package require tkpath
namespace eval ::ix {
    proc random_int {} {return [expr "int(floor(rand()*16))"]}
    proc random_clr {} {
        return [format "\#%1X%1X%1X%1X%1X%1X" [random_int] [random_int] [random_int] [random_int] [random_int] [random_int]]
    }
    variable _

    proc mat_click {what p t x y} {
	variable _
	switch $what {
	    motion {
		foreach xy {x y} {
		    set mv [mat_tr $p $t $xy d [expr $$xy - $_($t:c$xy)]]
		    foreach ab {a b} {
			set _($t:${xy}$ab) [expr $_($t:${xy}$ab) - $mv]
		    }
		    mat_gridlines $p $t
		}
	    }
	}
	foreach xy {x y}  {set _($t:c$xy) [set $xy]}
    }
    proc mat_tr {p t d inv v} {
	variable _
	array set dm {x width y height}
	switch $inv {
	    t {return [expr ($v - $_($t:${d}a)) / ($_($t:${d}b) - $_($t:${d}a) + 0.0) * [winfo $dm($d) $p.m]]}
	    i {return [expr ($_($t:${d}b) - $_($t:${d}a)) * $v /([winfo $dm($d) $p.m] + 0.0) + $_($t:${d}a)]}
	    d {return [expr ($_($t:${d}b) - $_($t:${d}a)) * $v /([winfo $dm($d) $p.m] + 0.0)]}
	}
    }
    proc mat_new {path target w h bg ln Xa Xb Ya Yb qXv qYv} {
	variable _
	set _($target:ln) $ln
	set _($target:qxv) $qXv
	set _($target:qyv) $qYv
	set _($target:ya) $Ya
	set _($target:xa) $Xa
	set _($target:yb) $Yb
	set _($target:xb) $Xb
	if {[winfo exists $path.m] != 1} {
	    canvas $path.m -bg $bg -width $w -height $h
	    pack $path.m -side left
	    bind $path.m <1> "::ix::mat_click first $path $target %x %y"
	    bind $path.m <B1-Motion> "::ix::mat_click motion $path $target %x %y"
	    bind $path.m <ButtonRelease-1> "::ix::mat_click release $path $target %x %y"
	    mat_gridlines $path $target
	    set bd [expr {[$path cget -bd] * 2}]
            $path configure -bg gray -width [expr [winfo width $path.m] + $bd] \
		-height [expr [winfo height $path.m] + $bd]}}
    
    proc mat_gridlines {path target} {
	variable _
#	puts gridlines
	set w $path.m
	$w delete gridlines
	set gh [winfo height $w]
	set gw [winfo width $w]
	foreach item [$path.m find withtag gridline] {$path.m delete $item}
	foreach xy {x y} {
	    array set ta {x n y w}
	    array set tj {x center y left}
	    array set igx {y width x height}
	    for {set x [expr int($_($target:${xy}a) / ($_($target:q${xy}v) + 0.0) + 1)*($_($target:q${xy}v) + 0.0)]} {$x <= $_($target:${xy}b)} {set x [expr $x + $_($target:q${xy}v)]} {
		set og [mat_tr $path $target $xy t $x]
		set invgeo [winfo $igx($xy) $path.m]
		switch $xy {y {set coords [concat M 0 $og L $invgeo $og]}
		    x {set coords [concat M $og 0 L $og $invgeo]}}
		$w create path $coords -stroke $_($target:ln) -strokedasharray 2 -tags gridline -strokewidth 1
		$w create text [lrange $coords 1 2] -font {{Bitstream Vera Sans} 8} \
		    -fill green -anchor $ta($xy) -text $x -justify $tj($xy) -tags gridline}}
    }
}
#> mat frame
#. -bd 3 #w 384 #h 144 #bg white #ln purple
#. #Xa 123 #Xb 2000 #Ya 0 #Yb 127 #qXv 125 #qYv 1
#. @list  ::ix::mat_add .- .| {.#1} .#2 .#3 .#4
#. @add  ::ix::mat_add .- .| {.#1} .#2 .#3 .#4
puts "mat .- .|"
::ix::mat_new .- .| .#w .#h .#bg .#ln .#Xa .#Xb .#Ya .#Yb .#qXv .#qYv