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  • How to work with BufferedImage and YCbCr colorspace?

    - by Onlyx
    Hi everyone! I need to translate colors in bitmap loaded to BufferedImage from RGB to YCbCr (luminance and 2 channels chrominance) and back after process. I made it with functions used like rgb2ycbcr() in main method for each pixel, but it isn't so smart solution. I should use ColorSpace and ColorModel classes to get BufferedImage with correct color space. It would be more flexible method, but I don't know how to do that. I'm lost and I need some tips. Can somebody help me?

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  • Screen Capture with Open GL using glReadPixels

    - by Raja
    Hi, I created a CGRegisterScreenRefreshCallback(refreshCallback, NULL) and in the refreshCallback method get the list of rectangles which have changed. I am getting the rectangle data from frameBuffer using OpenGL glReadPixels. Is there a better way of screen capture either with/without opengl and also using OpenGL can I skip reading pixel by pixel ? I have looked at glGetTexImage and glCopyTexSubImage2D. Any simple code block which can explain how to use these functions to get the changed rectangle data would be very helpful ? Thanks, Raja.

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  • How should I rewrite my code to make it amenable to unittesting?

    - by justin
    I've been trying to get started with unit-testing while working on a little cli program. My program basically parses the command line arguments and options, and decides which function to call. Each of the functions performs some operation on a database. So, for instance, I might have a create function: def create(self, opts, args): #I've left out the error handling. strtime = datetime.datetime.now().strftime("%D %H:%M") vals = (strtime, opts.message, opts.keywords, False) self.execute("insert into mytable values (?, ?, ?, ?)", vals) self.commit() Should my test case call this function, then execute the select sql to check that the row was entered? That sounds reasonable, but also makes the tests more difficult to maintain. Would you rewrite the function to return something and check for the return value? Thanks

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  • What tools are people using to measure SQL Server database performance?

    - by Paul McLoughlin
    I've experimented with a number of techniques for monitoring the health of our SQL Servers, ranging from using the Management Data Warehouse functionality built into SQL Server 2008, through other commercial products such as Confio Ignite 8 and also of course rolling my own solution using perfmon, performance counters and collecting of various information from the dynamic management views and functions. What I am finding is that whilst each of these approaches has its own associated strengths, they all have associated weaknesses too. I feel that to actually get people within the organisation to take the monitoring of SQL Server performance seriously whatever solution we roll out has to be very simple and quick to use, must provide some form of a dashboard, and the act of monitoring must have minimal impact on the production databases (and perhaps even more importantly, it must be possible to prove that this is the case). So I'm interested to hear what others are using for this task? Any recommendations?

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  • Does a version control database storage engine exist?

    - by Zak
    I was just wondering if a storage engine type existed that allowed you to do version control on row level contents. For instance, if I have a simple table with ID, name, value, and ID is the PK, I could see that row 354 started as (354, "zak", "test")v1 then was updated to be (354, "zak", "this is version 2 of the value")v2 , and could see a change history on the row with something like select history (value) where ID = 354. It's kind of an esoteric thing, but it would beat having to keep writing these separate history tables and functions every time a change is made...

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  • jQuery autocomplete function, how to add support for words not available in the database yet?

    - by Lyon
    Hi, I'm looking to implement a tag system like how SO uses on their site, where users can specify multiple tag words. However, on top of all the other autocomplete functions available as jquery plugins, I also want to allow users to enter new words not in the database. Does anyone know of any plugin that can do that? Or if there isn't, how one can add that functionality to an existing autocomplete function? I'm exploring Drew Wilson's autosuggest plugin at the moment, as it supports multiple tags well: http://code.drewwilson.com/entry/autosuggest-jquery-plugin Any help appreciated! Thanks :)

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  • Loading Youtube Iframe API with RequireJS

    - by davidgnin
    I'm trying to use the Youtube Iframe API inside a module definded with Require JS. As this API is loaded async and calls a function once is loaded, I used a requireJS plugin called "async", that worked before with google maps api. However, this time something isn't working. My module starts this way: define(['text!fmwk/widgets/video/video.html','fmwk/utils/browser','async!http://www.youtube.com/iframe_api'], function (videoTpl,root) { ... }); and chrome console fires this error: Uncaught Error: Load timeout for modules: async!http://www.youtube.com/iframe_api_unnormalized3,async!http://www.youtube.com/iframe_api http://requirejs.org/docs/errors.html#timeout If I don't use async plugin the object YT or its functions are undefinded, and the same happens if I download the API code. The API is loaded sometimes if I put an script tag in the head tag of the html file. All this is expected, but I don't understand because async plugin fails. Thank you for your attention and help :)

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  • Creating a child process on Unix systems?

