How can I add undo/redo functionalities in html canvas - javascript

I'm facing a problem with my HTML canvas project when I want to add undo/redo functionality, the idea is to merge this solution:
How to display a Canvas in a Bootstrap Modal
with this one:
https://codepen.io/abidibo/pen/rmGBc
this is my HTML code (bootstrap modal by the way)
<div id="bodyChartModal" class="modal fade bd-example-modal-xl" tabindex="-1" role="dialog" aria-labelledby="myExtraLargeModalLabel" aria-hidden="true">
<div class="modal-dialog modal-xl" role="document">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title" id="myExtraLargeModalLabel">Extra Large</h5>
<button type="button" class="close" data-dismiss="modal" aria-label="Close">
<svg aria-hidden="true" xmlns="http://www.w3.org/2000/svg" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="feather feather-x"><line x1="18" y1="6" x2="6" y2="18"></line><line x1="6" y1="6" x2="18" y2="18"></line></svg>
</button>
</div>
<div class="modal-body">
<div class="all-body-chart-buttons">
<div>
<button id="btnDraw" class="btn" style="width: 80px; height: 70px;"><i class="fas fa-pencil-alt" style="font-size: 40px; color: black;"></i></button>
<button id="btnEraser" class="btn" style="width: 80px; height: 70px;"><i class="fas fa-eraser" style="font-size: 40px; color: black;"></i></button>
</div>
<div>
<button id="btnLargeWithLine" class="btn" style="width: 80px; height: 70px;"><i class="fas fa-circle" style="font-size: 40px; color: black;"></i></button>
<button id="btnMediumWithLine" class="btn" style="width: 80px; height: 70px;"><i class="fas fa-circle" style="font-size: 20px; color: black;"></i></button>
</div>
<div>
<button id="btnSmallWithLine" class="btn" style="width: 80px; height: 70px;"><i class="fas fa-circle" style="font-size: 10px; color: black;"></i></button>
<button id="btnBlackColor" class="btn" style="width: 80px; height: 70px;"><i class="fas fa-square" style="font-size: 40px; color: black;"></i></button>
</div>
<div>
<button id="btnRedColor" class="btn" style="width: 80px; height: 70px;"><i class="fas fa-square" style="font-size: 40px; color: #9f3631;"></i></button>
<button id="btnBlueColor" class="btn" style="width: 80px; height: 70px;"><i class="fas fa-square" style="font-size: 40px; color: #00c1ca;"></i></button>
</div>
<div>
<button id="btnUndo" class="btn" style="width: 80px; height: 70px;"><i class="fas fa-undo" style="font-size: 40px; color: black;"></i></button>
<button id="btnRedo" class="btn" style="width: 80px; height: 70px;"><i class="fas fa-redo" style="font-size: 40px; color: black;"></i></button>
</div>
<div>
<button id="btnClear" class="btn" style="width: 80px; height: 70px;"><i class="fas fa-times" style="font-size: 40px; color: black;"></i></button>
</div>
</div>
<div class="canvas-box">
<canvas id="myCanvas" width="750" height="480" style="border:1px solid #000000;"></canvas>
</div>
</div>
<div class="modal-footer">
<button class="btn" data-dismiss="modal"><i class="flaticon-cancel-12"></i> Discard</button>
<button type="button" class="btn btn-primary">Save</button>
</div>
</div>
</div>
</div>
this is my CSS code
#myCanvas{
background: transparent;
}
.canvas-box {
float: right;
margin-right: 5%;
display: inline-block;
background: url("/images/body-chart-image.png");
background-size: cover;
}
.all-body-chart-buttons{
float: left;
}
And this is my Javascript code
<script>
class Signature {
constructor() {
this.redo_list = [];
this.undo_list = [];
this.img = new Image();
this.eraser = false;
this.color = "#000000";
this.sign = false;
this.begin_sign = false;
this.width_line = 5;
this.canvas = document.getElementById('myCanvas');
this.offsetLeft = this.canvas.offsetLeft;
this.offsetTop = this.canvas.offsetTop;
this.context = this.canvas.getContext('2d');
this.context.lineJoin = 'round';
this.context.lineCap = 'round';
this.whenMouseDown();
this.whenMouseUp();
this.whenMouseMove();
this.createSignature();
this.clearCanvas();
this.resetCanvas();
this.changeColorToRed();
this.changeColorToBlack();
this.changeColorToBlue();
this.changeWithLineToSmall();
this.changeWithLineToMedium();
this.changeWithLineToLarge();
this.erase();
this.draw();
this.undo();
this.redo();
this.undoEvent();
this.redoEvent();
}
updateMousePosition(mX, mY) {
let rect = this.canvas.getBoundingClientRect();
let scaleX = this.canvas.width / rect.width;
let scaleY = this.canvas.height / rect.height;
this.cursorX = (mX - rect.left) * scaleX;
this.cursorY = (mY - rect.top) * scaleY;
}
whenMouseDown() {
document.addEventListener("mousedown", ({
pageX,
pageY
}) => {
this.sign = true;
this.updateMousePosition(pageX, pageY);
this.context.beginPath();
this.context.moveTo(this.cursorX, this.cursorY);
this.context.lineTo(this.cursorX, this.cursorY);
this.context.strokeStyle = this.color;
this.context.lineWidth = this.width_line;
this.context.stroke();
})
}
whenMouseUp() {
document.addEventListener("mouseup", () => {
this.sign = false;
this.begin_sign = false;
})
}
whenMouseMove() {
this.canvas.addEventListener('mousemove', ({
pageX,
pageY
}) => {
if (this.sign) {
this.updateMousePosition(pageX, pageY);
this.createSignature();
}
})
}
createSignature() {
if (this.erazer){
this.context.globalCompositeOperation = 'destination-out';
}
else{
this.context.globalCompositeOperation = 'source-over';
}
if (!this.begin_sign) {
this.context.beginPath();
this.context.moveTo(this.cursorX, this.cursorY);
this.redo_list = [];
this.undo_list.push(this.canvas.toDataURL());
this.begin_sign = true;
} else {
this.context.lineTo(this.cursorX, this.cursorY);
this.context.strokeStyle = this.color;
this.context.lineWidth = this.width_line;
this.context.stroke();
}
}
clearCanvas() {
this.context.clearRect(0, 0, this.canvas.width, this.canvas.height);
}
changeColorToRed() {
document.getElementById("btnRedColor").addEventListener("click", () => {
this.color = "#9f3631";
})
}
changeColorToBlack() {
document.getElementById("btnBlackColor").addEventListener("click", () => {
this.color = "#000000";
})
}
changeColorToBlue() {
document.getElementById("btnBlueColor").addEventListener("click", () => {
this.color = "#00c1ca";
})
}
changeWithLineToSmall(){
document.getElementById("btnSmallWithLine").addEventListener("click", () => {
this.width_line = 5;
})
}
changeWithLineToMedium(){
document.getElementById("btnMediumWithLine").addEventListener("click", () => {
this.width_line = 10;
})
}
changeWithLineToLarge(){
document.getElementById("btnLargeWithLine").addEventListener("click", () => {
this.width_line = 20;
})
}
erase(){
document.getElementById("btnEraser").addEventListener("click", () => {
this.erazer = true;
})
}
draw(){
document.getElementById("btnDraw").addEventListener("click", () => {
this.erazer = false;
this.width_line = 5;
})
}
resetCanvas() {
document.getElementById("btnClear").addEventListener("click", () => {
this.context.globalCompositeOperation = 'source-over';
this.erazer = false;
this.clearCanvas();
})
}
undo(){
if (this.undo_list.length){
this.redo_list.push(this.canvas.toDataURL());
var restore_state = this.undo_list;
var img = this.img.src = restore_state;
var width = this.canvas.width;
var height = this.canvas.height;
img.onload = function() {
document.getElementById('myCanvas').getContext('2d').clearRect(0, 0, width, height);
document.getElementById('myCanvas').getContext('2d').drawImage(img, 0, 0, width, height, 0, 0, width, height);
}
}
}
redo(){
if(this.redo_list.length){
this.undo_list.push(this.canvas.toDataURL());
var restore_state = this.redo_list;
var img = this.img.src = restore_state;
var width = this.canvas.width;
var height = this.canvas.height;
img.onload = function() {
document.getElementById('myCanvas').getContext('2d').clearRect(0, 0, width, height);
document.getElementById('myCanvas').getContext('2d').drawImage(img, 0, 0, width, height, 0, 0, width, height);
}
}
}
undoEvent() {
document.getElementById("btnUndo").addEventListener("click", () => {
this.undo();
})
}
redoEvent() {
document.getElementById("btnRedo").addEventListener("click", () => {
this.redo();
})
}
}
document.addEventListener("DOMContentLoaded", event => {
new Signature();
});
</script>
All the functionalities working fine except undo and redo

