case.scad: factor out the body dilation and cutout creation

src/case.scad

@@ -25,6 +25,48 @@ module _PhoneBulkLayer(tol=tol)
   }
 }
 
+module _DilatedBody(ButtonStyle) {
+  body = 0;
+  buttons = 1;
+  minkowski() {
+    sphere(r=Thickness);
+    union() {
+      children(body);
+      if (ButtonStyle=="extrude") {
+        children(buttons);
+      };
+    }
+  }
+}
+
+module _PeripheralCutouts(ButtonStyle) {
+  buttons = 0;
+  ports = 1;
+  camera = 2;
+  union() {
+    minkowski() {
+      sphere(r=MarginCameraCut);
+      children(camera);
+    };
+    // restrict these cutouts to just the phone bulk -- don't let them impact the back of the case
+    intersection() {
+      _PhoneBulkLayer();
+      union() {
+        if (ButtonStyle == "cut") {
+          minkowski() {
+            sphere(r=MarginButtonsCut);
+            children(buttons);
+          };
+        };
+        minkowski() {
+          sphere(r=MarginPortsCut);
+          children(ports);
+        };
+      };
+    };
+  };
+};
+
 module _FrontFace(tol=tol) {
   color("thistle")
   difference() {
@@ -75,37 +117,17 @@ module Case(ButtonStyle="extrude")
   color("DarkSlateGray")
   difference() {
     // start by dilating the phone
-    minkowski() {
-      sphere(r=Thickness);
-      union() {
-        children(body);
-        if (ButtonStyle=="extrude") {
-          children(buttons);
-        };
-      }
-    }
+    _DilatedBody(ButtonStyle=ButtonStyle) {
+      children(body);
+      children(buttons);
+    };
     // then subtract away phone and cutouts
     union() {
-      minkowski() {
-        sphere(r=MarginCameraCut);
+      _PeripheralCutouts(ButtonStyle=ButtonStyle) {
+        children(buttons);
+        children(ports);
         children(camera);
       };
-      // restrict these cutouts to just the phone bulk -- don't let them impact the back of the case
-      intersection() {
-        _PhoneBulkLayer();
-        union() {
-          if (ButtonStyle == "cut") {
-            minkowski() {
-              sphere(r=MarginButtonsCut);
-              children(buttons);
-            };
-          };
-          minkowski() {
-            sphere(r=MarginPortsCut);
-            children(ports);
-          };
-        };
-      };
       // subtract the phone
       children(body);
       // subtract the buttons (we want to give them a buffer)