    - by Hakan Svensson
    I'm trying to create a child process in another process. I am writing both the programs in C language. First I write a dummy process which will be the child process. What it is doing is only to write a string on the screen. It works well on its own. Then I write another program which will be the parent process. However, I can't make it happen. I'm trying to use fork and execl functions together, but I fail. I also want the child process does not terminate until the parent process terminates. How should I write the parent process? Thanks.

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  • ActionMailer execution timeout

    - by user275729
    When trying to send an email to the user for reseting their password, I keep getting an execution timed out error. Other mailer functions work, so I know that the config settings are correct. The header reads: "Timeout::Error in Password resetsController#create" Here is the password_resets_controller: def create @user = User.find_by_email(params[:email]) if @user User.deliver_password_reset_instructions(@user.id) flash[:notice] = "Instructions to reset your password have been emailed to you. " + "Please check your email." redirect_to '/' else flash[:notice] = "No user was found with that email address" render :action => :new end end Here is the method inside of User.rb def self.deliver_password_reset_instructions(user_id) user = User.find(user_id) user.reset_perishable_token! Emailer.deliver_password_reset_instructions(user) end Finally, here is the actual method inside of emailer.rb: default_url_options[:host] = "http://0.0.0.0:3000" #development def password_reset_instructions(user) @subject = "FanGamb Password Reset" @from = '[email protected]' @recipients = user.email @sent_on = Time.now @body["edit_password_reset_url"] = edit_password_reset_url(user.perishable_token) @headers["X-SMTPAPI"] = "{\"category\" : \"Password Recovery\"}"#send grid category header end Why is "Password" in the error message referred to causing a timeout::error

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  • Can Stopwatch be used in production code?

    - by Adrian
    Hi, I need an accurate timer, and DateTime.Now seems not accurate enough. From the descriptions I read, System.Diagnostics.Stopwatch seems to be exactly what I want. But I have a phobia. I'm nervous about using anything from System.Diagnostics in actual production code. (I use it extensively for debugging with Asserts and PrintLns etc, but never yet for production stuff.) I'm not merely trying to use a timer to benchmark my functions - my app needs an actual timer. I've read on another forum that System.Diagnostics.StopWatch is only for benchmarking, and shouldn't be used in retail code, though there was no reason given. Is this correct, or am I (and whoever posted that advice) being too closed minded about System.Diagnostics? ie, is it ok to use System.Diagnostics.Stopwatch in production code? Thanks Adrian

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  • facebook iframe size not working under https facebook connect

    - by acton
    Follow the following direction in: http://wiki.developers.facebook.com/index.php/Facebook_Connect_Via_SSL to use SSL version facebook connect, some of CanvasUtil functions regarding the resizing doesn't seem to work, the code is as following: FB_RequireFeatures(["Connect","Api","CanvasUtil"], function() { FB.Facebook.init(apiKey, channel,{ "doNotUseCachedConnectState":true }); FB.CanvasClient.getCanvasInfo(function(info){ alert("get it"); }); }); I don't see "get it". If I swtich back to http version, I could get the alert message and things are ok. Does anyone know how to make CanvasUtils from SSL facebook connect working? It might be a bug in facebook. Thanks a lot!

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  • Patterns for simulating optional "out" parameters in C#?

    - by Jesse McGrew
    I'm translating an API from C to C#, and one of the functions allocates a number of related objects, some of which are optional. The C version accepts several pointer parameters which are used to return integer handles to the objects, and the caller can pass NULL for some of the pointers to avoid allocating those objects: void initialize(int *mainObjPtr, int *subObjPtr, int *anotherSubObjPtr); initialize(&mainObj, &subObj, NULL); For the C# version, the obvious translation would use out parameters instead of pointers: public static void Initialize(out int mainObj, out int subObj, out int anotherSubObj); ... but this leaves no way to indicate which objects are unwanted. Are there any well-known examples of C# APIs doing something similar that I could imitate? If not, any suggestions?

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  • Using sphinx to create context sensitive html help

    - by bluebill
    Hi all, I am currently using AsciiDoc (http://www.methods.co.nz/asciidoc/) for documenting my software projects because it supports pdf and html help generation. I am currently running it through cygwin so that the a2x tool chain functions properly. This works well for me but is a pain to setup on other windows computers. I have been looking for alternative methods and recently revisited Sphinx. Noticing that it now produces html help files I gave it a try and it seems to work well in the small tests I performed. My question is, is there a way to specify map id's for context sensitive help in the text so that my windows programs can call the proper help api and the file is launched and opened to the desired location? In AsciiDoc I am using "pass::[]". By using these constructs a context.h and alias.h are generated along with the other html help files (context sensitive help information).