Related

Click on an fabricjs element is not recognized

I am trying to build a simple editor using fabricjs.
I did the following:
<!DOCTYPE html>
<html lang="en">
<head>
<link href="https://cdn.jsdelivr.net/npm/bootstrap#5.2.0-beta1/dist/css/bootstrap.min.css" rel="stylesheet" />
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap-icons#1.9.0/font/bootstrap-icons.css" />
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.1/css/all.min.css">
<style>
html,
body {
height: 100%;
width: 100%;
padding: 0;
margin: 0;
}
body {
touch-action: none;
background-image: linear-gradient(to bottom left, rgb(214, 240, 201) 10%, rgba(255, 231, 191, 1) 80%);
-webkit-user-select: none;
-moz-user-select: -moz-none;
-ms-user-select: none;
user-select: none;
}
.input-group {
padding: 4px;
}
.canvas-container {
margin: 0 auto;
width: 100%;
overflow: hidden;
background: url(./transparent.png);
background-size: 15px 15px;
box-shadow: rgba(60, 64, 67, 0.3) 0px 1px 2px 0px, rgba(60, 64, 67, 0.15) 0px 1px 3px 1px;
}
.actived {
background: #fff9a8;
}
.list-group {
line-height: 35px;
}
.svg-icon {
width: 1em;
height: 1em;
}
.svg-icon path,
.svg-icon polygon,
.svg-icon rect {
fill: #4691f6;
}
.svg-icon circle {
stroke: #4691f6;
stroke-width: 1;
}
.fl {
float: left;
}
.fr {
float: right;
}
.input-group-text {
background-color: #f4f4f4;
}
.list-group-item {
padding: 2px 10px;
;
cursor: pointer;
}
.list-group {
border-radius: 0;
text-align: left;
}
</style>
</head>
<body>
<div class="container-fluid h-100">
<div class="row h-100">
<div class="col-sm-3 border-end text-center h-100 overflow-scroll bg-light py-3">
<hr>
<div class="form-floating w-100 mb-3 tour5">
<h6 class="mb-3">Add Element</h6>
<button class="btn btn-outline-primary" onclick="addText();" data-toggle="tooltip" data-placement="top" title="" data-bs-original-title="Add Text" aria-label="Add Text"><i
class="fa fa-font"></i></button>
<button class="btn btn-outline-primary" data-toggle="tooltip" data-placement="top" title="" onclick=" canvas.add(new fabric.Circle({ name: genNextName(), originX:'center', originY:'center', radius: 30, fill: '#000', top: 100, left: 100 }));" data-bs-original-title="Add Circle"
aria-label="Add Circle"><i
class="fa fa-circle"></i></button>
<button class="btn btn-outline-primary" data-toggle="tooltip" data-placement="top" title="" onclick=" canvas.add(new fabric.Triangle({ name: genNextName(), originX:'center', originY:'center', height:100, width:100, fill: '#000', top: 100, left: 100 }));"
data-bs-original-title="Add Triangle">
<svg aria-hidden="true" focusable="false" data-prefix="fas" data-icon="triangle" role="img"
xmlns="http://www.w3.org/2000/svg" viewBox="0 0 576 512" class=""
style="height: 16px;top: 9px;">
<path fill="currentColor"
d="M329.6 24c-18.4-32-64.7-32-83.2 0L6.5 440c-18.4 31.9 4.6 72 41.6 72H528c36.9 0 60-40 41.6-72l-240-416z"
class=""></path>
</svg>
</button>
</div>
<hr>
</div>
<div class="col-sm-6 my-auto py-4 overflow-hidden">
<div class="canvas-container" style="width: 329px; height: 329px; position: relative; user-select: none;"><canvas id="c" class="lower-canvas" width="329" height="329" style="position: absolute; width: 329px; height: 329px; left: 0px; top: 0px; touch-action: none; user-select: none;"></canvas><canvas class="upper-canvas " width="329" height="329" style="position: absolute; width: 329px; height: 329px; left: 0px; top: 0px; touch-action: manipulation; user-select: none; cursor: default;"></canvas>
</div>
</div>
<div class="col-sm-3 border-start py-3 h-100 overflow-scroll bg-light text-center">
<form class="form-inline pt-4" id="f" onsubmit="return false;" style="display: none;">
<div class="form-floating w-100 mb-4" style="">
<textarea type="text" class="form-control form-control-sm" name="text" oninput="canvas.getActiveObject().set({'text':this.value}); canvas.renderAll();" onmouseover="this.style.height = (this.scrollHeight)+'px';" rows="10" autocomplete="off"></textarea>
<label for="floatingInput" class="lable-sm">Text</label>
</div>
<div class="input-group input-group-sm mb-3 w-100 tour13">
<span class="input-group-text" id="inputGroup-sizing-sm">MaxHeight to Fit Text</span>
<input type="number" class="form-control" name="maxHeight" onkeyup="hide_mh_box(); show_mh_box();" onblur="hide_mh_box();" onfocus="show_mh_box();" autocomplete="off">
</div>
</form>
</div>
</div>
</div>
<script src="https://cdn.jsdelivr.net/npm/bootstrap#5.2.0-beta1/dist/js/bootstrap.bundle.min.js"></script>
<script src="https://code.jquery.com/jquery-3.6.0.js"></script>
<script src="https://code.jquery.com/ui/1.13.1/jquery-ui.js"></script>
<script src="https://unpkg.com/fabric#5.2.1/dist/fabric.min.js"></script>
<script src="https://rawcdn.githack.com/lyzerk/fabric-history/8c223cbdc8305307b4a8f8710f97da54d9146ffa/src/index.js"></script>
<script src="https://rawgit.com/fabricjs/fabric.js/master/lib/centering_guidelines.js"></script>
<script src="https://rawgit.com/fabricjs/fabric.js/master/lib/aligning_guidelines.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/webfont/1.5.10/webfont.js"></script>
<script>
var canvas;
var apiUrl;
var startedLoadingFamilies = false;
var to;
var scale;
fabric.Text.prototype.set({
_getNonTransformedDimensions() {
return new fabric.Point(this.width, this.height).scalarAdd(this.padding);
},
_calculateCurrentDimensions() {
return fabric.util.transformPoint(this._getTransformedDimensions(), this.getViewportTransform(), true);
}
});
function fitCanvas(w, h) {
var scaleW = (document.querySelectorAll(".col-sm-6")[0].offsetWidth - 100) / w;
var scaleH = (document.querySelectorAll("body")[0].offsetHeight - 100) / h;
scale = Math.min(scaleH, scaleW);
if (scale > 1) {
scale = 1;
}
canvas.setZoom(scale);
canvas.setWidth(w * scale);
canvas.setHeight(h * scale);
initAligningGuidelines(canvas);
initCenteringGuidelines(canvas);
canvas.renderAll();
console.log("finished!!");
}
(function() {
canvas = new fabric.Canvas('c', {
allowTouchScrolling: true
});
WebFont.load({
google: {
families: ["Inter:200"]
},
active: function() {
canvas.loadFromJSON({
