How to set a different background color for the text before a certain line?

SuperCPU

Hello everyone,
Sorry if this was asked before, I posted the question on GitHub first, and I was redirected here - https://github.com/notepad-plus-plus/notepad-plus-plus/issues/17099
I am editing a text file where the most important part starts after a line containing only the word STARTCODE
Can Notepad++ change the background color for the text before that? For example, to make it light gray, so I know those lines are not important. Or is it possible to do it with a plugin?

PeterJones

@SuperCPU ,

The Notepad++ UDL system isn’t quite up to the task by itself, because there’s no way to say “highlight from beginning of line to here if this matches”.

But there are two ways I can think of, using plugins.

First, I know the AnalysePlugin has the ability to apply multiple regular expressions to the same file; I don’t use it, but there might be a way to have it automatically apply colors based on the regular expression (but I’m not 100% sure, so you might need to experiment) – but a regex like ^.*STARTCODE should mark from the beginning of the line until the STARTCODE

Second (and this one I’m more confident of): you could use the UDL feature of Notepad++ in combination with the EnhanceAnyLexer plugin. That plugin defines its rules based on the lexer language (whether it’s a builtin language like Python or a UDL for your custom needs), and doesn’t actually care whether the UDL has any keywords (though you might want to define STARTCODE as a keyword). But with that plugin, you can define a foreground color

[normal text]
0x777777 = ^.*STARTCODE

[exact name of UDL]
0x777777 = ^.*STARTCODE

(My screenshot shows it in the [normal text] section, since I didn’t want to create a new UDL for this example, but if you’ve got a UDL called exact name of UDL, then the second section in my post would do it.)

I had seen your Issue earlier, so already had a mental plan of what I’d say if you ever posted here. But while I was typing up this reply, I realized that maybe my first interpretation was wrong. If you had the text,

before
before
xyz STARTCODE
blah
blah

were you intending the gray text to just be the xyz STARTCODE, or did you want to also gray out the before lines?

If the latter, then your EnhanceAnyLexer line would be more like,

0xcccccc = (?s)\A.*\bSTARTCODE\b

(Either way, make sure to not set the excluded_styles = #, #, .... unless you want to exclude your regex from working when inside one of the other UDL styles. It’s more powerful to be able to restrict it, but for new users, it usually makes more sense to just leave that option out.)

I hope one of these is what you want.

SuperCPU

@PeterJones
Thank you for your reply and for all the effort to answer my question!

Sorry I wasn’t clear enough: I wanted to say that I want to change the background color for all the lines before that line containing the word STARTCODE, so your second answer is what I need.
However, it works but once I close the EnhanceAnyLexerConfig.ini or I simply start editing the “startcode.txt” file, the graying is gone for those lines before STARTCODE

And another question is: how can I change the background color instead of the ink color?

PeterJones

However, it works but once I close the EnhanceAnyLexerConfig.ini or I simply start editing the “startcode.txt” file, the graying is gone for those lines before STARTCODE

Once you save the config, assuming you used [normal text], then the next time you open a text file, it will use that rule. So if you close startcode.txt and reopen it, it should work right.

And another question is: how can I change the background color instead of the ink color?

EnhanceAnyLexer only affects foreground colors, not background colors. Sorry.

mpheath

@SuperCPU

LuaScript plugin code added to startup.lua can add an indicator from the start of document up to the start of the line with STARTCODE.

function Event_StartCodeTag()
    -- Add indicator from position 0 to start position of STARTCODE.

    if editor.LexerLanguage == 'null' then
        local indic = 3

        if editor:IndicatorEnd(indic, 0) == 0 then
            local start_pos = editor:findtext('^STARTCODE$', SCFIND_REGEXP |
                                                             SCFIND_MATCHCASE)
            if start_pos then
                editor.IndicatorCurrent = indic
                editor:IndicatorClearRange(0, start_pos)
                editor.IndicStyle[indic] = INDIC_ROUNDBOX
                editor.IndicFore[indic] = 0xC0C0C0
                editor.IndicAlpha[indic] = 100
                editor:IndicatorFillRange(0, start_pos)
            end
        end
    end
end

function Event_Ready()
    -- Called when the editor is ready.

    Event_StartCodeTag()
    npp.AddEventHandler('OnSwitchFile', Event_StartCodeTag)
end

npp.AddEventHandler('OnReady', Event_Ready)

This will try to handle any document using the null lexer. That is the None (Normal Text) item in the Language menu.

It is set to use indicator 3 with a INDIC_ROUNDBOX style with a colour of 0xC0C0C0 which is light grey. The alpha is 100 and can be set between 0 and 255. The OnReady event is to ensure the indicators are not being applied until Notepad++ is ready.

Viewed with the default theme:

Other scripting plugins should be able to apply indicators with similar code.