HTML Canvas & Javascript - Hover and Click Events - javascript

Below is a script which defines two functions that draw 4 rectangular buttons and 1 circular button respectively. I am trying to implement specific Hover and Click functionality into the buttons (as described in the script alerts) but I am at a bit of a loss as to how to do this. I tried calling the makeInteractiveButton() functions on each click but this caused a lot of odd overlap and lag. I want the script to do the following:
If the circular button is hovered, I would like it's fillColour to change and if it is clicked I would like it to change again to the colours described in the code (#FFC77E for hover, #FFDDB0 for clicked). This should only happen for the duration of the hover or click.
HTML:
<html lang="en">
<body>
<canvas id="game" width = "750" height = "500"></canvas>
<script type='text/javascript' src='stack.js'></script>
</body>
</html>
JavaScript:
var c=document.getElementById('game'),
canvasX=c.offsetLeft,
canvasY=c.offsetTop,
ctx=c.getContext('2d')
elements = [];
c.style.background = 'grey';
function makeInteractiveButton(x, strokeColor, fillColor) {
ctx.strokeStyle=strokeColor;
ctx.fillStyle=fillColor;
ctx.beginPath();
ctx.lineWidth=6;
ctx.arc(x, 475, 20, 0, 2*Math.PI);
ctx.closePath();
ctx.stroke();
ctx.fill();
elements.push({
arcX: x,
arcY: 475,
arcRadius: 20
});
}
b1 = makeInteractiveButton(235, '#FFFCF8', '#FFB85D');
c.addEventListener('mousemove', function(event) {
x=event.pageX-canvasX; // cursor location
y=event.pageY-canvasY;
elements.forEach(function(element) {
if (x > element.left && x < element.left + element.width &&
y > element.top && y < element.top + element.height) { // if cursor in rect
alert('Rectangle should undergo 5 degree rotation and 105% scale');
}
else if (Math.pow(x-element.arcX, 2) + Math.pow(y-element.arcY, 2) <
Math.pow(element.arcRadius, 2)) { // if cursor in circle
alert('Set b1 fillColour to #FFC77E.');
}
});
}, false);
c.addEventListener('click', function(event) {
x=event.pageX-canvasX; // cursor location
y=event.pageY-canvasY;
elements.forEach(function(element) {
if (x > element.left && x < element.left + element.width &&
y > element.top && y < element.top + element.height) { // if rect clicked
alert('Move all cards to centre simultaneously.');
}
else if (Math.pow(x-element.arcX, 2) + Math.pow(y-element.arcY, 2) <
Math.pow(element.arcRadius, 2)) { // if circle clicked
alert('Set b1 fillColour to #FFDDB0.');
}
});
}, false);

One way is keep all element data and write a hitTest(x,y) function but when you have a lot of complex shapes its better to use a secondary canvas to render element with their ID instead of their color in it and the color of x,y in second canvas is ID of hitted element, I should mention that the second canvas is'nt visible and its just a gelper for get the hitted element.
Github Sample:
https://siamandmaroufi.github.io/CanvasElement/
Simple implementation of hitTest for Rectangles :
var Rectangle = function(id,x,y,width,height,color){
this.id = id;
this.x=x;
this.y=y;
this.width = width;
this.height = height;
this.color = color || '#7cf';
this.selected = false;
}
Rectangle.prototype.draw = function(ctx){
ctx.fillStyle = this.color;
ctx.fillRect(this.x,this.y,this.width,this.height);
if(this.selected){
ctx.strokeStyle='red';
ctx.setLineDash([5,5]);
ctx.lineWidth = 5;
ctx.strokeRect(this.x,this.y,this.width,this.height);
}
}
Rectangle.prototype.hitTest=function(x,y){
return (x >= this.x) && (x <= (this.width+this.x)) &&
(y >= this.y) && (y <= (this.height+this.y));
}
var Paint = function(el) {
this.element = el;
this.shapes = [];
}
Paint.prototype.addShape = function(shape){
this.shapes.push(shape);
}
Paint.prototype.render = function(){
//clear the canvas
this.element.width = this.element.width;
var ctx = this.element.getContext('2d');
for(var i=0;i<this.shapes.length;i++){
this.shapes[i].draw(ctx);
}
}
Paint.prototype.setSelected = function(shape){
for(var i=0;i<this.shapes.length;i++){
this.shapes[i].selected = this.shapes[i]==shape;
}
this.render();
}
Paint.prototype.select = function(x,y){
for(var i=this.shapes.length-1;i>=0;i--){
if(this.shapes[i].hitTest(x,y)){
return this.shapes[i];
}
}
return null;
}
var el = document.getElementById('panel');
var paint = new Paint(el);
var rectA = new Rectangle('A',10,10,150,90,'yellow');
var rectB = new Rectangle('B',150,90,140,100,'green');
var rectC = new Rectangle('C',70,85,200,70,'rgba(0,0,0,.5)');
paint.addShape(rectA);
paint.addShape(rectB);
paint.addShape(rectC);
paint.render();
function panel_mouseUp(evt){
var p = document.getElementById('panel');
var x = evt.x - p.offsetLeft;
var y = evt.y - p.offsetTop;
var shape = paint.select(x,y);
if(shape){
alert(shape.id);
}
//console.log('selected shape :',shape);
}
function panel_mouseMove(evt){
var p = document.getElementById('panel');
var x = evt.x - p.offsetLeft;
var y = evt.y - p.offsetTop;
var shape = paint.select(x,y);
paint.setSelected(shape);
}
el.addEventListener('mouseup',panel_mouseUp);
el.addEventListener('mousemove',panel_mouseMove);
body {background:#e6e6e6;}
#panel {
border:solid thin #ccc;
background:#fff;
margin:0 auto;
display:block;
}
<canvas id="panel" width="400px" height="200px" >
</canvas>
just click or move over the shapes

Related

How to use a table as a drawing grid

I am trying to create a table with ~10,000 cells and turn this into a canvas on which the user can draw with mouse movements.