"height": "500",
"width": "500",
"edit": "yes",
"objects": [],
"backgroundImage": {
"crossOrigin": "anonymous"
}
}, function() {
fitCanvas(500, 500);
})
}
});
canvas.on('before:render', function(opt) {
canvas.getObjects().map(function(o, i) {
if (o.type.toLowerCase() == "textbox") {
var maxH = (o.maxHeight) ? (o.maxHeight) : (canvas.height);
o.set({
'maxHeight': maxH
});
if (o.fontSize > 0 && (maxH > o.fontSize)) {
while (o.height > maxH) {
o.set({
'fontSize': o.fontSize - 1
});
}
}
}
if (o.circleFrame) {
o.set({
clipPath: new fabric.Circle({
radius: o.width / 2,
originX: 'center',
originY: 'center'
})
});
}
if ((o.rx || o.ry) && o.type == "image") {
let rx = (o.rx || 0);
let ry = (o.ry || 0);
o.set({
clipPath: new fabric.Rect({
rx: rx,
ry: ry,
height: o.height,
width: o.width,
originX: 'center',
originY: 'center'
})
});
}
});
});
})();
</script>
<script>
fabric.Object.prototype.objectCaching = false;
function changeDim() {
fitCanvas($("#widthC").val(), $("#heightC").val());
}
function setCanvasBI(src, o = "1") {
if (!src) {
src = $("#canvasBI").val();
}
if (src.length == 0) {
src = new fabric.Image('');
}
canvas.setBackgroundImage(src, canvas.renderAll.bind(canvas), {
opacity: o
});
}
(function() {
$(document).on("mouseenter", "[data-label]", function() {
$("#font-search").val($(this).data("label"));
loadFont($(this).data("label"));
});
fabric.Canvas.prototype.getItemByAttr = function(attr, name) {
var object = null,
objects = this.getObjects();
for (var i = 0, len = this.size(); i < len; i++) {
if (objects[i][attr] && objects[i][attr] == name) {
object = objects[i];
break;
}
}
return object;
};
$("form#f").hide();
var activeObject;
$("#f input, #f select").on("input", function() {
if (["height", "width", "top", "left", "strokeWidth", "charSpacing"].includes(this.name)) {
canvas.getActiveObject().set(this.name, parseFloat(this.value)).setCoords();
} else {
canvas.getActiveObject().set(this.name, this.value).setCoords();
}
canvas.renderAll();
});
canvas.preserveObjectStacking = true;
fabric.Object.prototype.toObject = (function(toObject) {
return function() {
return fabric.util.object.extend(toObject.call(this), {
name: this.name,
text: this.text
});
};
})(fabric.Object.prototype.toObject);
canvas.on('object:scaling', function(e) {
if (e.target.toObject().type != "image" && e.target.toObject().type != "circle") {
e.target.set({
width: e.target.width * e.target.scaleX,
height: e.target.height * e.target.scaleY,
scaleX: 1,
scaleY: 1
})
}
});
canvas.on('object:modified', function(opt) {
document.body.style.cursor = 'progress';
});
canvas.on("after:render", function() {
canvas.includeDefaultValues = false;
canvas.toObject().objects.forEach(function(layer, id) {
if (typeof layer.name !== 'undefined') {
canvas.getItemByAttr(`name`, layer.name).set({
"name": String.fromCharCode(65 + id).toLowerCase()
})
var actived = '';
if (canvas.getActiveObject()) {
actived = (canvas.getActiveObject().name == layer.name) ? " actived" : "";
}
}
});
document.body.style.cursor = 'default'
});
canvas.on("selection:created", function(obj) {
if ("image" == obj.target.type) {
canvas.getActiveObject().setControlsVisibility({
mb: false,
ml: false,
mt: false,
mr: false
});
}
$("form#f input[type!='hidden'], #f select").parent().hide();
$("form#f").hide();
canvas.renderAll();
showForm();
});
canvas.on("selection:updated", function(obj) {
if ("image" == obj.target.type) {
canvas.getActiveObject().setControlsVisibility({
mb: false,
ml: false,
mt: false,
mr: false
});
}
canvas.renderAll();
$("form#f").hide();
$("form#f input[type!='hidden'] , #f select, #f textarea").parent().hide();
showForm();
});
canvas.on("selection:cleared", function() {
canvas.renderAll();
$("form#f").hide();
$("form#f input[type!='hidden'], #f select, #f textarea").parent().hide();
});
canvas.hoverCursor = 'default';
canvas.on('mouse:over', function(e) {
if (e.target) {
e.target._renderControls(canvas.contextTop, {
hasControls: false
})
}
});
canvas.on('mouse:out', function(e) {
canvas.clearContext(canvas.contextTop);
});
canvas.on('mouse:down', function(e) {
canvas.clearContext(canvas.contextTop);
});
function showForm() {
$("form#f").show();
activeObject = canvas.getActiveObject();
var v;
for (i in activeObject) {
v = activeObject[i];
if (typeof v != "undefined") {
$("textarea[name='" + i + "']").val(v).parent().show();
$("input[name='" + i + "']").val(v).parent().show();
$("select[name='" + i + "']").val(v).parent().show();
}
}
}
addText = function() {
var text = new fabric.Textbox("Edit this Text", {
name: genNextName(),
left: canvas.getWidth() / canvas.getZoom() / 2,
top: canvas.getHeight() / canvas.getZoom() / 2,
width: (canvas.getWidth() / canvas.getZoom()) / 2,
fill: "#000000",
originX: "center",
originY: "center",
fontFamily: "Inter",
fontWeight: 400,
fontSize: 60,
padding: 20
});
text.setControlsVisibility({
mt: false,
mb: false,
ml: true,
mr: true,
tl: true,
tr: true,
bl: true,
br: true
});
canvas.add(text);
canvas.setActiveObject(text);
canvas.renderAll();
};
})();
function hide_mh_box() {
canvas.remove(canvas.getItemByAttr("isBB", true));
}
function show_mh_box() {
var h = parseInt($("[name=maxHeight]").val());
var n = new fabric.Rect({
top: canvas.getActiveObject().get('top'),
left: canvas.getActiveObject().get('left'),
width: canvas.getActiveObject().get('width'),
height: h,
originX: canvas.getActiveObject().get('originX'),
originY: canvas.getActiveObject().get('originY'),
angle: canvas.getActiveObject().get('angle'),
opacity: 1,
strokeWidth: 2,
stroke: "#FF00FF",
fill: "rgba(0,0,0,0)",
evented: !1,
isBB: true
});
canvas.add(n);
canvas.renderAll();
}
var visited = [];
</script>
<script>
function genNextName() {
canvas.renderAll();
var total = canvas.getObjects().length;
return String.fromCharCode(65 + total).toLowerCase()
}
</script>
</body>
</html>
When I click on an element f.ex. the triangle it is added to the canvas. When I click on the added triangle a menu on the right should go up. However, the element does not get selected.
Any suggestions what I am doing wrong?
I appreciate your replies!

