Fix incorrect smooth curve ctrl point reflection, update README.md with demo, add compensation for same closepath point, add demo in README

README.md

@@ -8,9 +8,29 @@ Convert any SVG 1.1 path to gcode for a pen plotter, laser engraver, etc.
 - [ ] Biarc interpolation (G2/G3 instead of many G1)
 - [x] Px, pc, in to mm
 - [x] Configurable DPI for px/pc to mm
+- [ ] Sort paths by distance to reduce G0 distances
 
 ## Known bugs & whether fixed
 - [ ] Smooth curves should not use the control point when the previous curve is not of the same type (quadratic -> smooth cubic, cubic -> smooth quadratic)
 - [x] Image coordinates mirrored in the y-axis because SVGs uses upper left corner as (0,0) while GCode uses lower left as (0,0)
 - [x] Close path command connects back to (0.0, 0.0) instead of the last move
 - [ ] Ellipse paths are dubious -- large_arc, sweep may need to be inverted
+
+
+## Demonstration
+
+### Input
+
+```bash
+cargo run --release -- examples/Vanderbilt_Commodores_logo.svg
+```
+
+![Vanderbilt Commodores Logo](examples/Vanderbilt_Commodores_logo.svg)
+
+### Output, rendered at [https://ncviewer.com]()
+
+```bash
+cat output.gcode
+```
+
+![Vanderbilt Commodores Logo Gcode](examples/Vanderbilt_Commodores_logo_gcode.png)

examples/Vanderbilt_Commodores_logo.svg

@@ -0,0 +1,2 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns="http://www.w3.org/2000/svg" xml:space="preserve" height="115.11" viewBox="0 0 117.73047 115.11328" width="117.73" version="1.1" xmlns:cc="http://creativecommons.org/ns#" xmlns:dc="http://purl.org/dc/elements/1.1/"><g transform="matrix(1.25 0 0 -1.25 0 115.11)"><g transform="translate(.83719 .83719)"><path d="m57.975 0.63672-14.858 41.006-35.568-0.01-7.549-0.002 34.061 25.879-17.524 46.24 41.279-24.838 34.465 20.688 6.912 4.15-17.523-46.24 34.06-25.879l-7.5488 0.002-35.568 0.0098-12.07-33.87-2.568-7.1363z" transform="matrix(.8 0 0 -.8 0 91)" fill="#A8996E"/><path d="m57.971 8.5664-12.932 35.686-37.49-0.01 29.615 22.502-15.236 40.206 35.892-21.595 35.981 21.595-15.237-40.206 29.616-22.502-37.491 0.01-12.718-35.686z" transform="matrix(.8 0 0 -.8 0 91)"/><path d="m42.688 46.742v5.2969h2.6855l8.4277 31.018h7.3594l9.0293-31.018h2.5918v-5.2969h-11.158v5.2969h2.918l-6.623 24.178-6.1094-24.178h2.9629v-5.2969h-12.084z" transform="matrix(.8 0 0 -.8 0 91)" fill="#fff"/></g></g></svg>

src/main.rs

@@ -261,7 +261,7 @@ fn svg2program(doc: &svgdom::Document, opts: ProgramOptions, mach: Machine) -> P
                     }
                 }
                 _ => {
-                    info!("Node <{} id=\"{}\" .../> is not supported", id, node.id());
+                    warn!("Node <{} id=\"{}\" .../> is not supported", id, node.id());
                 }
             }
         }

src/turtle.rs

@@ -1,9 +1,12 @@
-use crate::code::{GCode};
+use crate::code::GCode;
 use crate::machine::Machine;
 use lyon_geom::euclid::{Angle, Transform2D};
 use lyon_geom::math::{point, vector, F64Point};
 use lyon_geom::{ArcFlags, CubicBezierSegment, QuadraticBezierSegment, SvgArc};
 
