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• wxGraphicsContext dreadfully slow on Windows

  - by Jonatan

  I've implemented a plotter using wxGraphicsContext. The development was done using wxGTK, and the graphics was very fast. Then I switched to Windows (XP) using wxWidgets 2.9.0. And the same code is extremely slow. It takes about 350 ms to render a frame. Since the user is able to drag the plotter with the mouse to navigate it feels very sluggish with such a slow update rate. I've tried to implement some parts using wxDC and benchmarked the difference. With wxDC the code runs just about 100 times faster. As far as I know both Cairo and GDI+ are implemented in software at this point, so there's no real reason Cairo should be so much faster than GDI+. Am I doing something wrong? Or is the GDI+ implementation just not up on par with Cairo? One small note: I'm rendering to a wxBitmap now, with the wxGraphicsContext created from a wxMemoryDC. This is to avoid flicker on XP, since double buffering doesn't work there.

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• Is there any reason to use C instead of C++ for embedded development?

  - by Piotr Czapla

  Question I have two compilers on my hardware C++ and C89 I'm thinking about using C++ with classes but without polymorphism (to avoid vtables). The main reasons I’d like to use C++ are: I prefer to use “inline” functions instead of macro definitions. I’d like to use namespaces as I prefixes clutter the code. I see C++ a bit type safer mainly because of templates, and verbose casting. I really like overloaded functions and constructors (used for automatic casting). Do you see any reason to stick with C89 when developing for very limited hardware (4kb of RAM)? Conclusion Thank you for your answers, they were really helpful! I though the subject through and I will stick with C mainly because: It is easier to predict actual code in C and this is really important if you have only 4kb of ram. My team consists of C developers mainly so advance features of C++ won't be frequently used. I've found a way to inline functions in my C compiler (C89). It is hard to accept one answer as you provided so many good answers. Unfortunately I can't create a wiki and accept it so I will choose one answer that made me think most.

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• simplemodal - IE8 $.support.boxModel is not NULL and no object

  - by tom007

  Hi, I try to use the simplmodal script from: http://www.ericmmartin.com/projects/simplemodal/ I got this error $.support.boxModel is not NULL.. in IE8. jquery.simplemodal-1.3.4.min.js?F This is my implementation scipt.. what I have to change to avoid this error? function loadIframe(url){ $.modal('<iframe src="' + url + '" height="700px" width="600px" scrolling="no">', { containerCss:{ backgroundColor:"#fff", borderColor:"#333", }, overlayClose:true, opacity:70, overlayCss: { backgroundColor:"#000" }, onOpen: function (dialog) { dialog.overlay.fadeIn('slow', function () { dialog.container.toggleClass("preloader"); dialog.data.hide(); dialog.container.fadeIn('slow', function () { dialog.container.toggleClass("preloader"); dialog.data.slideDown('slow'); }); }); }, onClose: function (dialog) { dialog.data.fadeOut('slow', function () { dialog.container.slideUp('slow', function () { dialog.overlay.fadeOut('slow', function () { $.modal.close(); // must call this! }); }); }); } }); } $(document).ready(function(){ $("img").click(function(){ var baseurl = location.host; var url = $(this).attr("target"); var url = 'http://' + baseurl + url; loadIframe(url); }); });

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• MySql Query lag time?

  - by Click Upvote

  When there are multiple PHP scripts running in parallel, each making an UPDATE query to the same record in the same table repeatedly, is it possible for there to be a 'lag time' before the table is updated with each query? I have basically 5-6 instances of a PHP script running in parallel, having been launched via cron. Each script gets all the records in the items table, and then loops through them and processes them. However, to avoid processing the same item more than once, I store the id of the last item being processed in a seperate table. So this is how my code works: function getCurrentItem() { $sql = "SELECT currentItemId from settings"; $result = $this->db->query($sql); return $result->get('currentItemId'); } function setCurrentItem($id) { $sql = "UPDATE settings SET currentItemId='$id'"; $this->db->query($sql); } $currentItem = $this->getCurrentItem(); $sql = "SELECT * FROM items WHERE status='pending' AND id > $currentItem'"; $result = $this->db->query($sql); $items = $result->getAll(); foreach ($items as $i) { //Check if $i has been processed by a different instance of the script, and if so, //leave it untouched. if ($this->getCurrentItem() > $i->id) continue; $this->setCurrentItem($i->id); // Process the item here } But despite of all the precautions, most items are being processed more than once. Which makes me think that there is some lag time between the update queries being run by the PHP script, and when the database actually updates the record. Is it true? And if so, what other mechanism should I use to ensure that the PHP scripts always get only the latest currentItemId even when there are multiple scripts running in parrallel? Would using a text file instead of the db help?

