My question is two parts, and answers to either would be helpful.
I want to make a Master shape that can be expanded on one axis only. When you expand it the image inside repeats itself. I still want to be able to resize the image proportionally. See the picture for example.
Discrete extendable ladder
The second part of my question is how to restrict this expansion to discrete segments, meaning that the expanded image snaps to the next segment when it gets close enough, but nothing in between. I think I can do this with the BOUND() function, just not sure how.
Related
Let's say I have a container. I want to surround it with a border (or anything that would outline it) and be able to change it's start and end points. This would be similar to the trim paths effect in Adobe After effects. I've looked up options for container borders but the best I could find was to add it to juts one side and that is not the look I want.
The best way I can describe what I want to do is to have a border or outline to the container that looks sort of like a circular progress (but isn't round and takes the shape of the container) that has the start and end points move.
Here is a quick example I made in After Effects of what I am looking for: https://drive.google.com/file/d/1DgHZbLv_TX1D_lpfYJlL4QA0kOVbQZDe/view?usp=sharing
This needs to be done through CustomPainters. Here is a repo I came across which does this through custom painters https://github.com/divyanshub024/flutter_path_animation.
In Marks, click Size and there pops a slider where I can adjust the size of a shape. But how to accurately control the size, is there some property with numbers to accurately control it? I have two sheets to show something similar and I want to display exactly the same sized shapes.
If you want to ensure 'sizes' are the same across two worksheets, I'd suggest snapping the 'size' setting to the center on both, as this is the easiest option to select. You can then use a measure to set the size, if this is desirable, and then the difference in size will be relative on both worksheets.
There isn't a numerical value override for the size slider.
Ben is correct, there isn't yet a numerical value override for the slider. You can use parameters with Min/Max/Sum etc. and a variable to somewhat change the sizes but they have to have multiple entries per line. It is unfortunate that Tableau still doesn't get that people want both a 'relative' sizing system that uses numbers from the dataset and a 'static' sizing system that allows for shapes to be set to '11px' or something along those lines. Yes, you can control that kind of in the dashboard with a vertical and fill entire box etc; but that doesn't address the very real scenario where you want a user to be able to re-size on the fly. Just my two cents.
I ran into this today. Very annoying. Need to keep shapes the same size across all worksheets and therefore same on dashboard.
so i have looked at a couple other questions like this and from what i saw none of the answers seemed to answer my question. I created a program that creates ASCII art, which is basically a picture of text instead of colors. the way i have the program set up at the moment you have to manually set the Width and Height of the pixels. If the width and height of the pixels is too large it simply wont work. so basically what i want to do is have a function to automatically set the width and height to the size of the picture. http://www.mediafire.com/?3nb8jfb8bhj8d is the link to the program now. I looked into pixel grabber but the constructor methods all needed a range of pixels. I also have another folder for the classes, http://www.mediafire.com/?2u7qt21xhbwtp
on another note this program is incredibly inefficient, i know that it is inefficient in the grayscaleValue() method, but i dont know if there is any better way to do this. Any suggestions on this program would be awesome too. Thanks in advance! (this program was all done on eclipse)
After you read the image into your BufferedImage, you can call getWidth() and getHeight() on it to get this information dynamically. See the JavaDocs. Also, Use a constructor for GetPixelColor to create the BufferedImage once and for all. This will avoid reading the entire file from disk for each channel of each pixel.
For further code clean up, change series of if statements to a switch construct, or an index into an array, whichever is more natural. See this for an explanation of the switch construct.
One last comment: anything inside a class that logically represents the state of an object should be declared non static. If, say, you wanted to render two images side by side, you would need to create to instances if GetPixelColor, and each one should have its own height and width attributes. Since they're currently declared static, each instance would be sharing the same data, which is clearly not desireable behavior.
I need to place labels with a transparent background over a variable-content UIImage. Readability will vary significantly depending on the relationship between the color of the label's text and the color/luminosity of the area of the image displayed under the label. Since the image will be constantly changing, the color of the label's text needs to change in sync.
I have found several techniques for determining the color, perceived luminosity etc of a single pixel. However, I need to rather quickly (while a view loads) determine the rough perceived color/luminosity of an area of the UIImage under the frame of the UILabel. I presume I will also need to measure the alpha because the same color/luminosity looks different at different alpha values.
Is there a way to calculate such a value for an area? Will I be reduced to simply summing pixels? If it comes to that, is there an algorithm to accomplish this?
