> Proposed fix for [JDK-8260687][].
>
> It is noted the issue appeared after the [JDK-8257664][] (PR #1759) fix
> landed but the underlying problem is present even before that as demonstrated
> by using the following HTML document variant:
>
> <html>
> <body>
> <p style="font-size: 100%">16pt inherited from body</p>
> <p style="font-size: 16pt">16pt paragraph</p>
> </body>
> </html>
>
> with the program setup given in the ticket. The PR #1759 fix basically does
> just that – implies `font-size: 100%` where no `font-size` specified
> explicitly to ensure correctly computed font-size gets inherited when an
> ancestor specifies a percentage font-size different from `100%` (or `1em`) –
> otherwise the percentage is calculated and multiplied at every level of the
> inheritance, producing wrong results.
>
> ---
>
> The underlying problem is probably a combination of inconsistencies one may
> observe with the complex implementation of the
> [`W3C_LENGTH_UNITS`](https://docs.oracle.com/en/java/javase/15/docs/api/java.desktop/javax/swing/JEditorPane.html#W3C_LENGTH_UNITS)
> editor property. Starting with only the `HTMLDocument.styleSheet` gets its
> internal `StyleSheet.w3cLengthUnits` field set up according to the
> `JEditorPane.W3C_LENGTH_UNITS` property. Thus when a `font-size: 16pt` rule
> is part of the `HTMLEditorKit.styleSheet` which `w3cLengthUnits` generally
> remains `false` – querying the font for it from that style sheet yields a
> different result from querying the same rule via the
> `HTMLDocument.styleSheet`:
>
> JEditorPane editor = new JEditorPane();
> editor.putClientProperty(JEditorPane.W3C_LENGTH_UNITS, true);
>
> HTMLEditorKit htmlKit = new HTMLEditorKit();
> editor.setEditorKit(htmlKit);
>
> HTMLDocument htmlDoc = (HTMLDocument) editor.getDocument();
>
> StyleSheet kitStyles = htmlKit.getStyleSheet();
> StyleSheet docStyles = htmlDoc.getStyleSheet();
> assert Arrays.asList(docStyles.getStyleSheets()).contains(kitStyles);
>
> System.out.println(docStyles.getFont(docStyles.getRule("body"))); //
> [1]
>
> kitStyles.addRule("body { font-family: sans-serif; font-size: 16pt;
> }");
>
> System.out.println(kitStyles.getFont(kitStyles.getRule("body"))); //
> font.size = 16 (subjectively not expected)
> System.out.println(docStyles.getFont(docStyles.getRule("body"))); //
> font.size ≠ [1] ≠ 16 (expected)
>
> That's probably fine as one may programmatically create and add more style
> sheets to the `HTMLDocument.styleSheet`. These style sheets may further turn
> out shared with multiple documents/editors with different `W3C_LENGTH_UNITS`
> settings.
>
> The next issue with the `W3C_LENGTH_UNITS` implementation, this PR proposes a
> fix for, is related to the current implementation of
> `StyleSheet.ViewAttributeSet.getAttribute()`:
>
> https://github.com/openjdk/jdk/blob/70b5b3119b2ed032b021a080f34a4fa28d092fb5/src/java.desktop/share/classes/javax/swing/text/html/StyleSheet.java#L2810-L2818
>
> which in turn invokes `CSS.FontSize.toStyleConstants()`:
>
> https://github.com/openjdk/jdk/blob/48c932e1f1e5a79a28211f72dc9f10d8fd30b955/src/java.desktop/share/classes/javax/swing/text/html/CSS.java#L2195-L2199
>
> One may notice the latter loses the `StyleSheet` context necessary to
> properly resolve `w3cLengthUnits` from `CSS.FontSize.getValue()`:
>
> https://github.com/openjdk/jdk/blob/48c932e1f1e5a79a28211f72dc9f10d8fd30b955/src/java.desktop/share/classes/javax/swing/text/html/CSS.java#L2049-L2061
>
> This context is properly sent from `StyleSheet.getFont()`, for example:
>
> https://github.com/openjdk/jdk/blob/70b5b3119b2ed032b021a080f34a4fa28d092fb5/src/java.desktop/share/classes/javax/swing/text/html/StyleSheet.java#L913-L914
>
> ---
>
> I'll further add a test based on `BodyInheritedFontSize.java` already given
> to [JDK-8260687][] – I just want to enhance it with the:
>
> <p style="font-size: 100%">16pt inherited from body</p>
>
> testing the issue from a different angle as noted at the beginning of this PR
> description.
>
> [JDK-8257664]: https://bugs.openjdk.java.net/browse/JDK-8257664
> "HTMLEditorKit: Wrong CSS relative font sizes"
> [JDK-8260687]: https://bugs.openjdk.java.net/browse/JDK-8260687 "Inherited
> font size is smaller than expected when using StyleSheet to add styles"
Stanimir Stamenkov has updated the pull request incrementally with one
additional commit since the last revision:
8260687: Adjust TestWrongCSSFontSize
- Always save image capture to the current working directory on test
failure;
- Save successful image capture with '-capture' program argument;
- Always save image capture with ".png" extension;
- Use '-w3cUnits' program argument to control the test.w3cUnits flag.
-------------
Changes:
- all: https://git.openjdk.java.net/jdk/pull/2515/files
- new: https://git.openjdk.java.net/jdk/pull/2515/files/454a02fa..60d93744
Webrevs:
- full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2515&range=06
- incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2515&range=05-06
Stats: 22 lines in 1 file changed: 14 ins; 1 del; 7 mod
Patch: https://git.openjdk.java.net/jdk/pull/2515.diff
Fetch: git fetch https://git.openjdk.java.net/jdk pull/2515/head:pull/2515
PR: https://git.openjdk.java.net/jdk/pull/2515
