The at command highlights notes in the notation editor and adds a mark signifier to the note's data token in the text editor.

Pressing @ while a note is selected will mark the note with a user-signifier based on the last marked-note RDF line in the Humdrum data with a form such as:

!!!RDF**kern: @ = marked note

If there is no marked-note RDF definition in the Humdrum data, one will be added automatically to the end of the data. Here is an example of marking notes in the notation, which adds @ to the note tokens in the Humdrum data.

marking notes in graphic notation editor.
Marking notes with @ in the notation editor.

Changing mark colors

The default color for marked notes in VHV notation is red. If you want to use another color, a color parameter can be added to the RDF:

marking notes in graphic notation editor in different colors.
Changing the color of marked notes.

The color parameter value should be enclosed in quotes if it contains spaces, but otherwise the quotes are optional. Colors can be

named colors as well as transparent, or any numeric format recognized by SVG: 3/6 digit hexadecimal colors, RGB colors, RGBA colors, HSL colors, or HSLA colors. Examples:

example of hex color.
Example of hex color "#c03da2".

The same color in rgb format:

example of hex color.
Example of rgb color "rgb(192,61,162)".

Adding 50% opacity to the same color in rgba format:

example of hex color.
Example of rgb color "rgb(192,61,162,0.5)".

Multiple marks

Any number of RDF marks can be given in the data. The last marked-note RDF in the data will be the one that the at command uses when marking notes:

example of two mark colors.
Example second mark (coral colored notes).

In this case there are two RDF marking lines:

!!!RDF**kern: @ = marked note color=turquoise
!!!RDF**kern: N = marked note color=coral

Since the last one uses N for the mark, typing at will add the character N to the marked note tokens rather than @.

Meaning of the mark

RDF records are free-form texts, so you can add your own text to the line which explains the meaning of the mark.

!!!RDF**kern: @ = marked note color="orchid" strange note

If you want a more formalized system, then use meaning="...":

!!!RDF**kern: @ = marked note color="orchid" meaning="strange note"

This parameter does not yet have any meaning in VHV itself yet, but perhaps it could be mapped to a tooltip on the note in the future.

SVG class attribute

In the SVG notation, marked notes are also labeled with the class marked. This class tag can be used to change the color and styling of the notes with CSS if the SVG image is placed directly into an HTML document (rather than loaded with an <image> element):

The above image was created by first marking the notes in VHV, then saving the SVG (SVG code made visible with alt-g) then inserted directly into the HTML page, using this CSS styling:

   svg .note.marked { filter: url(#DropShadow); }
   svg .note.marked rect { fill: red; }
   svg .note.marked  use { fill: url(#MyHighlight); }

And adding these filters to the top of the SVG:

<defs id="#myDefs">
   <linearGradient id="MyHighlight">
      <stop offset="0%" stop-color="yellow"/>
      <stop offset="100%" stop-color="red"/>
   <filter id="DropShadow" height="130%" width="300%">
      <feGaussianBlur in="SourceAlpha" stdDeviation="20"/>
      <feOffset dx="30" dy="30" result="offsetblur"/>
         <feMergeNode in="SourceGraphic"/>