I was wondering if it's possible to create an image of a div inside a page in php, jquery or javascript? Or even just a screenshot of the entire page (on my own server - not external)..
What I want to do is create an image of a graph (drawn in via jQuery) and pass it onto a PDF, as I can't seem to get the jQuery to display in the pdf..
Because of the security risks, it is not possible to get Javascript to make a screenshot of a web page. This would allow you to steal credit card info, etc... You can use an active X control or something like that, but the client has to knowingly install it in order for things to work.
In PHP, you can create an image and place it on a web page, but again, you cannot see what is on the client's screen. It has to be done on the server before it is sent to the client.
Here is an example of a library you can use to draw a graph in PHP. http://www.aditus.nu/jpgraph/
You might be able to mimic what jQuery is doing in your script but it will take a shift in your applications design.
Take a look at this article:
http://www.developerfusion.com/code/181/capture-screenshot/
It's not client-side code, but you mentioned PHP so maybe server-side code is an option. I don't think you can do it client-side...
How about using a server side graph generator, for example for PHP? Maybe the transition hurts but you'd get a really stable and simple solution.
If you describe what kind of charts you exactly generate and what server side options you have, I'm sure you'll get some specific hints.
Your best bet is to use the GD library on the server to generate the graph as needed. There's no practical way to screencap the browser canvas. Check out this PHP graphing library, it may be what you're looking for:
http://graphpite.sourceforge.net/
If you run into problems where you're doing processing on the client-side that don't exist on the server (i.e.: summing up rows or taking in user settings from cookies), maybe you need to consider passing that data back to the server and letting your hosting handle it (after all, that's why you run a server with lots of RAM and a big CPU, to crunch numbers).
If your javascript draws the graph on a canvas, you can serialize the canvas and then send it to the server using POST.
I don't know if jquery can draw the graph on a canvas, but if the graph is a simple one you could probably code it yourself as canvas has drawing tools already.
Obviously, this only works with browsers supporting canvas.
Related
I'm looking for quite a specific technique.
The short of it:
I need HTML which can generate a line chart, as shown below (but without the background image. That is totally irrelevant)
However, I want to make it in HTML, without Javascript or Flash and in a way that the dots can be hovered to show more information.
The long of it:
The image shown above comes from the website jpgraph.net. That is a PHP library for creating charts. The downside of that however, is that it generates images. Since you have no clue of knowing where the dots are going to end up, you can't estimate where the hovers should be made.
Ofcourse there are also loads of javascript ways of doing this, but the graph should also work without javascript.
Flash is out of the question, since it should also work on tablets (read iPads)... And because it is flash...
All the information shown in the graph is generated by an external system. That means that the code should work and change the graph, depending on the information put in there.
EDIT:
I'm aware of the fact that it is easily done with javascript, and my fallback would be to offer a javascript version and as a fallback the php version. However, I'm hoping to find a way which doesn't need a fallback. Using 1 script to do the same task would be better than using two.
You should check out Charts.js by Nick Downie.
It has simple HTML5 Charts using the canvas element -
Charts and Graphs Included:
Bar Chart
Doughnut Chart
Line Graph
Pie Chart
Polar-area Chart
Radar Chart
Read the documentation here: http://www.chartjs.org/docs/
and download on GitHub here: https://github.com/nnnick/Chart.js
Hope I Helped
For those still interested: I fixed this using the jpgraph.net library. It's a php library which allows you to draw graphs on the server using data you get from somewhere else.
As enhzflep pointed out, since you have the data, you can calculate where the points will end up. This is however, quite a tedious job, but it's working in javascript-less browsers.
I am just stuck a little in making a choice between PHP chart Lib and JavaScript Chart Lib. I do understand that PHP if for the server side and Javascript for the client side. My problem is what difference does it make when using their charting libraries. Is it performance issue or what?
I want to understand the difference in using PHP chart Libs and JavaScript Chart Libs. Please am not looking for examples of their chart libraries. I am looking for why i should choose one over the other.
I tried to google 'php chart vs javascript chart' but didn't get any links that can give me
the difference.
EDIT 1
1)
If this question has been answered before, then point me there.
2)
Am developing the application for internet
EDIT 2
1)
I have found out about PHPChart PHPChart which has both PHP source code and JavaScript source code. If anyone has experience in that library, does it may be solve the problem of server side load (bandwidth issues) etc.. I am thinking since it has both the PHP and JavaScript source then it may be the best to use. Am just assuming. :-)
Thank you very much
Both ways of creating graphs have their own pros and cons.
If you decide to do it using PHP, first you need to make sure that you have all the required graphical libraries installed (e.g. GD, which might not always available on shared hosts).
