Develop Reference

ReferenceError: PDFJS is not defined Asp.net

I'm trying to display a pdf using canvas and PDF.JS Stable v.2.2.228 but when I execute my webform it shows this error in the console: ReferenceError: PDFJS is not defined.
I read something about the global PDFJS object being removed but I can't find the correct syntax [Kinda new in JS]. Any suggestion is very appreciated
I was following this example in case is needed : https://usefulangle.com/post/20/pdfjs-tutorial-1-preview-pdf-during-upload-wih-next-prev-buttons
Js code:
function showPDF(pdf_url) {
PDFJS.getDocument({ url: pdf_url }).then(function (pdf_doc) {
__PDF_DOC = pdf_doc;
__TOTAL_PAGES = __PDF_DOC.numPages;
// Show the first page
showPage(1);
}).catch(function (error) {
// If error re-show the upload button
alert(error.message);
});;
}
function showPage(page_no) {
__PAGE_RENDERING_IN_PROGRESS = 1;
__CURRENT_PAGE = page_no;
__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
};
page.render(renderContext).then(function () {
__PAGE_RENDERING_IN_PROGRESS = 0;
// Show the canvas and hide the page loader
$("#pdf-canvas").show();
});
});
}
function ValidateFileUpload() {
var fuData = document.getElementById('FileUpload1');
var FileUploadPath = fuData.value;
//To check if user upload any file
if (FileUploadPath == '') {
alert("Por favor subir un archivo");
} else {
var Extension = FileUploadPath.substring(
FileUploadPath.lastIndexOf('.') + 1).toLowerCase();
//The file uploaded is an image
if (Extension == "png" || Extension == "jpeg" || Extension == "jpg" || Extension == "gif" || Extension == "jfif") {
// To Display
if (fuData.files && fuData.files[0]) {
var reader = new FileReader();
reader.onload = function (e) {
$('#ImgPreview').attr('src', e.target.result);
//document.getElementById('ImgPreview').files[0].name;
var nombre= document.getElementById('ImgPreview').files[0].name;
document.querySelector('#LblFileupload').innerText = nombre;
}
reader.readAsDataURL(fuData.files[0]);
}
}
else if (Extension == "pdf") {
var __PDF_DOC,
__CURRENT_PAGE,
__TOTAL_PAGES,
__PAGE_RENDERING_IN_PROGRESS = 0,
__CANVAS = $('#pdf-canvas').get(0),
__CANVAS_CTX = __CANVAS.getContext('2d');
showPDF(URL.createObjectURL($("#FileUpload1").get(0).files[0]));
}
//The file upload is NOT an image
else {
alert("Solo se aceptan archivos en formato .JPG - .PNG - .JPEG - .GIF - .JFIF");
}
}
}
HTML :
<asp:FileUpload ID="FileUpload1" runat="server" accept="image/*" onchange="return ValidateFileUpload()" Visible="true" />
<asp:Image ID="ImgPreview" runat="server" Height="600px" Width="500px" />
<canvas id="pdf-canvas" width="400"> </canvas>

You should change PDFJS to pdfjsLib. Also you should try adding the lines var __CANVAS = $('#pdf-canvas').get(0); and var __CANVAS_CTX = __CANVAS.getContext('2d'); under __CURRENT_PAGE = page_no; in that function because you're not initializing those variables before you try to call and use them. Also you need to add var in front of the other two items you're using in that function at the top.
So it should look like:
pdfjsLib.getDocument(URL.createObjectURL($("#FileUpload1").get(0).files[0])).then(doc => {
console.log("This file has " + doc._pdfInfo.numPages + "pages");
doc.getPage(1).then(page => {
var myCanvas = document.getElementById('pdf-canvas');
var context = myCanvas.getContext('2d');
var viewport = page.getViewport(1);
myCanvas.width = viewport.width;
myCanvas.height = viewport.height;
page.render({
canvasContext: context,
viewport : viewport
}
);
});
});

How to detect, that drawing a canvas object is finished?

