I am currently working on an app, which includes a paint function. It actually doesn't work that bad, but the problem is, that the refresh-rate or the frequency of the calls for the touchesMoved-method is too bad.
If you move the fingers fast over the screen, the lines get many edges and it doesn't look that good. So i thought about increasing the call-frequency for this method. Would that be a good and even possible solution for my problem?
Maybe you can help me with my problem. Thank you in advance.
Think about this approach: Look at Adobe's Ideas App on the AppStore. If touchesEnd, work with NSBezierPath to get a smoother look without edges. You basically store the points in touchesMoved in an array? So you got the points to insert in the Bezier Path functions. You have a edgy look while drawing but after releasing it looks kind of smooth. I did so in one of my projects and result is fairly okay.
(But there are many other approaches to build a drawing application.)
Demo App from Apple: Click here
Related
I need access to the coordinates of individual strokes of a PKDrawing in PencilKit. Is there any way I can get access to that? Currently, my only idea is to try and decode the opaque data representation we get from PKDrawing.
As Ben has said, there doesn't seem to be any way to access stroke-level data in PencilKit at this time. This seems like a pretty rudimentary feature so hopefully Apple will add it next WWDC. Fingers crossed.
LetsBuildThatApp's YouTube tutorial is a good starting point if you just want basic drawing capabilities and are not too concerned about drawing quality or latency. I ran into issues when I tried to add the ability to vary the stroke width with pen pressure. I was never able to get it to transition smoothly between stroke segments of different widths - it always 'jumped' jarringly from one width to the next. Maybe there's a way to fix that, but I wasn't able to.
I suspect that currently, the only way to draw low-latency high-quality images with Apple Pencil is to write a drawing engine from scratch in Metal or OpenCL. It's strange it has taken Apple so long since the release of Apple Pencil to get a comprehensive drawing framework out. Fingers crossed that changes at WWDC 2020.
Edit: Apple announced substantial updates to PencilKit at WWDC20, including access to stroke data and functions to programatically draw strokes.
I was was looking for the same thing and from this comment https://stackoverflow.com/a/57565661/8891611 and my own searching of the documentation, it seems what you're asking for doesn't exist. If you do discover a way to decode the opaque data please update this thread on how so.
If you aren't necessarily set on PencilKit, you could manually code your drawing functions which is easier than it sounds. In this tutorial: https://youtu.be/E2NTCmEsdSE?t=504 I have timestamped where he shows that he has access to all the points on the lines he is creating.
And another potential solution could be to use both, by have a mapping between your PencilKit drawing and the points found from the technique in this tutorial.
For the strokes, you can access the property .renderBounds that gives you the dimensions of the rectangle where the stroke is into.
See the picture below. It's a flash game from a well known website :)
http://imageshack.us/photo/my-images/837/poolu.jpg/
I'd like to capture the images, frame by frame, using Matlab, and then lenghten the line that goes from the 8 ball, the short one, so i can see exactly where it will go. And display another window, in which the exact pool table will appear but with longer lines for the paths :)
I know, or can easily find out, how to capture the screen and whatnot, the problem is that i'm not sure how to start detecting those lines, to see the direction they are heading towards. Can anyone suggest an idea on how to accomplish this? Any image processing techniques i could use to at least filter out everything except those lines.
Not sure where to even start looking, or for WHAT.
And yeah, it's a cheat i know. But i got programming skills, why not put them in practice? :D Help me out people, it's a fun project :)
Thanks.
I would try using the Hough transform in the Matlab Image Processing Toolbox.
EDIT1:
Basically the Hough transform is a technique for detecting linear structures (lines) in an image.
I have to implement long exposure photo capabilities to an app. Since i know that this is not really possible i have to fake it. It should work like "Slow Shutter" or "Magic Shutter".
Sadly i got no clue how to achieve this. I know how to take images with the camera (through AVFoundation) but i'm stuck at merging them to fake long shutter times.
Possibly i need to manipulate and combine all the images with coregraphics but i'm not sure about this (even the how). Maybe there's a better solution to this.
I would appreciate every help i can get here,
thank you people!
You might try the plus lighter blend mode.
Well, I suppose it would be possible to average together the results of several shots. I've mucked around a bit with the core graphics stuff to resize images (averaging together adjacent pixels), but with lower res images. The algorithm I used is here -- maybe it'll give you some ideas.
There may, of course, be a better way, and some tricks for working efficiently with high-res images. Can't help you there.
Convert the images to pixel bitmaps. Align and stack the bitmaps. Then try applying various 3D convolution filters to the 3D pixel array.
I'm new to IOS development, and want to create something with tiles similar to what you see here. http://www.youtube.com/watch?v=i7giaN5T7ww
Since I'm a beginner, I see myself placing a bunch of buttons on the screen and labeling them to how I see fit. Then figuring out how to move multiple "buttons" at once. I was wondering how you think the tiles are created in this program? If not done by a bunch of buttons, could someone show me code to draw a tile with dimensions of 48x48 pixels, then place a letter on the tile?
Also, if you could point me to some helpful resources that would help me develop something along the lines of a project like this, I would most appreciate it. I'm excited and very motivated to learn and master IOS development and consequently objective-c.
My knowledge is limited to what I've learned by watching and coding along to these two YouTube playlists:
http://www.youtube.com/user/thenewboston#p/c/640F44F1C97BA581
http://www.youtube.com/user/thenewboston#p/c/53038489615793F7
They've been extremely helpful in helping me understand the basics of Objective-C and Iphone development. Unfortunately, it didn't get into drawing and manipulating objects on the screen.
Thanks in advance for your help. I've found this site and its users quite helpful already. :)
I have kind of similar apps in the app store and I used in one case UILabels and in another case UIViews with UIImageViews as subviews. The movement of the labels I have implemented with the methods touchesBegan:withEvent, touchesMoved:withEvent and touchesEnded:withEvent.
I am new in iphone and as well in cocos2d
I have some queries about a game i am working on it.
Actually i have a background with some trees and bushes.and i have an object which keeps on moving and my background of trees and bushes is static at the back. I want the application to repeat the background and it give me a look that my object is moving forward.
Can anybody Guide me please.
I also want to implement speed so also guide me that how can i change the speed of background repetition. so that it gives a look that my object is slow or fast
Thanks
waiting for your positive response.
Regards
sHaH
Work through this excellent tutorial:
http://www.raywenderlich.com/3857/how-to-create-dynamic-textures-with-ccrendertexture
It'll surely help you.
The section "Repeating Backgrounds" explains how to make a texture repeat and animate it.
In order to change the speed you can make PIXELS_PER_SECOND a dynamic variable.