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Is the Leptonica implementation of 'Modified Median Cut' not using the median at all?

- by TheCodeJunkie

I'm playing around a bit with image processing and decided to read up on how color quantization worked and after a bit of reading I found the Modified Median Cut Quantization algorithm. I've been reading the code of the C implementation in Leptonica library and came across something I thought was a bit odd. Now I want to stress that I am far from an expert in this area, not am I a math-head, so I am predicting that this all comes down to me not understanding all of it and not that the implementation of the algorithm is wrong at all. The algorithm states that the vbox should be split along the lagest axis and that it should be split using the following logic The largest axis is divided by locating the bin with the median pixel (by population), selecting the longer side, and dividing in the center of that side. We could have simply put the bin with the median pixel in the shorter side, but in the early stages of subdivision, this tends to put low density clusters (that are not considered in the subdivision) in the same vbox as part of a high density cluster that will outvote it in median vbox color, even with future median-based subdivisions. The algorithm used here is particularly important in early subdivisions, and 3is useful for giving visible but low population color clusters their own vbox. This has little effect on the subdivision of high density clusters, which ultimately will have roughly equal population in their vboxes. For the sake of the argument, let's assume that we have a vbox that we are in the process of splitting and that the red axis is the largest. In the Leptonica algorithm, on line 01297, the code appears to do the following Iterate over all the possible green and blue variations of the red color For each iteration it adds to the total number of pixels (population) it's found along the red axis For each red color it sum up the population of the current red and the previous ones, thus storing an accumulated value, for each red note: when I say 'red' I mean each point along the axis that is covered by the iteration, the actual color may not be red but contains a certain amount of red So for the sake of illustration, assume we have 9 "bins" along the red axis and that they have the following populations 4 8 20 16 1 9 12 8 8 After the iteration of all red bins, the partialsum array will contain the following count for the bins mentioned above 4 12 32 48 49 58 70 78 86 And total would have a value of 86 Once that's done it's time to perform the actual median cut and for the red axis this is performed on line 01346 It iterates over bins and check they accumulated sum. And here's the part that throws me of from the description of the algorithm. It looks for the first bin that has a value that is greater than total/2 Wouldn't total/2 mean that it is looking for a bin that has a value that is greater than the average value and not the median ? The median for the above bins would be 49 The use of 43 or 49 could potentially have a huge impact on how the boxes are split, even though the algorithm then proceeds by moving to the center of the larger side of where the matched value was.. Another thing that puzzles me a bit is that the paper specified that the bin with the median value should be located, but does not mention how to proceed if there are an even number of bins.. the median would be the result of (a+b)/2 and it's not guaranteed that any of the bins contains that population count. So this is what makes me thing that there are some approximations going on that are negligible because of how the split actually takes part at the center of the larger side of the selected bin. Sorry if it got a bit long winded, but I wanted to be as thoroughas I could because it's been driving me nuts for a couple of days now ;)

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How can I get image data from QTKit without color or gamma correction in Snow Leopard?

- by Nick Haddad

Since Snow Leopard, QTKit is now returning color corrected image data from functions like QTMovies frameImageAtTime:withAttributes:error:. Given an uncompressed AVI file, the same image data is displayed with larger pixel values in Snow Leopard vs. Leopard. Currently I'm using frameImageAtTime to get an NSImage, then ask for the tiffRepresentation of that image. After doing this, pixel values are slightly higher in Snow Leopard. For example, a file with the following pixel value in Leopard: [0 180 0] Now has a pixel value like: [0 192 0] Is there any way to ask a QTMovie for video frames that are not color corrected? Should I be asking for a CGImageRef, CIImage, or CVPixelBufferRef instead? Is there a way to disable color correction altogether prior to reading in the video files? I've attempted to work around this issue by drawing into a NSBitmapImageRep with the NSCalibratedColroSpace, but that only gets my part of the way there: // Create a movie NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys : nsFileName, QTMovieFileNameAttribute, [NSNumber numberWithBool:NO], QTMovieOpenAsyncOKAttribute, [NSNumber numberWithBool:NO], QTMovieLoopsAttribute, [NSNumber numberWithBool:NO], QTMovieLoopsBackAndForthAttribute, (id)nil]; _theMovie = [[QTMovie alloc] initWithAttributes:dict error:&error]; // .... NSMutableDictionary *imageAttributes = [NSMutableDictionary dictionary]; [imageAttributes setObject:QTMovieFrameImageTypeNSImage forKey:QTMovieFrameImageType]; [imageAttributes setObject:[NSArray arrayWithObject:@"NSBitmapImageRep"] forKey: QTMovieFrameImageRepresentationsType]; [imageAttributes setObject:[NSNumber numberWithBool:YES] forKey:QTMovieFrameImageHighQuality]; NSError* err = nil; NSImage* image = (NSImage*)[_theMovie frameImageAtTime:frameTime withAttributes:imageAttributes error:&err]; // copy NSImage into an NSBitmapImageRep (Objective-C) NSBitmapImageRep* bitmap = [[image representations] objectAtIndex:0]; // Draw into a colorspace we know about NSBitmapImageRep *bitmapWhoseFormatIKnow = [[NSBitmapImageRep alloc] initWithBitmapDataPlanes:NULL pixelsWide:getWidth() pixelsHigh:getHeight() bitsPerSample:8 samplesPerPixel:4 hasAlpha:YES isPlanar:NO colorSpaceName:NSCalibratedRGBColorSpace bitmapFormat:0 bytesPerRow:(getWidth() * 4) bitsPerPixel:32]; [NSGraphicsContext saveGraphicsState]; [NSGraphicsContext setCurrentContext:[NSGraphicsContext graphicsContextWithBitmapImageRep:bitmapWhoseFormatIKnow]]; [bitmap draw]; [NSGraphicsContext restoreGraphicsState]; This does convert back to a 'Non color corrected' colorspace, but the color values NOT are exactly the same as what is stored in the Uncompressed AVI files we are testing with. Also this is much less efficient because it is converting from RGB - "Device RGB" - RGB. Also, I am working in a 64-bit application, so dropping down to the Quicktime-C API is not an option. Thanks for your help.