I have following JS code (found here, on stackoverflow, and a little-bit modded), which resize image on client side using canvas.
function FileListItem(a) {
// Necesary to proper-work of CatchFile function (especially image-resizing).
// Code by Jimmy Wärting (https://github.com/jimmywarting)
a = [].slice.call(Array.isArray(a) ? a : arguments)
for (var c, b = c = a.length, d = !0; b-- && d;) d = a[b] instanceof File
if (!d) throw new TypeError('expected argument to FileList is File or array of File objects')
for (b = (new ClipboardEvent('')).clipboardData || new DataTransfer; c--;) b.items.add(a[c])
return b.files
}
function CatchFile(obj) {
// Based on ResizeImage function.
// Original code by Jimmy Wärting (https://github.com/jimmywarting)
var file = obj.files[0];
// Check that file is image (regex)
var imageReg = /[\/.](gif|jpg|jpeg|tiff|png|bmp)$/i;
if (!file) return
var uploadButtonsDiv = document.getElementById('upload_buttons_area');
// Check, that it is first uploaded file, or not
// If first, draw a div for showing status
var uploadStatusDiv = document.getElementById('upload_status_area');
if (!uploadStatusDiv) {
var uploadStatusDiv = document.createElement('div');
uploadStatusDiv.setAttribute('class', 'upload-status-area');
uploadStatusDiv.setAttribute('id', 'upload_status_area');
uploadButtonsDiv.parentNode.insertBefore(uploadStatusDiv, uploadButtonsDiv.nextSibling);
// Draw sub-div for each input field
var i;
for (i = 0; i < 3; i++) {
var uploadStatus = document.createElement('div');
uploadStatus.setAttribute('class', 'upload-status');
uploadStatus.setAttribute('id', ('upload_status_id_commentfile_set-' + i + '-file'));
uploadStatusDiv.append(uploadStatus);
}
}
var canvasDiv = document.getElementById('canvas-area');
var currField = document.getElementById(obj.id);
var currFieldLabel = document.getElementById(('label_' + obj.id));
// Main image-converting procedure
if (imageReg.test(file.name)) {
file.image().then(img => {
const canvas = document.createElement('canvas')
canvas.setAttribute('id', ('canvas_' + obj.id));
const ctx = canvas.getContext('2d')
const maxWidth = 1600
const maxHeight = 1200
// Calculate new size
const ratio = Math.min(maxWidth / img.width, maxHeight / img.height)
const width = img.width * ratio + .5|0
const height = img.height * ratio + .5|0
// Resize the canvas to the new dimensions
canvas.width = width
canvas.height = height
// Drawing canvas-object is necessary to proper-work
// on mobile browsers.
// In this case, canvas is inserted to hidden div (display: none)
ctx.drawImage(img, 0, 0, width, height)
canvasDiv.appendChild(canvas)
// Get the binary (aka blob)
canvas.toBlob(blob => {
const resizedFile = new File([blob], file.name, file)
const fileList = new FileListItem(resizedFile)
// Temporary remove event listener since
// assigning a new filelist to the input
// will trigger a new change event...
obj.onchange = null
obj.files = fileList
obj.onchange = CatchFile
}, 'image/jpeg', 0.70)
}
)
// If file is image, during conversion show status
function ShowConvertConfirmation() {
if (document.getElementById('canvas_' + obj.id)) {
document.getElementById(('upload_status_' + obj.id)).innerHTML =
'<font color="#4CAF50">Konwertowanie pliku ' + file.name + ' zakończone!</font>';
return true;
}
else {
document.getElementById(('upload_status_' + obj.id)).innerHTML =
'<font color="#4CAF50">Konwertowanie pliku ' + file.name + ' zakończone!</font>';
return false;
}
}
// Loop ShowConvertConfirmation function untill return true (file is converted)
var convertConfirmationLoop = setInterval(function() {
var isConfirmed = ShowConvertConfirmation();
if (!isConfirmed) {
ShowConvertConfirmation();
}
else {
// Break loop
clearInterval(convertConfirmationLoop);
}
}, 2000); // Check every 2000ms
}
// If file is not an image, show status with filename
else {
document.getElementById(('upload_status_' + obj.id)).innerHTML =
'<font color="#4CAF50">Dodano plik ' + file.name + '</font>';
//uploadStatusDiv.append(uploadStatus);
}
}
Canvas is drawn in hidden div:
<div id="canvas-area" style="overflow: hidden; height: 0;"></div>
I am only detect, that div canvas-area is presented and basing on this, JS append another div with status.
Unfortunatelly on some mobile devices (mid-range smartphones), message will be showed before finish of drawing (it is wrong). Due to this, some uploaded images are corrupted or stay in original size.
How to prevent this?

