Re: Dynamic Text in Manipulate.

*To*: mathgroup at smc.vnet.net*Subject*: [mg112037] Re: Dynamic Text in Manipulate.*From*: "David Park" <djmpark at comcast.net>*Date*: Thu, 26 Aug 2010 06:47:58 -0400 (EDT)

The code below constructs your diagram as a custom dynamic using Presentations. 1) This uses the second argument of Dynamic to call a calcAll routine that calculates all the secondary dynamic variables dependent on u. 2) I don't know how important it is to keep the coordinates rational, but I stayed with that. This required the u = Rationalize[#] (instead of u= #) in the second argument of the Dynamic Slider statement. 3) I calculate the centroid of the triangle using a Presentations routine and then displace the vertex labels outward from the centroid. This is a good method for placing labels on dynamic triangles. 4) There is then only one labeling routine, vertexLabel. 5) I think a Frame plot looks better than an Axes plot. Needs["Presentations`Master`"] DynamicModule[ {u = 0, ptA, ptB, ptC, centroid, vertexLabel, calcAll}, vertexLabel[name_String, pt_] := Module[{x = First[pt], y = Last[pt]}, Text[phrase[name, "{", x, ",", y, "}"], pt + 0.75 Normalize[pt - centroid], {0, 0}]]; calcAll[u_] := (ptA = {2 - u, 8/5 - u (4/5)}; ptB = {4 - u, 11/5 - u (7/10)}; ptC = {23/5 - u, 23/5 - u (7/10)}; centroid = First@triangleCentroid[{ptA, ptB, ptC}]); calcAll[u]; page[ {phrase["u: ", Slider[Dynamic[u, (u = Rationalize[#]; calcAll[u]) &], {0, 2, 1/10}, Appearance -> "Labeled"]], Draw2D[ {PointSize[0.02], Thick, Dynamic@ {Line[{ptA, ptB, ptC, ptA}], Point[{ptA, ptB, ptC}], Directive[FontWeight -> Bold, FontSize -> 13, Black], MapThread[ vertexLabel[#1, #2] &, {{"A", "B", "C"}, {ptA, ptB, ptC}}]}}, Frame -> True, PlotRange -> {{-1.25, 6}, {-1, 6}}, PlotRangePadding -> 0.1, GridLines -> {{0, 1, 2, 13/5, 4, 23/5}, {4/5, 8/5, 11/5, 16/5, 23/5}}, ImageSize -> 300]}, Spacings -> 1 ] ] David Park djmpark at comcast.net http://home.comcast.net/~djmpark/ From: Matthias Bode [mailto:lvsaba at hotmail.com] Hola: The code below shifts a triangle with Manipulate[]. I want the coordinates of the corners A{x;y}, B{x;y}, C{x;y} inside the {;} to change with the shift. Rather than my pedestrian dissecting method Text["A {", {2 - u, 7/5 - u*(4/5)}], Text[Dynamic[2 - u, u], {2.2 - u, 7/5 - u*(4/5)}], Text[";", {2.32 - u, 7/5 - u*(4/5)}], Text[Dynamic[8/5 - u*(4/5), u], {2.45 - u, 7/5 - u*(4/5)}], Text["}", {2.6 - u, 7/5 - u*(4/5)}], in five steps I would like to represent "A{x;y}" in ONE command Text[]. How can this be done? Best regards, MATTHIAS BODE S 17.35775=B0, W 066.14577=B0 gra01 = Plot[x, {x, 0, 5}, AspectRatio -> 1, PlotRange -> {{-0.5, 5.1}, {-0.5, 5}}, AxesLabel -> {x, y}, GridLines -> {{1, 2, 13/5, 4, 23/5}, {4/5, 8/5, 11/5, 16/5, 23/5}}, PlotStyle -> Directive[White]]; Manipulate[Show[{gra01, Graphics[{Directive[PointSize[0.02]], Point[{{2 - u, 8/5 - u*(4/5)}, {4 - u, 11/5 - u*(7/10)}, {23/5 - u, 23/5 - u*(7/10)}}], Directive[Thick], Line[{{2 - u, 8/5 - u*(4/5)}, {4 - u, 11/5 - u*(7/10)}, {23/5 - u, 23/5 - u*(7/10)}, {2 - u, 8/5 - u*(4/5)}}], Directive[Dashed, Thin, Red], Line[{{2, 8/5}, {23/5, 8/5}, {23/5, 23/5}, {2, 23/5}, {2, 8/5}}], Line[{{4, 8/5}, {4, 11/5}}], Line[{{23/5, 11/5}, {4, 11/5}}], Directive[FontWeight -> Bold, FontSize -> 13, Black], Text["A {", {2 - u, 7/5 - u*(4/5)}], Text[Dynamic[2 - u, u], {2.2 - u, 7/5 - u*(4/5)}], Text[";", {2.32 - u, 7/5 - u*(4/5)}], Text[Dynamic[8/5 - u*(4/5), u], {2.45 - u, 7/5 - u*(4/5)}], Text["}", {2.6 - u, 7/5 - u*(4/5)}], Text["B {4; 11/5}", {4, 9/5}], Text["C {23/5; 23/5}", {22/5, 24/5}]}]}], {u, 0, 2, 1/10}]