Develop Reference

How to get drawline to work in Internet Explorer?

I have a function that draws a line inside a div (adapted from this solution), used in an e-learning module (explains the weird parts of the code).
My problem is that it doesn't seem to work in IE11.
Here is the code:
var player = GetPlayer();
var progress = player.GetVar("score");
var h = 600; //the height of your slide, as set in Story Size
var w = 1000; //the width of your slide, as set in Story Size
var t = 4; //the desired thickness of the progress bar in px, as based on the size of the styry slide
var c = "#00cc3399"; //the desired color of the progress bar, in hex. The last 2 digits are opacity. See codes below:
var startY = 40; //the desired start coordinate, from the top of the page
var startX = 0; //the desired start coordinate, from the left side of the page. Set to "0" as standard
var aspectRatio = h/w;
var totalW = $('.slide-container').width(); //get the actual width of the slide. only relevant if storyline is set to "Scale to fill browser window"
var totalH = totalW*aspectRatio; //calculate the actual height of the slide. only relevant if storyline is set to "Scale to fill browser window"
console.log("totalW: " + totalW);
var wFactor = totalW/w; //used to calculate the x-position on the slide. only relevant if storyline is set to "Scale to fill browser window"
var hFactor = totalH/h //used to calculate the y-position on the slide. only relevant if storyline is set to "Scale to fill browser window"
var endPointX = totalW*progress/100; //calculate the length of the progress bar
var endPointY = startY*hFactor; //calculate y-position, based on where you want it to be on the slide. The number is the position on the slide, as seen from the top. This is based on a horizontal progress bar
console.log("endPointX: " + endPointX + ", endPointY: " + endPointY)
x1 = startX, y1 = startY, //Start of the bar
x2 = endPointX, y2 = endPointY; //end of the bar
drawline(x1, y1, x2, y2);
//all the technical stuff:
function drawline(ax, ay, bx, by) {
console.log('ax: ' + ax);
console.log('ay: ' + ay);
console.log('bx: ' + bx);
console.log('by: ' + by);
if (ax > bx) {
bx = ax + bx;
ax = bx - ax;
bx = bx - ax;
by = ay + by;
ay = by - ay;
by = by - ay;
}
console.log('by: ' + by);
var angle = Math.atan((ay - by) / (bx - ax));
angle = (angle * 180 / Math.PI);
angle = -angle;
var length = Math.sqrt((ax - bx) * (ax - bx) + (ay - by) * (ay - by));
console.log('length: ' + length);
var style = ""
style += "left:" + (ax) + "px;"
style += "top:" + (ay) + "px;"
style += "width:" + length + "px;"
style += "height:"+t*hFactor+"px;" //set the thickness of the progress bar
style += "background-color:"+c+";"
style += "position:absolute;"
style += "transform:rotate(" + angle + "deg);"
style += "-ms-transform:rotate(" + angle + "deg);"
style += "transform-origin:0% 0%;"
style += "-moz-transform:rotate(" + angle + "deg);"
style += "-moz-transform-origin:0% 0%;"
style += "-webkit-transform:rotate(" + angle + "deg);"
style += "-webkit-transform-origin:0% 0%;"
style += "-o-transform:rotate(" + angle + "deg);"
style += "-o-transform-origin:0% 0%;"
style += "z-index:99;"
$("<div id='progressBar' style='" + style + "'></div>").appendTo('.slide-container');
};
In chrome this function draws a line based on the user's score. In IE nothing happens.

I found the solution myself. It turns out that IE redefined the 8-digit HEX value to RGBa, and turned it white. Replacing the 8-digit HEX value with it's corresponding RGBa value made it work.

Positioning transformed divs (Trigonometric solution)

I am trying to position some diamond divs using some trigonometry in javascript but it seems my logic fails somewhere.
You can see that I tried this formula: pos + trig * dimension. I hoped it would give me the right coordinates so that I can construct my diamond grid. So my question is, how can I align the diamond borders with trigonometry?
var div = document.getElementsByTagName('div');
var x1 = div[0].offsetTop + Math.cos(45) * div[0].offsetHeight;
var y1 = div[0].offsetLeft + Math.sin(45) * div[0].offsetWidth;
div[1].style.top = y1 + 'px';
div[1].style.left = x1 + 'px';
The entire jsfiddle can be found here: https://jsfiddle.net/hmfxmvvs/
Edit: My intended result is this: https://jsfiddle.net/hmfxmvvs/5/