Everything that should happen after the image has loaded, should be executed within the then callback, or called from within it.
It is important to realise that the code that is not within that callback will execute immediately, well before the drawing has completed.

jQuery File Upload - get size of uploaded images

I am using the jQuery File Upload to upload product images. There are different "types" of images for each product (different size/dimensions).
I have altered the upload template so that a dropdown of possible image types is shown for each file added. Before clicking upload, the user must pick from the dropdown to indicate what image type the file being uploaded is.
Some image types are an exact size, some just have a minimum width. What I want to do is compare the actual image size to the type chosen to validate they are indicating the correct type.
I'm attempting to do this via the "fileuploadsubmit" callback where I have already added a check to make sure an option is selected in the dropdown.
$('#fileupload').bind('fileuploadsubmit', function (e, data) {
$('#uploading_note').removeClass("alert-danger").html("");
var inputs = data.context.find(':input');
if (inputs.filter(function () {
return !this.value && $(this).prop('required');
}).first().focus().length) {
data.context.addClass("alert-danger");
data.context.find('.file_msg').html("Image Type is required!");
data.context.find('button').prop('disabled', false);
return false;
}
var fixed_dimension = 0;
var wt = 0;
var ht = 0;
var image_size = getImageSize(data,function(width, height) {
wt = width;
ht = height;
console.log (wt+'x'+ht);
return [wt,ht];
});
...........
This is the getImageSize function.
function getImageSize(data,callback){
var img = new Image();
img.src = _URL.createObjectURL(data.files[0]);
img.onload = function () {
var w = this.width;
var h = this.height;
console.log(w+'-getImageSize-'+h);
callback (w,h);
};
}
The console.log() in both output correctly but I can't get these numbers outside the functions to use them. I understand it has to do with the functions be asynchronous but I can't figure out how to get around it. Or maybe there is a better jQuery File Upload built in option I'm missing.
I understand the asynchronous function issue, this one was attempt at finding a solution to validating the image size. I have also attempted to do this in the PHP script. It works in that I can prevent the upload of an image but the user experience is poor. So I am still looking for a solution as to how to do image size validation using jQuery File Upload.
Below is an update version of the code.
$('#fileupload').bind('fileuploadsubmit', function (e, data) {
console.log(data);
$('#uploading_note').removeClass("alert-danger").html("");
var inputs = data.context.find(':input');
if (inputs.filter(function () {
return !this.value && $(this).prop('required');
}).first().focus().length) {
console.log(data.context);
data.context.addClass("alert-danger");
data.context.find('.file_msg').html("Image Type is required!");
//$('#uploading_note').addClass("alert-danger").html("Image Type is required!");
data.context.find('button').prop('disabled', false);
return false;
}
var fixed_dimension = 0;
var wt = 0;
var ht = 0;
var image_size = getImageSize(data,function(width, height) {
wt = width;
ht = height;
console.log(wt+'-getImageSize-function'+ht);
switch (inputs[0].value){
case "16x9_background":
case "16x9":
var req_width = 1920;
var req_height = 1080;
fixed_dimension = 1;
break;
case "3x4":
var req_width = 1600;
var req_height = 1200;
fixed_dimension = 1;
break;
case "hires":
var req_width = 1400;
var req_height = 0;
break;
case "lowres":
var req_width = 200;
var req_height = 0;
break;
}
if (fixed_dimension){
if (wt != req_width || ht != req_height){
data.context.addClass("alert-danger");
data.context.find('.file_msg').html("Image dimensions must be exactly "+req_width+"x"+req_height+". This image is "+wt+"x"+ht+". Image not uploaded.");
return false;
}
} else {
if (wt < req_width){
data.context.addClass("alert-danger");
data.context.find('.file_msg').html("Image dimensions wrong!! Width must be "+req_width+", not "+wt+". Image not uploaded.");
console.log(wt+'x'+ht);
return false;
}
}
d = inputs.serializeArray();
d.push({ name: "folder", value: $('#barcode').val() });
d.push({ name: "stock_num", value: $('#stock_num').val() });
data.formData = d;
console.log(wt+"xxxx"+ht);
data.submit(); // SUMBIT THE FORM
});
console.log(wt+"xxxx"+ht);
console.log("imagesize:"+image_size);
return false; //STOP THE DEFAULT SUBMIT
});

