Develop Reference

jsPDF autoTable not displaying images with original dimensions properly in PDF

My HTML table displays dynamic images properly on the webpage, however, an attempt to generate a PDF using jsPDF following this example created on codepen is failing me. I'm getting the below pdf without the image filling the entire width and the height appears to be reduced instead of getting the original image size- I'm using base64:
I have also looked at several questions and answers here on SO and elsewhere extensively with no avail like this one here How to get table row image in PDF using jsPDF? and followed this discussion here https://github.com/simonbengtsson/jsPDF-AutoTable/issues/173, but I don't seem to wrap my head around this.
function createPdf(){
var doc = new jsPDF();
doc.autoTable({
html: '#mytable',
bodyStyles: {minCellHeight : 30},
didDrawCell: function(data){
if(data.cell.section ==='body' && data.column.index ===1) {
var td = data.cell.raw;
var img = td.getElementsByTagName('img')[0];
var dim = data.cell.height - data.cell.padding('vertical');
var textPos = data.cell.textPos;
doc.addImage(img.src, textPos.x, textPos.y, dim, dim);
}
}
})
doc.save("table.pdf");
}
The issue appears to do with the width and height dimensions which is dynamic and also the images are further on the right. However, the priority issue is to set auto value for height to provide desirable outcome.
Anyone with expertise in this, kindly Check what I have used here https://jsfiddle.net/kibika2020/0rtoph6s/5/
function createPdf(){
var doc = new jsPDF();
doc.autoTable({
html: '#mytable',
bodyStyles: {minCellHeight : 50},
didDrawCell: function(data){
if(data.cell.section ==='body' && data.column.index ===1) {
var td = data.cell.raw;
var img = td.getElementsByTagName('img')[0];
var dim = data.cell.height - data.cell.padding('vertical');
var textPos = data.cell.textPos;
doc.addImage(img.src, textPos.x, textPos.y, dim, dim);
}
}
})
doc.save("autoble.pdf");
}
I'm a beginner and finding this jsPDF stuff really tough than I expected. Take a look and advise me accordingly.
Thank you.

I would like to merge all images within DIV and allow user to download (js powered)

I'm working on a client's web design and development powered by Wordpress and Woocommerce, the plugin is great but there's a few functions I wish it had. The main one is giving the ability for the user to save the preview of their configuration.
The plug-in is 'Woocommerce Visual Products Configurator':
It allows buyers to build their own item by selecting from a series of different attributes for different parts of an item. Ex, choosing different types of Soles for a shoe, as well as being able to choose from a series of laces for the same shoe.
My Issue: The configuration images are layered on top of each other as the user selects their options so any normal "save as" function will just save the top image.
I have succesfully managed to combine and save the images using html2canvas-Data URL() but the way it generates the screenshots means the quality becomes very poor.
My thoughts are to merge all the images within the "vpc-preview" DIV then force the download.
Hunting through the functions of the plugin I found this:
function merge_pictures($images, $path = false, $url = false) {
$tmp_dir = uniqid();
$upload_dir = wp_upload_dir();
$generation_path = $upload_dir["basedir"] . "/VPC";
$generation_url = $upload_dir["baseurl"] . "/VPC";
if (wp_mkdir_p($generation_path)) {
$output_file_path = $generation_path . "/$tmp_dir.png";
$output_file_url = $generation_url . "/$tmp_dir.png";
foreach ($images as $imgs) {
list($width, $height) = getimagesize($imgs);
$img = imagecreatefrompng($imgs);
imagealphablending($img, true);
imagesavealpha($img, true);
if (isset($output_img)) {
imagecopy($output_img, $img, 0, 0, 0, 0, 1000, 500);
} else {
$output_img = $img;
imagealphablending($output_img, true);
imagesavealpha($output_img, true);
imagecopymerge($output_img, $img, 10, 12, 0, 0, 0, 0, 100);
}
}
imagepng($output_img, $output_file_path);
imagedestroy($output_img);
if ($path)
return $output_file_path;
if ($url)
return $output_file_url;
} else
return false;
}
However the function isn't called anywhere. There's also a couple of "save" buttons that are commented out which makes me wonder if they removed from a previous build.
Ideally I'd like the user to be able to instantly share their creation to facebook but thought this would be a good start.
Any ideas would be greatly appreciated!
Thanks!
UPDATE:
I've managed to use the following code to output an alert of the url's of each of the config images. Useless for the user but at least I know it's targeting exactly what I need.
function img_find() {
var imgs = document.querySelectorAll('#vpc-preview img');
var imgSrcs = [];
for (var i = 0; i < imgs.length; i++) {
imgSrcs.push(imgs[i].src);
}
return alert(imgSrcs);
}
Any suggestions on how to manipulate this and merge the corresponding image of each URL then force the download?
Cick to see Fiddle
UPDATE 2: The following fiddle lets users upload images and then merges them into a single photo for download. Unfortunately my coding skills aren't good enough to manipulate this into using the SRC urls of images within certain DIV and to Merge all the photos on top of each other.
Fiddle
function addToCanvas(img) {
// resize canvas to fit the image
// height should be the max width of the images added, since we rotate -90 degree
// width is just a sum of all images' height
canvas.height = max(lastHeight, img.width);
canvas.width = lastWidth + img.height;
ctx.clearRect(0, 0, canvas.width, canvas.height);
if (lastImage) {
ctx.drawImage(lastImage, 0, canvas.height - lastImage.height);
}
ctx.rotate(270 * Math.PI / 180); // rotate the canvas to the specified degrees
ctx.drawImage(img, -canvas.height, lastWidth);
lastImage = new Image();
lastImage.src = canvas.toDataURL();
lastWidth += img.height;
lastHeight = canvas.height;
imagesLoaded += 1;
}

