# -*- tcl -*- tcl.tk//DSL diagram//EN//1.0

set movelength [1 cm]

proc  filter {args} {box height [1 cm] {*}$args}

set Top [block {
    right
    box "ms" "sources"
    move
    box "HTML" "sources"
    move
    box "linuxdoc-sgml" "sources" width [3 cm]
    move
    box "Texinfo" "sources"

    line down from [1st box s]
    set A [line down]
    line down from [2nd box s]; filter "html2ms"
    set B [line down]
    line down from [3rd box s]; filter "format"
    set C [line down]
    line down from [4th box s]; filter "texi2roff"
    set D [line down]
}]
move down from [last block s]
set Anchor [box width [4 cm] "ms" "intermediate" "form"]
arrow from [$Top A end] to [$Anchor nw]
arrow from [$Top B end] to [.33 between [$Anchor nw] [$Anchor ne]]
arrow from [$Top C end] to [.67 between [$Anchor nw] [$Anchor ne]]
arrow from [$Top D end] to [$Anchor ne]
group {
    # PostScript column
    move to [$Anchor sw]
    arrow down left then down
    filter "pic"
    arrow
    filter "eqn"
    arrow
    filter "tbl"
    arrow
    filter "groff"
    arrow
    box "PostScript"

    # HTML column
    move to [$Anchor se]
    arrow down right then down
    set A [filter dotted "pic2img"]
    arrow
    set B [filter dotted "eqn2html"]
    arrow
    set C [filter dotted "tbl2html"]
    arrow
    filter "ms2html"
    arrow
    box "HTML"

    # Nonexistence caption
    box dashed width [3 cm] at [$B + [[6 cm] 0]] "These tools" "don’t yet exist"
    arrow chop 10 dashed from [last box nw] to [$A e]
    arrow chop 10 dashed from [last box w]  to [$B e]
    arrow chop 10 dashed from [last box sw] to [$C e]
}