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• How to paint fully transparent pixels/points in P2D mode?

  - by netzwerg

  According to the Processing Reference, stroke(gray, alpha) allows to set the color and opacity of the stroke. With the default color mode, an alpha value of 255 denotes full opacity, while a value of 0 should correspond to complete transparency. While this works with the (default) JAVA2D renderer, I can't seem to paint fully transparent points in P2D mode. This code clearly renders a pixel at the center of the canvas, even though the alpha value is set to 0 (fully transparent): public class Transparency extends PApplet { @Override public void setup() { size(200, 200, P2D); } @Override public void draw() { stroke(0, 0); point(width / 2, height / 2); } public static void main(String[] args) { PApplet.main(new String[] { Transparency.class.getSimpleName() }); } } What's wrong here?

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• Image 8-connectivity without excessive branching?

  - by shoosh

  I'm writing a low level image processing algorithm which needs to do alot of 8-connectivity checks for pixels. For every pixel I often need to check the pixels above it, below it and on its sides and diagonals. On the edges of the image there are special cases where there are only 5 or 3 neighbors instead of 8 neighbors for a pixels. The naive way to do it is for every access to check if the coordinates are in the right range and if not, return some default value. I'm looking for a way to avoid all these checks since they introduce a large overhead to the algorithm. Are there any tricks to avoid it altogether?

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• How to use DoG Pyramid in SIFT

  - by Ahmet Keskin

  Hi all, I am very new in image processing and pattern recognition. I am trying to implement SIFT algorithm where I am able to create the DoG pyramid and identify the local maximum or minimum in each octave. What I don't understand is that how to use these local max/min in each octave. How do I combine these points? My question may sound very trivial. I have read Lowe's paper, but could not really understand what he did after he built the DoG pyramid. Any help is appreciated. Thank you

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• Need PHP Email Script Solution

  - by JCHASE11

  Designing forms has always been fun, but getting them to send email on the server side is another story. I have used various email scripts (dynaform,phpmailer, etc), and have experienced a ton of problems. So here is the site I am working on: Contact On the Right. It is very basic: no validation, no required fields. I simply need anything that is entered to be sent back to me. Does anyone know of any BASIC PHP form processing scripts, or have a few lines of code that would work here? I'm not a PHP guy, so I am struggling! Thanks in advance.

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• How do I create an OpenCV image from a PIL image?

  - by scrible

  I want to do some image processing with OpenCV (in Python), but I have to start with a PIL Image object, so I can't use the cvLoadImage() call, since that takes a filename. This recipe (adapted from http://opencv.willowgarage.com/wiki/PythonInterface) does not work because cvSetData complains argument 2 of type 'void *' . Any ideas? from opencv.cv import * from PIL import Image pi = Image.open('foo.png') # PIL image ci = cvCreateImage(pi.size, IPL_DEPTH_8U, 1) # OpenCV image data = pi.tostring() cvSetData(ci, data, len(data)) I think the last argument to the cvSetData is wrong too, but I am not sure what it should be.

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• Browser Side Photo Editing Library

  - by echox

  Hi! Currently I'm searching for a free solution to simple edit some photos at the users browser. Resizing and Cropping would be mandatory. I'm not searching for an online service (for example SUMO or PIXLR which are great), because I want to include the software into a WYSIWYG Editor. JavaScript would be really nice, but it would have to work in IE 8. Pixastic is a great example, but works only in modern browsers (not IE 8 :-/) Any suggestions what I could use? Maybe setting up some kind of image processing service with ImageMagick and communicating with it through AJAX could also be an solution? Has anyone gained some experience with such a solution?

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• Making Overlaid image transparent on touch in Android ?

  - by Andhravaala

  Hi All, I need help on making the touched areas of bitmap image transparent(seems like erasing) while I am moving my finger on that image. I am having a PNG file with Alpha channel in it. I want to turn the touched pixels to transparent so that, the user can feel that he is actually erasing it. For this I am using frame layout to load 2 layers. Down layer is for content and upper layer is an Imageview for erasing. I need erase the upper layer when user touch and move his finger on it. I am not getting how to make it transparent. can anyone please help me in this. If possible please direct me to any sample code, as I am very new to this image processing. Thanks in advance.

