> Region has floor and ceiling functions that ensure that calling them twice in > a row will yield the same result: > > ceil(x) = ceil(ceil(x)) > > However, due to use of a constant `EPSILON` which is added/subtracted before > doing the rounding, this only works for small numbers (in the range of 0-50 > approximately). For larger values and scales, rounding errors can easily > occur. This is visible as artifacts on screen where controls are a pixel > wider than they should be. > > The use of the `EPSILON` constant is incorrect, as its value depends on the > magnitude of the value in question (as magnitude increases, the fractional > precision decreases). > > The Math class offers the function `ulp` that should be used here. It > represents the smallest possible change in value for a given double. > > Extending the existing test case `snappingASnappedValueGivesTheSameValueTest` > to use larger magnitude numbers exposes the problems.
John Hendrikx has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision: - Print seed if test fails - Merge branch 'master' into feature/ceil-fix - Fix Region ceil/floor function guarantees to be more accurate ------------- Changes: - all: https://git.openjdk.org/jfx/pull/1118/files - new: https://git.openjdk.org/jfx/pull/1118/files/ee87060c..65e1475a Webrevs: - full: https://webrevs.openjdk.org/?repo=jfx&pr=1118&range=01 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1118&range=00-01 Stats: 731 lines in 31 files changed: 186 ins; 469 del; 76 mod Patch: https://git.openjdk.org/jfx/pull/1118.diff Fetch: git fetch https://git.openjdk.org/jfx.git pull/1118/head:pull/1118 PR: https://git.openjdk.org/jfx/pull/1118
