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  • Writing temporary data from R

    - by Shane
    I want to write some temporary data to disk in an R package, and I want to be sure that it can run on every OS without assuming the user has admin rights. Is there an existing R function that can provide a path to a temporary directory on all major OS's? Or a way to reference a user's home directory? Otherwise, I was thinking of trying this: Sys.getenv("temp") I presume that I can't expect people to have write access to their R locations, otherwise I could reference a path within the package directory: .find.package("package.name").

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  • touches event handler for UIImageView

    - by madmik3
    I am just getting stated with iPhone development and can't seem to find the answer I am looking for what I want to do. It seems like I should be able to programmatically create a UIImageView and then set up an event handler for it's touch functions. in c# i would have something that looks like Button b = new Button(); b.Click+= my handler code right now I have this CGRect myImageRect = CGRectMake(0.0f, 0.0f, 141.0f, 151.0f); UIImageView *myImage = [[UIImageView alloc] initWithFrame:myImageRect]; myImage.userInteractionEnabled = YES; [myImage setImage:[UIImage imageNamed:@"myImage.png"]]; myImage.opaque = YES; // explicitly opaque for performance [self.view addSubview:myImage]; [myImage release]; What do I need to do to override the touch events? thanks

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  • Add Core Data Index to certain Attributes via migration

    - by steipete
    For performance reasons, i want to set the Indexed Attribute to some of my entities. I created a new core data model version to perform the changes. Core Data detects the changes and migrates my model to the new version, however, NO INDEXES ARE GENERATED. If I recreate the database from scratch, the indexes are there. I checked with SQLite Browser both on the iPhone and on the Simulator. The problem only occurs if a database in the prior format is already there. Is there a way to manually add the indexes? Write some sql for that? Or am I missing something? I did already some more critical migrations, no problems there. But those missing indexes are bugging me. Thanks for helping!

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  • How can I calculate data for a boxplot (quartiles, median) in a Ralis app on Heroku? ( Heroku uses P

    - by hadees
    I'm trying to calculate the data needed to generate a box plot which means I need to figure out the 1st and 3rd Quartiles along with the median. I have found some solutions for doing it in Postgresql however they seem to depend on either PL/Python or PL/R which it seems like Heroku does not have either enabled for their postgresql databases. In fact I ran "select lanname from pg_language;" and only got back "internal". I also found some code to do it in pure ruby but that seems somewhat inefficient to me. I'm rather new to Box Plots, Postgresql, and Ruby on Rails so I'm open to suggestions on how I should handle this. There is a possibility to have a lot of data which is why I'm concerned with performance however if the solution ends up being too complex I may just do it in ruby and if my application gets big enough to warrant it get my own Postgresql I can host somewhere else. *note: since I was only able to post one link, cause I'm new, I decided to share a pastie with some relevant information

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  • SDK for writing DVD's

    - by Matt Warren
    I need to add DVD writing functionality to an application I'm working on. However it needs to be able to write out files that are being grabbed "live" from a camera, over a long period of time. I can't wait until all the files are captured before I start writing them to the DVD, I need to write them out in chunks as I go along. I've looked at IMAPI v2, but the main problems seems to be that you need to point it to all the files you plan to write out to disk before you start the burning process. I know it has to concept of "sessions", which means you can write to the DVD in several parts, before you finally "close" it. But I was wondering if there were any other DVD writing SDK's that allow you to be constantly writing files to a DVD and in particular files that are only in memory. It would be more efficient if I didn't have to write the captured images out to hard before they are burned to DVD. The solution needs to work under .NET on Windows XP and vista

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  • Portable C++ library for IPC (processes and shared memory), Boost vs ACE vs Poco?

    - by user363778
    Hi, I need a portable C++ library for doing IPC. I used fork() and SysV shared memory until now but this limits me to Linux/Unix. I found out that there are 3 major C++ libraries that offer a portable solution (including Windows and Mac OS X). I really like Boost, and would like to use it but I need processes and it seems like that this is only an experimental branch until now!? I have never heard of ACE or POCO before and thus I am stuck I do not know which one to choose. I need fork(), sleep() (usleep() would be great) and shared memory of course. Performance and documentation are also important criteria. Thanks, for your Help!

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  • Best Way to transfer data From one page to another In asp.net.