Based on this question/answer, I would take a look at node-canvas.

What I have done in the past is use a #print css file to only capture the divs needed. Very simple concept but works well.
After looking at your link, that is exactly the situations I use it in..online designers. It is a little more difficult keeping your layers responsively aligned, but in the end I feel your codes become cleaner and it works well across devices and OS'.
If you dont want PDF and a simple preview and download than html2image.js is perfect.
$(document).ready(function(){
var element = $("#html-content-holder"); // global variable
var getCanvas; // global variable
$("#btn-Preview-Image").on('click', function () {
html2canvas(element, {
onrendered: function (canvas) {
$("#previewImage").append(canvas);
getCanvas = canvas;
}
});
});
$("#btn-Convert-Html2Image").on('click', function () {
var imgageData = getCanvas.toDataURL("image/png");
// Now browser starts downloading it instead of just showing it
var newData = imgageData.replace(/^data:image\/png/, "data:application/octet-stream");
$("#btn-Convert-Html2Image").attr("download", "your_pic_name.png").attr("href", newData);
});
});
<script src="https://github.com/niklasvh/html2canvas/releases/download/0.4.1/html2canvas.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<div id="html-content-holder" style="background-color: #F0F0F1; color: #00cc65; width: 500px;
padding-left: 25px; padding-top: 10px;">
Place any code here
</div>
<input id="btn-Preview-Image" type="button" value="Preview"/>
<a id="btn-Convert-Html2Image" href="#">Download</a>
<br/>
<h3>Preview :</h3>
<div id="previewImage">
</div>
For High quality you want to use rasterizeHTML.js
Found here:
https://github.com/cburgmer/rasterizeHTML.js/blob/master/examples/retina.html

