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Xiaolin Wu's line algorithm: Difference between revisions

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Xiaolin Wu's line algorithm (view source)

Revision as of 16:23, 21 April 2022

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=={{header|Phix}}==
For educational/comparison purposes only: see demo\pGUI\aaline.exw for a much shorter version.<br>
Resize the window to show lines at any angle
{{libheader|Phix/pGUI}}
{{libheader|Phix/online}}
<lang Phix>-- demo\rosetta\XiaolinWuLine.exw
You can run this online [http://phix.x10.mx/p2js/wuline.htm here].
constant TITLE = "Xiaolin Wu's line algorithm"
Resize the window to show lines at any angle
 
<!--<lang Phix>(phixonline)-->
bool bresline = false -- space toggles, for comparison
<span style="color: #000080;font-style:italic;">--
 
-- demo\rosetta\XiaolinWuLine.exw
include pGUI.e
-- ==============================
 
--
Ihandle dlg, canvas
-- Resize the window to show lines at any angle
cdCanvas cddbuffer, cdcanvas
--
 
-- For education/comparision purposes only: see demo\pGUI\aaline.exw
constant BACK = CD_PARCHMENT,
-- for a much shorter version, but "wrong algorithm" for the RC task.
LINE = CD_BLUE,
-- Also note this blends with BACK rather than the actual pixel,
rB = red(BACK), gB = green(BACK), bB = blue(BACK),
-- whereas aaline.exw does it properly.
rL = red(LINE), gL = green(LINE), bL = blue(LINE)
--</span>
 
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span> <span style="color: #000080;font-style:italic;">-- not really fair: pwa/p2js uses OpenGL
procedure plot(atom x, atom y, atom c, bool steep=false)
-- and does not draw bresenham lines anyway/ever, plus the next line
-- plot the pixel at (x, y) with brightness c (where 0 <= c <= 1)
-- makes no difference whatsoever when running this in a browser.</span>
if steep then {x,y} = {y,x} end if
<span style="color: #008080;">constant</span> <span style="color: #000000;">USE_OPENGL</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span>
atom C = 1-c
c = rgb(rL*c+rB*C,gL*c+gB*C,bL*c+bB*C)
<span style="color: #008080;">constant</span> <span style="color: #000000;">TITLE</span> <span style="color: #0000FF;">=</span> <span style="color: #008000;">"Xiaolin Wu's line algorithm"</span>
cdCanvasPixel(cddbuffer, x, y, c)
end procedure
<span style="color: #008080;">include</span> <span style="color: #000000;">pGUI</span><span style="color: #0000FF;">.</span><span style="color: #000000;">e</span>
 
procedure plot2(atom x, atom y, atom f, atom xgap, bool steep)
<span style="color: #004080;">Ihandle</span> <span style="color: #000000;">dlg</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">canvas</span>
plot(x,y,(1-f)*xgap,steep)
<span style="color: #004080;">cdCanvas</span> <span style="color: #000000;">cddbuffer</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">cdcanvas</span>
plot(x,y+1,f*xgap,steep)
end procedure
<span style="color: #004080;">bool</span> <span style="color: #000000;">wuline</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">true</span> <span style="color: #000080;font-style:italic;">-- space toggles, for comparison
 
-- when false, and with USE_OPENGL, lines are still smooth,
function fpart(atom x)
-- but a bit thicker - and therefore less "ropey".
return x - floor(x) -- fractional part of x
-- when false, but without USE_OPENGL, it draws bresenham
end function
-- lines (ie jagged, without anti-aliasing [desktop only]).</span>
 
