Test: Terminal underline styles and colors

[Tyriar]

Refs: #156983

• macOS @aeschli
• linux @TylerLeonhardt

Complexity: 3

Authors: @meganrogge @Tyriar

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The terminal now supports escape sequences for different styles of underline as well as full color support. Here are some docs on the feature https://sw.kovidgoyal.net/kitty/underlines/. In addition to this, when GPU acceleration is using the webgl renderer (on/auto), we do improved underlining by not overlapping with the glyphs:

Basic usage (echo -e "<string>"):

# Previously supported underline sequences
\x1b[4m    # straight underline
\x1b[24m   # no underline

# Underline styles
\x1b[4:0m  # no underline
\x1b[4:1m  # straight underline
\x1b[4:2m  # double underline
\x1b[4:3m  # curly underline
\x1b[4:4m  # dotted underline
\x1b[4:5m  # dashed underline

# Underline colors (a style is required)
\x1b[58:5:32m            # 256 color palette: ANSI color number 32, see https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit
\x1b[58:2:0:255:128:64m  # True color: Red=255, Green=128, Blue=64
\x1b[59m                 # reset color

Ensure all of the above sequences work as expected and look good, some things to tweak while testing:

• terminal.integrated.gpuAcceleration ("on" or "canvas", this will not work when "off" is used)
• terminal.integrated.fontSize
• window.zoomLevel
• The cells look correct when selected
• Scroll up and down

This feature does not work on Windows because of a limitation in conpty.

[TylerLeonhardt]

Love it!

[TylerLeonhardt]

The script I used to test this:

# Previously supported underline sequences
$straight1 = "`e[4m"    # straight underline
$none1 = "`e[24m"   # no underline

# Underline styles
$none2 = "`e[4:0m"  # no underline
$straight2 = "`e[4:1m"  # straight underline
$double = "`e[4:2m"  # double underline
$curly = "`e[4:3m"  # curly underline
$dotted = "`e[4:4m"  # dotted underline
$dashed = "`e[4:5m"  # dashed underline

# Underline colors (a style is required)
$color1 = "`e[58:5:32m"            # 256 color palette: ANSI color number 32, see https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit
$color2 = "`e[58:2:0:255:128:64m"  # True color: Red=255, Green=128, Blue=64
$noColor = "`e[59m"                 # reset color

function emit($text) {
    # Change this to a different color or different none
    "$color2$text$none2$noColor"
}

$allTheText = "abcdefghijklmnopqrstuvwxyz1234567890-=`~!@#$%^&*()_+[]\{}|;':`"/? 👽 現代"
emit ($straight1 + $allTheText)
emit ($straight2 + $allTheText)
emit ($double + $allTheText)
emit ($curly + $allTheText)
emit ($dotted + $allTheText)
emit ($dashed + $allTheText)