Assuming you have them, the first negative thing in my opinion is that you will end up with static images. Of course, it's not always a bad thing, as that ensures compatibility with all the clients, be those with or without javascript support, however, it takes away the dynamics of graphs generated on the client side using javascript. Your users won't be able to zoom, move, slide, full screen or do anything that they could with the likes of Highcharts or Flot.
Another con is that images take up more bandwidth than, say, JSON. The bigger you want to have your graph, the more colors it contains, the longer your clients will have to wait till your page loads. And just because those loads are not asynchronous, they will have to wait for the images to load before they will see the rest of the page.
With javscript libraries everything is different though. You only request the data required for your graph and you only request it when your page loads. The amount of data is usually smaller than an image would be plus you can compress your output with GZ to make it even smaller. Users will see nice spinners informing them that the graph is loading instead of some incomplete webpage.
Another thing to take into account is - what if you decide to show a nice table with data in them below each graph? If you chose to render images on the server, you would end up having to add new functionality just to get the data. With JSON, however, you just make one call, render the graph and display the table. Maybe calculate totals or do whatever you want with it. Hand it out to people as an API if you wish, after all :)
If you ask me, I would definitely go with client-side graphs as most of the devices have nice HTML5 support nowadays and being able to display a graph on an Android phone, or an iPhone or an iPad shouldn't pose a problem. If you only need images and you don't wish to expose the original data, go with PHP.
My opinion is that having a server side solution (i.e. php) takes away any browser compatibility issues you may have with a client side solution (i.e. javascript) and hence support issues.
A benfit of using JS is that it does offload resources from your server to the client because you may only have to generate some light weight data (e.g. JSON , XML) and the rendering occurs on the client. You will have to investigate how many hits your server is likely to get, etc to determine if resource is an isuse with PHP or JS.
However, using Php to create images of charts you can always get around the performance/resource issue by using a cache of the image files and serving from the cache (it's a just a folder of images) instead of generating a new one. Whether you cna use a cache will depend on your usage. If clients require up to the second data and its always changing, obviously a cache may not be of use.
Here's what I see :
Using PHP
Increase load on the server for the request
Will work everywhere
Also, like someone said here and made me think of it, you can cache the image that PHP give you, reducing bandwith (no lib to download) and reducing load (cache)
Using Javascript
Decrease load but increase the bandwitch and addition http request (to load the JS lib)
Will work where JS is available
But remember, PHP take more load then an HTTP request.
Also, always remember, Javascript is made for effects and specials stuffs you need to display.
There is one PHP render advantage that no one told about. Since sometime you need to include chart as image into PDF, DOC, XLS etc. file or email it – you have no other way except to render chart on server and store it as image to be inserted.
For data manipulation you use PHP.
For visual and behavioral effects you use JavaScript.
For that reason, you should use Javascript as its designed for visual behavior. Plus it will put less load on your server as all processing will be client side. As more people use your application simultaneously, it will start to slow down as your server will be doing a lot more then it has to.
Hope that helps :)
I am trying to develop a website in which you can scribble on an element and want to share it to all who is seeing the page using ajax. A miniature version of whiteboard. I have know Idea where to start. I have decent understanding of Html, CSS, Javascript(Jquery)and PHP. I am having a starting trouble. No idea what all technologies and methods to use.
You should create an HTML5 canvas element and position it above the element. On the canvas you can implement a simple scribbling functionality (such as the one here).
When you want to sync the scribbling to the server you can use the Canvas's toDataURL method to post the image data to the server using ajax.
On the server you can decode the base64 encoded dataurl and distribute the image as a regular image to the other viewers.
try to implement a single-user wihteboard with canvas. thats a method to draw something on websites, not limited to vector-graphics.
if you're done with this try to communicate with a central server via ajax and upload the canvas' data. then it's possible to distribute your new content to as amany other clients as you wish. and if they modifie it, reupload the new data.
as an alternative for canvas you may want to try a svg approach. this could bring some benefits as the data you will have to send over the internet is smaller, but ie is like always...
I have a question. I have to prepare a good report module for an application in PHP and MySQL. The report should be in two forms: a graph and a normal table with text. Tables and text are simple, but the graph is what I don't know how to begin. I was thinking about HTML5 (canvas) and Javascript, but honestly I don't know if this is a good idea.
I don't know if HTML5 is rendered on all browsers in the same way. A while ago it was a problem and I didn't have time to investigate it by myself. Good tips about new elements (canvas, article, footer and so on) on different browsers (including mobile ones) would be nice.
Maybe someone had similar problem and can give a tip on how to begin?
There are lots of free javascript tools for that, for example:
jqplot
Google charts
Google charts uses canvas for canvas capable browsers and flash for other browsers (like IE).
