I am using toDataURL() method of a canvas object. It works on IE9 and Chrome.
But it is not supporting for IE7 and IE8. I found this link
https://github.com/sampula/SVG.toDataURL/commit/9b59af148b7f14d41974cf318eed6f84c8c91062
It extends SVG to use toDataURL(). But in its implementation, it again uses canvas.toDataURL(). I am using Google's API (jquery.flot.js) for plotting all the graphs graphs. But it also uses canvas to plot the graph. So, SVG is not an option.
I there ever a way to use canvas.toDataURL() or something similar for IE7 and IE8.
Thanks in advance
IE7/8 does not support either Canvas or SVG.
It does however support VML, which is a vector language similar to SVG, and there are a number of javascript-based hacks for IE that use its VML functionality to emulate both Canvas and SVG in this older browser.
The most well known IE-Canvas hack is this one: http://code.google.com/p/explorercanvas/
I haven't spent much time with it myself, so I can't vouch for whether it can do specific functionality such as the toDataURL() method you're asking about, but if you can't do it with this, then it's unlikely to be possible at all.
I mentioned that there are similar tools for VML->SVG as well. If that's of interest to you, then you might want to look into this one: http://code.google.com/p/svg2vml/
Bear in mind that no matter how clever these hacks are, there is always a fundamental issue of performance. IE7/8's javascript interpreter is very slow by modern standards, and these are javascript-based tools trying to shoehorn very modern functionality into this old browser. They may well work, but don't try to do anything too clever with your canvas or SVG, or you'll kill the browser.
Finally, since you mentioned that you're using all this to draw graphs, I will point out the graphing module of the Raphael library. Raphael is a library which draws SVG graphics on all browsers (falling back to VML for IE). The graphing module provides all the usual graph types, wrapped in an extremely easy-to-use javascript API. And it is fully cross-browser compatible -- it works on all desktop browsers out of the box from the latest Chrome and Firefox all the way back to IE6. If you're struggling with cross-browser compatibility with the tools you're using now, you may want to switch to this library.
Hope that helps.
I have recently created an application in which I had to use toDataURL() but I was not able to find any way to do this in IE7/8. My application was an online image editor in which user was able to save the canvas contents. I believe there is not way we can use this method in IE7/8.
Related
I'm creating a web portal with maps in SVG format and set in the HTML code using <object> tag in order to preserve the possibility of interactivity. My main problem is how to create and support an interactive SVG format in the browser?
As far as I have researched there are several options:
SMIL animation directly in SVG,
CSS animation,
JavaScript libraries.
It seems to me that this last option has the most potential. There are many libraries (Snap.svg, svg.js, Velocity.js, d3.js, jVectorMap.js, GreenSock ....) to use, so I would appreciate if someone could give some tips on which of them to use.
Do I need to use them within the SVG directly using the <script> tag or using an external .js file? To my knowledge, jQuery can't be used directly within SVG.
In fact, all three variants work more or less with different advantages and drawbacks.
1. SMIL
SMIL is easy to use inside of your SVG and allows modifying attributes of your SVG object directly. However, if you want/need to support Internet Explorer or Edge, you don't have much luck (see CanIUse).
Chrome 45 deprecated SMIL in favor of CSS animations and Web animations. But the Chrome developers recently suspended their intent (see this StackOverflow answer).
2. CSS Animations
These are a good alternative for animation of SVGs. The implementation is normally very fast and smooth, as far as I saw it. Browser support is better especially with Microsoft Browsers. So I would really recommend it.
If you need some more user interaction, you get to the limits of CSS animations quickly. Some interaction is possible, but if you want more, you need JavaScript.
3. JavaScript libraries
jQuery really have serious problems with SVGs, but I think it is better doing without jQuery (for both, jQuery and your software) because if it would support SVGs, it would be even larger and slower. However, if you already have jQuery included, it is possible to select elements and then animate them without jQuery.
Other libraries are more specialized for SVG and work really great (I myself worked with d3.js with good results).
Recommendation
If you don't need to support Microsoft browsers, then SMIL can be an easy and compact way to define certain animations.
If you need those browsers, I would recommend trying CSS animations. But if that seems too static, one of the JavaScript libraries may help.
What are the main differences between raphael.js and paper.js?
Are there any other libs out there I should look at? Any like these that focus more on CSS3 then SVG?
Thanks!
Raphael uses SVG. Paper use Canvas.
That's the major difference.
In terms of what you can do with them, Canvas and SVG each have their own place, and are good for different things (although they are both capable of doing each other's thing as well if you ask them to). From a purely functional point of view, you need to consider what you want to do with the library before you decide which one you go with.
Browser compatibility is going to be a big issue, whichever one you use. This will possibly be a bigger issue than functionality, in fact.
Raphael has an advantage on the desktop because it detects older versions of IE (as far back as IE6) and falls back to using VML instead of SVG. This means it has excellent compatibility on virtualyl all desktop browsers. Canvas simply isn't supported on older IEs, and the Paper.js people don't really seem too worried about it.
But on mobiles, Paper.js may be better, because Canvas has much better support on mobiles than SVG. SVG isn't supported on most Android devices at all. This is changing: Android 3.0 introduced SVG support, but most Android devices being sold even now come with v2.x, so it'll be a while before you can rely on SVG working on a mobile.
For more info about browser support, see the CanIUse site:
CanIUse SVG
CanIUse Canvas
Hope that helps.
The most obvious difference is that Raphael targets SVG, and Paper targets the Canvas element. It also appears that Paper has far greater advanced features, whereas Raphael is just core SVG elements, which can then be expanded upon with plugins. Arguably, it depends more on your need, and which environments you wish to target. Canvas works well on some mobile browsers, SVG barely works on mobile environments at all.
