On Wed, 17 Nov 2021 08:53:07 GMT, Jeremy <d...@openjdk.java.net> wrote:
>> 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 feedback: "I would prefer having accumulate > functions called twice (using offset)" > > https://github.com/openjdk/jdk/pull/6227#issuecomment-970040098 test/jdk/java/awt/geom/Path2D/GetBounds2DPrecisionTest.java line 254: > 252: res[roots++] = q.divide(a, RoundingMode.HALF_EVEN); > 253: if (!q.equals(BigDecimal.ZERO)) { > 254: res[roots++] = c.divide(q, RoundingMode.HALF_EVEN); This divide operation suffers missing decimals: Use BigDecomal.setScale(40) to ascertain precision. See https://github.com/bourgesl/marlin-math/blob/c9bbfbac4565e81e54ce79fc02c38fcaa2fe0e48/src/main/java/test/FindExtremaAccuracyTest.java#L667 See cubic test fixed: https://github.com/bourgesl/marlin-math/blob/main/results/findExtrema/jdk17-2021-11-19-dist-cubic.log ------------- PR: https://git.openjdk.java.net/jdk/pull/6227