procedure draw_line(atom x0,y0,x1,y1)
<span style="color: #004080;">integer</span> <span style="color: #000000;">BACK</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">CD_PARCHMENT</span><span style="color: #0000FF;">,</span>
if bresline then
<span style="color: #000000;">LINE</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">CD_BLUE</span><span style="color: #0000FF;">,</span>
cdCanvasLine(cddbuffer, x0, y0, x1, y1)
<span style="color: #0000FF;">{</span><span style="color: #000000;">rB</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">gB</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">bB</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">to_rgb</span><span style="color: #0000FF;">(</span><span style="color: #000000;">BACK</span><span style="color: #0000FF;">),</span>
return
<span style="color: #0000FF;">{</span><span style="color: #000000;">rL</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">gL</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">bL</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">to_rgb</span><span style="color: #0000FF;">(</span><span style="color: #000000;">LINE</span><span style="color: #0000FF;">)</span>
end if
bool steep := abs(y1 - y0) > abs(x1 - x0)
<span style="color: #008080;">procedure</span> <span style="color: #000000;">plot</span><span style="color: #0000FF;">(</span><span style="color: #004080;">atom</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">bool</span> <span style="color: #000000;">steep</span><span style="color: #0000FF;">=</span><span style="color: #004600;">false</span><span style="color: #0000FF;">)</span>
if steep then
<span style="color: #000080;font-style:italic;">-- plot the pixel at (x, y) with brightness c (where 0 &lt;= c &lt;= 1)</span>
{x0, y0, x1, y1} = {y0, x0, y1, x1}
<span style="color: #008080;">if</span> <span style="color: #000000;">steep</span> <span style="color: #008080;">then</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">x</span><span style="color: #0000FF;">,</span><span style="color: #000000;">y</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">y</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;">if</span>
end if
<span style="color: #004080;">atom</span> <span style="color: #000000;">C</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">1</span><span style="color: #0000FF;">-</span><span style="color: #000000;">c</span>
if x0>x1 then
<span style="color: #000000;">c</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">rgb</span><span style="color: #0000FF;">(</span><span style="color: #000000;">rL</span><span style="color: #0000FF;">*</span><span style="color: #000000;">c</span><span style="color: #0000FF;">+</span><span style="color: #000000;">rB</span><span style="color: #0000FF;">*</span><span style="color: #000000;">C</span><span style="color: #0000FF;">,</span><span style="color: #000000;">gL</span><span style="color: #0000FF;">*</span><span style="color: #000000;">c</span><span style="color: #0000FF;">+</span><span style="color: #000000;">gB</span><span style="color: #0000FF;">*</span><span style="color: #000000;">C</span><span style="color: #0000FF;">,</span><span style="color: #000000;">bL</span><span style="color: #0000FF;">*</span><span style="color: #000000;">c</span><span style="color: #0000FF;">+</span><span style="color: #000000;">bB</span><span style="color: #0000FF;">*</span><span style="color: #000000;">C</span><span style="color: #0000FF;">)</span>
{x0, x1, y0, y1} = {x1, x0, y1, y0}
<span style="color: #7060A8;">cdCanvasPixel</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cddbuffer</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">c</span><span style="color: #0000FF;">)</span>
end if
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
atom dx := x1 - x0,
<span style="color: #008080;">procedure</span> <span style="color: #000000;">plot2</span><span style="color: #0000FF;">(</span><span style="color: #004080;">atom</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">f</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">xgap</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">bool</span> <span style="color: #000000;">steep</span><span style="color: #0000FF;">)</span>
dy := y1 - y0,
<span style="color: #000000;">plot</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">,</span><span style="color: #000000;">y</span><span style="color: #0000FF;">,(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">-</span><span style="color: #000000;">f</span><span style="color: #0000FF;">)*</span><span style="color: #000000;">xgap</span><span style="color: #0000FF;">,</span><span style="color: #000000;">steep</span><span style="color: #0000FF;">)</span>
gradient := iff(dx=0? 1 : dy / dx)
<span style="color: #000000;">plot</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">,</span><span style="color: #000000;">y</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,(</span><span style="color: #000000;">f</span><span style="color: #0000FF;">)*</span><span style="color: #000000;">xgap</span><span style="color: #0000FF;">,</span><span style="color: #000000;">steep</span><span style="color: #0000FF;">)</span>
 
