Java SWT overlapping/multiple StyleRanges

Question

I'm using a StyledText in my project, in it I have lots of texts that can have different styles depending on some events, sometimes these styles can overlap, so a style that represents a yellow background color can be set for an area that already has a styleRange of a red foreground color.

Here's an example in code that's not representative of the closed source project:

        text_1 = new StyledText(composite, SWT.BORDER);
        text_1.setBounds(10, 10, 320, 21);
        text_1.setText("1234567890abcdefghij");
        text_1.setStyleRange(new StyleRange(0, 9, Display.getDefault().getSystemColor(SWT.COLOR_RED), null));
        text_1.setStyleRange(new StyleRange(2, 9, null,  Display.getDefault().getSystemColor(SWT.COLOR_YELLOW)));
        text_1.setSelection(3, 7);

The first style from 0-9 is to have a red foreground color, the second for 2-9 is to have a yellow background, what I get is that only 0-1 will have a red foreground color, while 2-9 will have black foreground color with yellow background, when what I want is 2-9 to have both a red foreground and a yellow background.

Result:

What I want it to look like:

My question, how can I make it so that setting a new styleRange doesn't erase the old style range or at least copies previous characteristics in case one was null?

Thank you.

You might also want to see if you can use a LineStyleListener, if that's closer to how you want to operate. — nitind, Apr 18 '17 at 01:29

score 4 · Answer 1 · answered Apr 17 '17 at 13:58

The JavaDoc of setStyleRange() pretty much says it all:

The new style overwrites existing styles for the specified range. Existing style ranges are adjusted if they partially overlap with the new style

This means that you'll have to define each part individually:

Red text, white background
Red text, yellow background

score 4 · Accepted Answer · answered Apr 17 '17 at 13:59

4

Style ranges can't overlap. You will have to write code to combine the ranges where they overlap to achieve what you want.

If you can use JFace the TextPresentation class can merge overlapping ranges. You can use this on its own and in combination with the TextViewer or SourceViewer classes.

answered Apr 17 '17 at 13:59

greg-449

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Thanks for the answer, I'm looking into making the code check for existing ranges and somehow combine them, although I'm worried my implantation wouldn't be so concrete as something already established. I looked at TextPresentation, seems like a good thing if I can use applyTextPresentation on my StyledText after using mergeRanges, would this be the correct use or is using StyledText not optimal? I never used TextViewer/SourceViewer being quite new to SWT in general. – thinkereer Apr 18 '17 at 06:37
TextPresentation is intended to work with StyledText so yes this is OK. – greg-449 Apr 18 '17 at 06:41
In the end what you said is the correct answer, I tried it out and I can merge styles, regardless if that works out with how my code is and the different scenarios, it's indeed the answer. Answer accepted, thank you very much! You rock! – thinkereer Apr 19 '17 at 06:34

Java SWT overlapping/multiple StyleRanges

2 Answers2