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• Erlang message loops

  - by Roger Alsing

  How does message loops in erlang work, are they sync when it comes to processing messages? As far as I understand, the loop will start by "receive"ing a message and then perform something and hit another iteration of the loop. So that has to be sync? right? If multiple clients send messages to the same message loop, then all those messages are queued and performed one after another, or? To process multiple messages in parallell, you would have to spawn multiple message loops in different processes, right? Or did I misunderstand all of it?

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• Plotting Points in Java with Interaction

  - by mellort

  I have a large number of data points which are two dimensional coordinates with non-integer values (floats). I am looking for a Java library that can help me plot these points, allowing for custom point size, color, and labels. Further, I would like the user to be able to interact with the points with panning and zooming, and I want to be able to capture KeyEvents from the user. Processing looks great for what I want, but I don't want to do everything from scratch. Is there a better solution? Thanks in advance.

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• OpenMP: Get total number of running threads

  - by Konrad Rudolph

  I need to know the total number of threads that my application has spawned via OpenMP. Unfortunately, the omp_get_num_threads() function does not work here since it only yields the number of threads in the current team. However, my code runs recursively (divide and conquer, basically) and I want to spawn new threads as long as there are still idle processors, but no more. Is there a way to get around the limitations of omp_get_num_threads and get the total number of running threads? If more detail is required, consider the following pseudo-code that models my workflow quite closely: function divide_and_conquer(Job job, int total_num_threads): if job.is_leaf(): # Recurrence base case. job.process() return left, right = job.divide() current_num_threads = omp_get_num_threads() if current_num_threads < total_num_threads: # (1) #pragma omp parallel num_threads(2) #pragma omp section divide_and_conquer(left, total_num_threads) #pragma omp section divide_and_conquer(right, total_num_threads) else: divide_and_conquer(left, total_num_threads) divide_and_conquer(right, total_num_threads) job = merge(left, right) If I call this code with a total_num_threads value of 4, the conditional annotated with (1) will always evaluate to true (because each thread team will contain at most two threads) and thus the code will always spawn two new threads, no matter how many threads are already running at a higher level. I am searching for a platform-independent way of determining the total number of threads that are currently running in my application.

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• Physical Cores vs Virtual Cores in Parallelism

  - by Code Curiosity

  When it comes to virtualization, I have been deliberating on the relationship between the physical cores and the virtual cores, especially in how it effects applications employing parallelism. For example, in a VM scenario, if there are less physical cores than there are virtual cores, if that's possible, what's the effect or limits placed on the application's parallel processing? I'm asking, because in my environment, it's not disclosed as to what the physical architecture is. Is there still much advantage to parallelizing if the application lives on a dual core VM hosted on a single core physical machine?

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• Image analysis on the iPhone

  - by user362808

  Hi, guys! Hopefully a quick one. Working on a devious little algorithm that'll automatically scan a user's iPhone for a photo of some emotional poignance (e.g. go back in time a ways, look for one of a group of photos that are proximally timestamped, etc.). Need a quick-and-dirty way of picking out a photo containing two people in close proximity to each other. I know that the OpenCV Python lib [for image processing] works on the iPhone, I'm just curious whether it's actually the best way of doing this (from scratch or otherwise). Cheers!

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• Background subtracting in MATLAB

  - by eiphyomin

  I'm looking to do background subtracting on an image. I'm new to MATLAB and new to image processing/analysis, so sorry if any of this sounds stupid. 1) Other than imsubtract() are there other ways to do background subtracting (besides comparing one image to another)? 2) In the Math Works explanation for imsubtract() why do they make their structuring element a disk? This seems rather difficult so far because every time I try something, I end up not only subtracting the noisy background but also losing the parts of the image I want to look at!

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• Forcing a mixed ISO-8859-1 and UTF-8 multi-line string into UTF-8 in Perl

  - by knorv

  Consider the following problem: A multi-line string $junk contains some lines which are encoded in UTF-8 and some in ISO-8859-1. I don't know a priori which lines are in which encoding, so heuristics will be needed. I want to turn $junk into pure UTF-8 with proper re-encoding of the ISO-8859-1 lines. Also, in the event of errors in the processing I want to provide a "best effort result" rather than throwing an error. My current attempt looks like this: $junk = &force_utf8($junk); sub force_utf8 { my $input = shift; my $output = ''; foreach my $line (split(/\n/, $input)) { if (utf8::valid($line)) { utf8::decode($line); } $output .= "$line\n"; } return $output; } While this appears to work I'm certain this is not the optimal solution. How would you improve the force_utf8(...) sub?

