CodeArea: too frequent model updates

[PavelTurk]

Hello, Andy

I've made sure to formulate everything very precisely and just created a new issue. Unfortunately I know only its ID: 9078451.

If my proposal is incorrect - then this issue is not meant to be resolved. However, I'm certain this is an important question regardless.

Best regards, Pavel

On 4/30/25 17:45, Andy Goryachev wrote:
>
> Dear Pavel:
>
> As I mentioned before, the view might request more paragraphs than currently visible, so it works as designed.
>
> When you say it's slow, could you tell what metric / measurement you used?  The attached code does not appear slow on my macOS.  Would you provide a reproducer which can illustrate the issue?
>
> Thanks
>
> -andy
>
> *From: *openjfx-dev <openjfx-dev-retn at openjdk.org> on behalf of PavelTurk <pavelturk2000 at gmail.com>
> *Date: *Wednesday, April 30, 2025 at 04:14
> *To: *openjfx-dev at openjdk.org <openjfx-dev at openjdk.org>
> *Subject: *CodeArea: too frequent model updates
>
> Trying to understand why my Jfx CodeArea works so slowly I wrote a test application (see below).
> And I got interesting results. If you start the application you will see that about 10 paragraphs
> are visible.
>
> 1. If after start you click on the report button you will see that about 113 paragraphs were created (remember 10 visible).
> 2. If you click event button (as I understand to update only 15 paragraphs - I can be wrong here) in the report you will see 112 paragraphs.
> 3. If you scroll to line 100, click report to clear, add one letter via keyboard and in the new report you will see 210 paragraphs were updated.
> So, with one paragraph modified and 10 paragraphs visible CodeArea updates 210 paragraphs.
>
> I see two solutions here:
> 1) If Jfx CodeArea wants to update paragraphs itself it should be optimized
> 2) A better solution is to remove final modifier from CodeTextModel.getParagraph(int index) method so that we could override it.
>
> public class JfxTextArea extends Application {
>
>      @Override
>      public void start(Stage primaryStage) throws Exception {
>          CodeArea codeArea = new CodeArea();
>          codeArea.setLineNumbersEnabled(true);
>          final List<Integer> requestedIndexes = new ArrayList<>();
>          codeArea.setSyntaxDecorator(new SyntaxDecorator() {
>              @Override
>              public RichParagraph createRichParagraph(CodeTextModel ctm, int i) {
>                  requestedIndexes.add(i);
>                  RichParagraph.Builder b = RichParagraph.builder();
>                  b.addSegment(ctm.getPlainText(i));
>                  return b.build();
>              }
>
>              @Override
>              public void handleChange(CodeTextModel ctm, TextPos tp, TextPos tp1, int i, int i1, int i2) {
>
>              }
>          });
>          StringBuilder sb = new StringBuilder();
>          for (var i = 0; i < 1000; i++) {
>              sb.append(i);
>              sb.append("\n");
>          }
>          codeArea.setText(sb.toString());
>
>          var reportButton = new Button("Report & Clear");
>          reportButton.setOnAction(e -> {
>              Collections.sort(requestedIndexes);
>              System.out.println("Created/Updated " + requestedIndexes.size() + " paragraphs: " + requestedIndexes);
>              requestedIndexes.clear();
>          });
>          var topButton = new Button("To Top");
>          topButton.setOnAction(e -> codeArea.select(new TextPos(0, 0, 0, true)));
>          var bottomButton = new Button("To Bottom");
>          bottomButton.setOnAction(e -> codeArea.select(new TextPos(999, 0, 0, true)));
>          var eventButton = new Button("Fire Event");
>          eventButton.setOnAction(e -> codeArea.getModel()
>                  .fireStyleChangeEvent(new TextPos(0, 0, 0, true), new TextPos(15, 0, 0, true)));
>          HBox buttonBox = new HBox(reportButton, topButton, bottomButton, eventButton);
>
>          VBox.setVgrow(codeArea, Priority.ALWAYS);
>          VBox root = new VBox(codeArea, buttonBox);
>          Scene scene = new Scene(root, 600, 200);
>          primaryStage.setScene(scene);
>          primaryStage.show();
>
>      }
>
>      public static void main(String[] args) {
>          launch(args);
>      }
>
> }
>
> Best regards, Pavel
>
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