Simple turtle graphics: Difference between revisions
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https://imgur.com/4V1UrcN
=={{header|Phix}}==
{{libheader|Phix/pGUI}}
{{libheader|Phix/online}}
You can run this online [http://phix.x10.mx/p2js/simpleturtlegraphics.htm here].
<!--<lang Phix>(phixonline)-->
<span style="color: #000080;font-style:italic;">-- demo\rosetta\Simple_turtle_graphics.exw</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: #004080;">cdCanvas</span> <span style="color: #000000;">cdcanvas</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">x</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">,</span>
<span style="color: #000000;">y</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">,</span>
<span style="color: #000000;">direction</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0</span>
<span style="color: #004080;">bool</span> <span style="color: #000000;">pen_down</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">true</span>
<span style="color: #008080;">procedure</span> <span style="color: #000000;">walk</span><span style="color: #0000FF;">(</span><span style="color: #004080;">atom</span> <span style="color: #000000;">distance</span><span style="color: #0000FF;">)</span>
<span style="color: #000080;font-style:italic;">//
// Move forward by distance pixels.
//</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">start_x</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">x</span><span style="color: #0000FF;">,</span>
<span style="color: #000000;">start_y</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">y</span><span style="color: #0000FF;">,</span>
<span style="color: #000000;">angle</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">direction</span><span style="color: #0000FF;">*</span><span style="color: #004600;">PI</span><span style="color: #0000FF;">/</span><span style="color: #000000;">180</span><span style="color: #0000FF;">,</span>
<span style="color: #000000;">dy</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">distance</span><span style="color: #0000FF;">*</span><span style="color: #7060A8;">cos</span><span style="color: #0000FF;">(</span><span style="color: #000000;">angle</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">x</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">distance</span><span style="color: #0000FF;">*</span><span style="color: #7060A8;">sin</span><span style="color: #0000FF;">(</span><span style="color: #000000;">angle</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">y</span> <span style="color: #0000FF;">+=</span> <span style="color: #000000;">distance</span><span style="color: #0000FF;">*</span><span style="color: #7060A8;">cos</span><span style="color: #0000FF;">(</span><span style="color: #000000;">angle</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">pen_down</span> <span style="color: #008080;">then</span>
<span style="color: #7060A8;">cdCanvasLine</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cdcanvas</span><span style="color: #0000FF;">,</span><span style="color: #000000;">start_x</span><span style="color: #0000FF;">,</span><span style="color: #000000;">start_y</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: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #008080;">procedure</span> <span style="color: #000000;">right</span><span style="color: #0000FF;">(</span><span style="color: #004080;">atom</span> <span style="color: #000000;">angle</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">direction</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">remainder</span><span style="color: #0000FF;">(</span><span style="color: #000000;">direction</span><span style="color: #0000FF;">+</span><span style="color: #000000;">angle</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;">procedure</span>
<span style="color: #008080;">procedure</span> <span style="color: #000000;">left</span><span style="color: #0000FF;">(</span><span style="color: #004080;">atom</span> <span style="color: #000000;">angle</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">right</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: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #008080;">procedure</span> <span style="color: #000000;">penup</span><span style="color: #0000FF;">()</span>
<span style="color: #000000;">pen_down</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">false</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #008080;">procedure</span> <span style="color: #000000;">pendown</span><span style="color: #0000FF;">(</span><span style="color: #004080;">atom</span> <span style="color: #000000;">colour</span><span style="color: #0000FF;">=</span><span style="color: #004600;">CD_BLACK</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">pen_down</span> <span style="color: #0000FF;">=</span> <span style="color: #004600;">true</span>