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• P/Invoke declarations should not be safe-critical

  - by Bobrovsky

  My code imports following native methods: DeleteObject, GetFontData and SelectObject from gdi32.dll GetDC and ReleaseDC from user32.dll I want to run the code in full trust and medium trust environments (I am fine with exceptions being thrown when these imported methods are indirectly used in medium trust environments). When I run Code Analysis on the code I get warnings like: CA5122 P/Invoke declarations should not be safe-critical. P/Invoke method 'GdiFont.DeleteObject(IntPtr)' is marked safe-critical. Since P/Invokes may only be called by critical code, this declaration should either be marked as security critical, or have its annotation removed entirely to avoid being misleading. Could someone explain me (in layman terms) what does this warning really mean? I tried putting these imports in static SafeNativeMethods class as internal static methods but this doesn't make the warnings go away. I didn't try to put them in NativeMethods because after reading this article I am unsure that it's the right way to go because I don't want my code to be completely unusable in medium trust environments (I think this will be the consequence of moving imports to NativeMethods). Honestly, I am pretty much confused about the real meaning of the warning and consequences of different options to suppressing it. Could someone shed some light on all this? EDIT: My code target .NET 2.0 framework. Assembly is marked with [assembly: AllowPartiallyTrustedCallers] Methods are declared like this: [DllImport("gdi32")] internal static extern int DeleteObject(HANDLE hObject);

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• MYSQL - SELECT ALL FROM TABLE if...

  - by hornetbzz

  Hello I have a (nice) mysql table built like this : Fields Datas id (pk) 1 2 3 4 5 6 master_id 1000 1000 1000 2000 2000 2000 ... master_name home home home shop shop shop ... type_data value common client value common client ... param_a foo_a 1 0 bar_a 0 1 ... param_b foo_b 1 0 bar_b 1 0 ... param_c foo_c 0 1 bar_c 0 1 ... ... ... ... ... ... ... ... ... All these datas are embed in a single table. Each datas are dispatched on 3 "columns" set (1 for the values, 1 for identifying if these are common values and one for identifying client values). It's not the best I got but many other scripts depends on this structure. I'd need sthg like this: SELECT parameters name (eg param_a, param_b..) and their values (eg foo_a, foo_b..) WHEN master_id=? AND type_data=(common or client) (eg for values=1 on the 2nd column) . in order to get the parameters hash like param_a => foo_a param_b => foo_b param_c => foo_c ... I could not succeed in self joining on the same table till now but I guess it should be feasible. (I'd like to avoid to do several queries) Thx in advance

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• Android ListActivity with Bitmaps and Garbage Collection issue

