Paper.js animate path move on click - javascript

What iam trying to do, is this:
click somewhere (get position of click)
tell to path "go to the clicked spot"
path is moving smoothly via animate to clicked location
so far i have this code:
paper.tool.onMouseDown = function(event) {
x = event.event.offsetX;
y = event.event.offsetY;
paper.view.attach('frame', moveSeg);
}
var x;
var y;
function moveSeg(event) {
event.count = 1;
if(event.count <= 100) {
myPath.firstSegment.point._x += (x / 100);
myPath.firstSegment.point._y += (y / 100);
for (var i = 0; i < points - 1; i++) {
var segment = myPath.segments[i];
var nextSegment = segment.next;
var vector = new paper.Point(segment.point.x - nextSegment.point.x,segment.point.y - nextSegment.point.y);
vector.length = length;
nextSegment.point = new paper.Point(segment.point.x - vector.x,segment.point.y - vector.y);
}
myPath.smooth();
}
}
working jsfiddle
current code is obviously wrong. The path is always going bottom right and there are other problems. I guess that what i could use is something like this:
jsfiddle
But iam having problems to understand how it works.

You have to edit the following lines to this:
myPath.firstSegment.point._x += (x - myPath.firstSegment.point._x)/10;
myPath.firstSegment.point._y += (y - myPath.firstSegment.point._y)/10;
Here is your changed jsfiddle. If you want to understand what I did and how to improve your code maybe try to read a bit about vector geometry on the paperjs website.

Related

JS Canvas - Filling a bean-shaped polygon

I have a problem with JS canvas ctx.fill() filling outside of my polygonal shape.
Here's how my code works :
ctx.beginPath()
// Here are for loops that draws a the closed shape using
ctx.stroke();
ctx.fill();
Here are the for loops:
var sx1, sy1, ex1, ey1, sx2, sy2, ex2, ey2;
for(var i = 0; i < n; i += Math.floor(n/steps)){
var radius = Math.exp(-2*i/n)*rmax+rmin;
radius += frequencyData[i]/255*(n-i + 200)/n*50;
var angle = -Math.PI/2 - i/n*2*Math.PI;
var x = radius*Math.cos(angle) + w/2+rmin/2;
var y = radius*Math.sin(angle) + (h-110)/2+rmin/2 + analyser_offset;
if (i == 0) {
gctx.moveTo(x,y);
sx1 = x;
sy1 = y;
}else if (i == n-1){
ex1 = x;
ey1 = y;
}else{
gctx.lineTo(x,y);
}
spd += frequencyData[i];
}
for(var i = 0; i < n; i += Math.floor(n/steps)){
var radius = Math.exp(-2*i/n)*rmax+rmin;
radius -= frequencyData[i]/255*(n-i + 200)/n*50;
var angle = -Math.PI/2 - i/n*2*Math.PI;
var x = radius*Math.cos(angle) + w/2+rmin/2;
var y = radius*Math.sin(angle) + (h-110)/2+rmin/2 + analyser_offset;
if (i == 0) {
gctx.moveTo(x,y);
}else if (i == 20){
sx2 = x;
sy2 = y;
}else if (i == n-1){
ex2 = x;
ey2 = y;
} else {
gctx.lineTo(x,y);
}
}
gctx.moveTo(sx1, sy1);
gctx.lineTo(sx2, sy2);
gctx.moveTo(ex1, ey1);
gctx.lineTo(ex2, ey2);
So the first for loop draws the outter side of the shape, the second for loop draws the inner side. And then the sx1, sy1, ex1, ey1, sx2, sy2, ex2, ey2 variables are here to ensure that in the last 4 lines, it closes the shape (by adding vertical line between the outter and inner lines). Maybe this problem happens because I draw the lines in an unusual order? (like drawing a rectangle by starting with 2 horizontal lines and then adding 2 vertical ones)
Here's what I get after the fill() :
And this is what I would like to have:
So could you guide me on how I'm supposed to achieve this?
Ok I fixed it by making the second loop go in the reverse order like this: for (var i = n-1; i >= 0; i -= Math.floor(n/steps)) so it draws the polygon in a more usual order and that works! I don't even need to close it using the last 4 lines which was what I wanted so that's great!