<span style="color: #7060A8;">cdCanvasSetForeground</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cdcanvas</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">colour</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #008080;">procedure</span> <span style="color: #000000;">move</span><span style="color: #0000FF;">(</span><span style="color: #004080;">sequence</span> <span style="color: #000000;">s</span><span style="color: #0000FF;">)</span>
<span style="color: #000080;font-style:italic;">-- s is a list of angles (odd elements)
-- and distances (even elements)</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: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
<span style="color: #008080;">if</span> <span style="color: #7060A8;">odd</span><span style="color: #0000FF;">(</span><span style="color: #000000;">i</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">right</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">])</span>
<span style="color: #008080;">else</span>
<span style="color: #000000;">walk</span><span style="color: #0000FF;">(</span><span style="color: #000000;">s</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</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;">for</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #008080;">procedure</span> <span style="color: #000000;">rectangle</span><span style="color: #0000FF;">(</span><span style="color: #004080;">atom</span> <span style="color: #000000;">width</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">height</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">move</span><span style="color: #0000FF;">({</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">height</span><span style="color: #0000FF;">,</span><span style="color: #000000;">90</span><span style="color: #0000FF;">,</span><span style="color: #000000;">width</span><span style="color: #0000FF;">,</span><span style="color: #000000;">90</span><span style="color: #0000FF;">,</span><span style="color: #000000;">height</span><span style="color: #0000FF;">,</span><span style="color: #000000;">90</span><span style="color: #0000FF;">,</span><span style="color: #000000;">width</span><span style="color: #0000FF;">,</span><span style="color: #000000;">90</span><span style="color: #0000FF;">})</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #008080;">procedure</span> <span style="color: #000000;">draw_house</span><span style="color: #0000FF;">(</span><span style="color: #004080;">atom</span> <span style="color: #000000;">width</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">height</span><span style="color: #0000FF;">)</span>
<span style="color: #000080;font-style:italic;">//
// Draw a house at the current x,y
// direction must be 0 for house to be upright
//
// house walls</span>
<span style="color: #000000;">rectangle</span><span style="color: #0000FF;">(</span><span style="color: #000000;">width</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">height</span><span style="color: #0000FF;">)</span>
<span style="color: #000080;font-style:italic;">// door (maybe some windows too would be nice...)</span>
<span style="color: #000000;">penup</span><span style="color: #0000FF;">()</span>
<span style="color: #000000;">move</span><span style="color: #0000FF;">({</span><span style="color: #000000;">90</span><span style="color: #0000FF;">,</span><span style="color: #000000;">width</span><span style="color: #0000FF;">/</span><span style="color: #000000;">7</span><span style="color: #0000FF;">,-</span><span style="color: #000000;">90</span><span style="color: #0000FF;">})</span>
<span style="color: #000000;">pendown</span><span style="color: #0000FF;">(</span><span style="color: #004600;">CD_BLUE</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">rectangle</span><span style="color: #0000FF;">(</span><span style="color: #000000;">width</span><span style="color: #0000FF;">/</span><span style="color: #000000;">8</span><span style="color: #0000FF;">,</span><span style="color: #000000;">height</span><span style="color: #0000FF;">/</span><span style="color: #000000;">2.5</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">penup</span><span style="color: #0000FF;">()</span>
<span style="color: #000000;">move</span><span style="color: #0000FF;">({-</span><span style="color: #000000;">90</span><span style="color: #0000FF;">,</span><span style="color: #000000;">width</span><span style="color: #0000FF;">/</span><span style="color: #000000;">7</span><span style="color: #0000FF;">,</span><span style="color: #000000;">90</span><span style="color: #0000FF;">})</span>
<span style="color: #000080;font-style:italic;">// roof</span>
