From bd06a25f7f7ea305c31e24184c1efdca91c5c5ca Mon Sep 17 00:00:00 2001
From: Val Erastov <xibyte@gmail.com>
Date: Thu, 10 Mar 2016 23:47:40 -0800
Subject: [PATCH] Min length of line experiment

---
 web/app/sketcher/canvas.js             | 29 +++++++++++++++---
 web/app/sketcher/constr/constraints.js | 41 ++++++++++++++++++++++++++
 web/app/sketcher/parametric.js         | 20 +++++++++++++
 3 files changed, 86 insertions(+), 4 deletions(-)

diff --git a/web/app/sketcher/canvas.js b/web/app/sketcher/canvas.js
index 272a43e8..cf381119 100644
--- a/web/app/sketcher/canvas.js
+++ b/web/app/sketcher/canvas.js
@@ -621,9 +621,14 @@ TCAD.TWO.Segment = function(a, b) {
 TCAD.TWO.utils.extend(TCAD.TWO.Segment, TCAD.TWO.SketchObject);
 
 TCAD.TWO.Segment.prototype._class = 'TCAD.TWO.Segment';
+TCAD.TWO.Segment.MIN_LENGTH = 0.1; // 0.08; // if length < 0.08 canvas doesn't even draw a line
 
 TCAD.TWO.Segment.prototype.validate = function() {
-  return TCAD.math.distanceAB(this.a, this.b) > TCAD.TOLERANCE;
+  return TCAD.math.distanceAB(this.a, this.b) > TCAD.TWO.Segment.MIN_LENGTH;
+};
+
+TCAD.TWO.Segment.prototype.addFixingGeomConstraints = function(constrs) {
+  constrs.push(new TCAD.TWO.Constraints.MinLength(this.a, this.b, TCAD.TWO.Segment.MIN_LENGTH));
 };
 
 TCAD.TWO.Segment.prototype.collectParams = function(params) {
@@ -925,7 +930,7 @@ TCAD.TWO.DragTool.prototype.mousedown = function(e) {
   this.origin.x = e.offsetX;
   this.origin.y = e.offsetY;
   this.viewer.screenToModel2(e.offsetX, e.offsetY, this._point);
-  this.prepareSolver();
+  this.prepareSolver([]);
 };
 
 TCAD.TWO.DragTool.prototype.mouseup = function(e) {
@@ -945,6 +950,22 @@ TCAD.TWO.DragTool.prototype.mousewheel = function(e) {
 TCAD.TWO.DragTool.prototype.solveRequest = function(rough) {
   this.solver.solve(rough, 1);
   this.solver.sync();
+  if (false) {
+    var fixingConstrs = [];
+    this.viewer.accept(function(obj) {
+      if (obj._class === 'TCAD.TWO.Segment') {
+        if (!obj.validate()) {
+          obj.addFixingGeomConstraints(fixingConstrs);
+        }
+      }
+      return true;
+    });
+    if (fixingConstrs.length !== 0) {
+      this.prepareSolver(fixingConstrs);
+      this.solver.solve(rough, 1);
+      this.solver.sync();
+    }
+  }
 };
 
 TCAD.TWO.DragTool.prototype.getParamsToLock = function() {
@@ -959,7 +980,7 @@ TCAD.TWO.DragTool.prototype.getParamsToLock = function() {
   return params;
 };
 
-TCAD.TWO.DragTool.prototype.prepareSolver = function() {
+TCAD.TWO.DragTool.prototype.prepareSolver = function(extraConstraints) {
   var locked = this.getParamsToLock();
   this.lockedShifts = [];
   this.lockedValues = [];
@@ -967,7 +988,7 @@ TCAD.TWO.DragTool.prototype.prepareSolver = function() {
     this.lockedShifts[i] = this._point.x - locked[i].get();
     this.lockedShifts[i + 1] = this._point.y - locked[i + 1].get();
   }
-  this.solver = this.viewer.parametricManager.prepare(locked);
+  this.solver = this.viewer.parametricManager.prepare(locked, extraConstraints);
   //this.enableRecording();
 };
 
diff --git a/web/app/sketcher/constr/constraints.js b/web/app/sketcher/constr/constraints.js
index 08dbd69e..f3ff76b6 100644
--- a/web/app/sketcher/constr/constraints.js
+++ b/web/app/sketcher/constr/constraints.js
@@ -6,6 +6,8 @@ TCAD.constraints.create = function(name, params, values) {
       return new TCAD.constraints.Equal(params);
     case "equalsTo":
       return new TCAD.constraints.EqualsTo(params, values[0]);
+    case "MinLength":
+      return new TCAD.constraints.MinLength(params, values[0]);
     case "perpendicular":
       return new TCAD.constraints.Perpendicular(params);
     case "parallel":
@@ -42,6 +44,45 @@ TCAD.constraints.Equal = function(params) {
   }
 };
 
+
+TCAD.constraints.MinLength = function(params, distance) {
+  
+  this.params = params;
+  this.distance = distance;
+
+  var p1x = 0;
+  var p1y = 1;
+  var p2x = 2;
+  var p2y = 3;
+
+  this.error = function() {
+    var dx = params[p1x].get() - params[p2x].get();
+    var dy = params[p1y].get() - params[p2y].get();
+    var d = Math.sqrt(dx * dx + dy * dy);
+    return d < this.distance ? (d - this.distance) : 0;
+  };
+
+  this.gradient = function(out) {
+    var dx = params[p1x].get() - params[p2x].get();
+    var dy = params[p1y].get() - params[p2y].get();
+    var d = Math.sqrt(dx * dx + dy * dy);
+    if (d == 0) {
+      d = 0.000001;
+    }
+    if (d >= this.distance) {
+      out[p1x] = 0;
+      out[p1y] = 0;
+      out[p2x] = 0;
+      out[p2y] = 0;
+    }
+    out[p1x] = dx / d;
+    out[p1y] = dy / d;
+    out[p2x] = -dx / d;
+    out[p2y] = -dy / d;
+  }
+};
+
+
 /** @constructor */
 TCAD.constraints.ConstantWrapper = function(constr, mask) {
 
diff --git a/web/app/sketcher/parametric.js b/web/app/sketcher/parametric.js
index 903b1d4c..8d751b71 100644
--- a/web/app/sketcher/parametric.js
+++ b/web/app/sketcher/parametric.js
@@ -877,6 +877,26 @@ TCAD.TWO.Constraints.P2LDistance.prototype.SettableFields = {'d' : "Enter the di
 
 // ------------------------------------------------------------------------------------------------------------------ //
 
+/** @constructor */
+TCAD.TWO.Constraints.MinLength = function(a, b, min) {
+  this.a = a;
+  this.b = b;
+  this.min = min;
+  this.aux = true;
+};
+
+TCAD.TWO.Constraints.MinLength.prototype.NAME = 'MinLength';
+TCAD.TWO.Constraints.MinLength.prototype.UI_NAME = 'MinLength';
+
+TCAD.TWO.Constraints.MinLength.prototype.getSolveData = function() {
+  var params = [];
+  this.a.collectParams(params);
+  this.b.collectParams(params);
+  return [[this.NAME, params, [this.min]]];
+};
+
+// ------------------------------------------------------------------------------------------------------------------ //
+
 /** @constructor */
 TCAD.TWO.Constraints.P2LDistanceV = function(p, l, d) {
   this.p = p;