2014/10/15 下午 10:05:12

iphone Programming Glossary: coefficients

Find the tangent of a point on a cubic bezier curve (on an iPhone)

http://stackoverflow.com/questions/4089443/find-the-tangent-of-a-point-on-a-cubic-bezier-curve-on-an-iphone

CGFloat t CGFloat a CGFloat b CGFloat c CGFloat d see also below for another way to do this that follows the 'coefficients' idea and is a little clearer CGFloat t2 t t CGFloat t3 t2 t return a a 3 t 3 a a t t 3 b t 6 b b 3 t t c 3 c 3 t t2 d t3.. t3 CGFloat bezierTangent CGFloat t CGFloat a CGFloat b CGFloat c CGFloat d note that abcd are aka x0 x1 x2 x3 the four coefficients .. A x3 3 x2 3 x1 x0 B 3 x2 6 x1 3 x0 C 3 x1 3 x0 D x0 and then... Vx 3At2 2Bt C first calcuate what are usually know as.. 3.0 b 3.0 a CGFloat C4 a not needed for this calculation finally it is easy to calculate the slope element using those coefficients return 3.0 C1 t t 2.0 C2 t C3 note that this routine works for both the x and y side simply run this routine twice once..

How do I detect a touch on a UIBezierPath and move a ball along that?

http://stackoverflow.com/questions/4854035/how-do-i-detect-a-touch-on-a-uibezierpath-and-move-a-ball-along-that

b 3.0 a CGFloat C4 a return 3.0 C1 t t 2.0 C2 t C3 The four precalculated values C1 C2 C3 C4 are sometimes called the coefficients of the bezier. Recall that a b c d are usually called the four control points. Of course t runs from 0 to 1 perhaps for..

Generating DSP filter coefficients in C/Java for time-domain convolution

http://stackoverflow.com/questions/8014018/generating-dsp-filter-coefficients-in-c-java-for-time-domain-convolution

DSP filter coefficients in C Java for time domain convolution I am writing a smartphone Android iPhone application that does some DSP. I am an.. to my time domain signal. From my understanding I need to perform convolution of my time domain samples and filter coefficients. In Matlab I would use the fir1 function to get the filter coefficients and the conv filter functions to apply the convolution... of my time domain samples and filter coefficients. In Matlab I would use the fir1 function to get the filter coefficients and the conv filter functions to apply the convolution. I know how to write the convolution function in Java C but I don't..

Transforming a rectangle image into a quadrilateral using a CATransform3D

http://stackoverflow.com/questions/9470493/transforming-a-rectangle-image-into-a-quadrilateral-using-a-catransform3d

points and build 16 equations out of A' A x u but it did not work I'm not sure of what I should use as z z' w and w' coefficients p The following picture shows what I want to do Here are some examples of points 276.523 236.438 517.656 208.945 275.984..