I would like to be able to draw on the canvas by highlighting the background of cells the mouse moves over when holding certain keys (blue = ctrl, red = shift, etc).
I have generated my HTML code but I am having trouble with the table. It seems that it is trying to select table cells instead of coloring in the cells.
Here is a screenshot of what I am talking about:
HTML:
<html>
<head>
<meta charset="utf-8">
<title>Drawing Program</title>
<h1>Drawing Demonstration</h1>
<link rel = "stylesheet" type = "text/css" href = "style.css">
<script src = "draw.js"></script>
</head>
<body>
<table id = "canvas">
<caption>Hold Ctrl (or Control) to draw in blue.
Hold Shift to draw in red.</caption>
<tbody id = "tablebody"></tbody>
</table>
</body>
</html>
CSS:
table{
width: 400px;
height: 400px;
border-collapse: collapse;
}
td {
width: 4px;
height: 4px;
border-collapse: collapse;
}
JavaScript:
function createCanvas()
{
var side = 100;
var tbody = document.getElementById( "tablebody" );
for( var i = 0; i < side; i++)
{
var row = document.createElement( "tr" );
for( var j = 0; j < side; j++)
{
var cell = document.createElement( "td" );
row.appendChild( cell );
}
tbody.appendChild( row );
}
document.getElementById( "canvas" ).addEventListener( "mousemove", processMouseMove, false );
}
function processMouseMove( e )
{
if( e.target.tagName.toLowerCase() == "td" )
{
if( e.ctrlKey )
{
e.target.setAttribute( "class", "blue" );
}
if ( e.shiftKey )
{
e.target.setAttribute( "class", "red" );
}
}
}
window.addEventListener( "load", createCanvas, false );
Instead of making ten thousand table cells, I recommend that you make a canvas element and paint it with pixels that are the size of table cells. You can convert the mouse coordinates into pixel positions with modulo arithmetic.
For example, if the mouse is at (x, y) and each pixel has size 4, the mouse is over the pixel such that:
row = x - x % 4
column = y - y % 4
The following snippet demonstrates this approach. When you run the snippet, you'll have to click inside the frame containing the canvas in order to give mouse focus to the frame.
var Paint = {
pixel: { size: 4 },
grid: { numRows: 100, numCols: 100 }
};
window.onload = function () {
var canvas = document.getElementById('paintCanvas'),
context = canvas.getContext('2d'),
offset = getOffset(canvas, document.body),
pixelSize = Paint.pixel.size,
numRows = Paint.grid.numRows,
numCols = Paint.grid.numCols,
painting = false;
canvas.width = numCols * pixelSize;
canvas.height = numRows * pixelSize;
window.onkeydown = function (event) {
var code = event.which;
if (code == 17 || code == 16) {
painting = true;
context.fillStyle = (code == 17 ? '#1b6bb5' : '#b53a31');
}
};
window.onkeyup = function (event) {
var code = event.which;
if (code == 17 || code == 16) {
painting = false;
}
};
canvas.onmousemove = function (event) {
if (!painting) {
return;
}
event = event || window.event;
var mouse = getMousePosition(event),
x = mouse.x - offset.left,
y = mouse.y - offset.top;
x -= x % pixelSize;
y -= y % pixelSize;
context.fillRect(x, y, pixelSize, pixelSize);
};
};
function getOffset(element, ancestor) {
var left = 0,
top = 0;
while (element != ancestor) {
left += element.offsetLeft;
top += element.offsetTop;
element = element.parentNode;
}
return { left: left, top: top };
}
function getMousePosition(event) {
if (event.pageX !== undefined) {
return { x: event.pageX, y: event.pageY };
}
return {
x: event.clientX + document.body.scrollLeft +
document.documentElement.scrollLeft,
y: event.clientY + document.body.scrollTop +
document.documentElement.scrollTop
};
}
body {
font-family: sans-serif;
}
canvas {
border: 2px solid #ccc;
}
<p> <b>Click here to start.</b> Hold Ctrl to draw in blue, Shift to draw in red. </p>
<canvas id="paintCanvas"></canvas>
I would add a blank div position absolute in front of the table and read the td height and width to calculate the xy position in the table from the mouse move. and then do the table magic.