What I ended up doing was removing the actual form submit button and replace it with a button (not type submit) that calls the validation code. If it passes, the form is then submitted normally (via data.submit()), if not it returns the error. I had to remove the file level submit buttons (or I found it easier to do that).
$('#fileupload').fileupload({
url: 'process.php',
previewThumbnail: true,
sequentialUploads: true,
acceptFileTypes: /(\.|\/)(jpe?g|pdf|zip)$/i,
maxChunkSize: 10000000,
add: function (e, data) {
$('#start_upload_button').click(function () {
getImageSize3(data).then(function(dimensions) {
image validation... return false if any errors
data.submit() // submit the form
});

Export Canvas content to PDF

I am working on something using HTML5 Canvas.
It's all working great, except right now, I can export the canvas content to PNG using Canvas2image. But I would like to export it to PDF. I've made some research and I'm pretty sure it's possible...but I can't seem to understand what I need to change in my code to make it work. I've read about a plugin called pdf.js...but I can't figure out how to implent it in my code.
First part :
function showDownloadText() {
document.getElementById("buttoncontainer").style.display = "none";
document.getElementById("textdownload").style.display = "block";
}
function hideDownloadText() {
document.getElementById("buttoncontainer").style.display = "block";
document.getElementById("textdownload").style.display = "none";
}
function convertCanvas(strType) {
if (strType == "PNG")
var oImg = Canvas2Image.saveAsPNG(oCanvas, true);
if (strType == "BMP")
var oImg = Canvas2Image.saveAsBMP(oCanvas, true);
if (strType == "JPEG")
var oImg = Canvas2Image.saveAsJPEG(oCanvas, true);
if (!oImg) {
alert("Sorry, this browser is not capable of saving " + strType + " files!");
return false;
}
oImg.id = "canvasimage";
oImg.style.border = oCanvas.style.border;
oCanvas.parentNode.replaceChild(oImg, oCanvas);
showDownloadText();
}
And the JS to that saves the image :
document.getElementById("convertpngbtn").onclick = function() {
convertCanvas("PNG");
}
document.getElementById("resetbtn").onclick = function() {
var oImg = document.getElementById("canvasimage");
oImg.parentNode.replaceChild(oCanvas, oImg);
hideDownloadText();
}
}

You need to use 2 plugins for this:
1) jsPDF
2) canvas-toBlob.js
Then add this piece of code to generate light weight PDF:
canvas.toBlob(function (blob) {
var url = window.URL || window.webkitURL;
var imgSrc = url.createObjectURL(blob);
var img = new Image();
img.src = imgSrc;
img.onload = function () {
var pdf = new jsPDF('p', 'px', [img.height, img.width]);
pdf.addImage(img, 0, 0, img.width, img.height);
pdf.save(fileName + '.pdf');
};
});

