# ruler.tcl --

#

# This demonstration script creates a canvas widget that displays a ruler

# with tab stops that can be set, moved, and deleted.

#

# RCS: @(#) $Id: ruler.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."

}

# rulerMkTab --

# This procedure creates a new triangular polygon in a canvas to

# represent a tab stop.

#

# Arguments:

# c -		The canvas window.

# x, y -	Coordinates at which to create the tab stop.

proc rulerMkTab {c x y} {

    upvar #0 demo_rulerInfo v

    $c create polygon $x $y [expr {$x+$v(size)}] [expr {$y+$v(size)}] \

	    [expr {$x-$v(size)}] [expr {$y+$v(size)}]

}

set w .ruler

global tk_library

catch {destroy $w}

toplevel $w

wm title $w "Ruler Demonstration"

wm iconname $w "ruler"

positionWindow $w

set c $w.c

label $w.msg -font $font -wraplength 5i -justify left -text "This canvas widget shows a mock-up of a ruler.  You can create tab stops by dragging them out of the well to the right of the ruler.  You can also drag existing tab stops.  If you drag a tab stop far enough up or down so that it turns dim, it will be deleted when you release the mouse button."

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 -width 14.8c -height 2.5c

pack $w.c -side top -fill x

set demo_rulerInfo(grid) .25c

set demo_rulerInfo(left) [winfo fpixels $c 1c]

set demo_rulerInfo(right) [winfo fpixels $c 13c]

set demo_rulerInfo(top) [winfo fpixels $c 1c]

set demo_rulerInfo(bottom) [winfo fpixels $c 1.5c]

set demo_rulerInfo(size) [winfo fpixels $c .2c]

set demo_rulerInfo(normalStyle) "-fill black"

if {[winfo depth $c] > 1} {

    set demo_rulerInfo(activeStyle) "-fill red -stipple {}"

    set demo_rulerInfo(deleteStyle) [list -fill red \

	    -stipple @[file join $tk_library demos images gray25.bmp]]

} else {

    set demo_rulerInfo(activeStyle) "-fill black -stipple {}"

    set demo_rulerInfo(deleteStyle) [list -fill black \

	    -stipple @[file join $tk_library demos images gray25.bmp]]

}

$c create line 1c 0.5c 1c 1c 13c 1c 13c 0.5c -width 1

for {set i 0} {$i < 12} {incr i} {

    set x [expr {$i+1}]

    $c create line ${x}c 1c ${x}c 0.6c -width 1

    $c create line $x.25c 1c $x.25c 0.8c -width 1

    $c create line $x.5c 1c $x.5c 0.7c -width 1

    $c create line $x.75c 1c $x.75c 0.8c -width 1

    $c create text $x.15c .75c -text $i -anchor sw

}

$c addtag well withtag [$c create rect 13.2c 1c 13.8c 0.5c \

	-outline black -fill [lindex [$c config -bg] 4]]

$c addtag well withtag [rulerMkTab $c [winfo pixels $c 13.5c] \

	[winfo pixels $c .65c]]

$c bind well <1> "rulerNewTab $c %x %y"

$c bind tab <1> "rulerSelectTab $c %x %y"

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

bind $c <Any-ButtonRelease-1> "rulerReleaseTab $c"

# rulerNewTab --

# Does all the work of creating a tab stop, including creating the

# triangle object and adding tags to it to give it tab behavior.

#

# Arguments:

# c -		The canvas window.

# x, y -	The coordinates of the tab stop.

proc rulerNewTab {c x y} {

    upvar #0 demo_rulerInfo v

    $c addtag active withtag [rulerMkTab $c $x $y]

    $c addtag tab withtag active

    set v(x) $x

    set v(y) $y

    rulerMoveTab $c $x $y

}

# rulerSelectTab --

# This procedure is invoked when mouse button 1 is pressed over

# a tab.  It remembers information about the tab so that it can

# be dragged interactively.

#

# Arguments:

# c -		The canvas widget.

# x, y -	The coordinates of the mouse (identifies the point by

#		which the tab was picked up for dragging).

proc rulerSelectTab {c x y} {

    upvar #0 demo_rulerInfo v

    set v(x) [$c canvasx $x $v(grid)]

    set v(y) [expr {$v(top)+2}]

    $c addtag active withtag current

    eval "$c itemconf active $v(activeStyle)"

    $c raise active

}

# rulerMoveTab --

# This procedure is invoked during mouse motion events to drag a tab.

# It adjusts the position of the tab, and changes its appearance if

# it is about to be dragged out of the ruler.

#

# Arguments:

# c -		The canvas widget.

# x, y -	The coordinates of the mouse.

proc rulerMoveTab {c x y} {

    upvar #0 demo_rulerInfo v

    if {[$c find withtag active] == ""} {

	return

    }

    set cx [$c canvasx $x $v(grid)]

    set cy [$c canvasy $y]

    if {$cx < $v(left)} {

	set cx $v(left)

    }

    if {$cx > $v(right)} {

	set cx $v(right)

    }

    if {($cy >= $v(top)) && ($cy <= $v(bottom))} {

	set cy [expr {$v(top)+2}]

	eval "$c itemconf active $v(activeStyle)"

    } else {

	set cy [expr {$cy-$v(size)-2}]

	eval "$c itemconf active $v(deleteStyle)"

    }

    $c move active [expr {$cx-$v(x)}] [expr {$cy-$v(y)}]

    set v(x) $cx

    set v(y) $cy

}

# rulerReleaseTab --

# This procedure is invoked during button release events that end

# a tab drag operation.  It deselects the tab and deletes the tab if

# it was dragged out of the ruler.

#

# Arguments:

# c -		The canvas widget.

# x, y -	The coordinates of the mouse.

proc rulerReleaseTab c {

    upvar #0 demo_rulerInfo v

    if {[$c find withtag active] == {}} {

	return

    }

    if {$v(y) != $v(top)+2} {

	$c delete active

    } else {

	eval "$c itemconf active $v(normalStyle)"

	$c dtag active

    }

}