RFR: 8341670: [Text, TextFlow] Public API for Text Layout Info [v18]

[Michael Strauß]

On Wed, 5 Mar 2025 21:18:39 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
>> 
>> 
>> This PR also adds the missing `strikeThroughShape()` method to complement the existing `underlineShape()` and `rangeShape()` for consistency sake:
>> 
>> 
>>     /**
>>      * Returns the shape for the strike-through in local coordinates.
>>      *
>>      * @param start the beginning character index for the range
>>      * @param end the end character index (non-inclusive) for the range
>>      * @return an array of {@code PathElement} which can be used to create a {@code Shape}
>>      * @since 25
>>      */
>>     public final PathElement[] strikeThroughShape(int start, int end)
>> 
>> 
>> 
>> 
>> ## WARNING
>> 
>> 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) ).
>> 
>> 
>> 
>> ## 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 with a new target base due to a merge or a rebase. The pull request now contains 42 commits:
> 
>  - Merge remote-tracking branch 'origin/master' into ag.text.layout.api
>  - review comments
>  - Merge remote-tracking branch 'origin/master' into ag.text.layout.api
>  - 25 25
>  - Merge branch 'master' into ag.text.layout.api
>  - Merge remote-tracking branch 'origin/master' into ag.text.layout.api
>  - Merge remote-tracking branch 'origin/master' into ag.text.layout.api
>  - Merge branch 'master' into ag.text.layout.api
>  - segments
>  - Merge remote-tracking branch 'origin/master' into ag.text.layout.api
>  - ... and 32 more: https://git.openjdk.org/jfx/compare/fc770fb9...0f94efdd

modules/javafx.graphics/src/main/java/com/sun/javafx/scene/text/TextLayout.java line 256:

> 254:      * @return the caret geometry
> 255:      */
> 256:     public float[] getCaretGeometry(int offset, boolean leading);

Does this method throw any exceptions? If so, please specify.

modules/javafx.graphics/src/main/java/com/sun/javafx/scene/text/TextLayout.java line 271:

> 269:      * @param client the callback to invoke for each rectangular shape
> 270:      */
> 271:     public void getRange(int start, int end, int type, GeometryCallback client);

Does this method throw any exceptions?

modules/javafx.graphics/src/main/java/javafx/scene/text/LayoutInfo.java line 41:

> 39:  * @since 25
> 40:  */
> 41: public abstract class LayoutInfo {

Any exceptions thrown by methods of this class?

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

PR Review Comment: https://git.openjdk.org/jfx/pull/1596#discussion_r1986028504
PR Review Comment: https://git.openjdk.org/jfx/pull/1596#discussion_r1986028592
PR Review Comment: https://git.openjdk.org/jfx/pull/1596#discussion_r1986029390