<span style="color: #000000;">walk</span><span style="color: #0000FF;">(</span><span style="color: #000000;">height</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">pendown</span><span style="color: #0000FF;">(</span><span style="color: #004600;">CD_RED</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">a</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">arctan</span><span style="color: #0000FF;">(</span><span style="color: #000000;">width</span><span style="color: #0000FF;">/</span><span style="color: #000000;">height</span><span style="color: #0000FF;">)*</span><span style="color: #004600;">CD_RAD2DEG</span><span style="color: #0000FF;">,</span>
<span style="color: #000000;">d</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">sqrt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">width</span><span style="color: #0000FF;">*</span><span style="color: #000000;">width</span><span style="color: #0000FF;">+</span><span style="color: #000000;">height</span><span style="color: #0000FF;">*</span><span style="color: #000000;">height</span><span style="color: #0000FF;">)/</span><span style="color: #000000;">2</span>
<span style="color: #000000;">move</span><span style="color: #0000FF;">({</span><span style="color: #000000;">a</span><span style="color: #0000FF;">,</span><span style="color: #000000;">d</span><span style="color: #0000FF;">,</span><span style="color: #000000;">180</span><span style="color: #0000FF;">-</span><span style="color: #000000;">a</span><span style="color: #0000FF;">*</span><span style="color: #000000;">2</span><span style="color: #0000FF;">,</span><span style="color: #000000;">d</span><span style="color: #0000FF;">})</span>
<span style="color: #000000;">penup</span><span style="color: #0000FF;">()</span>
<span style="color: #000080;font-style:italic;">// return to origin({qw,qh}) and direction 0:</span>
<span style="color: #000000;">move</span><span style="color: #0000FF;">({</span><span style="color: #000000;">90</span><span style="color: #0000FF;">+</span><span style="color: #000000;">a</span><span style="color: #0000FF;">,</span><span style="color: #000000;">width</span><span style="color: #0000FF;">,-</span><span style="color: #000000;">90</span><span style="color: #0000FF;">,</span><span style="color: #000000;">height</span><span style="color: #0000FF;">,</span><span style="color: #000000;">180</span><span style="color: #0000FF;">})</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #008080;">procedure</span> <span style="color: #000000;">draw_barchart</span><span style="color: #0000FF;">(</span><span style="color: #004080;">sequence</span> <span style="color: #000000;">nums</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">atom</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: #000080;font-style:italic;">// draw a barchart occupying the middle 60% of w,h
// nums can contain +ve and/or -ve values.</span>
<span style="color: #004080;">integer</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;">nums</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">mx</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">max</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">max</span><span style="color: #0000FF;">(</span><span style="color: #000000;">nums</span><span style="color: #0000FF;">),</span><span style="color: #000000;">0</span><span style="color: #0000FF;">),</span>
<span style="color: #000000;">mn</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">min</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">min</span><span style="color: #0000FF;">(</span><span style="color: #000000;">nums</span><span style="color: #0000FF;">),</span><span style="color: #000000;">0</span><span style="color: #0000FF;">),</span>
<span style="color: #000000;">r</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">mx</span><span style="color: #0000FF;">-</span><span style="color: #000000;">mn</span><span style="color: #0000FF;">,</span> <span style="color: #000080;font-style:italic;">-- range</span>
<span style="color: #000000;">zl</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">abs</span><span style="color: #0000FF;">(</span><span style="color: #000000;">mn</span><span style="color: #0000FF;">)/</span><span style="color: #000000;">r</span><span style="color: #0000FF;">*</span><span style="color: #000000;">h</span><span style="color: #0000FF;">*</span><span style="color: #000000;">0.6</span><span style="color: #0000FF;">+</span><span style="color: #000000;">h</span><span style="color: #0000FF;">/</span><span style="color: #000000;">5</span><span style="color: #0000FF;">,</span> <span style="color: #000080;font-style:italic;">-- zero line</span>
<span style="color: #000000;">bw</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">w</span><span style="color: #0000FF;">*</span><span style="color: #000000;">0.6</span><span style="color: #0000FF;">/</span><span style="color: #000000;">n</span> <span style="color: #000080;font-style:italic;">-- bar width</span>