    - by Anish Karunakaran
    In my scenario am using java script popup that popups another form Which is an address Entry form of merely 20 Controls in it. Now am retrieving data from address page to main page by using a session variable which stores a data table of values. Two different Session variables are this way used for permanent and temporary addresses.. Using session variable degrades the performance i know.. What is the best way to transfer value from one page to another. Regards anish.

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  • Tokenizer for full-text

    - by user72185
    This should be an ideal case of not re-inventing the wheel, but so far my search has been in vain. Instead of writing one myself, I would like to use an existing C++ tokenizer. The tokens are to be used in an index for full text searching. Performance is very important, I will parse many gigabytes of text. Edit: Please note that the tokens are to be used in a search index. Creating such tokens is not an exact science (afaik) and requires some heuristics. This has been done a thousand time before, and probably in a thousand different ways, but I can't even find one of them :) Any good pointers? Thanks!

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  • fd.seek() IOError: [Errno 22] Invalid argument

    - by Julian Kessel
    My Python Interpreter (v2.6.5) raises the above error in the following codepart: fd = open("some_filename", "r") fd.seek(-2, os.SEEK_END) #same happens if you exchange the second arg. w/ 2 data=fd.read(2); last call is fd.seek() Traceback (most recent call last): File "bot.py", line 250, in <module> fd.seek(iterator, os.SEEK_END); IOError: [Errno 22] Invalid argument The strange thing with this is that the exception occurs just when executing my entire code, not if only the specific part with the file opening. At the runtime of this part of code, the opened file definitely exists, disk is not full, the variable "iterator" contains a correct value like in the first codeblock. What could be my mistake? Thanks in advance

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  • windows I/O manager - IRP's classification in read-like and write-like

    - by clyfe
    I am writing a windows filesystem minifilter driver that must fail IRP's in a preoperation callback. How can I find out from the callback parameters if the operation is read-like ( only reads data ) or it's write-like ( modifies data on the disk - write, delete etc ) ? I'm thinking on: Data->Iopb->TargetFileObject->ReadAccess Data->Iopb->TargetFileObject->WriteAccess But I'm not sure, I think thees are available only in postoperation callback. The documentation is really cumbersome. Code sample: FLT_PREOP_CALLBACK_STATUS Fail ( __inout PFLT_CALLBACK_DATA Data, __in PCFLT_RELATED_OBJECTS FltObjects, __deref_out_opt PVOID *CompletionContext ) { FLT_PREOP_CALLBACK_STATUS status = FLT_PREOP_SUCCESS_NO_CALLBACK; if ( IS WRITE_LIKE(Data, FltObjects) ) { // ??? HOW DO I FIND OUT???? if( FLT_IS_FASTIO_OPERATION(Data) ){ status = FLT_PREOP_DISALLOW_FASTIO; } else { status = FLT_PREOP_COMPLETE; } Data->IoStatus.Status = STATUS_ACCESS_DENIED; Data->IoStatus.Information = 0; return status; } return status; }

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  • which is the best for build a Gantt-chart like application Flex or Flash Action Script?

    - by coderex
    Which is the best for build an application show like in image. For the better graphics and performance wise. I want to know Flash for Flex is more suitable for this. In Flash ca we be able to build a grid kind of applications easily? I headed that Flex have the functions to handle grid and other things. Drag & scroll Zoom like feature. but am not sure able the graphics of flex. Is the components are customizable.. Please help me.

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  • Is it a good idea to create an STL iterator which is noncopyable?

    - by BillyONeal
    Most of the time, STL iterators are CopyConstructable, because several STL algorithms require this to improve performance, such as std::sort. However, I've been working on a pet project to wrap the FindXFile API (previously asked about), but the problem is it's impossible to implement a copyable iterator around this API. A find handle cannot be duplicated by any means -- DuplicateHandle specifically forbids passing handles to it. And if you just maintain a reference count to the find handle, then a single increment by any copy results in an increment of all copies -- clearly that is not what a copy constructed iterator is supposed to do. Since I can't satisfy the traditional copy constructible requirement for iterators here, is it even worth trying to create an "STL style" iterator? On one hand, creating some other enumeration method is going to not fall into normal STL conventions, but on the other, following STL conventions are going to confuse users of this iterator if they try to CopyConstruct it later. Which is the lesser of two evils?

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  • Struct in C, are they efficient?