Draw clickable grid of 1 million squares

I need to find a way to draw a 1000x1000 squares grid, each square is clickable and they must be independently color changeable. Like mines game. I can use HTML (pure or using Canvas or SVG), CSS and JavaScript for this.
I know how to create one grid with these characteristics with JavaScript and CSS, it does well with 10x10 squares, with 100x100 the squares will turn into tall rectangles and 1000x1000 it loads, but the "squares" are soo much compressed that borders meet each other and renders a full gray page.
I tried using HTML and JavaScript to draw SVG squares, the squares' size problem solves, but I don't know how to make they change color when clicked and when I set to load 1000x1000 squares it will freeze the browse and eventually crash the tab.
Is this feasible in any way?
EDIT
Sorry if I wasn't clear, but yes, I need scroll bars in that. They are no problem for me.
You can see the two trials I described here:
JavaScript and CSS
var lastClicked;
var grid = clickableGrid(100,100,function(el,row,col,i){
console.log("You clicked on element:",el);
console.log("You clicked on row:",row);
console.log("You clicked on col:",col);
console.log("You clicked on item #:",i);
el.className='clicked';
if (lastClicked) lastClicked.className='';
lastClicked = el;
});
document.body.appendChild(grid);
function clickableGrid( rows, cols, callback ){
var i=0;
var grid = document.createElement('table');
grid.className = 'grid';
for (var r=0;r<rows;++r){
var tr = grid.appendChild(document.createElement('tr'));
for (var c=0;c<cols;++c){
var cell = tr.appendChild(document.createElement('td'));
++i;
cell.addEventListener('click',(function(el,r,c,i){
return function(){
callback(el,r,c,i);
}
})(cell,r,c,i),false);
}
}
return grid;
}
.grid { margin:1em auto; border-collapse:collapse }
.grid td {
cursor:pointer;
width:30px; height:30px;
border:1px solid #ccc;
}
.grid td.clicked {
background-color:gray;
}
JavaScript and HTML
document.createSvg = function(tagName) {
var svgNS = "http://www.w3.org/2000/svg";
return this.createElementNS(svgNS, tagName);
};
var numberPerSide = 20;
var size = 10;
var pixelsPerSide = 400;
var grid = function(numberPerSide, size, pixelsPerSide, colors) {
var svg = document.createSvg("svg");
svg.setAttribute("width", pixelsPerSide);
svg.setAttribute("height", pixelsPerSide);
svg.setAttribute("viewBox", [0, 0, numberPerSide * size, numberPerSide * size].join(" "));
for(var i = 0; i < numberPerSide; i++) {
for(var j = 0; j < numberPerSide; j++) {
var color1 = colors[(i+j) % colors.length];
var color2 = colors[(i+j+1) % colors.length];
var g = document.createSvg("g");
g.setAttribute("transform", ["translate(", i*size, ",", j*size, ")"].join(""));
var number = numberPerSide * i + j;
var box = document.createSvg("rect");
box.setAttribute("width", size);
box.setAttribute("height", size);
box.setAttribute("fill", color1);
box.setAttribute("id", "b" + number);
g.appendChild(box);
svg.appendChild(g);
}
}
svg.addEventListener(
"click",
function(e){
var id = e.target.id;
if(id)
alert(id.substring(1));
},
false);
return svg;
};
var container = document.getElementById("container");
container.appendChild(grid(100, 10, 2000, ["gray", "white"]));
<div id="container">
</div>
I will be trying implementing the given answers and ASAP I'll accept or update this question. Thanks.
SOLUTION
Just to record, I managed to do it using canvas to draw the grid and the clicked squares and added an event listener to know where the user clicks.
Here is the code in JavaScript and HTML:
function getSquare(canvas, evt) {
var rect = canvas.getBoundingClientRect();
return {
x: 1 + (evt.clientX - rect.left) - (evt.clientX - rect.left)%10,
y: 1 + (evt.clientY - rect.top) - (evt.clientY - rect.top)%10
};
}
function drawGrid(context) {
for (var x = 0.5; x < 10001; x += 10) {
context.moveTo(x, 0);
context.lineTo(x, 10000);
}
for (var y = 0.5; y < 10001; y += 10) {
context.moveTo(0, y);
context.lineTo(10000, y);
}
context.strokeStyle = "#ddd";
context.stroke();
}
function fillSquare(context, x, y){
context.fillStyle = "gray"
context.fillRect(x,y,9,9);
}
var canvas = document.getElementById('myCanvas');
var context = canvas.getContext('2d');
drawGrid(context);
canvas.addEventListener('click', function(evt) {
var mousePos = getSquare(canvas, evt);
fillSquare(context, mousePos.x, mousePos.y)
}, false);
<body>
<canvas id="myCanvas" width="10000" height="10000"></canvas>
</body>
Generating such a large grid with HTML is bound to be problematic.