As another side note: SVG, as I'm aware of it, is not hardware-accelerated in IE (9) or Firefox, and, again if my memory isn't failing me, Canvas is, at least in IE (9). As for IE 8 and below, you need a browser plugin, which most have, but it is a dependency to expect.
Are there any other libs out there I should look at?
Yes, you should have a look at processing.js!
And by the way - here is an excellent comparison between raphael.js, paper.js and processing.js:
http://coding.smashingmagazine.com/2012/02/22/web-drawing-throwdown-paper-processing-raphael/
And even code comparison of the same effect:
http://zgrossbart.github.com/3gears/
Are there any other libs out there I should look at?
If you have experience in Flash development you might consider easel.js which provides you with some of the flash display mechanisms. Easel looks like a really nice lib to me.
Another interesting library is processingjs, unlike the other libs processingjs also does 3d stuff. (It's also good at 2d.) Unlike paper, raphael and easel processing doesn't handle user interaction out of the box.
Both libraries use canvas.
I really want something that is eye catching and modern. I like how Digg does the Digg swarm (http://labs.digg.com/swarm/)
Have a look at
http://raphaeljs.com/
a small JavaScript library that should simplify your work with vector graphics on the web. If you want to create your own specific chart or image crop and rotate widget, for example, you can achieve it simply and easily with this library.
I don't know if it is the best.
Take a look at flot; http://code.google.com/p/flot/. You can check out some pretty cool-looking implementations of flot, here.
Flot is a pure Javascript plotting
library for jQuery. It produces
graphical plots of arbitrary datasets
on-the-fly client-side.
The focus is on simple usage (all
settings are optional), attractive
looks and interactive features like
zooming and mouse tracking.
The plugin works with Internet
Explorer 6/7/8, Firefox 2.x+, Safari
3.0+, Opera 9.5+ and Konqueror 4.x+ with the HTML canvas tag (the excanvas
Javascript emulation helper is used
for IE).
Protovis is an option.
Edit:
The team behind Protovis has since created D3, so this is likely a better option than Protovis.
I found a vector library on the Internet that even works with IE6!
http://raphaeljs.com/index.html
It's amazing.
Now my question is it better than the upcoming HTML5 <canvas>? The only reason I ask is that it could be years before Microsoft implements a <canvas> that doesn't require a plugin for it to run.
And it will be even longer until all the IE users on the Internet get rid of their old browsers so that we can even justify using the HTML5 <canvas>.
I'm all about sticking to standards, but this one is just going to take too long, thanks to MS's slow development of their browser.
Thoughts?
Raphael is a vector graphics library, done using SVG, whereas HTML5 canvas is bitmap graphics.
If you want to do vector graphics, I think going with Raphael is probably a good choice over "just" canvas. As you say, canvas does not quite work with IE and it will probably be a while before it's natively supported. If Raphael does what you need, there is no particular reason not to use it.
Do note that there are also other libraries for this: Excanvas, which emulates canvas for IE using VML (as far as I know), and also some others which do the same with Silverlight and Flash but I forgot their names.
There's also Dojo, which has a component for abstracting canvas usage behind an easy to use interface, which also supports IE.
Having native canvas in all browsers will not make the libraries obsolete, since the libraries usually abstract some of the canvas complexities away, making the usage easier.
SVGWeb (http://code.google.com/p/svgweb/) by Google is what you want. It makes IE compatible with SVG, which is the standard, and which all other mainstream browsers already support. In other words, as google say, "Using the library plus native SVG support you can instantly target ~95% of the existing installed web base."
And you can use http://code.google.com/p/explorercanvas/ which implements the HTML5 Canvas Standard in IE. All you do is add:
<head>
<!--[if IE]><script src="excanvas.js"></script><![endif]-->
</head>
The difference between Canvas and SVG is explained as follows:
SVG and canvas aren't really
interchangeable technologies. SVG is a
type of retained mode graphics where
everything is drawn from a rather
abstract model (the SVG document).
Canvas on the other hand is a kind of
immediate mode graphics, where there
is no model and the client
(JavaScript) must take care of
redrawing, animations etc.
The answer depends on what you need:
if you need to add event handlers to the graphic objects: you need to use SVG. Else Canvas.
if no events are needed is performance important: if yes then Canvas 5.
Note that IE 9 supports Canvas and offers more HTML 5 support compare to other browsers!
I've seen a few JavaScript image rotators that use either the HTML5 canvas element or an AJAX call to a server-side script, but is it possible to do it without using those methods? Internet Explorer doesn't support canvas (I'm aware of excanvas, but I'd like to do without if possible) and I'm not sure if AJAX will be fluid enough. If there is a way, are there any open source scripts, examples, or resources that you could point me to?
Alas, CSS does not support rotating images in any way, shape or form (unless you count CSS Transforms, which are only supported by Safari 4 and Firefox 3.1).
Your best bet is to use Raphael's image() and rotate(), which should support all semi-modern browsers (using SVG) and most versions of IE (using VML).
This jQuery plugin works in major browsers including IE: http://wilq32.googlepages.com/wilq32.rollimage222 . It makes use of excanvas, but at least it allows you to evaluate if that method is good enough for your purposes.
Yes, via CSS Transform:
var degree=180;
document.getElementById('image_name').style.transform='rotate('+degree+'deg)';
Google is your friend:
http://www.walterzorn.com/rotate_img/rotate_img.htm
But the downside of this technique (as mentioned) is that it uses hacks by inserting a huge number of DIVS so it could slow down the browser a good bit. Use with caution. Problems like this are why the canvas tag was created in the first place.