Curve that touches three points: Difference between revisions

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 ::# &nbsp;Do not use functions of a library, implement the curve() function yourself
 ::# &nbsp;coordinates:(x,y) starting point (10,10) medium point (100,200) final point (200,10)
 =={{header|Go}}==
@@ Line 57: / Line 54: @@
     dc.SavePNG("quadratic_curve.png")
 }</lang>
 =={{header|J}}==
@@ Line 192: / Line 188: @@
 [https://github.com/SqrtNegInf/Rosettacode-Perl5-Smoke/blob/master/ref/curve-3-points.svg Hilbert curve passing through 3 defined points] (offsite image)
-=={{header|Perl 6}}==
+=={{header|Phix}}==
+{{trans|zkl}}
+<lang Phix>include pGUI.e
+Ihandle dlg, canvas
+cdCanvas cddbuffer, cdcanvas
+enum X, Y
+constant p = {{10,10},{100,200},{200,10}}
+function lagrange(atom x)
+   return (x - p[2][X])*(x - p[3][X])/(p[1][X] - p[2][X])/(p[1][X] - p[3][X])*p[1][Y] +
+          (x - p[1][X])*(x - p[3][X])/(p[2][X] - p[1][X])/(p[2][X] - p[3][X])*p[2][Y] +
+          (x - p[1][X])*(x - p[2][X])/(p[3][X] - p[1][X])/(p[3][X] - p[2][X])*p[3][Y]
+end function
+function getPoints(integer n)
+    sequence pts = {}
+    atom {dx,pt,cnt} := {(p[2][X] - p[1][X])/n, p[1][X], n}
+    for j=1 to 2 do
+        for i=0 to cnt do
+            atom x := pt + dx*i;
+            pts = append(pts,{x,lagrange(x)});
+        end for
+        {dx,pt,cnt} = {(p[3][X] - p[2][X])/n, p[2][X], n+1};
+    end for
+    return pts
+end function
+procedure draw_cross(sequence xy)
+    integer {x,y} = xy
+    cdCanvasLine(cddbuffer, x-3, y, x+3, y)
+    cdCanvasLine(cddbuffer, x, y-3, x, y+3)
+end procedure
+function redraw_cb(Ihandle /*ih*/, integer /*posx*/, integer /*posy*/)
+    cdCanvasActivate(cddbuffer)
+    cdCanvasSetForeground(cddbuffer, CD_BLUE)
+    cdCanvasBegin(cddbuffer,CD_OPEN_LINES)
+    atom {x,y} = {p[1][X], p[1][Y]}; -- curve starting point
+    cdCanvasVertex(cddbuffer, x, y)
+    sequence pts = getPoints(50)
+    for i=1 to length(pts) do
+        {x,y} = pts[i]
+        cdCanvasVertex(cddbuffer, x, y)
+    end for
+    cdCanvasEnd(cddbuffer)
+    cdCanvasSetForeground(cddbuffer, CD_RED)
+    for i=1 to length(p) do draw_cross(p[i]) end for
+    cdCanvasFlush(cddbuffer)
+    return IUP_DEFAULT
+end function
+function map_cb(Ihandle ih)
+    cdcanvas = cdCreateCanvas(CD_IUP, ih)
+    cddbuffer = cdCreateCanvas(CD_DBUFFER, cdcanvas)
+    cdCanvasSetBackground(cddbuffer, CD_WHITE)
+    return IUP_DEFAULT
+end function
+procedure main()
+    IupOpen()
+    canvas = IupCanvas(NULL)
+    IupSetAttribute(canvas, "RASTERSIZE", "220x220")
+    IupSetCallback(canvas, "MAP_CB", Icallback("map_cb"))
+    dlg = IupDialog(canvas,"DIALOGFRAME=YES")
+    IupSetAttribute(dlg, "TITLE", "Quadratic curve")
+    IupSetCallback(canvas, "ACTION", Icallback("redraw_cb"))
+    IupCloseOnEscape(dlg)
+    IupMap(dlg)
+    IupSetAttribute(canvas, "RASTERSIZE", NULL)
+    IupShowXY(dlg,IUP_CENTER,IUP_CENTER)
+    IupMainLoop()
+    IupClose()
+end procedure
+main()</lang>
+=={{header|Raku}}==
+(formerly Perl 6)
 {{works with|Rakudo|2018.10}}
 Kind of bogus. There are an infinite number of curves that pass through those three points. I'll assume a quadratic curve. Lots of bits and pieces borrowed from other tasks to avoid relying on library functions.