you have second canvas element next to your canvas, it prevents from clicking on first canvas element, removing this second canvas solves this issue
<canvas class="upper-canvas " width="329" height="329" style="position: absolute; width: 329px; height: 329px; left: 0px; top: 0px; touch-action: manipulation; user-select: none; cursor: default;"></canvas>
<!DOCTYPE html>
<html lang="en">
<head>
<link href="https://cdn.jsdelivr.net/npm/bootstrap#5.2.0-beta1/dist/css/bootstrap.min.css" rel="stylesheet" />
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap-icons#1.9.0/font/bootstrap-icons.css" />
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.1/css/all.min.css">
<style>
html,
body {
height: 100%;
width: 100%;
padding: 0;
margin: 0;
}
body {
touch-action: none;
background-image: linear-gradient(to bottom left, rgb(214, 240, 201) 10%, rgba(255, 231, 191, 1) 80%);
-webkit-user-select: none;
-moz-user-select: -moz-none;
-ms-user-select: none;
user-select: none;
}
.input-group {
padding: 4px;
}
.canvas-container {
margin: 0 auto;
width: 100%;
overflow: hidden;
background: url(./transparent.png);
background-size: 15px 15px;
box-shadow: rgba(60, 64, 67, 0.3) 0px 1px 2px 0px, rgba(60, 64, 67, 0.15) 0px 1px 3px 1px;
}
.actived {
background: #fff9a8;
}
.list-group {
line-height: 35px;
}
.svg-icon {
width: 1em;
height: 1em;
}
.svg-icon path,
.svg-icon polygon,
.svg-icon rect {
fill: #4691f6;
}
.svg-icon circle {
stroke: #4691f6;
stroke-width: 1;
}
.fl {
float: left;
}
.fr {
float: right;
}
.input-group-text {
background-color: #f4f4f4;
}
.list-group-item {
padding: 2px 10px;
;
cursor: pointer;
}
.list-group {
border-radius: 0;
text-align: left;
}
</style>
</head>
<body>
<div class="container-fluid h-100">
<div class="row h-100">
<div class="col-sm-3 border-end text-center h-100 overflow-scroll bg-light py-3">
<hr>
<div class="form-floating w-100 mb-3 tour5">
<h6 class="mb-3">Add Element</h6>
<button class="btn btn-outline-primary" onclick="addText();" data-toggle="tooltip" data-placement="top" title="" data-bs-original-title="Add Text" aria-label="Add Text"><i
class="fa fa-font"></i></button>
<button class="btn btn-outline-primary" data-toggle="tooltip" data-placement="top" title="" onclick=" canvas.add(new fabric.Circle({ name: genNextName(), originX:'center', originY:'center', radius: 30, fill: '#000', top: 100, left: 100 }));" data-bs-original-title="Add Circle"
aria-label="Add Circle"><i
class="fa fa-circle"></i></button>
<button class="btn btn-outline-primary" data-toggle="tooltip" data-placement="top" title="" onclick=" canvas.add(new fabric.Triangle({ name: genNextName(), originX:'center', originY:'center', height:100, width:100, fill: '#000', top: 100, left: 100 }));"
data-bs-original-title="Add Triangle">
<svg aria-hidden="true" focusable="false" data-prefix="fas" data-icon="triangle" role="img"
xmlns="http://www.w3.org/2000/svg" viewBox="0 0 576 512" class=""
style="height: 16px;top: 9px;">
<path fill="currentColor"
d="M329.6 24c-18.4-32-64.7-32-83.2 0L6.5 440c-18.4 31.9 4.6 72 41.6 72H528c36.9 0 60-40 41.6-72l-240-416z"
class=""></path>
</svg>
</button>
</div>
<hr>
</div>
<div class="col-sm-6 my-auto py-4 overflow-hidden">
<div class="canvas-container" style="width: 329px; height: 329px; position: relative; user-select: none;"><canvas id="c" class="lower-canvas" width="329" height="329" style="position: absolute; width: 329px; height: 329px; left: 0px; top: 0px; touch-action: none; user-select: none;"></canvas>
</div>
</div>
<div class="col-sm-3 border-start py-3 h-100 overflow-scroll bg-light text-center">
<form class="form-inline pt-4" id="f" onsubmit="return false;" style="display: none;">
<div class="form-floating w-100 mb-4" style="">
<textarea type="text" class="form-control form-control-sm" name="text" oninput="canvas.getActiveObject().set({'text':this.value}); canvas.renderAll();" onmouseover="this.style.height = (this.scrollHeight)+'px';" rows="10" autocomplete="off"></textarea>
<label for="floatingInput" class="lable-sm">Text</label>
</div>
<div class="input-group input-group-sm mb-3 w-100 tour13">
<span class="input-group-text" id="inputGroup-sizing-sm">MaxHeight to Fit Text</span>
<input type="number" class="form-control" name="maxHeight" onkeyup="hide_mh_box(); show_mh_box();" onblur="hide_mh_box();" onfocus="show_mh_box();" autocomplete="off">
</div>
</form>
</div>
</div>
</div>
<script src="https://cdn.jsdelivr.net/npm/bootstrap#5.2.0-beta1/dist/js/bootstrap.bundle.min.js"></script>
<script src="https://code.jquery.com/jquery-3.6.0.js"></script>
<script src="https://code.jquery.com/ui/1.13.1/jquery-ui.js"></script>
<script src="https://unpkg.com/fabric#5.2.1/dist/fabric.min.js"></script>
<script src="https://rawcdn.githack.com/lyzerk/fabric-history/8c223cbdc8305307b4a8f8710f97da54d9146ffa/src/index.js"></script>
<script src="https://rawgit.com/fabricjs/fabric.js/master/lib/centering_guidelines.js"></script>
<script src="https://rawgit.com/fabricjs/fabric.js/master/lib/aligning_guidelines.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/webfont/1.5.10/webfont.js"></script>
<script>
var canvas;
var apiUrl;
var startedLoadingFamilies = false;
var to;
var scale;
fabric.Text.prototype.set({
_getNonTransformedDimensions() {
return new fabric.Point(this.width, this.height).scalarAdd(this.padding);
},
_calculateCurrentDimensions() {
return fabric.util.transformPoint(this._getTransformedDimensions(), this.getViewportTransform(), true);
}
});
function fitCanvas(w, h) {
var scaleW = (document.querySelectorAll(".col-sm-6")[0].offsetWidth - 100) / w;
var scaleH = (document.querySelectorAll("body")[0].offsetHeight - 100) / h;
scale = Math.min(scaleH, scaleW);
if (scale > 1) {
scale = 1;
}
canvas.setZoom(scale);
canvas.setWidth(w * scale);
canvas.setHeight(h * scale);
initAligningGuidelines(canvas);
initCenteringGuidelines(canvas);
canvas.renderAll();
console.log("finished!!");
}
(function() {
canvas = new fabric.Canvas('c', {