Look at this links:
http://www.codeproject.com/Questions/385045/export-html5-webpage-including-canvas-to-pdf
http://badassjs.com/post/708922912/pdf-js-create-pdfs-in-javascript
Most probably it will do the work you need

This jspdf is only useful in saving the file in the browser but we can't use that PDF generated to send to the server

Resizing dynamic images not working more than one time

I've got a little problem here. I've been trying to do an image gallery with JavaScript but there's something that I got a problem with. I can get the image to resize when the first image load, but as soon as I load another image, it won't resize anymore! Since the user will be able to upload a lot of different size pictures, I really need to make it work.
I've checked for ready-to-use image gallery and such and nothing was doing what I need to do.
Here's my javascript:
function changeCurrentImage(conteneur)
{
var img = conteneur.getElementsByTagName("img");
var imgUrl = img[0].src;
var imgFirstPart = imgUrl.substring(0, imgUrl.lastIndexOf('.') - 9);
var imgLastPart = imgUrl.substring(imgUrl.lastIndexOf('.'));
var currentImg = document.getElementById('currentImage');
currentImg.src = imgFirstPart + "borne" + imgLastPart;
resize(document.getElementById('currentImage'), 375, 655);
}
function resize(img, maxh, maxw) {
var ratio = maxh/maxw;
if (img.height/img.width > ratio){
// height is the problem
if (img.height > maxh){
img.width = Math.round(img.width*(maxh/img.height));
img.height = maxh;
}
} else {
// width is the problem
if (img.width > maxw){
img.height = Math.round(img.height*(maxw/img.width));
img.width = maxw;
}
}
};
Here's the HTML (using ASP.Net Repeater):
<asp:Repeater ID="rptImages" runat="server">
<HeaderTemplate>
</HeaderTemplate>
<ItemTemplate>
<a href="#">
<div id="thumbnailImageContainer1" onclick="changeCurrentImage(this)">
<div id="thumbnailImageContainer2">
<img id="thumbnailImage" src="<%# SiteUrl + Eval("ImageThumbnailPath")%>?rn=<%=Random()%>" alt="Photo" onload="resize(this, 60, 105)" />
</div>
</div>
</a>
</ItemTemplate>
<FooterTemplate>
</FooterTemplate>
</asp:Repeater>

Most likely the image is not yet downloaded so img.height and img.width are not yet there. Technically you don't need to wait till the whole image is downloaded, you can poll the image in a timer until width and height are non-zero. This sounds messy but can be done nicely if you take the time to do it right. (I have an ImageLoader utility I made for this purpose....has only one timer even if it is handling multiple images at once, and calls a callback function when it has the sizes) I have to disagree with Marcel....client side works great for this sort of thing, and can work even if the images are from a source other than your server.
Edit: add ImageLoader utility:
var ImageLoader = {
maxChecks: 1000,
list: [],
intervalHandle : null,
loadImage : function (callback, url, userdata) {
var img = new Image ();
img.src = url;
if (img.width && img.height) {
callback (img.width, img.height, url, 0, userdata);
}
else {
var obj = {image: img, url: url, callback: callback,
checks: 1, userdata: userdata};
var i;
for (i=0; i < this.list.length; i++) {
if (this.list[i] == null)
break;
}
this.list[i] = obj;
if (!this.intervalHandle)
this.intervalHandle = setInterval(this.interval, 30);
}
},
// called by setInterval
interval : function () {
var count = 0;
var list = ImageLoader.list, item;
for (var i=0; i<list.length; i++) {
item = list[i];
if (item != null) {
if (item.image.width && item.image.height) {
item.callback (item.image.width, item.image.height,
item.url, item.checks, item.userdata);
ImageLoader.list[i] = null;
}
else if (item.checks > ImageLoader.maxChecks) {
item.callback (0, 0, item.url, item.checks, item.userdata);
ImageLoader.list[i] = null;
}
else {
count++;
item.checks++;
}
}
}
if (count == 0) {
ImageLoader.list = [];
clearInterval (ImageLoader.intervalHandle);
delete ImageLoader.intervalHandle;
}
}
};
Example usage:
var callback = function (width, height, url, checks, userdata) {
// show stuff in the title
document.title = "w: " + width + ", h:" + height +
", url:" + url + ", checks:" + checks + ", userdata: " + userdata;
var img = document.createElement("IMG");
img.src = url;
// size it to be 100 px wide, and the correct
// height for its aspect ratio
img.style.width = "100px";
img.style.height = ((height/width)*100) + "px";
document.body.appendChild (img);
};
ImageLoader.loadImage (callback,
"http://upload.wikimedia.org/wikipedia/commons/thumb/" +
"1/19/Caerulea3_crop.jpg/800px-Caerulea3_crop.jpg", 1);
ImageLoader.loadImage (callback,
"http://upload.wikimedia.org/wikipedia/commons/thumb/" +
"8/85/Calliphora_sp_Portrait.jpg/402px-Calliphora_sp_Portrait.jpg", 2);

