Let's say I have curved path made using a serie of bezierCurveTo() calls. I'd like to make it appear progressively in an animation, by increasing the percentage of it that is drawn frame-after-frame. The problem is that I cannot find a standard way to draw only a part of a canvas path - would someon know of a good way (or even a tricky way) to achieve this?
Sure...and Simon Porritt did all the hard math for us!
jsBezier is a small lib with a function: pointAlongCurveFrom(curve, location, distance) that will let you incrementally plot each point along your Bezier curve.
jsBezier is available on GitHub: https://github.com/sporritt/jsBezier
Just found a small library that does exactly that: https://github.com/camoconnell/lazy-line-painter
It relies on the Raphael lib (http://raphaeljs.com/), and the two put together do not make too big a payload.
Related
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()
After Effect has the possibility to apply the a Bezier Surface over an image.
However we want to achieve that affect with AS3.
We can use DisplacementMapFilter, using a mapBitmap for each frame for the bezier effect..
How can we generate each of those bitmaps?
The only information that after effect gives are the 12 control points for 12 key frames each one.
How can we with that information generate those mapBitmap that the DisplacementMapFilter operation requests?
Maybe after effect has another information that we are missing?
Thanks in advance.
I'm asuming you're trying to come up with something like this: http://fatlinesofcode.philipandrews.org/2011/02/20/warping-bitmaps-with-a-bezier-surface/
Displacement map filter has limitations that would make this difficult.
The trick is to break up the image into triangles and warp these triangles along the bezier lines/surface you like. The more triangles you use the smoother the resulting image.
this is a good place to start : http://www.flashandmath.com/advanced/p10triangles/index.html
here is a more advanced example (without code) http://www.miaumiau.cat/2010/03/simple-surface-editor/ that is using bezier curves
more code here also: http://wonderfl.net/c/rFOlY
you can try looking up more resources with drawTriangles and distort keywords
What the best way to make this kind of transformation: I have 4 pairs of coordinates, and I need to put the corners of my image exactly to them?
Like in photoshop, when you in free transform mode and moving corners of the image while holding ctrl.
Something like that.
If you can use the Flash 10 drawTriangles() method, then this link will provide you with a great explanation of what you are trying to do, with some well documented functioning code. The code is very similar to the solution that romamik provided, however, you will need to calculate the correct t value of the uvtData to get it to render correctly:
To summarize from that link:
Calculate the center point of the rectangle you are trying to draw
Get the distance between each point and the center
Calculate the ratio between the diagonals
use the formula (1/point_distance)*ratio to calculate perspective distortion for each point -- project into a faux 3d space (aka "magic" as the author of the post calls it)
That should produce the effect you are looking for.
If you can't use drawTriangles() then this link provides an alternative, however it wont produce as good of results as the drawTriangles() method.
You can use graphics.drawTriangles.
http://help.adobe.com/en_US/as3/dev/WS84753F1C-5ABE-40b1-A2E4-07D7349976C4.html
This code should do what you need (untested)
graphics.beginBitmapFill(bitmapData);
graphics.drawTriangles(
Vector.<Number>([10,10, 100,10, 10,100, 100,100]),
Vector.<int>([0,1,2, 1,3,2]),
Vector.<Number>([0,0, 1,0, 0,1, 1,1])
);
You can use the DistortImage class ported from the old 3D engine Sandy. A cleaner way would be the make use of rotateX and rotateY but it would require some mathematical pain!
I'm trying to animate a nodal with flash for teaching purposes. This is what I want to animate:
My questions:
How can I move the line through a guide?
Can guides hold z positions, so I could make the rope's top and bottom parts more real?
Can a vector image (rope) move through a guide path?
Which way is this possible, strokes or brushes?
Does as3 scripting support "decorated brush" effects?
Is there a simpler way to do this such as sandy or awake3d or beziercurves?
If you're using the IDE like CS4 or CS5 there are some menu options to do this. I only use a text editor and Flex SDK to compile. While I know what you're talking about, I can't really answer this one since I don't have the program. There's plenty of tutorials on the subject, however.
I believe the path-following tools in CS* only follow (x,y) coordinates. No Z values in the menus, but you can code them yourself. Again, I don't have the program, but from the tutorials I read it looks like no.
I suppose it could. Instead of a line drawing like you have here, you could simply use an image of one rope segment (as in a picture of rope whose length is equal to one twist of the rope), then apply transformations to get the correct 3D perspective.
Basic flash programs only draw fills. You can, however, run a shader program (called pixel bender) within flash which will draw strokes for you.
Not on it's own, no. But there is nothing stopping you from programming your own decorated brush class.
Bezier curves are probably the way to go.
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