Example
Video Example
The lack of selection styling in paperjs makes you improvise and one way to style them, is to create them yourself ( recommended on this post).
But the huge con with this is the performance! Where canvas quickly goes from usable 60fps to terrible 20 within seconds. Now the only method I thought would work to style your handles/points, is now useless.
Now I'm out of ideas as to how style them and I'm trying to seek the help of stackoverflow... The main thing that I want to achieve is the hover effect on handles/points . At this point I coded the most of the stuff in paperjs, and I really wouldn't want to switch everything to something else like PixiJs.
P.S Any help is appreciated!
In your video, the frame rate goes down because you draw a lot of paths and this would also happen at some point even with the native Paper.js selection.
So your only chance is to try to have as few as possible shapes in your scene.
Maybe you can take advantage of the less known features of Paper.js to reduce them a bit:
item.selectedColor
paper.settings.handleSize
Then, there is also the possibility of using SymbolItem for repeted shapes (like your circles) that should have better performances than regular paths.
Finally, if you're out of solutions, you could also fork the library and hook into the selection drawing code to adapt to your needs :).
Related
I am looking to animate an image onto a canvas via a circle 'brush' [Think Photoshop default brush] wherever the circle moves on a path the image is revealed.
The image would be a bitmap, not a vector file.
The brush will not have any additional detail beyond displaying the image its 'painting'
As additional clarification, the circle brush is moving automatically the user does not move the brush. It is just animated along a path.
I am really curious to see how this can be done with Raphael.
Thanks in advance!
If you want to achieve something like that, you better think of using Canvas. Since Raphael is a library oriented exclusively to SVG. You can use non-svg images, but you are going to face lots of limitations.
On the other hand, Canvas is pixel oriented, so what you are trying to do is going to be easier.
Raphael is great when it comes to SVG and user interaction, because the elements you create, are nodes inside the DOM, and you can easily bind them to events.
If you still want to achieve something like that with Raphael, you are going to need to start digging a bit into Raphael's methods. Is to difficult for someone to explain the whole process. You better start trying, and ask some question on more particular problems.
Apart from Raphael's documentation, I recommend this exaggeratedly colorful, but useful site which have some working examples.
Either way I think you should reconsider using Raphale over Canvas!
I hope that helps!!
I'd like to be able to write an application in HTML5 that is similar to the following.
HTML5 Canvas Animals on the Beach Game with KineticJS
The problem with that demo though is the mouse over event is only accurate to the rectangle surrounding the animal. Is there any way to do this with more accuracy, be it in KinectJS or otherwise?
There are generally two ways:
Using custom paths with each image as hitboxes (that you manually define) then using an is-point-in-path algorithm
Using a ghost-canvas (or whatever you like to call it) as I detailed in this old tutorial. Ignore the link to the new tutorial, the old one uses what you'd want.
The first method here is much faster but requires a lot more code and manual work. The second method is pixel-perfect but much slower. Still, if you don't have an enormous amount of objects it may suit your needs.
http://www.html5canvastutorials.com/webgl/html5-canvas-webgl-plane-with-three-js/
In this example its just a rotating plane.
I'm an html 5 beginner :)
However, look at how many calculation does the JS code.
I dont have any trouble with it.
but this is how its gonna be ? ( while learning html5)
for every animation I should look for the js code ? ( and try to custom it to my needs) ??
and if so , is there any centrelized place of general scripts for html 5 animations ?
Depends.
Using canvas and JS, probably. The code is just a raw drawing board, so it is subject to the same drawing code you would using in most similar scenarios. three.js (as used in that example) is used to make things easier, and having a 3d drawing context for canvas will help, but it will be pretty much the same thing as three.js (it may be even using it, I don't know. Haven't used it before).
However, that said, for simple things like that, CSS 3 3D animations will make things possible. You can modify things like perspective and rotation and get effects like that. So it depends on what you will be using it for.
If you can get away with CSS and elements, than it can be pretty easy (keyframes and CSS styles). But if you're looking for more complicated 3d effects, than yes, it will be more complicated.
1.) I found a canvas API called EaselJS, it does an amazing job of creating a display list for each elements you draw. They essentially become individually recognizable objects on the canvas (on one single canvas)
2.) Then I saw on http://simonsarris.com/ about this tutorial that can do drag and drop, it makes use of a hidden canvas concept for selection.
3.) And the third approach, a working approach, http://www.lucidchart.com/ , which is exactly what I'm trying to achieve, basically have every single shape on a different canvas, and use to position them. There's a huge amount of canvas.