Try removing .offsetHeight , .offsetWidth from calculations
var x1 = div[0].offsetTop + (Math.cos(45));
var y1 = div[0].offsetLeft + (Math.sin(45));
div[1].style.top = Math.round(y1) + 'px';
div[1].style.left = Math.round(x1) - 9 + 'px';
jsfiddle https://jsfiddle.net/hmfxmvvs/2/

Add non-click function inside of a click function

I have the following problem. I have a .one("click") function with a variable that raises itself, and I need to add a function, that triggers, when the variable hits the wanted point. I mean, in the following code I need to use the connect function for the last 'last' img with the 'home' img, after the Result variable turns 9, which will produce a line between them, and I'll have a complete circle. Please read the code and try clicking on all img-es so that you can understand, what i need to achieve. Thanks in advance.
Here's the code:
$(document).ready(function() {
var Result = 0;
$('img').one("click", function(){
if( $('img.home').length == 0 ){
$(this).addClass('home');
}
if(Result <= 9){
var $elem2 = $('span.last');
var $elem1 = $(this).parent();
$(this).toggleClass('selected');
if ($elem2.length > 0) {
connect($elem1[0], $elem2[0], "#0F0", 5);
}
else {
$elem1.addClass('last');
}
$('span').removeClass('last');
$elem1.addClass('last');
Result++;
}
});
});
function connect(div1, div2, color, thickness) {
var off1 = getOffset(div1);
var off2 = getOffset(div2);
// bottom right
var x1 = off1.left + off1.width;
var y1 = off1.top + off1.height;
// top right
var x2 = off2.left + off2.width;
var y2 = off2.top;
// distance
var length = Math.sqrt(((x2-x1) * (x2-x1)) + ((y2-y1) * (y2-y1)));
distanz += parseInt(length);
// center
var cx = ((x1 + x2) / 2) - (length / 2);
var cy = ((y1 + y2) / 2) - (thickness / 2);
// angle
var angle = Math.atan2((y1-y2),(x1-x2))*(180/Math.PI);
// make hr
var htmlLine = "<div style='padding:0px; margin:0px; height:" + thickness + "px; background-color:" + color + "; line-height:1px; position:absolute; left:" + cx + "px; top:" + cy + "px; width:" + length + "px; -moz-transform:rotate(" + angle + "deg); -webkit-transform:rotate(" + angle + "deg); -o-transform:rotate(" + angle + "deg); -ms-transform:rotate(" + angle + "deg); transform:rotate(" + angle + "deg);' />";
htmlLine = $(htmlLine);
$('body').append(htmlLine);
return htmlLine;
}
function getOffset( el ) {
var x = 0;
var y = 0;
var w = el.offsetWidth|0;
var h = el.offsetHeight|0;
while( el && !isNaN( el.offsetLeft ) && !isNaN( el.offsetTop ) ) {
x += el.offsetLeft - el.scrollLeft;
y += el.offsetTop - el.scrollTop;
el = el.offsetParent;
}
return { top: y, left: x, width: w, height: h };
}
jsfiddle: http://jsfiddle.net/CDQhX/4/
I want to execute the connect(home and span images) after the last line is done and the Result is 9. This can't be done inside the click function, since I'm not clicking anywhere to trigger it. My knowledge don't let me work the problem around. So I appreciate any help. I'll be really glad to receive answers.

First of all, what do you mean you are not clicking anywhere and you want it executed when the last img is clicked. Can't you just check if the img is last when it is clicked, and execute what you need?
Also, on the other hand, you can try setTimeout and setInterval as described here: http://www.w3.org/TR/2011/WD-html5-20110525/timers.html
So, for example, you could do something like this:
setInterval( function() {
//do your thing
}, 500);
Which will execute the function every 500 milliseconds, so you could use that for periodic checking of your variables.

Cropping an image with a preview using jcrop

I'm using jcrop and trying to make a "live" preview of the cropped area on an image.
The movement of the selected area works perfectly if the "Crop Selection" area is the same height and width as the destination preview div.
Check out the issue here: http://jsfiddle.net/fbaAW/
function showCoords(c)
{
var $this = this.ui.holder;
var original = $this.prev();
var preview = original.parent().find(".image");
var oH = original.height();
var oW = original.width();
var pH = preview.height();
var pW = preview.width();
var sH = c.h;
var sW = c.w;
var differenceH = pH - sH;
var differenceW = pW - sW;
//preview.css('width', c.w);
//preview.css('height', c.h);
//preview.css("background-size", Math.round(oW + differenceW) + "px" + " " + Math.round(oH + differenceH) + "px");
preview.css("background-position", Math.round(c.x) * -1 + "px" + " " + Math.round(c.y) * -1 + "px");
}
As you can see, I've commented out a few of my tests and attempts at getting this code to work properly but I just can't wrap my head around the relationship between the position and the size background properties in order to get this effect to work correctly.