  - by chis54

  I have a ListActivity and in it I set my list items with a class that extends SimpleCursorAdapter. I'm overriding bindView to set my Views. I have some TextViews and ImageViews. This is how I set my list items in my cursor adapter: String variableName = "drawable/q" + num + "_200px"; int imageResource = context.getResources().getIdentifier(variableName, "drawable", context.getPackageName()); if (imageResource != 0 ) { // The drawable exists Bitmap b = BitmapFactory.decodeResource(context.getResources(), imageResource); width = b.getWidth(); height = b.getHeight(); imageView.getLayoutParams().width = (int) (width); imageView.getLayoutParams().height = (int) (height); imageView.setImageResource(imageResource); } else { imageView.setImageResource(R.drawable.25trans_200px); } The problem I'm having is whenever I update my list with setListAdapter I get a large amount of garbage collection: D/dalvikvm(18637): GC_EXTERNAL_ALLOC freed 125K, 51% free 2710K/5447K, external 2022K/2137K, paused 75ms D/dalvikvm(18637): GC_EXTERNAL_ALLOC freed 30K, 51% free 2701K/5447K, external 2669K/2972K, paused 64ms D/dalvikvm(18637): GC_EXTERNAL_ALLOC freed 23K, 51% free 2713K/5447K, external 3479K/3579K, paused 53ms D/dalvikvm(18637): GC_EXTERNAL_ALLOC freed 22K, 51% free 2706K/5447K, external 3303K/3352K, paused 64ms D/dalvikvm(18637): GC_EXTERNAL_ALLOC freed 21K, 51% free 2722K/5447K, external 3569K/3685K, paused 102ms D/dalvikvm(18637): GC_EXTERNAL_ALLOC freed 23K, 50% free 2755K/5447K, external 3499K/3605K, paused 65ms D/dalvikvm(18637): GC_EXTERNAL_ALLOC freed 23K, 50% free 2771K/5447K, external 4213K/4488K, paused 53ms D/dalvikvm(18637): GC_EXTERNAL_ALLOC freed 18K, 49% free 2796K/5447K, external 5057K/5343K, paused 75ms D/dalvikvm(18637): GC_EXTERNAL_ALLOC freed 28K, 49% free 2803K/5447K, external 5944K/5976K, paused 53ms D/dalvikvm( 435): GC_EXPLICIT freed 6K, 54% free 2544K/5511K, external 1625K/2137K, paused 50ms D/dalvikvm( 165): GC_EXPLICIT freed 85K, 52% free 2946K/6087K, external 4838K/5980K, paused 111ms D/dalvikvm( 448): GC_EXPLICIT freed 1K, 54% free 2540K/5511K, external 1625K/2137K, paused 50ms D/dalvikvm( 294): GC_EXPLICIT freed 8K, 55% free 2598K/5703K, external 1625K/2137K, paused 64ms What can I do to avoid this? It's causing my UI to be sluggish and when I scroll, too.

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• HTML + CSS: fixed background image and body width/min-width (including fiddle)

  - by insertusernamehere

  So, here is my problem. I'm kinda stuck at the moment. I have a huge background image and content in the middle with those attributes: content is centered with margin auto and has a fixed width the content is related to the image (like the image is continued within the content) this relation is only horizontally (vertically scrolling moves everything around) This works actually fine (I'm only talking desktop, not mobile here :) ) with a position fixed on the huge background image. The problem that occurs is the following: When I resize the window to "smaller than the content" the background image gets it width from the body instead of the viewport. So the relation between content and image gets lost. Now I have this little JavaScript which does the trick, but this is of course some overhead I want to avoid: $(window).resize(function(){ img.css('left', (body.width() - img.width()) / 2 ); }); This works with a fixed positioned image, but can get a litty jumpy while calculating. I also tried things like that: <div id="test" style=" position: absolute; z-index: 0; top: 0; left: 0; width: 100%: height: 100%; background: transparent url(content/dummy/brand_backgroud_1600_1.jpg) no-repeat fixed center top; "></div> But this gets me back to my problem described. Is there any "script-less", elegant solution for this problem? UPDATE: now with Fiddle The one I'm trying to solve: http://jsfiddle.net/insertusernamehere/wPmrm/ The one with Javascript that works: http://jsfiddle.net/insertusernamehere/j5E8z/ NOTE The image size is always fixed. The image never gets scaled by the browser. In the JavaScript example it get's blown. So don't care about the size.

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• How to render an HTML attribute from a Razor view.

  - by ProfK

  I would like to use the same partial view for create, edit, and details views, to avoid duplicating the fieldset structure for an entity. Then, depending on which view renders the partial view, I would like to add a class of "read-only" to a div surrounding my fieldset and handle making the actual input fields read-only on the client, using css or jQuery, or whatever. How can I specify from my Razor view that I need this class added to the "item-details" div? <div class="item-details"> <fieldset> <legend>Product Details</legend> @Html.HiddenFor(model => model.DetailItem.ProductId) <div class="editor-label"> @Html.LabelFor(model => model.DetailItem.Name) </div> <div class="editor-field"> @Html.EditorFor(model => model.DetailItem.Name) @Html.ValidationMessageFor(model => model.DetailItem.Name) </div> <p> <input type="submit" value="Save" /> </p> </fieldset> </div>

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• can javascript process binary data?

