In order to represent evolutions of contents over time, the [http://www.w3.org/TR/SMIL/ SMIL] standard provides a solution to record the animation of data. Smil animations can be added to any kind of contents formated in XML.
- [[wp:Synchronized_Multimedia_Integration_Language|SMIL on Wikipedia]] and [http://www.w3.org/TR/SMIL/smil-animation.html#q35 at W3]
The task is to create an utility that given the first Smiled XML file, would return the following ones:
<?xml version="1.0" ?>
<smil>
<X3D>
<Scene>
<Viewpoint position="0 0 8" orientation="0 0 1 0"/>
<PointLight color='1 1 1' location='0 2 0'/>
<Shape>
<Box size='2 1 2'>
<animate attributeName="size" from="2 1 2"
to="1 2 1" begin="0s" dur="10s"/>
</Box>
<Appearance>
<Material diffuseColor='0.0 0.6 1.0'>
<animate attributeName="diffuseColor" from="0.0 0.6 1.0"
to="1.0 0.4 0.0" begin="0s" dur="10s"/>
</Material>
</Appearance>
</Shape>
</Scene>
</X3D>
</smil>
At t = 0 second here is the expected output:
<?xml version="1.0" ?>
<X3D>
<Scene>
<Viewpoint position="0 0 8" orientation="0 0 1 0"/>
<PointLight color='1 1 1' location='0 2 0'/>
<Shape>
<Box size='2 1 2'/>
<Appearance>
<Material diffuseColor='0.0 0.6 1.0'/>
</Appearance>
</Shape>
</Scene>
</X3D>
At t = 2 second here is the expected output:
<?xml version="1.0" ?>
<X3D>
<Scene>
<Viewpoint position="0 0 8" orientation="0 0 1 0"/>
<PointLight color='1 1 1' location='0 2 0'/>
<Shape>
<Box size='1.8 1.2 1.8'/>
<Appearance>
<Material diffuseColor='0.2 0.56 0.8'/>
</Appearance>
</Shape>
</Scene>
</X3D>
Go
package main
import (
"fmt"
"github.com/beevik/etree"
"log"
"os"
"strconv"
"strings"
)
type animData struct {
element *etree.Element
attrib string
from string
to string
begin float64
dur float64
}
func check(err error) {
if err != nil {
log.Fatal(err)
}
}
func (ad *animData) AtTime(t float64) string {
beg := ad.begin
end := beg + ad.dur
if t < beg || t > end {
log.Fatalf("time must be in interval [%g, %g]", beg, end)
}
fromSplit := strings.Fields(ad.from)
toSplit := strings.Fields(ad.to)
le := len(fromSplit)
interSplit := make([]string, le)
for i := 0; i < le; i++ {
fromF, err := strconv.ParseFloat(fromSplit[i], 64)
check(err)
toF, err := strconv.ParseFloat(toSplit[i], 64)
check(err)
interF := (fromF*(end-t) + toF*(t-beg)) / ad.dur
interSplit[i] = fmt.Sprintf("%.2f", interF)
}
return strings.Join(interSplit, " ")
}
func main() {
doc := etree.NewDocument()
check(doc.ReadFromFile("smil.xml"))
smil := doc.SelectElement("smil")
if smil == nil {
log.Fatal("'smil' element not found")
}
x3d := smil.SelectElement("X3D")
if x3d == nil {
log.Fatal("'X3D' element not found")
}
doc.SetRoot(x3d) // remove 'smil' element
var ads []*animData
for _, a := range doc.FindElements("//animate") {
attrib := a.SelectAttrValue("attributeName", "?")
from := a.SelectAttrValue("from", "?")
to := a.SelectAttrValue("to", "?")
beginS := a.SelectAttrValue("begin", "?")
durS := a.SelectAttrValue("dur", "?")
if attrib == "?" || from == "?" || to == "?" ||
beginS == "?" || durS == "?" {
log.Fatal("an animate element has missing attribute(s)")
}
begin, err := strconv.ParseFloat(beginS[:len(beginS)-1], 64)
check(err)
dur, err := strconv.ParseFloat(durS[:len(durS)-1], 64)
check(err)
p := a.Parent()
if p == nil {
log.Fatal("an animate element has no parent")
}
pattrib := p.SelectAttrValue(attrib, "?")