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
-- handle first endpoint
atom xend := round(x0),
<span style="color: #008080;">function</span> <span style="color: #000000;">fpart</span><span style="color: #0000FF;">(</span><span style="color: #004080;">atom</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">)</span>
yend := y0 + gradient * (xend - x0),
<span style="color: #008080;">return</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">-</span><span style="color: #7060A8;">floor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">)</span> <span style="color: #000080;font-style:italic;">-- fractional part of x</span>
xgap := 1-fpart(x0 + 0.5),
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
xpxl1 := xend, -- this will be used in the main loop
ypxl1 := floor(yend)
<span style="color: #008080;">procedure</span> <span style="color: #000000;">wu_line</span><span style="color: #0000FF;">(</span><span style="color: #004080;">atom</span> <span style="color: #000000;">x0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">y0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">x1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">y1</span><span style="color: #0000FF;">)</span>
plot2(xpxl1, ypxl1, fpart(yend), xgap, steep)
<span style="color: #004080;">bool</span> <span style="color: #000000;">steep</span> <span style="color: #0000FF;">:=</span> <span style="color: #7060A8;">abs</span><span style="color: #0000FF;">(</span><span style="color: #000000;">y1</span> <span style="color: #0000FF;">-</span> <span style="color: #000000;">y0</span><span style="color: #0000FF;">)</span> <span style="color: #0000FF;">></span> <span style="color: #7060A8;">abs</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x1</span> <span style="color: #0000FF;">-</span> <span style="color: #000000;">x0</span><span style="color: #0000FF;">)</span>
atom intery := yend + gradient -- first y-intersection for the main loop
<span style="color: #008080;">if</span> <span style="color: #000000;">steep</span> <span style="color: #008080;">then</span>
<span style="color: #0000FF;">{</span><span style="color: #000000;">x0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">x1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y1</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">y0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">x0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">x1</span><span style="color: #0000FF;">}</span>
-- handle second endpoint
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
xend := round(x1)
<span style="color: #008080;">if</span> <span style="color: #000000;">x0</span><span style="color: #0000FF;">></span><span style="color: #000000;">x1</span> <span style="color: #008080;">then</span>
yend := y1 + gradient * (xend - x1)
<span style="color: #0000FF;">{</span><span style="color: #000000;">x0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">x1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y1</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">x1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">x0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y0</span><span style="color: #0000FF;">}</span>
xgap := fpart(x1 + 0.5)
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
atom xpxl2 := xend, -- this will be used in the main loop
ypxl2 := floor(yend)
<span style="color: #004080;">atom</span> <span style="color: #000000;">dx</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">x1</span> <span style="color: #0000FF;">-</span> <span style="color: #000000;">x0</span><span style="color: #0000FF;">,</span>
plot2(xpxl2, ypxl2, fpart(yend), xgap, steep)
<span style="color: #000000;">dy</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">y1</span> <span style="color: #0000FF;">-</span> <span style="color: #000000;">y0</span><span style="color: #0000FF;">,</span>
<span style="color: #000000;">gradient</span> <span style="color: #0000FF;">:=</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dx</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span><span style="color: #0000FF;">?</span> <span style="color: #000000;">1</span> <span style="color: #0000FF;">:</span> <span style="color: #000000;">dy</span> <span style="color: #0000FF;">/</span> <span style="color: #000000;">dx</span><span style="color: #0000FF;">)</span>
-- main loop
for x = xpxl1+1 to xpxl2-1 do
<span style="color: #000080;font-style:italic;">-- handle first endpoint</span>
plot2(x, floor(intery), fpart(intery), 1, steep)
<span style="color: #004080;">atom</span> <span style="color: #000000;">xend</span> <span style="color: #0000FF;">:=</span> <span style="color: #7060A8;">round</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x0</span><span style="color: #0000FF;">),</span>
intery += gradient
<span style="color: #000000;">yend</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">y0</span> <span style="color: #0000FF;">+</span> <span style="color: #000000;">gradient</span> <span style="color: #0000FF;">*</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">xend</span> <span style="color: #0000FF;">-</span> <span style="color: #000000;">x0</span><span style="color: #0000FF;">),</span>
end for
<span style="color: #000000;">xgap</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">1</span> <span style="color: #0000FF;">-</span> <span style="color: #000000;">fpart</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x0</span> <span style="color: #0000FF;">+</span> <span style="color: #000000;">0.5</span><span style="color: #0000FF;">),</span>
end procedure
<span style="color: #000000;">xpxl1</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">xend</span><span style="color: #0000FF;">,</span> <span style="color: #000080;font-style:italic;">-- this will be used in the main loop</span>
 
<span style="color: #000000;">ypxl1</span> <span style="color: #0000FF;">:=</span> <span style="color: #7060A8;">floor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">yend</span><span style="color: #0000FF;">)</span>
function redraw_cb(Ihandle /*ih*/, integer /*posx*/, integer /*posy*/)
<span style="color: #000000;">plot2</span><span style="color: #0000FF;">(</span><span style="color: #000000;">xpxl1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">ypxl1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">fpart</span><span style="color: #0000FF;">(</span><span style="color: #000000;">yend</span><span style="color: #0000FF;">),</span> <span style="color: #000000;">xgap</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">steep</span><span style="color: #0000FF;">)</span>
integer {w, h} = sq_sub(IupGetIntInt(canvas, "DRAWSIZE"),10)
<span style="color: #004080;">atom</span> <span style="color: #000000;">intery</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">yend</span> <span style="color: #0000FF;">+</span> <span style="color: #000000;">gradient</span> <span style="color: #000080;font-style:italic;">-- first y-intersection for the main loop
cdCanvasActivate(cddbuffer)
cdCanvasClear(cddbuffer)
-- handle second endpoint</span>
draw_line(0,0,200,200)
<span style="color: #000000;">xend</span> <span style="color: #0000FF;">:=</span> <span style="color: #7060A8;">round</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x1</span><span style="color: #0000FF;">)</span>
draw_line(w,0,200,200)
<span style="color: #000000;">yend</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">y1</span> <span style="color: #0000FF;">+</span> <span style="color: #000000;">gradient</span> <span style="color: #0000FF;">*</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">xend</span> <span style="color: #0000FF;">-</span> <span style="color: #000000;">x1</span><span style="color: #0000FF;">)</span>
draw_line(0,h,200,200)
<span style="color: #000000;">xgap</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">fpart</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x1</span> <span style="color: #0000FF;">+</span> <span style="color: #000000;">0.5</span><span style="color: #0000FF;">)</span>
draw_line(w,h,200,200)
<span style="color: #004080;">atom</span> <span style="color: #000000;">xpxl2</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">xend</span><span style="color: #0000FF;">,</span> <span style="color: #000080;font-style:italic;">-- this will be used in the main loop</span>
cdCanvasFlush(cddbuffer)
<span style="color: #000000;">ypxl2</span> <span style="color: #0000FF;">:=</span> <span style="color: #7060A8;">floor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">yend</span><span style="color: #0000FF;">)</span>
return IUP_DEFAULT
<span style="color: #000000;">plot2</span><span style="color: #0000FF;">(</span><span style="color: #000000;">xpxl2</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">ypxl2</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">fpart</span><span style="color: #0000FF;">(</span><span style="color: #000000;">yend</span><span style="color: #0000FF;">),</span> <span style="color: #000000;">xgap</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">steep</span><span style="color: #0000FF;">)</span>
end function
 