Javascript onclick event on newly created elements

I've got several functions all linked so it will ...
create new elements and set their properties and stuff
once elements are in place they should trigger function.
And they do! Kind of...
More like they trigger half of a function that's attached to them upon creation. The part where they onclick trigger a function that starts a loading on my progress bar (which is their purpose) is alright. But the much simpler part, where they hide after click, doesn't.
As the code is quite complex I'll place here larger part of it, so don't panic. Problem might be somewhere else then I expect. Here it is...
// defines function for checkpoint
function checkpointed() {
this.style.display = 'none'; // !here dwells the douch part!
if (toLoad < 100) {
toLoad += 100/$(this).attr('numButs');
var sim = setInterval(progressSim, 50);
}
// defining creation of checkpoints
function checkpoints(num) {
var angle = 4.72,
step = (2 * Math.PI) / num;
for (i = 1; i < num + 1; i++) {
var x = $('#progressBar').width()/2 + radius * Math.cos(angle) ;
var y = $('#progressBar').height()/2 + radius * Math.sin(angle);
angle += step;
var newContent = document.createElement('IMG');
var newCheckpoint = document.createElement('SPAN');
var numButs = document.createAttribute('numButs');
numButs.value = num;
var Class = document.createAttribute('class');
Class.value = 'checkpoint';
var img = document.createAttribute('src');
img.value = 'img/lock.png';
newContent.setAttributeNode(img);
newCheckpoint.setAttributeNode(numButs);
newCheckpoint.setAttributeNode(Class);
$(newCheckpoint).append(newContent);
$('.projectBar').append(newCheckpoint);
x -= 24;
y -= 24;
$(newCheckpoint).offset({top:y, left: x});
newCheckpoint.onclick = checkpointed;
};
};
// creates checkpoints upon clicking on create button
document.getElementById('create').onclick = function(){
checkpoints(document.getElementById('numCheckpoint').value);
$(this).hide();
$('#numCheckpoint').hide();
};
I should probably sum up what is this all about.
I have circular progressBar that measures progression of users project. User says "Hey, my project has like 5 steps (or 20 idc)" and "create" button will make 5 checkpoints placed on the progressBar evenly. By clicking on checkpoints you load the progress bar by 20% per clicked checkpoint.
Don't worry though, I've already figured out the code for loading and the geometrics.
However I'm bit stuck here... on simple onclick functions. Please if you have an idea try achieve it with plain JavaScript or jQuery (trying to do this without other frameworks, libraries or plugins).
EDIT: Just found out that checkpoint are set alright, as they really hide after clicking. Problem is in creation of checkpoints as the loop creates about 15 more checkpoints stacked one on another. So you have to click each of them to hide them all... So problem is in the loop.
EDIT2: Figured it out. The loop for (i = 1; i < num + 1; i++) had the numparameter as a String coming from input field. So simple parseInt() did the trick.
The mixed Jquery and plain Javascript is messing with my head... Any way how about when you create a new element, give it some sort of class. Instead of giving setting onclick, use jQuery's on selector to bind click events to those dynamic elements. Try The Following:
$(document).on("click", ".Checkpoint", function(event) {
$(event.target).hide();
if (toLoad < 100) {
toLoad += 100 / $(this).attr('numButs');
var sim = setInterval(progressSim, 50);
}
});
// defining creation of checkpoints
function checkpoints(num) {
var angle = 4.72,
step = (2 * Math.PI) / num;
for (i = 1; i < num + 1; i++) {
var x = $('#progressBar').width() / 2 + radius * Math.cos(angle);
var y = $('#progressBar').height() / 2 + radius * Math.sin(angle);
angle += step;
var newContent = $('<img></img>');
var newCheckpoint = $('<span></span>');
$("body").append(newCheckpoint);
newContent.attr("numButs", num);
newContent.attr("src", 'img/lock.png');
newContent.addClass("Checkpoint");
$(newCheckpoint).append(newContent);
$('.projectBar').append(newCheckpoint);
x -= 24;
y -= 24;
$(newCheckpoint).offset({
top: y,
left: x
});
}
}
// creates checkpoints upon clicking on create button
$(document).on("click","#create",function(e) {
checkpoints($('#numCheckpoint').val());
$(e.target).hide();
$('#numCheckpoint').hide();
});
Changed stuff to work more in jQuery, hope you don't mind...