Drawing the grid on a Canvas and using a mouse-picker technique to determine which cell was clicked would be much more efficient.
This would require 1 onclick and/or hover event instead of 1,000,000.
It also requires much less HTML code.
I wouldn't initialize all the squares right off, but instead as they are clicked -
(function() {
var divMain = document.getElementById('main'),
divMainPosition = divMain.getBoundingClientRect(),
squareSize = 4,
square = function(coord) {
var x = coord.clientX - divMainPosition.x + document.body.scrollLeft +
document.documentElement.scrollLeft,
y = coord.clientY - divMainPosition.y + document.body.scrollTop +
document.documentElement.scrollTop;
return {
x:Math.floor(x / squareSize),
y:Math.floor(y / squareSize)
}
}
divMain.addEventListener('click', function(evt) {
var sqr = document.createElement('div'),
coord = square(evt);
sqr.className = 'clickedSquare';
sqr.style.width = squareSize + 'px';
sqr.style.height = squareSize + 'px';
sqr.style.left = (coord.x * squareSize) + 'px';
sqr.style.top = (coord.y * squareSize) + 'px';
sqr.addEventListener('click', function(evt) {
console.log(this);
this.parentNode.removeChild(this);
evt.stopPropagation();
});
this.appendChild(sqr);
});
}());
#main {
width:4000px;
height:4000px;
background-color:#eeeeee;
position:relative;
}
.clickedSquare {
background-color:#dd8888;
position:absolute;
}
<div id="main">
</div>
Uses CSS positioning to determine which square was clicked on,
doesn't initialize a square until it's needed.
Granted I imagine this would start to have a negative impact to use r experience, but that would ultimately depend on their browser and machine.
Use the same format you noramlly use, but add this:
sqauareElement.height = 10 //height to use
squareElement.width = 10 //width to use
This will add quite a large scroll due to the size, but it's the only logical explanation I can come up with.
The canvas approach is fine, but event delegation makes it possible to do this with a table or <div> elements with a single listener:
const tbodyEl = document.querySelector("table tbody");
tbodyEl.addEventListener("click", event => {
const cell = event.target.closest("td");
if (!cell || !tbodyEl.contains(cell)) {
return;
}
const row = +cell.getAttribute("data-row");
const col = +cell.getAttribute("data-col");
console.log(row, col);
});
const rows = 100;
const cols = 100;
for (let i = 0; i < rows; i++) {
const rowEl = document.createElement("tr");
tbodyEl.appendChild(rowEl);
for (let j = 0; j < cols; j++) {
const cellEl = document.createElement("td");
rowEl.appendChild(cellEl);
cellEl.classList.add("cell");
cellEl.dataset.row = i;
cellEl.dataset.col = j;
}
}
.cell {
height: 4px;
width: 4px;
cursor: pointer;
border: 1px solid black;
}
table {
border-collapse: collapse;
}
<table><tbody></tbody></table>

How to add tooltip on draggable objects within Canvas?

In my code SVG is parse and drawn on Canvas and also orange1.png and green1.png images are plotted on SVg file. In this I am able to zoom and Pan canvas and also able to drag images which are plotted on it through JSON.
Now I want to add tooltip on the images (orange1.png and green1.png) When I click on those images or mouseover on those images.
showTooltip function is for showing the tooltip on those images(orange1.png , green1.png).
clearTooltip function is for clearing the tooltip.
Where and how should I add showTooltip and clearTooltip function in my updated code?
And which option will be better mouse click or mosehover for showing tooltip?
I tried some possibilities but I am missing something.
function showTooltip(x, y, index) {
var editedValue = [];
if (tooltip === null) {
tooltip = document.createElement('div');
tooltip.className = 'tooltip';
tooltip.style.left = (x) + 'px';
tooltip.style.top = (y) + 'px';
tooltip.innerHTML = "<input type='text' id='generic_txt' value='"+dataJSON[index].tooltiptxt[0]+"' /> <input type='submit' id='generic_edit' value='Edit'>"
document.getElementsByTagName('body')[0].appendChild(tooltip);
}
document.getElementById('generic_txt').setAttribute('disabled', 'disabled');
$("#generic_edit").click(function(){
if(document.getElementById('generic_edit').value == "Edit"){
document.getElementById('generic_txt').removeAttribute('disabled');
document.getElementById('generic_txt').focus();
document.getElementById('generic_edit').value = "Change";
} else {
document.getElementById('generic_txt').setAttribute('disabled', 'disabled');
document.getElementById('generic_edit').value = "Edit";
editedValue = $('#generic_txt').val();
dataJSON[index].tooltiptxt[0] = editedValue; // important line
}
return false;
});
}
function clearTooltip(doFade) {
if (tooltip !== null) {
var fade = 1;
function fadeOut() {
tooltip.style.opacity = fade;
fade -= 0.1;
if (fade > 0) {
setTimeout(fadeOut, 16);
} else {
remove();
}
}
function remove() {
document.getElementsByTagName('body')[0].removeChild(tooltip);
tooltip = null;
}
if (doFade === true) {
fadeOut();
//$('.first_cancel').click(fadeOut());
} else {
remove();
}
}
}
Following is my updated source code.