Calculate the horizontal and vertical ratios between the selection size and the preview area size:
var rW = pW / c.w;
var rH = pH / c.h;
Then apply them to the background-size and background-position:
preview.css("background-size", (oW*rW) + "px" + " " + (oH*rH) + "px");
preview.css("background-position", rW * Math.round(c.x) * -1 + "px" + " " + rH * Math.round(c.y) * -1 + "px");
http://jsfiddle.net/fbaAW/1/
So, if the preview size is, say, 3 times the size of your jCrop selection area, it means you have scale the original image by 3, and compensate for the scaling when defining the background position.

Can I draw a line using jQuery?

I have a web app where I would like the user to draw a line in the following way: When he clicks on Point1 and he moves the mouse, draw the line from Point1 to the current mouse position and, when clicks to Point2 draw the final line from Point1 to Point2.
How can I do it using jQuery and/or one of its plugins?

Challenge accepted.
I tried to do it with CSS transforms and a bunch of Math in Javascript - after half an hour I have this:
http://jsfiddle.net/VnDrb/2/
Make 2 clicks into the gray square and a line should be drawn.
There is still a small bug that draws the line wrong when the angle is > 45 degree. Maybe someone else knows how to fix that. Maybe instead of using Math.asin (arcsinus), use a other trigonometrical function, but I'm really not good at it.
I thought I'd post it even there is a small bug, I think it's a good start for you.

I've tried a number of different approaches this weekend and the solution that worked best for me is from Adam Sanderson: http://monkeyandcrow.com/blog/drawing_lines_with_css3/
His demo is here: http://monkeyandcrow.com/samples/css_lines/
The core of it is very simple, which is always good.
div.line{
transform-origin: 0 100%;
height: 3px; /* Line width of 3 */
background: #000; /* Black fill */
}
function createLine(x1,y1, x2,y2){
var length = Math.sqrt((x1-x2)*(x1-x2) + (y1-y2)*(y1-y2));
var angle = Math.atan2(y2 - y1, x2 - x1) * 180 / Math.PI;
var transform = 'rotate('+angle+'deg)';
var line = $('<div>')
.appendTo('#page')
.addClass('line')
.css({
'position': 'absolute',
'transform': transform
})
.width(length)
.offset({left: x1, top: y1});
return line;
}

You can not do it with jQuery and classic HTML.
You can do it using SVG (+svgweb for IE8- http://code.google.com/p/svgweb/ )
SVG can be dynamically created. jQuery + svgweb are working perfectly, you just need to know how to create SVG nodes and you need only jquerify this nodes. After jquerifiing in most cases used only one method attr()
You can do it using Raphael http://raphaeljs.com/ (based on SVG and VML)
You can do it using Canvas ( http://flashcanvas.net/ for IE8- )
For SVG programming will be this way:
Moment of creating first point: you create empty line var Line (also this points coordinates will be x1 and y1)
Then you bind on mousemove repaint of x2, y2 properties of Line
On mousedown after mousemove you freeze last line position.
UPDATE
You can do it with CSS/JS, but main problem is in calculations for IE8-, that has only Matrix filter for transformations.

Been using a modified version of this for a while now. Works well.
http://www.ofdream.com/code/css/xline2.php
So on first click, drop and object there as a placeholder div, maybe a little circle, then either keep redrawing a line as they move their mouse, or draw it when they click the second time, using the original placeholder as a guide.
I recently made another helper function for this, because my tool involves moving lines around:
function setLinePos(x1, y1, x2, y2, id) {
if (x2 < x1) {
var temp = x1;
x1 = x2;
x2 = temp;
temp = y1;
y1 = y2;
y2 = temp;
}
var line = $('#line' + id);
var length = Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
line.css('width', length + "px");
var angle = Math.atan((y2 - y1) / (x2 - x1));
line.css('top', y1 + 0.5 * length * Math.sin(angle) + "px");
line.css('left', x1 - 0.5 * length * (1 - Math.cos(angle)) + "px");
line.css('-moz-transform', "rotate(" + angle + "rad)");
line.css('-webkit-transform', "rotate(" + angle + "rad)");
line.css('-o-transform', "rotate(" + angle + "rad)");
}
That is the jquery version, and in this iteration I have no IE requirement so I ignore it. I could be adapted from the original function pretty easily.

