This is nowhere near my cup of tea so handle with extreme prejudice and also far form solution just some start point hints… First of all we need to define some constraints/assumptions in order to make this to work. user selects 4 lines representing 2 perpendicular planes and these 2 QUADs have the same height … Read more
The original poster wanted to DETECT an intersection between a line segment and a polygon. There was no need to LOCATE the intersection, if there is one. If that’s how you meant it, you can do less work than Liang-Barsky or Cohen-Sutherland: Let the segment endpoints be p1=(x1 y1) and p2=(x2 y2). Let the rectangle’s … Read more
You can do this pretty simply using the EncodedImage.scaleImage32() method. You’ll need to provide it with the factors by which you want to scale the width and height (as a Fixed32). Here’s some sample code which determines the scale factor for the width and height by dividing the original image size by the desired size, … Read more
Opencv (image processing and computer vision library written in c) has implementation for hough transform (the simple hough transform find lines in an image, while the generalized one finds more complex objects) so that could be a good start. For the rectangles which do have closed corners there are also corner detectors such as cornerHarris … Read more
What you want is called planar rectification, and it’s not all that simple, I’m afraid. What you need to do is recover the homography that maps this oblique view of the van side onto the front-facing view. Photoshop / etc. have tools to do this for you given some control points; if you want to … Read more
Here is one method I found using R help: To create the individual image frames: jpeg(“/tmp/foo%02d.jpg”) for (i in 1:5) { my.plot(i) } dev.off() To make the movie, first install ImageMagick. Then call the following function (which calls “convert”, part of ImageMagick I suppose): make.mov <- function(){ unlink(“plot.mpg”) system(“convert -delay 0.5 plot*.jpg plot.mpg”) } Or … Read more
In both CSS and SVG filters, there is no conversion into HSV or HSL – the hueRotation shorthands are using a linear matrix approximation in RGB space to perform the hue rotation. This doesn’t conserve saturation or brightness very well for small rotations and highly saturated colors – as you’re seeing. A true hue rotation, … Read more
I’ve written some quick-and-dirty code that estimates this for Bézier curves of any degree. (Note: this is pseudo-brute force, not a closed-form solution.) Demo: http://phrogz.net/svg/closest-point-on-bezier.html /** Find the ~closest point on a Bézier curve to a point you supply. * out : A vector to modify to be the point on the curve * curve … Read more
The DOT user manual gives the following example of a graph with clusters with edges between clusters: IMPORTANT: The initial compound=true statement is required. digraph G { compound=true; subgraph cluster0 { a -> b; a -> c; b -> d; c -> d; } subgraph cluster1 { e -> g; e -> f; } b … Read more
Did you look at help(pdf) ? Usage: pdf(file = ifelse(onefile, “Rplots.pdf”, “Rplot%03d.pdf”), width, height, onefile, family, title, fonts, version, paper, encoding, bg, fg, pointsize, pagecentre, colormodel, useDingbats, useKerning) Arguments: file: a character string giving the name of the file. For use with ‘onefile=FALSE’ give a C integer format such as ‘”Rplot%03d.pdf”‘ (the default in that … Read more