Small SVG app - JavaScript-to-HTML architecture?
I am on my path learning JavaScript and SVG and recently I was working on this little widget where its user would "drag & drop" various arbitrary SVG paths into canvas space and then double click and manipulate those further.
In my previous question I got very decent reply as to how to code actual draggables in SVG with good mouse handlers/listeners.
Now I am blocked by lack of understanding on how does JavaScript "talks" to HTML?
In this example below as I see it:
- we generated 6 javascript objects "from" HTML elements.
- these 6 shapes sort of turned into interactive elements and now can be dragged
- but when I attempt to doubleclick such a shape using that Select(elem) function - I can't access the pathPoints property. I guess I understand that still the HTML element and the js object are not really linked together or something.
- Can someone hint me - what am I missing here?
- How do I learn such things in broad sense, what terms I should google? "organizing javascript" "html to javascript binding". I want to learn these things and not even sure how these are called..
var selectedShape = null;
var src = document.querySelectorAll(".inventory");
for (var h = 0; h < src.length; h++) {
var o = new Draggable(src[h]);
inventory[h] = o; //not sure://
}
function Draggable(elem) {
this.target = elem
this.clickPoint = this.target.ownerSVGElement.createSVGPoint()
this.lastMove = this.target.ownerSVGElement.createSVGPoint()
this.currentMove = this.target.ownerSVGElement.createSVGPoint()
this.dpath = this.target.getAttribute("d")
this.subclass = this.target.getAttribute("subclass")
this.pathPoints = parsePathToPoints(this.dpath, this.subclass)
this.target.addEventListener("dblclick", this)
this.target.addEventListener("mousedown", this)
this.handleEvent = function(evt) {
switch (evt.type) {
case 'mousedown':
evt.preventDefault()
this.clickPoint = globalToLocalCoords(evt.clientX, evt.clientY)
this.target.classList.add("dragged")
this.target.ownerSVGElement.addEventListener("mousemove", this.move)
this.target.ownerSVGElement.addEventListener("mouseup", this.endMove)
//this.target.setAttribute("pointer-events", "all")
// bummer - tried all I could but if I use the line above - dblclick is no longer recognized/
break;
case 'dblclick':
evt.preventDefault()
if (selectedShape) {
if (selectedShape != this.target) {
selectedShape.classList.remove("selected")
this.target.classList.add("selected")
selectedShape = elem;
} else {
return;
}
} else {
selectedShape = elem
this.target.classList.add("selected")
}
Select(this.target);
break;
}
}
this.move = function(evt) {
evt.preventDefault()
var p = globalToLocalCoords(evt.clientX, evt.clientY)
this.currentMove.x = this.lastMove.x + (p.x - this.clickPoint.x)
this.currentMove.y = this.lastMove.y + (p.y - this.clickPoint.y)
this.target.setAttribute("transform", "translate(" + this.currentMove.x + "," + this.currentMove.y + ")")
}.bind(this)
this.endMove = function(evt) {
this.lastMove.x = this.currentMove.x
this.lastMove.y = this.currentMove.y
this.target.classList.remove("dragged")
this.target.setAttribute("pointer-events", "all")
this.target.ownerSVGElement.removeEventListener("mousemove", this.move)
this.target.ownerSVGElement.removeEventListener("mouseup", this.endMove)
}.bind(this)
function globalToLocalCoords(x, y) {
var p = elem.ownerSVGElement.createSVGPoint()
var m = elem.parentNode.getScreenCTM()
p.x = x
p.y = y
return p.matrixTransform(m.inverse())
}
}
function Select(elem) {
console.log(elem.pathPoints);
}
function parsePathToPoints(d, sub) {
var darray = [];
var pathPoints = {};
switch (sub) {
case 'circle':
darray = d.replace(/M|A|Z/g, "").replace(/,/g, " ").split(" ").map(Number);
pathPoints.p0 = {
"x": darray[0],
"y": darray[1]
};
pathPoints.p1 = {
"x": darray[0] + darray[2],
"y": darray[1] - darray[3]
};
pathPoints.p2 = {
"x": darray[7],
"y": darray[8]
};
pathPoints.p3 = {
"x": darray[0] + darray[2],
"y": darray[1] + darray[3]
};
pathPoints.p4 = {
"x": darray[2],
"y": darray[3]
}; // = radius used in the circle path
return pathPoints;
break;
case 'curve4':
darray = d.replace(/M|Q/g, "").replace(/,/g, " ").split(" ").map(Number);
for (i = 0, j = 1, o = 9; i < darray.length - 2; i += 2, j += 2, o++) {
pathPoints["p" + (o - 9)] = {
"x": darray[i],
"y": darray[j]
};
};
return pathPoints;
break;
case 'curve3':
darray = d.replace(/M|Q/g, "").replace(/,/g, " ").split(" ").map(Number)
for (i = 0, j = 1, o = 9; i < darray.length; i += 2, j += 2, o++) {
pathPoints["p" + (o - 9)] = {
"x": darray[i],
"y": darray[j]
};
}
return pathPoints;
break;
case 'curve2':
darray = d.replace(/M|Q/g, "").replace(/,/g, " ").split(" ").map(Number);
for (i = 0, j = 1, o = 9; i < darray.length; i += 2, j += 2, o++) {
pathPoints["p" + (o - 9)] = {
"x": darray[i],
"y": darray[j]
};
}
return pathPoints;
break;
case 'curve1':
darray = d.replace(/M|Q/g, "").replace(/,/g, " ").split(" ").map(Number);
for (i = 0, j = 1, o = 9; i < darray.length; i += 2, j += 2, o++) {
pathPoints["p" + (o - 9)] = {
"x": darray[i],
"y": darray[j]
};
}
return pathPoints;
break;
case 'cubic':
darray = d.replace(/M|C/g, "").replace(/,/g, " ").split(" ").map(Number);
for (i = 0, j = 1, o = 9; i < darray.length; i += 2, j += 2, o++) {
pathPoints["p" + (o - 9)] = {
"x": darray[i],
"y": darray[j]
};
}
return pathPoints;
break;
}
}
function pointsToPath(pathPoints, pathSubclass) {
console.log("joining " + pathPoints + "for a " + pathSubclass);
}html,
body {
margin: 0;
padding: 0;
border: 0;
overflow: hidden;
background-color: #fff;
}
svg {
position: fixed;
top: 0%;
left: 0%;
width: 100%;
height: 100%;
}
.inventory {
fill: transparent;
stroke: black;
cursor: move;
}
.dragged {
fill: transparent;
stroke: green;
cursor: move;
}
.selected {
fill: transparent;
stroke: red;
cursor: move;
}
path {
stroke-width: 3;
stroke: #000;
stroke-linecap: round;
}
path.fill {
fill: #3ff;
}
#canvasBackground {
fill: lightgrey;
}
#inventoryBackground {
fill: grey;
}