Firefox drawing blank Canvas when restoring from saved base64

I am working with a single canvas that allows the user to click on a window pane in a window image. The idea is to show where the user has clicked. The image will then be modified (by drawing a grill on the window) and then saved to in JPEG. I am saving the canvas image prior to the click function because I don't want the selection box to show in the final image. However, Firefox often displays a blank canvas when restoring the canvas where IE and Chrome do not. This works perfectly in Chrome and IE. Any suggestions? Does Firefox have a problem with toDataURL()? Maybe some async issue going on here? I am also aware that saving a canvas in this fashion is memory intensive and there may be a better way to do this but I'm working with what I have.
Code:
/**
* Restores canvas from drawingView.canvasRestorePoint if there are any restores saved
*/
restoreCanvas:function()
{
var inverseScale = (1/drawingView.scaleFactor);
var canvas = document.getElementById("drawPop.canvasOne");
var c = canvas.getContext("2d");
if (drawingView.canvasRestorePoint[0]!=null)
{
c.clearRect(0,0,canvas.width,canvas.height);
var img = new Image();
img.src = drawingView.canvasRestorePoint.pop();
c.scale(inverseScale,inverseScale);
c.drawImage(img, 0, 0);
c.scale(drawingView.scaleFactor, drawingView.scaleFactor);
}
},
/**
* Pushes canvas into drawingView.canvasRestorePoint
*/
saveCanvas:function()
{
var canvas = document.getElementById("drawPop.canvasOne");
var urlData = canvas.toDataURL();
drawingView.canvasRestorePoint.push(urlData);
},
EXAMPLE OF USE:
readGrillInputs:function()
{
var glassNum = ir.get("drawPop.grillGlassNum").value;
var panelNum = ir.get("drawPop.grillPanelNum").value;
drawingView.restoreCanvas();
drawEngine.drawGrill(glassNum, panelNum,null);
drawingView.saveCanvas();
},
sortClick:function(event)
{
..... //Sorts where user has clicked and generates panel/glass num
.....
drawingView.showClick(panelNum, glassNum);
},
showClick:function(panelNum, glassNum)
{
var glass = item.panels[panelNum].glasses[glassNum];
var c = drawEngine.context;
drawingView.restoreCanvas();
drawingView.saveCanvas();
c.strokeStyle = "red";
c.strokeRect(glass.x, glass.y, glass.w, glass.h);
},

By just looking at the code setting the img.src is an async action to retrieve the image, so when you try to draw it 2 lines later to the canvas, it probably hasn't been loaded yet (having it in cache will make it return fast enough that it might work).
You should instead use an img.onload function to draw the image when it has loaded.
restoreCanvas:function()
{
var inverseScale = (1/drawingView.scaleFactor);
var canvas = document.getElementById("drawPop.canvasOne");
var c = canvas.getContext("2d");
if (drawingView.canvasRestorePoint[0]!=null)
{
c.clearRect(0,0,canvas.width,canvas.height);
var img = new Image();
img.onload = function() {
c.scale(inverseScale,inverseScale);
c.drawImage(img, 0, 0);
c.scale(drawingView.scaleFactor, drawingView.scaleFactor);
};
img.src = drawingView.canvasRestorePoint.pop();
}
},

jQuery and Canvas loading behaviour

After being a long time lurker, this is my first post here! I've been RTFMing and searching everywhere for an answer to this question to no avail. I will try to be as informative as I can, hope you could help me.
This code is for my personal webpage.
I am trying to implement some sort of a modern click-map using HTML5 and jQuery.
In the website you would see the main image and a hidden canvas with the same size at the same coordinates with this picture drawn into it.
When the mouse hovers the main picture, it read the mouse pixel data (array of r,g,b,alpha) from the image drawn onto the canvas. When it sees the pixel color is black (in my case I only check the RED value, which in a black pixel would be 0) it knows the activate the relevant button.
(Originally, I got the idea from this article)
The reason I chose this method, is for the page to be responsive and dynamically change to fit different monitors and mobile devices. To achieve this, I call the DrawCanvas function every time the screen is re-sized, to redraw the canvas with the new dimensions.
Generally, this works OK. The thing is ,there seems to be an inconsistent behavior in Chrome and IE(9). When I initially open the page, I sometimes get no pixel data (0,0,0,0), until i re-size the browser. At first I figured there's some loading issues that are making this happen so I tried to hack it with setTimeout, it still doesn't work. I also tried to trigger the re-size event and call the drawCanvas function at document.ready, still didn't work.
What's bothering me is most, are the inconsistencies. Sometimes it works, sometimes is doesn't. Generally, it is more stable in chrome than in IE(9).
Here is the deprecated code:
<script type="text/javascript">
$(document).ready(function(){setTimeout(function() {
// Get main image object
var mapWrapper = document.getElementById('map_wrapper').getElementsByTagName('img').item(0);
// Create a hidden canvas the same size as the main image and append it to main div
var canvas = document.createElement('canvas');
canvas.height = mapWrapper.clientHeight;
canvas.width = mapWrapper.clientWidth;
canvas.fillStyle = 'rgb(255,255,255)';
canvas.style.display = 'none';
canvas.id = 'hiddencvs';
$('#map_wrapper').append(canvas);
// Draw the buttons image into the canvas
drawCanvas(null);
$("#map_wrapper").mousemove(function(e){
var canvas = document.getElementById('hiddencvs');
var context = canvas.getContext('2d');
var pos = findPos(this);
var x = e.pageX - pos.x;
var y = e.pageY - pos.y;
// Get pixel information array (red, green, blue, alpha)
var pixel = context.getImageData(x,y,1,1).data;
var red = pixel[0];
var main_img = document.getElementById('map_wrapper').getElementsByTagName('img').item(0);
if (red == 0)
{
...
}
else {
...
}
});
},3000);}); // End DOM Ready
function drawCanvas(e)
{
// Get context of hidden convas and set size according to main image
var cvs = document.getElementById('hiddencvs');
var ctx = cvs.getContext('2d');
var mapWrapper = document.getElementById('map_wrapper').getElementsByTagName('img').item(0);
cvs.width = mapWrapper.clientWidth;
cvs.height = mapWrapper.clientHeight;
// Create img element for buttons image
var img = document.createElement("img");
img.src = "img/main-page-buttons.png";
// Draw buttons image inside hidden canvas, strech it to canvas size
ctx.drawImage(img, 0, 0,cvs.width,cvs.height);
}
$(window).resize(function(e){
drawCanvas(e);
}
);
function findPos(obj)
{
...
}
</script>
I'd appreciate any help!
Thanks!
Ron.

