JM The following examples show the basic usage of the BLT charting capabilities.
As many of the BLT users will notice, these examples just show the tip of the iceberg, but sometimes we are looking for the minimal example for a quick startup...
Example 1: Barchart Basic Usage
package require BLT
blt::barchart .g -title "Comparison"
pack .g
.g element create BT1 -xdata {1 2 3 4 5 6 7 8} -ydata {.76 .98 .88 .92 .96 .98 .91 .80} -label {Series 1}\
-showvalues yExample 2: Barchart Showing 2 series of data
package require BLT
blt::barchart .g -title "Comparison" -barmode aligned
pack .g
.g element create BT1 -xdata {1 2 3 4 5 6 7 8} -ydata {.76 .98 .88 .92 .96 .98 .91 .80} -label {Series 1}\
-showvalues y
.g element create BT2 -xdata {1 2 3 4 5 6 7 8} -ydata {.1 .2 .3 .4 .5 .6 .7 .8} -label {Series 2}\
-showvalues y -foreground redExample 3: UK Function plotting using vector expr ...
#!/usr/bin/wish
package require BLT
namespace import ::blt::*
proc compute args {
catch {
::y expr { \
($::a * (::x ^ 3) ) + ($::b * (::x ^ 2) ) \
+ ($::c * ::x) + $::d \
}
} cerr
}
label .l -text "Function: ax^3 + bx^2 + cx + d" ; table . .l 0,0
graph .g -width 700 -height 600 -bd 2 -relief groove ; table . .g 1,0 -fill both
vector ::x ; ::x seq -10 10 0.5
vector ::y
set items {label variable to from digits resolution tickinterval gridpos}
set scale_cfg {
a ::a -0.31 0.3 5 0.001 0.1 1,1
b ::b -1.01 1.0 5 0.002 0.5 1,2
c ::c -4.01 4.0 4 0.01 2.0 1,3
d ::d -10.01 10.0 3 0.1 5.0 1,4
}
foreach $items $scale_cfg {
set $variable 0.0
trace variable $variable w compute
set w .sc$label
set label [ string totitle $label ]
scale $w -label $label \
-variable $variable -to $to -from $from \
-digits $digits -resolution $resolution \
-tickinterval $tickinterval \
-bd 2 -relief groove
table . $w $gridpos -fill y
}
# fill vector ::y
compute
.g element create Function -xdata ::x -ydata ::y -pixels 3
.g axis configure y -min -20 -max 20
.g grid configure -hide no -dashes { 2 2 }
# ready#JM very nice.