PolylineEncoder = function(numLevels, zoomFactor, verySmall, forceEndpoints) { var i; if(!numLevels) { numLevels = 18;}
if(!zoomFactor) { zoomFactor = 2;}
if(!verySmall) { verySmall = 0.00001;}
if(!forceEndpoints) { forceEndpoints = true;}
this.numLevels = numLevels; this.zoomFactor = zoomFactor; this.verySmall = verySmall; this.forceEndpoints = forceEndpoints; this.zoomLevelBreaks = new Array(numLevels); for(i = 0; i < numLevels; i++) { this.zoomLevelBreaks[i] = verySmall*Math.pow(zoomFactor, numLevels-i-1);}
}
PolylineEncoder.prototype.dpEncode = function(points) { var absMaxDist = 0; var stack = []; var dists = new Array(points.length); var maxDist, maxLoc, temp, first, last, current; var i, encodedPoints, encodedLevels; var segmentLength; if(points.length > 2) { stack.push([0, points.length-1]); while(stack.length > 0) { current = stack.pop(); maxDist = 0; segmentLength = Math.pow(points[current[1]].lat()-points[current[0]].lat(),2) + Math.pow(points[current[1]].lng()-points[current[0]].lng(),2); for(i = current[0]+1; i < current[1]; i++) { temp = this.distance(points[i], points[current[0]], points[current[1]], segmentLength); if(temp > maxDist) { maxDist = temp; maxLoc = i; if(maxDist > absMaxDist) { absMaxDist = maxDist;}
}
}
if(maxDist > this.verySmall) { dists[maxLoc] = maxDist; stack.push([current[0], maxLoc]); stack.push([maxLoc, current[1]]);}
}
}
encodedPoints = this.createEncodings(points, dists); encodedLevels = this.encodeLevels(points, dists, absMaxDist); return { encodedPoints: encodedPoints, encodedLevels: encodedLevels, encodedPointsLiteral: encodedPoints.replace(/\\/g,"\\\\")
}
}
PolylineEncoder.prototype.dpEncodeToJSON = function(points, color, weight, opacity) { var result; if(!opacity) { opacity = 0.9;}
if(!weight) { weight = 3;}
if(!color) { color = "#0000ff";}
result = this.dpEncode(points); return { color: color, weight: weight, opacity: opacity, points: result.encodedPoints, levels: result.encodedLevels, numLevels: this.numLevels, zoomFactor: this.zoomFactor
}
}
PolylineEncoder.prototype.dpEncodeToGPolyline = function(points, color, weight, opacity) { if(!opacity) { opacity = 0.9;}
if(!weight) { weight = 3;}
if(!color) { color = "#0000ff";}
return new GPolyline.fromEncoded( this.dpEncodeToJSON(points, color, weight, opacity));}
PolylineEncoder.prototype.dpEncodeToGPolygon = function(pointsArray, boundaryColor, boundaryWeight, boundaryOpacity, fillColor, fillOpacity, fill, outline) { var i, boundaries; if(!boundaryColor) { boundaryColor = "#0000ff";}
if(!boundaryWeight) { boundaryWeight = 3;}
if(!boundaryOpacity) { boundaryOpacity = 0.9;}
if(!fillColor) { fillColor = boundaryColor;}
if(!fillOpacity) { fillOpacity = boundaryOpacity/3;}
if(fill==undefined) { fill = true;}
if(outline==undefined) { outline = true;}
boundaries = new Array(0); for(i=0; i<pointsArray.length; i++) { boundaries.push(this.dpEncodeToJSON(pointsArray[i], boundaryColor, boundaryWeight, boundaryOpacity));}
return new GPolygon.fromEncoded({ polylines: boundaries, color: fillColor, opacity: fillOpacity, fill: fill, outline: outline
});}