<span style="color: #000080;font-style:italic;">-- main loop</span>
function map_cb(Ihandle ih)
<span style="color: #008080;">for</span> <span style="color: #000000;">x</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">xpxl1</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span> <span style="color: #008080;">to</span> <span style="color: #000000;">xpxl2</span><span style="color: #0000FF;">-</span><span style="color: #000000;">1</span> <span style="color: #008080;">do</span>
cdcanvas = cdCreateCanvas(CD_IUP, ih)
<span style="color: #000000;">plot2</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">,</span> <span style="color: #7060A8;">floor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">intery</span><span style="color: #0000FF;">),</span> <span style="color: #000000;">fpart</span><span style="color: #0000FF;">(</span><span style="color: #000000;">intery</span><span style="color: #0000FF;">),</span> <span style="color: #000000;">1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">steep</span><span style="color: #0000FF;">)</span>
cddbuffer = cdCreateCanvas(CD_DBUFFER, cdcanvas)
<span style="color: #000000;">intery</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">gradient</span>
cdCanvasSetBackground(cddbuffer, BACK)
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
cdCanvasSetForeground(cddbuffer, LINE)
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
return IUP_DEFAULT
end function
<span style="color: #008080;">procedure</span> <span style="color: #000000;">plot_4_points</span><span style="color: #0000FF;">(</span><span style="color: #004080;">integer</span> <span style="color: #000000;">cx</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">cy</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">atom</span> <span style="color: #000000;">f</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle1</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle2</span><span style="color: #0000FF;">=</span><span style="color: #000000;">360</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span><span style="color: #0000FF;">)</span>
 
<span style="color: #004080;">integer</span> <span style="color: #000000;">x1</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">cx</span><span style="color: #0000FF;">+</span><span style="color: #000000;">x</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">x2</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">cx</span><span style="color: #0000FF;">-</span><span style="color: #000000;">x</span><span style="color: #0000FF;">,</span>
function esc_close(Ihandle /*ih*/, atom c)
<span style="color: #000000;">y1</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">cy</span><span style="color: #0000FF;">+</span><span style="color: #000000;">y</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y2</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">cy</span><span style="color: #0000FF;">-</span><span style="color: #000000;">y</span>
if c=K_ESC then return IUP_CLOSE end if
<span style="color: #008080;">if</span> <span style="color: #000000;">angle</span><span style="color: #0000FF;"><</span><span style="color: #000000;">0</span> <span style="color: #008080;">or</span> <span style="color: #000000;">angle</span><span style="color: #0000FF;">></span><span style="color: #000000;">90.01</span> <span style="color: #008080;">then</span> <span style="color: #0000FF;">?</span><span style="color: #000000;">9</span><span style="color: #0000FF;">/</span><span style="color: #000000;">0</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
if c=' ' then
<span style="color: #008080;">if</span> <span style="color: #000000;">angle</span> <span style="color: #0000FF;">>=</span><span style="color: #000000;">angle1</span> <span style="color: #008080;">and</span> <span style="color: #000000;">angle</span> <span style="color: #0000FF;"><=</span><span style="color: #000000;">angle2</span> <span style="color: #008080;">then</span> <span style="color: #000000;">plot</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">f</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span> <span style="color: #000080;font-style:italic;">-- top right</span>
bresline = not bresline
<span style="color: #008080;">if</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">180</span><span style="color: #0000FF;">-</span><span style="color: #000000;">angle</span><span style="color: #0000FF;">)>=</span><span style="color: #000000;">angle1</span> <span style="color: #008080;">and</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">180</span><span style="color: #0000FF;">-</span><span style="color: #000000;">angle</span><span style="color: #0000FF;">)<=</span><span style="color: #000000;">angle2</span> <span style="color: #008080;">then</span> <span style="color: #000000;">plot</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x2</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">f</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span> <span style="color: #000080;font-style:italic;">-- top left</span>
IupRedraw(canvas)
<span style="color: #008080;">if</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">180</span><span style="color: #0000FF;">+</span><span style="color: #000000;">angle</span><span style="color: #0000FF;">)>=</span><span style="color: #000000;">angle1</span> <span style="color: #008080;">and</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">180</span><span style="color: #0000FF;">+</span><span style="color: #000000;">angle</span><span style="color: #0000FF;">)<=</span><span style="color: #000000;">angle2</span> <span style="color: #008080;">then</span> <span style="color: #000000;">plot</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x2</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y2</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">f</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span> <span style="color: #000080;font-style:italic;">-- btm left</span>
end if
<span style="color: #008080;">if</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">360</span><span style="color: #0000FF;">-</span><span style="color: #000000;">angle</span><span style="color: #0000FF;">)>=</span><span style="color: #000000;">angle1</span> <span style="color: #008080;">and</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">360</span><span style="color: #0000FF;">-</span><span style="color: #000000;">angle</span><span style="color: #0000FF;">)<=</span><span style="color: #000000;">angle2</span> <span style="color: #008080;">then</span> <span style="color: #000000;">plot</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">y2</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">f</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span> <span style="color: #000080;font-style:italic;">-- btm right</span>
return IUP_CONTINUE
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
end function
 