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  • Re-using jQuery widgets

    - by Micor
    I am looking for a most efficient way to re-use widgets with different selectors... For example if I have: $("#selector1").datepicker({ beforeShow: function(var1,var2) { // do stuff }, onClose: function(var1,var2) { // do stuff }, onSelect: function(var1,var2) { // do stuff } }) And later I am looking to assign this same widget with same functions inside to other selectors which are not known at load time. Since its not about choosing a better selector and I want to avoid: $("#new-selector2").datepicker({ beforeShow: function(var1,var2) { // do stuff }, onClose: function(var1,var2) { // do stuff }, onSelect: function(var1,var2) { // do stuff } }) $("#new-selector3").datepicker({ beforeShow: function(var1,var2) { // do stuff }, onClose: function(var1,var2) { // do stuff }, onSelect: function(var1,var2) { // do stuff } }) What would be the best way of doing something like: var reusableDatepicker = datepicker({ beforeShow: function(var1,var2) { // do stuff }, onClose: function(var1,var2) { // do stuff }, onSelect: function(var1,var2) { // do stuff } }) $("#selector1").attach(reusableDatepicker); $("#new-selector2").attach(reusableDatepicker); $("#new-selector3").attach(reusableDatepicker); I know it has to be obvious to all jQuery devs out there, so obvious I cannot find it in docs :) Thank you!

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  • Changing system colors for a single application (Windows, .NET)

    - by Michal Czardybon
    I know I should generally avoid messing up with such system settings, but my application do already use nonstandard colors and I have no influence on that. I would like to be able to add standard .NET controls in some places, but their colors do not match. I would like to have a hack that would replace system colors for this one application. One more important thing to note is that it is a .NET application. My (incomplete) ideas so far were: To create a proxy User32.dll library with replaced GetSysColor, but it would be very tedious (731 functions to be redirected, 1 to be replaced) and I do not know how to force my application to use that particular copy. To intercept somehow invocations to GetSysColors (unfortunatelly it is somewhere in the CLR I think). To modify somehow .NET class SystemColors (in memory? is it possible?). Do you have any idea, what is the best (and complete) way to achieve this?

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  • Guide for http://www.ch-werner.de/javasqlite java wrapper library for SQlite?

    - by Tom Nielsen
    I'm working on a large computer science school project using java and SQlite. After finding out that the zentus.org wrapper errors on databases with ON DELETE and ON UPDATE clauses set, I have changed to the other wrapper found at http://www.ch-werner.de/javasqlite. However, I find the documentation lacking somewhat when trying to get an overview on how it works and how to use it, and the function descriptions are very very short, and you have to scan through every function and somewhat guess how they work and what they do. I wasn't able to find any guides on google on how to use it. My question: Does anyone know a link for a guide or tutorial for the ch-werner.de/javasqlite wrapper, or else can give me a basic code example, or give a quick overview of querying the database and the most used functions, and how to use them?

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  • Huge file in Clojure and Java heap space error

    - by trzewiczek
    I posted before on a huge XML file - it's a 287GB XML with Wikipedia dump I want ot put into CSV file (revisions authors and timestamps). I managed to do that till some point. Before I got the StackOverflow Error, but now after solving the first problem I get: java.lang.OutOfMemoryError: Java heap space error. My code (partly taken from Justin Kramer answer) looks like that: (defn process-pages [page] (let [title (article-title page) revisions (filter #(= :revision (:tag %)) (:content page))] (for [revision revisions] (let [user (revision-user revision) time (revision-timestamp revision)] (spit "files/data.csv" (str "\"" time "\";\"" user "\";\"" title "\"\n" ) :append true))))) (defn open-file [file-name] (let [rdr (BufferedReader. (FileReader. file-name))] (->> (:content (data.xml/parse rdr :coalescing false)) (filter #(= :page (:tag %))) (map process-pages)))) I don't show article-title, revision-user and revision-title functions, because they just simply take data from a specific place in the page or revision hash. Anyone could help me with this - I'm really new in Clojure and don't get the problem.

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  • Returning structs in registers - ARM ABI in GCC

    - by jbcreix
    Hi, In the ARM ABI documentation I come across functions defined like: __value_in_regs struct bar foo(int a, int b) { ... } but GCC(4.3.3) doesn't allow it and all I could find are references to some RealView compiler. Is there any way of doing this from GCC? I have tried -freg-struct-return but it doesn't make a difference. As it is an ABI I can't change the original programs, and returning a regular struct mangles the stack. I would rather not using assembly for this if avoidable as it isn't otherwise necessary. Thanks!