    - by pygabriel
    I'm reading some C code like that: double function( int lena,double xa,double ya, double za, double *acoefs, ..., int lenb,double xb,double yb, double zb, double *bcoefs, ..., same for c, same for d ) This function is called in the code mor than 100.000 times so it's performance-critical. I'm trying to extend this code but I want to know if it's efficient or not (and how much this influences the speed) to encapsulate all the parameters in a struct like this struct PGTO { int len; double x,y,z ; double *acoefs } and then access the parameters in the function.

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  • Why my application ask for a codec to pla the MVI(.MOV) video files while i can play them on WMP and QuickTime?

    - by Daniel Lip
    I have an application i did some time ago when im loading the video file its ok when trying to play/use the file im getting the messageBox message say that its need a codec to use gspot or search the internet. Wehn im playing this files on my hard disk with Windows Media Play or either QuickTime there is no problems. The Video files for example name are: MVI_2483 in the file name properties i see its type: Quick Time Movie (.MOV) In my application im using DirectShowLib-2005.dll this is the class im using in my case to extract the video file im using it in my application to extract only lightnings from the video file name. In Form1 i have a button click event that just starting the action: private void button8_Click(object sender, EventArgs e) { viewToolStripMenuItem.Enabled = false; fileToolStripMenuItem.Enabled = false; button2.Enabled = false; label14.Visible = false; label15.Visible = false; label21.Visible = false; label22.Visible = false; label24.Visible = false; label25.Visible = false; ExtractAutomatic = true; DirectoryInfo info = new DirectoryInfo(_videoFile); string dirName = info.Name; automaticModeDirectory = dirName + "_Automatic"; subDirectoryName = _outputDir + "\\" + automaticModeDirectory; if (secondPass == true) { Start(true); } Start(false); } This is the function start in Form1: private void Start(bool secondpass) { setpicture(-1); if (Directory.Exists(_outputDir) && secondpass == false) { } else { Directory.CreateDirectory(_outputDir); } if (ExtractAutomatic == true) { string subDirectory_Automatic_Name = _outputDir + "\\" + automaticModeDirectory; Directory.CreateDirectory(subDirectory_Automatic_Name); f = new WmvAdapter(_videoFile, Path.Combine(subDirectory_Automatic_Name)); } else { string subDirectory_Manual_Name; if (Directory.Exists(subDirectoryName)) { subDirectory_Manual_Name = subDirectoryName; f = new WmvAdapter(_videoFile, Path.Combine(subDirectory_Manual_Name)); } else { subDirectory_Manual_Name = _outputDir + "\\" + averagesListTextFileDirectory + "_Manual"; Directory.CreateDirectory(subDirectory_Manual_Name); f = new WmvAdapter(_videoFile, Path.Combine(subDirectory_Manual_Name)); } } button1.Enabled = false; f.Secondpass = secondpass; f.FramesToSave = _fts; f.FrameCountAvailable += new WmvAdapter.FrameCountEventHandler(f_FrameCountAvailable); f.StatusChanged += new WmvAdapter.EventHandler(f_StatusChanged); f.ProgressChanged += new WmvAdapter.ProgressEventHandler(f_ProgressChanged); this.Text = "Processing Please Wait..."; label5.ForeColor = Color.Green; label5.Text = "Processing Please Wait"; button8.Enabled = false; button5.Enabled = false; label5.Visible = true; pictureBox1.Image = Lightnings_Extractor.Properties.Resources.Weather_Michmoret; Hrs = 0; //number of hours Min = 0; //number of Minutes Sec = 0; //number of Sec timeElapsed = 0; label10.Text = "00:00:00"; label11.Visible = false; label12.Visible = false; label9.Visible = false; label8.Visible = false; this.button1.Enabled = false; myTrackPanelss1.trackBar1.Enabled = false; this.checkBox2.Enabled = false; this.checkBox1.Enabled = false; numericUpDown1.Enabled = false; timer1.Start(); label2.Text = ""; label1.Visible = true; label2.Visible = true; label3.Visible = true; label4.Visible = true; f.Start(); } And this is the class wich is not my oqn class i just just defined it in some places wich making the problem: using