if pattrib == "?" {
log.Fatal("an animate element's parent has missing attribute")
}
ads = append(ads, &animData{p, attrib, from, to, begin, dur})
p.RemoveChild(a) // remove 'animate' element
}
ts := []float64{0, 2}
for _, t := range ts {
for _, ad := range ads {
s := ad.AtTime(t)
ad.element.CreateAttr(ad.attrib, s)
}
doc.Indent(2)
fmt.Printf("At time = %g seconds:\n\n", t)
doc.WriteTo(os.Stdout)
fmt.Println()
}
}
At time = 0 seconds:
<?xml version="1.0" ?>
<X3D>
<Scene>
<Viewpoint position="0 0 8" orientation="0 0 1 0"/>
<PointLight color="1 1 1" location="0 2 0"/>
<Shape>
<Box size="2.00 1.00 2.00"/>
<Appearance>
<Material diffuseColor="0.00 0.60 1.00"/>
</Appearance>
</Shape>
</Scene>
</X3D>
At time = 2 seconds:
<?xml version="1.0" ?>
<X3D>
<Scene>
<Viewpoint position="0 0 8" orientation="0 0 1 0"/>
<PointLight color="1 1 1" location="0 2 0"/>
<Shape>
<Box size="1.80 1.20 1.80"/>
<Appearance>
<Material diffuseColor="0.20 0.56 0.80"/>
</Appearance>
</Shape>
</Scene>
</X3D>
Phix
include builtins\xml.e
constant xml = """
<?xml version="1.0" ?>
<smil>
<X3D>
<Scene>
<Viewpoint position="0 0 8" orientation="0 0 1 0"/>
<PointLight color='1 1 1' location='0 2 0'/>
<Shape>
<Box size='2 1 2'>
<animate attributeName="size" from="2 1 2"
to="1 2 1" begin="0s" dur="10s"/>
</Box>
<Appearance>
<Material diffuseColor='0.0 0.6 1.0'>
<animate attributeName="diffuseColor" from="0.0 0.6 1.0"
to="1.0 0.4 0.0" begin="0s" dur="10s"/>
</Material>
</Appearance>
</Shape>
</Scene>
</X3D>
</smil>
"""
function scan_all(sequence s, fmt)
for i=1 to length(s) do
{{s[i]}} = scanf(s[i],fmt)
end for
return s
end function
function animate_contents(sequence doc, atom t)
sequence a = xml_get_nodes(doc,"animate")
if a={} then
for i=1 to length(doc[XML_CONTENTS]) do
doc[XML_CONTENTS][i] = animate_contents(doc[XML_CONTENTS][i],t)
end for
else
for i=1 to length(doc[XML_CONTENTS]) do
if doc[XML_CONTENTS][i][XML_TAGNAME]="animate" then
string name = xml_get_attribute(doc[XML_CONTENTS][i],"attributeName"),
vfrm = xml_get_attribute(doc[XML_CONTENTS][i],"from"),
v_to = xml_get_attribute(doc[XML_CONTENTS][i],"to"),
sbeg = xml_get_attribute(doc[XML_CONTENTS][i],"begin"),
sdur = xml_get_attribute(doc[XML_CONTENTS][i],"dur")
sequence from = scan_all(split(vfrm),"%f"),
to_s = scan_all(split(v_to),"%f")
atom {{begin}} = scanf(sbeg,"%fs"),
{{durat}} = scanf(sdur,"%fs"),
fj = begin+durat-t,
tj = t-begin
-- plenty more error handling possible here...