You don't wait for the image to be loaded so, depending on the cache, you may draw an image or not in the canvas.
You should do this :
$(function(){
var img = document.createElement("img");
img.onload = function() {
var mapWrapper = document.getElementById('map_wrapper').getElementsByTagName('img').item(0);
...
// your whole code here !
...
}
img.src = "img/main-page-buttons.png";
});

converting Div to Canvas options [duplicate]

It would be incredibly useful to be able to temporarily convert a regular element into a canvas. For example, say I have a styled div that I want to flip. I want to dynamically create a canvas, "render" the HTMLElement into the canvas, hide the original element and animate the canvas.
Can it be done?

There is a library that try to do what you say.
See this examples and get the code
http://hertzen.com/experiments/jsfeedback/
http://html2canvas.hertzen.com/
Reads the DOM, from the html and render it to a canvas, fail on some, but in general works.

Take a look at this tutorial on MDN: https://developer.mozilla.org/en/HTML/Canvas/Drawing_DOM_objects_into_a_canvas (archived)
Its key trick was:
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
var data = '<svg xmlns="http://www.w3.org/2000/svg" width="200" height="200">' +
'<foreignObject width="100%" height="100%">' +
'<div xmlns="http://www.w3.org/1999/xhtml" style="font-size:40px">' +
'<em>I</em> like ' +
'<span style="color:white; text-shadow:0 0 2px blue;">' +
'cheese</span>' +
'</div>' +
'</foreignObject>' +
'</svg>';
var DOMURL = window.URL || window.webkitURL || window;
var img = new Image();
var svg = new Blob([data], {type: 'image/svg+xml;charset=utf-8'});
var url = DOMURL.createObjectURL(svg);
img.onload = function () {
ctx.drawImage(img, 0, 0);
DOMURL.revokeObjectURL(url);
}
img.src = url;
That is, it used a temporary SVG image to include the HTML content as a "foreign element", then renders said SVG image into a canvas element. There are significant restrictions on what you can include in an SVG image in this way, however. (See the "Security" section for details — basically it's a lot more limited than an iframe or AJAX due to privacy and cross-domain concerns.)

Sorry, the browser won't render HTML into a canvas.
It would be a potential security risk if you could, as HTML can include content (in particular images and iframes) from third-party sites. If canvas could turn HTML content into an image and then you read the image data, you could potentially extract privileged content from other sites.
To get a canvas from HTML, you'd have to basically write your own HTML renderer from scratch using drawImage and fillText, which is a potentially huge task. There's one such attempt here but it's a bit dodgy and a long way from complete. (It even attempts to parse the HTML/CSS from scratch, which I think is crazy! It'd be easier to start from a real DOM node with styles applied, and read the styling using getComputedStyle and relative positions of parts of it using offsetTop et al.)