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Relational Database pioneer Chris Date is giving a seminar 13th/14th May Edinburgh on "SQL and Relat

- by tonyrogerson

One of the pioneers of the Relational Database, Chris Date is giving a 2 day seminar in Edinburgh (13th and 14th May 2010) based around his new book "SQL and Relational Theory - How to Write Accurate SQL Code" which if you don't already have I'd say is a must buy. When I first saw this and what he will cover I thought, oh yer - this is going to cost the earth, well it doesn't - its £750 for the two days and there are discounts available for multiple bookings, being a member...(read more)

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Download and Share Visual Studio Color Schemes

As developers we often spend a large part of our day staring at code within Visual Studio. If you are like me, after awhile the default VS text color scheme starts to get a little boring. The good news is that Visual Studio allows you to completely customize the editor background and text colors to whatever you want allowing you to tweak them to create the experience that is just right for your eyes and personality. You can then optionally export/import your color scheme preferences...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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Issue with CSS font color in Webkit in Lion (#444 looks darker than #333)

- by Andrea

I have a strange issue with Safari and Chrome Mac (19.0.1084.54) in OS X Lion. Here it is, very simply put: When I display it in a Webkit browser, text set in Helvetica Neue and color Hex #444 looks a little bolder, and therefore darker, than the same text with an Hex color value of #333. This does not happen at all in Snow Leopard with the exact same browsers (same version). Happens on any website I tried, so I know it's not something related to the CSS of my website. I tried to change it live through the Inspector and it really shows up. I made a little screencast to explain it better: http://goo.gl/prQAn (.mov - ~60MB) Anyone has ever experienced something like that?

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How to change tooltip background color in Unity?

- by kayahr

In a lot of applications the tooltips are just plain ugly (White text on black background, way too much contrast) or even unreadable (black or dark blue text (Hyperlinks) on black background). I want to change the background color of the tooltips to some medium gray or even some yellow or something like that, maybe even something semi-transparent. Here is a screenshot of Eclipse which displays some source code in a tool tip with black text on black background: Switching to a different theme (Something other than Ambiance or Radiance) helps but I like Ambiance and I want to keep it. It's just this darn tooltip color which is absolutely unacceptable. I found several solutions for older Ubuntu versions but they no longer work with Unity in Ubuntu 11.10 because I can't find any function to customize the Ambiance or Radiance theme. So how do I do that in the current Ubuntu version?

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Vista/7: How to get glass color?

- by Ian Boyd

How do you use DwmGetColorizationColor? The documentation says it returns two values: a 32-bit 0xAARRGGBB containing the color used for glass composition a boolean parameter that is true "if the color is an opaque blend" (whatever that means) Here's a color that i like, a nice puke green: You can notice the color is greeny, and the translucent title bar (against a white background) shows the snot color very clearly: i try to get the color from Windows: DwmGetColorizationColor(dwCcolorization, bIsOpaqueBlend); And i get dwColorization: 0x0D0A0F04 bIsOpaqueBlend: false According to the documentation this value is of the format AARRGGBB, and so contains: AA: 0x0D (13) RR: 0x0A (10) GG: 0x0F (15) BB: 0x04 (4) This supposedly means that the color is (10, 15, 4), with an opacity of ~5.1%. But if you actually look at this RGB value, it's nowhere near my desired snot green. Here is (10, 15, 4) with zero opacity (the original color), and (10,15,4) with 5% opacity against a white/checkerboard background: So the question is: How to get glass color in Windows Vista/7? i tried using DwmGetColorizationColor, but that doesn't work very well. A person with same problem, but a nicer shiny picture to attract you squirrels: So, it boils down to – DwmGetColorizationColor is completely unusable for applications attempting to apply the current color onto an opaque surface. i love this guy's screenshots much better than mine. Using his screenshots as a template, i made up a few more sparklies: For the last two screenshots, the alpha blended chip is a true partially transparent PNG, blending to your browser's background. Cool! (i'm such a geek) Edit 2: Had to arrange them in rainbow color. (i'm such a geek) Edit 3: Well now i of course have to add Yellow. Undocumented/Unsupported/Fragile Workarounds There is an undocumented export from DwmApi.dll at entry point 137, which we'll call DwmGetColorizationParameters: HRESULT GetColorizationParameters_Undocumented(out DWMCOLORIZATIONPARAMS params); struct DWMCOLORIZATIONPARAMS { public UInt32 ColorizationColor; public UInt32 ColorizationAfterglow; public UInt32 ColorizationColorBalance; public UInt32 ColorizationAfterglowBalance; public UInt32 ColorizationBlurBalance; public UInt32 ColorizationGlassReflectionIntensity; public UInt32 ColorizationOpaqueBlend; } We're interested in the first parameter: ColorizationColor. We can also read the value out of the registry: HKEY_CURRENT_USER\Software\Microsoft\Windows\DWM ColorizationColor: REG_DWORD = 0x6614A600 So you pick your poison of creating appcompat issues. You can rely on an undocumented API (which is bad, bad, bad, and can go away at any time) use an undocumented registry key (which is also bad, and can go away at any time) See also Is there a list of valid parameter combinations for GetThemeColor / Visual Styles API How does Windows change Aero Glass color? DWM - Colorization Color Handling Using DWMGetColorizationColor Retrieving Aero Glass base color for opaque surface rendering i've been wanting to ask this question for over a year now. i always knew that it's impossible to answer, and that the only way to get anyone to actually pay attention is to have colorful screenshots; developers are attracted to shiny things. But on the downside it means i had to put all kinds of work into making the lures.

