B-spline: Difference between revisions

Line 45:

Outputs a graphical representation of a B-spline.

=={{header|Phix}}==

You can run this online [http://phix.x10.mx/p2js/bspline.htm here].

--

-- demo\rosetta\B-spline.exw

-- =========================

--

-- Use +/- to change the order between k = 1 and k = 4.

--

with javascript_semantics

include pGUI.e

include IupGraph.e

constant ctrl_points = {{171, 171}, {185, 111}, {202, 109}, {202, 189}, {328, 160}, {208, 254},

{241, 330}, {164, 252}, { 69, 278}, {139, 208}, { 72, 148}, {168, 172}}

integer k = 2, n

sequence t

function w(integer i, k, x) // B-spline helper function

return iff(t[i+k]!=t[i] ? (x-t[i])/(t[i+k]-t[i]) : 0 )

end function

function b(integer i, k, x) // B-spline function

if k==1 then return iff(t[i]<=x and x<t[i+1] ? 1 : 0) end if

return w(i,k-1,x)*b(i,k-1,x) + (1-w(i+1,k-1,x))*b(i+1,k-1,x)

end function

function b_spline(Ihandle graph)

n = length(ctrl_points)

t = tagset(n+1+k) // use a uniform knot vector, delta = 1

assert(k<=n+1 and k>=1,"k (= %d) cannot be more than %d or less than 1.",{k,n+1})

sequence px = {}, py = {}

for x=t[k] to t[n+1] do

atom sumX = 0,

sumY = 0

for i=1 to n do

atom f = b(i,k,x)

sumX += f*ctrl_points[i][1]

sumY += f*ctrl_points[i][2]

end for

px &= round(sumX)

py &= round(sumY)

end for

integer xtick = 40,

ytick = 40,

xmin = trunc(min(px)/xtick)*xtick,

xmax = ceil(max(px)/xtick)*xtick,

ymin = trunc(min(py)/ytick)*ytick,

ymax = ceil(max(py)/ytick)*ytick

IupSetInt(graph,"XTICK",xtick)

IupSetInt(graph,"XMIN",xmin)

IupSetInt(graph,"XMAX",xmax)

IupSetInt(graph,"YTICK",ytick)

IupSetInt(graph,"YMIN",ymin)

IupSetInt(graph,"YMAX",ymax)

sequence graphdata = {{px,py,CD_BLUE}}

return graphdata

end function

procedure set_title(Ihandle dlg)

IupSetStrAttribute(dlg, "TITLE", "B-spline curve (order k = %d)",{k})

end procedure

function key_cb(Ihandle dlg, atom c)

if c=K_ESC then return IUP_CLOSE end if

if c='+' then k = min(k+1,4) end if

if c='-' then k = max(k-1,1) end if

set_title(dlg)

IupRedraw(dlg)

return IUP_IGNORE

end function

procedure main()

IupOpen()

Ihandle graph = IupGraph(b_spline,`RASTERSIZE=600x600`)

Ihandle dlg = IupDialog(graph)

IupSetCallback(dlg, "KEY_CB", Icallback("key_cb"))

set_title(dlg)

IupShow(dlg)

if platform()!=JS then

IupMainLoop()

IupClose()

end if

end procedure

main()

