RFR: 8341670: [Text, TextFlow] Public API for Text Layout Info [v33]

[Kevin Rushforth]

On Tue, 10 Jun 2025 18:49:20 GMT, Andy Goryachev <angorya at openjdk.org> wrote:

>> Please refer to
>> 
>> https://github.com/andy-goryachev-oracle/Test/blob/main/doc/Text/LayoutInfo.md
>> 
>> The RichTextArea control ([JDK-8301121](https://bugs.openjdk.org/browse/JDK-8301121)), or any custom control that needs non-trivial navigation within complex or wrapped text needs a public API to get information about text layout.
>> 
>> This change fixes the missing functionality by adding a new public method to the `Text` and `TextFlow` classes.:
>> 
>> 
>>     /**
>>      * Obtains the snapshot of the current text layout information.
>>      * @return the layout information
>>      * @since 25
>>      */
>>     public final LayoutInfo getLayoutInfo()
>> 
>> 
>> The `LayoutInfo` provides a view into the text layout within `Text`/`TextFlow` nodes such as:
>> 
>> - caret information
>> - text lines: offsets and bounds
>> - overall layout bounds
>> - text selection geometry
>> - strike-through geometry
>> - underline geometry
>> 
>> 
>> 
>> 
>> ## WARNINGS
>> 
>> Presently, information obtained via certain Text/TextField methods is incorrect with non-zero padding and borders, see [JDK-8341438](https://bugs.openjdk.org/browse/JDK-8341438).
>> 
>> This PR provides correct answers in the new API, leaving the behavior of the existing methods unchanged (there is a compatibility risk associated with trying to fix [JDK-8341438](https://bugs.openjdk.org/browse/JDK-8341438) ).
>> 
>> Also, the RTL support is out of scope for this PR, due to multiple pre-existing conditions, see https://bugs.openjdk.org/browse/JDK-8343557
>> 
>> 
>> ## Testing
>> 
>> The new APIs can be visually tested using the Monkey Tester on this branch:
>> https://github.com/andy-goryachev-oracle/MonkeyTest/tree/text.layout.api
>> 
>> in the Text and TextFlow pages:
>> ![Screenshot 2024-11-04 at 11 38 21](https://github.com/user-attachments/assets/2e17e55c-f819-4742-8a42-b9af2b6bac72)
>> 
>> Two very basic headful tests have been added.
>> 
>> 
>> ## See Also
>> 
>> https://github.com/FXMisc/RichTextFX/pull/1246
>
> Andy Goryachev has updated the pull request incrementally with one additional commit since the last revision:
> 
>   text origin

The fix looks good. The tests look good, although I noted a few "assertEquals" in the test with expected and actual parameters reserved (meaning the error message would be confusing if they ever failed).

tests/system/src/test/java/test/robot/javafx/scene/TextFlow_TextLayout_Test.java line 81:

> 79: 
> 80:         // caret is one line
> 81:         assertEquals(ci.getSegmentCount(), 1);

Expected and actual are reversed, here and a few others below (most are OK).

tests/system/src/test/java/test/robot/javafx/scene/TextFlow_TextLayout_Test.java line 136:

> 134:         assertEquals(la.getTextLineCount(), 3);
> 135:         List<TextLineInfo> ls = la.getTextLines(false);
> 136:         assertNotNull(ls);

Minor: maybe check the following, too?


        assertEquals(3, ls.size());

tests/system/src/test/java/test/robot/javafx/scene/Text_TextLayout_Test.java line 83:

> 81: 
> 82:         // caret is one line
> 83:         assertEquals(ci.getSegmentCount(), 1);

Expected and actual are reversed, here and a few others below (most are OK).

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

PR Review: https://git.openjdk.org/jfx/pull/1596#pullrequestreview-2918282270
PR Review Comment: https://git.openjdk.org/jfx/pull/1596#discussion_r2140820285
PR Review Comment: https://git.openjdk.org/jfx/pull/1596#discussion_r2140823296
PR Review Comment: https://git.openjdk.org/jfx/pull/1596#discussion_r2140830505