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How to change the sprite colors

- by Mr_Qqn

In my rhythm game, I have a note object which can be of different colors depending on the note chart. I could use a sprite sheet with all the different color variations I use, but I would prefer to parametrize this. (For information, a note sprite is compound with one main color, for example a red note has only red, light red and dark red.) So, how to change the colors of a sprite basing on a new color ? I'm working with opengl, but any algorithm or math explanation will do. :) Thanks

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How can I further optimize this color difference function?

- by aLfa

I have made this function to calculate color differences in the CIE Lab colorspace, but it lacks speed. Since I'm not a Java expert, I wonder if any Java guru around has some tips that can improve the speed here. The code is based on the matlab function mentioned in the comment block. /** * Compute the CIEDE2000 color-difference between the sample color with * CIELab coordinates 'sample' and a standard color with CIELab coordinates * 'std' * * Based on the article: * "The CIEDE2000 Color-Difference Formula: Implementation Notes, * Supplementary Test Data, and Mathematical Observations,", G. Sharma, * W. Wu, E. N. Dalal, submitted to Color Research and Application, * January 2004. * available at http://www.ece.rochester.edu/~gsharma/ciede2000/ */ public static double deltaE2000(double[] lab1, double[] lab2) { double L1 = lab1[0]; double a1 = lab1[1]; double b1 = lab1[2]; double L2 = lab2[0]; double a2 = lab2[1]; double b2 = lab2[2]; // Cab = sqrt(a^2 + b^2) double Cab1 = Math.sqrt(a1 * a1 + b1 * b1); double Cab2 = Math.sqrt(a2 * a2 + b2 * b2); // CabAvg = (Cab1 + Cab2) / 2 double CabAvg = (Cab1 + Cab2) / 2; // G = 1 + (1 - sqrt((CabAvg^7) / (CabAvg^7 + 25^7))) / 2 double CabAvg7 = Math.pow(CabAvg, 7); double G = 1 + (1 - Math.sqrt(CabAvg7 / (CabAvg7 + 6103515625.0))) / 2; // ap = G * a double ap1 = G * a1; double ap2 = G * a2; // Cp = sqrt(ap^2 + b^2) double Cp1 = Math.sqrt(ap1 * ap1 + b1 * b1); double Cp2 = Math.sqrt(ap2 * ap2 + b2 * b2); // CpProd = (Cp1 * Cp2) double CpProd = Cp1 * Cp2; // hp1 = atan2(b1, ap1) double hp1 = Math.atan2(b1, ap1); // ensure hue is between 0 and 2pi if (hp1 < 0) { // hp1 = hp1 + 2pi hp1 += 6.283185307179586476925286766559; } // hp2 = atan2(b2, ap2) double hp2 = Math.atan2(b2, ap2); // ensure hue is between 0 and 2pi if (hp2 < 0) { // hp2 = hp2 + 2pi hp2 += 6.283185307179586476925286766559; } // dL = L2 - L1 double dL = L2 - L1; // dC = Cp2 - Cp1 double dC = Cp2 - Cp1; // computation of hue difference double dhp = 0.0; // set hue difference to zero if the product of chromas is zero if (CpProd != 0) { // dhp = hp2 - hp1 dhp = hp2 - hp1; if (dhp > Math.PI) { // dhp = dhp - 2pi dhp -= 6.283185307179586476925286766559; } else if (dhp < -Math.PI) { // dhp = dhp + 2pi dhp += 6.283185307179586476925286766559; } } // dH = 2 * sqrt(CpProd) * sin(dhp / 2) double dH = 2 * Math.sqrt(CpProd) * Math.sin(dhp / 2); // weighting functions // Lp = (L1 + L2) / 2 - 50 double Lp = (L1 + L2) / 2 - 50; // Cp = (Cp1 + Cp2) / 2 double Cp = (Cp1 + Cp2) / 2; // average hue computation // hp = (hp1 + hp2) / 2 double hp = (hp1 + hp2) / 2; // identify positions for which abs hue diff exceeds 180 degrees if (Math.abs(hp1 - hp2) > Math.PI) { // hp = hp - pi hp -= Math.PI; } // ensure hue is between 0 and 2pi if (hp < 0) { // hp = hp + 2pi hp += 6.283185307179586476925286766559; } // LpSqr = Lp^2 double LpSqr = Lp * Lp; // Sl = 1 + 0.015 * LpSqr / sqrt(20 + LpSqr) double Sl = 1 + 0.015 * LpSqr / Math.sqrt(20 + LpSqr); // Sc = 1 + 0.045 * Cp double Sc = 1 + 0.045 * Cp; // T = 1 - 0.17 * cos(hp - pi / 6) + // + 0.24 * cos(2 * hp) + // + 0.32 * cos(3 * hp + pi / 30) - // - 0.20 * cos(4 * hp - 63 * pi / 180) double hphp = hp + hp; double T = 1 - 0.17 * Math.cos(hp - 0.52359877559829887307710723054658) + 0.24 * Math.cos(hphp) + 0.32 * Math.cos(hphp + hp + 0.10471975511965977461542144610932) - 0.20 * Math.cos(hphp + hphp - 1.0995574287564276334619251841478); // Sh = 1 + 0.015 * Cp * T double Sh = 1 + 0.015 * Cp * T; // deltaThetaRad = (pi / 3) * e^-(36 / (5 * pi) * hp - 11)^2 double powerBase = hp - 4.799655442984406; double deltaThetaRad = 1.0471975511965977461542144610932 * Math.exp(-5.25249016001879 * powerBase * powerBase); // Rc = 2 * sqrt((Cp^7) / (Cp^7 + 25^7)) double Cp7 = Math.pow(Cp, 7); double Rc = 2 * Math.sqrt(Cp7 / (Cp7 + 6103515625.0)); // RT = -sin(delthetarad) * Rc double RT = -Math.sin(deltaThetaRad) * Rc; // de00 = sqrt((dL / Sl)^2 + (dC / Sc)^2 + (dH / Sh)^2 + RT * (dC / Sc) * (dH / Sh)) double dLSl = dL / Sl; double dCSc = dC / Sc; double dHSh = dH / Sh; return Math.sqrt(dLSl * dLSl + dCSc * dCSc + dHSh * dHSh + RT * dCSc * dHSh); }