Algorithm to find space for an object within a 2d area

I'm building a website which uses jQuery to allow users to add widgets to a page, drag them around and resize them (the page is fixed width and infinite height.) The issue that I'm having is that when adding a new widget to the page I have to find a free space for it (the widgets cannot overlap and I'd like to favour spaces at the top of the page.)
I've been looking at various packing algorithms and none of them seem to be suitable. The reason why is that they are designed for packing all of the objects in to the container, this means that all of the previous rectangles are laid out in a uniform way. They often line up an edge of the rectangle so that they form rows/columns, this simplifies working out what will fit where in the next row/column. When the user can move/resize widgets at will these algorithms don't work well.
I thought that I had a partial solution but after writing some pseudo code in here I’ve realized that it won’t work. A brute force based approach would work, but I'd prefer something more efficient if possible. Can anyone suggest a suitable algorithm? Is it a packing algorithm that I'm looking for or would something else work better?
Thanks
Ok, I've worked out a solution. I didn't like the idea of a brute force based approach because I thought it would be inefficient, what I realized though is if you can look at which existing widgets are in the way of placing the widget then you can skip large portions of the grid.
Here is an example: (the widget being placed is 20x20 and page width is 100px in this example.)
This diagram is 0.1 scale and got messed up so I've had to add an extra column
*123456789A*
1+---+ +--+1
2| | | |2
3| | +--+3
4| | 4
5+---+ 5
*123456789A*
We attempt to place a widget at 0x0 but it doesn't fit because there is a 50x50 widget at that coordinate.
So we then advance the current x coordinate being scanned to 51 and check again.
We then find a 40x30 widget at 0x61.
So we then advance the x coordinate to 90 but this doesn't leave enough room for the widget being placed so we increment the y coordinate and reset x back to 0.
We know from the previous attempts that the widgets on the previous line are at least 30px high so we increase the y coordinate to 31.
We encounter the same 50x50 widget at 0x31.
So we increase x to 51 and find that we can place a widget at 51x31
Here is the javascript:
function findSpace(width, height) {
var $ul = $('.snap-layout>ul');
var widthOfContainer = $ul.width();
var heightOfContainer = $ul.height();
var $lis = $ul.children('.setup-widget'); // The li is on the page and we dont want it to collide with itself
for (var y = 0; y < heightOfContainer - height + 1; y++) {
var heightOfShortestInRow = 1;
for (var x = 0; x < widthOfContainer - width + 1; x++) {
console.log(x + '/' + y);
var pos = { 'left': x, 'top': y };
var $collider = $(isOverlapping($lis, pos, width, height));
if ($collider.length == 0) {
// Found a space
return pos;
}
var colliderPos = $collider.position();
// We have collided with something, there is no point testing the points within this widget so lets skip them
var newX = colliderPos.left + $collider.width() - 1; // -1 to account for the ++ in the for loop
x = newX > x ? newX : x; // Make sure that we are not some how going backwards and looping forever
var colliderBottom = colliderPos.top + $collider.height();
if (heightOfShortestInRow == 1 || colliderBottom - y < heightOfShortestInRow) {
heightOfShortestInRow = colliderBottom - y; // This isn't actually the height its just the distance from y to the bottom of the widget, y is normally at the top of the widget tho
}
}
y += heightOfShortestInRow - 1;
}
//TODO: Add the widget to the bottom
}
Here is the longer and more less elegant version that also adjusts the height of the container (I've just hacked it together for now but will clean it up later and edit)