=={{header|Wren}}==

@@ Line 45: / Line 45: @@
 {{out}}
 Outputs a graphical representation of a B-spline.
+=={{header|Phix}}==
+{{trans|Wren}}
+{{libheader|Phix/pGUI}}
+{{libheader|Phix/online}}
+You can run this online [http://phix.x10.mx/p2js/bspline.htm here].
+<!--<lang Phix>(phixonline)-->
+ <span style="color: #000080;font-style:italic;">--
+ -- demo\rosetta\B-spline.exw
+ -- =========================
+ --
+ --  Use +/- to change the order between k = 1 and k = 4.
+ --</span>
+ <span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
+ <span style="color: #008080;">include</span> <span style="color: #000000;">pGUI</span><span style="color: #0000FF;">.</span><span style="color: #000000;">e</span>
+ <span style="color: #008080;">include</span> <span style="color: #000000;">IupGraph</span><span style="color: #0000FF;">.</span><span style="color: #000000;">e</span>
+ <span style="color: #008080;">constant</span> <span style="color: #000000;">ctrl_points</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{{</span><span style="color: #000000;">171</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">171</span><span style="color: #0000FF;">},</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">185</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">111</span><span style="color: #0000FF;">},</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">202</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">109</span><span style="color: #0000FF;">},</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">202</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">189</span><span style="color: #0000FF;">},</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">328</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">160</span><span style="color: #0000FF;">},</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">208</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">254</span><span style="color: #0000FF;">},</span>
+                         <span style="color: #0000FF;">{</span><span style="color: #000000;">241</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">330</span><span style="color: #0000FF;">},</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">164</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">252</span><span style="color: #0000FF;">},</span> <span style="color: #0000FF;">{</span> <span style="color: #000000;">69</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">278</span><span style="color: #0000FF;">},</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">139</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">208</span><span style="color: #0000FF;">},</span> <span style="color: #0000FF;">{</span> <span style="color: #000000;">72</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">148</span><span style="color: #0000FF;">},</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">168</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">172</span><span style="color: #0000FF;">}}</span>
+ <span style="color: #004080;">integer</span> <span style="color: #000000;">k</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">2</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">n</span>
+ <span style="color: #004080;">sequence</span> <span style="color: #000000;">t</span>
+ <span style="color: #008080;">function</span> <span style="color: #000000;">w</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">k</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">)</span>  <span style="color: #000080;font-style:italic;">// B-spline helper function</span>
+     <span style="color: #008080;">return</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">t</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">+</span><span style="color: #000000;">k</span><span style="color: #0000FF;">]!=</span><span style="color: #000000;">t</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">?</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">-</span><span style="color: #000000;">t</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">])/(</span><span style="color: #000000;">t</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">+</span><span style="color: #000000;">k</span><span style="color: #0000FF;">]-</span><span style="color: #000000;">t</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">])</span> <span style="color: #0000FF;">:</span> <span style="color: #000000;">0</span> <span style="color: #0000FF;">)</span>
+ <span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
+ <span style="color: #008080;">function</span> <span style="color: #000000;">b</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">k</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">)</span>  <span style="color: #000080;font-style:italic;">// B-spline function</span>
+     <span style="color: #008080;">if</span> <span style="color: #000000;">k</span><span style="color: #0000FF;">==</span><span style="color: #000000;">1</span> <span style="color: #008080;">then</span> <span style="color: #008080;">return</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">t</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]<=</span><span style="color: #000000;">x</span> <span style="color: #008080;">and</span> <span style="color: #000000;">x</span><span style="color: #0000FF;"><</span><span style="color: #000000;">t</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span> <span style="color: #0000FF;">?</span> <span style="color: #000000;">1</span> <span style="color: #0000FF;">:</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
+     <span style="color: #008080;">return</span> <span style="color: #000000;">w</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">,</span><span style="color: #000000;">k</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">x</span><span style="color: #0000FF;">)*</span><span style="color: #000000;">b</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">,</span><span style="color: #000000;">k</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">x</span><span style="color: #0000FF;">)</span> <span style="color: #0000FF;">+</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">-</span><span style="color: #000000;">w</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">k</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">x</span><span style="color: #0000FF;">))*</span><span style="color: #000000;">b</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">k</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">x</span><span style="color: #0000FF;">)</span>
+ <span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