System; using System.Diagnostics; using System.Drawing; using System.Drawing.Imaging; using System.IO; using System.Runtime.InteropServices; using DirectShowLib; using System.Collections.Generic; using Extracting_Frames; using System.Windows.Forms; namespace Polkan.DataSource { internal class WmvAdapter : ISampleGrabberCB, IDisposable { #region Fields_Properties_and_Events bool dis = false; int count = 0; const string fileName = @"d:\histogramValues.dat"; private IFilterGraph2 _filterGraph; private IMediaControl _mediaCtrl; private IMediaEvent _mediaEvent; private int _width; private int _height; private readonly string _outFolder; private int _frameId; //better use a custom EventHandler that passes the results of the action to the subscriber. public delegate void EventHandler(object sender, EventArgs e); public event EventHandler StatusChanged; public delegate void FrameCountEventHandler(object sender, FrameCountEventArgs e); public event FrameCountEventHandler FrameCountAvailable; public delegate void ProgressEventHandler(object sender, ProgressEventArgs e); public event ProgressEventHandler ProgressChanged; private IMediaSeeking _mSeek; private long _duration = 0; private long _avgFrameTime = 0; //just save the averages to a List (not to fs) public List<double> AveragesList { get; set; } public List<long> histogramValuesList; public bool Secondpass { get; set; } public List<int> FramesToSave { get; set; } #endregion #region Constructors and Destructors public WmvAdapter(string file, string outFolder) { _outFolder = outFolder; try { SetupGraph(file); } catch { Dispose(); MessageBox.Show("A codec is required to load this video file. Please use http://www.headbands.com/gspot/ or search the web for the correct codec"); } } ~WmvAdapter() { CloseInterfaces(); } #endregion public void Dispose() { CloseInterfaces(); } public void Start() { EstimateFrameCount(); int hr = _mediaCtrl.Run(); WaitUntilDone(); DsError.ThrowExceptionForHR(hr); } public void WaitUntilDone() { int hr; const int eAbort = unchecked((int)0x80004004); do { System.Windows.Forms.Application.DoEvents(); EventCode evCode; if (dis == true) { return; } hr = _mediaEvent.WaitForCompletion(100, out evCode); }while (hr == eAbort); DsError.ThrowExceptionForHR(hr); OnStatusChanged(); } //Edit: added events protected virtual void OnStatusChanged() { if (StatusChanged != null) StatusChanged(this, new EventArgs()); } protected virtual void OnFrameCountAvailable(long frameCount) { if (FrameCountAvailable != null) FrameCountAvailable(this, new FrameCountEventArgs() { FrameCount = frameCount }); } protected virtual void OnProgressChanged(int frameID) { if (ProgressChanged != null) ProgressChanged(this, new ProgressEventArgs() { FrameID = frameID }); } /// <summary> build the capture graph for grabber. </summary> private void SetupGraph(string file) { ISampleGrabber sampGrabber = null; IBaseFilter capFilter = null; IBaseFilter nullrenderer = null; _filterGraph = (IFilterGraph2)new FilterGraph(); _mediaCtrl = (IMediaControl)_filterGraph; _mediaEvent = (IMediaEvent)_filterGraph; _mSeek = (IMediaSeeking)_filterGraph; var mediaFilt = (IMediaFilter)_filterGraph; try { // Add the video source int hr = _filterGraph.AddSourceFilter(file, "Ds.NET FileFilter", out capFilter); DsError.ThrowExceptionForHR(hr); // Get the SampleGrabber interface sampGrabber = new SampleGrabber() as ISampleGrabber; var baseGrabFlt = sampGrabber as IBaseFilter; ConfigureSampleGrabber(sampGrabber); // Add the frame grabber to the graph hr = _filterGraph.AddFilter(baseGrabFlt, "Ds.NET Grabber"); DsError.ThrowExceptionForHR(hr); // --------------------------------- // Connect the file filter to the sample grabber // Hopefully this will be the video pin, we could check by reading it's mediatype IPin iPinOut = DsFindPin.ByDirection(capFilter, PinDirection.Output, 0); // Get the input pin from the sample grabber IPin iPinIn = DsFindPin.ByDirection(baseGrabFlt, PinDirection.Input, 0); hr = _filterGraph.Connect(iPinOut, iPinIn); DsError.ThrowExceptionForHR(hr); // Add the null renderer to the graph nullrenderer = new NullRenderer() as IBaseFilter; hr = _filterGraph.AddFilter(nullrenderer, "Null