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  • Function pointer arrays in Fortran

    - by Eduardo Dobay
    I can create function pointers in Fortran 90, with code like real, external :: f and then use f as an argument to another function/subroutine. But what if I want an array of function pointers? In C I would just do double (*f[])(int); to create an array of functions returning double and taking an integer argument. I tried the most obvious, real, external, dimension(3) :: f but gfortran doesn't let me mix EXTERNAL and DIMENSION. Is there any way to do what I want? (The context for this is a program for solving a system of differential equations, so I could input the equations without having a million parameters in my subroutines.)

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  • Math: How to sum each row of a matrix

    - by macek
    I have a 1x8 matrix of students where each student is a 4x1 matrix of scores. Something like: SCORES S [62, 91, 74, 14] T [59, 7 , 59, 21] U [44, 9 , 69, 6 ] D [4 , 32, 28, 53] E [78, 99, 53, 83] N [48, 86, 89, 60] T [56, 71, 15, 80] S [47, 67, 79, 40] Main question: Using sigma notation, or some other mathematical function, how can I get a 1x8 matrix where each student's scores are summed? # expected result TOTAL OF SCORES S [241] T [146] U [128] D [117] E [313] N [283] T [222] S [233] Sub question. To get the average, I will multiply the matrix by 1/4. Would there be a quicker way to get the final result? AVERAGE SCORE S [60.25] T [36.50] U [32.00] D [29.25] E [78.25] N [70.75] T [55.50] S [58.25] Note: I'm not looking for programming-related algorithms here. I want to know if it is possible to represent this with pure mathematical functions alone.

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  • Getting help on MATLAB's com.mathworks internals

    - by Richie Cotton
    It is possible to access bits of MATLAB's internal java code to programmatically change MATLAB itself. For example, you can programmatically open a document in the editor using editorServices = com.mathworks.mlservices.MLEditorServices; editorServices.newDocument() %older versions of MATLAB seem to use new() You can see the method signatures (but not what they do) using viewmethods. viewmethods(com.mathworks.mlservices.MLEditorServices) I have a few related questions about using these Java methods. Firstly, is there any documentation on these things (either from the Mathworks or otherwise)? Secondly, how do you find out what methods are available? The ones I've come across appear to be contained in JAR files in matlabroot\java\jar, but I'm not sure what the best way to inspect a JAR file is. Thirdly, are there functions for inspecting the classes, other than viewmethods? Finally, are there any really useful methods that anyone has found?

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  • add schema to path in postgresql

    - by veilig
    I'm the process of moving applications over from all in the public schema to each having their own schema. for each application, I have a small script that will create the schema and then create the tables,functions,etc... to that schema. Is there anyway to automatically add a newly created schema to the search_path? Currently, the only way I see is to find the users current path SHOW search_path; and then add the new schema to it SET search_path to xxx,yyy,zzz; I would like some way to just say, append schema zzz to the users_search path. is this possible?

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  • Calling C function from DTrace scripts

    - by dmeister
    DTrace is impressive, powerful tracing system originally from Solaris, but it is ported to FreeBSD and Mac OSX. DTrace uses a high-level language called D not unlike AWK or C. Here is an example: io:::start /pid == $1/ { printf("file %s offset %d size %d block %llu\n", args[2]->fi_pathname, args[2]->fi_offset, args[0]->b_bcount, args[0]->b_blkno); } Using the command line sudo dtrace -q -s <name>.d <pid> all IOs originated from that process are logged. My question is if and how it is possible to call custom C functions from a DTrace script to do advanced operations with that tracing data during the tracing itself.

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  • Finding distance travelled by robot using Optical Flow

    - by user280454
    Hi, I'm working on a project right now in which we are developing an autonomous robot. I have to basically find out the distance travelled by the robot between any 2 intervals. I'm using OpenCV, and using the Optical Flow functions of OpenCV, I'm able to find out the velocity/distance of each pixel in 2 different images. Using this information, I want to be able to find out the distance travelled by the robot in the interval between those 2 images. I thought of a way in which we could develop an input output mapping between the distance travelled by pixels and the distance travelled by the bot (using some tests). In this way, using neural networks, we would be able to find the relationship. However, the optical flow would depend on the distance of the camera from the pixel, which would cause problems. Is there any way to solve this problem?

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  • Probability distribution for sms answer delays

    - by Thomas Ahle
    I'm writing an app using sms as communication. I have chosen to subscribe to an sms-gateway, which provides me with an API for doing so. The API has functions for sending as well as pulling new messages. It does however not have any kind of push functionality. In order to do my queries most efficient, I'm seeking data on how long time people wait before they answer a text message - as a probability function. Extra info: The application is interactive (as can be), so I suppose the times will be pretty similar to real life human-human communication. I don't believe differences in personal style will play a big impact on the right times and frequencies to query, so average data should be fine.

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