function findSpace(width, height,
yStart, avoidIds // These are used if the function calls itself - see bellow
) {
var $ul = $('.snap-layout>ul');
var widthOfContainer = $ul.width();
var heightOfContainer = $ul.height();
var $lis = $ul.children('.setup-widget'); // The li is on the page and we dont want it to collide with itself
var bottomOfShortestInRow;
var idOfShortestInRow;
for (var y = yStart ? yStart : 0; y <= heightOfContainer - height + 1; y++) {
var heightOfShortestInRow = 1;
for (var x = 0; x <= widthOfContainer - width + 1; x++) {
console.log(x + '/' + y);
var pos = { 'left': x, 'top': y };
var $collider = $(isOverlapping($lis, pos, width, height));
if ($collider.length == 0) {
// Found a space
return pos;
}
var colliderPos = $collider.position();
// We have collided with something, there is no point testing the points within this widget so lets skip them
var newX = colliderPos.left + $collider.width() - 1; // -1 to account for the ++ in the for loop
x = newX > x ? newX : x; // Make sure that we are not some how going backwards and looping forever
colliderBottom = colliderPos.top + $collider.height();
if (heightOfShortestInRow == 1 || colliderBottom - y < heightOfShortestInRow) {
heightOfShortestInRow = colliderBottom - y; // This isn't actually the height its just the distance from y to the bottom of the widget, y is normally at the top of the widget tho
var widgetId = $collider.attr('data-widget-id');
if (!avoidIds || !$.inArray(widgetId, avoidIds)) { // If this is true then we are calling ourselves and we used this as the shortest widget before and it didnt work
bottomOfShortestInRow = colliderBottom;
idOfShortestInRow = widgetId;
}
}
}
y += heightOfShortestInRow - 1;
}
if (!yStart) {
// No space was found so create some
var idsToAvoid = [];
for (var attempts = 0; attempts < widthOfContainer; attempts++) { // As a worse case scenario we have lots of 1px wide colliders
idsToAvoid.push(idOfShortestInRow);
heightOfContainer = $ul.height();
var maxAvailableRoom = heightOfContainer - bottomOfShortestInRow;
var extraHeightRequired = height - maxAvailableRoom;
if (extraHeightRequired < 0) { extraHeightRequired = 0;}
$ul.height(heightOfContainer + extraHeightRequired);
var result = findSpace(width, height, bottomOfShortestInRow, idsToAvoid);
if (result.top) {
// Found a space
return result;
}
// Got a different collider so lets try that next time
bottomOfShortestInRow = result.bottom;
idOfShortestInRow = result.id;
if (!bottomOfShortestInRow) {
// If this is undefined then its broken (because the widgets are bigger then their contianer which is hardcoded atm and resets on f5)
break;
}
}
debugger;
// Something has gone wrong so we just stick it on the bottom left
$ul.height($ul.height() + height);
return { 'left': 0, 'top': $ul.height() - height };
} else {
// The function is calling itself and we shouldnt recurse any further, just return the data required to continue searching
return { 'bottom': bottomOfShortestInRow, 'id': idOfShortestInRow };
}
}
function isOverlapping($obsticles, tAxis, width, height) {
var t_x, t_y;
if (typeof (width) == 'undefined') {
// Existing element passed in
var $target = $(tAxis);
tAxis = $target.position();
t_x = [tAxis.left, tAxis.left + $target.outerWidth()];
t_y = [tAxis.top, tAxis.top + $target.outerHeight()];
} else {
// Coordinates and dimensions passed in
t_x = [tAxis.left, tAxis.left + width];
t_y = [tAxis.top, tAxis.top + height];
}
var overlap = false;
$obsticles.each(function () {
var $this = $(this);
var thisPos = $this.position();
var i_x = [thisPos.left, thisPos.left + $this.outerWidth()]
var i_y = [thisPos.top, thisPos.top + $this.outerHeight()];
if (t_x[0] < i_x[1] && t_x[1] > i_x[0] &&
t_y[0] < i_y[1] && t_y[1] > i_y[0]) {
overlap = this;
return false;
}
});
return overlap;
}

How to add the vertical parallel lines in the rectangle?

