more tests for circle arc

Also document it in the CHANGELOG.

CHANGELOG.md

@@ -1,6 +1,13 @@
 # Squib CHANGELOG
 Squib follows [semantic versioning](http://semver.org).
 
+## v0.14.0 / Unreleased
+
+Features:
+* `circle` method now supports various `arc` options, so you can draw partial circles (#211) by @sparr
+
+Special thanks to @sparr for all of his work!!
+
 ## v0.13.2 / 2017-01-27
 
 Bugs:

samples/shapes/_draw_shapes.rb

@@ -18,7 +18,11 @@ Squib::Deck.new do
   ellipse x: 675, y: 105, width: 65, height: 100,
        stroke_width: 5, stroke_color: :orange, angle: -0.2
 
-  circle x: 600, y: 600, radius: 75,
+  circle x: 450, y: 600, radius: 75,
+         fill_color: :gray, stroke_color: :green, stroke_width: 8.0
+
+  circle x: 600, y: 600, radius: 75, # partial circle
+         arc_start: 1, arc_end: 4, arc_direction: :counter_clockwise,
          fill_color: :gray, stroke_color: :green, stroke_width: 8.0
 
   triangle x1: 50, y1: 50,

spec/data/samples/shapes/_draw_shapes.rb.txt

@@ -618,7 +618,18 @@ cairo: set_dash([[]])
 cairo: stroke([])
 cairo: restore([])
 cairo: save([])
-cairo: arc([600, 600, 75, 0, 6.283185307179586])
+cairo: arc([450, 600, 75, 0, 6.283185307179586])
+cairo: set_source_color(["gray"])
+cairo: fill_preserve([])
+cairo: set_source_color(["green"])
+cairo: set_line_width([8.0])
+cairo: set_line_join([0])
+cairo: set_line_cap([0])
+cairo: set_dash([[]])
+cairo: stroke([])
+cairo: restore([])
+cairo: save([])
+cairo: arc_negative([600, 600, 75, 1, 4])
 cairo: set_source_color(["gray"])
 cairo: fill_preserve([])
 cairo: set_source_color(["green"])