="{x:Static Views:DataGridControlBackgroundBrushes.ElementalBlue}" IsDeleteCommandEnabled="True" FontSize="16" AutoCreateColumns="False" x:Name="EncounterDataGrid" AllowDrop="True"> <XceedDG:DataGridControl.View> <Views:TableView ColumnStretchMode="All" ShowRowSelectorPane="True" ColumnStretchMinWidth="100"> <Views:TableView.FixedHeaders> <DataTemplate> <XceedDG:InsertionRow Height="40"/> </DataTemplate> </Views:TableView.FixedHeaders> </Views:TableView> </XceedDG:DataGridControl.View> <!--Group Header formatting--> <XceedDG:DataGridControl.Resources> <Style TargetType="{x:Type XceedDG:GroupByControl}"> <Setter Property="Visibility" Value="Collapsed"/> </Style> <Style TargetType="{x:Type XceedDG:DataCell}"> <Setter Property="Background" Value="Red"/> </Style> </XceedDG:DataGridControl.Resources> ...

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• Finding a picture in a picture with java?

  - by tarrasch

  what i want to to is analyse input from screen in form of pictures. I want to be able to identify a part of an image in a bigger image and get its coordinates within the bigger picture. Example: would have to be located in And the result would be the upper right corner of the picture in the big picture and the lower left of the part in the big picture. As you can see, the white part of the picture is irrelevant, what i basically need is just the green frame. Is there a library that can do something like this for me? Runtime is not really an issue. What i want to do with this is just generating a few random pixel coordinates and recognize the color in the big picture at that position, to recognize the green box fast later. And how would it decrease performance, if the white box in the middle is transparent? The question has been asked several times on SO as it seems without a single answer. I found i found a solution at http://werner.yellowcouch.org/Papers/subimg/index.html . Unfortunately its in C++ and i do not understand a thing. Would be nice to have a Java implementation on SO.

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• How Can I: Generate 40/64 Bit WEP Key In Python?

  - by Aktariel

  So, I've been beating my head against the wall of this issue for several months now, partly because it's a side interest and partly because I suck at programming. I've searched and researched all across the web, but have not had any luck (except one small bit of success; see below), so I thought I might try asking the experts. What I am trying to do is, as the title suggests, generate a 40/64 bit WEP key from a passphrase, according to the "de facto" standard. (A site such as [http://www.powerdog.com/wepkey.cgi] produces the expected outputs.) I have already written portions of the script that take inputs and write them to a file; one of the inputs would be the passphrase, sanitized to lower case. For the longest time I had no idea what the defacto standard was, much less how to even go about implementing it. I finally stumbled across a paper (http://www.lava.net/~newsham/wlan/WEP_password_cracker.pdf) that sheds as much light as I've had yet on the issue (page 18 has the relevant bits). Apparently, the passphrase is "mapped to a 32-bit value with XOR," the result of which is then used as the seed for a "linear congruential PRNG (which one of the several PRNGs Python has would fit this description, I don't know), and then from that result several bits of the result are taken. I have no idea how to go about implementing this, since the description is rather vague. What I need is help in writing the generator in Python, and also in understanding how exactly the key is generated. I'm not much of a programmer, so explanations are appreciated as well. (Yes, I know that WEP isn't secure.)

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• WPF In-Memory Image Display

  - by Aren B

  Im trying to build an Item Template for my list-view and im bound to a list of Entities. The entity I have has a System.Drawing.Image that I'd like to display, but so far I cannot for the life of me figure out how to bind it to the <Image> block. Every example and documentation I can find on the internet pertains to Images accessible via an uri i.e. File on HDD or On Website <DataTemplate x:Key="LogoPreviewItem"> <Border BorderBrush="Black" BorderThickness="1"> <DockPanel Width="150" Height="100"> <Image> <Image.Source> <!-- {Binding PreviewImage} is where the System.Drawing.Image is in this context --> </Image.Source> </Image> <Label DockPanel.Dock="Bottom" Content="{Binding CustomerName}" /> </DockPanel> </Border> </DataTemplate>

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• Linq duplicate removal with a twist