renderer"); DsError.ThrowExceptionForHR(hr); // --------------------------------- // Connect the sample grabber to the null renderer iPinOut = DsFindPin.ByDirection(baseGrabFlt, PinDirection.Output, 0); iPinIn = DsFindPin.ByDirection(nullrenderer, PinDirection.Input, 0); hr = _filterGraph.Connect(iPinOut, iPinIn); DsError.ThrowExceptionForHR(hr); // Turn off the clock. This causes the frames to be sent // thru the graph as fast as possible hr = mediaFilt.SetSyncSource(null); DsError.ThrowExceptionForHR(hr); // Read and cache the image sizes SaveSizeInfo(sampGrabber); //Edit: get the duration hr = _mSeek.GetDuration(out _duration); DsError.ThrowExceptionForHR(hr); } finally { if (capFilter != null) { Marshal.ReleaseComObject(capFilter); } if (sampGrabber != null) { Marshal.ReleaseComObject(sampGrabber); } if (nullrenderer != null) { Marshal.ReleaseComObject(nullrenderer); } GC.Collect(); } } private void EstimateFrameCount() { try { //1sec / averageFrameTime double fr = 10000000.0 / _avgFrameTime; double frameCount = fr * (_duration / 10000000.0); OnFrameCountAvailable((long)frameCount); } catch { } } public double framesCounts() { double fr = 10000000.0 / _avgFrameTime; double frameCount = fr * (_duration / 10000000.0); return frameCount; } private void SaveSizeInfo(ISampleGrabber sampGrabber) { // Get the media type from the SampleGrabber var media = new AMMediaType(); int hr = sampGrabber.GetConnectedMediaType(media); DsError.ThrowExceptionForHR(hr); if ((media.formatType != FormatType.VideoInfo) || (media.formatPtr == IntPtr.Zero)) { throw new NotSupportedException("Unknown Grabber Media Format"); } // Grab the size info var videoInfoHeader = (VideoInfoHeader)Marshal.PtrToStructure(media.formatPtr, typeof(VideoInfoHeader)); _width = videoInfoHeader.BmiHeader.Width; _height = videoInfoHeader.BmiHeader.Height; //Edit: get framerate _avgFrameTime = videoInfoHeader.AvgTimePerFrame; DsUtils.FreeAMMediaType(media); GC.Collect(); } private void ConfigureSampleGrabber(ISampleGrabber sampGrabber) { var media = new AMMediaType { majorType = MediaType.Video, subType = MediaSubType.RGB24, formatType = FormatType.VideoInfo }; int hr = sampGrabber.SetMediaType(media); DsError.ThrowExceptionForHR(hr); DsUtils.FreeAMMediaType(media); GC.Collect(); hr = sampGrabber.SetCallback(this, 1); DsError.ThrowExceptionForHR(hr); } private void CloseInterfaces() { try { if (_mediaCtrl != null) { _mediaCtrl.Stop(); _mediaCtrl = null; dis = true; } } catch (Exception ex) { Debug.WriteLine(ex); } if (_filterGraph != null) { Marshal.ReleaseComObject(_filterGraph); _filterGraph = null; } GC.Collect(); } int ISampleGrabberCB.SampleCB(double sampleTime, IMediaSample pSample) { Marshal.ReleaseComObject(pSample); return 0; } int ISampleGrabberCB.BufferCB(double sampleTime, IntPtr pBuffer, int bufferLen) { if (Form1.ExtractAutomatic == true) { using (var bitmap = new Bitmap(_width, _height, _width * 3, PixelFormat.Format24bppRgb, pBuffer)) { if (!this.Secondpass) { long[] HistogramValues = Form1.GetHistogram(bitmap); long t = Form1.GetTopLumAmount(HistogramValues, 1000); Form1.averagesTest.Add(t); } else { //this is the changed part if (_frameId > 0) { if (Form1.averagesTest[_frameId] / 1000.0 - Form1.averagesTest[_frameId - 1] / 1000.0 > 150.0) { count = 6; } if (count > 0) { bitmap.RotateFlip(RotateFlipType.Rotate180FlipX); bitmap.Save(Path.Combine(_outFolder, _frameId.ToString("D6") + ".bmp")); count --; } } } _frameId++; //let only report each 100 frames for performance if (_frameId % 100 == 0) OnProgressChanged(_frameId); } } else { using (var bitmap = new Bitmap(_width, _height, _width * 3, PixelFormat.Format24bppRgb, pBuffer)) { if (!this.Secondpass) { //get avg double average = GetAveragePixelValue(bitmap); if (AveragesList == null) AveragesList = new List<double>(); //save avg AveragesList.Add(average); //***************************\\ // for (int i = 0; i < (int)framesCounts(); i++) // { // get histogram values long[] HistogramValues = Form1.GetHistogram(bitmap); if (histogramValuesList == null) histogramValuesList = new List<long>(256); histogramValuesList.AddRange(HistogramValues); //***************************\\ //} } else { if (FramesToSave != null && FramesToSave.Contains(_frameId)) { bitmap.RotateFlip(RotateFlipType.Rotate180FlipX); bitmap.Save(Path.Combine(_outFolder, _frameId.ToString("D6") + ".bmp")); // get histogram values long[] HistogramValues = Form1.GetHistogram(bitmap); if (histogramValuesList == null) histogramValuesList = new List<long>(256); histogramValuesList.AddRange(HistogramValues); using (BinaryWriter binWriter = new BinaryWriter(File.Open(fileName, FileMode.Create))) { for (int i = 0; i < histogramValuesList.Count; i++) { binWriter.Write(histogramValuesList[(int)i]); } binWriter.Close(); } } } _frameId++; //let only report each 100 frames for performance if (_frameId % 100 == 0) OnProgressChanged(_frameId); } } return 0; } /* int ISampleGrabberCB.SampleCB(double sampleTime, IMediaSample pSample) { Marshal.ReleaseComObject(pSample); return 0; } int ISampleGrabberCB.BufferCB(double sampleTime, IntPtr pBuffer, int bufferLen) { using (var bitmap = new Bitmap(_width, _height, _width * 3, PixelFormat.Format24bppRgb, pBuffer)) { if (!this.Secondpass) { //get avg double average = GetAveragePixelValue(bitmap); if (AveragesList == null) AveragesList = new List<double>(); //save avg AveragesList.Add(average); //***************************\\ // for (int i = 0; i < (int)framesCounts(); i++) // { // get histogram values long[] HistogramValues = Form1.GetHistogram(bitmap); if (histogramValuesList == null) histogramValuesList = new List<long>(256); histogramValuesList.AddRange(HistogramValues); long t = Form1.GetTopLumAmount(HistogramValues, 1000); //***************************\\ Form1.averagesTest.Add(t); // to add this list to a text file or binary file and read the averages from the file when its is Secondpass !!!!! //} } else { if (FramesToSave != null && FramesToSave.Contains(_frameId)) { bitmap.RotateFlip(RotateFlipType.Rotate180FlipX); bitmap.Save(Path.Combine(_outFolder, _frameId.ToString("D6") + ".bmp")); // get histogram values long[] HistogramValues = Form1.GetHistogram(bitmap); if (histogramValuesList == null) histogramValuesList = new List<long>(256); histogramValuesList.AddRange(HistogramValues); using (BinaryWriter binWriter = new BinaryWriter(File.Open(fileName, FileMode.Create))) { for (int i = 0; i < histogramValuesList.Count; i++) { binWriter.Write(histogramValuesList[(int)i]); } binWriter.Close(); } } for (int x = 1; x < Form1.averagesTest.Count; x++) { double fff = Form1.averagesTest[x] / 1000.0 - Form1.averagesTest[x - 1] / 1000.0; if (Form1.averagesTest[x] / 1000.0 - Form1.averagesTest[x - 1] / 1000.0 > 180.0) { bitmap.RotateFlip(RotateFlipType.Rotate180FlipX); bitmap.Save(Path.Combine(_outFolder, _frameId.ToString("D6") + ".bmp")); _frameId++; } } } _frameId++; //let only report each 100 frames for performance if (_frameId % 100 == 0) OnProgressChanged(_frameId); } return 0; }*/ private unsafe double GetAveragePixelValue(Bitmap bmp) { BitmapData bmData = null; try { bmData = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb); int stride = bmData.Stride; IntPtr scan0 = bmData.Scan0; int w = bmData.Width; int h = bmData.Height; double sum = 0; long pixels = bmp.Width * bmp.Height; byte* p = (byte*)scan0.ToPointer(); for (int y = 0; y < h; y++) { p = (byte*)scan0.ToPointer(); p += y * stride; for (int x = 0; x < w; x++) { double i = ((double)p[0] + p[1] + p[2]) / 3.0; sum += i; p += 3; } //no offset incrementation needed when getting //the pointer at the start of each row } bmp.UnlockBits(bmData); double result = sum / (double)pixels; return result; } catch { try { bmp.UnlockBits(bmData); } catch { } } return -1; } } public class FrameCountEventArgs { public long FrameCount { get; set; } } public class ProgressEventArgs { public int FrameID { get; set; } } } I remember i had this codec problem/s before and i installed the codec/'s that were needed but in this case both quick time and windows media player can play the video files so why the application cant detect and find the codec/'s on my computer ? Gspot say that the codec is AVC1 but again wmp and quicktime play the video files no problems. The video files are from my digital camera !