@@ Line 289: / Line 366: @@
 }</lang>
 See [https://github.com/thundergnat/rc/blob/master/img/Curve-3-points-perl6.png Curve-3-points-perl6.png] (offsite .png image)
-=={{header|Phix}}==
-{{trans|zkl}}
-<lang Phix>include pGUI.e
-Ihandle dlg, canvas
-cdCanvas cddbuffer, cdcanvas
-enum X, Y
-constant p = {{10,10},{100,200},{200,10}}
-function lagrange(atom x)
-   return (x - p[2][X])*(x - p[3][X])/(p[1][X] - p[2][X])/(p[1][X] - p[3][X])*p[1][Y] +
-          (x - p[1][X])*(x - p[3][X])/(p[2][X] - p[1][X])/(p[2][X] - p[3][X])*p[2][Y] +
-          (x - p[1][X])*(x - p[2][X])/(p[3][X] - p[1][X])/(p[3][X] - p[2][X])*p[3][Y]
-end function
-function getPoints(integer n)
-    sequence pts = {}
-    atom {dx,pt,cnt} := {(p[2][X] - p[1][X])/n, p[1][X], n}
-    for j=1 to 2 do
-        for i=0 to cnt do
-            atom x := pt + dx*i;
-            pts = append(pts,{x,lagrange(x)});
-        end for
-        {dx,pt,cnt} = {(p[3][X] - p[2][X])/n, p[2][X], n+1};
-    end for
-    return pts
-end function
-procedure draw_cross(sequence xy)
-    integer {x,y} = xy
-    cdCanvasLine(cddbuffer, x-3, y, x+3, y)
-    cdCanvasLine(cddbuffer, x, y-3, x, y+3)
-end procedure
-function redraw_cb(Ihandle /*ih*/, integer /*posx*/, integer /*posy*/)
-    cdCanvasActivate(cddbuffer)
-    cdCanvasSetForeground(cddbuffer, CD_BLUE)
-    cdCanvasBegin(cddbuffer,CD_OPEN_LINES)
-    atom {x,y} = {p[1][X], p[1][Y]}; -- curve starting point
-    cdCanvasVertex(cddbuffer, x, y)
-    sequence pts = getPoints(50)
-    for i=1 to length(pts) do
-        {x,y} = pts[i]
-        cdCanvasVertex(cddbuffer, x, y)
-    end for
-    cdCanvasEnd(cddbuffer)
-    cdCanvasSetForeground(cddbuffer, CD_RED)
-    for i=1 to length(p) do draw_cross(p[i]) end for
-    cdCanvasFlush(cddbuffer)
-    return IUP_DEFAULT
-end function
-function map_cb(Ihandle ih)
-    cdcanvas = cdCreateCanvas(CD_IUP, ih)
-    cddbuffer = cdCreateCanvas(CD_DBUFFER, cdcanvas)
-    cdCanvasSetBackground(cddbuffer, CD_WHITE)
-    return IUP_DEFAULT
-end function
-procedure main()
-    IupOpen()
-    canvas = IupCanvas(NULL)
-    IupSetAttribute(canvas, "RASTERSIZE", "220x220")
-    IupSetCallback(canvas, "MAP_CB", Icallback("map_cb"))
-    dlg = IupDialog(canvas,"DIALOGFRAME=YES")
-    IupSetAttribute(dlg, "TITLE", "Quadratic curve")
-    IupSetCallback(canvas, "ACTION", Icallback("redraw_cb"))
-    IupCloseOnEscape(dlg)
-    IupMap(dlg)
-    IupSetAttribute(canvas, "RASTERSIZE", NULL)
-    IupShowXY(dlg,IUP_CENTER,IUP_CENTER)
-    IupMainLoop()
-    IupClose()
-end procedure
-main()</lang>
 =={{header|zkl}}==