# plot.tcl --

#

# This demonstration script creates a canvas widget showing a 2-D

# plot with data points that can be dragged with the mouse.

#

# RCS: @(#) $Id: plot.tcl,v 1.3 2001/06/14 10:56:58 dkf Exp $

if {![info exists widgetDemo]} {

    error "This script should be run from the \"widget\" demo."

}

set w .plot

catch {destroy $w}

toplevel $w

wm title $w "Plot Demonstration"

wm iconname $w "Plot"

positionWindow $w

set c $w.c

label $w.msg -font $font -wraplength 4i -justify left -text "This window displays a canvas widget containing a simple 2-dimensional plot.  You can doctor the data by dragging any of the points with mouse button 1."

pack $w.msg -side top

frame $w.buttons

pack $w.buttons -side bottom -fill x -pady 2m

button $w.buttons.dismiss -text Dismiss -command "destroy $w"

button $w.buttons.code -text "See Code" -command "showCode $w"

pack $w.buttons.dismiss $w.buttons.code -side left -expand 1

canvas $c -relief raised -width 450 -height 300

pack $w.c -side top -fill x

set plotFont {Helvetica 18}

$c create line 100 250 400 250 -width 2

$c create line 100 250 100 50 -width 2

$c create text 225 20 -text "A Simple Plot" -font $plotFont -fill brown

for {set i 0} {$i <= 10} {incr i} {

    set x [expr {100 + ($i*30)}]

    $c create line $x 250 $x 245 -width 2

    $c create text $x 254 -text [expr {10*$i}] -anchor n -font $plotFont

}

for {set i 0} {$i <= 5} {incr i} {

    set y [expr {250 - ($i*40)}]

    $c create line 100 $y 105 $y -width 2

    $c create text 96 $y -text [expr {$i*50}].0 -anchor e -font $plotFont

}

foreach point {

    {12 56} {20 94} {33 98} {32 120} {61 180} {75 160} {98 223}

} {

    set x [expr {100 + (3*[lindex $point 0])}]

    set y [expr {250 - (4*[lindex $point 1])/5}]

    set item [$c create oval [expr {$x-6}] [expr {$y-6}] \

	    [expr {$x+6}] [expr {$y+6}] -width 1 -outline black \

	    -fill SkyBlue2]

    $c addtag point withtag $item

}

$c bind point <Any-Enter> "$c itemconfig current -fill red"

$c bind point <Any-Leave> "$c itemconfig current -fill SkyBlue2"

$c bind point <1> "plotDown $c %x %y"

$c bind point <ButtonRelease-1> "$c dtag selected"

bind $c <B1-Motion> "plotMove $c %x %y"

set plot(lastX) 0

set plot(lastY) 0

# plotDown --

# This procedure is invoked when the mouse is pressed over one of the

# data points.  It sets up state to allow the point to be dragged.

#

# Arguments:

# w -		The canvas window.

# x, y -	The coordinates of the mouse press.

proc plotDown {w x y} {

    global plot

    $w dtag selected

    $w addtag selected withtag current

    $w raise current

    set plot(lastX) $x

    set plot(lastY) $y

}

# plotMove --

# This procedure is invoked during mouse motion events.  It drags the

# current item.

#

# Arguments:

# w -		The canvas window.

# x, y -	The coordinates of the mouse.

proc plotMove {w x y} {

    global plot

    $w move selected [expr {$x-$plot(lastX)}] [expr {$y-$plot(lastY)}]

    set plot(lastX) $x

    set plot(lastY) $y

}