RFR: 8349188: LineBorder does not scale correctly

[Alexey Ivanov]

On Fri, 27 Jun 2025 18:11:46 GMT, Rajat Mahajan <rmahajan at openjdk.org> wrote:

> Modified the code to account for border thickness correctly and updated the related tests to make sure we are testing the new change.
> 
> Testing done.

Looks good except for a few nits.

src/java.desktop/share/classes/javax/swing/border/LineBorder.java line 166:

> 164:             Shape inner;
> 165: 
> 166:             int offs = clipRound(this.thickness*scaleFactor);

Suggestion:

            int offs = clipRound(this.thickness * scaleFactor);

src/java.desktop/share/classes/javax/swing/border/LineBorder.java line 167:

> 165: 
> 166:             int offs = clipRound(this.thickness*scaleFactor);
> 167: 

I'd leave out the added blank line, both `offs` and `size` are still tightly coupled, only the formula for `offs` is amended.

test/jdk/javax/swing/border/LineBorder/ScaledLineBorderTest.java line 117:

> 115: 
> 116:                 for (Point p : test.panelLocations) {
> 117:                     int y = (int) (p.y * test.scale) + (int) (SIZE.height * test.scale / 2);

This expression can be simplified:
Suggestion:

                    int y = (int) ((p.y + (SIZE.height / 2)) * test.scale);

This way may look clearer: find the vertical centre of the panel, taking into account the scale applied.

test/jdk/javax/swing/border/LineBorder/ScaledLineBorderTest.java line 302:

> 300:     private static String getImageFileName(final double scaling,
> 301:                                            int thickness) {
> 302:         return String.format("test%02d@%.2f.png", thickness, scaling);

Suggestion:

    private static String getImageFileName(final double scaling,
                                           final int thickness) {
        return String.format("test%02d@%.2f.png", thickness, scaling);

Declare both parameters as `final` to be consistent.

-------------

Changes requested by aivanov (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/26025#pullrequestreview-2967643714
PR Review Comment: https://git.openjdk.org/jdk/pull/26025#discussion_r2172687248
PR Review Comment: https://git.openjdk.org/jdk/pull/26025#discussion_r2172705614
PR Review Comment: https://git.openjdk.org/jdk/pull/26025#discussion_r2172695201
PR Review Comment: https://git.openjdk.org/jdk/pull/26025#discussion_r2172700022