Reversing a path in Raphael.js - svg

I have two curved paths, both roughly going from left to right, one above the . I need to join them up with straight lines into a closed path.
To do this, I am assuming I need to build the path string of the big closed path. But in order to build the path, I need to reverse the second curve.
How can I reverse a path in Raphael.js? Or is there a better way to do what I want to do?
Thanks.

Can you try using this example?
It creates 2 independent paths running left to right. Then it merges these into a closed path.
Try in JSFiddle.
EDITED:
var paper = Raphael(0, 0, 800, 600);
// Define 2 paths running left to right
var path1 = paper.path("M10 10L200 120 300 80 400 100 450 150")
.attr({stroke: "#00FF00"}),
path2 = paper.path("M10 200L200 220 300 280 400 300 450 250")
.attr({stroke: "#00FF00"}),
closedPath = joinPaths(path1, path2)
.attr({
fill: "#FF0000",
stroke: "#0000FF"
});
// This function is a poc and assumes that
// the paths contain a "M" at the begining
// and that that "M" is replacable by "L" (absolute Line to)
function joinPaths() {
var i,
len = arguments.length,
pathArr =[],
finalPathArr =[];
for (i = 0; i < len; i++) {
pathArr[i] = arguments[i].attr("path");
if (i) {
pathArr[i][0][0] = "L";
pathArr[i].reverse();
if (i === len-1) {
pathArr[i].push("Z");
}
}
finalPathArr = finalPathArr.concat(pathArr[i]);
}
return paper.path(finalPathArr);
}

I needed this functionality recently to fill the area between to curves on a graph. I used the following implementation.
function reversePath(pathString) {
var pathPieces = pathString.match(/[MLHVCSQTA][-0-9.,]*/gi);
var reversed = '';
var skip = true;
var previousPathType;
for (var i = pathPieces.length - 1; i >= 0; i--) {
var pathType = pathPieces[i].substr(0, 1);
var pathValues = pathPieces[i].substr(1);
switch (pathType) {
case 'M':
case 'L':
reversed += (skip ? '' : pathType) + pathValues;
skip = false;
break;
case 'C':
var curvePieces = pathValues.match(/^([-0-9.]*,[-0-9.]*),([-0-9.]*,[-0-9.]*),([-0-9.]*,[-0-9.]*)$/);
reversed += curvePieces[3] + pathType + curvePieces[2] + ',' + curvePieces[1] + ',';
skip = true;
break;
default:
alert('Not implemented: ' + pathType);
break;
}
}
return reversed;
}
And I would call it like so:
var combinedPath = path1 + 'L' + reversePath(path2) + 'Z';

Related

How do I reverse a scanline using the jpeg-js module/node JS buffer?