<span style="color: #008080;">procedure</span> <span style="color: #000000;">wu_ellipse</span><span style="color: #0000FF;">(</span><span style="color: #004080;">atom</span> <span style="color: #000000;">cx</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">cy</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">w</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">h</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle1</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle2</span><span style="color: #0000FF;">=</span><span style="color: #000000;">360</span><span style="color: #0000FF;">)</span>
procedure main()
<span style="color: #000080;font-style:italic;">--
IupOpen()
-- (draws a circle when w=h) credit:
canvas = IupCanvas(NULL)
-- https://yellowsplash.wordpress.com/2009/10/23/fast-antialiased-circles-and-ellipses-from-xiaolin-wus-concepts/
IupSetAttribute(canvas, "RASTERSIZE", "640x480")
--</span>
IupSetCallback(canvas, "MAP_CB", Icallback("map_cb"))
<span style="color: #008080;">if</span> <span style="color: #000000;">w</span><span style="color: #0000FF;"><=</span><span style="color: #000000;">0</span> <span style="color: #008080;">or</span> <span style="color: #000000;">h</span><span style="color: #0000FF;"><=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span> <span style="color: #008080;">return</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
IupSetCallback(canvas, "ACTION", Icallback("redraw_cb"))
<span style="color: #000000;">cx</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">round</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cx</span><span style="color: #0000FF;">)</span>
dlg = IupDialog(canvas)
<span style="color: #000000;">cy</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">round</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cy</span><span style="color: #0000FF;">)</span>
IupSetAttribute(dlg, "TITLE", TITLE)
<span style="color: #000000;">w</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">round</span><span style="color: #0000FF;">(</span><span style="color: #000000;">w</span><span style="color: #0000FF;">)</span>
IupSetCallback(dlg, "K_ANY", Icallback("esc_close"))
<span style="color: #000000;">h</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">round</span><span style="color: #0000FF;">(</span><span style="color: #000000;">h</span><span style="color: #0000FF;">)</span>
IupShow(dlg)
<span style="color: #000000;">angle1</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">mod</span><span style="color: #0000FF;">(</span><span style="color: #000000;">angle1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">360</span><span style="color: #0000FF;">)</span>
IupSetAttribute(canvas, "RASTERSIZE", NULL)
<span style="color: #000000;">angle2</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">mod</span><span style="color: #0000FF;">(</span><span style="color: #000000;">angle2</span><span style="color: #0000FF;">,</span><span style="color: #000000;">360</span><span style="color: #0000FF;">)</span>
IupMainLoop()
IupClose()
<span style="color: #000080;font-style:italic;">-- Match cdCanvasArc/Sector angles:</span>
end procedure
<span style="color: #000000;">angle1</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">atan2</span><span style="color: #0000FF;">((</span><span style="color: #000000;">h</span><span style="color: #0000FF;">/</span><span style="color: #000000;">2</span><span style="color: #0000FF;">)*</span><span style="color: #7060A8;">sin</span><span style="color: #0000FF;">(</span><span style="color: #000000;">angle1</span><span style="color: #0000FF;">*</span><span style="color: #004600;">CD_DEG2RAD</span><span style="color: #0000FF;">),</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">w</span><span style="color: #0000FF;">/</span><span style="color: #000000;">2</span><span style="color: #0000FF;">)*</span><span style="color: #7060A8;">cos</span><span style="color: #0000FF;">(</span><span style="color: #000000;">angle1</span><span style="color: #0000FF;">*</span><span style="color: #004600;">CD_DEG2RAD</span><span style="color: #0000FF;">))*</span><span style="color: #004600;">CD_RAD2DEG</span>
main()</lang>
<span style="color: #000000;">angle2</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">atan2</span><span style="color: #0000FF;">((</span><span style="color: #000000;">h</span><span style="color: #0000FF;">/</span><span style="color: #000000;">2</span><span style="color: #0000FF;">)*</span><span style="color: #7060A8;">sin</span><span style="color: #0000FF;">(</span><span style="color: #000000;">angle2</span><span style="color: #0000FF;">*</span><span style="color: #004600;">CD_DEG2RAD</span><span style="color: #0000FF;">),</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">w</span><span style="color: #0000FF;">/</span><span style="color: #000000;">2</span><span style="color: #0000FF;">)*</span><span style="color: #7060A8;">cos</span><span style="color: #0000FF;">(</span><span style="color: #000000;">angle2</span><span style="color: #0000FF;">*</span><span style="color: #004600;">CD_DEG2RAD</span><span style="color: #0000FF;">))*</span><span style="color: #004600;">CD_RAD2DEG</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">angle2</span><span style="color: #0000FF;"><=</span><span style="color: #000000;">angle1</span> <span style="color: #008080;">then</span> <span style="color: #000000;">angle2</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">360</span> <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">a</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">w</span><span style="color: #0000FF;">/</span><span style="color: #000000;">2</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">asq</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">a</span><span style="color: #0000FF;">*</span><span style="color: #000000;">a</span><span style="color: #0000FF;">,</span>
<span style="color: #000000;">b</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">h</span><span style="color: #0000FF;">/</span><span style="color: #000000;">2</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">bsq</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">b</span><span style="color: #0000FF;">*</span><span style="color: #000000;">b</span><span style="color: #0000FF;">,</span>
<span style="color: #000000;">sqab</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">sqrt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">asq</span><span style="color: #0000FF;">+</span><span style="color: #000000;">bsq</span><span style="color: #0000FF;">),</span>
<span style="color: #000000;">ffd</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">round</span><span style="color: #0000FF;">(</span><span style="color: #000000;">asq</span><span style="color: #0000FF;">/</span><span style="color: #000000;">sqab</span><span style="color: #0000FF;">),</span> <span style="color: #000080;font-style:italic;">-- forty-five-degree coord</span>