With the way you have your code setup, I would try and call your resize function from an onload event.
function resize() {
var img = document.getElementById('currentImage');
var maxh = 375;
var maxw = 655;
var ratio = maxh/maxw;
if (img.height/img.width > ratio){
// height is the problem
if (img.height > maxh){
img.width = Math.round(img.width*(maxh/img.height));
img.height = maxh;
}
} else {
// width is the problem
if (img.width > maxw){
img.height = Math.round(img.height*(maxw/img.width));
img.width = maxw;
}
}
};
function changeCurrentImage(conteneur)
{
var img = conteneur.getElementsByTagName("img");
img.onload = resize;
var imgUrl = img[0].src;
var imgFirstPart = imgUrl.substring(0, imgUrl.lastIndexOf('.') - 9);
var imgLastPart = imgUrl.substring(imgUrl.lastIndexOf('.'));
var currentImg = document.getElementById('currentImage');
currentImg.src = imgFirstPart + "borne" + imgLastPart;
}
I would play around with that. Maybe use global variables for your maxH/W and image ID(s);

#Comments: No, I can't do that server side since it would refresh the page everytime someone click on a new image. That would be way too bothersome and annoying for the users.
As for the thumbnails, those image are already saved in the appropriate size. Only the big image that shows is about 33% of its size. Since we already have 3 images PER uploaded images, I didn't want to upload a 4th one for each upload, that would take too much server space!
As for the "currentImage", I forgot to add it, so that might be helful lol:
<div id="currentImageContainer">
<div id="currentImageContainer1">
<div id="currentImageContainer2">
<img id="currentImage" src="#" alt="" onload="resize(this, 375, 655)" />
</div>
</div>
</div>
#rob: I'll try the ImageLoader class, that might do the trick.

I found an alternative that is working really well. Instead of changing that IMG width and height, I delete it and create a new one:
function changeCurrentImage(conteneur)
{
var thumbnailImg = conteneur.getElementsByTagName("img");
var thumbnailImgUrl = thumbnailImg[0].src;
var newImgUrl = thumbnailImgUrl.replace("thumbnail", "borne");
var currentImgDiv = document.getElementById('currentImageContainer2');
var currentImg = currentImgDiv.getElementById("currentImage");
if (currentImg != null)
{
currentImgDiv.removeChild(currentImg);
}
var newImg = document.createElement("img");
newImageDiv = document.getElementById('currentImageContainer2');
newImg.id = "currentImage";
newImg.onload = function() {
Resize(newImg, 375, 655);
newImageDiv.appendChild(newImg);
}
newImg.src = newImgUrl;
}
Also, in case people wonder, you MUST put the .onload before the .src when assigning an a new source for an image!