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How to change text color for link in tr element with CSS

- by mathee

I'd like to change the background and text color when the mouse hovers over a row in a table: tr { background-color:#FFF; color:#000; } tr:hover { background-color:#000; color:#FFF; } This works if there aren't any links in the tr elements, but when there are, the link color remains black (because of a { color: #000; }?). How do I specify in the CSS that links in the tr element should change color when the mouse hovers over the tr?

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Does style="color: #FFF;" render as #F0F0F0 or #FFFFFF?

- by Dolph Mathews

When defining colors using "shorthand hexidecimal" (style="color: #FFF;"), is there a defined method for expanding the shorthand? (style="color: #F0F0F0;" or style="color: #FFFFFF;") Do all browsers use the same expansion method? Is this behavior by specification (if so, where is it defined)? Does the expansion method perhaps vary between CSS 1/2/3? I've observed that "most browsers" expand to #FFFFFF. Are there any other places where this shorthand notation is allowed, but the expansion method is different? I've always avoided using shorthand hex, because I've never known the answers to these questions...

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Where can I find a jQuery color animation plugin?

- by George Edison

I need an up-to-date jQuery color animation plugin that works in IE 8. I tried using the one at http://plugins.jquery.com/project/color but it causes errors like "Invalid property value." in the following line of code from color.js: fx.elem.style[attr] = "rgb(" + [ Math.max(Math.min( parseInt((fx.pos * (fx.end[0] - fx.start[0])) + fx.start[0]), 255), 0), Math.max(Math.min( parseInt((fx.pos * (fx.end[1] - fx.start[1])) + fx.start[1]), 255), 0), Math.max(Math.min( parseInt((fx.pos * (fx.end[2] - fx.start[2])) + fx.start[2]), 255), 0) ].join(",") + ")"; Where can I get something that works? By the way, I really hate IE, if that helps.

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Processing Kinect v2 Color Streams in Parallel