<span style="color: #000000;">xj</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">yj</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">frc</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">flr</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle</span>
<span style="color: #000080;font-style:italic;">-- draw top right, and the 3 mirrors of it in horizontal fashion
-- (ie 90 to 45 degrees for a circle)</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">xi</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span> <span style="color: #008080;">to</span> <span style="color: #000000;">ffd</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">yj</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">b</span><span style="color: #0000FF;">*</span><span style="color: #7060A8;">sqrt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">-</span><span style="color: #000000;">xi</span><span style="color: #0000FF;">*</span><span style="color: #000000;">xi</span><span style="color: #0000FF;">/</span><span style="color: #000000;">asq</span><span style="color: #0000FF;">)</span> <span style="color: #000080;font-style:italic;">-- real y value</span>
<span style="color: #000000;">frc</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">fpart</span><span style="color: #0000FF;">(</span><span style="color: #000000;">yj</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">flr</span> <span style="color: #0000FF;">:=</span> <span style="color: #7060A8;">floor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">yj</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">angle</span> <span style="color: #0000FF;">:=</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">xi</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span><span style="color: #0000FF;">?</span><span style="color: #000000;">90</span><span style="color: #0000FF;">:</span><span style="color: #7060A8;">arctan</span><span style="color: #0000FF;">(</span><span style="color: #000000;">yj</span><span style="color: #0000FF;">/</span><span style="color: #000000;">xi</span><span style="color: #0000FF;">)*</span><span style="color: #004600;">CD_RAD2DEG</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">plot_4_points</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cx</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">cy</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">xi</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">flr</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">1</span><span style="color: #0000FF;">-</span><span style="color: #000000;">frc</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle2</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">plot_4_points</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cx</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">cy</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">xi</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">flr</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">frc</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle2</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #000080;font-style:italic;">-- switch from horizontal to vertial mode for the rest, ditto 3
-- (ie 45..0 degrees for a circle)</span>
<span style="color: #000000;">ffd</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">round</span><span style="color: #0000FF;">(</span><span style="color: #000000;">bsq</span><span style="color: #0000FF;">/</span><span style="color: #000000;">sqab</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">for</span> <span style="color: #000000;">yi</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span> <span style="color: #008080;">to</span> <span style="color: #000000;">ffd</span> <span style="color: #008080;">do</span>
<span style="color: #000000;">xj</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">a</span><span style="color: #0000FF;">*</span><span style="color: #7060A8;">sqrt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">-</span><span style="color: #000000;">yi</span><span style="color: #0000FF;">*</span><span style="color: #000000;">yi</span><span style="color: #0000FF;">/</span><span style="color: #000000;">bsq</span><span style="color: #0000FF;">)</span> <span style="color: #000080;font-style:italic;">-- real x value</span>
<span style="color: #000000;">frc</span> <span style="color: #0000FF;">:=</span> <span style="color: #000000;">fpart</span><span style="color: #0000FF;">(</span><span style="color: #000000;">xj</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">flr</span> <span style="color: #0000FF;">:=</span> <span style="color: #7060A8;">floor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">xj</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">angle</span> <span style="color: #0000FF;">=</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">xj</span><span style="color: #0000FF;">=</span><span style="color: #000000;">0</span><span style="color: #0000FF;">?</span><span style="color: #000000;">0</span><span style="color: #0000FF;">:</span><span style="color: #7060A8;">arctan</span><span style="color: #0000FF;">(</span><span style="color: #000000;">yi</span><span style="color: #0000FF;">/</span><span style="color: #000000;">xj</span><span style="color: #0000FF;">)*</span><span style="color: #004600;">CD_RAD2DEG</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">plot_4_points</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">cx</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">cy</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">flr</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">yi</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">1</span><span style="color: #0000FF;">-</span><span style="color: #000000;">frc</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle2</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">plot_4_points</span> <span style="color: #0000FF;">(</span><span style="color: #000000;">cx</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">cy</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">flr</span><span style="color: #0000FF;">+</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">yi</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">frc</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle1</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle2</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">angle</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">redraw_cb</span><span style="color: #0000FF;">(</span><span style="color: #004080;">Ihandle</span> <span style="color: #000080;font-style:italic;">/*ih*/</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">integer</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">w</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">h</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">sq_sub</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">IupGetIntInt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">canvas</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"DRAWSIZE"</span><span