HTML Code :
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
<head>
<script src="http://code.jquery.com/jquery-1.10.1.min.js"></script>
<style>
canvas {
border:1px solid #000
}
.tooltip{
*position:fixed;
position:absolute;
*background:#ff7;
background:green;
border:1px solid #000;
padding:7px;
font-family:sans-serif;
font-size:12px;
}
.tooltip2 {
*position:fixed;
position:absolute;
background:pink;
border:1px solid #000;
padding:7px;
font-family:sans-serif;
font-size:12px;
}
</style>
</head>
<body>
<script src="http://canvg.googlecode.com/svn/trunk/rgbcolor.js"></script>
<script src="http://canvg.googlecode.com/svn/trunk/StackBlur.js"></script>
<script src="http://canvg.googlecode.com/svn/trunk/canvg.js"></script>
<canvas id="myCanvas" width="800" height="700" style="border: 1px solid;margin-top: 10px;"></canvas>
<div id="buttonWrapper">
<input type="button" id="plus" value="+">
<input type="button" id="minus" value="-">
<input type="button" id="original_size" value="100%">
</div>
<script src="/static/js/markers.js"></script>
<script src="/static/js/draw.js"></script>
</body>
</html>
draw.js:
var dataJSON = data || [];
var dataJSON2 = data2 || [];
window.onload = function(){
//$(function(){
var canvas=document.getElementById("myCanvas");
var ctx=canvas.getContext("2d");
var canvasOffset=$("#myCanvas").offset();
var offsetX=canvasOffset.left;
var offsetY=canvasOffset.top;
var lastX=0;
var lastY=0;
var panX=0;
var panY=0;
var dragging=[];
var dragging2=[];
var isDown=false;
function loadImages(sources, callback){
var images = {};
var loadImages = 0;
var numImages = 0;
//get num of sources
for(var i in sources){
numImages++;
}
for(var i in sources){
images[i] = new Image();
images[i].onload = function(){
if(++loadImages >= numImages){
callback(images);
}
};
images[i].src = sources[i];
}
}
var sources = {orange : '/static/images/orange1.png', green : '/static/images/green1.png'};
// load the tiger image
var svgfiles = ["/static/images/awesome_tiger.svg"];
/*var tiger=new Image();
tiger.onload=function(){
draw();
}
tiger.src="tiger.png";*/
function draw(scaleValue){
ctx.clearRect(0,0,canvas.width,canvas.height);
ctx.save();
ctx.drawSvg(svgfiles[0],panX,panY,400*scaleValue, 400*scaleValue);
//ctx.drawImage(tiger,panX,panY,tiger.width,tiger.height);
//ctx.scale(scaleValue, scaleValue);
loadImages(sources, function(images){
ctx.scale(scaleValue, scaleValue);
for(var i = 0, pos; pos = dataJSON[i]; i++) {
ctx.drawImage(images.orange, parseInt(parseInt(pos.x) + parseInt(panX / scaleValue)), parseInt(parseInt(pos.y) + parseInt(panY / scaleValue)), 20/scaleValue, 20/scaleValue);
}
for(var i = 0, pos; pos = dataJSON2[i]; i++) {
ctx.drawImage(images.green, parseInt(parseInt(pos.x) + parseInt(panX / scaleValue)), parseInt(parseInt(pos.y) + parseInt(panY / scaleValue)), 20/scaleValue, 20/scaleValue);
}
ctx.restore();
});
};
var scaleValue = 1;
var scaleMultiplier = 0.8;
draw(scaleValue);
var startDragOffset = {};
var mouseDown = false;
// add button event listeners
document.getElementById("plus").addEventListener("click", function(){
scaleValue /= scaleMultiplier;
//checkboxZoomPan();
draw(scaleValue);
}, false);
document.getElementById("minus").addEventListener("click", function(){
scaleValue *= scaleMultiplier;
//checkboxZoomPan();
draw(scaleValue);
}, false);
document.getElementById("original_size").addEventListener("click", function(){
scaleValue = 1;
//checkboxZoomPan();
draw(scaleValue);
}, false);
// create an array of any "hit" colored-images
function imagesHitTests(x,y){
// adjust for panning
x-=panX;
y-=panY;
// create var to hold any hits
var hits=[];
// hit-test each image
// add hits to hits[]
loadImages(sources, function(images){
for(var i = 0, pos; pos = dataJSON[i]; i++) {
if(x >= parseInt(pos.x * scaleValue) && x <= parseInt((pos.x * scaleValue) + 20) && y >= parseInt(pos.y * scaleValue) && y <= parseInt((pos.y * scaleValue) + 20)){
hits.push(i);
}
}
});
return(hits);
}
function imagesHitTests2(x,y){
// adjust for panning
//x-=panX;
//x = parseInt(x) - parseInt(panX);
// y-=panY;
x-=panX;
y-=panY;
// create var to hold any hits
var hits2=[];
// hit-test each image