- by Chris Gardner

Originally posted on: http://geekswithblogs.net/freestylecoding/archive/2014/08/20/processing-kinect-v2-color-streams-in-parallel.aspxProcessing Kinect v2 Color Streams in Parallel I've really been enjoying being a part of the Kinect for Windows Developer's Preview. The new hardware has some really impressive capabilities. However, with great power comes great system specs. Unfortunately, my little laptop that could is not 100% up to the task; I've had to get a little creative. The most disappointing thing I've run into is that I can't always cleanly display the color camera stream in managed code. I managed to strip the code down to what I believe is the bear minimum: using( ColorFrame _ColorFrame = e.FrameReference.AcquireFrame() ) { if( null == _ColorFrame ) return; BitmapToDisplay.Lock(); _ColorFrame.CopyConvertedFrameDataToIntPtr( BitmapToDisplay.BackBuffer, Convert.ToUInt32( BitmapToDisplay.BackBufferStride * BitmapToDisplay.PixelHeight ), ColorImageFormat.Bgra ); BitmapToDisplay.AddDirtyRect( new Int32Rect( 0, 0, _ColorFrame.FrameDescription.Width, _ColorFrame.FrameDescription.Height ) ); BitmapToDisplay.Unlock(); } With this snippet, I'm placing the converted Bgra32 color stream directly on the BackBuffer of the WriteableBitmap. This gives me pretty smooth playback, but I still get the occasional freeze for half a second. After a bit of profiling, I discovered there were a few problems. The first problem is the size of the buffer along with the conversion on the buffer. At this time, the raw image format of the data from the Kinect is Yuy2. This is great for direct video processing. It would be ideal if I had a WriteableVideo object in WPF. However, this is not the case. Further digging led me to the real problem. It appears that the SDK is converting the input serially. Let's think about this for a second. The color camera is a 1080p camera. As we should all know, this give us a native resolution of 1920 x 1080. This produces 2,073,600 pixels. Yuy2 uses 4 bytes per 2 pixel, for a buffer size of 4,147,200 bytes. Bgra32 uses 4 bytes per pixel, for a buffer size of 8,294,400 bytes. The SDK appears to be doing this on one thread. I started wondering if I chould do this better myself. I mean, I have 8 cores in my system. Why can't I use them all? The first problem is converting a Yuy2 frame into a Bgra32 frame. It is NOT trivial. I spent a day of research of just how to do this. In the end, I didn't even produce the best algorithm possible, but it did work. After I managed to get that to work, I knew my next step was the get the conversion operation off the UI Thread. This was a simple process of throwing the work into a Task. Of course, this meant I had to marshal the final write to the WriteableBitmap back to the UI thread. Finally, I needed to vectorize the operation so I could run it safely in parallel. This was, mercifully, not quite as hard as I thought it would be. I had my loop return an index to a pair of pixels. From there, I had to tell the loop to do everything for this pair of pixels. If you're wondering why I did it for pairs of pixels, look back above at the specification for the Yuy2 format. I won't go into full detail on why each 4 bytes contains 2 pixels of information, but rest assured that there is a reason why the format is described in that way. The first working attempt at this algorithm successfully turned my poor laptop into a space heater. I very quickly brought and maintained all 8 cores up to about 97% usage. That's when I remembered that obscure option in the Task Parallel Library where you could limit the amount of parallelism used. After a little trial and error, I discovered 4 parallel tasks was enough for most cases. This yielded the follow code: private byte ClipToByte( int p_ValueToClip ) { return Convert.ToByte( ( p_ValueToClip < byte.MinValue ) ? byte.MinValue : ( ( p_ValueToClip > byte.MaxValue ) ? byte.MaxValue : p_ValueToClip ) ); } private void ColorFrameArrived( object sender, ColorFrameArrivedEventArgs e ) { if( null == e.FrameReference ) return; // If you do not dispose of the frame, you never get another one... using( ColorFrame _ColorFrame = e.FrameReference.AcquireFrame() ) { if( null == _ColorFrame ) return; byte[] _InputImage = new byte[_ColorFrame.FrameDescription.LengthInPixels * _ColorFrame.FrameDescription.BytesPerPixel]; byte[] _OutputImage = new byte[BitmapToDisplay.BackBufferStride * BitmapToDisplay.PixelHeight]; _ColorFrame.CopyRawFrameDataToArray( _InputImage ); Task.Factory.StartNew( () => { ParallelOptions _ParallelOptions = new ParallelOptions(); _ParallelOptions.MaxDegreeOfParallelism = 4; Parallel.For( 0, Sensor.ColorFrameSource.FrameDescription.LengthInPixels / 2, _ParallelOptions, ( _Index ) => { // See http://msdn.microsoft.com/en-us/library/windows/desktop/dd206750(v=vs.85).aspx int _Y0 = _InputImage[( _Index << 2 ) + 0] - 16; int _U = _InputImage[( _Index << 2 ) + 1] - 128; int _Y1 = _InputImage[( _Index << 2 ) + 2] - 16; int _V = _InputImage[( _Index << 2 ) + 3] - 128; byte _R = ClipToByte( ( 298 * _Y0 + 409 * _V + 128 ) >> 8 ); byte _G = ClipToByte( ( 298 * _Y0 - 100 * _U - 208 * _V + 128 ) >> 8 ); byte _B = ClipToByte( ( 298 * _Y0 + 516 * _U + 128 ) >> 8 ); _OutputImage[( _Index << 3 ) + 0] = _B; _OutputImage[( _Index << 3 ) + 1] = _G; _OutputImage[( _Index << 3 ) + 2] = _R; _OutputImage[( _Index << 3 ) + 3] = 0xFF; // A _R = ClipToByte( ( 298 * _Y1 + 409 * _V + 128 ) >> 8 ); _G = ClipToByte( ( 298 * _Y1 - 100 * _U - 208 * _V + 128 ) >> 8 ); _B = ClipToByte( ( 298 * _Y1 + 516 * _U + 128 ) >> 8 ); _OutputImage[( _Index << 3 ) + 4] = _B; _OutputImage[( _Index << 3 ) + 5] = _G; _OutputImage[( _Index << 3 ) + 6] = _R; _OutputImage[( _Index << 3 ) + 7] = 0xFF; } ); Application.Current.Dispatcher.Invoke( () => { BitmapToDisplay.WritePixels( new Int32Rect( 0, 0, Sensor.ColorFrameSource.FrameDescription.Width, Sensor.ColorFrameSource.FrameDescription.Height ), _OutputImage, BitmapToDisplay.BackBufferStride, 0 ); } ); } ); } } This seemed to yield a results I wanted, but there was still the occasional stutter. This lead to what I realized was the second problem. There is a race condition between the UI Thread and me locking the WriteableBitmap so I can write the next frame. Again, I'm writing approximately 8MB to the back buffer. Then, I started thinking I could cheat. The Kinect is running at 30 frames per second. The WPF UI Thread runs at 60 frames per second. This made me not feel bad about exploiting the Composition Thread. I moved the bulk of the code from the FrameArrived handler into CompositionTarget.Rendering. Once I was in there, I polled from a frame, and rendered it if it existed. Since, in theory, I'm only killing the Composition Thread every other hit, I decided I was ok with this for cases where silky smooth video performance REALLY mattered. This ode looked like this: private byte ClipToByte( int p_ValueToClip ) { return Convert.ToByte( ( p_ValueToClip < byte.MinValue ) ? byte.MinValue : ( ( p_ValueToClip > byte.MaxValue ) ? byte.MaxValue : p_ValueToClip ) ); } void CompositionTarget_Rendering( object sender, EventArgs e ) { using( ColorFrame _ColorFrame = FrameReader.AcquireLatestFrame() ) { if( null == _ColorFrame ) return; byte[] _InputImage = new byte[_ColorFrame.FrameDescription.LengthInPixels * _ColorFrame.FrameDescription.BytesPerPixel]; byte[] _OutputImage = new byte[BitmapToDisplay.BackBufferStride * BitmapToDisplay.PixelHeight]; _ColorFrame.CopyRawFrameDataToArray( _InputImage ); ParallelOptions _ParallelOptions = new ParallelOptions(); _ParallelOptions.MaxDegreeOfParallelism = 4; Parallel.For( 0, Sensor.ColorFrameSource.FrameDescription.LengthInPixels / 2, _ParallelOptions, ( _Index ) => { // See http://msdn.microsoft.com/en-us/library/windows/desktop/dd206750(v=vs.85).aspx int _Y0 = _InputImage[( _Index << 2 ) + 0] - 16; int _U = _InputImage[( _Index << 2 ) + 1] - 128; int _Y1 = _InputImage[( _Index << 2 ) + 2] - 16; int _V = _InputImage[( _Index << 2 ) + 3] - 128; byte _R = ClipToByte( ( 298 * _Y0 + 409 * _V + 128 ) >> 8 ); byte _G = ClipToByte( ( 298 * _Y0 - 100 * _U - 208 * _V + 128 ) >> 8 ); byte _B = ClipToByte( ( 298 * _Y0 + 516 * _U + 128 ) >> 8 ); _OutputImage[( _Index << 3 ) + 0] = _B; _OutputImage[( _Index << 3 ) + 1] = _G; _OutputImage[( _Index << 3 ) + 2] = _R; _OutputImage[( _Index << 3 ) + 3] = 0xFF; // A _R = ClipToByte( ( 298 * _Y1 + 409 * _V + 128 ) >> 8 ); _G = ClipToByte( ( 298 * _Y1 - 100 * _U - 208 * _V + 128 ) >> 8 ); _B = ClipToByte( ( 298 * _Y1 + 516 * _U + 128 ) >> 8 ); _OutputImage[( _Index << 3 ) + 4] = _B; _OutputImage[( _Index << 3 ) + 5] = _G; _OutputImage[( _Index << 3 ) + 6] = _R; _OutputImage[( _Index << 3 ) + 7] = 0xFF; } ); BitmapToDisplay.WritePixels( new Int32Rect( 0, 0, Sensor.ColorFrameSource.FrameDescription.Width, Sensor.ColorFrameSource.FrameDescription.Height ), _OutputImage, BitmapToDisplay.BackBufferStride, 0 ); } }

