ellipse

问题 Dear fellow stackoverflow users, I face a problem as follows: I would like to fit a 3D ellipsoid to 3D data points within my python script. The starting data are a set of x, y and z coordinates (cartesian coordinates). What I would like to get are a and c in the defining equation of the best-fit ellipsoid of the convex hull of the 3D data points. The equation is, in the properly rotated and translated coordinate system: So the tasks I would ideally like to do are: Find convex hull of 3D data

问题 I'm writing a basic 2D shape library in Python (primarily for manipulating SVG drawings), and I'm at a loss for how to efficiently calculate the intersection points of two ellipses. Each ellipse is defined by the following variables (all floats): c: center point (x, y) hradius: "horizontal" radius vradius: "vertical" radius phi: rotation from coordinate system's x-axis to ellipse's horizontal axis Ignoring when the ellipses are identical, there could be 0 through 4 intersection points (no

问题 I'm writing a basic 2D shape library in Python (primarily for manipulating SVG drawings), and I'm at a loss for how to efficiently calculate the intersection points of two ellipses. Each ellipse is defined by the following variables (all floats): c: center point (x, y) hradius: "horizontal" radius vradius: "vertical" radius phi: rotation from coordinate system's x-axis to ellipse's horizontal axis Ignoring when the ellipses are identical, there could be 0 through 4 intersection points (no

问题 This question already has answers here : Applying an ellipsis to multiline text [duplicate] (25 answers) Closed last month . I would like to add an ellipse (...) to the end of text that overflows past 2 lines. Currently I have tried the whitespace nowrap but that does it for only one line. How can I achieve a 2 line ellipse (...)? .details { display: inline-flex; /* text-align: center; */ /* display:block; */ /* display:table-cell; vertical-align:middle; */ /* background-color: grey; */

问题 this is the code I use to create and draw an ellipsoid with OpenGL with shader const float _2pi = 2.0f * M_PI; std::vector<glm::vec3> positions; std::vector<glm::vec3> normals; std::vector<glm::vec2> textureCoords; for(int i = 0; i <= stacks; ++i) { // V texture coordinate float V = i / (float)stacks; float phi = V * M_PI; for( int j = 0; j <= slices; ++j) { // U texture coordinate float U = j / (float)slices; float theta = U * _2pi; float X = a * cos(theta) * cos(phi); float Y = b * cos

问题 The title pretty much says it all. I'm looking for a convenient way to generate a geoJSON polygon defining an ellipse similar to d3-geo's d3.geoCircle()(); I want to use this GeoJSON ellipse with d3-geo. To clarify with and example, Cesium has this capability with a simple function allowing you to create an ellipse like so: var ellipse = new Cesium.EllipseGeometry({ center : Cesium.Cartesian3.fromDegrees(-75.59777, 40.03883), semiMajorAxis : 500000.0, semiMinorAxis : 300000.0, rotation :

问题 I'm trying to make a function in Lua or VB based code to draw / plot an ellipse and also a filled ellipse. I don't have much knowledge about this math and I can use some help. I googled everything there is to google about drawing ellipses with code but I can't find a good simple working example that i can code into my Lua / VB code. here are a few websites i visited but couldn't make the code work or couldn't convert the code to Lua or VB properly... https://sites.google.com/site/ruslancray

问题 I am currently trying to animate a series of images where for each image an initially unknown number of ellipses are drawn. I have tried many things so far, but haven't found a solution yet, though I guess I came close. Here is my code: import matplotlib.pyplot as plt from matplotlib.patches import Ellipse def plot_images(img1, img2, objects, ax): im1 = ax.imshow(img1) im2 = ax.imshow(img2 with transparency as an overlay) # plotting an ellipse for each object e = [None]*len(objects) for j in

问题 I need to draw a ring, with given thickness, that looks something like this: The center must be transparent, so that it doesn't cover previously drawn shapes. (or other rings) I've tried something like this: //g is a Graphics2D object g.setColor(Color.RED); g.drawOval(x,y,width,height); g.setColor(Color.WHITE); g.drawOval(x+thickness,y+thickness,width-2*thickness,height-2*thickness); which draws a satisfactory ring, but it covers other shapes; the interior is white, not transparent. How can I

问题 I have a rectangle in .NET in which I draw an ellipse. I know the width, height and center point of that rectangle. Of course the center point of the rectangle is also the center point of the ellipse. I know how to calculate a point on a circle, however I have no clue about an ellipse. I have those parameters and an angle, i need the point on the ellipse, can someone post the formula? I saw somewhere you need to calculate 2 points in which 2 radii will go, the sum of the radii will be fixed