From: W. Trevor King <wking@drexel.edu>
Date: Wed, 11 Apr 2012 20:27:49 +0000 (-0400)
Subject: Simplify Angle labeling to respect Label attributes in Mechanics.asy.
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=7eb6f5a8e176aee8fb04de17cd9c6ec8b81a301e;p=course.git

Simplify Angle labeling to respect Label attributes in Mechanics.asy.
---

diff --git a/asymptote/Mechanics-test.asy b/asymptote/Mechanics-test.asy
index 9dc92ec..42897d7 100644
--- a/asymptote/Mechanics-test.asy
+++ b/asymptote/Mechanics-test.asy
@@ -46,14 +46,18 @@ Mass a = Mass(center=(0,0));
 Mass b = Mass(center=(2u,1u), Label("$m_b$", align=N));
 Mass c = Mass(center=(1u,-2u), Label("$m_c$", align=E));
 Mass ms[] = {a,b, c};
-Distance dab = Distance(a.center(), b.center(), scale=u, L="$r_{ab}$");
+Distance dab = Distance(b.center(), a.center(), scale=u,
+    L=Label("$r_{ab}$", embed=Shift));
 Distance dac = Distance(a.center(), c.center(), scale=u, L="$r_{ac}$");
 Distance ds[] = {dab, dac};
 Angle bac1 = Angle(
     b.center(), a.center(), c.center(), radius=.7u, fill=red, L="$\theta_T'$");
 Angle bac2 = Angle(
     b.center(), a.center(), c.center(), radius=-.5u, L="$\theta_T$");
-Angle as[] = {bac1, bac2};
+Angle bac3 = Angle(
+    b.center(), a.center(), c.center(), radius=1.5u,
+    L=Label("$\theta_T''$", position=Relative(0.3)));
+Angle as[] = {bac1, bac2, bac3};
 
 Vector vs[];
 
diff --git a/asymptote/Mechanics.asy b/asymptote/Mechanics.asy
index 4c925fa..96e1a9b 100644
--- a/asymptote/Mechanics.asy
+++ b/asymptote/Mechanics.asy
@@ -38,7 +38,6 @@ struct LabeledCircle {
   }
 
   void draw_label(picture pic=currentpicture, Label L=null) {
-    picture picL;
     align a;
     if (L == null) {
       L = this.label;
@@ -322,7 +321,7 @@ struct Distance {
   real offset;
   real scale;
   pen outline;
-  Label L;
+  Label label;
   
   void operator init(pair pFrom=(0,0), pair pTo=(5mm,0), real offset=0, real scale=5mm, pen outline=currentpen, Label L="") {
     this.pFrom = pFrom;
@@ -330,30 +329,19 @@ struct Distance {
     this.offset = offset;
     this.scale = scale;
     this.outline = outline;
-    this.L = L;
+    this.label = L;
   }
-  
-  void draw(picture pic=currentpicture, bool rotateLabel=true,
-            real labelangle=90, real labeloffset=-1) {
-    picture picF;
-    pair pDiff = pTo - pFrom;
-    if (labeloffset == -1) {
-      picture picL;
-      label(picL, L);
-      pair pLabelSize = 1.2 * (max(picL)-min(picL));
-      labeloffset = pLabelSize.y/2;
+
+  void draw(picture pic=currentpicture) {
+    pair o = this.offset*unit(rotate(-90)*(this.pTo - this.pFrom));
+    path p = (this.pFrom+o) -- (this.pTo+o);
+    draw(pic, p, outline, Arrows);
+    embed e = this.label.embed;
+    if (this.label.embed == Rotate) {
+      this.label.embed = Rotate(this.pFrom - this.pTo);
     }
-    path p = (0,0)--pDiff;
-    pair label_rotate=pDiff;
-    if (rotateLabel == false)
-      label_rotate=(1,0);
-    draw(picF, p, outline, Arrows);
-    label(pic = picF,
-          L = rotate(degrees(label_rotate)) * L,
-          position =  pDiff/2
-            + unit(rotate(labelangle)*pDiff) * labeloffset);
-    //label(pic=picF, L = rotate(degrees(label_rotate)) format("%g", pDiff/scale), position = TODO);
-    add(pic, picF, pFrom+offset*unit(rotate(-90)*pDiff));
+    label(pic=pic, L=this.label, g=p);
+    this.label.embed = e;
   }
 }
 
@@ -364,7 +352,7 @@ struct Angle {
   real radius; // radius < 0 for exterior angles.
   pen outline;
   pen fill;
-  Label L;
+  Label label;
 
   void operator init(pair B, pair A, pair C, real radius=5mm, pen outline=currentpen, pen fill=invisible, Label L="") {
     this.B = B;
@@ -373,17 +361,13 @@ struct Angle {
     this.radius = radius;
     this.outline = outline;
     this.fill = fill;
-    this.L = L;
+    this.label = L;
   }
   
-  void draw(picture pic=currentpicture, bool rotateLabel=false,
-            real labelOffsetAdjustment=0) {
+  void draw(picture pic=currentpicture) {
     picture picF;
-    picture picL;
     bool direction;
-    label(picL, L);
     
-    pair pLabelSize = 1.2 * (max(picL)-min(picL));
     real ccw_angle = degrees(C-A)-degrees(B-A);
     bool direction = CCW;
     if (ccw_angle < 0) ccw_angle += 360.0;
@@ -392,23 +376,15 @@ struct Angle {
     if (radius < 0)
       direction = !direction;
     path p = arc((0,0), fabs(radius), degrees(B-A), degrees(C-A), direction);
-    real t = reltime(p, 0.5);
-    pair P = midpoint(p);
-    pair tangent = dir(p, t);
-    if (direction == CW) tangent *= -1.0;
-    
-    pair label_rotate = tangent;
-    if (rotateLabel == false)
-      label_rotate = (1,0);
-    
     if (this.fill != invisible) {
       path pcycle = (0,0) -- p -- cycle;
       fill(picF, pcycle, this.fill);
     }
     draw(picF, p, this.outline);
-    label(pic = picF,
-          L = rotate(degrees(label_rotate)) * L,
-          position = P + unit(P) * (pLabelSize.y / 2 + labelOffsetAdjustment));
+    if (direction == CW) {
+      p = reverse(p);
+    }
+    label(pic=picF, L=this.label, g=p);
     add(pic, picF, A);
   }
 }
@@ -601,7 +577,7 @@ struct Pendulum {
 Pendulum makePendulum(pair pivot=(0,0), Mass mass=Mass(), real length=15mm, real angleDeg=0, Label angleL="", Label stringL="") {
   mass.set_center(pivot + length*dir(angleDeg-90));
   Pendulum p = Pendulum(pivot=pivot, mass=mass);
-  p.angle.L = angleL;
+  p.angle.label = angleL;
   p.str.L = stringL;
   return p;
 }