+ <span style="color: #008080;">function</span> <span style="color: #000000;">b_spline</span><span style="color: #0000FF;">(</span><span style="color: #004080;">Ihandle</span> <span style="color: #000000;">graph</span><span style="color: #0000FF;">)</span>
+     <span style="color: #000000;">n</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">ctrl_points</span><span style="color: #0000FF;">)</span>
+     <span style="color: #000000;">t</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">tagset</span><span style="color: #0000FF;">(</span><span style="color: #000000;">n</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">+</span><span style="color: #000000;">k</span><span style="color: #0000FF;">)</span> <span style="color: #000080;font-style:italic;">// use a uniform knot vector, delta = 1</span>
+     <span style="color: #7060A8;">assert</span><span style="color: #0000FF;">(</span><span style="color: #000000;">k</span><span style="color: #0000FF;"><=</span><span style="color: #000000;">n</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span> <span style="color: #008080;">and</span> <span style="color: #000000;">k</span><span style="color: #0000FF;">>=</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"k (= %d) cannot be more than %d or less than 1."</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">k</span><span style="color: #0000FF;">,</span><span style="color: #000000;">n</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">})</span>
+     <span style="color: #004080;">sequence</span> <span style="color: #000000;">px</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{},</span> <span style="color: #000000;">py</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{}</span>
+     <span style="color: #008080;">for</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">=</span><span style="color: #000000;">t</span><span style="color: #0000FF;">[</span><span style="color: #000000;">k</span><span style="color: #0000FF;">]</span> <span style="color: #008080;">to</span> <span style="color: #000000;">t</span><span style="color: #0000FF;">[</span><span style="color: #000000;">n</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span> <span style="color: #008080;">do</span>
+         <span style="color: #004080;">atom</span> <span style="color: #000000;">sumX</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">,</span>
+              <span style="color: #000000;">sumY</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span>
+         <span style="color: #008080;">for</span> <span style="color: #000000;">i</span><span style="color: #0000FF;">=</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #000000;">n</span> <span style="color: #008080;">do</span>
+             <span style="color: #004080;">atom</span> <span style="color: #000000;">f</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">b</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">,</span><span style="color: #000000;">k</span><span style="color: #0000FF;">,</span><span style="color: #000000;">x</span><span style="color: #0000FF;">)</span>
+             <span style="color: #000000;">sumX</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">f</span><span style="color: #0000FF;">*</span><span style="color: #000000;">ctrl_points</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">][</span><span style="color: #000000;">1</span><span style="color: #0000FF;">]</span>
+             <span style="color: #000000;">sumY</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">f</span><span style="color: #0000FF;">*</span><span style="color: #000000;">ctrl_points</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">][</span><span style="color: #000000;">2</span><span style="color: #0000FF;">]</span>
+         <span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
+         <span style="color: #000000;">px</span> <span style="color: #0000FF;">&=</span> <span style="color: #7060A8;">round</span><span style="color: #0000FF;">(</span><span style="color: #000000;">sumX</span><span style="color: #0000FF;">)</span>
+         <span style="color: #000000;">py</span> <span style="color: #0000FF;">&=</span> <span style="color: #7060A8;">round</span><span style="color: #0000FF;">(</span><span style="color: #000000;">sumY</span><span style="color: #0000FF;">)</span>
+     <span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
+     <span style="color: #004080;">integer</span> <span style="color: #000000;">xtick</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">40</span><span style="color: #0000FF;">,</span>
+             <span style="color: #000000;">ytick</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">40</span><span style="color: #0000FF;">,</span>
+             <span style="color: #000000;">xmin</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">trunc</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">min</span><span style="color: #0000FF;">(</span><span style="color: #000000;">px</span><span style="color: #0000FF;">)/</span><span style="color: #000000;">xtick</span><span style="color: #0000FF;">)*</span><span style="color: #000000;">xtick</span><span style="color: #0000FF;">,</span>
+             <span style="color: #000000;">xmax</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">ceil</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">max</span><span style="color: #0000FF;">(</span><span style="color: #000000;">px</span><span style="color: #0000FF;">)/</span><span style="color: #000000;">xtick</span><span style="color: #0000FF;">)*</span><span style="color: #000000;">xtick</span><span style="color: #0000FF;">,</span>
+             <span style="color: #000000;">ymin</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">trunc</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">min</span><span style="color: #0000FF;">(</span><span style="color: #000000;">py</span><span style="color: #0000FF;">)/</span><span style="color: #000000;">ytick</span><span style="color: #0000FF;">)*</span><span style="color: #000000;">ytick</span><span style="color: #0000FF;">,</span>
+             <span style="color: #000000;">ymax</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">ceil</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">max</span><span style="color: #0000FF;">(</span><span style="color: #000000;">py</span><span style="color: #0000FF;">)/</span><span style="color: #000000;">ytick</span><span style="color: #0000FF;">)*</span><span style="color: #000000;">ytick</span>
+     <span style="color: #7060A8;">IupSetInt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">graph</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"XTICK"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">xtick</span><span style="color: #0000FF;">)</span>
