move images around in a google-like map - javascript

Before posting this question I did many tries and searched everywhere for alternatives, but I gave up and I'm asking here..
What is the easiest way to create an interactive map controlled by functions?
Here are details:
I have a div with fixed width/height, without a background, and I need to dynamically add things (images/text) inside of it, at any position, and they can also overlap each other if needed.
An example is better than thousand words:
- assuming the div is 500w 500h, I need to create an image at (200,200) with a size of 50x50
Here are the thousand words:
I tried with canvas, but it's too hard to remove something without touching the other things (for example if images #1 and #2 are overlapped and I want to delete the #1, I'll delete part of img #2 in the process. Of course the best thing would be to save things stored to when I need to delete something I can redraw all the rest, but it's a huge pain, if something easier exist would be better)
Tried also with http://leafletjs.com/index.html, but it seems too powerful to solve my problem, and I don't even know if it works without a background.
Maybe the best solution would be to use simple divs with good positioning, so I can change through functions their content easily, but I suck at div positioning.
Thank you to everyone that can help me :)

I really recommend the MapBox JavaScript API. It's a nifty utility that I have used in various instances. https://www.mapbox.com/blog/mapbox-javascript-api/ Extremely extendable API.

Related

Disable/enable webGL Context in webGL/three.js

I have a cool project with three.js, and everything work as intended. It displays some mesh in different canvas, and there is my issue.
The project aimed to display many, many canvas, and each one have his own context, and it reach the deadly limit of 16 live webGL contexts. Since it's wanted to display more than that in a page, I'm searching to turn around this restriction, by disabling a context when it's not actually displayed on seen page. When the user will scroll, context will be disabled/enabled so I can put as many context as I want.
I've found this function : renderer.forceContextLoss() and with this one I can force the context disabling. But I didn't found anything to relaunch it. I manage to detect a loss of context, but not its restauration
If you got any idea of how I can achieve that, feel free to give me some tips.
Thanks in advance !
This has been covered elsewhere but the easiest way to make it appear like there are multiple canvases is to just use one instance of three.js, make it cover the entire window, put place holder divs where you want to draw things, and then use element.getClientBoundingRect to set the scissor and viewport for each scene you want to draw in each element
There's an example here.
Here's the answer in StackOverflow from which that sample originates
https://stackoverflow.com/a/30633132/128511
This will use far less memory than using multiple canvases, each of which would need it's own data, it's own shaders, etc...

JS Good way to make marking effect with line

There is an effect of pointing to a special element of image with line.
See example of crocodile at http://snapsvg.io/.
When the image appears at first there is no any pointing with lines:
Then after scrolling appears lines with hints:
I know there is https://github.com/julianlloyd/scrollReveal.js and a lot of other js libraries for effect of appearing.
The question is how to make this lines, place them at the exact point on top of usual image (not SVG) and animate lines on scrolling?
Would be great to know the name of this approach/effect (what to google) and see reviews on good/bad experience, or js libraries.
Update: want to see resolved issue with image resizing and exact pointing,
In most cases, see example at http://www.sitmed.com.br/produto?id=2, image has fixed isze and is not scalable, this will not work for big or small screens.
I think it is possible to write scaling library in javascript, using svg/canvas or even plain div.
Otherewise points will jump on image scaling.
To make these lines and place them at exact position:
The easiest is to use canvas or svg. Here are a few links to do that.
Drawing lines on html page
Drawing arrows on an HTML page to visualize semantic links between textual spans
Placing the lines is easy if you're using canvas. If you are using images for lines, you can place these lines with respect to the big crocodile. Not a big deal.
Animate lines on scrolling
A good place to start with knowing about animations is to learn any animation framework. I would suggest Greensock Animation Platform(GSAP). It is open source and also well supported. They have good tutorials and docs for beginners. You can animate in a very abstract manner using GSAP. Rapheal.js is also good for animating svg images.
As for as scrolling is concerned, you can find many plugins including the one which is mentioned in the question.
Just use a parallax scrolling type js library such as Skrollr. It's very easy to just make the lines a div with a background color, and then as you scroll the page the div grows in length.
The effect you are describing makes me think you are looking for something like flow or organization chart "connectors" which anchor arrows in a chart to glue points on each element. In more general graphics terminology these are likely just known as "line anchor points" or something similar.
JointJS is a great charting/drawing library for HTML5 and SVG that could make what you are doing fairly easy to do, but a simpler "CSS only" might be all you need. If you are you really looking to animate the image then the more sophisticated javascript library approach might be worthwhile. JointJS uses Raphael and Backbone.js so you get a lot of power tools in the box.
You can use this library for drawing SVG lines, its quite configurable and well documented. You basically need to specify your "From" and "To" elements and a line will connect them for you.
Then you can play with the line's stroke-dasharray and stroke-dashoffset properties on scroll to achieve effect of the line being drawn.
More of SVG animation here
I have used this approach and its quite cool looking, hope this helps
I think the best way to implement this depends greatly on what animation you're going for. To reproduce something similar as in your example, you could just stack different images (one for the crocodile and one for each component). Then as you scroll, you could change the z-index of the crocodile and use css animation to "wobble" the size of the element you just revealed. Put all of the images in one div together, to make sure they scale together and align nicely and you're done.
But for something else the work might be completely different of surprisingly similar, I really don't think there's one solution that fits all needs, except if you want to use the canvas as already suggested, but that depends on the complexity of the graphics you want to reveal.

