# editgraph.tcl --
 #     Widget to edit data series graphically
 #
 #     Note:
 #     Not as elegant as could be with bindings via Plotchart itself
 #
 package require Plotchart
 
 namespace eval ::Editgraph {

     variable graph
     variable endedit
 }

 # editSeries --
 #     Procedure to edit a series of data graphically
 #
 # Arguments:
 #     xrange          Range for the x values
 #     yrange          Range for the y values
 #     number          Number of data points
 #
 # Result:
 #     List of x,y values representing the data series
 #
 # Note:
 #     The widget allows setting new y values for given x values only
 #
 proc ::Editgraph::editSeries {xrange yrange number} {

     variable graph
     variable endedit

     toplevel .graph
     wm title .graph "Editing series"
     canvas   .graph.c -width 400 -height 300
     button   .graph.ok     -text OK     -width 10 -command {::Editgraph::SaveSeries}
     button   .graph.cancel -text Cancel -width 10 -command {::Editgraph::CancelSeries}
     grid     .graph.c -
     grid     .graph.ok .graph.cancel

     #
     # Initialise the series
     #
     foreach {xmin xmax} $xrange {break}
     foreach {ymin ymax} $yrange {break}

     if { $ymin <= 0.0 && $ymax >= 0.0 } {
         set y 0.0
     } else {
         set y $ymin
     }

     set delx [expr {($xmax-$xmin)/double($number-1)}]

     set graph(xy) {}
     set x         $xmin
     while { $x < $xmax+0.5*$delx } {
         lappend graph(xy) $x $y
         set x [expr {$x + $delx}]
         if { abs($x) < 0.5 *$delx } {
             set x 0.0
         }
     }
     set graph(xmin)   $xmin
     set graph(xmax)   $xmax
     set graph(delx)   $delx
     set graph(number) $number

     set graph(plot) [::Plotchart::createXYPlot .graph.c \
                         [::Plotchart::determineScale $xmin $xmax] \
                         [::Plotchart::determineScale $ymin $ymax]]

     $graph(plot) dataconfig data -colour blue
     set graph(widget) .graph.c

     foreach {x y} $graph(xy) {
         $graph(plot) plot data $x $y
     }

     #
     # Set the bindings
     #
     # bind .graph.c <Button-1> {::Editgraph::EditPoint %W %x %y}
     bind .graph.c <ButtonPress-1> {
         ::Editgraph::EditPoint %W %x %y
         bind %W <Motion> {::Editgraph::EditPoint %W %%x %%y}
     }
     bind .graph.c <ButtonRelease-1> {
         bind %W <Motion> {}
     }


     vwait ::Editgraph::endedit
     puts "$endedit"

     if { $endedit == 1 } {
         return $graph(xy)
     } else {
         return {}
     }
 }

 # SaveSeries, CancelSeries --
 #     Callback procedure for the widget
 #
 # Arguments:
 #     None
 #
 # Result:
 #     None
 #
 # Side effects:
 #     The widget is closed
 #
 proc ::Editgraph::SaveSeries {} {
     set ::Editgraph::endedit 1
     destroy .graph
 }

 proc ::Editgraph::CancelSeries {} {
     set ::Editgraph::endedit 0
     destroy .graph
 }

 # EditPoint --
 #     Callback procedure for setting the new data point
 #
 # Arguments:
 #     w             Widget
 #     x             X-coordinate of selected point (pixel)
 #     y             Y-coordinate of selected point (pixel)
 #
 # Result:
 #     None
 #
 # Side effects:
 #     The data points are updated and the graph redrawn
 #

 proc ::Editgraph::EditPoint {w x y} {
     variable graph

     foreach {xc yc} [::Plotchart::pixelToCoords $graph(widget) $x $y] {break}

     set xp [expr {int(0.5+($xc-$graph(xmin))/$graph(delx))}]

     if { $xp < 0 } { set xp 0 }
     if { $xp > $graph(number) } { set xp $graph(number) }

     lset graph(xy) [expr {2*$xp+1}] $yc

     #
     # Reset the plotted data
     #
     $graph(widget) delete data
     $graph(plot) plot data "" ""

     #
     # Redraw the data
     #
     foreach {x y} $graph(xy) {
         $graph(plot) plot data $x $y
     }

 }

 # main --
 #     Make it all work

 catch {
     console show
 }
 set xyseries [::Editgraph::editSeries {0 100} {-50 50} 10]

 puts "Series:"
 foreach {x y} $xyseries {
     puts [format "%10.4f %10.4f" $x $y]
 }