On Sat, 28 Jun 2025 20:06:29 GMT, Alexey Ivanov <aiva...@openjdk.org> wrote:
>> it might be possible we should use one for the left/top part and another for >> the right/bottom so we will not create a gaps. > >> Please double-check whether you need to use Region.clipScale() instead. > > @mrserb We use `Region.clipRound` for converting coordinates in > `SwingUtilities3.paintBorder`: > > https://github.com/openjdk/jdk/blob/a23de2ec090628b52532ee5d9bd4364a97499f5b/src/java.desktop/share/classes/com/sun/java/swing/SwingUtilities3.java#L231-L236 > > These formulas were introduced in #10681 > ([JDK-8282958](https://bugs.openjdk.org/browse/JDK-8282958)); and after > refactoring #11571 > ([JDK-8294680](https://bugs.openjdk.org/browse/JDK-8294680)), the new > formulas resolved [JDK-8294921](https://bugs.openjdk.org/browse/JDK-8294921) > after #7449 ([JDK-8279614](https://bugs.openjdk.org/browse/JDK-8279614)) > where there was a gap between the component edge and its border. These > formulas specifically addressed the situation with gaps and were developed > while we worked on making `LineBorder` and `EtchedBorder` render better at > fractional scales. > > So, using `clipRound` seems good enough. Initially, [I > suggested](https://bugs.openjdk.org/browse/JDK-8349188?focusedId=14758933&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14758933) > using `(int) (this.thickness * scaleFactor)`, but `clipRound` gives better > results. > >> I actually do not remember when to use one over the other. Maybe if you find >> a review request for the patch where these methods were added, you can >> confirm which one should be used. > > I couldn't find anything explaining where `clipScale` is better than > `clipRound`. The discussion for > [JDK-8000629](https://bugs.openjdk.org/browse/JDK-8000629) started in [March > 2013](https://mail.openjdk.org/pipermail/awt-dev/2013-March/004486.html) and > continued in [April > 2013](https://mail.openjdk.org/pipermail/awt-dev/2013-April/004577.html). > >> I checked the current source, and it seems that we randomly use one or the >> other, which seems incorrect. > > The javadoc for neither `clipScale` nor `clipRound` provides an example where > each method is best suitable. So, it's not that surprising either is used > randomly… > > It seems to me, that both > [`clipScale`](https://github.com/openjdk/jdk/blob/a23de2ec090628b52532ee5d9bd4364a97499f5b/src/java.desktop/share/classes/sun/java2d/pipe/Region.java#L159) > and > [`clipRound`](https://github.com/openjdk/jdk/blob/a23de2ec090628b52532ee5d9bd4364a97499f5b/src/java.desktop/share/classes/sun/java2d/pipe/Region.java#L140) > yield the same result. The former uses `Math.round`, whereas the latter uses > `Math.ceil` after subtracting `0.5`. > >> it might b... I am pretty sure these methods produce different results for negative coordinates. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/26025#discussion_r2173617318