  - by Johnny

  admit me describe my questions in situation-oriented way: assume IE is still the dominate web browser(the firefox have document for binary processing): the XMLHttpRequest.responseText or XMLHttpRequest.responseXML in ie desire txt or xml/xhtml/html,but what about the server response the xmlHttprequest whith MIME TYPE application/octet ? would the response string all little than 256 ?(every char of that string < 256), thanks very much for a straight answer, i have no webserver env,so i don't know how to test it out. because use txt or xml have a issue of character set encode, and i don't know how to process #[[[CDDATA node of one encoded xml(ex : utf-8,ascii,gb18030) with javascript, when i getNodeText, does the docObj return me byte or decoded char ? if it was decoded char which according to the header indicated charSet in the httpresponse , it would be all wrong. to avoid mess up with charSet ,i would like the server to response octet data and force strings data to be encoded as utf-8 but another charSet in the binary format. if the response is octal, so i guess the browser would not try to decode the response"txt" does this weird? or miss understanding the fundamental things? EDIT: I believe the question is asking this: Can Javascript safely process strings that aren't encoded in Unicode? What are the problems with trying to do so? EDIT: no no no , i means if http-header: content-type is "application/octet" , would the ie try to decoded it as (16bits Unicode | ie local setting charset ) when i get XMLHttpRequestobj.responseText use javascript ? or it(ie) just wrap every single byte of the response body as a javascript string, then every char in that string little than or equal 256 (char<=256), am i talking Mars language? sadly, if i were Marsizen,i would come as tourist without fuzzy questions. however i am in a country which share at least one property with Mars : RED

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• Strange layout behaviour

  - by andrii

  I am a little bit confused. Here is an small web page. There are two main div-s: top and mainBlock. First contain image. The problem is that firebug shows that div#top's height is equal to 0 and because of that the next div mainBlock moves up. If I would delete this peace of code: div#logo{ float: left; } everything will start working fine and div#mainBlock will be below the div#top. Could you, please, explain me how it works and how to avoid this in proper way? Here is my code: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/> <title>Paralab - Website &amp; interface design, web apps development, usability</title> <style text="text/css"> html, body{ } div#logo{ float: left; } #top{ width: 100%; } #mainBlock{ width:100%; } </style> </head> <body> <div id="top"> <div id="logo"> <img alt="logo" src="img/logo.png" /> </div> </div> <div id="mainBlock"> Contact Us </div> </body> </html>

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• GWT: Populating a page from datastore using RPC is too slow

  - by Ilya Boyandin

  Is there a way to speed up the population of a page with GWT's UI elements which are generated from data loaded from the datastore? Can I avoid making the unnecessary RPC call when the page is loaded? More details about the problem I am experiencing: There is a page on which I generate a table with names and buttons for a list of entities loaded from the datastore. There is an EntryPoint for the page and in its onModuleLoad() I do something like this: final FlexTable table = new FlexTable(); rpcAsyncService.getAllCandidates(new AsyncCallback<List<Candidate>>() { public void onSuccess(List<Candidate> candidates) { int row = 0; for (Candidate person : candidates) { table.setText(row, 0, person.getName()); table.setWidget(row, 1, new ToggleButton("Yes")); table.setWidget(row, 2, new ToggleButton("No")); row++; } } ... }); This works, but takes more than 30 seconds to load the page with buttons for 300 candidates. This is unacceptable. The app is running on Google App Engine and using the app engine's datastore.

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• how to use a parameterized function for the Default Binding of a Sql Server column

  - by Walt Gaber

  I have a table that catalogs selected files from multiple sources. I want to record whether a file is a duplicate of a previously cataloged file at the time the new file is cataloged. I have a column in my table (“primary_duplicate”) to record each entry as ‘P’ (primary) or ‘D’ (duplicate). I would like to provide a Default Binding for this column that would check for other occurrences of this file (i.e. name, length, timestamp) at the time the new file is being recorded. I have created a function that performs this check (see “GetPrimaryDuplicate” below). But I don’t know how to bind this function which requires three parameters to the table’s “primary_duplicate” column as its Default Binding. I would like to avoid using a trigger. I currently have a stored procedure used to insert new records that performs this check. But I would like to ensure that the flag is set correctly if an insert is performed outside of this stored procedure. How can I call this function with values from the row that is being inserted? USE [MyDatabase] GO SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE TABLE [dbo].[FileCatalog]( [id] [uniqueidentifier] NOT NULL, [catalog_timestamp] [datetime] NOT NULL, [primary_duplicate] nchar NOT NULL, [name] nvarchar NULL, [length] [bigint] NULL, [timestamp] [datetime] NULL ) ON [PRIMARY] GO ALTER TABLE [dbo].[FileCatalog] ADD CONSTRAINT [DF_FileCatalog_id] DEFAULT (newid()) FOR [id] GO ALTER TABLE [dbo].[FileCatalog] ADD CONSTRAINT [DF_FileCatalog_catalog_timestamp] DEFAULT (getdate()) FOR [catalog_timestamp] GO ALTER TABLE [dbo].[FileCatalog] ADD CONSTRAINT [DF_FileCatalog_primary_duplicate] DEFAULT (N'GetPrimaryDuplicate(name, length, timestamp)') FOR [primary_duplicate] GO USE [MyDatabase] GO SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE FUNCTION [dbo].[GetPrimaryDuplicate] ( @name nvarchar(255), @length bigint, @timestamp datetime ) RETURNS nchar(1) AS BEGIN DECLARE @c int SELECT @c = COUNT(*) FROM FileCatalog WHERE name=@name and length=@length and timestamp=@timestamp and primary_duplicate = 'P' IF @c > 0 RETURN 'D' -- Duplicate RETURN 'P' -- Primary END GO