I've been fiddling around with the jpeg-js module and Node JS Buffer, and attempting to create a small command line program that modifies the decoded JPEG buffer data and creates a pattern of X number of reversed scanlines and X number of normal scanlines before saving a new JPEG. In other words, I'm looking to flip portions of the image, but not the entire image itself (plenty of modules that do such a thing, of course, but not the specific use case I have).
To create the reversed/normal line patterns, I've been reading/writing line by line, and saving a slice of that line to a variable, then starting at the end of scanline and incrementally going down by slices of 4 bytes (the alloc for an RGBA value) until I'm at the beginning of the line. Code for the program:
'use strict';
const fs = require('fs');
const jpeg = require('jpeg-js');
const getPixels = require('get-pixels');
let a = fs.readFileSync('./IMG_0006_2.jpg');
let d = Buffer.allocUnsafe(a.width * a.height * 4);
let c = jpeg.decode(a);
let val = false; // track whether normal or reversed scanlines
let lineWidth = b.width * 4;
let lineCount = 0;
let track = 0;
let track2 = 0;
let track3 = 0;
let curr, currLine; // storage for writing/reading scnalines, respectively
let limit = {
one: Math.floor(Math.random() * 141),
two: Math.floor(Math.random() * 151),
three: Math.floor(Math.random() * 121)
};
if (limit.one < 30) {
limit.one = 30;
}
if (limit.two < 40) {
limit.two = 40;
}
if (limit.two < 20) {
limit.two = 20;
}
let calc = {};
calc.floor = 0;
calc.ceil = 0 + lineWidth;
d.forEach(function(item, i) {
if (i % lineWidth === 0) {
lineCount++;
/* // alternate scanline type, currently disabled to figure out how to succesfully reverse image
if (lineCount > 1 && lineCount % limit.one === 0) {
// val = !val;
}
*/
if (lineCount === 1) {
val = !val; // setting alt scanline check to true initially
} else if (calc.floor + lineWidth < b.data.length - 1) {
calc.floor += lineWidth;
calc.ceil += lineWidth;
}
currLine = c.data.slice(calc.floor, calc.ceil); // current line
track = val ? lineWidth : 0; // tracking variable for reading from scanline
track2 = val ? 4 : 0; // tracking variable for writing from scanline
}
//check if reversed and writing variable has written 4 bytes for RGBA
//if so, set writing source to 4 bytes at end of line and read from there incrementally
if (val && track2 === 4) {
track2 = 0; // reset writing count
curr = currLine.slice(track - 4, track); // store 4 previous bytes as writing source
if (lineCount === 1 && lineWidth - track < 30) console.log(curr); //debug
} else {
curr = currLine; //set normal scanline
}
d[i] = curr[track2];
// check if there is no match between data source and decoded image
if (d[i] !== curr[track2]) {
if (track3 < 50) {
console.log(i);
}
track3++;
}
track2++; //update tracking variable
track = val ? track - 1 : track + 1; //update tracking variable
});
var rawImageData = {
data: d,
width: b.width,
height: b.height
};
console.log(b.data.length);
console.log('errors\t', track3);
var jpegImageData = jpeg.encode(rawImageData, 100);
fs.writeFile('foo2223.jpg', jpegImageData.data);
Alas, the reversed scanline code I've written does not properly. Unfortunately, I've only been able successfully reverse the red channel of my test image (see below left), with the blue and green channels just turning into vague blurs. The color scheme should look something like the right image.
What am I doing wrong here?
For reversed lines, you stored slices of 4 bytes(4 bytes = 1 pixel), then write the first value of the pixel(red) correctly.
But in the next iteration, you overwrite the slice curr with currLine, rest of channels gets wrong values.
if (val && track2 === 4) {