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  • How do I get the name of the newest file via the Terminal?

    - by Alec
    I'm trying to create a macro for Keyboard Maestro for OS X doing the following: Get name of newest file in a directory on my disk based on date created; Paste the text "newest file: " plus the name of the newest file. One of its options is to "Execute a shell script", so I thought that would do it for 1. After Googling around a bit I came up with this: cd /path/to/directory/ ls -t | head -n1 This sorts it right, and returns the first filename. However, it also seems to includes a line break, which I do not want. As for 2: I can output the text "newest file: " with a different action in the app, and paste the filename behind that. But I'm wondering if you can't return "random text" + the outcome of the ls command. So my question is: can I do this only using the ls command? And how do I get just the name of the latest file without any linebreaks or returns?

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  • Parametrize the WHERE clause?

    - by ControlFlow
    Hi, stackoverflow! I'm need to write an stored procedure for SQL Server 2008 for performing some huge select query and I need filter it results with specifying filtering type via procedure's parameters (parameterize where clause). I found some solutions like this: create table Foo( id bigint, code char, name nvarchar(max)) go insert into Foo values (1,'a','aaa'), (2,'b','bbb'), (3,'c','ccc') go create procedure Bar @FilterType nvarchar(max), @FilterValue nvarchar(max) as begin select * from Foo as f where case @FilterType when 'by_id' then f.id when 'by_code' then f.code when 'by_name' then f.name end = case @FilterType when 'by_id' then cast(@FilterValue as bigint) when 'by_code' then cast(@FilterValue as char) when 'by_name' then @FilterValue end end go exec Bar 'by_id', '1'; exec Bar 'by_code', 'b'; exec Bar 'by_name', 'ccc'; But it doesn't work when the columns has different data types... It's possible to cast all the columns to nvarchar(max) and compare they as strings, but I think it will cause a performance degradation... Is it possible to parameterize where clause in stored procedure without using things like EXEC sp_executesql (dynamic SQL and etc.)?

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  • GPU YUV to RGB. Worth the effort?

    - by Jaime Pardos
    Hello, I have to convert several full PAL videos (720x576@25) from YUV 4:2:2 to RGB, in real time, and probably a custom resize for each. I have thought of using the GPU, as I have seen some example that does just this (except that it's 4:4:4 so the bpp is the same in source and destiny)-- http://www.fourcc.org/source/YUV420P-OpenGL-GLSLang.c However, I don't have any experience with using GPU's and I'm not sure of what can be done. The example, as I understand it, just converts the video frame to YUV and displays it in the screen. Is it possible to get the processed frame instead? Would it be worth the effort to send it to the GPU, get it transformed, and sending it again to main memory, or would it kill performance? Being a bit platform-specific, assuming I work on windows, is it possible to get an OpenGL or DirectDraw surface from a window so the GPU can draw directly to it?

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  • Critiquing my first Python script

    - by tipu
    A little bit of background: I'm building an inverted index for a search engine. I was originally using PHP, but because of the amount of times I needed to write to disk, I wanted to make a threaded indexer. There's a problem with that because PHP is not thread safe. I then tried Java, but I ended up with at least 20 try catch blocks because of the JSON data structure I was using and working with files. The code was just too big and ugly. Then I figured I should pick up some Python because it's flexible like PHP but also thread safe. Though I'm open to all criticism, what I'd like to learn is the shortcuts that the Python language/library provides that I skipped over. This is a PHP-afide Python script because all I really did was translate the PHP script line by line to what I thought was it's Python equivalent. Thanks. http://pastebin.com/xrg7rf9w

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  • Best practices to build a highly configurable software product.

    - by Kabeer
    Hello. I am working on a software product that can substantially change behavior based on the configuration & meta-data supplied. I would like to know best practices to architect / build a highly configurable software product. Considering that there are substantial number of configuration parameters, I'd like to look at something that will not affect the performance before I look at dependency injection. My platform is .Net ... I seek recommendations on architecture / design and implementations fronts.

