fairphone-case: Button: fix plan to not leave dangling bits of ledge

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/fairphone-case.scad b/fairphone-case.scad
index 0b73f657e2654df6e58b460341ae5a69d2bda72f..26b6c06e9539e81b1294463347bf5769fa7e7870 100644 (file)
--- a/fairphone-case.scad
+++ b/fairphone-case.scad
@@ -150,43 +150,45 @@ module ButtonCoverProfile(){
 }
 
 module ButtonPlan(l, deep, cut){
-  bigger =
-    (deep ? lid_buttoncover_overlap : 0) +
-    (cut  ? 0 : -lid_buttoncover_gap);
-
-  d_D1_y =
+  epsilon =
     (cut  ? 0 : lid_buttoncover_gap);
 
+  delta =
+    (deep ? lid_buttoncover_overlap : 0);
+
   C = [0,0]; // by definition
   T = [ 0, epp4[1] ];
   G = T + [0,10];
+
   B0 = C + [0,-1] * button_cutout_depth;
   r0 = 0.5 * (T[1] - B0[1]);
   A = [  -(l + button_l_fudge)/2 + r0, 0.5 * (T[1] + B0[1]) ];
-  r1 = r0 + bigger;
-  // | D1 - A | = r1 * 2
-  // D1_y = T_y - r1 + d_D1_y
-  // =>    4 * r1^2   =  (r1-r0 + d_D1_y)^2 + (D1_x - A_x)^2
-  // =>    D1_x =  A_x + v/~ [  4 * r1^2   -   (r1-r0 + d_D1_y)^2 ]
-  D1  = [ A[0] - sqrt( 4*r1*r1 - pow(bigger + d_D1_y, 2) ),
-         T[1] - r1 + d_D1_y ];
-  E1  = 0.5 * (D1 + A);
-  F1  = D1 + [0,10];
+  H = A + [0,-1] * delta;
+
+  D = A + [-2,0] * r0;
+  F = D + [0,10];
+
+  E0 = 0.5 * (D + A);
+  E1 = E0 + [1,0] * epsilon;
+
+  I0 = [ E0[0], H[1] ];
+  I1 = [ E1[0], H[1] ];
 
   hull(){
     for (m=[0,1]) mirror([m,0])
-      circleat(A, r1);
+      circleat(H, r0 - epsilon);
   }
   for (m=[0,1]) mirror([m,0]) {
     difference(){
       polygon([ E1,
-               A,
+               I1,
+               H,
                B0,
                G,
-               F1,
-               D1
+               F,
+               D
                ]);
-      circleat(D1, r1);
+      circleat(D, r0 + epsilon);
     }
   }
 }
@@ -401,9 +403,8 @@ module Keeper(){ ////toplevel
     OneKeeper();
 }
 
-module ButtonPlanForDemo(colour, z, deep, cut){
-  color(colour)
-    translate([0,0,z])
+module ButtonPlanForDemo(z, deep, cut){
+  translate([0,0,z])
     ButtonPlan(8, deep, cut);
 }
 
@@ -427,9 +428,9 @@ module DemoProfiles(){ ////toplevel
   }
 
   translate([-20,0]) {
-    ButtonPlanForDemo("grey", -1, 0,1);
-    ButtonPlanForDemo("blue", -2, 1,0);
-    ButtonPlanForDemo("red",  -3, 1,1);
+    color("black") ButtonPlanForDemo(-2, 0,1);
+    color("red" )  ButtonPlanForDemo(-4, 1,1);
+    color("blue")  ButtonPlanForDemo(-6, 1,0);
   }
 }