pixel

I was developing a application that changes color image to gray image. However, some how the picture comes out wrong. I dont know what is wrong with the code. maybe the parameter that i put in is wrong please help. UIImage *c = [UIImage imageNamed:@"downRed.png"]; CGImageRef cRef = CGImageRetain(c.CGImage); NSData* pixelData = (NSData*) CGDataProviderCopyData(CGImageGetDataProvider(cRef)); size_t w = CGImageGetWidth(cRef); size_t h = CGImageGetHeight(cRef); unsigned char* pixelBytes = (unsigned char *)[pixelData bytes]; unsigned char* greyPixelData = (unsigned char*) malloc(w*h); for (int y =

I have written my own software in C# for performing microscopy imaging. See this screenshot . The images that can be seen there are of the same sample but recorded through physically different detectors. It s crucial for my experiments that these images be exactly aligned. I thought the easiest would be to somehow blend/substract the two bitmaps but this doesn't give me good results. Therefore I am looking for a better way to do this. It might be useful to point out that the images exist as arrays of intensities in memory and are converted to bitmaps for on-screen painting to my self written

Because of specific needs, in my android layout, I have used "mm" to provide size. In TextView also, I have provided sizes in "mm". When I do textView.getTextSize() , the size returned is always in pixel values. I want to convert that pixel value in "mm". For example, if I have set font size as "2mm", then on any device, when I do getTextSize() , I would like to get "2mm". Should I use any specific method for that? I could find answers to convert "mm" to "pixel" but could not find anything about converting vice-versa. Nimish Choudhary we use TypedValue.java float px = TypedValue.applyDimension

So say I have an image that I want to "pixelate". I want this sharp image represented by a grid of, say, 100 x 100 squares. So if the original photo is 500 px X 500 px, each square is 5 px X 5 px. So each square would have a color corresponding to the 5 px X 5 px group of pixels it swaps in for... How do I figure out what this one color, which is best representative of the stuff it covers, is? Do I just take the R G and B numbers for each of the 25 pixels and average them? Or is there some obscure other way I should know about? What is conventionally used in "pixelation" functions, say like in

When working with BufferedImage using the setRGB and getRGB methods, I noticed two things: the setRGB and getRGB methods can be incredibly slow on some systems (as much as two orders of magnitude slower than modifiyng the int[] array). there are no guarantee that a getRGB following a setRGB will give back the same pixel you passed This last point is basically pretty clear from the JavaDoc of setRGB , which states: ...For images with an IndexColorModel, the index with the nearest color is chosen. Seen I can work directly in a BufferedImage's int[] pixels, which I can access to by doing, for