allowTouchScrolling: true
});
WebFont.load({
google: {
families: ["Inter:200"]
},
active: function() {
canvas.loadFromJSON({
"height": "500",
"width": "500",
"edit": "yes",
"objects": [],
"backgroundImage": {
"crossOrigin": "anonymous"
}
}, function() {
fitCanvas(500, 500);
})
}
});
canvas.on('before:render', function(opt) {
canvas.getObjects().map(function(o, i) {
if (o.type.toLowerCase() == "textbox") {
var maxH = (o.maxHeight) ? (o.maxHeight) : (canvas.height);
o.set({
'maxHeight': maxH
});
if (o.fontSize > 0 && (maxH > o.fontSize)) {
while (o.height > maxH) {
o.set({
'fontSize': o.fontSize - 1
});
}
}
}
if (o.circleFrame) {
o.set({
clipPath: new fabric.Circle({
radius: o.width / 2,
originX: 'center',
originY: 'center'
})
});
}
if ((o.rx || o.ry) && o.type == "image") {
let rx = (o.rx || 0);
let ry = (o.ry || 0);
o.set({
clipPath: new fabric.Rect({
rx: rx,
ry: ry,
height: o.height,
width: o.width,
originX: 'center',
originY: 'center'
})
});
}
});
});
})();
</script>
<script>
fabric.Object.prototype.objectCaching = false;
function changeDim() {
fitCanvas($("#widthC").val(), $("#heightC").val());
}
function setCanvasBI(src, o = "1") {
if (!src) {
src = $("#canvasBI").val();
}
if (src.length == 0) {
src = new fabric.Image('');
}
canvas.setBackgroundImage(src, canvas.renderAll.bind(canvas), {
opacity: o
});
}
(function() {
$(document).on("mouseenter", "[data-label]", function() {
$("#font-search").val($(this).data("label"));
loadFont($(this).data("label"));
});
fabric.Canvas.prototype.getItemByAttr = function(attr, name) {
var object = null,
objects = this.getObjects();
for (var i = 0, len = this.size(); i < len; i++) {
if (objects[i][attr] && objects[i][attr] == name) {
object = objects[i];
break;
}
}
return object;
};
$("form#f").hide();
var activeObject;
$("#f input, #f select").on("input", function() {
if (["height", "width", "top", "left", "strokeWidth", "charSpacing"].includes(this.name)) {
canvas.getActiveObject().set(this.name, parseFloat(this.value)).setCoords();
} else {
canvas.getActiveObject().set(this.name, this.value).setCoords();
}
canvas.renderAll();
});
canvas.preserveObjectStacking = true;
fabric.Object.prototype.toObject = (function(toObject) {
return function() {
return fabric.util.object.extend(toObject.call(this), {
name: this.name,
text: this.text
});
};
})(fabric.Object.prototype.toObject);
canvas.on('object:scaling', function(e) {
if (e.target.toObject().type != "image" && e.target.toObject().type != "circle") {
e.target.set({
width: e.target.width * e.target.scaleX,
height: e.target.height * e.target.scaleY,
scaleX: 1,
scaleY: 1
})
}
});
canvas.on('object:modified', function(opt) {
document.body.style.cursor = 'progress';
});
canvas.on("after:render", function() {
canvas.includeDefaultValues = false;
canvas.toObject().objects.forEach(function(layer, id) {
if (typeof layer.name !== 'undefined') {
canvas.getItemByAttr(`name`, layer.name).set({
"name": String.fromCharCode(65 + id).toLowerCase()
})
var actived = '';
if (canvas.getActiveObject()) {
actived = (canvas.getActiveObject().name == layer.name) ? " actived" : "";
}
}
});
document.body.style.cursor = 'default'
});
canvas.on("selection:created", function(obj) {
if ("image" == obj.target?.type) {
canvas.getActiveObject().setControlsVisibility({
mb: false,
ml: false,
mt: false,
mr: false
});
}
$("form#f input[type!='hidden'], #f select").parent().hide();
$("form#f").hide();
canvas.renderAll();
showForm();
});
canvas.on("selection:updated", function(obj) {
if ("image" == obj.target?.type) {
canvas.getActiveObject().setControlsVisibility({
mb: false,
ml: false,
mt: false,
mr: false
});
}
canvas.renderAll();
$("form#f").hide();
$("form#f input[type!='hidden'] , #f select, #f textarea").parent().hide();
showForm();
});
canvas.on("selection:cleared", function() {
canvas.renderAll();
$("form#f").hide();
$("form#f input[type!='hidden'], #f select, #f textarea").parent().hide();
});
canvas.hoverCursor = 'default';
canvas.on('mouse:over', function(e) {
if (e.target) {
e.target._renderControls(canvas.contextTop, {
hasControls: false
})
}
});
canvas.on('mouse:out', function(e) {
canvas.clearContext(canvas.contextTop);
});
canvas.on('mouse:down', function(e) {
canvas.clearContext(canvas.contextTop);
});
function showForm() {
$("form#f").show();
activeObject = canvas.getActiveObject();
var v;
for (i in activeObject) {
v = activeObject[i];
if (typeof v != "undefined") {
$("textarea[name='" + i + "']").val(v).parent().show();
$("input[name='" + i + "']").val(v).parent().show();
$("select[name='" + i + "']").val(v).parent().show();
}
}
}
addText = function() {
var text = new fabric.Textbox("Edit this Text", {
name: genNextName(),
left: canvas.getWidth() / canvas.getZoom() / 2,
top: canvas.getHeight() / canvas.getZoom() / 2,
width: (canvas.getWidth() / canvas.getZoom()) / 2,
fill: "#000000",
originX: "center",
originY: "center",
fontFamily: "Inter",
fontWeight: 400,
fontSize: 60,
padding: 20
});
text.setControlsVisibility({
mt: false,
mb: false,
ml: true,
mr: true,
tl: true,
tr: true,
bl: true,
br: true
});
canvas.add(text);
canvas.setActiveObject(text);
canvas.renderAll();
};
})();
function hide_mh_box() {
canvas.remove(canvas.getItemByAttr("isBB", true));
}
function show_mh_box() {
var h = parseInt($("[name=maxHeight]").val());
var n = new fabric.Rect({
top: canvas.getActiveObject().get('top'),
left: canvas.getActiveObject().get('left'),
width: canvas.getActiveObject().get('width'),
height: h,
originX: canvas.getActiveObject().get('originX'),
originY: canvas.getActiveObject().get('originY'),
angle: canvas.getActiveObject().get('angle'),
opacity: 1,
strokeWidth: 2,
stroke: "#FF00FF",
fill: "rgba(0,0,0,0)",
evented: !1,
isBB: true
});
canvas.add(n);
canvas.renderAll();
}
var visited = [];
</script>
<script>
function genNextName() {
canvas.renderAll();
var total = canvas.getObjects().length;
return String.fromCharCode(65 + total).toLowerCase()
}
</script>
</body>
</html>