I want to add the vertical lines when I draw rectangle. The no of lines is dependent on the user and can be read from the text box.
I know the logic but somehow I am not able to get the answer.
I am calculating the width of the rectangle and then diving the width on the basis of no of vertical lines.
Click the checkbox near rectangle and draw using mouse down events
Please let me know where I am going wrong.
function PlotPitch()
{
var iPatches = document.getElementById('txtPatchCount').value;
var iTop = mySel.y;
var iBottom = mySel.y + mySel.h;
var iLeft = mySel.x;
var iX = iLeft;
canvas = document.getElementById('canvas2');
context = canvas.getContext('2d');
for (var iPatch=1; iPatch<iPatches; ++iPatch) {
iX = iLeft + iPatch*mySel.w/iPatches;
context.moveTo(iX, iTop);
context.lineTo(iX, iBottom);
}
context.lineWidth=0.25;
context.stroke();
}
http://jsfiddle.net/K5wcs/4/
If I am adding this the code is breaking and I am not able to draw anything.
What you should do if you have 'strange' behaviour is to separate concerns, so in this case that could be by creating a function that you test separately, which draws the lines, then once it's tested ok, plug it in code by just calling the function. You should find quickly.
So begin by testing this :
function drawLines(Context, mySel, iPatches) {
var iTop = mySel.y;
var iBottom = mySel.y + mySel.h;
var iLeft = mySel.x;
var iX = iLeft;
var colWidth = mySel.w/iPatches ;
for (var iPatch=1; iPatch<iPatches; ++iPatch) {
iX += colWidth;
Context.moveTo(iX, iTop);
Context.lineTo(iX, iBottom);
}
Context.lineWidth=0.25;
Context.stroke();
}
Good luck.

Point in Polygon falsely detected

Derived from this: How to tackle diagonally stacked, rounded image background element hovers?
I made imagemap areas and transformed them for my case, but, now there is a problem with point in polygon hit detection.
It appears that only the bottom right quadrant is always correct, but, only if looking outside the ring - inside the detection might be still be incorrect. Other quadrants, outside the ring, occasionally report a positive hit where it should be false.
Fiddle: http://jsfiddle.net/psycketom/9J4dx/1/
The red lines are drawn from the polygon that's generated from data-map.
The blue line represents the polygon we're currently checking.
The point in polygon function comes from: https://github.com/substack/point-in-polygon
var pointInPolygon = function(point, vs)
{
// ray-casting algorithm based on
// http://www.ecse.rpi.edu/Homepages/wrf/Research/Short_Notes/pnpoly.html
var x = point[0], y = point[1];
var inside = false;
for (var i = 0, j = vs.length - 1; i < vs.length; j = i++) {
var xi = vs[i][0], yi = vs[i][1];
var xj = vs[j][0], yj = vs[j][1];
var intersect = ((yi > y) != (yj > y))
&& (x < (xj - xi) * (y - yi) / (yj - yi) + xi);
if (intersect) inside = !inside;
}
return inside;
};
I cannot seem to understand what's the problem here.
Your mapToPolygon function doesn't convert the parsed points from string to number. Because of this, the pointInPolygon function ends up comparing the strings of the coordinates, not the actual coordinates. Using a parseInt on line 31 of the fiddle fixes the problem.
Create an off-screen canvas and use the context's .isPointInPath(x, y) function.
Loop through all of your polygons (in your example you would loop through them in reverse because you have smallest last. The smallest would be the highest level / greatest z-index).
On you get a hit (isPointInPath returns true) stop.
Something like...
var offcanvas = document.createElement("canvas");
...
var x = e.pageX - $ages.offset().left;
var y = e.pageY - $ages.offset().top;
revlayers.each(function() {
var $elm = $(this);
var poly = $elm.data("polygon");
var ctx = offcanvas.getContext("2d");
if(poly.length > 0) {
ctx.beginPath();
ctx.moveTo(poly[0][0], poly[0][1]);
for(var i=1; i<poly.length; i++) {
ctx.lineTo(poly[i][0], poly[i][1]);
}
if(ctx.isPointInPath(x, y)) {
hit.text($elm.attr("href"));
return false; // end the .each() loop
}
}
})

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