polygon

I have 1 red polygon say and 50 randomly placed blue polygons - they are situated in geographical 2D space . What is the quickest/speediest algorithim to find the the shortest distance between a red polygon and its nearest blue polygon? Bear in mind that it is not a simple case of taking the points that make up the vertices of the polygon as values to test for distance as they may not necessarily be the closest points. So in the end - the answer should give back the closest blue polygon to the singular red one. This is harder than it sounds! I doubt there is better solution than calculating

The program I am writing draws multiple stars on the screen and gives them random directions and speeds. The stars will bounce off the edges of the panel and stay inside. I need to have the stars rotating as they are moving. I have tried so many things and I cannot figure it out. Below is the code I use to draw the stars and move them. Additional Information: -the stars are in a collection called "stars" -there are two classes that I wrote, "Star" and "MyJPanel" Set the points: (in Star class) for (double current = 0; current < nPoints; current += 1) { i = (int)current; int[] X = new int

i have made a transform and rendered a Polygon object with it(mesh is of type Polygon): at.setToTranslation(gameObject.position.x, gameObject.position.y); at.rotate(Math.toRadians(rotation)); at.scale(scale, scale); g2d.setTransform(at); g2d.fillPolygon(mesh); now i want to return the exact mesh i rendered so that i can do collision checks on it. only problem is that if i return mesh it returns the un-transformed mesh. so i tried setting the transform to the Polygon object (mesh) like so: mesh = (Polygon)at.createTransformedShape(mesh); but unfortunately at.createTransformedShape() returns a

I have a set of points. This set of points do define a (non convex) polygon but its not ordered. Since it's not ordered I cannot just draw from point to point to draw its border. How can I sort it in a way I can walk through this point list and draw a polygon? My first idea was to use a convex hull but my polygons are, most of the time, concave. I don't think there's a well-defined solution to this. Consider five points like this: . . . . . What polygon would be correct here? You have to order the points so you walk around the polygon with the interior on your left (or right) as you move from

Based on a grayscale image and an ordered closed polygon (may be concave), I want to get all grayscale values that lie inside a region of interest polygon (as likewise described in SciPy Create 2D Polygon Mask ). What is the most performant realisation of that in Qt 4.8? Endpoint should be some kind of QList<double> . Thanks for your advices. In addition, is it possible to compute a floating point mask (e.g. 0 for outside the polygon, 0.3 for 30% of the pixel area is within the polygon, 1 for completely inside the polygon)? However, that's just an extra, endpoint would be QPair<double, double>