Drag'n'drop: Element not staying at its original position when I click on it

I am writing my own Drag'n'drop functionality for one of my projects and I am running into an issue. All my "draggable" elements are inside a container with display:flex. On mousedown event on one of this elements I set the position to absolute so I would be able to set the left and top properties of the element when I am dragging. Here is what I am doing:
let container = document.querySelector("#big-container")
var dragging = false;
var draggedObject;
let shiftX=0;
let shiftY=0;
document.querySelectorAll(".draggable").forEach((draggable,index) => {
draggable.style.order = index;
draggable.draggable =false;
draggable.ondragstart = ()=>{return false}
draggable.addEventListener("mousedown",ev =>{
draggedObject = draggable;
shiftX = ev.offsetX+5;
shiftY = ev.offsetY+5;
draggable.style.position = "absolute";
draggable.style.left = (ev.clientX - shiftX) + 'px';
draggable.style.top = (ev.clientY - shiftY) + 'px';
dragging = true;
let placeholder = document.createElement("div");
placeholder.id = "placeholder";
placeholder.style.order = draggable.style.order;
container.appendChild(placeholder);
})
})
document.addEventListener("mousemove", ev =>{
if(dragging){
draggedObject.style.left = ev.clientX - shiftX + 'px';
draggedObject.style.top = ev.clientY - shiftY + 'px';
}
})
document.addEventListener("mouseup",ev =>{
if(dragging){
draggedObject.style.position = 'static'
let placeholder = document.querySelector("#placeholder");
container.removeChild(placeholder);
dragging = false
}
})
/* the :not(:last-of-type(div)) is there so the console doesn't get affected */
*{
margin: 0;
padding: 0;
box-sizing: border-box;
background-color: black;
}
.draggable {
width: 90px;
height: 120px;
margin: 5px;
}
#placeholder {
width: 90px;
height: 120px;
margin: 5px;
background-color: rgba(0, 0, 0, 0.3);
border: dashed grey 5px;
}
<body draggable="false" ondragstart="return false;">
<div id = "big-container" style ="display: flex; background-color: rgb(76, 104, 95); width: 500px; height: 500px;">
<div style="background-color: rgb(204, 125, 111);" class="draggable"></div>
<div style="background-color: rgb(170, 214, 120);" class="draggable"></div>
<div style="background-color: rgb(129, 212, 167);" class="draggable"></div>
<div style="background-color: rgb(162, 137, 196);" class="draggable"></div>
</div>
</body>
What I am trying to achieve is that on mousedown the element should stay where it was and after that when I move my mouse to move the element as well.(the anchor point should be where I clicked the element)
I am doing shiftX = ev.offsetX+5; because I need to account for the element's margin.
The issue is when I click on a element(and don't move my mouse at all), you can see a little shift in the element's position. It is very minor(maybe 1 or 2px) and is not happening in all places(some zones in the element do not introduce this position shift)
Do you guys have any idea what might be causing it?