<span style="color: #000000;">move</span><span style="color: #0000FF;">({</span><span style="color: #000000;">90</span><span style="color: #0000FF;">,</span><span style="color: #000000;">w</span><span style="color: #0000FF;">/</span><span style="color: #000000;">5</span><span style="color: #0000FF;">,-</span><span style="color: #000000;">90</span><span style="color: #0000FF;">,</span><span style="color: #000000;">zl</span><span style="color: #0000FF;">})</span>
<span style="color: #000000;">pendown</span><span style="color: #0000FF;">()</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;">ni</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">nums</span><span style="color: #0000FF;">[</span><span style="color: #000000;">i</span><span style="color: #0000FF;">]/</span><span style="color: #000000;">r</span><span style="color: #0000FF;">*</span><span style="color: #000000;">h</span><span style="color: #0000FF;">*</span><span style="color: #000000;">0.6</span>
<span style="color: #008080;">if</span> <span style="color: #000000;">ni</span><span style="color: #0000FF;">></span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span>
<span style="color: #000000;">rectangle</span><span style="color: #0000FF;">(</span><span style="color: #000000;">bw</span><span style="color: #0000FF;">,</span><span style="color: #000000;">ni</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">else</span>
<span style="color: #000000;">pendown</span><span style="color: #0000FF;">(</span><span style="color: #004600;">CD_RED</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">right</span><span style="color: #0000FF;">(</span><span style="color: #000000;">90</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">rectangle</span><span style="color: #0000FF;">(-</span><span style="color: #000000;">ni</span><span style="color: #0000FF;">,</span><span style="color: #000000;">bw</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">left</span><span style="color: #0000FF;">(</span><span style="color: #000000;">90</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">pendown</span><span style="color: #0000FF;">(</span><span style="color: #004600;">CD_BLACK</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #000000;">move</span><span style="color: #0000FF;">({</span><span style="color: #000000;">90</span><span style="color: #0000FF;">,</span><span style="color: #000000;">bw</span><span style="color: #0000FF;">,-</span><span style="color: #000000;">90</span><span style="color: #0000FF;">})</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
<span style="color: #000000;">penup</span><span style="color: #0000FF;">()</span>
<span style="color: #000080;font-style:italic;">// return to origin({w/2,0}) and direction 0:</span>
<span style="color: #000000;">move</span><span style="color: #0000FF;">({</span><span style="color: #000000;">180</span><span style="color: #0000FF;">,</span><span style="color: #000000;">zl</span><span style="color: #0000FF;">,</span><span style="color: #000000;">90</span><span style="color: #0000FF;">,</span><span style="color: #000000;">w</span><span style="color: #0000FF;">/</span><span style="color: #000000;">5</span><span style="color: #0000FF;">+</span><span style="color: #000000;">bw</span><span style="color: #0000FF;">*</span><span style="color: #000000;">n</span><span style="color: #0000FF;">,</span><span style="color: #000000;">90</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;">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: #000080;font-style:italic;">/*posx*/</span><span style="color: #0000FF;">,</span> <span style="color: #000080;font-style:italic;">/*posy*/</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">integer</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">width</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">height</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">cdCanvasGetSize</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cdcanvas</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">cdCanvasActivate</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cdcanvas</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">cdCanvasClear</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cdcanvas</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">qw</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">width</span><span style="color: #0000FF;">/</span><span style="color: #000000;">4</span><span style="color: #0000FF;">,</span>
<span style="color: #000000;">qh</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">height</span><span style="color: #0000FF;">/</span><span style="color: #000000;">4</span>
<span style="color: #000000;">penup</span><span style="color: #0000FF;">()</span>
<span style="color: #000000;">move</span><span style="color: #0000FF;">({</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span><span style="color: #000000;">qh</span><span style="color: #0000FF;">,</span><span style="color: #000000;">90</span><span style="color: #0000FF;">,</span><span style="color: #000000;">qw</span><span style="color: #0000FF;">,-</span><span style="color: #000000;">90</span><span style="color: #0000FF;">})</span>