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• List of uninteresting words

  - by Hooked

  [Caveat] This is not directly a programing question, but it is something that comes up so often in language processing that I'm sure it's of some use to the community. Does anyone have a good list of uninteresting (English) words that have been tested by more then a casual look? This would include all prepositions, conjunctions, etc... words that may have semantic meaning, but are often frequent in every sentence, regardless of the subject. I've built my own lists from time to time for personal projects but they've been ad-hoc; I continuously add words that I forgotten as they come in.

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• Take advantage of multiple cores executing SQL statements

  - by willvv

  I have a small application that reads XML files and inserts the information on a SQL DB. There are ~ 300 000 files to import, each one with ~ 1000 records. I started the application on 20% of the files and it has been running for 18 hours now, I hope I can improve this time for the rest of the files. I'm not using a multi-thread approach, but since the computer I'm running the process on has 4 cores I was thinking on doing it to get some improvement on the performance (although I guess the main problem is the I/O and not only the processing). I was thinking on using the BeginExecutingNonQuery() method on the SqlCommand object I create for each insertion, but I don't know if I should limit the max amount of simultaneous threads (nor I know how to do it). What's your advice to get the best CPU utilization? Thanks

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• How would you find the height of objects given an image?

  - by Ram Bhat

  Heyguys.. This isn't exactly a programming question exactly. I just want to know what your approach would be to a common problem in Digital image processing. Lets say you have an image of a a few trees in say jpg format. How would you go about finding the heights of each of these trees. The photo is the only input you have. I want to know the approaches you have not code. So it doesnt matter if your answers are vague, or non DIP-ish.

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• What's going on with my server? High load, lots of idle CPU time, low disk utilization

