RFR: 8304831: TextFlow.hitTest.insertionIndex incorrect with surrogate pairs [v3]

[Karthik P K]

On Tue, 9 May 2023 18:16:09 GMT, Andy Goryachev <angorya at openjdk.org> wrote:

>> Karthik P K has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Address code review
>
> modules/javafx.graphics/src/main/java/com/sun/javafx/text/PrismTextLayout.java line 425:
> 
>> 423:     public Hit getHitInfo(float x, float y) {
>> 424:         int charIndex = -1;
>> 425:         int insertionIndex = -1;
> 
> [question]
> 
> Currently, there are a few scenarios when a negative insertionIndex is passed down to HitInfo.  This will trigger a similar (and probably incorrect) computation of the insertion index in HitInfo, see for example [JDK-8302511](https://bugs.openjdk.org/browse/JDK-8302511).
> 
> My question is - should we instead resolve the insertion index always?

After current fix, only scenario where `insertionIndex` not getting initialized will be when `lineIndex >= getLineCount()` is true. So even if `insertionIndex` -1, text will be null and `HitInfo.getInsertionIndex()` will not have any computation to perform. So we can resolve the insertion index always I think. Please let me know your thoughts on this.

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PR Review Comment: https://git.openjdk.org/jfx/pull/1091#discussion_r1190682049