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• Error when passing quotes to webservice by AJAX

  - by Radu

  I'm passing data using .ajax and here are my data and contentType attributes: data: '{ "UserInput" : "' + $('#txtInput').val() + '","Options" : { "Foo1":' + bar1 + ', "Foo2":' + Bar2 + ', "Flags":"' + flags + '", "Immunity":' + immunity + '}}', contentType: 'application/json; charset=utf-8', Server side my code looks like this: <WebMethod()> _ Public Shared Function ParseData(ByVal UserInput As String, ByVal Options As Options) As String The userinput is obvious but the Options structure is like the following: Public Structure Options Dim Foo1 As Boolean Dim Foo2 As Boolean Dim Flags As String Dim Immunity As Integer End Structure Everything works fine when $('#txtInput') contains no double-quotes but if they are present I get an error (for an input of asd"): {"Message":"Invalid object passed in, \u0027:\u0027 or \u0027}\u0027 expected. (22): { \"UserInput\" : \"asd\"\",\"Options\" : { \"Foo1\":false, \"Foo2\":false, \"Flags\":\"\", \"Immunity\":0}}","StackTrace":" at System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializeDictionary(Int32 depth)\r\n at System.Web.Script.Serialization.JavaScriptObjectDeserializer.DeserializeInternal(Int32 depth)\r\n at System.Web.Script.Serialization.JavaScriptObjectDeserializer.BasicDeserialize(String input, Int32 depthLimit, JavaScriptSerializer serializer)\r\n at System.Web.Script.Serialization.JavaScriptSerializer.Deserialize[T](String input)\r\n at System.Web.Script.Services.RestHandler.ExecuteWebServiceCall(HttpContext context, WebServiceMethodData methodData)","ExceptionType":"System.ArgumentException"} Any idea how I can avoid this error? Also, when I pass the same input with quotes directly it works fine.

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• Reordering methods in ComImport interfaces throws COMException (0x80041001)

  - by Ohad Schneider

  Consider the following code for COM interop with internet shortcuts: [ComImport] [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)] [Guid("CABB0DA0-DA57-11CF-9974-0020AFD79762")] public interface IUniformResourceLocatorW { void SetUrl([MarshalAs(UnmanagedType.LPWStr)] string pcszUrl, int dwInFlags); void GetUrl([MarshalAs(UnmanagedType.LPWStr)] out StringBuilder ppszUrl); void InvokeCommand(IntPtr purlici); } [ComImport] [Guid("FBF23B40-E3F0-101B-8488-00AA003E56F8")] public class InternetShortcut { } The following works as expected: var ishort = new InternetShortcut(); ((IPersistFile)ishort).Load("MyLink.url", 0); ((IUniformResourceLocatorW)ishort).GetUrl(out url); However: If I comment out IUniformResourceLocatorW.SetUrl (which I am not using), IUniformResourceLocatorW.GetUrl throws a COMException (HResult 0x80041001). If I switch between IUniformResourceLocatorW.SetUrl and IUniformResourceLocatorW.GetUrl (that is place the former below the latter) the same exception is thrown If I comment out IUniformResourceLocatorW.InvokeCommand the code runs fine. It's as if the order has to be preserved "up to" the invoked method. Is this behavior by design? documented somewhere? I'm asking because some COM interfaces are composed of many methods with possibly many supporting types and I'd rather avoid defining what I don't need if possible.