The class
function getXY(evt, element) {
var rect = element.getBoundingClientRect();
var scrollTop = document.documentElement.scrollTop ? document.documentElement.scrollTop : document.body.scrollTop;
var scrollLeft = document.documentElement.scrollLeft ? document.documentElement.scrollLeft : document.body.scrollLeft;
var elementLeft = rect.left + scrollLeft;
var elementTop = rect.top + scrollTop;
x = evt.pageX - elementLeft;
y = evt.pageY - elementTop;
return { x: x, y: y };
}
var LineDrawer = {
LineHTML: `<div style="cursor: pointer;transform-origin:center; position:absolute;width:200px;height:2px; background-color:blue"></div>`,
isDown: false,
pStart: {},
pCurrent :{},
containerID: "",
JLine: {},
angle: 0,
afterLineCallback: null,
Init: function (containerID, afterLineCallback) {
LineDrawer.containerID = containerID;
LineDrawer.afterLineCallback = afterLineCallback;
LineDrawer.JLine = $(LineDrawer.LineHTML).appendTo("#" + LineDrawer.containerID);
LineDrawer.JLine.css("transform-origin", "top left");
LineDrawer.JLine.hide();
//LineDrawer.JLine.draggable({ containment: "#" + LineDrawer.containerID });
$("#" + LineDrawer.containerID).mousedown(LineDrawer.LineDrawer_mousedown);
$("#" + LineDrawer.containerID).mousemove(LineDrawer.LineDrawer_mousemove);
$("#" + LineDrawer.containerID).mouseup(LineDrawer.LineDrawer_mouseup);
},
LineDrawer_mousedown: function (e) {
if (e.target === LineDrawer.JLine[0]) return false;
LineDrawer.isDown = true;
let p = LineDrawer.pStart = getXY(e, e.target);
LineDrawer.JLine.css({ "left": p.x, "top": p.y, "width": 1});
LineDrawer.JLine.show();
},
LineDrawer_mousemove: function (e) {
if (!LineDrawer.isDown) return;
LineDrawer.pCurrent = getXY(e, document.getElementById("jim"));
let w = Math.sqrt(((LineDrawer.pStart.x - LineDrawer.pCurrent.x) * (LineDrawer.pStart.x - LineDrawer.pCurrent.x)) + ((LineDrawer.pStart.y - LineDrawer.pCurrent.y) * (LineDrawer.pStart.y - LineDrawer.pCurrent.y)));
LineDrawer.JLine.css("width", w - 2);
LineDrawer.angle = Math.atan2((LineDrawer.pStart.y - LineDrawer.pCurrent.y), (LineDrawer.pStart.x - LineDrawer.pCurrent.x)) * (180.0 / Math.PI);
//the below ensures that angle moves from 0 to -360
if (LineDrawer.angle < 0) {
LineDrawer.angle *= -1;
LineDrawer.angle += 180;
}
else LineDrawer.angle = 180 - LineDrawer.angle;
LineDrawer.angle *= -1;
LineDrawer.JLine.css("transform", "rotate(" + LineDrawer.angle + "deg");
},
LineDrawer_mouseup: function (e) {
LineDrawer.isDown = false;
if (LineDrawer.afterLineCallback == null || LineDrawer.afterLineCallback == undefined) return;
LineDrawer.afterLine(LineDrawer.angle, LineDrawer.pStart, LineDrawer.pCurrent);
},
};
Usage:
var ECApp = {
start_action: function () {
LineDrawer.Init("jim", ECApp.afterLine);
},
afterLine(angle, pStart, pEnd) {
//$("#angle").text("angle : " + angle);
let disp = "angle = " + angle;
disp += " Start = " + JSON.stringify(pStart) + " End = " + JSON.stringify(pEnd);
//alert(disp);
$("#angle").text("angle : " + disp);
}
}
$(document).ready(ECApp.start_action);
HTML
<div class="row">
<div class="col">
<div id="jim" style="position:relative;width:1200px;height:800px;background-color:lightblue;">
</div>
</div>