You can use dom-to-image library (I'm the maintainer).
Here's how you could approach your problem:
var parent = document.getElementById('my-node-parent');
var node = document.getElementById('my-node');
var canvas = document.createElement('canvas');
canvas.width = node.scrollWidth;
canvas.height = node.scrollHeight;
domtoimage.toPng(node).then(function (pngDataUrl) {
var img = new Image();
img.onload = function () {
var context = canvas.getContext('2d');
context.translate(canvas.width, 0);
context.scale(-1, 1);
context.drawImage(img, 0, 0);
parent.removeChild(node);
parent.appendChild(canvas);
};
img.src = pngDataUrl;
});
And here is jsfiddle

Building on top of the Mozdev post that natevw references I've started a small project to render HTML to canvas in Firefox, Chrome & Safari. So for example you can simply do:
rasterizeHTML.drawHTML('<span class="color: green">This is HTML</span>'
+ '<img src="local_img.png"/>', canvas);
Source code and a more extensive example is here.

No such thing, sorry.
Though the spec states:
A future version of the 2D context API may provide a way to render fragments of documents, rendered using CSS, straight to the canvas.
Which may be as close as you'll get.
A lot of people want a ctx.drawArbitraryHTML/Element kind of deal but there's nothing built in like that.
The only exception is Mozilla's exclusive drawWindow, which draws a snapshot of the contents of a DOM window into the canvas. This feature is only available for code running with Chrome ("local only") privileges. It is not allowed in normal HTML pages. So you can use it for writing FireFox extensions like this one does but that's it.

You could spare yourself the transformations, you could use CSS3 Transitions to flip <div>'s and <ol>'s and any HTML tag you want. Here are some demos with source code explain to see and learn: http://www.webdesignerwall.com/trends/47-amazing-css3-animation-demos/

the next code can be used in 2 modes, mode 1 save the html code to a image, mode 2 save the html code to a canvas.
this code work with the library: https://github.com/tsayen/dom-to-image
*the "id_div" is the id of the element html that you want to transform.
**the "canvas_out" is the id of the div that will contain the canvas
so try this code.
:
function Guardardiv(id_div){
var mode = 2 // default 1 (save to image), mode 2 = save to canvas
console.log("Process start");
var node = document.getElementById(id_div);
// get the div that will contain the canvas
var canvas_out = document.getElementById('canvas_out');
var canvas = document.createElement('canvas');
canvas.width = node.scrollWidth;
canvas.height = node.scrollHeight;
domtoimage.toPng(node).then(function (pngDataUrl) {
var img = new Image();
img.onload = function () {
var context = canvas.getContext('2d');
context.drawImage(img, 0, 0);
};
if (mode == 1){ // save to image
downloadURI(pngDataUrl, "salida.png");
}else if (mode == 2){ // save to canvas
img.src = pngDataUrl;
canvas_out.appendChild(img);
}
console.log("Process finish");
});
}
so, if you want to save to image just add this function:
function downloadURI(uri, name) {
var link = document.createElement("a");
link.download = name;
link.href = uri;
document.body.appendChild(link);
link.click();
}
Example of use:
<html>
<head>
</script src="/dom-to-image.js"></script>
</head>
<body>
<div id="container">
All content that want to transform
</div>
<button onclick="Guardardiv('container');">Convert<button>
<!-- if use mode 2 -->
<div id="canvas_out"></div>
</html>
Comment if that work.
Comenten si les sirvio :)

The easiest solution to animate the DOM elements is using CSS transitions/animations but I think you already know that and you try to use canvas to do stuff CSS doesn't let you to do. What about CSS custom filters? you can transform your elements in any imaginable way if you know how to write shaders. Some other link and don't forget to check the CSS filter lab.
Note: As you can probably imagine browser support is bad.

function convert() {
dom = document.getElementById('divname');
var script,
$this = this,
options = this.options,
runH2c = function(){
try {
var canvas = window.html2canvas([ document.getElementById('divname') ], {
onrendered: function( canvas ) {
window.open(canvas.toDataURL());
}
});
} catch( e ) {
$this.h2cDone = true;
log("Error in html2canvas: " + e.message);
}
};
if ( window.html2canvas === undefined && script === undefined ) {
} else {.
// html2canvas already loaded, just run it then
runH2c();
}
}