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• Tree data in MySql database table

  - by Robert Koritnik

  I have a table that uses Adjacency list model for hierarchy storage. My most relevant columns in this table are therefore: ItemId // is auto_increment ParentId Level ParentTrail // in the form of "parentId/../parentId/itemId" then I created a before insert tigger, that populates columns Level and ParentTrail. Since the last column also includes current item's ID I had to use a trick in my trigger because auto_increment columns are not available in the before insert trigger. So I get that value from the information_schema.tables table. All works fine, until I try to write an update trigger, that would update my item and its descendants when the item changes its parent (ParentId has changed). But I can't make an update on my table inside the update trigger. All I can do is to change current record's values but not other's. I could use a separate table for hierarchy data, but that would mean that I would also have to create a view that would combine these two tables (1:1 relation) and I would like to avoid this is at all possible. Is there a way to have all these in the same table so that these fields (Level and ParetTrail) set/update themselves automagically using triggers?

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• floating point equality in Python and in general

  - by eric.frederich

  I have a piece of code that behaves differently depending on whether I go through a dictionary to get conversion factors or whether I use them directly. The following piece of code will print 1.0 == 1.0 -> False But if you replace factors[units_from] with 10.0 and factors[units_to ] with 1.0 / 2.54 it will print 1.0 == 1.0 -> True #!/usr/bin/env python base = 'cm' factors = { 'cm' : 1.0, 'mm' : 10.0, 'm' : 0.01, 'km' : 1.0e-5, 'in' : 1.0 / 2.54, 'ft' : 1.0 / 2.54 / 12.0, 'yd' : 1.0 / 2.54 / 12.0 / 3.0, 'mile' : 1.0 / 2.54 / 12.0 / 5280, 'lightyear' : 1.0 / 2.54 / 12.0 / 5280 / 5.87849981e12, } # convert 25.4 mm to inches val = 25.4 units_from = 'mm' units_to = 'in' base_value = val / factors[units_from] ret = base_value * factors[units_to ] print ret, '==', 1.0, '->', ret == 1.0 Let me first say that I am pretty sure what is going on here. I have seen it before in C, just never in Python but since Python in implemented in C we're seeing it. I know that floating point numbers will change values going from a CPU register to cache and back. I know that comparing what should be two equal variables will return false if one of them was paged out while the other stayed resident in a register. Questions What is the best way to avoid problems like this?... In Python or in general. Am I doing something completely wrong? Side Note This is obviously part of a stripped down example but what I'm trying to do is come with with classes of length, volume, etc that can compare against other objects of the same class but with different units. Rhetorical Questions If this is a potentially dangerous problem since it makes programs behave in an undetermanistic matter, should compilers warn or error when they detect that you're checking equality of floats Should compilers support an option to replace all float equality checks with a 'close enough' function? Do compilers already do this and I just can't find the information.

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• Can I specify default value?

  - by atch

  Why is it that for user defined types when creating an array of objects every element of this array is initialized with default ctor but when I create built-in type this isn't the case? And second question: is it possible to specify default value to be used while initialize? Something like this (not valid): char* p = new char[size]('\0'); And another question in this topic while I'm with arrays. I suppose that when creating an array of user defined type and knowing the fact that every elem. of this array will be initialized with default value firstly why? If arrays for built in types do not initialize their elems. with their dflts why do they do it for UDT, and secondly: is there a way to switch it off/avoid/circumvent somehow? It seems like bit of a waste if I for example have created an array with size 10000 and then 10000 times dflt ctor will be invoked and I will (later on) overwrite this values anyway. I think that behaviour should be consistent, so either every type of array should be initialized or none. And I think that the behaviour for built-in arrays is more appropriate.

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• Android - Basic CRUD (REST/RPC client) to remote server

  - by bsreekanth

  There are lot of discussion about REST client implementation in android, based on the talk at GoogleIO 2010, by Virgil Dobjanschi. My requirement may not necessarily involved, as I have some freedom to choose the configuration. I only target tablets configuration changes can be prevented if no other easy way (fix at Landscape mode etc) I am trying to achieve. Basic CRUD operation to my server (JSON RPC/ REST). Basically mimic an ajax request from android app (no webview, need native app) Based on the above mentioned talk, and some reading I see these options. Implement any of the 3 mentioned in the Google IO talk Especially, the last pattern may be more suitable as I don't care much of caching. But not sure how "real time" is sync implementation. Use HTTP request in AsyncTask. Simplest, but need to avoid re-sending request during change in device configuration (orientation change etc). Even if I fix at one orientation, recreation of activity still happens. So need to handle it elegantly. Use service to handle http request. So far, it say use service for long ruiing request. Not sure whether it is a good approach for simple GET/POST/PUt requests. Please share your experience on what could be the best way.