  - by Danthar

  I got a list that contains al the status items of each order. The problem that i have is that i need to remove all the items of which the status - logdate combination is not the highest. e.g var inputs = new List<StatusItem>(); //note that the 3th id is simply a modifier that adds that amount of secs //to the current datetime, to make testing easier inputs.Add(new StatusItem(123, 30, 1)); inputs.Add(new StatusItem(123, 40, 2)); inputs.Add(new StatusItem(123, 50, 3)); inputs.Add(new StatusItem(123, 40, 4)); inputs.Add(new StatusItem(123, 50, 5)); inputs.Add(new StatusItem(100, 20, 6)); inputs.Add(new StatusItem(100, 30, 7)); inputs.Add(new StatusItem(100, 20, 8)); inputs.Add(new StatusItem(100, 30, 9)); inputs.Add(new StatusItem(100, 40, 10)); inputs.Add(new StatusItem(100, 50, 11)); inputs.Add(new StatusItem(100, 40, 12)); var l = from i in inputs group i by i.internalId into cg select from s in cg group s by s.statusId into sg select sg.OrderByDescending(n => n.date).First() ; This creates a list that returnes me the following: order 123 status 30 date 4/9/2010 6:44:21 PM order 123 status 40 date 4/9/2010 6:44:24 PM order 123 status 50 date 4/9/2010 6:44:25 PM order 100 status 20 date 4/9/2010 6:44:28 PM order 100 status 30 date 4/9/2010 6:44:29 PM order 100 status 40 date 4/9/2010 6:44:32 PM order 100 status 50 date 4/9/2010 6:44:31 PM This is ALMOST correct. However that last line which has status 50 needs to be filtered out as well because it was overruled by status 40 in the historylist. U can tell by the fact that its date is lower then the "last" status-item with the status 40. I was hoping someone could give me some pointers because im stuck.

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• Window message procedures in Linux vs Windows

  - by mizipzor

  In Windows when you create a window, you must define a (c++) LRESULT CALLBACK message_proc(HWND Handle, UINT Message, WPARAM WParam, LPARAM LParam); to handle all the messages sent from the OS to the window, like keypresses and such. Im looking to do some reading on how the same system works in Linux. Maybe it is because I fall a bit short on the terminology but I fail to find anything on this through google (although Im sure there must be plenty!). Is it still just one single C function that handles all the communication? Does the function definition differ on different WMs (Gnome, KDE) or is it handled on a lower level in the OS? Edit: Ive looked into tools like QT and WxWidgets, but those frameworks seems to be geared more towards developing GUI extensive applications. Im rather looking for a way to create a basic window (restrict resize, borders/decorations) for my OGL graphics and retrieve input on more than one platform. And according to my initial research, this kind of function is the only way to retrieve that input. What would be the best route? Reading up, learning and then use QT or WxWidgets? Or learning how the systems work and implement those few basic features I want myself?

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• Delphi 6 OleServer.pas Invoke memory leak

  - by Mike Davis

  There's a bug in delphi 6 which you can find some reference online for when you import a tlb the order of the parameters in an event invocation is reversed. It is reversed once in the imported header and once in TServerEventDIspatch.Invoke. you can find more information about it here: http://cc.embarcadero.com/Item/16496 somewhat related to this issue there appears to be a memory leak in TServerEventDispatch.Invoke with a parameter of a Variant of type Var_Array (maybe others, but this is the more obvious one i could see). The invoke code copies the args into a VarArray to be passed to the event handler and then copies the VarArray back to the args after the call, relevant code pasted below: // Set our array to appropriate length SetLength(VarArray, ParamCount); // Copy over data for I := Low(VarArray) to High(VarArray) do VarArray[I] := OleVariant(TDispParams(Params).rgvarg^[I]); // Invoke Server proxy class if FServer <> nil then FServer.InvokeEvent(DispID, VarArray); // Copy data back for I := Low(VarArray) to High(VarArray) do OleVariant(TDispParams(Params).rgvarg^[I]) := VarArray[I]; // Clean array SetLength(VarArray, 0); There are some obvious work-arounds in my case: if i skip the copying back in case of a VarArray parameter it fixes the leak. to not change the functionality i thought i should copy the data in the array instead of the variant back to the params but that can get complicated since it can hold other variants and seems to me that would need to be done recursively. Since a change in OleServer will have a ripple effect i want to make sure my change here is strictly correct. can anyone shed some light on exactly why memory is being leaked here? I can't seem to look up the callstack any lower than TServerEventDIspatch.Invoke (why is that?) I imagine that in the process of copying the Variant holding the VarArray back to the param list it added a reference to the array thus not allowing it to be release as normal but that's just a rough guess and i can't track down the code to back it up. Maybe someone with a better understanding of all this could shed some light?

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• .NET Remoting switching channels by itself.

  - by Casper

  Hi. We are having an odd problem with .NET Remoting. Basically, we have a server which registers two TcpChannels with ChannelServices.RegisterChannel(): one listens on port 50000, the other one listens on port 15000. We then have a client that registers a TcpChannel to be able to communicate with the server. We retrieve a an object from the server by calling Activator.GetObject() with the URI "tcp://serverip:50000/objectname" and this works fine, the client connects to the server on port 50000 and gets the object. However, when we start calling methods on that object, the connection to the channel on port 50000 is dropped, and a new connection is made to the channel on port 15000 automatically. This poses a real problem for us since we don't want traffic on port 15000 because that channel may not be bound to the same network adapter as the port 50000 channel on the server or that port may not be open in the firewall, which causes the remoting calls to fail naturally. This is very strange to us since the client has no knowledge in our code that there exists another channel on the server on port 15000 or what IP it listens on, yet it attempt to connect to it. Any help on this is greatly appreciated, /Casper c

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