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Export Gridview/Listview to Excel with Color formatting

In this article, I explain how to export Gridview / Listview to excel with same color formatting using .net.

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Synth LaF JLabel DISABLED color

- by mmoris

Hi all, Using the Synth LaF, I am unable to set a JLabel's FOREGROUND color for the DISABLED state. has anybody succeeded in doing this? Here is my label's style definition in my LaF.xml file. <style id="whiteLabelStyle"> <opaque value="false"/> <font name="Bitstream Vera Sans" size="16" /> <state> <color type="FOREGROUND" value="WHITE"/> </state> <state value="DISABLED"> <color type="FOREGROUND" value="BLACK"/> </state> </style> <bind style="whiteLabelStyle" type="name" key="WhiteOrbitLabel"/> Please not that all the other styles defined in my LaF.xml file are rendered properly in my application including my label's WHITE normal state color (it just never goes to black when I do lbl.setEnabled(false) Also, going through the Synth code, I have found the following comment in SynthStyle.getColor if ((context.getComponentState() & SynthConstants.DISABLED) != 0) { //This component is disabled, so return the disabled color. //In some cases this means ignoring the color specified by the //developer on the component. In other cases it means using a //specified disabledTextColor, such as on JTextComponents. //For example, JLabel doesn't specify a disabled color that the //developer can set, yet it should have a disabled color to the //text when the label is disabled. This code allows for that. if (c instanceof JTextComponent) { JTextComponent txt = (JTextComponent)c; Color disabledColor = txt.getDisabledTextColor(); if (disabledColor == null || disabledColor instanceof UIResource) { return getColorForState(context, type); } } else if (c instanceof JLabel && (type == ColorType.FOREGROUND || type == ColorType.TEXT_FOREGROUND)){ return getColorForState(context, type); } But I could not figure out how to set a disabled color for a JLabel Thanks for your help!

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Numeric representation of a color

- by George Johnston

What would be the best format to numerically represent a color in .NET so that I wouldn't have to use the Color object? Right now I am saving the color as a the HTML representation, but in order to use it I have to parse it out. I am dealing with a 800x600 canvas that stores a color value for each pixel and I need to be able to render the color out as quick as possible without bloating my application out to storing 500k+ color objects.

