transformation

问题 What is the way to implement custom transformation (+ animation) on a view surface (similar to the images attached) ( not just the view bounds ). The question is mainly in what is the general way to do that (not exactly the 'water drop effect', but any examples would be appreciated for sure). I guess, that's some 'algorythmic' transformation of the layer layout 'grid', but not sure which way to 'dig' that in. (Another thought is that might be achieved with using some frameworks, however, I

问题 I need to shear and skew some images using python. I've come across this skimage module but I don't seem able to understand exactly how I'm supposed to use this. I've tried a few things, which obviously gave me errors, because as I suddenly realized later, I'm not passing in my image to the function. I then noticed that the function doesn't take my image as an input parameter in the first place. So how should the transformation be applied? Or is this even the right function to be looking at

问题 I want to use Sankey chart but with circle's instead of rectangles. I am following the example from Mike Bostock. I changed the code there to use circle by setting radius, but how to place the lines connecting nodes around circle. Any clue. Thanks. 回答1: first of all, I would like to tell you that I liked your idea. I will walk you through several simple steps needed to get a decent Sankey diagram with circles. The final result may not be ideal for your application, but I guess it may be

问题 Hoping there's a simple answer here but I can't find it anywhere. I have a numeric matrix with labelled rows and columns: 1 2 3 4 a 6 7 8 9 b 8 7 5 7 c 8 5 4 1 d 1 6 3 2 I would like a data.table (or a data.frame I can then convert) of the form: col row value 1 a 6 1 b 8 1 c 8 1 d 1 2 a 7 2 b 7 2 c 5 2 d 6 ... Any tips appreciated. 回答1: Use melt from reshape2: library(reshape2) #Fake data x <- matrix(1:12, ncol = 3) colnames(x) <- letters[1:3] rownames(x) <- 1:4 x.m <- melt(x) x.m Var1 Var2

问题 I am currently working on ray-tracing techniques and I think I've made a pretty good job; but, I haven't covered camera yet. Until now, I used a plane fragment for view plane which is located between (-width/2, height/2, 200) and (width/2, -height/2, 200) [200 is just a fixed number of z, can be changed]. Addition to that, I use the camera mostly on e(0, 0, 1000) , and I use a perspective projection. I send rays from point e to pixels, and print it to image's corresponding pixel after

问题 Normally the definition of a projection matrix P is the 3x4 matrix which projects point from world coordinates to image/pixel coordinates. The projection matrix can be split up into: K : a 3x4 camera matrix K with the intrinsic parameters T : a 4x4 transformation matrix with the extrinsic parameters The projection matrix is then P = K * T . What are the clear definitions of the following input to OpenCV's stereoRectify: cameraMatrix1 – First camera matrix (I assume it is the instrinsic K part

问题 have a little problem here: int IntegerTransformer::transformFrom(std::string string){ stream->clear(); std::cout<<string<<std::endl;; (*stream)<<string; int i; (*stream)>>i; std::cout<<i<<std::endl; return i; } I by calling this function with the string "67" (other values dont work too) i get this output: 67 6767 回答1: Did you notice there are two std::cout in the function itself? Beside that also add this: stream->str(""); //This ensures that the stream is empty before you use it. (*stream)<

问题 have a little problem here: int IntegerTransformer::transformFrom(std::string string){ stream->clear(); std::cout<<string<<std::endl;; (*stream)<<string; int i; (*stream)>>i; std::cout<<i<<std::endl; return i; } I by calling this function with the string "67" (other values dont work too) i get this output: 67 6767 回答1: Did you notice there are two std::cout in the function itself? Beside that also add this: stream->str(""); //This ensures that the stream is empty before you use it. (*stream)<

问题 how do we extract scale matrix from model view matrix? Right now I am taking length of each coloumn, but it fails when the scale is negative. here is my code: float xs = matrix[0][0] * matrix[0][1] * matrix[0][2] * matrix[0][3] < 0 ? -1 : 1; float ys = matrix[1][0] * matrix[1][1] * matrix[1][2] * matrix[1][3] < 0 ? -1 : 1; float zs = matrix[2][0] * matrix[2][1] * matrix[2][2] * matrix[2][3] < 0 ? -1 : 1; glm::vec3 new_scale; new_scale.x = xs* glm::sqrt( matrix[0][0] * matrix[0][0] + matrix[0]

问题 I have written an application which uses a pipeline of 15 XSL stylesheets, and I'm beginning to work on tuning its performance. It's designed to be portable, so that it can be run in both the web browser environment, and on the desktop. On the desktop, I think it may make sense to keep the stylesheets separated out as a pipeline of multiple transformations, as this allows each individual transformation to be run in its own thread, which can be very efficient on CPUs with multiple cores.