timeliner
Richard Suchenwirth 2004-08-10 - Yet another thing to do with a canvas: history visualisation of a horizontal time-line, for which a year scale is displayed on top. The following kinds of objects are so far available:
- "eras", displayed in yellow below the timeline in boxes
- "background items" that are grey and stretch over all the canvas in height
- normal items, which get displayed as stacked orange bars
You can zoom in with <1>, out with <3> (both only in x direction). On mouse motion, the current year is displayed in the toplevel's title. Normal items can be a single year, like the Columbus example, or a range of years, for instance for lifetimes of persons. (The example shows that Mozart didn't live long...)
namespace eval timeliner {
variable ""
array set "" {-zoom 1 -from 0 -to 2000}
}
proc timeliner::create {w args} {
variable ""
array set "" $args
#-- draw time scale
for {set x [expr ($(-from)/50)*50]} {$x<=$(-to)} {incr x 10} {
if {$x%50 == 0} {
$w create line $x 8 $x 0
$w create text $x 8 -text $x -anchor n
} else {
$w create line $x 5 $x 0
}
}
# bind $w <Motion> {wm title . [expr int([%W canvasx %x]/$::timeliner::(-zoom))]}
bind $w <Motion> {timeliner::title %W %x ; timeliner::movehair %W %x}
bind $w <1> {timeliner::zoom %W %x 1.25}
bind $w <2> {timeliner::hair %W %x}
bind $w <3> {timeliner::zoom %W %x 0.8}
}
proc timeliner::movehair {w x} {
variable ""
if {[llength [$w find withtag hair]]} {
set x [$w canvasx $x]
$w move hair [expr {$x - $(x)}] 0
set (x) $x
}
}
proc timeliner::hair {w x} {
variable ""
if {[llength [$w find withtag hair]]} {
$w delete hair
} else {
set (x) [$w canvasx $x]
$w create line $(x) 0 $(x) [$w cget -height] \
-tags hair -width 1 -fill red
}
}
proc timeliner::title {w x} {
variable ""
wm title . [expr int([$w canvasx $x]/$(-zoom))]
}
proc timeliner::zoom {w x factor} {
variable ""
$w scale all 0 0 $factor 1
set (-zoom) [expr {$(-zoom)*$factor}]
$w config -scrollregion [$w bbox all]
if {[llength [$w find withtag hair]]} {
$w delete hair
set (x) [$w canvasx $x]
$w create line $(x) 0 $(x) [$w cget -height] \
-tags hair -width 1 -fill red
}
}This command adds an object to the canvas. The code for "item" took me some effort, as it had to locate a free "slot" on the canvas, searching top-down:
proc timeliner::add {w type name time args} {
variable ""
regexp {(\d+)(-(\d+))?} $time -> from - to
if {$to eq ""} {set to $from}
set x0 [expr {$from*$(-zoom)}]
set x1 [expr {$to*$(-zoom)}]
switch -- $type {
era {set fill yellow; set outline black; set y0 20; set y1 40}
bgitem {set fill gray; set outline {}; set y0 40; set y1 1024}
item {
set fill orange
set outline yellow
for {set y0 60} {$y0<400} {incr y0 20} {
set y1 [expr {$y0+18}]
if {[$w find overlap [expr $x0-5] $y0 $x1 $y1] eq ""} break
}
}
}
set id [$w create rect $x0 $y0 $x1 $y1 -fill $fill -outline $outline]
if {$type eq "bgitem"} {$w lower $id}
set tid [$w create text [expr {$x0+5}] [expr {$y0+2}] -text $name -anchor nw]
foreach arg $args {
if {$arg eq "!"} {
# modified by buchs $w itemconfig $tid -font "[$w itemcget $tid -font] bold"
# appropriately handles return of TkDefaultFont
set fontused [font actual [$w itemcget $tid -font]]
set fontbold [regsub -- {-weight [^ ]*} $fontused {-weight bold}]
$w itemconfig $tid -font "$fontbold"
}
}
$w config -scrollregion [$w bbox all]
}Here's a sample application, featuring a concise history of music in terms of composers:
scrollbar .x -ori hori -command {.c xview}
pack .x -side bottom -fill x
canvas .c -bg white -width 600 -height 300 -xscrollcommand {.x set}
pack .c -fill both -expand 1
timeliner::create .c -from 1400 -to 2000These nifty shorthands for adding items make data specification a breeze - compare the original call, and the shorthand:
timeliner::add .c item Purcell 1659-1695
- Purcell 1659-1695With an additional "!" argument you can make the text of an item bold:
foreach {shorthand type} {* era x bgitem - item} {
interp alias {} $shorthand {} timeliner::add .c $type
}
#-- Now for the data to display (written pretty readably):
* {Middle Ages} 1400-1450
- Dufay 1400-1474
* Renaissance 1450-1600
- Desprez 1440-1521
- Luther 1483-1546
- {Columbus discovers America} 1492
- Palestrina 1525-1594 !
- Lasso 1532-1594
- Byrd 1543-1623
* Baroque 1600-1750
- Dowland 1563-1626
- Monteverdi 1567-1643
- Schütz 1585-1672
- Purcell 1659-1695
- Telemann 1681-1767
- Rameau 1683-1764
- Bach,J.S. 1685-1750 !
- Händel 1685-1759
x {30-years war} 1618-1648
* {Classic era} 1750-1810
- Haydn 1732-1809 !
- Boccherini 1743-1805
- Mozart 1756-1791 !
- Beethoven 1770-1828 !
* {Romantic era} 1810-1914
- {Mendelssohn Bartholdy} 1809-1847
- Chopin 1810-1849
- Liszt 1811-1886
- Verdi 1813-1901
x {French revolution} 1789-1800
* {Modern era} 1914-2000
- Ravel 1875-1937 !
- Bartók 1881-1945
- Stravinskij 1882-1971
- Varèse 1883-1965
- Prokof'ev 1891-1953
- Milhaud 1892-1974
- Honegger 1892-1955
- Hindemith 1895-1963
- Britten 1913-1976
x WW1 1914-1918
x WW2 1938-1945
bind . <Escape> {exec wish $argv0 &; exit}
bind . <F1> {console show}US Nice. I took the freedom to add a red hair. Toggle on/off with middle button.
escargo - Note that not all user interfaces will provide three mouse buttons, like the laptop I'm using right now.
RS: Thanks for your interest and comments. Testing the hair, I find that my mouse has a middle button, but Tk seems not to respond to it :( I noted however that someone changed references to the "anonymous array" "" into the namespace path ::timeliner:: . That is redundant and less convenient, should the name of the namespace change. So I changed back references like
$::timeliner::(-zoom)
to the equivalent (as long as we're in the ::timeliner namespace)
$(-zoom)
That's why I declare variable "", and that's what the anonymous array was created for - beautiful minimal syntax ... :)
Sep-4-2004 JM If you want to map events in minutes (like activities in a working day) you can see this very same code, with just a few lines modified timeliner (minutes instead of years)
AMG: Somebody munged the encoding, so I fixed it back using [encoding convertfrom utf-8]. Please be careful when editing pages.
Jan-28-2009 buchs: I added some code to the bolding section, to enable handling a return of TkDefaultFont.