// add hits to hits[]
loadImages(sources, function(images){
for(var i = 0, pos; pos = dataJSON2[i]; i++) {
//if(x > pos.x && x < parseInt(parseInt(pos.x) + parseInt(20)) && y > pos.y && y < parseInt(parseInt(pos.y) + parseInt(20))){
if(x >= parseInt(pos.x * scaleValue) && x <= parseInt((pos.x * scaleValue) + 20) && y >= parseInt(pos.y * scaleValue) && y <= parseInt((pos.y * scaleValue) + 20)){
hits2.push(i);
}
}
});
return(hits2);
}
function handleMouseDown(e){
// get mouse coordinates
mouseX=parseInt(e.clientX-offsetX);
mouseY=parseInt(e.clientY-offsetY);
// set the starting drag position
lastX=mouseX;
lastY=mouseY;
// test if we're over any of the images
dragging=imagesHitTests(mouseX,mouseY);
dragging2=imagesHitTests2(mouseX,mouseY);
// set the dragging flag
isDown=true;
}
function handleMouseUp(e){
// clear the dragging flag
isDown=false;
}
function handleMouseMove(e){
// if we're not dragging, exit
if(!isDown){
return;
}
//get mouse coordinates
mouseX=parseInt(e.clientX-offsetX);
mouseY=parseInt(e.clientY-offsetY);
// calc how much the mouse has moved since we were last here
var dx=mouseX-lastX;
var dy=mouseY-lastY;
// set the lastXY for next time we're here
lastX=mouseX;
lastY=mouseY;
// handle drags/pans
if(dragging.length>0){
// we're dragging images
// move all affected images by how much the mouse has moved
for(var i = 0, pos; pos = dataJSON[dragging[i]]; i++) {
pos.x = parseInt(pos.x) + parseInt(dx);
pos.y = parseInt(pos.y) + parseInt(dy);
}
}
else if(dragging2.length>0){
for(var i = 0, pos1; pos1 = dataJSON2[dragging2[i]]; i++) {
pos1.x = parseInt(pos1.x) + parseInt(dx);
pos1.y = parseInt(pos1.y) + parseInt(dy);
}
}
else{
// we're panning the tiger
// set the panXY by how much the mouse has moved
panX+=dx;
panY+=dy;
}
draw(scaleValue);
}
// use jQuery to handle mouse events
$("#myCanvas").mousedown(function(e){handleMouseDown(e);});
$("#myCanvas").mousemove(function(e){handleMouseMove(e);});
$("#myCanvas").mouseup(function(e){handleMouseUp(e);});
// }); // end $(function(){});
}
markers.js:
data = [
{ "id" :["first"],
"x": ["195"],
"y": ["150"],
"tooltiptxt": ["Region 1"]
},
{
"id" :["second"],
"x": ["255"],
"y": ["180"],
"tooltiptxt": ["Region 2"]
},
{
"id" :["third"],
"x": ["200"],
"y": ["240"],
"tooltiptxt": ["Region 3"]
}
];
data2 = [
{ "id" :["first2"],
"x": ["225"],
"y": ["150"],
"tooltiptxt": ["Region 21"]
},
{
"id" :["second2"],
"x": ["275"],
"y": ["180"],
"tooltiptxt": ["Region 22"]
},
{
"id" :["third3"],
"x": ["300"],
"y": ["240"],
"tooltiptxt": ["Region 23"]
}
];
I think you can try out this :
<!DOCTYPE html>
<html>
<head>
<title>Canvas Links Example</title>
<script>
function OnLoad(){
var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext("2d");
ctx.translate(0.5, 0.5);
ctx.strokeStyle = "#5F7FA2";
ctx.strokeRect(50, 50, 25, 25);
var img = new Image();
img.src = "http://www.cs.washington.edu/education/courses/csep576/05wi/projects/project4/web/artifact/liebling/average_face.gif";
var img1 = new Image();
img1.src = "E:\Very IMP Projects\WinService\SourceCode\MVC\BpmPresentation\Images\loading.gif";
img.onload = function(){
ctx.drawImage(img, 50, 50);
canvas.addEventListener("mousemove", on_mousemove, false);
canvas.addEventListener("click", on_click, false);
Links.push(50 + ";" + 50 + ";" + 25 + ";" + 25 + ";" + "http://plus.google.com/");
}
var Links = new Array();
var hoverLink = "";
var canvas1 = document.getElementById("myCanvas1");
var ctx1 = canvas1.getContext("2d");
function on_mousemove (ev) {
var x, y;
if (ev.layerX || ev.layerX == 0) { // For Firefox
x = ev.layerX;
y = ev.layerY;
}
for (var i = Links.length - 1; i >= 0; i--) {
var params = new Array();
params = Links[i].split(";");
var linkX = parseInt(params[0]),
linkY = parseInt(params[1]),
linkWidth = parseInt(params[2]),
linkHeight = parseInt(params[3]),
linkHref = params[4];
if (x >= linkX && x <= (linkX + linkWidth) && y >= linkY && y <= (linkY + linkHeight)){
document.body.style.cursor = "pointer";
hoverLink = linkHref;
ctx1.translate(0.5, 0.5);
ctx1.strokeStyle = "#5F7FA2";
canvas1.style.left = x + "px";
canvas1.style.top = (y+40) + "px";
ctx1.clearRect(0, 0, canvas1.width, canvas1.height);