PolylineEncoder.prototype.distance = function(p0, p1, p2, segLength) { var u, out; if(p1.lat() === p2.lat() && p1.lng() === p2.lng()) { out = Math.sqrt(Math.pow(p2.lat()-p0.lat(),2) + Math.pow(p2.lng()-p0.lng(),2));}
else { u = ((p0.lat()-p1.lat())*(p2.lat()-p1.lat())+(p0.lng()-p1.lng())*(p2.lng()-p1.lng()))/
segLength; if(u <= 0) { out = Math.sqrt(Math.pow(p0.lat() - p1.lat(),2) + Math.pow(p0.lng() - p1.lng(),2));}
if(u >= 1) { out = Math.sqrt(Math.pow(p0.lat() - p2.lat(),2) + Math.pow(p0.lng() - p2.lng(),2));}
if(0 < u && u < 1) { out = Math.sqrt(Math.pow(p0.lat()-p1.lat()-u*(p2.lat()-p1.lat()),2) + Math.pow(p0.lng()-p1.lng()-u*(p2.lng()-p1.lng()),2));}
}
return out;}
PolylineEncoder.prototype.createEncodings = function(points, dists) { var i, dlat, dlng; var plat = 0; var plng = 0; var encoded_points = ""; for(i = 0; i < points.length; i++) { if(dists[i] != undefined || i == 0 || i == points.length-1) { var point = points[i]; var lat = point.lat(); var lng = point.lng(); var late5 = Math.floor(lat * 1e5); var lnge5 = Math.floor(lng * 1e5); dlat = late5 - plat; dlng = lnge5 - plng; plat = late5; plng = lnge5; encoded_points += this.encodeSignedNumber(dlat) + this.encodeSignedNumber(dlng);}
}
return encoded_points;}
PolylineEncoder.prototype.computeLevel = function(dd) { var lev; if(dd > this.verySmall) { lev=0; while(dd < this.zoomLevelBreaks[lev]) { lev++;}
return lev;}
}
PolylineEncoder.prototype.encodeLevels = function(points, dists, absMaxDist) { var i; var encoded_levels = ""; if(this.forceEndpoints) { encoded_levels += this.encodeNumber(this.numLevels-1)
} else { encoded_levels += this.encodeNumber( this.numLevels-this.computeLevel(absMaxDist)-1)
}
for(i=1; i < points.length-1; i++) { if(dists[i] != undefined) { encoded_levels += this.encodeNumber( this.numLevels-this.computeLevel(dists[i])-1);}
}
if(this.forceEndpoints) { encoded_levels += this.encodeNumber(this.numLevels-1)
} else { encoded_levels += this.encodeNumber( this.numLevels-this.computeLevel(absMaxDist)-1)
}
return encoded_levels;}
PolylineEncoder.prototype.encodeNumber = function(num) { var encodeString = ""; var nextValue, finalValue; while (num >= 0x20) { nextValue = (0x20 | (num & 0x1f)) + 63; encodeString += (String.fromCharCode(nextValue)); num >>= 5;}
finalValue = num + 63; encodeString += (String.fromCharCode(finalValue)); return encodeString;}
PolylineEncoder.prototype.encodeSignedNumber = function(num) { var sgn_num = num << 1; if (num < 0) { sgn_num = ~(sgn_num);}
return(this.encodeNumber(sgn_num));}
PolylineEncoder.latLng = function(y, x) { this.y = y; this.x = x;}
PolylineEncoder.latLng.prototype.lat = function() { return this.y;}
PolylineEncoder.latLng.prototype.lng = function() { return this.x;}
PolylineEncoder.pointsToLatLngs = function(points) { var i, latLngs; latLngs = new Array(0); for(i=0; i<points.length; i++) { latLngs.push(new PolylineEncoder.latLng(points[i][0], points[i][1]));}
return latLngs;}
PolylineEncoder.pointsToGLatLngs = function(points) { var i, gLatLngs; gLatLngs = new Array(0); for(i=0; i<points.length; i++) { gLatLngs.push(new GLatLng(points[i][0], points[i][1]));}
return gLatLngs;}