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• Custom Silverlight Splash Screen causes White Screen of Death

  - by wickster05

  I'm developing a Silverlight 4 application and I've created a custom splash screen. At first glance, the custom splash screen worked well - really well. After a few days I started noticing that the splash screen would no longer show and the screen would remain blank. This seems to only occur when I open multiple IE tabs/windows all pointing to this same application. The first few will load fine, while the following tabs/windows will remain "white" - as if nothing has/is loaded. This doesn't appear to be an issue with other browsers that I've tested with (i.e., Firefox and Chrome). Unfortunately, this product requires multiple screens to be open (and I'm not going to require our users to use a non-Microsoft internet browser). Furthermore, we have another product that hosts this Silverlight application inside a WPF WebBrowser control (which is similar to IE - and experiences the same issues as delineated above). Does anyone have any ideas on how to get around this? This is becoming increasingly frustrating. I should also point out, that the default splash screen seems to avoid these issues. When I remove the custom splash screen, we no longer see these problems. ANY help would be appreciated greatly! -Tom

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• Instanced drawing with OpenGL ES 2.0

  - by Mårten Wikström

  In short: Is it possible to use the gl_InstanceID built-in variable in OpenGL ES 2.0? And, if so, how? Some more info: I want to draw multiple instances of an object using glDrawArraysInstanced and gl_InstanceID, and I want my application to run on multiple platforms, including iOS. The specification clearly says that these features require ES 3.0. According to the iOS Device Compatibility Reference ES 3.0 is only available on a few devices (those based on the A7 GPU; so iPhone 5s, but not on iPhone 5 or earlier). So my first assumption was that I needed to avoid using instanced drawing on older iOS devices. However, further down in the compatibility reference document it says that the EXT_draw_instanced extension is supported for all SGX Series 5 processors (that includes iPhone 5 and 4s). This makes me think that I could indeed use instanced drawing on older iOS devices too, by looking up and using the appropriate extension function (EXT or ARB) for glDrawArraysInstanced. I'm currently just running some test code using SDL and GLEW on Windows so I haven't tested anything on iOS yet. However, in my current setup I'm having trouble using the gl_InstanceID built-in variable in a vertex shader. I'm getting the following error message: 'gl_InstanceID' : variable is not available in current GLSL version Enabling the "draw_instanced" extension in GLSL has no effect: #extension GL_ARB_draw_instanced : enable #extension GL_EXT_draw_instanced : enable The error goes away when I specifically declare that I need ES 3.0 (GLSL 300 ES): #version 300 es Although that seem to work fine on my Windows desktop machine in an ES 2.0 context I doubt that this would work on an iPhone 5. So, shall I abandon the idea of being able to use instanced drawing on older iOS devices?

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• how to release object from thid party dll?

  - by Mohamed

  hi all, i'm developing a program to convert RTF to html i'm using the DLLs found here http://www.codeproject.com/KB/recipes/RtfConverter.aspx?fid=1458864&df=90&mpp=25&noise=3&sort=Position&view=Quick&select=3427424&fr=1#xx0xx this dll saves a jpg file from html to a specific folder, when i run the program, it cinverts the rtf for the first time and saves the images to the folder perfectly but when i try to convert it again i hace this error "error a generic error occured in GDI+" i think this dll use SaveImage method and to avoid this you must release the Image object you created but i can't modify the DLL, is there is any way to release the object i've created from this dll? this is my code RtfVisualImageAdapter imageAdapter = new RtfVisualImageAdapter( @Application.StartupPath + "\\Program Data\\temp\\{0}{1}", System.Drawing.Imaging.ImageFormat.Jpeg); RtfImageConvertSettings imageConvertSettings = new RtfImageConvertSettings(imageAdapter); RtfImageConverter imageConverter = new RtfImageConverter(imageConvertSettings); try { IRtfDocument rtfDocument = RtfInterpreterTool.BuildDoc( ConversionText, imageConverter); RtfHtmlConverter htmlConverter = new RtfHtmlConverter(rtfDocument); htmlConverter.Settings.ConvertVisualHyperlinks = true; htmlConverter.Settings.UseNonBreakingSpaces = true; this.richTextBoxPrintCtrl2.Text = htmlConverter.Convert(); } catch (Exception exception) { MessageBox.Show(this, "Error " + exception.Message, this.Text, MessageBoxButtons.OK, MessageBoxIcon.Error); }

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• Practical non-image based CAPTCHA approaches?

