lacuna / artifex Goto Github PK
View Code? Open in Web Editor NEWa library for constructing geometric data
License: MIT License
a library for constructing geometric data
License: MIT License
Would it be possible to add difference and intersection operations for open shapes (Path2) versus closes ones (Region2)?
Hi,
I'm working with intersections in OPENRNDR and I have the following design made out of 4 segments (two lines and two curves):
There should be 5 intersections detected but only 4 are found. The original program simplified to only use the two involved segments looks like this:
fun doTest() {
val l = Line2.line(Vec2(512.0, 96.0), Vec2(128.0, 384.0))
val c = Bezier2.curve(Vec2(128.0, 384.0), Vec2(320.0, 168.0), Vec2(512.0, 384.0)) as Bezier2.QuadraticBezier2?
println(l)
println(c)
val i = Intersections.lineQuadratic(l, c)
println(i.size)
i.forEach { println(it) }
}
This is the output of the program:
a=[x=512.0, y=96.0], b=[x=128.0, y=384.0]
p0=[x=128.0, y=384.0], p1=[x=320.0, y=168.0], p2=[x=512.0, y=384.0]
0
Zero intersections are found.
This is a visualization of those vertices using Inkscape. Even if the blue line should be a curve, I think it shows that there should be an intersection:
Any ideas why this happens?
While trying out the Artifex library I run into some clipping artefacts while finding difference and intersections of two circles. I think the problem is best explained by showing a video: https://www.youtube.com/watch?v=HfnP3vG0E-g
Code is a bit hard to share as I have linked Artifex code to a somewhat large codebase. Here is the integration code: openrndr/openrndr@61b4962#diff-6d99a3e2c6edca20aea91f05e5079391
I found some cases in which intersections between cubic curves are not detected.
As the algorithm is iterative it is harder for me to figure out at which point something goes wrong.
Here a test program that can be dropped into src/io/lacuna/artifex
:
package io.lacuna.artifex;
import io.lacuna.artifex.utils.Intersections;
public class TEST2 {
public static void main(String[] args) {
Vec2 s0 = new Vec2(435.3194971681168, 905.231313655894);
Vec2 a0 = new Vec2(436.60194226635423, 904.5228510213844);
Vec2 b0 = new Vec2(438.3935801257989, 904.1857845636355);
Vec2 e0 = new Vec2(440.3919343740061, 904.1270373708342);
Vec2 s1 = new Vec2(435.198246034818, 896.3191997888123);
Vec2 a1 = new Vec2(436.84762896823827, 898.9951604687135);
Vec2 b1 = new Vec2(438.2241643938649, 902.5923131816958);
Vec2 e1 = new Vec2(439.1164972433261, 906.1884150468093);
// SVG for debugging
System.out.println("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n" +
"<svg width=\"420mm\" height=\"297mm\" version=\"1.1\" viewBox=\"0 0 420 297\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:cc=\"http://creativecommons.org/ns#\" xmlns:dc=\"http://purl.org/dc/elements/1.1/\" xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\">\n" +
" <g fill=\"none\" stroke=\"#000\" stroke-width=\".01\">");
System.out.println("<path d=\"M " + s0.x + "," + s0.y +
" L " + a0.x + "," + a0.y +
" L " + b0.x + "," + b0.y +
" L " + e0.x + "," + e0.y + "\" />");
System.out.println("<path d=\"M " + s1.x + "," + s1.y +
" L " + a1.x + "," + a1.y +
" L " + b1.x + "," + b1.y +
" L " + e1.x + "," + e1.y + "\" />");
System.out.println(" </g>\n" + "</svg>\n");
Bezier2.CubicBezier2 curve0 = (Bezier2.CubicBezier2) Bezier2.curve(s0, a0, b0, e0);
Bezier2.CubicBezier2 curve1 = (Bezier2.CubicBezier2) Bezier2.curve(s1, a1, b1, e1);
test2(curve0, curve1);
}
private static void test2(Bezier2.CubicBezier2 curve0, Bezier2.CubicBezier2 curve1) {
System.out.println("\n# Intersections between");
System.out.println("curve 0: " + curve0);
System.out.println("curve 1: " + curve1);
Vec2[] intersections = Intersections.intersections(curve0, curve1);
System.out.println(intersections.length + " intersections");
for (Vec2 intersection : intersections) {
System.out.println(intersection);
}
}
}
The output of the program:
<?xml version="1.0" encoding="UTF-8"?>
<svg width="420mm" height="297mm" version="1.1" viewBox="0 0 420 297" xmlns="http://www.w3.org/2000/svg" xmlns:cc="http://creativecommons.org/ns#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
<g fill="none" stroke="#000" stroke-width=".01">
<path d="M 435.3194971681168,905.231313655894 L 436.60194226635423,904.5228510213844 L 438.3935801257989,904.1857845636355 L 440.3919343740061,904.1270373708342" />
<path d="M 435.198246034818,896.3191997888123 L 436.84762896823827,898.9951604687135 L 438.2241643938649,902.5923131816958 L 439.1164972433261,906.1884150468093" />
</g>
</svg>
# Intersections between
curve 0: p0=[x=435.3194971681168, y=905.231313655894], p1=[x=436.60194226635423, y=904.5228510213844], p2=[x=438.3935801257989, y=904.1857845636355], p3=[x=440.3919343740061, y=904.1270373708342]
curve 1: p0=[x=435.198246034818, y=896.3191997888123], p1=[x=436.84762896823827, y=898.9951604687135], p2=[x=438.2241643938649, y=902.5923131816958], p3=[x=439.1164972433261, y=906.1884150468093]
0 intersections
And the produced svg (bounding boxes, vertices and colors rendered by Inkscape)
A declarative, efficient, and flexible JavaScript library for building user interfaces.
๐ Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
An Open Source Machine Learning Framework for Everyone
The Web framework for perfectionists with deadlines.
A PHP framework for web artisans
Bring data to life with SVG, Canvas and HTML. ๐๐๐
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
Some thing interesting about web. New door for the world.
A server is a program made to process requests and deliver data to clients.
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
Some thing interesting about visualization, use data art
Some thing interesting about game, make everyone happy.
We are working to build community through open source technology. NB: members must have two-factor auth.
Open source projects and samples from Microsoft.
Google โค๏ธ Open Source for everyone.
Alibaba Open Source for everyone
Data-Driven Documents codes.
China tencent open source team.