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Using selector to change TextView text color

- by rafuru

I'm trying to use a TextView to define the style of a TabWidget on a tabhost. I just created a selector for bgcolor and works fine, but i want to make a selector for textColor but the text color don't change: This is my tab_text_selector.xml: <?xml version="1.0" encoding="utf-8"?> <selector xmlns:android="http://schemas.android.com/apk/res/android" > <item android:state_selected="true" android:color="@android:color/white" /> <item android:state_focused="true" android:color="@android:color/white" /> <item android:state_pressed="true" android:color="@android:color/white" /> </selector> And this is the code when i'm trying to use on a textView: TextView txtTab=new TextView(this); txtTab.setTextColor(R.drawable.tab_text_selector); txtTab.setBackgroundResource(R.drawable.tab_bg_selector); txtTab.setGravity(Gravity.CENTER); txtTab.setText("Agregar Idea"); I know the text color must be white in any case but it doesn't.

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solve TOR edge node problem by using .onion proxy?

- by rd.

I would like to improve the TOR network, where the exit nodes are a vulnerability to concealing traffic. From my understanding, traffic to .onion sites are not decrypted by exit nodes, so therefore - in theory - a .onion site web proxy could be used to further anonymize traffic. Yes/no? perhaps you have insight into the coding and routing behind these concepts to elaborate on why this is a good/not good idea.

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Silverlight dropdown and child page background color issue in Full Screen mode

Silverlight dropdown and child page background color issue in Full Screen mode.

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How to change color of the frame of a maximizing window

- by SteliosSk

Though I have read and tried some advises regarding the change of colors in a theme, I found no answer regarding my question, which is: When I drag a window to the left (or right or up) side of the screen an orange frame shows up, indicating the area that the window will occupy. This frame is in orange. Can you please inform me how can I change this color to blueish, to match my theme? At this point, I would like to inform you that Zorin OS has this blueish frame instead of orange, but I do not know where this color comes from.

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Color based collision detection

- by user1486826

I am making a game where you fly a ship around some randomly generated planets. Since I am using a for loop to draw over 5000 planets, using the rectangle class or an oval-type class for this is not an option, since creating many objects will severely affect performance. Bitmasking each planet will likely result in performance issues too, so the only candidate is color based collision detection, because I don't need to apply some sort of object to everything I want to check for collisions. Is any way to check the perimeter around the ship for a certain color?

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Emulating old-school sprite flickering (theory and concept)

- by Jeffrey Kern

I'm trying to develop an oldschool NES-style video game, with sprite flickering and graphical slowdown. I've been thinking of what type of logic I should use to enable such effects. I have to consider the following restrictions if I want to go old-school NES style: No more than 64 sprites on the screen at a time No more than 8 sprites per scanline, or for each line on the Y axis If there is too much action going on the screen, the system freezes the image for a frame to let the processor catch up with the action From what I've read up, if there were more than 64 sprites on the screen, the developer would only draw high-priority sprites while ignoring low-priority ones. They could also alternate, drawing each even numbered sprite on opposite frames from odd numbered ones. The scanline issue is interesting. From my testing, it is impossible to get good speed on the XBOX 360 XNA framework by drawing sprites pixel-by-pixel, like the NES did. This is why in old-school games, if there were too many sprites on a single line, some would appear if they were cut in half. For all purposes for this project, I'm making scanlines be 8 pixels tall, and grouping the sprites together per scanline by their Y positioning. So, dumbed down I need to come up with a solution that.... 64 sprites on screen at once 8 sprites per 'scanline' Can draw sprites based on priority Can alternate between sprites per frame Emulate slowdown Here is my current theory First and foremost, a fundamental idea I came up with is addressing sprite priority. Assuming values between 0-255 (0 being low), I can assign sprites priority levels, for instance: 0 to 63 being low 63 to 127 being medium 128 to 191 being high 192 to 255 being maximum Within my data files, I can assign each sprite to be a certain priority. When the parent object is created, the sprite would randomly get assigned a number between its designated range. I would then draw sprites in order from high to low, with the end goal of drawing every sprite. Now, when a sprite gets drawn in a frame, I would then randomly generate it a new priority value within its initial priority level. However, if a sprite doesn't get drawn in a frame, I could add 32 to its current priority. For example, if the system can only draw sprites down to a priority level of 135, a sprite with an initial priority of 45 could then be drawn after 3 frames of not being drawn (45+32+32+32=141) This would, in theory, allow sprites to alternate frames, allow priority levels, and limit sprites to 64 per screen. Now, the interesting question is how do I limit sprites to only 8 per scanline? I'm thinking that if I'm sorting the sprites high-priority to low-priority, iterate through the loop until I've hit 64 sprites drawn. However, I shouldn't just take the first 64 sprites in the list. Before drawing each sprite, I could check to see how many sprites were drawn in it's respective scanline via counter variables . For example: Y-values between 0 to 7 belong to Scanline 0, scanlineCount[0] = 0 Y-values between 8 to 15 belong to Scanline 1, scanlineCount[1] = 0 etc. I could reset the values per scanline for every frame drawn. While going down the sprite list, add 1 to the scanline's respective counter if a sprite gets drawn in that scanline. If it equals 8, don't draw that sprite and go to the sprite with the next lowest priority. SLOWDOWN The last thing I need to do is emulate slowdown. My initial idea was that if I'm drawing 64 sprites per frame and there's still more sprites that need to be drawn, I could pause the rendering by 16ms or so. However, in the NES games I've played, sometimes there's slowdown if there's not any sprite flickering going on whereas the game moves beautifully even if there is some sprite flickering. Perhaps give a value to each object that uses sprites on the screen (like the priority values above), and if the combined values of all objects w/ sprites surpass a threshold, introduce the sprite flickering? IN CONCLUSION... Does everything I wrote actually sound legitimate and could work, or is it a pipe dream? What improvements can you all possibly think with this game programming theory of mine?

