I want to draw a box in pdf using canvas and find out the coordinate of drawing box. I have a code here after selection of pdf it convert to a canvas and on that canvas we create box but box not shows. For this use javascript pdf.js and pdf.worker.js
For using this code please use attached javascript files.
<script src="https://cdnjs.cloudflare.com/ajax/libs/pdf.js/1.5.188/pdf.worker.js"></script><script src="https://cdnjs.cloudflare.com/ajax/libs/pdf.js/1.5.188/pdf.js"></script><!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale = 1.0, maximum-scale = 1.0, user-scalable=no">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.4/jquery.min.js"></script>
<script src="pdf.js"></script>
<script src="pdf.worker.js"></script>
<style type="text/css">
#upload-button {
width: 150px;
display: block;
margin: 20px auto;
}
#file-to-upload {
display: none;
}
#pdf-main-container {
width: 400px;
margin: 20px auto;
}
#pdf-loader {
display: none;
text-align: center;
color: #999999;
font-size: 13px;
line-height: 100px;
height: 100px;
}
#pdf-contents {
display: none;
}
#pdf-meta {
overflow: hidden;
margin: 0 0 20px 0;
}
#pdf-buttons {
float: left;
}
#page-count-container {
float: right;
}
#pdf-current-page {
display: inline;
}
#pdf-total-pages {
display: inline;
}
#pdf-canvas {
border: 1px solid rgba(0,0,0,0.2) transparent;
box-sizing: border-box;
background-color:yellow;
}
#page-loader {
height: 100px;
line-height: 100px;
text-align: center;
display: none;
color: #999999;
font-size: 13px;
}
.rectangle {
border: 1px solid #FF0000;
position: absolute;
}
</style>
<script type="text/javascript">
function initDraw(canvas) {
var mouse = {
x: 0,
y: 0,
startX: 0,
startY: 0
};
function setMousePosition(e) {
var ev = e || window.event; //Moz || IE
if (ev.pageX) { //Moz
mouse.x = ev.pageX + window.pageXOffset;
mouse.y = ev.pageY + window.pageYOffset;
} else if (ev.clientX) { //IE
mouse.x = ev.clientX + document.body.scrollLeft;
mouse.y = ev.clientY + document.body.scrollTop;
}
};
var element = null;
canvas.onmousemove = function (e) {
setMousePosition(e);
if (element !== null) {
element.style.width = Math.abs(mouse.x - mouse.startX) + 'px';
element.style.height = Math.abs(mouse.y - mouse.startY) + 'px';
element.style.left = (mouse.x - mouse.startX < 0) ? mouse.x + 'px' : mouse.startX + 'px';
element.style.top = (mouse.y - mouse.startY < 0) ? mouse.y + 'px' : mouse.startY + 'px';
console.log('width : '+ element.style.width);
console.log('height : '+ element.style.height);
console.log('left : '+ element.style.left);
console.log('top : '+ element.style.top);
}
}
canvas.onclick = function (e) {
if (element !== null) {
element = null;
canvas.style.cursor = "default";
console.log("finsihed.");
} else {
console.log("begun.");
mouse.startX = mouse.x;
mouse.startY = mouse.y;
console.log(mouse.x);
console.log(mouse.y);
element = document.createElement('div');
element.className = 'rectangle'
element.style.left = mouse.x + 'px';
element.style.top = mouse.y + 'px';
canvas.appendChild(element)
canvas.style.cursor = "crosshair";
}
}
}
</script>
</head>
<body>
<button id="upload-button">Select PDF</button>
<input type="file" id="file-to-upload" accept="application/pdf" />
<div id="pdf-main-container">
<div id="pdf-loader">Loading document ...</div>
<div id="pdf-contents">
<div id="pdf-meta">
<div id="pdf-buttons">
<button id="pdf-prev">Previous</button>
<button id="pdf-next">Next</button>
</div>
<div id="page-count-container">Page <div id="pdf-current-page"></div> of <div id="pdf-total-pages"></div></div>
</div>
<canvas id="pdf-canvas" width="400"></canvas>
<div id="page-loader">Loading page ...</div>
</div>
<script>
initDraw(document.getElementById('pdf-canvas'));
</script>
</div>
<script>
var __PDF_DOC,
__CURRENT_PAGE,
__TOTAL_PAGES,
__PAGE_RENDERING_IN_PROGRESS = 0,
__CANVAS = $('#pdf-canvas').get(0),
__CANVAS_CTX = __CANVAS.getContext('2d');
function showPDF(pdf_url) {
$("#pdf-loader").show();
PDFJS.getDocument({ url: pdf_url }).then(function(pdf_doc) {
__PDF_DOC = pdf_doc;
__TOTAL_PAGES = __PDF_DOC.numPages;
// Hide the pdf loader and show pdf container in HTML
$("#pdf-loader").hide();
$("#pdf-contents").show();
$("#pdf-total-pages").text(__TOTAL_PAGES);
// Show the first page
showPage(1);
}).catch(function(error) {
// If error re-show the upload button
$("#pdf-loader").hide();
$("#upload-button").show();
alert(error.message);
});;
}
function showPage(page_no) {
__PAGE_RENDERING_IN_PROGRESS = 1;
__CURRENT_PAGE = page_no;
// Disable Prev & Next buttons while page is being loaded
$("#pdf-next, #pdf-prev").attr('disabled', 'disabled');
// While page is being rendered hide the canvas and show a loading message
$("#pdf-canvas").hide();
$("#page-loader").show();
// Update current page in HTML
$("#pdf-current-page").text(page_no);
// Fetch the page
__PDF_DOC.getPage(page_no).then(function(page) {
// As the canvas is of a fixed width we need to set the scale of the viewport accordingly
var scale_required = __CANVAS.width / page.getViewport(1).width;
// Get viewport of the page at required scale
var viewport = page.getViewport(scale_required);
// Set canvas height
__CANVAS.height = viewport.height;
var renderContext = {
canvasContext: __CANVAS_CTX,
viewport: viewport
};
// Render the page contents in the canvas
page.render(renderContext).then(function() {
__PAGE_RENDERING_IN_PROGRESS = 0;
// Re-enable Prev & Next buttons
$("#pdf-next, #pdf-prev").removeAttr('disabled');
// Show the canvas and hide the page loader
$("#pdf-canvas").show();
$("#page-loader").hide();
});
});
}
// Upon click this should should trigger click on the #file-to-upload file input element
// This is better than showing the not-good-looking file input element
$("#upload-button").on('click', function() {
$("#file-to-upload").trigger('click');
});
// When user chooses a PDF file
$("#file-to-upload").on('change', function() {
// Validate whether PDF
if(['application/pdf'].indexOf($("#file-to-upload").get(0).files[0].type) == -1) {
alert('Error : Not a PDF');
return;
}
$("#upload-button").hide();
// Send the object url of the pdf
showPDF(URL.createObjectURL($("#file-to-upload").get(0).files[0]));
});
// Previous page of the PDF
$("#pdf-prev").on('click', function() {
if(__CURRENT_PAGE != 1)
showPage(--__CURRENT_PAGE);
});
// Next page of the PDF
$("#pdf-next").on('click', function() {
if(__CURRENT_PAGE != __TOTAL_PAGES)
showPage(++__CURRENT_PAGE);
});
</script>
</body>
</html>