You can use getBoundingClientRect() to get the actual position.
let container = document.querySelector("#big-container");
var dragging = false;
var draggedObject;
let shiftX = 0;
let shiftY = 0;
document.querySelectorAll(".draggable").forEach((draggable, index) => {
draggable.style.order = index;
draggable.draggable = false;
draggable.ondragstart = () => {
return false;
};
draggable.addEventListener("mousedown", (ev) => {
draggedObject = draggable;
var x = draggable.getBoundingClientRect().top - 5;
var y = draggable.getBoundingClientRect().left - 5;
shiftX = ev.offsetX + 5;
shiftY = ev.offsetY + 5;
draggable.style.position = "absolute";
draggable.style.left = y + "px";
draggable.style.top = x + "px";
dragging = true;
let placeholder = document.createElement("div");
placeholder.id = "placeholder";
placeholder.style.order = draggable.style.order;
container.appendChild(placeholder);
});
});
document.addEventListener("mousemove", (ev) => {
if (dragging) {
draggedObject.style.left = ev.clientX - shiftX + "px";
draggedObject.style.top = ev.clientY - shiftY + "px";
}
});
document.addEventListener("mouseup", (ev) => {
if (dragging) {
draggedObject.style.position = "static";
let placeholder = document.querySelector("#placeholder");
container.removeChild(placeholder);
dragging = false;
}
});
* {
margin: 0;
padding: 0;
box-sizing: border-box;
background-color: black;
}
#big-container {
width: 500px;
height: 500px;
}
.draggable {
width: 90px;
height: 120px;
margin: 5px;
}
#placeholder {
width: 90px;
height: 120px;
margin: 5px;
background-color: rgba(0, 0, 0, 0.3);
border: dashed grey 5px;
}
<body draggable="false" ondragstart="return false;">
<div
id="big-container"
style="display: flex; background-color: rgb(76, 104, 95);"
>
<div
style="background-color: rgb(204, 125, 111);"
class="draggable"
></div>
<div
style="background-color: rgb(170, 214, 120);"
class="draggable"
></div>
<div
style="background-color: rgb(129, 212, 167);"
class="draggable"
></div>
<div
style="background-color: rgb(162, 137, 196);"
class="draggable"
></div>
</div>
</body>

Objects seem to be appearing behind my canvas

I'm adding objects to my canvas with the fabricjs library (1.7.21) however I am getting this odd behavior where objects are appearing to be behind the canvas. The text is either displayed as white or behind the canvas and I'm not sure why or how. What am I missing here?
var canvas = this.__canvas = new fabric.Canvas('canvas');
responsive();
window.addEventListener('resize', responsive);
function responsive() {
var width = (window.innerWidth > 0) ? window.innerWidth : screen.width;
var height = (window.innerHeight > 0) ? window.innerHeight : screen.height;
var widthn = width - 10;
var heightn = height - 10;
canvas.setDimensions({
width: widthn,
height: heightn
});
}
function clearcan() {
var txt;
if (confirm("Chuck this?")) {
console.log(canvas)
canvas.clear().renderAll();
newleft = 0;
}
}
// Add Text
function Addtext() {
var text = new fabric.IText("Tape & Type...", {
fontSize: 30,
top: 10,
left: 10,
width: 200,
height: 200,
textAlign: "center"
});
canvas.add(text);
canvas.setActiveObject(text);
text.enterEditing();
text.selectAll();
text.renderCursorOrSelection(); // or canvas.renderAll();
}
body {
background-color: #303030;
color: white;
}
canvas {
border-radius: 3px;
border: 1px solid #3030;
margin: 5px;
background-color: white;
}
.btn {
background-color: #3030;
color: white;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/1.7.21/fabric.min.js"></script>
<div class="col d-flex justify-content-center">
<div class="btn-toolbar" role="toolbar" aria-label="Toolbar with button groups">
<div class="btn-group mr-2" role="group" aria-label="First group">
<button onclick="clearcan();" type="button" class="btn btn-sm">Clear</button>
<button onclick="Addtext()"type="button" class="btn btn-sm"> Add Text</button>
</div>
</div>
</div>
<canvas id="canvas"></canvas>
Here's my JSFiddle.

Remove background-color from css which applies to both upper and lower canvas. use this
var canvas = this.__canvas = new fabric.Canvas('canvas',{
backgroundColor:'white'
});
It will make lower canvas background white.
DEMO
var canvas = this.__canvas = new fabric.Canvas('canvas',{
backgroundColor:'white'
});
responsive();
window.addEventListener('resize', responsive);
function responsive() {
var width = (window.innerWidth > 0) ? window.innerWidth : screen.width;
var height = (window.innerHeight > 0) ? window.innerHeight : screen.height;
var widthn = width - 10;
var heightn = height - 10;
canvas.setDimensions({
width: widthn,
height: heightn
});
}
function clearcan() {
var txt;
if (confirm("Chuck this?")) {
console.log(canvas)
canvas.clear().renderAll();
newleft = 0;
}
}
// Add Text
function Addtext() {
var text = new fabric.IText("Tape & Type...", {
fontSize: 30,
top: 10,
left: 10,
width: 200,
height: 200,
textAlign: "center"
});
canvas.add(text);
canvas.setActiveObject(text);
text.enterEditing();
text.selectAll();
text.renderCursorOrSelection(); // or canvas.renderAll();
}
body {
background-color: #303030;
color: white;
}
canvas {
border-radius: 3px;
border: 1px solid #3030;
margin: 5px;
//background-color: white;
}
.btn {
background-color: #3030;
color: white;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/1.7.21/fabric.min.js"></script>
<div class="col d-flex justify-content-center">
<div class="btn-toolbar" role="toolbar" aria-label="Toolbar with button groups">
<div class="btn-group mr-2" role="group" aria-label="First group">
<button onclick="clearcan();" type="button" class="btn btn-sm">Clear</button>
<button onclick="Addtext()"type="button" class="btn btn-sm"> Add Text</button>
</div>
</div>
</div>
<canvas id="canvas"></canvas>

