Added curving

demo/demo.cpp

@@ -18,14 +18,31 @@ void rect(Turtle& t, float width, float height) {
   t.right(90);
 }
 
+void softrect(Turtle& t, float width, float height) {
+  t.forward(width);
+  t.rcurve(90, 10);
+  t.forward(height);
+  t.rcurve(90, 10);
+  t.forward(width);
+  t.rcurve(90, 10);
+  t.forward(height);
+  t.rcurve(90, 10);
+}
 
 void meetTurtle() {
-  Turtle t;
-  t.satinon(0.3);
-  t.pendown();  
-  rect(t, 20, 30);
-  t.end();
-  t.save("demo.dst");
+  Turtle rt;
+  rt.satinon(0.3);
+  rt.pendown();  
+  rect(rt, 20, 30);
+  rt.end();
+  rt.save("demo_rect.dst");
+
+  Turtle srt;
+  srt.satinon(0.3);
+  srt.pendown();  
+  softrect(srt, 20, 30);
+  srt.end();
+  srt.save("demo_softrect.dst");
 }
 
 int main() {

src/turtle.cpp

@@ -122,7 +122,7 @@ void Turtle::setdir(const float x, const float y) {
     setdir(Point(x, y));
 }
 
-/** Turns the Turle `degreesccw` degrees. */
+/** Turns the Turtle `degreesccw` degrees. */
 void Turtle::turn(const float degreesccw) {
     float radcw = -degreesccw / 180.0 * 3.141592653589;
     dir_ = Point(cos(radcw) * dir_.x_ - sin(radcw) * dir_.y_,
@@ -207,6 +207,30 @@ void Turtle::backward(const float dist) {
     move(dir_ * dist * -1);
 }
 
+/** Rightward curve
+ * Curves the turtle to the right along a calculated path 
+ */
+void Turtle::rcurve(int degree, int len) {
+  //len is basically the step count 
+  float turnGradient = degree / len; 
+  for (int i=0;i<len;i++) {
+    turn(turnGradient);
+    move(dir_ * 1);
+  }
+}
+
+/** Leftward curve
+ * Curves the turtle to the right along a calculated path 
+ */
+void Turtle::lcurve(int degree, int len) {
+  //len is basically the step count 
+  float turnGradient = degree / len; 
+  for (int i=0;i<len;i++) {
+    turn(-turnGradient);
+    move(dir_ * 1);
+  }
+}
+
 // Functions for drawing text
 
 /** Draws the text `message`.

src/turtle.hpp

@@ -25,6 +25,8 @@ class Turtle {
     void turn(const float degreesccw);
     void right(float degreesccw);
     void left(float degreesccw);
+    void rcurve(int degree, int len);
+    void lcurve(int degree, int len);
 
     void move(const Point& delta);
     void move(const float x, const float y);