Starting with an arbitrary rectangle, a user can place any number of circles within.
The circles are allowed to overlap each other without restrictions.
The circles can be of different sizes.
What would be the best way to test if the rectangle is completely covered by the circles?
It seems a very tricky algorithm, but fortunately dsomebody thought about it before :)
Check this question:
https://cs.stackexchange.com/questions/11163/circles-covering-a-rectangular-how-to-verify-it
Seems to have the same problem as you.
I eventually found that the simplest solution (for me anyway) in both JS and Objective-C was to simply iterate of over each pixel and check for the colour (assuming circles are coloured) and check if it was the colour of a circle (or it's border). As soon as a colour from a circle was found then iteration stops as the area is obviously not fully covered by the shapes.
The advantage to this solution is that the actual shape doesn't matter (we ended up adding other shapes also).
Related
The question is very simple. I just want to draw a simple circle around some part of an image with mouse. Not a fancy circle. It can be not at all a complete circle. I just want to circle around some part of an image to make it stand out inside the image.
As simple as this task is, I did not find any solution on google as it always proposes me very complex tasks like how to draw a circle and the like, which are not at all what I want. The problem is that Gimp is very powerful and so non-intuitive for very simple use cases. Any help will be appreciated as it will free me of doing all these changes under windows on another computer and sending the images via email and etc.
Quickest:
Make a circle selection with the Ellipse select tool (you can constrain it to a circle by depressing the Shift key after you start dragging).
Edit > Stroke selection (use preferably "Line" mode, that will also allow you to make a dotted line).
This said, to annotate images there are better alternatives.
basically I am trying to edit not only the appearance of the button(thats the easy part) but the frame that detects the touch to be a rhombus rather then a square
html example:http://irwinproject.com
I've tried CGAfflineTransform however it doesn't allow me to make non rectangular objects. is there a way to skew
Im just wondering if this is possible because, if not could someone point me in a direction the only viable answer I've found is resorting to something along the lines of a spriteKit;
I found this however this implementation leaves dead spots on buttons where they overlap
custom UIButton with skewed area in iPhone
is there a way to message people on here there was a gentleman who said he figured out how to transform but never posted his solution.
In order to modify the touch area of an oddly shaped button you could use a solution similar to OBShapedButton. I have used this particular project in the past myself for adjacent hexagon buttons and it worked perfectly. That said, you may have to modify it a bit to work with drawn shapes instead of images.
I am working with kinect in openframework using the ofxKinect addon, which is great and plenty fun!
Anyway I am looking for some pointers or a direction when dealing with multiple bodies on the screen. I was thinking of making a rect around each detected body and when the rects intersect something could happen, an effect or anything.
So what I am looking for are ideas or something that could point me to the right direction of detecting multiple bodies when using a kinect.
Right now based on the depth image I get from the kinect I go through each pixel and create a bunch of smaller rectangles with a padding and group them in a larger rectangle bound if they are separate from another rectangle group. This is not ideal as it only deals with the pixel values and is not really seperating bodies from eachother and is not giving me the results I am looking for.
So any ideas would be greatly appreciated!
If you want to use ofxKinect a quick solution would be to threshold on depth and assume bodies and no other objects will be within a depth range. This should make it easy to use the OpenCV's contour finder to isolate the outlines of the bodies and get the bounding rectangles. If the rectangles intersect(and ofRectangle already does the math you), trigger the reaction you need. Also don't forget to do that once if the effect isn't showing already, otherwise you will trigger the effect multiple times per second while the two bodies' bounding rectangles intersect.
You could try something a bit more hardcore and using ofxCv(not just ofxOpenCV) to tap into the HoG functionality. This is slow in itself and not ideal with the depth map, but hopefully you can run in every few seconds just to detect a person and the depth, then keep tracking that movement.
Personally, if you want to track people with the Kinect I recommend using ofxOpenNI as if already provides the scene segmentation feature and even if you don't track the skeletons you can still get useful information like the pixels pertaining to each body and they're centre of mass. I'm guessing Microsoft KinectSDK has a similar feature and there should be an oF addon, but it's windows only.
ofxKinect/libfreenect does not offer any people detection features, so you will need to roll your own.
Let's say I have a solid, irregularly shaped (but enclosed) shape on screen in iOS (one colour). I then want to "erase" portions of that shape by dragging my finger around like you would in a typical kids colouring app, erasing with a fixed brush size where I touch the screen.
I could easily accomplish all this with something like an image mask and touch detection however, as a requirement, I also need to determine the rough percentage of the shape that remains.
For example I need to know when 50% of the random enclosed shape has been "erased".
What's the best way of approaching this problem? Are there any existing iOS compatible libraries that can handle it? I'm thinking that I would need to keep track of a ton of polygons and calculate all the overlaps but it seems like there must be a solution to this problem.
EDIT: I have done research into this problem however tracking all the polygons manually and calculating all their positions and area overlaps seems overly complicated. I was simply wondering if anyone else has run into a similar issue and found a better solution.
you will need to first know the fixed space of the image view. then you will need to know the percentage of blank space when the new image is loaded. pixel
double percentageFilledIn = ((double)nonBlankPixelCount/totalpixels);
After you get that value you will need to use that percentage as your baseline for the existing percentage
your new calculation will look like this.
double percentageOfImageLeft = ((double)nonBlankPixelCount/totalpixels/percentageFilledIn);
this calculation will likely be processor intensive. I would only calculate sparingly.
Since this post is not about code and more about login I will let you determine your logic for detecting non blank pixels.
here is how to find a pixel color.
How to get Coordinates and PixelColor of TouchPoint in iOS/ObjectiveC
Good luck.
I have a layer with a sprite of a simple black donut. I want the user to be able to draw on the sprite in a different color (which I've managed to do without any problem using CCRenderTexture).
My question is how I can calculate whether the image has been traced at least 95% (meaning, find out when 95% of the black pixels are now the new color). I've tried methods like taking a screenshot of the layer and counting the number of black pixels, but it hasn't worked that well (using this solution: https://stackoverflow.com/a/1262893/1577738).
It would be even better if I could just change the color of each pixel as it's touched (to avoid issues with coloring out of the lines). I could theoretically just split the donut into like 10 sprites and change that section's color if the user touches it, but that seems ridiculous if I give the user options to use a bunch of different colors.
Am I going about this the wrong way? Your suggestions are much appreciated!
Reading pixel colors will be rather inaccurate and slow. I suggest dividing the area into smaller rectangles (ie 8x8 or 4x4) and then flag each as "visited" when the user draws on it. If most rectangle areas are flagged, the user has drawn on most parts of the texture.