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  • PostgreSQL 8.3 data types: xml vs varchar

    - by Sejanus
    There's xml data type in Postgres, I never used it before so I'd like to hear opinions. Downsides and upsides vs using regular varchar (or Text) column to store xml. The text I'm going to store is xml, well-formed, UTF-8. No need to search by it (I've read searching by xml is slow). This XML actually is data prepared for PDF generation with Apache FOP. XML can be generated dynamically from data found elsewhere (other Postgres tables), it's stored as is only so that I won't need to generate it twice. Kinda backup#2 for already generated PDF documents. Anything else to know? Good practices, performance, maintenance, etc?

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  • I want to version control my entire slice

    - by Tom
    I'm renting a slice (i.e., a VPS) from Slicehost. I've a spent a day or two filling up /usr with my favorite packages, /etc with configs and init scripts, and so on. Now I want to: save this whole setup somewhere (e.g., to load onto another machine). see what changes I've made to which files revert changes, tag revisions, and all that other good version control stuff Saving a disk image gives me (1), but not (2) and (3). Using Subversion (svn import / svn://someotherhost) might give me all three, but I expect problems if I actually try to check a project out into / and maintain .svn directories in root-owned areas. And to load my setup onto a fresh slice, I'd need to install an svn client on it first. Is there a good way to do what I want to do?

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  • [OpenGL] I'm having an issue to use GLshort for representing Vertex, and Normal.

    - by Xylopia
    As my project gets close to optimization stage, I notice that reducing Vertex Metadata could vastly improve the performance of 3D rendering. Eventually, I've dearly searched around and have found following advices from stackoverflow. Using GL_SHORT instead of GL_FLOAT in an OpenGL ES vertex array How do you represent a normal or texture coordinate using GLshorts? Advice on speeding up OpenGL ES 1.1 on the iPhone Simple experiments show that switching from "FLOAT" to "SHORT" for vertex and normal isn't tough, but what troubles me is when you're to scale back verticies to their original size (with glScalef), normals are multiplied by the reciprocal of the scale. Then how do you use "short" for both vertex and normal at the same time? I've been trying this and that for about a full day, but I could only go for "float vertex w/ byte normal" or "short vertex w/ float normal" so far. Your help would be truly appreciated.

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  • Throughput measurements

    - by dotsid
    I wrote simple load testing tool for testing performance of Java modules. One problem I faced is algorithm of throughput measurements. Tests are executed in several thread (client configure how much times test should be repeated), and execution time is logged. So, when tests are finished we have following history: 4 test executions 2 threads 36ms overall time - idle * test execution 5ms 9ms 4ms 13ms T1 |-*****-*********-****-*************-| 3ms 6ms 7ms 11ms T2 |-***-******-*******-***********-----| <-----------------36ms---------------> For the moment I calculate throughput (per second) in a following way: 1000 / overallTime * threadCount. But there is problem. What if one thread will complete it's own tests more quickly (for whatever reason): 3ms 3ms 3ms 3ms T1 |-***-***-***-***----------------| 3ms 6ms 7ms 11ms T2 |-***-******-*******-***********-| <--------------32ms--------------> In this case actual throughput is much better because of measured throughput is bounded by the most slow thread. So, my question is how should I measure throughput of code execution in multithreaded environment.

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  • What design considerations should one take to receive text and multiple attachments via web?

    - by ramesh.nagul
    I am developing a web application to accept a bunch of text and attachments (1 or more) via email, web and other methods. I am planning to build a single interface, mostly a web service to accept this content. What design considerations should I make? I am building the app using ASP.NET MVC 2. Should the attachments be saved to disk or in the database? Should the unified single interface be a web service? Pros and cons to using web services to upload files

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  • Are we asking too much of transactional memory?

    - by Carl Seleborg
    I've been reading up a lot about transactional memory lately. There is a bit of hype around TM, so a lot of people are enthusiastic about it, and it does provide solutions for painful problems with locking, but you regularly also see complaints: You can't do I/O You have to write your atomic sections so they can run several times (be careful with your local variables!) Software transactional memory offers poor performance [Insert your pet peeve here] I understand these concerns: more often than not, you find articles about STMs that only run on some particular hardware that supports some really nifty atomic operation (like LL/SC), or it has to be supported by some imaginary compiler, or it requires that all accesses to memory be transactional, it introduces type constraints monad-style, etc. And above all: these are real problems. This has lead me to ask myself: what speaks against local use of transactional memory as a replacement for locks? Would this already bring enough value, or must transactional memory be used all over the place if used at all?

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