I have a project about chinese chess.
First I have to create a board and about 32 chessman on board .
Should I using 1 canvas to create board then draw 32 images on it OR create 1 board canvas then create 32 canvas , each for 1 chessman . Because I want to drag and drop chessmans but it seem not well when I have to redraw too much if just use 1 canvas. What should I do , can u give me some advices or give me some same tutorial . Thanks!
KineticJS is a Javascript library that will help you out. It supports dragging of things on canvases, etc. Here's a simple tutorial using Kinetic and an HTML5 canvas: http://www.html5canvastutorials.com/kineticjs/html5-canvas-drag-and-drop-tutorial/
This might be a matter of preference, so take it with a grain of salt. I would only use one canvas and draw the pieces directly onto it.
In most games (HTML 5 included), the rendering is all pretty "smoke and mirrors", and the real data is stored in ugly structures behind the scenes. Trying to use multiple canvases pulls some of that data (specifically location) and mess into the rendering layer. While this can probably still work, you'll have more control over whats happening if you keep all the data behind the scenes, and use math to determine where to render and whether or not a mouse click has hit an object and you need to start dragging.
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I'm brand new to Flash Professional and wanted to make a short 10 second clip. Instead of looking into using tweens and symbols (I wish I did) I used Flash Professional as a flip book, illustrating sketches for each keyframe.
I'm now in the colouring process and want to know if there is a way to colour an object (I've drawn with the brush tool) throughout multiple frames. is this even possible?
I understand there are some short cuts to repetitive tasks using ActionScript. But, once again I am brand new to Flash Professional and haven't tried anything in the ActionScript. I do however have a very basic knowledge of HTML coding and some javaScript if it helps at all…
If there is an alternate solution like exporting the file to another Adobe program that has a "colouring multiple frames" feature, that would be great too.
Sorry to say, to do that, you WILL have to work with symbols. However, this is an easy fix.
Select the object you want to color, click Modify--> Convert to Symbol. Give it a good name, and set it to MovieClip. Click OK.
Now, in the Library panel, double-click the icon next to your symbol name. Color as you wish.
There are multiple ways to put this on your timeline. You could replace each instance of that drawing with the symbol. Or, better, you could create a new layer with only one keyframe (and regular frames after that to the end of your animation. Place your object on that layer, and then remove all the old versions of that drawing.
NOTE: You will need to be mindful of where in the stack you put layers, as that sets the z-index of everything on that layer.
I am using Pygame 1.9.2a with Python 2.7 for designing an experiment and have been so far using Pygame only on a need basis and am not familiar with all Pygame classes or concepts (Sprites, for instance, I have no idea about).
I am required to draw many (45 - 50 at one time) shapes on the screen at different locations to create a crowded display. The shapes vary from displaced Ts , displaced Ls to line intersections. [ Like _| or † or ‡ etc.]! I'm sorry that I am not able to post an image of this because I apparently do not have a reputation of 10, which is necessary to post images.
I also need these shapes in 8 different orientations. I was initially contemplating generating point lists and using these to draw lines. But, for a single shape, I will need four points and I need 50 of these shapes. Again, I'm not sure how to rotate these once drawn. Can I use the Pygame Transform or something? I think they can be used, say on Rects. Or will I have to generate points for the different orientations too, so that when drawn, they come out looking rotated, that is, in the desired orientation?
The alternative I was thinking of was to generate images for the shapes in GIMP or some software like that. But, for any screen, I will have to load around 50 images. Will I have to use Pygame Image and make 50 calls for something like this? Or is there an easier way to handle multiple images?
Also, which method would be a bigger hit to performance? Since, it is an experiment, I am worried about timing precision too. I don't know if there is a different way to generate shapes in Pygame. Please help me decide which of these two (or a different method) is better to use for my purposes.
Thank you!
It is easer to use pygame.draw.rect() or pygame.draw.polygon() (because you don't need to know how to use GIMP or InkScape :) ) but you have to draw it on another pygame.Surface() (to get bitmap) and than you can rotate it, add alpha (to make transparet) and than you can put it on screen.
You can create function to generate images (using Surface()) with all shapes in different orientations at program start. If you will need better looking images you can change function to load images created in GIMP.
Try every method on your own - this is the best method to check which one is good for you.
By the way: you can save generated images pygame.image.save() and then load it. You can have all elements on one image and use part of image Surface.get_clip()
In my web application I want the user to be able to draw some rectangles on an image, also change the size of the rectangles and drag and drop them. after that I have to get coordinates of rectangles and send them to server's database
Is it better to create a canvas on a photo or load the image in canvas ?
I don't write any code yet because I have no idea how to do this.
Any ideas,suggestions,links,libraries ?
As the comment said canvas is a good bet for this, but you'd need to do a fair bit of coding to get it working.
I actually have a tutorial on making Canvas interactive by drawing rectangles and moving them around. It should give you a good start on this project.