I've thought of two possible approaches:
Perform some "folding" operations i.e. combining pixels from one half of the area to the other half. Then repeat until I get a single value. Would this be practical? How would you logically combine pixels to average their perceived color/luminosity?
Sample a statistically significant number of pixels in the area and then combine them (somehow) to get a rough measure.
I think this problem comes up a lot these days with people being so found of customizing backgrounds. Seems like something that would be worth my time to bang out a category or class to handle this and then share it around.
What about simply outlining your text in a way that it will show on both dark and light backgrounds?
This is how it is handled in other situations where text must be displayed over a background with unknown content (for example, films with subtitles).
I am looking for an efficient way to handle the image/frame detection from touch methods. Let's say i am building a keyboard or similar to this. I have 'n' number of images placed on the UI. When someone touches an alphabet (which is an image), i can do the following to detect the corresponding letter
1) CGRectIntersectsRect(..,..) : if i use this, then i need to check each & every letter to find out what letter exists at that touch point (let's say 100,100). This becomes O(n). If i move my finger accross the screen, then i will get m points & all corresponding image detection becomes O(n*m) which is not good.
2) Other way is building a hash for each & every x,y position so that the look up will be simply O(1). But again this will be a memory constraint as i need to store 300*300 ( assuming i am using 300*300 screen size). if i reshuffle my letters, then everything needs to calculated again. So this is not good
In other words, i need some thing like , given a point (x,y), i need some way of finding which rectangle is covering that point efficiently.
Sorry for long post & any help would be grateful.
Thanks
If there are in a regular grid, then integer division by the grid size. Assuming you've a small, fixed screen size, a bucket array gives as similar gain ( a 2D grid, where each entry is a list of the rectangles which intersect that part of the grid ) is very fast if tuned correctly so the lists only have a few members. For unbounded or large spaces, KD trees can be used.
It's useful to have the rects you want as final targets set up as subviews as a larger UIView (or subclass) where you expect all these related hits to occur. For example, if you're building your own keyboard, you could add a bunch of UIButton objects as subviews and hit test those.
So, the easy and traditional way of hit testing a bunch of subviews is to simply have code triggered by someone hitting those buttons. For example, you could add the subviews as UIControl objects (which is a subclass of UIView that adds some useful methods for catching user touch events), and call addTarget:action:forControlEvents: to specify some method to be triggered when the user does something in the rect of that UIControl. For example, you can catch things like UIControlEventTouchDown or UIControlEventTouchDragEnter. You can read the complete list in the UIControl class reference.
Now, it sounds like you might be going for something even more customized. If you really want to start with a random (x,y) coordinate and know which rect it's in, you can also use the hitTest:withEvent: method of UIView. This method takes a point in a view, and finds the most detailed (lowest in the hierarchy) subview which contains that point.
If you want to use these subviews purely for hit testing and not for displaying, then you can set their background color to [UIColor clearColor], but don't hide them (i.e. set the hidden property to YES), disable user interaction with them (via the userInteractionEnabled BOOL property), or set the alpha below 0.1, since any of those things will cause the hitTest:withEvent: method to skip over that subview. But you can still use an invisible subview with this method call, as long as it meets these criteria.
Look at UIView's tag property. If your images are in UIViews or subviews of UIView, then you can set each tag and use the tag to look up in an array.
If not, then you can improve the speed by dividing your array of rectangles into sets that fit into larger rectangles. Test the outer rectangles first, then the inner rectangles. 25 rectangles would need only 10 tests worst case as 5 sets of 5.
Thanks Pete Kirkham & Tyler for your answers which are really helpful. Lets say i dont wanna use buttons as i am mainly displaying images as a small rectangles. To check for the rect # (x,y) , i can trigger that easily by making my grid as a square & finding
gridcolumn = Math.floor(pos.x / cellwidth); gridrow = Math.floor(pos.y / cellheight);
But my problem is with touchesMoved. Lets say i started # grid-1 & dragged till grid-9 (in a 3*3 matrix), in this case, i am assuming i will get 100-300 (x,y) positions, so everytime i need to run above formula to determine corresponding grid. This results in 300 calculations which might effect the performance.
So when i display an image as a rect, can i associate some id for that image? so that i can simply just save the ids in a list (from grid-1 to grid-9) so that i can avoid the above calculation.
Thanks for your help