How to calculate or technique UIBezierPath control point smooth shape.
Each control point has to move. But its shape remains as it is.
i tried but it is not smooth
I dont know where I can get a complete algorithm or examples? Please help me out
Thank you.
ex.
Example Image
What you want is basic knowledge of bezier curves. First of all smoothness depends on whether it is a quadratic curve or cubic curve. Smoothness increases as number of control points increases.
Basic description of cubic bezier curve.
And this link will help you to control points.
Calculating control points.
I don't remember exactly from school right now, but when u want transition smooth you have to make 2 points of bezier curves same for smooth transition.
Related
I am trying to understand how manim automatically figures out how to smoothly transform, say, a Circle() into Square()?
Is this a common pattern? Is Manim unique in this respect or are there similar libraries which do the same magic? I am interested in figuring out how to create manim animations for iOS without running python.
I'm not going to explain all the math behind it, just an outline so you can learn on your own.
In Manim, every curve that you generate (circles, squares, etc.) is a Bezier Curve, these curves have very special properties and are widely used in multimedia and graphic design software.
The transformations are essentially interpolations between Bezier curves, that is, if you want to transform a circle into a square, what Manim does is take those Bezier curves and interpolate between them using an algorithm.
Learn here Bezier curves.
I took time looking for ways to make a simple graph, only about showing a line that goes from one point to another point and curves along the way that will be the benchmarks, I've only found a way to make complex graphs with straight lines, would appreciate any reference or support, thanks
I leave a picture of what I want
http://i.stack.imgur.com/5DCRr.png
Quartz2D(Core Graphic Framework) is suggested.
You can draw straight line, rectangle, circle, ellipse, curve(of a circle), or Bezier curve.
I am creating sort of a 'paint' application in which use can draw free curves. If i draw the sampled points as is, the curve does not look smooth.
I tried the algorithm in the following tutorial: http://www.merowing.info/2012/04/drawing-smooth-lines-with-cocos2d-ios-inspired-by-paper/#.U2e1EK2Sy-Q
This tutorial create smooth curves using quad bezier curves.
The result is OK, but still not as good as i would like and i can still see the curve 'breaks'. How can i improve the curves and make them smoother, similar to 'paper' application?
I will draw a curve similar to the red curve in the illustration below (can be a bezier or whatever is most convenient for my purposes I think). I would like to find points on the curve (blue dots in the illo). The points would most likely be divisions of equal parts of the length of the curve.
Can I find these points? I am not seeing a solution in the docs as of yet.
This answer covers segmentation of a Bezier curve using the de Casteljau algorithm. You already have your parameterized values along the curve for segmentation.
(If you follow the link referenced in the answer make sure you have java enabled in your browser, so you can view the example visualisations).
I'm using OpenCV on the iPhone. I want to find a Sudoku in a photo.
I started with some Gaussian Blur, Adaptive Threshold, Inverting the image and Dilate.
Then I did some findContour and drawContour to isolate the Sudoku grid.
Then I've used the Hough Transform to find lines and what I need to do now is find the corners of the grid. The Sudoku photo may be taken in an angle so I need to find the corners so I can crop and warp the image correctly.
This is how two different photos may look. One is pretty straight and one in an angle:
Probabilistic Hough
http://img96.imageshack.us/i/skrmavbild20110424kl101.png/
http://img846.imageshack.us/i/skrmavbild20110424kl101.png/
(Standard Hough comes in a comment. I can't post more than two links)
So, what would be the best approach to find those corners? And which of the two transform is easiest to use?
Best Regards
Linus
Why not use OpenCV's corner detection? Take a look at cvCornerHarris().
Alternatively, take a look at cvGoodFeaturesToTrack(). It's the Swiss Army Knife of feature detection and can be configured to use the Harris corner detector (among others).
I suggest the following approach. First, find all intersections of lines. It is helpful to sepparate lines into "horisontal" and "vertical" by angle (i.e. find two major directions of lines). Then find the convex hull of acquired points. Now you have corners and some points on the boundaries. You can remove the latter by analysing the angle between neighbour points in the convex hull. Corners will have the angle about 90 degrees and points on the boundaries - about 180 degrees.