I created an animation (curve animation) in flutter and I reuse the values provided by this animation. According to my console, I can have 35 values.
Is it possible to have more values generated, like ~60?
Thanks
No. This value depends purely on the framerate and the animation length.
There's no "limited number of values" like your question is implying. A new value will be generated whenever needed, which is usually once per frame.
Related
I'm am trying to make it so that when you interact with a slider, it goes up or down by 5. I know you can make it go up in whole numbers but can you change the base value that it increases/decreases by?
Not a built-in feature unfortunately. The workaround is to enable Whole Numbers, and set:
Slider min = Actual min / Step
Slider max = Actual max / Step
Then in your code you can do Actual value = Slider value * Step
Or you can write your own slider component with stepping support.
PS: I know, it sucks.
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.
I'm making an app which allows the user to apply GPUImage filters to still photos using a UISlider. I'd like for the slider to initially start at the zero point for each filter (i.e. the value at which none of the filter has been applied yet) and I'm wondering how this can be determined? I've used some of the values that are listed in the GPUImage documentation and for certain sliders they start at 0, but others it's hard to determine (and for some, the min and max values are way off for me). The values for something like GPUImagePosterizeFilter seem to be way off for me (set min to 1, max to 128 and initial to 1). I've also checked some of the values in the FilterShowcase test project which are different than the documentation, but still don't always start at 0. Am I just completely missing the point here? Or is there some setting I maybe have to turn on to be in line with the slider values?
Nope, no setting for this. All I can really recommend is that to make this as efficient as possible make a switch statement in a single method and determine what to do by index of the currently selected filter.
From there, I would leave the min/max values of the slider the same so that you don't have to animate from one calculated point to another if the filter changes and mathematically convert the slider's value into units that the current filter understands. i.e. 0-1 --> 1-128
I think I might have been approaching this the wrong way. Rather than looking for a "zero point" on a filter, I think I should focus on applying the filter only when the user applies it, and trying to find a good starting point that is close to how the image looks without the filter for the initial value on the slider.
I'm using FlowCoverView, an open source (and AppStore compliant) alternative to Apple's cover flow (you can find it here http://chaosinmotion.com/flowcover.m)
How can I change the tile (or texture as it's called in the library) size (statically at least)?
The code comes with a statically fixed 256x256 tile size. This is fixed using the TEXTURESIZE define and hard coding the number 256 within the code.
I tried to replace all 256 occurrence with the TEXTURESIZE define and it works... As long as the define is set to 256! As soon as I put another value, I get white 256x256 images in the flow view (I pass the correctly dimensioned UIImages through the delegate of course) :(
I can't find where in the code this 256 value is used. I repeat: all 256 occurrences were replaced by the TEXTURESIZE constant.
PS
Of course, the next step to improve this nice library will be to make the TEXTURESIZE a property, to be set at runtime...
Use this. It is much easier to implement then yours.
https://github.com/lucascorrea/iCarousel
Change the TEXTURESIZE to 512 . clean the build and run it
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