style="color: #0000FF;">),</span><span style="color: #000000;">10</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">cdCanvasActivate</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cddbuffer</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">cdCanvasClear</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cddbuffer</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;">cdCanvasSetLineWidth</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cddbuffer</span><span style="color: #0000FF;">,</span><span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">wuline</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;">wuline</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">wu_line</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">wu_line</span><span style="color: #0000FF;">(</span><span style="color: #000000;">w</span><span style="color: #0000FF;">,</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">wu_line</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">h</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">wu_line</span><span style="color: #0000FF;">(</span><span style="color: #000000;">w</span><span style="color: #0000FF;">,</span><span style="color: #000000;">h</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">else</span>
<span style="color: #7060A8;">cdCanvasLine</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cddbuffer</span><span style="color: #0000FF;">,</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">cdCanvasLine</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cddbuffer</span><span style="color: #0000FF;">,</span><span style="color: #000000;">w</span><span style="color: #0000FF;">,</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">cdCanvasLine</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cddbuffer</span><span style="color: #0000FF;">,</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">h</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">cdCanvasLine</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cddbuffer</span><span style="color: #0000FF;">,</span><span style="color: #000000;">w</span><span style="color: #0000FF;">,</span><span style="color: #000000;">h</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</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;">wuline</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">wu_ellipse</span><span style="color: #0000FF;">(</span><span style="color: #000000;">200</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">)</span>
<span style="color: #000080;font-style:italic;">-- cdCanvasSector(cddbuffer, 200, 200, 200, 200, 0, 360) </span>
<span style="color: #000000;">wu_ellipse</span><span style="color: #0000FF;">(</span><span style="color: #000000;">200</span><span style="color: #0000FF;">,</span><span style="color: #000000;">200</span><span style="color: #0000FF;">,</span><span style="color: #000000;">300</span><span style="color: #0000FF;">,</span><span style="color: #000000;">100</span><span style="color: #0000FF;">)</span>
<span style="color: #000080;font-style:italic;">-- wu_ellipse(200,200,300,100,15,85)
-- cdCanvasArc(cddbuffer, 205, 205, 300, 100, 15, 85) </span>
<span style="color: #008080;">else</span>
<span style="color: #7060A8;">cdCanvasArc</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cddbuffer</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">200</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">200</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">200</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">200</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">360</span><span style="color: #0000FF;">)</span>
<span style="color: #000080;font-style:italic;">-- cdCanvasSector(cddbuffer, 200, 200, 200, 200, 0, 360) </span>
<span style="color: #7060A8;">cdCanvasArc</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cddbuffer</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">200</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">200</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">300</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">100</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">360</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #000080;font-style:italic;">--test - it works (much better) if you draw the polygon /after/ the lines!!
-- cdCanvasBegin(cddbuffer,CD_FILL)
-- cdCanvasVertex(cddbuffer,w,h)
-- cdCanvasVertex(cddbuffer,0,h)
-- cdCanvasVertex(cddbuffer,200,200)
-- cdCanvasEnd(cddbuffer)
--/test</span>
<span style="color: #7060A8;">cdCanvasFlush</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cddbuffer</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">USE_OPENGL</span> <span style="color: #008080;">then</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;">IupGLSwapBuffers</span><span style="color: #0000FF;">(</span><span style="color: #000000;">canvas</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;">if</span>
<span style="color: #008080;">return</span> <span style="color: #004600;">IUP_DEFAULT</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">map_cb</span><span style="color: #0000FF;">(</span><span style="color: #004080;">Ihandle</span> <span style="color: #000000;">ih</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">USE_OPENGL</span> <span style="color: #008080;">then</span>
<span style="color: #7060A8;">IupGLMakeCurrent</span><span style="color: #0000FF;">(</span><span style="color: #000000;">canvas</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: #000000;">cdcanvas</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">cdCreateCanvas</span><span style="color: #0000FF;">(</span><span style="color: #004600;">CD_IUP</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">canvas</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">else</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">res</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">IupGetDouble</span><span style="color: #0000FF;">(</span><span style="color: #004600;">NULL</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"SCREENDPI"</span><span style="color: #0000FF;">)/</span><span style="color: #000000;">25.4</span>
<span style="color: #000000;">cdcanvas</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">cdCreateCanvas</span><span style="color: #0000FF;">(</span><span style="color: #004600;">CD_GL</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"10x10 %g"</span><span style="color: #0000FF;">,</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">res</span><span style="color: #0000FF;">})</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #000000;">cddbuffer</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">cdcanvas</span>
<span style="color: #008080;">else</span>