  - by Jonathan

  I run a web site and send a legitimate opt-in, daily email newsletter to subscribers. Both the web hosting and email sending are done by the same machine. I have about 100,000 subscribers who have opted in to my daily email newsletter. My PHP script did a pretty good job sending mail to all of them until fairly recently, but as the list has grown I can't keep up. When I run top, I have very high load--usually at least 6 or 7, sometimes as high as 15--even though I only have two CPUs. However, when I run sar, my CPU is idle an average of about 30% of the time. So, it seems I'm not CPU bound. When I run iostat, it seems as though I'm not disk bound because my %util for each device is very low (no more than 5%). Given that I don't seem to be CPU bound or disk bound, why is top reporting such high load? Additionally, since I don't seem to be CPU bound or disk bound, why is my email sending script not able to keep up? Here's what I see when running top: top - 11:33:28 up 74 days, 18:49, 2 users, load average: 7.65, 8.79, 8.28 Tasks: 168 total, 5 running, 162 sleeping, 0 stopped, 1 zombie Cpu(s): 38.9%us, 58.6%sy, 0.8%ni, 0.0%id, 0.7%wa, 0.2%hi, 0.8%si, 0.0%st Mem: 3083012k total, 2144436k used, 938576k free, 281136k buffers Swap: 2048248k total, 39164k used, 2009084k free, 1470412k cached Here's what I see when running iostat -mx: avg-cpu: %user %nice %system %iowait %steal %idle 34.80 1.20 55.24 0.37 0.00 8.38 Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util sda 0.19 71.70 1.59 29.45 0.02 0.07 5.90 0.55 17.82 1.16 3.59 sda1 0.00 0.00 0.00 0.00 0.00 0.00 7.10 0.00 13.80 13.72 0.00 sda2 0.05 50.45 1.13 24.57 0.01 0.29 24.25 0.35 13.43 1.15 2.97 sda3 0.05 10.17 0.20 2.33 0.01 0.05 43.75 0.05 20.96 2.45 0.62 sda4 0.00 0.00 0.00 0.00 0.00 0.00 2.00 0.00 70.50 70.50 0.00 sda5 0.07 0.22 0.03 0.07 0.00 0.00 32.84 0.08 856.19 8.03 0.08 sda6 0.02 5.45 0.03 0.72 0.00 0.02 67.55 0.02 26.72 5.26 0.39 sda7 0.00 1.56 0.00 0.42 0.00 0.01 38.04 0.00 8.88 5.84 0.24 sda8 0.01 3.84 0.20 1.35 0.00 0.02 28.55 0.05 31.90 4.08 0.63 Here's what I see when running sar: 09:40:02 AM CPU %user %nice %system %iowait %steal %idle 09:50:01 AM all 30.59 1.01 49.80 0.23 0.00 18.37 10:00:08 AM all 31.73 0.92 51.66 0.13 0.00 15.55 10:10:06 AM all 30.43 0.99 48.94 0.26 0.00 19.38 10:20:01 AM all 29.58 1.00 47.76 0.25 0.00 21.42 10:30:01 AM all 29.37 1.02 47.30 0.18 0.00 22.13 10:40:06 AM all 32.50 1.01 52.94 0.16 0.00 13.39 10:50:01 AM all 30.49 1.00 49.59 0.15 0.00 18.77 11:00:01 AM all 29.43 0.99 47.71 0.17 0.00 21.71 11:10:07 AM all 30.26 0.93 49.48 0.83 0.00 18.50 11:20:02 AM all 29.83 0.81 48.51 1.32 0.00 19.52 11:30:06 AM all 31.18 0.88 51.33 1.15 0.00 15.47 Average: all 26.21 1.15 42.62 0.48 0.00 29.54 Here are the top handful of processes listed at the particular time I happened to run top -c: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 8180 mysql 16 0 57448 19m 2948 S 26.6 0.7 4702:26 /usr/sbin/mysqld --basedir=/ --datadir=/var/lib/mysql --user=mysql --pid-file=/var/lib/mysql/bristno.pid --skip-external-locking 26956 brristno 17 0 0 0 0 Z 8.0 0.0 0:00.24 [php] <defunct> 26958 brristno 17 0 94408 43m 37m R 5.0 1.4 0:00.15 /usr/bin/php /home/brristno/public_html/dbv.php 22852 nobody 16 0 9628 2900 1524 S 0.7 0.1 0:00.17 /usr/local/apache/bin/httpd -k start -DSSL 8591 brristno 34 19 96896 13m 6652 S 0.3 0.4 0:29.82 /usr/local/bin/php /home/brristno/bin/mailer.php 1qwqyb6 i0gbor 24469 nobody 16 0 9628 2880 1508 S 0.3 0.1 0:00.08 /usr/local/apache/bin/httpd -k start -DSSL 25495 nobody 15 0 9628 2876 1500 S 0.3 0.1 0:00.06 /usr/local/apache/bin/httpd -k start -DSSL 26149 nobody 15 0 9628 2864 1504 S 0.3 0.1 0:00.04 /usr/local/apache/bin/httpd -k start -DSSL

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• Vmware software installation error

  - by Perry

  I am trying to install Vmware software, but I am facing the following error: Selecting previously unselected package vmware-view-client:i386. (Reading database ... 239594 files and directories currently installed.) Unpacking vmware-view-client:i386 (from .../vmware-view-client_2.1.0-0ubuntu0.12.04_i386.deb) ... Processing triggers for desktop-file-utils ... Processing triggers for bamfdaemon ... Rebuilding /usr/share/applications/bamf.index... Processing triggers for gnome-menus ... Setting up icaclient:i386 (12.1.0) ... dpkg: error processing icaclient:i386 (--configure): subprocess installed post-installation script returned error exit status 2 Setting up vmware-view-client:i386 (2.1.0-0ubuntu0.12.04) ... Processing triggers for libc-bin ... ldconfig deferred processing now taking place Errors were encountered while processing: icaclient:i386 E: Sub-process /usr/bin/dpkg returned an error code (1) A package failed to install. Trying to recover: Setting up icaclient:i386 (12.1.0) ... dpkg: error processing icaclient:i386 (--configure): subprocess installed post-installation script returned error exit status 2 Errors were encountered while processing: icaclient:i386 Any suggestions on how to fix this issue? Thanks in advance

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• Error when I try to installth desktop integration features for Openoffice

