How to superpose two GwtCanvas? - javascript

I'm trying to superpose two GwtCanvas (which use an Html5 canvas). I am able to get this effect by using an absolute panel. But by doing this, I can't get my object to fill my panel. I would like to this so I can do a whiteboard in GWT. So far, I'm pretty advance but I would like to have multiple canvas overlay to support undo or preview. For example, if we draw a rectangle, it would be good to preview it as we move the mouse. I have found a javascript tutorial to do this :
ex:
http://dev.opera.com/articles/view/html5-canvas-painting/
There is a javascript example, but I'm not sure how to do the bridge between GWT and JavaScript. Any ideas ?

I think you should go for GWT JSNI - This way you would be able to access your JS from GWT code. You can find more information about JSNI at the following location:
http://code.google.com/webtoolkit/doc/latest/DevGuideCodingBasicsJSNI.html

Related

Javascript Flow Chart or Static Flow Chart?

Let's say that we have the following image:
I'm thinking of drawing this image with all the possible connections and then position some labels on their correspondent arrow... but this may not be the best approach, because the position of each label would be different depending on screen resolution. What do you think about this approach?
My question is: anyone knows any JavaScript library, jQuery plugin capable of drawing something like the image above? I mean, capable of doing multiple connections and that could be implemented with AngularJS ?
Here are some new details:
After I make some tests with JointJS, I think it is what I need, but...
the following link is an example of JointJS with a demo of connections/links between sources and targets that I would have on this project... The thing is: as you can see on this demo has alot of links and it's hard to interpret. Can anyone help me on how to make this look better? There's a better way of representing this? (on this example the link's are static but they would be done on a dynamically way).
You can check out below urls:
JSPlumb provides a means for a developer to visually connect elements on their web page
http://jsplumbtoolkit.com/demo/flowchart/jquery.html
http://jsplumbtoolkit.com/demo/home/jquery.html
Wirekit looks good for creating custom wired flows:
http://neyric.github.com/wireit/
JointJS is a modern HTML 5 JavaScript library for visualization and interaction with diagrams and graphs.
http://www.jointjs.com/
Here is a nice angular library
https://github.com/codecapers/AngularJS-FlowChart
and an example of it in action
https://dl.dropboxusercontent.com/u/16408368/WebUI_FlowChart/index.html

Creating a complex interactive wheel as a web app

How would you do to create a chart like this, interactive (i.e. with links and tooltips), in an HTML page?
From what I know about SVG I think it's the right direction to take (no Flash anyway), but I'd like to know what would be the path you'd take first in order to have an interactive chart looking like this on a web page.
I'm not asking for the details but just where to begin to look. I know JavaScript quite well, but I have never dealt with any SVG libraries.
checkout d3.js examples, this example looks very close to your pic.
I offer to use Raphael library (http://raphaeljs.com/) and if you like to make more complex or using 3d objects you can use webgl with treejs library (http://threejs.org/) .. you can find example and demo for charts or other documents in websites..

framework to create tooltip (createjs and kineticjs)

I'm searching for a JS framework that is compatible with CreateJS and KineticJS to create tooltips on a canvas.
I'm making an app that uses both CreateJSs and KineticJS and I want to draw tooltips on both of them (without using two libraries).
Thank you.
There are dozens (if not hundreds) of tooltip scripts out there—just ask google!
I assume that since you want to support both createJS and kineticJS that you must have already coded the trigger that requests a tooltip.
With that in mind, here is one tooltip library: http://www.opentip.org/documentation.html
It’s open-source so you can use/modify it freely.
It’s controlled by javascript so you have createJS/kineticJS independence while still working in JS.
It uses html canvas to display the tip so customizations should be familiar to you.
The tip-canvas is temporary and it floats so it should not interfere with your main canvas.
It allows you to offset the tooltip, so your code can exactly position the tip as you need.

How to use your pointer as a writing pen in a page?

I want to find a way to make possible to draw on the entire browser page or a part of it using the mouse pointer. It will be just a blue line that it will be created when the button is clicked.
Is there any technology instead of Flash?
Thank you
Take a look at this. It was the first result on Google when searching for JavaScript Painting. It's a step-by-step guide on how to use the JavaScript canvas to create a drawing tool.
http://dev.opera.com/articles/view/html5-canvas-painting/

Drawing arbitary pictures on a webpage

I need to display a runtime-generated image (mostly consisting of nice-looking boxes, lines and text) on a webpage. We're currently using ASP.NET MVC3.
The problem is, I haven't really done web development before, and I have no idea how to go about drawing an arbitary diagram on a webpage. Do I use some sort of javascript? How, and what do I use? Do I generate the image on the server somehow and simply display it? Something else?
I have no idea where to even start, let alone solve the actual problem...
It depends on the target browser.
If you target the most modern browsers, you can use an HTML5 Canvas and draw on it using JavaScript (see http://www.williammalone.com/articles/create-html5-canvas-javascript-drawing-app/).
If you're targeting other browsers (as well), the easiest is probably to generate an image on the server side (GIF/JPG/PNG). Your HTML page then contains an IMG tag with the SRC parameter set to the page that generates and returns the image. You can find an example at this page: http://www.sitepoint.com/generating-asp-net-images-fly/ (this uses ASP.NET to generate the image).
Roy Dictus fairly well described the overall approach you'll want to take. If you decide to target modern browsers and use javascript, I'd suggest you look at Processing.js. It's a javascript port of a popular Java library, and the web page has some code samples to show how you can create both static drawings and animations with some simple code.

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