+/// Turtle graphics simulator for paths that outputs the GCode enum representation for each operation.
+/// Handles trasforms, scaling, position offsets, etc.
+/// See https://www.w3.org/TR/SVG/paths.html
 pub struct Turtle {
     curpos: F64Point,
     initpos: F64Point,
@@ -11,7 +14,7 @@ pub struct Turtle {
     scaling: Option<Transform2D<f64>>,
     transtack: Vec<Transform2D<f64>>,
     pub mach: Machine,
-    prev_ctrl: F64Point,
+    prev_ctrl: Option<F64Point>,
 }
 
 impl Default for Turtle {
@@ -23,7 +26,7 @@ impl Default for Turtle {
             scaling: None,
             transtack: vec![],
             mach: Machine::default(),
-            prev_ctrl: point(0.0, 0.0),
+            prev_ctrl: None,
         }
     }
 }
@@ -49,7 +52,7 @@ impl Turtle {
         to = self.curtran.transform_point(&to);
         self.curpos = to;
         self.initpos = to;
-        self.prev_ctrl = to;
+        self.prev_ctrl = None;
 
         vec![
             self.mach.tool_off(),
@@ -69,6 +72,14 @@ impl Turtle {
         Z: Into<Option<f64>>,
         F: Into<Option<f64>>,
     {
+        // See https://www.w3.org/TR/SVG/paths.html#Segment-CompletingClosePath which could result in a G91 G1 X0 Y0
+        if (self.curpos - self.initpos)
+            .abs()
+            .lower_than(&vector(std::f64::EPSILON, std::f64::EPSILON))
+            .all()
+        {
+            return vec![];
+        }
         self.curpos = self.initpos;
         vec![
             self.mach.tool_on(),
@@ -106,7 +117,7 @@ impl Turtle {
         let mut to = point(x, y);
         to = self.curtran.transform_point(&to);
         self.curpos = to;
-        self.prev_ctrl = self.curpos;
+        self.prev_ctrl = None;
 
         vec![
             self.mach.tool_on(),
@@ -144,7 +155,12 @@ impl Turtle {
             last_point.set(point);
         });
         self.curpos = last_point.get();
-        self.prev_ctrl = cbs.ctrl1;
+        // See https://www.w3.org/TR/SVG/paths.html#ReflectedControlPoints
+        self.prev_ctrl = point(
+            2.0 * self.curpos.x - cbs.ctrl2.x,
+            2.0 * self.curpos.y - cbs.ctrl2.y,
+        )
+        .into();
 
         vec![self.mach.tool_on(), self.mach.absolute(), cubic]
             .drain(..)
@@ -209,7 +225,7 @@ impl Turtle {
         F: Into<Option<f64>>,
     {
         let from = self.curpos;
-        let ctrl1 = self.prev_ctrl;
+        let ctrl1 = self.prev_ctrl.unwrap_or(self.curpos);
         let mut ctrl2 = point(x2, y2);
         let mut to = point(x, y);
         if !abs {
@@ -244,7 +260,7 @@ impl Turtle {
         F: Into<Option<f64>>,
     {
         let from = self.curpos;
-        let ctrl = self.prev_ctrl;
+        let ctrl = self.prev_ctrl.unwrap_or(self.curpos);
         let mut to = point(x, y);
         if !abs {
             let invtran = self.curtran.inverse().unwrap();
@@ -345,7 +361,7 @@ impl Turtle {
             last_point.set(point);
         });
         self.curpos = last_point.get();
-        self.prev_ctrl = self.curpos;
+        self.prev_ctrl = None;
 
         vec![self.mach.tool_on(), self.mach.absolute(), ellipse]
             .drain(..)
@@ -385,7 +401,7 @@ impl Turtle {
     pub fn reset(&mut self) {
         self.curpos = point(0.0, 0.0);
         self.curpos = self.curtran.transform_point(&self.curpos);
-        self.prev_ctrl = self.curpos;
+        self.prev_ctrl = None;
         self.initpos = self.curpos;
     }
 }