  - by Jeff Atwood

  It looks like we'll be adding CAPTCHA support to Stack Overflow. This is necessary to prevent bots, spammers, and other malicious scripted activity. We only want human beings to post or edit things here! We'll be using a JavaScript (jQuery) CAPTCHA as a first line of defense: http://docs.jquery.com/Tutorials:Safer_Contact_Forms_Without_CAPTCHAs The advantage of this approach is that, for most people, the CAPTCHA won't ever be visible! However, for people with JavaScript disabled, we still need a fallback and this is where it gets tricky. I have written a traditional CAPTCHA control for ASP.NET which we can re-use. However, I'd prefer to go with something textual to avoid the overhead of creating all these images on the server with each request. I've seen things like.. ASCII text captcha: \/\/(_)\/\/ math puzzles: what is 7 minus 3 times 2? trivia questions: what tastes better, a toad or a popsicle? Maybe I'm just tilting at windmills here, but I'd like to have a less resource intensive, non-image based <noscript> compatible CAPTCHA if possible. Ideas?

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• C++: is it safe to work with std::vectors as if they were arrays?

  - by peoro

  I need to have a fixed-size array of elements and to call on them functions that require to know about how they're placed in memory, in particular: functions like glVertexPointer, that needs to know where the vertices are, how distant they are one from the other and so on. In my case vertices would be members of the elements to store. to get the index of an element within this array, I'd prefer to avoid having an index field within my elements, but would rather play with pointers arithmetic (ie: index of Element *x will be x - & array[0]) -- btw, this sounds dirty to me: is it good practice or should I do something else? Is it safe to use std::vector for this? Something makes me think that an std::array would be more appropriate but: Constructor and destructor for my structure will be rarely called: I don't mind about such overhead. I'm going to set the std::vector capacity to size I need (the size that would use for an std::array, thus won't take any overhead due to sporadic reallocation. I don't mind a little space overhead for std::vector's internal structure. I could use the ability to resize the vector (or better: to have a size chosen during setup), and I think there's no way to do this with std::array, since its size is a template parameter (that's too bad: I could do that even with an old C-like array, just dynamically allocating it on the heap). If std::vector is fine for my purpose I'd like to know into details if it will have some runtime overhead with respect to std::array (or to a plain C array): I know that it'll call the default constructor for any element once I increase its size (but I guess this won't cost anything if my data has got an empty default constructor?), same for destructor. Anything else?

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• The perfect web UI framework (with Microsoft stack?) - architecture question?

  - by Igorek

  I'm looking for suggestions for the following issue, and I realize there is really not going to be a perfect answer to my question: I have a UI built in WinForms.NET (v4.0 framework) with WCF back-end and EF4 model objects, that I am looking to port to the web. UI is not huge and is not super complex and is structured well. But it is not a super simple system either. I am looking to pick a technology stack for the web-frontend that will target desktop & partially mobile platforms, provide a good development platform to build on, and facilitate code reuse across UI and back-end tiers... I would rather avoid: custom coding of UI-centric scripts, because they are hard to debug, non-compiled, usually a maintenance nightmare, almost always start to contain business logic, and duplicate some of the logic that back-end tiers have (especially validation) custom-coding for Desktop Web and Mobile Web UI's separately (although I realize that mobile web UI will likely contain fewer of data-entry screens and more reporting screens) non-.NET technology stacks I would love to: target the reporting capabilities of the system toward mobile web browsers not have to write a single line of script (javascript, jquery, etc.) utilize a good collection of controls that produces an elegant UI use .NET for everything The way I see it right now, I need to re-write this app in Silverlight, utilize a 3rd party UI framework like Telerik, and re-do the reports UI again for mobile platforms separately. However, I'm rather concerned about the shelf-life of Silverlight and the needed to deploy a different architecture to deal with mobile platform. Is there an ASP.NET/MVC/Ajax architecture/framework/library that would allow me to get at the power of .NET and without painful (imho) client-side scripting, while providing a decent user experience Thank you

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