  - by PENG TENG

  peng@peng-ThinkPad-SL410:~$ cd '/home/peng/Downloads/en-US/DEBS/desktop-integration' peng@peng-ThinkPad-SL410:~/Downloads/en-US/DEBS/desktop-integration$ sudo dpkg -i *.deb (Reading database ... 357248 files and directories currently installed.) Unpacking openoffice.org-debian-menus (from openoffice.org3.4-debian-menus_3.4-9593_all.deb) ... dpkg: error processing openoffice.org3.4-debian-menus_3.4-9593_all.deb (--install): trying to overwrite '/usr/bin/soffice', which is also in package libreoffice-common 1:3.6.2~rc2-0ubuntu3 /usr/bin/gtk-update-icon-cache gtk-update-icon-cache: Cache file created successfully. /usr/bin/gtk-update-icon-cache gtk-update-icon-cache: Cache file created successfully. Processing triggers for menu ... Processing triggers for hicolor-icon-theme ... Processing triggers for gnome-icon-theme ... Processing triggers for shared-mime-info ... Unknown media type in type 'all/all' Unknown media type in type 'all/allfiles' Unknown media type in type 'uri/mms' Unknown media type in type 'uri/mmst' Unknown media type in type 'uri/mmsu' Unknown media type in type 'uri/pnm' Unknown media type in type 'uri/rtspt' Unknown media type in type 'uri/rtspu' Processing triggers for bamfdaemon ... Rebuilding /usr/share/applications/bamf.index... Processing triggers for desktop-file-utils ... Processing triggers for gnome-menus ... Errors were encountered while processing: openoffice.org3.4-debian-menus_3.4-9593_all.deb Can anyone solve the problem?

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• Eigenvector computation using OpenCV

  - by Andriyev

  Hi I have this matrix A, representing similarities of pixel intensities of an image. For example: Consider a 10 x 10 image. Matrix A in this case would be of dimension 100 x 100, and element A(i,j) would have a value in the range 0 to 1, representing the similarity of pixel i to j in terms of intensity. I am using OpenCV for image processing and the development environment is C on Linux. Objective is to compute the Eigenvectors of matrix A and I have used the following approach: static CvMat mat, *eigenVec, *eigenVal; static double A[100][100]={}, Ain1D[10000]={}; int cnt=0; //Converting matrix A into a one dimensional array //Reason: That is how cvMat requires it for(i = 0;i < affnDim;i++){ for(j = 0;j < affnDim;j++){ Ain1D[cnt++] = A[i][j]; } } mat = cvMat(100, 100, CV_32FC1, Ain1D); cvEigenVV(&mat, eigenVec, eigenVal, 1e-300); for(i=0;i < 100;i++){ val1 = cvmGet(eigenVal,i,0); //Fetching Eigen Value for(j=0;j < 100;j++){ matX[i][j] = cvmGet(eigenVec,i,j); //Fetching each component of Eigenvector i } } Problem: After execution I get nearly all components of all the Eigenvectors to be zero. I tried different images and also tried populating A with random values between 0 and 1, but the same result. Few of the top eigenvalues returned look like the following: 9805401476911479666115491135488.000000 -9805401476911479666115491135488.000000 -89222871725331592641813413888.000000 89222862280598626902522986496.000000 5255391142666987110400.000000 I am now thinking on the lines of using cvSVD() which performs singular value decomposition of real floating-point matrix and might yield me the eigenvectors. But before that I thought of asking it here. Is there anything absurd in my current approach? Am I using the right API i.e. cvEigenVV() for the right input matrix (my matrix A is a floating point matrix)? cheers

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• Gmagick extension for php install -- how and where?

  - by Vivek Chandra

  Downloaded php-pear and tried installing gmagick extension by following the steps given in link "http://www.gerd-riesselmann.net/development/how-install-imagick-and-gmagick-ubuntu" The pecl gave an error -- gmagick-1.0.9b1$ pecl install gmagick Failed to download pecl/gmagick within preferred state "stable", latest release is version 1.0.9b1, stability "beta", use "channel://pecl.php.net/gmagick-1.0.9b1" to install install failed Tried adding the channel (no result)-- gmagick-1.0.9b1$ pecl channel-add http://pecl.php.net/package/gmagick/1.0.9b1 Error: No version number found in tag channel-add: invalid channel.xml file Found the link "http://pecl.php.net/package/gmagick" to download the php extension untar'd it to find the following files -- gmagick-1.0.9b1$ ls config.m4 gmagickdraw_methods.c gmagick_methods.c LICENSE php_gmagick_helpers.h README gmagick.c gmagick_helpers.c gmagickpixel_methods.c php_gmagick.h php_gmagick_macros.h Tried . / config.m4 only to find more errors gmagick-1.0.9b1$ . / config.m4 ./config.m4: line 1: syntax error near unexpected token `gmagick,' ./config.m4: line 1: `PHP_ARG_WITH(gmagick, whether to enable the gmagick extension,' Been at this since a day with no result.Read that gmagick is a swiss knife of image processing,sad that there isnt much documentation done on it or at least a proper how to install link anywhere. Badly need help. Thanks in advance.