There are also a few libraries, such as fabricJS, but that might be hard to get the coordinates out of without digging into the library.
I am trying to generate some sun 'rays' which I can best describe as looking like the blade of a krisknife, such as the blade portion of this picture.
This is just an example. I only need a triangular shape with two or three waves that I can close and fill.
Better yet, is there some HTML5 app with which I can draw a complex figure and then export the javascript (moveTo, arcTo, bezierCurveTo, quadraticCurveTo, ...). Something similar to HTML5 Bezier Sketcher but which saves the javascript. Trying to draw complex figures blind is very difficult and I don't want to switch to SVG if it is not necessary.
Thanks 1,000,000
Edit: I have now also looked at all the options at this site. None will allow me to draw and fill simple curves and then see/save canvs commands. All that show commands show them in new libraries like fabric or jsDraw2D.
You can parse SVG into an html5 canvas with fabric.js.
That might do the trick for you.
https://github.com/kangax/fabric.js
Beside SVG it can help you with a nice API to canvas drawing.
I found the answer among the solutions for Convert SVG to Canvas friendly output. The author didn't think it worked for him, but I think it's as perfect as any I have seen.
Professor Cloud (...is frikkin' amazing! This isn't the first thing he's done I have found incredibly useful.) created a site to take SVG input and product Canvas output. You can see it here, at Professor Cloud SVG-to-Canvas.
Using this site, I can draw something or even take a stock vector image in AI, export as SVG, cut out the commands and past them into Prof. Clouds amazing SVG-chipper, and get Canvas code. I understand it doesn't support full SVG capabilities, but then, neither does Canvas. Great for me.
Your solution is probably best but just for the record, I tried experimenting with some graph plotting, and got some nice results:
The equations are:
sin(x)*log(2/x) + x/10
sin(x)*log(2/x) - x/10
You can plot them using: http://www.graphsketch.com/
It looks good with 0 < x < 25
I am a junior developer I can't understand how canvas tag is beneficial for us?
I read lot of articles on that but I can't get the root benefit getting from the canvas tag.
Think of the difference between canvas and svg as the difference betwee Photoshop and Illustrator (or Gimp and Inkscape for you OSS folks). One deals with bitmaps and the other vector art.
With canvas, since you are drawing in bitmap, you can smudge, blur, burn, dodge your images easily. But since it's bitmap you can't easily draw a line and then decide to reposition the line. You need to delete the old line and then draw a new line.
With svg, since you are drawing vectors, you can easily move, scale, rotate, reposition, flip your drawings. But since it's vectors you can't easily blur the edges according to line thickness or seamlessly meld a red circle into a blue square. You need to simulate blurring by drawing intermediate polygons between objects.
Sometimes their use case overlaps. Like a lot of people use canvas to do simple line drawings and keep track of the objects as data structures in javascript. But really, they both serve different purposes. If you try to implement general purpose vector drawing in pure javascript on top of canvas I doubt you'd be faster than using svg which is most likely implemented in C.
Basically, thanks to canvas, we can now draw/render 2D shapes using HTML5 and the canvas API.
As an example of what's possible now with canvas, see this
Some possible uses for Canvas:
Image drawing program
Photo editing/manipulation
2D Games
Advanced image viewing such as Microsoft's Deep Zoom
If you can't understand how it's beneficial, then maybe it isn't from your point of view at least. Don't think that because it's there I have to use it somehow, pick and choose what technologies work for you based on what you're trying to build, an Accounting web app probably wouldn't need a canvas for instance.
The canvas will enable you to draw pixel perfect graphics.
The cool projects that came to mind for me are:
Visualize gps data. GPS data is just an XML list of coordinates. You could easily build something in canvas to "connect the dots".
An mobile app where the user can actual sign a document with her finger - canvas allows you to export out the rendered canvas drawing to PNG where it can be saved on the server.
In a game where you have avatars, you can allow the user to actual draw on the avatar. Moustaches anyone?
Other stuff:
In iOS / Android using lots of CSS3
effects like box-shadow can lead to
poor performance, especially when
animating. You can do a lot of these
graphics in a single canvas tag,
here's an example:
http://everytimezone.com/. This thing is flawless on an ipad.
Cool background effects. For example try going to Paul Irish's
site and move your cursor around the
background: http://paulirish.com/
In this HTML5 book sponsored by Google a lot of the effects are using
canvas:
http://www.20thingsilearned.com/ -
particularly the "page flip"
animations.
my personal take on canvas (and when I actually found a use case for canvas) is the ability to color pick and color change per pixel in a canvas element - actually moving the image from something we don't have any information about what is happening inside it to an element like all other DOM elements (and yes, I know about the current problems with canvas and DOM - sure this would be taken care of in the future)
sure - canvas made some sort of animation easier and pluginless, but that we could do before (mostly with flash) - I think the real importance is the ability to know what is happening on the page.