JavaScript Progress bar don't work

This code didn't work with me just one work and when i remove script tag from html to external file didn't work i need need help to all record work and move it to external file.....................................
window.onload = function() {
var elem = document.getElementById("myBar");
var valuee = document.getElementById("bar").value;
var width = 0;
var id = setInterval(frame, 10);
function frame() {
if (width >= 100) {
clearInterval(id);
} else {
width++;
elem.style.width = width + '%';
elem.innerHTML = width * 1 + '%';
}
}
}
#myProgress {
width: 100%;
background-color: #ddd;
}
#myBar {
width: 10%;
height: 30px;
background-color: #4CAF50;
text-align: center;
line-height: 30px;
color: white;
}
<h1>JavaScript Progress Bar</h1>
<div id="myProgress">
<div id="myBar">0%</div>
<input type="hidden" id="bar" name="bar" value="60" />
</div>
<div id="myProgress">
<div id="myBar">0%</div>
<input type="hidden" id="bar" name="bar" value="60" />
</div>
<br>
<button onclick="move()">Click Me</button>

window.onload = function() {
var elem = document.getElementById("myBar");
var valuee = document.getElementById("bar").value;
var width = 0;
var id = setInterval(frame, 10);
function frame() {
if (width >= 100) {
clearInterval(id);
} else {
width++;
elem.style.width = width + '%';
elem.innerHTML = width * 1 + '%';
}
}
var elem_1 = document.getElementById("myBar_1");
var valuee_1 = document.getElementById("bar_1").value;
var width_1 = 0;
var id_1 = setInterval(frame_1, 10);
function frame_1() {
if (width_1 >= 100) {
clearInterval(id_1);
} else {
width_1++;
elem_1.style.width = width_1 + '%';
elem_1.innerHTML = width_1 * 1 + '%';
}
}
}
#myProgress,
#myProgress_1 {
width: 100%;
background-color: #ddd;
}
#myBar,
#myBar_1 {
width: 10%;
height: 30px;
background-color: #4CAF50;
text-align: center;
line-height: 30px;
color: white;
}
<h1>JavaScript Progress Bar</h1>
<div id="myProgress">
<div id="myBar">0%</div>
<input type="hidden" id="bar" name="bar" value="60" />
</div>
<div id="myProgress_1">
<div id="myBar_1">0%</div>
<input type="hidden" id="bar_1" name="bar" value="60" />
</div>
<br>
<button>Click Me</button>

Chrome Extension Script not Working

I am extremely new to creating extensions for chrome, and right now I'm just trying to mess around and create a simple canvas that you can open up and draw on.
When I load popup.html as a normal webpage everything seems to work just fine, but when I open the extension in chrome there is no functionality.
Manifest:
{
"manifest_version": 2,
"name": "Sketchpad",
"description": " ",
"version": "0.1",
"browser_action": {
"default_icon": "icon.png",
"default_popup": "popup.html"
}
}
HTML:
<!doctype html>
<html>
<head>
<title>Drawing Pad</title>
<style>
body {
font-family: "Segoe UI", "Lucida Grande", Tahoma, sans-serif;
font-size: 100%;
}
.color {display: inline-block;}
#can {
cursor: url(pencil.png), auto;
}
</style>
<script src="canvas.js"></script>
</head>
<body onload="init()">
<canvas id="can" width="400" height="400" style="border:2px solid;"></canvas><br>
<div style="display: inline-block;">Choose Color
<div class="color" style="width: 10px; height: 10px; background: green;" id="green" onclick="color(this)"></div>
<div class="color" style="width: 10px; height: 10px; background: blue;" id="blue" onclick="color(this)"></div>
<div class="color" style="width: 10px; height: 10px; background: red;" id="red" onclick="color(this)"></div>
<div class="color" style="width: 10px; height: 10px; background: yellow;" id="yellow" onclick="color(this)"></div>
<div class="color" style="width: 10px; height: 10px; background: orange;" id="orange" onclick="color(this)"></div>
<div class="color" style="width: 10px; height: 10px; background: black;" id="black" onclick="color(this)"></div>
</div>
<div style="display: inline-block;">Eraser
<div style="width:15px;height:15px;background:white;border:2px solid;display: inline-block" id="white" onclick="color(this)"></div>
</div><br>
<input type="button" value="Clear" id="clr" size="23" onclick="erase()">
</body>
</html>
JS:
var canvas, ctx, flag = false,
prevX = 0,
currX = 0,
prevY = 0,
currY = 0,
dot_flag = false;
var x = "black",
y = 2;
function init() {
canvas = document.getElementById('can');
ctx = canvas.getContext("2d");
w = canvas.width;
h = canvas.height;
canvas.addEventListener("mousemove", function (e) {
findxy('move', e)
}, false);
canvas.addEventListener("mousedown", function (e) {
findxy('down', e)
}, false);
canvas.addEventListener("mouseup", function (e) {
findxy('up', e)
}, false);
canvas.addEventListener("mouseout", function (e) {
findxy('out', e)
}, false);
}
function color(obj) {
switch (obj.id) {
case "green":
x = "green";
break;
case "blue":
x = "blue";
break;
case "red":
x = "red";
break;
case "yellow":
x = "yellow";
break;
case "orange":
x = "orange";
break;
case "black":
x = "black";
break;
case "white":
x = "white";
break;
}
if (x == "white") y = 14;
else y = 2;
}
function draw() {
ctx.beginPath();
ctx.moveTo(prevX, prevY);
ctx.lineTo(currX, currY);
ctx.strokeStyle = x;
ctx.lineWidth = y;
ctx.stroke();
ctx.closePath();
}
function erase() {
ctx.clearRect(0, 0, w, h);
}
function findxy(res, e) {
if (res == 'down') {
prevX = currX;
prevY = currY;
currX = e.clientX - canvas.offsetLeft;
currY = e.clientY - canvas.offsetTop;
flag = true;
dot_flag = true;
if (dot_flag) {
ctx.beginPath();
ctx.fillStyle = x;
ctx.fillRect(currX, currY, 2, 2);
ctx.closePath();
dot_flag = false;
}
}
if (res == 'up' || res == "out") {
flag = false;
}
if (res == 'move') {
if (flag) {
prevX = currX;
prevY = currY;
currX = e.clientX - canvas.offsetLeft;
currY = e.clientY - canvas.offsetTop;
draw();
}
}
}
After doing some research I have a feeling that something is wrong with the way I have my js code formatted, but I cannot pinpoint what that is. Sorry for the long post and thanks, any help is appreciated.

You can't put javascript code in html file in goolge-chrome-extension.
replace
html
<body onload="init()">
with:
js
document.body.addEventListener('load', function () {...})
For more information, see contentSecurityPolicy.

Also since inline JS is not allowed, onclick like <input type="button" value="Clear" id="clr" size="23" onclick="erase()"> should be
<input type="button" value="Clear" id="clr" size="23"> and use addEventListener to bind the event in your js file.
document.addEventListener('DOMContentLoaded', function() {
var clear = document.getElementById('clr');
clear.addEventListener('click', function() {
erase();
});
});

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