track2 = 0; // reset writing count
curr = currLine.slice(track - 4, track); // store 4 previous bytes as writing source
if (lineCount === 1 && lineWidth - track < 30) console.log(curr); //debug
} else {
curr = currLine; //set normal scanline
}
Iteration 0: val == true, track2 == 4, set curr to next pixel, write red channel.
Iteration 1: val == true, track2 == 1, (val && track2 === 4) == false, set curr to currLine, write green channel.
You can move track2 === 4 branch to avoid this:
if (val) {
if (track2 === 4) {
track2 = 0; // reset writing count
curr = currLine.slice(track - 4, track); // store 4 previous bytes as writing source
if (lineCount === 1 && lineWidth - track < 30) console.log(curr); //debug
}
} else {
curr = currLine; //set normal scanline
}
Fixed code should look like this:
function flipAlt(input, output) {
const fs = require('fs');
const jpeg = require('jpeg-js');
let a = fs.readFileSync(input);
let b = jpeg.decode(a);
let d = Buffer.allocUnsafe(b.width * b.height * 4);
let val = false; // track whether normal or reversed scanlines
let lineWidth = b.width * 4;
let lineCount = 0;
let track = 0;
let track2 = 0;
let track3 = 0;
let curr, currLine; // storage for writing/reading scnalines, respectively
let limit = {
one: Math.floor(Math.random() * 141),
two: Math.floor(Math.random() * 151),
three: Math.floor(Math.random() * 121)
};
if (limit.one < 30) {
limit.one = 30;
}
if (limit.two < 40) {
limit.two = 40;
}
if (limit.two < 20) {
limit.two = 20;
}
let calc = {};
calc.floor = 0;
calc.ceil = 0 + lineWidth;
d.forEach(function(item, i) {
if (i % lineWidth === 0) {
lineCount++;
if (lineCount > 1) {
val = !val;
}
if (lineCount === 1) {
val = !val; // setting alt scanline check to true initially
} else if (calc.floor + lineWidth < b.data.length - 1) {
calc.floor += lineWidth;
calc.ceil += lineWidth;
}
currLine = b.data.slice(calc.floor, calc.ceil); // current line
track = val ? lineWidth : 0; // tracking variable for reading from scanline
track2 = val ? 4 : 0; // tracking variable for writing from scanline
}
//check if reversed and writing variable has written 4 bytes for RGBA
//if so, set writing source to 4 bytes at end of line and read from there incrementally
if (val) {
if (track2 === 4) {
track2 = 0; // reset writing count
curr = currLine.slice(track - 4, track); // store 4 previous bytes as writing source
if (lineCount === 1 && lineWidth - track < 30) console.log(curr); //debug
}
} else {
curr = currLine; //set normal scanline
}
d[i] = curr[track2];
// check if there is no match between data source and decoded image
if (d[i] !== curr[track2]) {
if (track3 < 50) {
console.log(i);
}
track3++;
}
track2++; //update tracking variable
track = val ? track - 1 : track + 1; //update tracking variable
});
var rawImageData = {
data: d,
width: b.width,
height: b.height
};
console.log(b.data.length);
console.log('errors\t', track3);
var jpegImageData = jpeg.encode(rawImageData, 100);
fs.writeFile(output, jpegImageData.data);
}
flipAlt('input.jpg', 'output.jpg');
Instead of tracking array indices, you can use utility library like lodash, it should make things easier:
function flipAlt(input, output) {
const fs = require('fs');
const jpeg = require('jpeg-js');
const _ = require('lodash');
const image = jpeg.decode(fs.readFileSync(input));
const lines = _.chunk(image.data, image.width*4);
const flipped = _.flatten(lines.map((line, index) => {
if (index % 2 != 0) {
return line;
}
const pixels = _.chunk(line, 4);
return _.flatten(pixels.reverse());
}));
const imageData = jpeg.encode({
width: image.width,
height: image.height,
data: new Buffer(flipped)
}, 100).data;
fs.writeFile(output, imageData);
}
flipAlt('input.jpg', 'output.jpg');

