From 9b34b8cfd03519c0b27f68f25bd8fd7d3e361d7a Mon Sep 17 00:00:00 2001
From: Eyck Jentzsch <eyck@minres.com>
Date: Tue, 21 Jun 2016 17:30:36 +0200
Subject: [PATCH] Added support for  gcode arc commands (G2/G3)  in IJ notation

---
 src/octoprint/static/gcodeviewer/js/Worker.js | 21 ++++++++++++++++++-
 .../static/gcodeviewer/js/renderer.js         | 14 ++++++++++++-
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/src/octoprint/static/gcodeviewer/js/Worker.js b/src/octoprint/static/gcodeviewer/js/Worker.js
index e699cb28..4f3cf4ce 100644
--- a/src/octoprint/static/gcodeviewer/js/Worker.js
+++ b/src/octoprint/static/gcodeviewer/js/Worker.js
@@ -229,6 +229,7 @@ var doParse = function () {
 
     var layer = 0;
     var x, y, z = 0;
+    var center_i, center_j, direction;
     var prevX = 0, prevY = 0, prevZ = 0;
     var f, lastF = 4000;
     var extrude = false, extrudeRelative = false, retract = 0;
@@ -251,6 +252,9 @@ var doParse = function () {
         y = undefined;
         z = undefined;
         retract = 0;
+        center_i = undefined;
+        center_j = undefined;
+        direction = undefined;
 
         var line = gcode[i].line;
         var percentage = gcode[i].percentage;
@@ -263,7 +267,7 @@ var doParse = function () {
 
         var log = false;
 
-        if (/^(?:G0|G1)\s/i.test(line)) {
+        if (/^(?:G0|G1|G2|G3)\s/i.test(line)) {
             var args = line.split(/\s/);
 
             for (var j = 0; j < args.length; j++) {
@@ -330,6 +334,18 @@ var doParse = function () {
                         numSlice = parseFloat(args[j].slice(1));
                         lastF = numSlice;
                         break;
+                    case 'i':
+                        center_i = Number(args[j].slice(1));
+                        break;
+                    case 'j':
+                        center_j = Number(args[j].slice(1));
+                        break;
+                    case 'g':
+                        if(args[j].charAt(1).toLowerCase()=='2')
+                            direction=1;
+                        if(args[j].charAt(1).toLowerCase()=='3')
+                            direction=-1;
+                        break;
                 }
             }
 
@@ -487,6 +503,9 @@ var doParse = function () {
                 x: x,
                 y: y,
                 z: z,
+                i: center_i,
+                j: center_j,
+                direction: direction,
                 extrude: extrude,
                 retract: retract,
                 noMove: !move,
diff --git a/src/octoprint/static/gcodeviewer/js/renderer.js b/src/octoprint/static/gcodeviewer/js/renderer.js
index 32f2195a..779354b5 100644
--- a/src/octoprint/static/gcodeviewer/js/renderer.js
+++ b/src/octoprint/static/gcodeviewer/js/renderer.js
@@ -490,7 +490,19 @@ GCODE.renderer = (function(){
                     ctx.lineWidth = renderOptions['extrusionWidth'];
                     ctx.beginPath();
                     ctx.moveTo(prevX, prevY);
-                    ctx.lineTo(x*zoomFactor,y*zoomFactor);
+                    if(cmd.direction !== undefined && cmd.direction != 0){
+                        var cmd = cmds[i];
+                        var di = cmd.i*zoomFactor;
+                        var dj = -1*cmd.j*zoomFactor; // Y-coordinate is inverted
+                        var centerX = prevX+di;
+                        var centerY = prevY+dj;
+                        var startAngle = Math.atan2(prevY-centerY, prevX - centerX);
+                        var endAngle = Math.atan2(y*zoomFactor-centerY, x*zoomFactor - centerX);
+                        var radius=Math.sqrt(di*di+dj*dj);
+                        ctx.arc(centerX,centerY,radius,startAngle,endAngle,cmd.direction<0); // Y-coordinate is inverted so direction is also inverted
+                    } else {
+                        ctx.lineTo(x*zoomFactor,y*zoomFactor);
+                    }
                     ctx.stroke();
                 } else {
                     // we were previously retracting, now we are restarting => draw dot if configured to do so