The question is, what is the easiest way to achieve interactive network diagram as seen on http://www.lucidchart.com/
A side question is, is it better to get text input through positioning on canvas or using multiple canvas (one for rendering text) as in LucidChart
I'm the person who made the tutorials in 2. There's a lot going on here, so I'll try to explain a bit.
I use a hidden canvas for selection simply because it is easy to learn and will work for ANY kind of object (text, complex paths, rectangles, semi-transparent images). In the real diagramming library that I am writing, I don't do anything of the sort, instead I use a lot of math to determine selection. The hidden-canvas method is fine for less than 1000 objects, but eventually performance starts to suffer.
Lucidchart actually uses more than one canvas per object. And it doesn't just have them in memory, they are all there the DOM. This is an organizational choice on their part, a pretty weird one in my opinion. SVG might have made their work a lot easier if thats what they are going to do, as if seems they are doing a lot of footwork just to be able to emulate how SVG works a bit. There aren't too many good reasons to have so many canvases in the DOM if you can avoid it.
It seems to me that the advantage of them doing it that way is that if they have 10,000 objects, when you click, you only have to look at the one (small) canvas that is clicked for selection testing, instead of the entire canvas. So they did it to make their selection code a little shorter. I'd much rather only have one canvas in the DOM; their way seems needlessly messy. The point of canvas is to have a fast rendering surface instead of a thousand divs representing objects. But they just made a thousand canvases.
Anyway, to answer your question, the "easiest" way to achieve interactive network diagrams like lucidchart is to either use a library or use SVG (or an SVG library). Unfortunately there aren't too many yet. Getting all the functionality yourself in Canvas is hard but certainly doable, and will afford you better performance than SVG, especially if you plan on having more than 5,000 objects in your diagrams. Starting with EaselJS for now isn't too bad of an idea, though you'll probably find yourself modifying more and more of it as you get deeper into your project.
I am making one such interactive canvas diagramming library for Northwoods Software, but it won't be done for a few more months.
To answer the question that is sort-of in your title: The fastest method of doing interactiveness such as hit-testing is using math. Any high-performance canvas library with the features to support a lot of different types of objects will end up implementing functions like getNearestIntersectionPoint, getIntersectionsOnRect, pathContainsPoint, and so on.
As for your side question, it is my opinion that creating a text field on top of the canvas when a user wants to change text and then destroying it when the user is done entering text is the most intuitive-feeling way to get text input. Of course you need to make sure the field is positioned correctly over the text you are editing and that the font and font sizes are the same for a consistent feel.
Best of luck with your project. Let me know how it goes.
Using SVG (and maybe libraries as Raphael)!!
Then any element can receive mouse events.
The 2nd part of the question is, which javascript library is better/easier to manipulate images with? I won't be actually drawing any shapes or anything. Other info: I'll be using jQuery and don't need to support all browsers, just webkit.
Edit:
More information: the current design is to layout/draw several rows/columns of images in a grid-like layout, with the image in the center being in "focus" (a little larger, with a border or something and some text next to it). The tricky thing is that we want the whole canvas of images to appear to slide/glide over to bring another random image into focus. So obviously the number of images in this grid needs to exceed what is visible in the viewport so that when the transition occurs there are always images occupying the canvas. Other than moving the images around, I won't be blurring them or otherwise modifying them. Eventually we will add user interactions like clicking/touching on a visible image to bring it to focus manually.
Let me know if this is not clear or still confusing.
I ran across scripty2 which seems like an alternative to using canvas/SVG for my purposes. I also started farting around with EaselJS last night, and it seems like this might work, but I'm wondering if it'll end up being more work/complex than just using standard HTML/CSS and a tool like Scripty2 to aid with animations and click/touch events. Just looking for any suggestions. Thanks!
The answer depends on your manipulation and animation.
If it's just translations, CSS wins for speed compared to canvas. I haven't tested, but I feel confident it easily beats SVG for the same sort of thing.
If you're going to be doing non-affine transformations or otherwise messing with the images (e.g. blurring them) you clearly want Canvas.
If you need event handlers per object, you clearly want a retained-mode drawing system like SVG or HTML+CSS. I haven't done enough CSS3 transforms to say how they compare in terms of speed to SVG, but they clearly do not have the robust transformation DOM of SVG.
This is a rather subjective question (or suite of questions) and you haven't yet given sufficient information for a clear answer to be possible.