Web Design: Client wants a rotation-based navigation bar

I don't know if this is possible, but the client is adamant. He wants his navigation bar contents to be aligned along a "Fibonacci Spiral".
This thing:
I don't even think the CSS3 rotation aspect is functional in any browser currently, and I have no clue if any of the scripting languages would allow me even the faintest of possibilities to create a custom, curving track to force objects to follow instead of the standard (and pretty much only) horizontal and vertical alignment methods. However, I truly do embrace a good challenge. Backing down without an effort is hardly doing a good job.
If any of you know any possibility even of the greatest magnitude in how I might achieve this effect, I would be amazed. THank you for your time! If you think this is truly impossible to achieve in a current web browser, say so!
Interesting idea anyways. Hope you can make your client happy.
I thought i might chip in with something.
Found a jQuery-plugin that bends text along a curve:
http://tympanus.net/Development/Arctext/
Perhaps one could make a layout of square divs of diminishing size and specify a curve for each one?
Possible div-layout if you turn it around: http://upload.wikimedia.org/wikipedia/commons/9/95/FibonacciBlocks.svg
The plugin specifies the curving from a radius-value and can curve upwards or downwards. It does not seem to be constructed for tilted curves, but that can perhaps be modified.
EDIT: I experimented a bit with the plugin, and i believe it certainly is possible to achieve the effect you need, albeit one does have to know trigonometry quite well (as far as i can tell) to make it function properly.
Another option, and the easiest way i can think of so far, is to make use of an old classic: Image map!
http://en.wikipedia.org/wiki/Image_map
Just photoshop a nice spiral image however you like and use image mapping to set linkable areas. This can maybe be of interest: http://www.outsharked.com/imagemapster/default.aspx?demos.html

Drawing a grid in javascript ( game of life, for example )

Essentially, I had this idea in my head for a sort of evolution simulator, not exactly like Conways Game of Life, but the one part where they do match is that they will both be based on a square grid.
Now, personally, I like working in HTML+Javascript+ for simple apps, since it allows fast UI creation, and if you're not doing something computationally heavy, then JS in a browser is a decent platform.
The problem I'm trying to solve right now involves drawing and updating the grid. I might be missing something, but it seems like there is no easy AND computationally light way of doing this for an 80x40 grid. The easy way would be to generate a div with absolute position and a specific background color for any square that is NOT empty. However that can become very slow with anything more than 60-70 colored squares.
I'm definitely willing to switch to a different language if the situation calls for it, but first I just want to know I'm not stupidly missing out on an easy way to do this with HTML+JS.
Answer should include either one of the following:
a) A reasonable way to draw and update a 80x40 grid ( where the squares change color and "move" ) in HTML+JS
b) Another language that can do this reasonably fast. I would prefer to avoid having to spend a few days learning DirectDraw or something of the sort.
Why not build the grid as an HTML Table? After all this is what you want?
Give each cell a computed id and create some javascript functions to update them. Shoudlnt be a problem at all.
You could look at the new canvas tag in HTML 5 but from what you've said I dont think you need it.
<canvas> seems to be the right way to do this. A library like Raphael will help you avoid cross-platform issues. Another options is Processing.js, but it does not work in IE.
For a small grid (< 100x100), use a table and give each cell an ID for fast access.
For bigger grids, you should consider using a canvas object or embedding an Java or Flash applet.

Arranging elements on the screen and saving their positions

I want to build a tool (with HTML5, JS and CSS3), which helps customers to arrange elements on a website mockup (e.g. text blocks and pictures). I want to save the position of these
elements in order to reconstruct the whole mockup website later.
Maybe a grid system would be the best?
alt text http://img.skitch.com/20090817-t4p54kbxw3rj58mkmqxspj4qch.png
I would be happy to get some ideas on approaches for this challenge. Are there any similar projects, I should take a look at?
Regards,
Stefan
YUI has lots of widgets for this sorta thing with lots of examples.
Drag & Drop: Examples
Especially this example
Drag & Drop: Using Interaction Groups
All you would have to do register a listener on the drop event to send an ajax request to the server and save the xy co-ordinates.
ALSO, if you want to do resizing as well
Resize Utility: Examples
They have a few really neat examples, including this image cropper
ImageCropper Control: Real Time Crop Feedback
The jQuery framework would help you in synchronizing the JS and DHTML events. As far as other projects that use this, I'm not aware of any, but a grid model seems like a good way to go. Just make sure it's more precise than the 125px you currently have :)
EDIT: The website that was mentioned in the DHTML book I mentioned in my comment was http://www.panic.com . You can take a look at their JavaScript code for some inspiration, as they implement a drag and drop system for downloading their products.
Not sure if it'll help, but my "PanelManager" might make things a little easier (if you're not already using a larger framework with similar functionality):
DP_PanelManager
"Panels" are just normal DOM elements with extensions for common actions/modifications (moving, resizing, etc). Panels can exist within one or more "PanelManagers" which allow you to treat them as a single unit (sorting, looping, etc).
Look at the example "Drag-and-Drop with Ordering" for a simplified example of (what I think) you're looking for. You would then need to do the same kind of looping to save whatever information you want (probably just name and position).
In any case there might be some code there you can rip out - feel free to fold, spindle and/or mutilate.

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