if tj<0 or fj<0 or length(from)!=length(to_s) then ?9/0 end if
for j=1 to length(from) do
from[j] = sprintf("%.2f",(from[j]*fj+to_s[j]*tj)/durat)
end for
doc = xml_set_attribute(doc,name,join(from," "))
doc[XML_CONTENTS][i..i] = "" -- remove 'animate'
exit
end if
end for
end if
return doc
end function
function animate(sequence doc, atom t)
doc[XML_CONTENTS] = doc[XML_CONTENTS][XML_CONTENTS][1] -- remove smil
doc[XML_CONTENTS] = animate_contents(doc[XML_CONTENTS],t)
return doc
end function
sequence doc = xml_parse(xml)
if doc[XML_DOCUMENT]!="document"
or doc[XML_CONTENTS][XML_TAGNAME]!="smil"
or length(doc[XML_CONTENTS][XML_CONTENTS])!=1
or doc[XML_CONTENTS][XML_CONTENTS][1][XML_TAGNAME]!="X3D" then
?9/0
end if
printf(1,"At time = 0:\n\n")
puts(1,xml_sprint(animate(doc,0)))
printf(1,"\nAt time = 2:\n\n")
puts(1,xml_sprint(animate(doc,2)))
At time = 0:
<?xml version="1.0" ?>
<X3D>
<Scene>
<Viewpoint position="0 0 8" orientation="0 0 1 0" />
<PointLight color="1 1 1" location="0 2 0" />
<Shape>
<Box size="2.00 1.00 2.00" />
<Appearance>
<Material diffuseColor="0.00 0.60 1.00" />
</Appearance>
</Shape>
</Scene>
</X3D>
At time = 2:
<?xml version="1.0" ?>
<X3D>
<Scene>
<Viewpoint position="0 0 8" orientation="0 0 1 0" />
<PointLight color="1 1 1" location="0 2 0" />
<Shape>
<Box size="1.80 1.20 1.80" />
<Appearance>
<Material diffuseColor="0.20 0.56 0.80" />
</Appearance>
</Shape>
</Scene>
</X3D>
Tcl
package require Tcl 8.6
package require tdom
# Applies a time-based interpolation to generate a space-separated list
proc interpolate {time info} {
dict with info {
scan $begin "%fs" begin
scan $dur "%fs" dur
}
if {$time < $begin} {
return $from
} elseif {$time > $begin+$dur} {
return $to
}
set delta [expr {($time - $begin) / $dur}]
return [lmap f $from t $to {expr {$f + ($t-$f)*$delta}}]
}
# Applies SMIL <transform> elements to their container
proc applySMILtransform {sourceDocument time} {
set doc [dom parse [$sourceDocument asXML]]
foreach smil [$doc selectNodes //smil] {
foreach context [$smil selectNodes {//*[animate]}] {
set animator [$context selectNodes animate]
set animated [$context selectNodes @[$animator @attributeName]]
$context removeChild $animator
$context setAttribute [$animator @attributeName] \
[interpolate $time [lindex [$animator asList] 1]]
}
if {[$smil parentNode] eq ""} {
set reparent 1
} else {
[$smil parentNode] replaceChild $smil [$smil firstChild]
}
}
if {[info exist reparent]} {
set doc [dom parse [[$smil firstChild] asXML]]
}
return $doc
}
set t [expr {[lindex $argv 0] + 0.0}]
set result [applySMILtransform [dom parse [read stdin]] $t]
puts {<?xml version="1.0" ?>}
puts -nonewline [$result asXML -indent 2]
Note that input.smil contains the source document from the task description.
$ tclsh8.6 applySmil.tcl 0 < input.smil
<?xml version="1.0" ?>
<X3D>
<Scene>
<Viewpoint position="0 0 8" orientation="0 0 1 0"/>
<PointLight color="1 1 1" location="0 2 0"/>
<Shape>
<Box size="2.0 1.0 2.0"/>
<Appearance>
<Material diffuseColor="0.0 0.6 1.0"/>
</Appearance>
</Shape>
</Scene>
</X3D>
$ tclsh8.6 applySmil.tcl 2 < input.smil
<?xml version="1.0" ?>
<X3D>
<Scene>
<Viewpoint position="0 0 8" orientation="0 0 1 0"/>
<PointLight color="1 1 1" location="0 2 0"/>
<Shape>
<Box size="1.8 1.2 1.8"/>
<Appearance>
<Material diffuseColor="0.2 0.5599999999999999 0.8"/>
</Appearance>
</Shape>
</Scene>
</X3D>