qtvcp -hole_circle: add chord length info

In case you want to hand layout a bolt circle

Author: c-morley

lib/python/qtvcp/lib/gcode_utility/hole_circle.py

@@ -224,6 +224,14 @@ def validate(self):
         except:
             self.valid = False
 
+        try:
+            angle = (180/self.num_holes)
+            chord_length = (2 * self.radius) * math.sin(math.radians(angle))
+            self.label_chord_length.setText('{:.3f}'.format(chord_length))
+        except Exception as e:
+            print(e)
+            self.label_chord_length.setText('')
+
         try:
             self.first = float(self.lineEdit_first.text())
             if self.first < 360.0:

lib/python/qtvcp/lib/gcode_utility/hole_circle.ui

@@ -1189,7 +1189,7 @@
         <property name="alignment">
          <set>Qt::AlignCenter</set>
         </property>
-        <layout class="QVBoxLayout" name="layout_gb_preview" stretch="1,0">
+        <layout class="QVBoxLayout" name="layout_gb_preview" stretch="1,0,0">
          <property name="spacing">
           <number>4</number>
          </property>
@@ -1215,6 +1215,24 @@
            </property>
           </layout>
          </item>
+         <item>
+          <layout class="QHBoxLayout" name="horizontalLayout_14">
+           <item>
+            <widget class="QLabel" name="label_2">
+             <property name="text">
+              <string>CHORD LENGTH</string>
+             </property>
+            </widget>
+           </item>
+           <item>
+            <widget class="QLabel" name="label_chord_length">
+             <property name="text">
+              <string/>
+             </property>
+            </widget>
+           </item>
+          </layout>
+         </item>
          <item alignment="Qt::AlignBottom">
           <widget class="QWidget" name="widget_macro" native="true">
            <property name="maximumSize">