var img1 = new Image();
img1.src = "E:\Very IMP Projects\WinService\SourceCode\MVC\BpmPresentation\Images\loading.gif";
img1.onload = function () {
ctx1.drawImage(img1, 50, 50);
}
break;
}
else {
document.body.style.cursor = "";
hoverLink = "";
canvas1.style.left = "-200px";
}
};
}
function on_click(e) {
if (hoverLink) {
window.open(hoverLink);
//window.location = hoverLink;
}
}
}
</script>
</head>
<body onload="OnLoad();">
<canvas id="myCanvas" width="450" height="250" style="border:1px solid #eee;">
Canvas is not supported in your browser ! :(
</canvas>
<canvas id="myCanvas1" width="50" height="50" style="background-color:white;border:1px solid blue;position:absolute;left:-200px;top:100px;">
</canvas>
</body>
</html>

Draw on click or touch event

im learnig javascript and try to develop a page to draw on. Change colors and linewidth are already in place. Now it is drawing, but just when I move the mouse. I'd like to add also on click on just on move. So I'm able to draw also points. I have put the drawCircle function in the function stopDraw, but this is not working as it should. Any ideas?
Second problem is that, I'd like to draw a circle without stroke. But as soon as I change the lineWidth, also my circle gets a stroke around. Please help...
// Setup event handlers
cb_canvas = document.getElementById("cbook");
cb_lastPoints = Array();
if (cb_canvas.getContext) {
cb_ctx = cb_canvas.getContext('2d');
cb_ctx.lineWidth = 14;
cb_ctx.strokeStyle = "#0052f8";
cb_ctx.lineJoin="round";
cb_ctx.lineCap="round"
cb_ctx.beginPath();
cb_canvas.onmousedown = startDraw;
cb_canvas.onmouseup = stopDraw;
cb_canvas.ontouchstart = startDraw;
cb_canvas.ontouchend = stopDraw;
cb_canvas.ontouchmove = drawMouse;
}
function startDraw(e) {
if (e.touches) {
// Touch event
for (var i = 1; i <= e.touches.length; i++) {
cb_lastPoints[i] = getCoords(e.touches[i - 1]); // Get info for finger #1
}
}
else {
// Mouse event
cb_lastPoints[0] = getCoords(e);
cb_canvas.onmousemove = drawMouse;
}
return false;
}
// Called whenever cursor position changes after drawing has started
function stopDraw(e) {
drawCircle(e);
e.preventDefault();
cb_canvas.onmousemove = null;
}
//Draw circle
function drawCircle(e) {
var canvasOffset = canvas.offset();
var canvasX = Math.floor(e.pageX-canvasOffset.left);
var canvasY = Math.floor(e.pageY-canvasOffset.top);
//var canvasPos = getCoords(e);
cb_ctx.beginPath();
cb_ctx.arc(canvasX, canvasY, cb_ctx.lineWidth/2, 0, Math.PI*2, true);
cb_ctx.fillStyle = cb_ctx.strokeStyle;
cb_ctx.fill();
}
function drawMouse(e) {
cb_ctx.beginPath();
if (e.touches) {
// Touch Enabled
for (var i = 1; i <= e.touches.length; i++) {
var p = getCoords(e.touches[i - 1]); // Get info for finger i
cb_lastPoints[i] = drawLine(cb_lastPoints[i].x, cb_lastPoints[i].y, p.x, p.y);
}
}
else {
// Not touch enabled
var p = getCoords(e);
cb_lastPoints[0] = drawLine(cb_lastPoints[0].x, cb_lastPoints[0].y, p.x, p.y);
}
cb_ctx.stroke();
cb_ctx.closePath();
//cb_ctx.beginPath();
return false;
}
// Draw a line on the canvas from (s)tart to (e)nd
function drawLine(sX, sY, eX, eY) {
cb_ctx.moveTo(sX, sY);
cb_ctx.lineTo(eX, eY);
return { x: eX, y: eY };
}
// Get the coordinates for a mouse or touch event
function getCoords(e) {
if (e.offsetX) {
return { x: e.offsetX, y: e.offsetY };
}
else if (e.layerX) {
return { x: e.layerX, y: e.layerY };
}
else {
return { x: e.pageX - cb_canvas.offsetLeft, y: e.pageY - cb_canvas.offsetTop };
}
}
Your drawCircle function is wrapped in the canvas's onclick event. It should be
function drawCircle(e) {
var canvasOffset = canvas.offset();
var canvasX = Math.floor(e.pageX-canvasOffset.left);
var canvasY = Math.floor(e.pageY-canvasOffset.top);
cb_ctx.beginPath();
cb_ctx.lineWidth = 0;
cb_ctx.arc(canvasX,canvasY,cb_ctx.lineWidth/2,0,Math.PI*2,true);
cb_ctx.fillStyle = cb_ctx.strokeStyle;
cb_ctx.fill();
}
So you'll have to pass the event object from stop draw as well
function stopDraw(e) {
drawCircle(e); //notice the change here
e.preventDefault();
cb_canvas.onmousemove = null;
}
Note that you're also setting you circle's radius to 0 which might be another reason why it's not showing up.