Calculate the bounding box of STL file with JavaScript

So I am using this npm package: node-stl
And its working great. However the regexp syntax, mathematics and geometrical calculations are somewhat confusing to me. Especially all at the same time.
Basically what I want to achieve is to extend the script to calculate the bounding box of the STL.
Here is the main file that calculates the volume and weight of the STL being parsed/read.
var fs = require('fs');
// Vertex
function Vertex (v1,v2,v3) {
this.v1 = Number(v1);
this.v2 = Number(v2);
this.v3 = Number(v3);
}
// Vertex Holder
function VertexHolder (vertex1,vertex2,vertex3) {
this.vert1 = vertex1;
this.vert2 = vertex2;
this.vert3 = vertex3;
}
// transforming a Node.js Buffer into a V8 array buffer
function _toArrayBuffer (buffer) {
var
ab = new ArrayBuffer(buffer.length),
view = new Uint8Array(ab);
for (var i = 0; i < buffer.length; ++i) {
view[i] = buffer[i];
}
return ab;
}
// calculation of the triangle volume
// source: http://stackoverflow.com/questions/6518404/how-do-i-calculate-the-volume-of-an-object-stored-in-stl-files
function _triangleVolume (vertexHolder) {
var
v321 = Number(vertexHolder.vert3.v1 * vertexHolder.vert2.v2 * vertexHolder.vert1.v3),
v231 = Number(vertexHolder.vert2.v1 * vertexHolder.vert3.v2 * vertexHolder.vert1.v3),
v312 = Number(vertexHolder.vert3.v1 * vertexHolder.vert1.v2 * vertexHolder.vert2.v3),
v132 = Number(vertexHolder.vert1.v1 * vertexHolder.vert3.v2 * vertexHolder.vert2.v3),
v213 = Number(vertexHolder.vert2.v1 * vertexHolder.vert1.v2 * vertexHolder.vert3.v3),
v123 = Number(vertexHolder.vert1.v1 * vertexHolder.vert2.v2 * vertexHolder.vert3.v3);
return Number(1.0/6.0)*(-v321 + v231 + v312 - v132 - v213 + v123);
}
// parsing an STL ASCII string
function _parseSTLString (stl) {
var totalVol = 0;
// yes, this is the regular expression, matching the vertexes
// it was kind of tricky but it is fast and does the job
var vertexes = stl.match(/facet\s+normal\s+([-+]?\b(?:[0-9]*\.)?[0-9]+(?:[eE][-+]?[0-9]+)?\b)\s+([-+]?\b(?:[0-9]*\.)?[0-9]+(?:[eE][-+]?[0-9]+)?\b)\s+([-+]?\b(?:[0-9]*\.)?[0-9]+(?:[eE][-+]?[0-9]+)?\b)\s+outer\s+loop\s+vertex\s+([-+]?\b(?:[0-9]*\.)?[0-9]+(?:[eE][-+]?[0-9]+)?\b)\s+([-+]?\b(?:[0-9]*\.)?[0-9]+(?:[eE][-+]?[0-9]+)?\b)\s+([-+]?\b(?:[0-9]*\.)?[0-9]+(?:[eE][-+]?[0-9]+)?\b)\s+vertex\s+([-+]?\b(?:[0-9]*\.)?[0-9]+(?:[eE][-+]?[0-9]+)?\b)\s+([-+]?\b(?:[0-9]*\.)?[0-9]+(?:[eE][-+]?[0-9]+)?\b)\s+([-+]?\b(?:[0-9]*\.)?[0-9]+(?:[eE][-+]?[0-9]+)?\b)\s+vertex\s+([-+]?\b(?:[0-9]*\.)?[0-9]+(?:[eE][-+]?[0-9]+)?\b)\s+([-+]?\b(?:[0-9]*\.)?[0-9]+(?:[eE][-+]?[0-9]+)?\b)\s+([-+]?\b(?:[0-9]*\.)?[0-9]+(?:[eE][-+]?[0-9]+)?\b)\s+endloop\s+endfacet/g);
vertexes.forEach(function (vert) {
var preVertexHolder = new VertexHolder();
vert.match(/vertex\s+([-+]?\b(?:[0-9]*\.)?[0-9]+(?:[eE][-+]?[0-9]+)?\b)\s+([-+]?\b(?:[0-9]*\.)?[0-9]+(?:[eE][-+]?[0-9]+)?\b)\s+([-+]?\b(?:[0-9]*\.)?[0-9]+(?:[eE][-+]?[0-9]+)?\b)\s/g).forEach(function (vertex, i) {
var tempVertex = vertex.replace('vertex', '').match(/[-+]?[0-9]*\.?[0-9]+/g);
var preVertex = new Vertex(tempVertex[0],tempVertex[1],tempVertex[2]);
preVertexHolder['vert'+(i+1)] = preVertex;
});
var partVolume = _triangleVolume(preVertexHolder);
totalVol += Number(partVolume);
})
var volumeTotal = Math.abs(totalVol)/1000;
return {
volume: volumeTotal, // cubic cm
weight: volumeTotal * 1.04 // gm
}
}
// parsing an STL Binary File
// (borrowed some code from here: https://github.com/mrdoob/three.js/blob/master/examples/js/loaders/STLLoader.js)
function _parseSTLBinary (buf) {
buf = _toArrayBuffer(buf);
var
headerLength = 80,
dataOffset = 84,
faceLength = 12*4 + 2,
le = true; // is little-endian
var
dvTriangleCount = new DataView(buf, headerLength, 4),
numTriangles = dvTriangleCount.getUint32(0, le),
totalVol = 0;
for (var i = 0; i < numTriangles; i++) {
var
dv = new DataView(buf, dataOffset + i*faceLength, faceLength),
normal = new Vertex(dv.getFloat32(0, le), dv.getFloat32(4, le), dv.getFloat32(8, le)),
vertHolder = new VertexHolder();
for(var v = 3; v < 12; v+=3) {
var vert = new Vertex(dv.getFloat32(v*4, le), dv.getFloat32((v+1)*4, le), dv.getFloat32( (v+2)*4, le ) );
vertHolder['vert'+(v/3)] = vert;
}
totalVol += _triangleVolume(vertHolder);
}
var volumeTotal = Math.abs(totalVol)/1000;
return {
volume: volumeTotal, // cubic cm
weight: volumeTotal * 1.04 // gm
}
}
// NodeStl
// =======
// > var stl = NodeStl(__dirname + '/myCool.stl');
// > console.log(stl.volume + 'cm^3');
// > console.log(stl.weight + 'gm');
function NodeStl (stlPath) {
var
buf = fs.readFileSync(stlPath),
isAscii = true;
for (var i=0, len=buf.length; i<len; i++) {
if (buf[i] > 127) { isAscii=false; break; }
}
if (isAscii)
return _parseSTLString(buf.toString());
else
return _parseSTLBinary(buf);
}
module.exports = NodeStl;
If anyone could help me with this it would be great. I know and it feels like it simple. That I just need to know max/min of the different directions(x,y,z) and could then calculate the bounding box.
But I do not understand what the max/min for x,y and z is here. Please answer if you have an idea.
I've made a new branch https://github.com/johannesboyne/node-stl/tree/boundingbox could you please verify whether the applied algorithm works?
Best,
Johannes
Edit: If the branch is stable -> works I'll push it into v.0.1.0 (don't know why it is still 0.0.1)

