I´m doing some testing on gradients using NSBezierPath and make some progress so far with radial gradients. see first picture. I wonder, however, if it is possible to make angle gradients as in picture 2.
Anyone done this?
Tia, Ronald
Cocoa has no public API for angular gradients. You'll have to do it yourself by painting pixels in varying colors.
Good Question!
There is no Standard Feature.
Try to approx by dividing the Circle into sectors which functions as clipping Polygon
Then draw a linear Gradient in direction 90 degrees to the Center line of the sectors.
Related
I just added a sprite-circle to a 2D-Game with physics. I just realized that the circle has only very few vertices. Can I increase the vertex count of the circle by using GUI only?
I am using the LTS 2020.3.29f1 version of Unity
A sprite does not have vertices, it has pixels.
You can use a higher resolution texture if you wish to make the sprite look better when scaled up.
If your concern is accuracy of the collider's hitbox, then you can't do better than the CircleCollider2D as it has effectively infinite resolution in respect to a perfect circle.
I seem to be missing something related to how Affine Transform works in PDF. I have a requirement to do below -
A shape whose bottom-left edge located in origin
Rotate the shape to 90 deg Counter-Clockwise
Translate the shape to the destination
Now, when i apply affine transform, i am not getting the proper placement of the shape in the destination. After several experiments, i found that PDF Engines apply rotation AROUND the bottom-left corner of the shape as reference, but most literature guides rotation about the center axis, suggesting no difference would occur doing either way.
But i am not able to get correct arithmetic behind my transform ad i am unable to achieve the result. I am not very sound in Mathematics, hence, would appreciate any help in achieving this.
Prepare some illustrations to show how i am doing the transform.
My understanding of the math behind the transform may be wrong altogether and would appreciate if i can get some guidance. I am using PDFBox to achieve the same. Thanks in advance.
Im making a simple 3d game where Ive got some boats colliding and changing directions to avoid eachother.
Part of the collision handling is built around bouncing and then diverting the heading direction slightly (boat A hit boat B, A bounces back then rotates say 10 degrees to the left and resumes movement)
So far, Ive just updated the heading direction, which looks a bit abrupt. I intend to interpolate from the old heading to the new one. It is very simple, the heading is always just an angle around one axis. So basically its going from say 90 degs to 110 degs.
Im aware of quaternions and slerp, which would give me a constant velocity (my rotation should be silky smooth). But I just end up feeling like its using a sledge hammer to kill a fly. What is really the consequence of just doing a regular vanilla linear interpolation from 90 to 110 for the rotation angle? Will it even be visually noticeable that I have used quaternions instead of the much simpler and much cheaper linear interpolation of angle values? I have no special important "key frames" that need to be hit - there is no "animational data" at all, the 3d models are static.
So if someone could shed some light of what potential problems I could run into if I just interpolate the rotation degrees instead of using slerp, it would be much appreciated.
Thanks
/Jim
I have a problem with detection of chessboard-like pattern. The image is very noisy because it is registered with the use of laser scanner.
The only thing I have managed to achieve is detection of big rectangle:
Now I have no idea how to detect those small squares. I tried all sorts of different algorithms, but the contrast in the squares seems too low. Does anybody have any ideas?
Other pattern images: https://dl.dropboxusercontent.com/u/3681534/kalibrator/6.png https://dl.dropboxusercontent.com/u/3681534/kalibrator/8.png
A way to progress would be to determine the grayvalue level at the inner border of the rectangle, then:
Adjust the average brightness inside the rectangle border.
With that knowledge it is possible to adjust the average brightness inside the rectangle to one value (the small square will still be a bit lighter than the rest)
Increase the contrast a lot
Find the lines that run along the edges of the squares
Either access the line crossings directly or paint white and black
Calculate your calibration data
Is it possible to get this kind of gradient in cocoa ?
I can use simple CGContextDrawRadialGradient with clip made by CGContextAddEllipseInRect but the effect will slightly different.
Is it any posibility to draw exact this shade/gradient?
I would use a radial gradient, and then apply a scale trasnformation such that the y coordinate is squiched, and the x remains.
There is an advanced topic where you can define your own gradients providing an callback that calculates the color or so. Ist stated in Core Graphics docu.