One thing you might consider is using wkhtmltopdf to generate a PDF of whatever HTML5 you want, using the consistent Webkit rendering engine. I'd set it up like this:
The user clicks a link that says "generate"
This loads a script which runs the report (generates the data, etc.) and outputs the HTML needed to a temporary file
Invoke wkhtmltopdf using the temporary HTML file as input and output it to a temporary PDF
Read the PDF into PHP, set the headers, and output the PDF to the browser
This should create a fairly seamless experience and shouldn't take more than a few seconds to run, and since it's Webkit, you can use whatever Javascript library you want to make charts (I like flot).
Depends on your target user group. If you wan't to hit the maximum ammount of web browsers you should probably go for a flash based graph solution. Flash however is not supported on iPad and iPhone.
If you want to support iPhone/iPad and still have an interactive graph, go with Canvas - however i don't belive it's supported by Internet Explorer yet.
I'm working on a biology web based application and trying to figure out what language to use. The features I need to include are:
Image viewing frame - This area will display the current image that the biologists wish to see. The application needs to take in a number of coordinates from a file and draw those points on the image displayed here. When the biologist wishes to change images there needs to be no flickering from the refresh. Will do this using multiple image buffers probably. Content needs to be scrollable and able to be zoomed in.
There need to be labeled buttons that advance, step back, zoom, and play the images displaying in the image frame. There also needs to be some type of list view where images titles can be selected to be displayed.
There will be a bunch of folders of images on the server that can be selected from. The application must allow the user to select which folder of images to be loaded. It also must be able to read from either an txt or xml file and visually display the information there by way of line graph.
Would like to be able to run scripts on the server from the application.
I feel that all these things are doable by a web application but I have no idea what language to use. Most people recommend php, but i don't want to delve deeper until I know what its limitations are. Any suggestions are welcome. Thanks in advance.
-Mike
PHP can do everything you need for the back end, but most of the stuff that you describe is UI based, and this is dependent on the client, which is, of course, the browser. For highly graphical projects, you can do a lot in JavaScript and some JavaScript libraries have a lot of these capabilities built in. You might also consider Flash or Flex.
You might even consider a desktop application that runs outside of the browser. You can use Java, which is easy to deploy, but still requires the user to have the Java Runtime Engine, or you could go with a language that you can compile down to a native application.
Regardless of the front end technology that you choose, you'll still need a back end, and PHP can handle this.
You will find almost every server side platforms such as php , asp.net, asp, etc will do all of the above.
PHP is a language that resides on the server and handles all requests. Javascript (and associated libraries) is a language which is executed by the client's browser and handles (almost) all interaction. PHP is definitely able to do what you want, but for the interaction stuff (particularly the zoom, scrolling, etc.), you'll also need to use Javascript.
So, short answer, PHP is good, but you're going to need to use client-side scripting as well.
PHP is more than capable of doing this. You are going to need to use it in combination with some Javascript to handle the client side effects you describe. I would look into modifying galerific for your needs and then whip up some javascript to write points over the images.
From your concerns about image refresh/flicker, it really sounds like a desktop app is what you are looking for, for a rapid response on image changes. The requirements on this really seem to need to be defined better before you can choose a language... PHP can do all the server side stuff you mentioned, but you might have a harder time getting the image viewing "frame" to provide the functionality you want.
Due to the image manipulation requirements it might be easier to go with something like flash with a php backend or asp.net with silverlight. It might be difficult to prevent flicker and delays with using pure javascript as opposed to flash/silverlight.
Image viewing frame
This will most likely need to be done on the client side using tools/frameworks such as jQuery, the canvas element, silverlight, or any of the other 100's that are out there.
There need to be labeled buttons that advance, step back, zoom, and play the images displaying in the image frame. There also needs to be some type of list view where images titles can be selected to be displayed.
PHP or any other server-side scripting language could pull this off. If this is meant to be a quick project running on free/cheap hardware then PHP would be a good choice. If the plan is a large application that will have to be maintained over the course of many years and hosting/price is not an issue then I would suggest something like ASP.NET
There will be a bunch of folders of images on the server that can be selected from. The application must allow the user to select which folder of images to be loaded. It also must be able to read from either an txt or xml file and visually display the information there by way of line graph.
Again any server side language could do the folder listing portion. As for reading files and creating graphs, this would most likely be a combination of server side and client side programming. jQuery for example, has plugins that could quite easily take a xml file and create a line graph.
Would like to be able to run scripts on the server from the application.
PHP, ASP.NET - both could do this. I'm sure many others could, but these are the ones i use most often
The issue with PHP is that quite often, the code turns into a mess over time. This is maybe not so much an issue with the language as the people using it and the purpose the app was built for (a quick, one time project). Classic ASP also has the same issues.
ASP.NET is a good combination of OOP programming that allows you to separate presentation from logic with minimal effort.