Test for Label overrun

Question

I have a multiline label whose text has a chance of overrunning. If it does this, I want to decrease the font size until it isn\'t overrunning, or until it hits some minimum siz

Answer 1

It's already been mentioned by Johann that you can use (Text)labeled.lookup(".text") to get the actual displayed text for a Label, then compare it to the intended String... However, in my case, this did not work. Perhaps it was because I was updating the Label with a high frequency, but the actual String was always a few chars less than the intended...

So, I opted to use the setEllipsisString(String value) method to set the ellipsis string (what's appended to the end of a Label when there's overrun, the default being "...") to an (unused) ASCII control character like 0x03 (appropriately named "end of text"), then after each time I set the Label text I check if the last char of the actual String is the control char.

Example using Platform.runLater(Runnable):

import javafx.scene.control.Label;
import javafx.application.Platform;
import javafx.scene.text.Text;
...
Label label = new Label();
...
label.setEllipsisString("\003");
...
final String newText = "fef foo";
Platform.runLater(() -> {
    label.setText(newText);
    String actual = ((Text)label.lookup(".text")).getText();
    // \003 is octal for the aforementioned "end of text" control char
    if (actual.length() > 0 && actual.charAt(actual.length()-1) == '\003') {
        // Handle text now that you know it's clipped
    }
});

Note that you can set the control char to anything really, and it doesn't need to be just one char; however if you opt for a control character, check that it isn't commonly used.