+     <span style="color: #7060A8;">IupSetInt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">graph</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"XMIN"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">xmin</span><span style="color: #0000FF;">)</span>
+     <span style="color: #7060A8;">IupSetInt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">graph</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"XMAX"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">xmax</span><span style="color: #0000FF;">)</span>
+     <span style="color: #7060A8;">IupSetInt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">graph</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"YTICK"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">ytick</span><span style="color: #0000FF;">)</span>
+     <span style="color: #7060A8;">IupSetInt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">graph</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"YMIN"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">ymin</span><span style="color: #0000FF;">)</span>
+     <span style="color: #7060A8;">IupSetInt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">graph</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"YMAX"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">ymax</span><span style="color: #0000FF;">)</span>
+     <span style="color: #004080;">sequence</span> <span style="color: #000000;">graphdata</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{{</span><span style="color: #000000;">px</span><span style="color: #0000FF;">,</span><span style="color: #000000;">py</span><span style="color: #0000FF;">,</span><span style="color: #004600;">CD_BLUE</span><span style="color: #0000FF;">}}</span>
+     <span style="color: #008080;">return</span> <span style="color: #000000;">graphdata</span>
+ <span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
+ <span style="color: #008080;">procedure</span> <span style="color: #000000;">set_title</span><span style="color: #0000FF;">(</span><span style="color: #004080;">Ihandle</span> <span style="color: #000000;">dlg</span><span style="color: #0000FF;">)</span>
+     <span style="color: #7060A8;">IupSetStrAttribute</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dlg</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"TITLE"</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"B-spline curve (order k = %d)"</span><span style="color: #0000FF;">,{</span><span style="color: #000000;">k</span><span style="color: #0000FF;">})</span>
+ <span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
+ <span style="color: #008080;">function</span> <span style="color: #000000;">key_cb</span><span style="color: #0000FF;">(</span><span style="color: #004080;">Ihandle</span> <span style="color: #000000;">dlg</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">atom</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">)</span>
+     <span style="color: #008080;">if</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">=</span><span style="color: #004600;">K_ESC</span> <span style="color: #008080;">then</span> <span style="color: #008080;">return</span> <span style="color: #004600;">IUP_CLOSE</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
+     <span style="color: #008080;">if</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">=</span><span style="color: #008000;">'+'</span> <span style="color: #008080;">then</span> <span style="color: #000000;">k</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">min</span><span style="color: #0000FF;">(</span><span style="color: #000000;">k</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">4</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
+     <span style="color: #008080;">if</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">=</span><span style="color: #008000;">'-'</span> <span style="color: #008080;">then</span> <span style="color: #000000;">k</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">max</span><span style="color: #0000FF;">(</span><span style="color: #000000;">k</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">1</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
+     <span style="color: #000000;">set_title</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dlg</span><span style="color: #0000FF;">)</span>
+     <span style="color: #7060A8;">IupRedraw</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dlg</span><span style="color: #0000FF;">)</span>
+     <span style="color: #008080;">return</span> <span style="color: #004600;">IUP_IGNORE</span>
+ <span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
+ <span style="color: #008080;">procedure</span> <span style="color: #000000;">main</span><span style="color: #0000FF;">()</span>
+     <span style="color: #7060A8;">IupOpen</span><span style="color: #0000FF;">()</span>
+     <span style="color: #004080;">Ihandle</span> <span style="color: #000000;">graph</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">IupGraph</span><span style="color: #0000FF;">(</span><span style="color: #000000;">b_spline</span><span style="color: #0000FF;">,</span><span style="color: #008000;">`RASTERSIZE=600x600`</span><span style="color: #0000FF;">)</span>
+     <span style="color: #004080;">Ihandle</span> <span style="color: #000000;">dlg</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">IupDialog</span><span style="color: #0000FF;">(</span><span style="color: #000000;">graph</span><span style="color: #0000FF;">)</span>
+     <span style="color: #7060A8;">IupSetCallback</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dlg</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"KEY_CB"</span><span style="color: #0000FF;">,</span> <span style="color: #7060A8;">Icallback</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"key_cb"</span><span style="color: #0000FF;">))</span>
+     <span style="color: #000000;">set_title</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dlg</span><span style="color: #0000FF;">)</span>
+     <span style="color: #7060A8;">IupShow</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dlg</span><span style="color: #0000FF;">)</span>
+     <span style="color: #008080;">if</span> <span style="color: #7060A8;">platform</span><span style="color: #0000FF;">()!=</span><span style="color: #004600;">JS</span> <span style="color: #008080;">then</span>
+         <span style="color: #7060A8;">IupMainLoop</span><span style="color: #0000FF;">()</span>
+         <span style="color: #7060A8;">IupClose</span><span style="color: #0000FF;">()</span>
+     <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
+ <span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
+ <span style="color: #000000;">main</span><span style="color: #0000FF;">()</span>
+<!--</lang>-->
 =={{header|Wren}}==