line-simplify-rdp - npm Package Compare versions

Comparing version 0.3.1 to 0.4.0

index.js

 'use strict';
 
+/** @module line-simplify-rdp */
+
+
 var distanceToLineSegment2 = require('distance-to-line-segment').squaredWithPrecalc;
@@ -39,8 +42,48 @@
 
+function ptsEqual(p1, p2) {
+   return p1.x === p2.x && p1.y === p2.y;
+}
 
-function simplify(points, threshold) {
+
+
+/**
+* Return a simplified version of the polyline or polygon defined by the given 
+* points. Basically what happens is that some points are removed from the line,
+* but only ones that leave the resulting line within a certain distance of the 
+* original.
+* @alias module:line-simplify-rdp
+* @param {array} points - polyline or polygon. Each element of the array must be
+*        an object with at least x and y numeric properties. Neither the array
+*        nor any member will be modified.
+* @param {number} threshold - maximum distance the simplified line can be from 
+*        the original. Should be grater than or equal to zero. Passing zero means
+*        only colinear points will be eliminated; greater values lead to more
+*        aggressive line approximations.
+* @param {boolean} closed - if the passed first point and the last points are
+*        the same, this flag does nothing. Otherwise, if closed is true, the
+*        points will be treated as a polygon with an implied last segment
+*        between the last point and the first point.
+* @returns {array} the simplified points. (This will always be separately
+*        allocated object, not the one passed in, but it *will* contain the
+*        same point objects passed in.)
+*/
+function simplify(points, threshold, closed) {
    var len = points.length;
-   if (len <= 2)
-      return points;
-   
+   threshold = threshold || 0;
+   if (len <= 2 || threshold < 0)
+      return points.slice(0);
+      
+   if (closed) {
+      if (ptsEqual(points[0], points[points.length-1])) {
+         // Treat as unclosed
+         closed = false;  
+      }
+      else {
+         points = points.slice(0);
+         points.push(points[0]);
+         len++;
+      }
+      
+   }
+
    var keepers = [];
@@ -54,2 +97,6 @@ simplifyInternal(points, 0, len-1, threshold, keepers);
    }
+   
+   if (closed) {
+      out.pop();
+   }
    return out;
@@ -56,0 +103,0 @@ }

package.json

 {
   "name": "line-simplify-rdp",
-  "version": "0.3.1",
+  "version": "0.4.0",
   "description": "Simplify lines using the Ramer–Douglas–Peucker algorithm",
@@ -11,2 +11,3 @@ "repository": "https://github.com/scottglz/line-simplify-rdp",
     "validate": "npm ls",
+    "makedocs": "jsdoc2md index.js | cat readme_src/head.md - readme_src/tail.md > README.md",
     "prepublish": "npm run lint && npm run validate && npm run test"
@@ -29,2 +30,3 @@ },
   "devDependencies": {
+    "jsdoc-to-markdown": "^1.3.3",
     "jshint": "^2.9.1",
@@ -31,0 +33,0 @@ "tape": "^4.4.0"

test.js

@@ -7,3 +7,3 @@ 'use strict';
 test("stairstep", function(t) {
-    t.plan(4);
+    t.plan(5);
     var stairstep = [ { x:0, y: 0}];
@@ -19,3 +19,3 @@ for (var i=1; i < 4; i++) {
     
-    for (var i=3; i < 1000; i++) {
+    for (var i=4; i < 1000; i++) {
         stairstep.push({
@@ -26,7 +26,8 @@ x: Math.floor((i)/2),
     }
-     t.deepEquals(simplify(stairstep, 1 ), [stairstep[0],stairstep[999]], "1000 points");
+    t.deepEquals(simplify(stairstep, 1 ), [stairstep[0],stairstep[999]], "1000 points");
+    t.deepEquals(simplify(stairstep, 1, true), [stairstep[0],stairstep[999]], "1000 points, closed");
 });
 
 test("unsimplifiable", function(t) {
-    t.plan(1);
+    t.plan(2);
     var points = [
@@ -40,2 +41,3 @@ { x: 15, y: 60 },
     t.deepEquals(simplify(points, 1), points);
+    t.deepEquals(simplify(points, 1, true), points, "Same results here with closed flag");
 });
@@ -52,6 +54,7 @@
 test("redundant square", function(t) {
-    t.plan(1);
-    var points = expandPts([0,0, 0,1, 0,2, 0,3, 1,3, 2,3, 3,3, 3,2, 3,1, 3,0, 2,0, 1,0, 0,0]);
-    t.deepEquals(simplify(points, 0), expandPts([0,0, 0,3, 3,3, 3,0, 0,0]));
+    t.plan(2);
+    var points = expandPts([0,0, 0,1, 0,2, 0,3, 1,3, 2,3, 3,3, 3,2, 3,1, 3,0, 2,0, 1,0]);
+    t.deepEquals(simplify(points, 0, true), expandPts([0,0, 0,3, 3,3, 3,0]));
+    t.deepEquals(simplify(points, 0), expandPts([0,0, 0,3, 3,3, 3,0, 1,0]), "Different results without closed flag");
 
 });

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Improved metrics

Total package byte prevSize

7384

increased by109.59%

Number of package files

6

increased by20%

Lines of code

128

increased by50.59%

Number of medium quality alerts

1

decreased by-50%

Number of lines in readme file

30

increased byInfinity%

Worsened metrics

Dev dependency count

3

increased by50%

No dependency changes