<span style="color: #000000;">cdcanvas</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">cdCreateCanvas</span><span style="color: #0000FF;">(</span><span style="color: #004600;">CD_IUP</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">ih</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">cddbuffer</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">cdCreateCanvas</span><span style="color: #0000FF;">(</span><span style="color: #004600;">CD_DBUFFER</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">cdcanvas</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #7060A8;">cdCanvasSetBackground</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cddbuffer</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">BACK</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">cdCanvasSetForeground</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cddbuffer</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">LINE</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">return</span> <span style="color: #004600;">IUP_DEFAULT</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">canvas_resize_cb</span><span style="color: #0000FF;">(</span><span style="color: #004080;">Ihandle</span> <span style="color: #000080;font-style:italic;">/*canvas*/</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">USE_OPENGL</span> <span style="color: #008080;">then</span>
<span style="color: #004080;">integer</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">canvas_width</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">canvas_height</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">IupGetIntInt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">canvas</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"DRAWSIZE"</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">res</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">IupGetDouble</span><span style="color: #0000FF;">(</span><span style="color: #004600;">NULL</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"SCREENDPI"</span><span style="color: #0000FF;">)/</span><span style="color: #000000;">25.4</span>
<span style="color: #7060A8;">cdCanvasSetAttribute</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cdcanvas</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"SIZE"</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"%dx%d %g"</span><span style="color: #0000FF;">,</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">canvas_width</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">canvas_height</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">res</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: #004600;">IUP_DEFAULT</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;">string</span> <span style="color: #000000;">title</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">TITLE</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">USE_OPENGL</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">title</span> <span style="color: #0000FF;">&=</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">wuline</span><span style="color: #0000FF;">?</span><span style="color: #008000;">" (wu_line)"</span><span style="color: #0000FF;">:</span><span style="color: #008000;">" (opengl)"</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">else</span>
<span style="color: #000000;">title</span> <span style="color: #0000FF;">&=</span> <span style="color: #008080;">iff</span><span style="color: #0000FF;">(</span><span style="color: #000000;">wuline</span><span style="color: #0000FF;">?</span><span style="color: #008000;">" (anti-aliased)"</span><span style="color: #0000FF;">:</span><span style="color: #008000;">" (bresenham)"</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</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: #000000;">title</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: #000080;font-style:italic;">/*ih*/</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;">wuline</span> <span style="color: #0000FF;">=</span> <span style="color: #008080;">not</span> <span style="color: #000000;">wuline</span>
<span style="color: #000000;">set_title</span><span style="color: #0000FF;">()</span>
<span style="color: #7060A8;">IupRedraw</span><span style="color: #0000FF;">(</span><span style="color: #000000;">canvas</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: #004600;">IUP_CONTINUE</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: #008080;">if</span> <span style="color: #000000;">USE_OPENGL</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">canvas</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">IupGLCanvas</span><span style="color: #0000FF;">()</span>
<span style="color: #7060A8;">IupSetAttribute</span><span style="color: #0000FF;">(</span><span style="color: #000000;">canvas</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"BUFFER"</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"DOUBLE"</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">else</span>
<span style="color: #000000;">canvas</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">IupCanvas</span><span style="color: #0000FF;">()</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #7060A8;">IupSetAttribute</span><span style="color: #0000FF;">(</span><span style="color: #000000;">canvas</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"RASTERSIZE"</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"640x480"</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">IupSetCallbacks</span><span style="color: #0000FF;">(</span><span style="color: #000000;">canvas</span><span style="color: #0000FF;">,</span> <span style="color: #0000FF;">{</span><span style="color: #008000;">"MAP_CB"</span><span style="color: #0000FF;">,</span> <span style="color: #7060A8;">Icallback</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"map_cb"</span><span style="color: #0000FF;">),</span>
<span style="color: #008000;">"ACTION"</span><span style="color: #0000FF;">,</span> <span style="color: #7060A8;">Icallback</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"redraw_cb"</span><span style="color: #0000FF;">),</span>
<span style="color: #008000;">"RESIZE_CB"</span><span style="color: #0000FF;">,</span> <span style="color: #7060A8;">Icallback</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"canvas_resize_cb"</span><span style="color: #0000FF;">)})</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;">canvas</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">set_title</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: #7060A8;">IupShow</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dlg</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">IupSetAttribute</span><span style="color: #0000FF;">(</span><span style="color: #000000;">canvas</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"RASTERSIZE"</span><span style="color: #0000FF;">,</span> <span style="color: #004600;">NULL</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|PicoLisp}}==
Petelomax
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edits

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