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• Using regex to extract variables from a plain-text form letter?

  - by Yaaqov

  Hi - I'm looking for a good example of using Regular Expressions in PHP to "reverse engineer" a form letter (with a known format, of course) that has been pasted into a multiline textbox and sent to a script for processing. So, for example, let's assume this is the original plain-text input (taken from a USDA press release): WASHINGTON, April 5, 2010 - North American Bison Co-Op, a New Rockford, N.D., establishment is recalling approximately 25,000 pounds of whole beef heads containing tongues that may not have had the tonsils completely removed, which is not compliant with regulations that require the removal of tonsils from cattle of all ages, the U.S. Department of Agriculture's Food Safety and Inspection Service (FSIS) announced today. For clarity, the fields that are variables are highlighted below: [pr_city=]WASHINGTON, [pr_date=]April 5, 2010 - [corp_name=]North American Bison Co-Op, a [corp_city=]New Rockford, [corp_state=]N.D., establishment is recalling approximately [amount=]25,000 pounds of [product=]whole beef heads containing tongues that may not have had the tonsils completely removed, which is not compliant with regulations that require [reason=]the removal of tonsils from cattle of all ages, the U.S. Department of Agriculture's Food Safety and Inspection Service (FSIS) announced today. How could I efficiently extract the contents of the pr_city pr_date corp_name corp_city corp_state amount product reason fields from my example? Any help would be appreciated, thanks.

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• How to do recurring with bank account payment mode using authorized.net

  - by Salil

  Hi All, I am using recurring facility of authorized.net using active_merchant plugin in rails. there are two payment method for this 1] Credit Card 2] Bank Account I successfully done it using Credit Card For Recurring i need my Test Mode off. Also my E-check, credit card processing, and subscriptions are all enabled. But i am not able to subscribed using Bank Account Following is my code ActiveMerchant::Billing::Base.mode = :developer #i found follwing test bank account on net account = ActiveMerchant::Billing::Check.new(:account_holder_type=>"personal",:account_number=>"123123123", :account_type => "savings", :name=>"name", :routing_number=>"244183602") if account.valid? #this comes true gateway = ActiveMerchant::Billing::AuthorizeNetGateway.new(:login => 'Mylogin', :password => 'Mypassword') response = gateway.recurring( amount, nil, {:interval =>{:length=>@length, :unit =>:months}, :duration =>{:start_date=>'2010-04-24', :occurrences=>1}, :billing_address=>{:first_name=>'dinesh', :last_name=>'singh'}, :bank_account=>{:account_holder_type=>"personal",:account_number=>"123123123", :account_type => "savings", :name_of_account=>"name", :routing_number=>"244183602"} }) if response.success? #this comes false else puts response.message ####>> ERROR render :action=>"account_payment" end I get Follwing ERROR when i debug for response.message "The test transaction was not successful. (128) This transaction cannot be processed." Am i doing anything wrong i search for the another Test Bank Account Data but i didn't find it. Please help I badly need it. Thanks in Advance. Regards, Salil Gaikwad

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• What is the most efficient way to display decoded video frames in Qt?

  - by Jason

  What is the fastest way to display images to a Qt widget? I have decoded the video using libavformat and libavcodec, so I already have raw RGB or YCbCr 4:2:0 frames. I am currently using a QGraphicsView with a QGraphicsScene object containing a QGraphicsPixmapItem. I am currently getting the frame data into a QPixmap by using the QImage constructor from a memory buffer and converting it to QPixmap using QPixmap::fromImage(). I like the results of this and it seems relatively fast, but I can't help but think that there must be a more efficient way. I've also heard that the QImage to QPixmap conversion is expensive. I have implemented a solution that uses an SDL overlay on a widget, but I'd like to stay with just Qt since I am able to easily capture clicks and other user interaction with the video display using the QGraphicsView. I am doing any required video scaling or colorspace conversions with libswscale so I would just like to know if anyone has a more efficient way to display the image data after all processing has been performed. Thanks.

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