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Photoshop CS4. How do I make sure my color stays the same in my different .psd files? (could be RGB

- by Kris

I asked 2 photoshop experts I know but they haven't got a clue because all my settings are exactly the same, in both files. (except the RGB type !! I'm not sure. Please read on) I use RGB color, 72DPI, 8 bits / channel. No adjustments (filters, like greyscale, etc ...) are selected / used. The layers are both normal, and opacity and fill are 100% (yes, in both files). I took two screenshots, and you can see the difference: http://www.flickr.com/photos/30465871@N05/4623864297/ http://www.flickr.com/photos/30465871@N05/4624469754/ Both colors are ff795d, but that doesn't matter, any color I use gives me the same problem: they both look different. Now, I know the CMYK settings (see screenshots) are different, but when the settings are the same the color changes. Why is this happening and how do I solve this problem? My guess is I'm working with different a type of RGB. It's sRGB IE61966 - 2.1 in the file I created (file info raw data) but I can't find that in the file that started with a screenshot. If that's the problem, how do I change / convert the RGB, once the file is already open? Thank you.

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ICMP Redirect Theory VS. Application

- by joeqwerty

I'm trying to watch ICMP redirects in a lab using Cisco Packet Tracer (version 5.3.2) and I'm not seeing them, which leads me to believe that either my lab configuration isn't correct or my understanding of ICMP redirects isn't correct or that Packet Tracer doesn't support/use ICMP redirects. Here's what I believe to be true regarding ICMP redirects: Routers send ICMP redirects when all of these conditions are met: The interface on which the packet comes into the router is the same interface on which the packet gets routed out. The subnet or network of the source IP address is on the same subnet or network of the next-hop IP address of the routed packet. The datagram is not source-routed. The router kernel is configured to send redirects. I have the lab set up in Cisco Packet Tracer as displayed in the image and would expect to see an ICMP redirect from Router1 when pinging from PC1 to PC3. I'm not seeing the ICMP redirect and it looks like Router1 is actually routing all of the packets via Router2. I have IP ICMP debugging enabled on Router1 (and Router2) and I'm not seeing any ICMP redirect activity in either console. I'm also not seeing a route to the PC3 network in the routing table on PC1, which I think confirms that the ICMP redirect is not occurring. I'm using only static routing on Routers 1 and 2. Is my understanding of ICMP redirects incorrect, or is there a problem with my lab configuration or does Packet Tracer not support/use ICMP redirects?

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Can't change text color in Microsoft Word 2010

- by Wesley

I have Microsoft Office 2010 32-bit running on Windows 7 32-bit. When text is highlighted and a color is selected from the mini-toolbar or the ribbon, the text does not change color. If I change the color for multiple words, and select a different color for each word, the toolbar and ribbon will reflect each of the different colors that I chose, however it is not displayed in the document. So it appears that Word is aware of the text color and not as if it is simply not applying the change. What may be causing this inability to view text colors and how might I fix it? My only troubleshooting attempt so far has been to perform a repair installation of Office. EDIT 1 I created a document, typed a word, selected it and changed the color. I then saved the document as HTML. The text did not change color. This is the HTML in the document: <html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"> <head> <meta http-equiv=Content-Type content="text/html; charset=windows-1252"> <meta name=ProgId content=Word.Document> <meta name=Generator content="Microsoft Word 14"> <meta name=Originator content="Microsoft Word 14"> <link rel=File-List href="Document_1_files/filelist.xml">  <link rel=themeData href="Document_1_files/themedata.thmx"> <link rel=colorSchemeMapping href="Document_1_files/colorschememapping.xml">  <style>  </style>  </head> <body lang=EN-US style='tab-interval:.5in'> <div class=WordSection1> <p class=MsoNormal><o:p> </o:p></p> <p class=MsoNormal><span class=GramE><span style='color:red'>blah</span></span><span style='color:red'><o:p></o:p></span></p> </div> </body> </html> EDIT 2 I recorded a macro and did the following: Typed a word Selected the word Changed the color. Oddly, I had some strange issues while the macro was recorded. I could not select text with my cursor. I had to select the text with control a and then apply the color change. I then couldn't deselect the selected text. Nonetheless, the text showed that it had a different color in the toolbar, but the color did not display in the document. Here's the macro: Sub Change_Text_Color() ' ' Change_Text_Color Macro ' ' Selection.TypeText Text:="Test Text" Selection.WholeStory Selection.WholeStory End Sub EDIT 3 I opened WordPad and created some text and was able to successfully change the color. If I copy and paste the colored text into a Word 2010 document, the color is lost. However, if you place the I-beam in the text and then look at the color selection drop-down menu on the ribbon or mini-toolbar, you can see that the proper color that the text should be in is highlighted. Edit 4 I uninstalled the entire Office 2010 Suite, rebooted and then reinstalled the suite. No change in behavior. Edit 5 Text cannot be colored in Excel either.

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