> This removes code that relied on consulting the Bezier control points to > calculate the Rectangle2D bounding box. Instead it's pretty straight-forward > to convert the Bezier control points into the x & y parametric equations. At > their most complex these equations are cubic polynomials, so calculating > their extrema is just a matter of applying the quadratic formula to calculate > their extrema. (Or in path segments that are quadratic/linear/constant: we do > even less work.) > > The bug writeup indicated they wanted Path2D#getBounds2D() to be more > accurate/concise. They didn't explicitly say they wanted CubicCurve2D and > QuadCurve2D to become more accurate too. But a preexisting unit test failed > when Path2D#getBounds2D() was updated and those other classes weren't. At > this point I considered either: > A. Updating CubicCurve2D and QuadCurve2D to use the new more accurate > getBounds2D() or > B. Updating the unit test to forgive the discrepancy. > > I chose A. Which might technically be seen as scope creep, but it feels like > a more holistic/better approach. > > Other shapes in java.awt.geom should not require updating, because they > already identify concise bounds. > > This also includes a new unit test (in Path2D/UnitTest.java) that fails > without the changes in this commit.
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 code review recommendation to calculate polynomial coefficients using differences / vector notation. https://github.com/openjdk/jdk/pull/6227#discussion_r743534560 I generally understand the intention of this change, but I don't know exactly how to test/evaluate it. The unit tests still pass. I ran some sample calculations involving a 100x100 Ellipse2D as it was rotated, and the two getBounds2D(..) implementations (before and after this commit) only differed by a few ulps (usually around 10^-15), as expected. ------------- Changes: - all: https://git.openjdk.java.net/jdk/pull/6227/files - new: https://git.openjdk.java.net/jdk/pull/6227/files/e617c722..b7ca69c8 Webrevs: - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6227&range=04 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6227&range=03-04 Stats: 19 lines in 1 file changed: 10 ins; 0 del; 9 mod Patch: https://git.openjdk.java.net/jdk/pull/6227.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/6227/head:pull/6227 PR: https://git.openjdk.java.net/jdk/pull/6227
