On Fri, 5 Nov 2021 10:05:41 GMT, Laurent Bourgès <lbour...@openjdk.org> wrote:
>> Jeremy has updated the pull request incrementally with one additional commit >> since the last revision: >> >> 8176501: Method Shape.getBounds2D() incorrectly includes Bezier control >> points in bounding box >> >> Addressing some of Laurent's code review recommendations/comments: >> >> 1. use the convention t for the parametric variable x(t),y(t) >> 2. solve the quadratic equation using QuadCurve2d.solveQuadratic() or like >> Helpers.quadraticRoots() >> 3. always use braces for x = (a < b) ? ... >> 4. always use double-precision constants in math or logical operations: (2 >> * x => 2.0 * x) and (coefficients[3] != 0) => (coefficients[3] != 0.0) >> >> (There are two additional recommendations not in this commit that I'll ask >> about shortly.) >> >> See https://github.com/openjdk/jdk/pull/6227#issuecomment-959757954 > > src/java.desktop/share/classes/java/awt/geom/Path2D.java line 2189: > >> 2187: double t = tExtrema[i]; >> 2188: if (t > 0 && t < 1) { >> 2189: double x = x_coeff[0] + t * (x_coeff[1] + t * >> (x_coeff[2] + t * x_coeff[3])); > > using 3rd order polynom is only useful for cubic curves, for quads 2nd order > is enough. > How to improve precision on (abcd) or (bcd) polynomial evaluation ? Ideally the compensated-horner scheme should be used to guarantee optimal precision (2x slower): paper: https://www-pequan.lip6.fr/~jmc/polycopies/Compensation-horner.pdf See julia code: https://discourse.julialang.org/t/more-accurate-evalpoly/45932/6 ------------- PR: https://git.openjdk.java.net/jdk/pull/6227
