The trick is to use a combination of the Polygon class methods: from shapely.geometry import Polygon # Create polygon from lists of points x = [0.0, 0.0, 1.0, 1.0, 0.0] y = [0.0, 1.0, 1.0, 0.0, 0.0] poly = Polygon(zip(x,y)) # Extract the point values that define the perimeter of the polygon xx, yy = … Read more
I thought I might briefly mention my own polygon clipping and offsetting library – Clipper. While Clipper is primarily designed for polygon clipping operations, it does polygon offsetting too. The library is open source freeware written in Delphi, C++ and C#. It has a very unencumbered Boost license allowing it to be used in both … Read more
Some of the suggested methods will fail in the case of a non-convex polygon, such as a crescent. Here’s a simple one that will work with non-convex polygons (it’ll even work with a self-intersecting polygon like a figure-eight, telling you whether it’s mostly clockwise). Sum over the edges, (x2 − x1)(y2 + y1). If the … Read more
For graphics, I’d rather not prefer integers. Many systems use integers for UI painting (pixels are ints after all), but macOS, for example, uses float for everything. macOS only knows points and a point can translate to one pixel, but depending on monitor resolution, it might translate to something else. On retina screens half a … Read more
CSS Triangles: A Tragedy in Five Acts As alex said, borders of equal width butt up against each other at 45 degree angles: When you have no top border, it looks like this: Then you give it a width of 0… …and a height of 0… …and finally, you make the two side borders transparent: … Read more