<span style="color: #000000;">pendown</span><span style="color: #0000FF;">()</span>
<span style="color: #000000;">draw_house</span><span style="color: #0000FF;">(</span><span style="color: #000000;">qw</span><span style="color: #0000FF;">,</span><span style="color: #000000;">qh</span><span style="color: #0000FF;">)</span> <span style="color: #000080;font-style:italic;">-- (at current x,y)</span>
<span style="color: #000000;">penup</span><span style="color: #0000FF;">()</span>
<span style="color: #000000;">move</span><span style="color: #0000FF;">({</span><span style="color: #000000;">180</span><span style="color: #0000FF;">,</span><span style="color: #000000;">qh</span><span style="color: #0000FF;">,</span><span style="color: #000000;">90</span><span style="color: #0000FF;">,</span><span style="color: #000000;">qw</span><span style="color: #0000FF;">,</span><span style="color: #000000;">90</span><span style="color: #0000FF;">})</span> <span style="color: #000080;font-style:italic;">-- return to {0,0}</span>
<span style="color: #000000;">move</span><span style="color: #0000FF;">({</span><span style="color: #000000;">90</span><span style="color: #0000FF;">,</span><span style="color: #000000;">width</span><span style="color: #0000FF;">/</span><span style="color: #000000;">2</span><span style="color: #0000FF;">,-</span><span style="color: #000000;">90</span><span style="color: #0000FF;">})</span> <span style="color: #000080;font-style:italic;">-- barchart in the right half</span>
<span style="color: #000000;">draw_barchart</span><span style="color: #0000FF;">({</span><span style="color: #000000;">0.5</span><span style="color: #0000FF;">,</span> <span style="color: #0000FF;">-</span><span style="color: #000000;">4</span><span style="color: #0000FF;">/</span><span style="color: #000000;">3</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">2</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">1.3</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">0.5</span><span style="color: #0000FF;">},</span><span style="color: #000000;">width</span><span style="color: #0000FF;">/</span><span style="color: #000000;">2</span><span style="color: #0000FF;">,</span><span style="color: #000000;">height</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">move</span><span style="color: #0000FF;">({-</span><span style="color: #000000;">90</span><span style="color: #0000FF;">,</span><span style="color: #000000;">width</span><span style="color: #0000FF;">/</span><span style="color: #000000;">2</span><span style="color: #0000FF;">,</span><span style="color: #000000;">90</span><span style="color: #0000FF;">})</span> <span style="color: #000080;font-style:italic;">-- return to {0,0}
-- sanity checks</span>
<span style="color: #008080;">if</span> <span style="color: #7060A8;">round</span><span style="color: #0000FF;">(</span><span style="color: #000000;">x</span><span style="color: #0000FF;">)!=</span><span style="color: #000000;">0</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>
<span style="color: #008080;">if</span> <span style="color: #7060A8;">round</span><span style="color: #0000FF;">(</span><span style="color: #000000;">y</span><span style="color: #0000FF;">)!=</span><span style="color: #000000;">0</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>
<span style="color: #008080;">if</span> <span style="color: #7060A8;">round</span><span style="color: #0000FF;">(</span><span style="color: #000000;">direction</span><span style="color: #0000FF;">)!=</span><span style="color: #000000;">0</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>
<span style="color: #7060A8;">cdCanvasFlush</span><span style="color: #0000FF;">(</span><span style="color: #000000;">cdcanvas</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: #7060A8;">IupOpen</span><span style="color: #0000FF;">()</span>
<span style="color: #004080;">Ihandle</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: #7060A8;">Icallback</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"redraw_cb"</span><span style="color: #0000FF;">),</span><span style="color: #008000;">"RASTERSIZE=600x400"</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: #008000;">`TITLE="Simple turtle graphics"`</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">IupMap</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dlg</span><span style="color: #0000FF;">)</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: #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: #000080;font-style:italic;">-- release the minimum limitation</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>
<!--</lang>-->
=={{header|Python}}==
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