AS3 (string).split quotation mark only

I want to split up a document by quotation it's marks. I see (here) that they're able to fake this answer by adding a '\' at the beginning of the quotation mark, however in my document there are hundreds of these strings I'm trying to cut string out of, so changing that manually would be a real pain and time taker.
Here's an example of the string I'm trying to cut from:
D
And here's an example of my current code:
private function onShopTextLoaded(e:Event):void
{
shopArrayOfWebsites = e.target.data.split(/\n/);
for (var i:String in shopArrayOfWebsites)
{
trace("shopArrayOriginal: " + shopArrayOfWebsites[i]);
var arrayString:String = shopArrayOfWebsites[i].split('"' /* << that won't work */ );
trace(arrayString[1]);
//shopArrayOfWebsites[i] = arrayString[1];
}
}
private function postInShopView():void
{
var iLevel:Number = 1;
var iSection:Number = 1;
var iShop:Number = 0;
for (var i:String in shopArrayOfWebsites)
{
iShop++;
if(iShop >= 5)
{
iSection++;
iShop = 0;
}
if(iSection >= 5)
{
iLevel++;
iSection = 1;
}
var shopStringEquiv:String = "L" + iLevel.toString() + "S" + iSection.toString() + "Shop" + iShop.toString();
if(global.shopTarget == shopStringEquiv)
{
var result:uint = ExternalInterface.call("showShopFrame", shopArrayOfWebsites[i]);
}
//trace(shopStringEquiv);
//trace(shopArrayOfWebsites[i]);
}
}
I get an error of:
ReferenceError: Error #1069: Property 1 not found on String and there is no default value.
So from here I'm not quite sure how I'm able to split up this document. Any ideas? Thanks!

When adding a single letter at a time to a text field, how do I avoid the word wrap occuring mid-word?

