2014/10/15 下午 10:09:09

iphone Programming Glossary: floats

http://stackoverflow.com/questions/10049533/correcting-floating-point-numbers

are stored and why we have this problem in the first place see this wikipedia article IEEE 754 1985 . Basically floats are stored as a binary representation of the value and only have so many bits to use so they quickly run out and have to..

What's the difference between NSNumber and NSInteger?

http://stackoverflow.com/questions/1285098/whats-the-difference-between-nsnumber-and-nsinteger

between NSNumber and NSInteger Are there more primitives like these that I should know about use Is there one for floats iphone objective c nsnumber primitive types nsinteger share improve this question The existing answers are useful adding.. seconds without having to deal with a struct. When you move into the graphics world where Core Graphics lives suddenly floats are all around you hovering in the air haha . So it makes sense to introduce a CGFloat there. This paragraph is all educated..

iPhone writing binary data

http://stackoverflow.com/questions/1526416/iphone-writing-binary-data

writing binary data How do you write binary data to a file I want to write floats to a file raw and then read them back as floats. How do you do that iphone binary share improve this question Been.. binary data How do you write binary data to a file I want to write floats to a file raw and then read them back as floats. How do you do that iphone binary share improve this question Been experimenting with this NSArray paths NSSearchPathForDirectoriesInDomains..

Strange problem comparing floats in objective-C

http://stackoverflow.com/questions/1614533/strange-problem-comparing-floats-in-objective-c

problem comparing floats in objective C At some point in an algorithm I need to compare the float value of a property of a class to a float. So.. numbers without a modifier are considered to be double in C. However in C there is no exact representation of 0.1 in floats and doubles. Now using a float gives you a small error. Using a double gives you an even smaller error. The problem now..

OpenGL ES iPhone - drawing anti aliased lines

http://stackoverflow.com/questions/1813035/opengl-es-iphone-drawing-anti-aliased-lines

in opacity. glColorPointer 4 GL_UNSIGNED_BYTE 0 colors glEnableClientState GL_COLOR_ARRAY points is a pointer to floats 2 per vertex glVertexPointer 2 GL_FLOAT 0 points glEnableClientState GL_VERTEX_ARRAY glDrawArrays GL_TRIANGLE_STRIP 0 points_count..

Using the apple FFT and accelerate Framework

http://stackoverflow.com/questions/3398753/using-the-apple-fft-and-accelerate-framework

is vDSP_fft_zrip setupReal A stride log2n FFT_FORWARD vDSP_fft_zrip setupReal A stride log2n FFT_INVERSE FFT on n real floats and then reverse to get back to where we started. ip stands for in place which means A gets overwritten That's the reason.. on microphone input and we have set it up so that some callback gets triggered every time the microphone gets in 1024 floats. Supposing the microphone sampling rate was 44.1kHz so that's ~44 frames sec. So our time window is whatever the time duration.. sec. So our time window is whatever the time duration of 1024 samples is ie 1 44 s. So we would pack A with 1024 floats from the mic set log2n 10 2^10 1024 precalculate some bobbins setupReal and vDSP_fft_zrip setupReal A stride log2n FFT_FORWARD..

Creating UIImage from raw RGBA data

http://stackoverflow.com/questions/4545237/creating-uiimage-from-raw-rgba-data

It turns out the problem is a pretty silly mistake that both of us overlooked. UIImage dimensions are stored as floats not integers. D Try NSLog @ resultImg width f height f newImage.size.width newImage.size.height Instead. The image size..

Convert decimal to fraction in Objective-C?

http://stackoverflow.com/questions/5552537/convert-decimal-to-fraction-in-objective-c

said you'll find all necessary information along with C code in the answers of this other question How to convert floats to human readable fractions Specifically this answer featuring actual C code . Here is a quick c function wrapper of said..

How to display a progress indicator overlay/HUD on iPhone?

http://stackoverflow.com/questions/593147/how-to-display-a-progress-indicator-overlay-hud-on-iphone

a progress indicator overlay HUD on iPhone I want to display a progress indicator in a semi transparent box that floats over a table view. In other words when the table contents are being downloaded I want an Updating label to appear over it...

iOS Stream Audio from one iOS Device to Another

http://stackoverflow.com/questions/8357514/ios-stream-audio-from-one-ios-device-to-another

data you receive matches exactly. Checkout things like number of channels mono or stereo number of frames integers or floats and sample rate. If anything doesn't match up you'll either get EXC_BAD_ACCESS errors as you work your way through the respective.. an integer or a float. Mono or stereo you have one or two channels in a frame. That defines how many integers or floats are in that frame. Then you have frames per packet probably 1 . Your sample rate determines how many of those packets you..