cb_ctx.lineWidth = 0;
cb_ctx.arc(canvasX,canvasY,cb_ctx.lineWidth/2,0,Math.PI*2,true);
0 divided by 2 is always zero. If you don't want to stroke around the circle just don't call stroke(). the drawCircle function isn't causing that, since there's a beginPath() call. I suspect it's because you don't beginPath() before calling stroke() in drawMouse.

Displaying Hidden Div on Canvas position mousemoves

Currently I'm creating a sheet of graph paper with the canvas object in HTML5. I'm able to create the canvas as well as fill in the selected areas with a color by finding the x/y position. Unfortunately I'm having some troubles using the jQuery mousemove method to display a pop-up of the information selected for the square.
Here's my code:
Canvas Creation/Layout:<br>
<script type="text/javascript">
var canvas;
var context;
var color;
var state;
var formElement;
var number = 0;
function showGrid()
{
canvas = document.getElementById('canvas');
context = canvas.getContext('2d');
context.lineWidth=0.5;
context.strokeStyle='#999999';
lineSpacing=10;
var xPos = 0;
var yPos = 0;
var numHorizontalLines = parseInt(canvas.height/lineSpacing);
var numVerticalLines = parseInt(canvas.width/lineSpacing);
state = new Array(numHorizontalLines);
for (var y = 0; y < numHorizontalLines; ++y)
{
state[y] = new Array(numVerticalLines);
}
for(var i=1; i<=numHorizontalLines;i++)
{
yPos=i*lineSpacing;
context.moveTo(0,yPos);
context.lineTo(canvas.width,yPos);
context.stroke;
}
for(var i=1; i<=numVerticalLines; i++)
{
xPos=i*lineSpacing;
context.moveTo(xPos,0);
context.lineTo(xPos,canvas.height);
context.stroke();
}
}
function fill(s, gx, gy)
{
context.fillStyle = s;
context.fillRect(gx * lineSpacing, gy * lineSpacing, lineSpacing, lineSpacing);
if(s != null)
{
}
}
function getPosition(e)
{
var x = new Number();
var y = new Number();
var canvas = document.getElementById("canvas");
if (e.pageX || e.pageY)
{
x = e.pageX;
y = e.pageY;
}
else
{
x = e.clientX + document.body.scrollLeft +
document.documentElement.scrollLeft;
y = e.clientY + document.body.scrollTop +
document.documentElement.scrollTop;
}
x -= canvas.offsetLeft;
y -= canvas.offsetTop;
var gx = Math.floor((x / lineSpacing));
var gy = Math.floor((y / lineSpacing));
state[gy][gx] = true;
fill(color, gx, gy);
addNumber();
}
HTML:
<div class="graphpaper" id="graphpaper" onclick="getPosition(event)" style="width:956px; height:1186px;">
<img src="images/PosterBorder_Top.png" align="right"/>
<img src="images/posterBorder_left.png" align="left" valign="top"/>
<canvas id ="canvas" width = "920" height = "1160" align="left">
</canvas>
</div>
<!-- HIDDEN / POP-UP DIV -->
<div id="pop-up">
<h3>Pop-up div Successfully Displayed</h3>
<p>
This div only appears when the trigger link is hovered over.
Otherwise it is hidden from view.
</p>
</div>
jQuery for Pop-Up display:
$('#canvas').mousemove(function(event){
console.log("Here I am!");
$('div#pop-up').show().appendTo('body');
});
Any suggestions? I'm obviously missing something but from what I've done this should work I believe.

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