Given the following example SWF:
Sample
Notice how with the words "enthusiast" at the end of the first line and "write" at the end of the second line, that they start to type out on the first line but after a few letters they are bumped.
I understand this is the correct behavior, but is there a way for "enthusiast" to begin being typed on the second line, and "write" on the third line instead of being bumped during the typing?
Currently I am thinking of doing a search ahead mechanism, so it finds the next word in whole, then makes that the active word to print, temporarily print it, see if it increases the numlines, and if it does insert a line break and continue writing. But it seems fiddly.
Code below:
import flash.text.TextField;
import flash.events.Event;
var tt:TextField = new TextField();
tt.wordWrap = true;
tt.width = 200;
tt.height = 50;
tt.border = true;
var s = "Stack Overflow is for professional and enthusiast programmers, people who write code because they love it. We feel the best Stack Overflow questions have a bit of source code in them, but if your question generally covers";
addChild(tt);
var currentLetter:int = 0;
addEventListener(Event.ENTER_FRAME, onEnter, false, 0, true);
function onEnter(e:Event):void
{
if(currentLetter < s.length)
{
tt.appendText(s.charAt(currentLetter));
}
currentLetter++;
}
adjusted your code a bit and posted the result on wonderfl: http://wonderfl.net/c/rZkm
as #mouseas suggested i put the next word into an additional textfield measure the width and compare this to the remaining space in the current line ... if the next word doesn't fit I add a line-break and continue.
here's the code:
package {
import flash.geom.Rectangle;
import flash.text.TextFieldAutoSize;
import flash.display.Sprite;
import flash.text.TextField;
import flash.events.Event;
public class FlashTest extends Sprite {
private var currentLetter:int = 0;
private var tt:TextField;
private var debug:TextField;
private var pre:TextField;
private var s:String;
public function FlashTest()
{
// write as3 code here..
tt = new TextField();
tt.wordWrap = true;
tt.width = 200;
tt.height = 150;
tt.border = true;
s = "Stack Overflow is for professional and enthusiast programmers, people who write code because they love it. We feel the best Stack Overflow questions have a bit of source code in them, but if your question generally covers";
addChild(tt);
// predraw word
pre = new TextField();
pre.y = 150;
pre.width = 200;
pre.height = 50;
pre.autoSize = TextFieldAutoSize.LEFT;
pre.border = true;
addChild(pre);
// debug txt
debug = new TextField();
debug.x = 250;
debug.wordWrap = true;
debug.width = 200;
debug.height = 500;
debug.border = true;
addChild(debug);
addEventListener(Event.ENTER_FRAME, onEnter, false, 0, true);
}
private function onEnter(e:Event):void
{
//debug.appendText("char: " + rect.x + " " + rect.width + "\n");
var c:String = "";
if (currentLetter < s.length)
{
c = s.charAt(currentLetter);
tt.appendText(c);
}
else
{
debug.appendText("DONE! \n");
removeEventListener(Event.ENTER_FRAME, onEnter);
}
if (c == " ")
{
var rect:Rectangle = tt.getCharBoundaries(currentLetter-1);
if (rect != null)
{
//debug.appendText("char: " + rect + "\n");
var cPos:int = rect.x + rect.width;
var r:int = tt.width - 4 - cPos; // 4px for gutter on left+right side of textfield
var start:int = s.lastIndexOf(" ", currentLetter);
var end:int = s.indexOf(" ", currentLetter+1);
if (start < 0) start = 0;
pre.text = s.substr(start, end-start);
debug.appendText("rest: " + r + " " + pre.textWidth + " > " + pre.text + "\n");
if (r - pre.textWidth <= 0)
{
tt.appendText("\n");
debug.appendText("\n");
}
//debug.appendText("w:" + tt.textWidth + " " + start + "->"+ end + " /" + pre.text + "/ " + pre.textWidth + "\n");
}
}
++currentLetter;
}
}
}
works great - only the "a" in the 4th line makes trouble - maybe you need to finetune the calculations a bit...

YUI - Get True element width?

I am using YUI and need to get the true width of the element. The width of an element can be determined as follows.
width + border-left + border-right + padding-left + padding-right + margin-left + margin-right.
Below is what I have come up with. It appears to be working. I was just wondering if this is the best way to go about determining this or is there there a more efficient way?
YUI().use('node', function(Y) {
var node = Y.one('#nav');
var nodeWidth = trueElementWidth(node);
alert(nodeWidth);
});
function trueElementWidth(el) {
var width = 0;
var attributes = ['border-left', 'border-right', 'padding-left', 'padding-right', 'width', 'margin-right', 'margin-left'];
for(var i=0; i < attributes.length; i++) {
width = width + removePx(el.getComputedStyle(attributes[i]));
}
return width;
}
function removePx(el) {
el = el.toString();
length = el.length - 2;
elDimension = parseInt(el.substring(0, length));
return isNaN(elDimension) ? 0 : elDimension;
}
There is an offsetWidth property that returns exactly what you want.

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