I have a number of UI elements like panels, edit fields, buttons, labels etc. so panels contain other panels which contain input fields, editors and so on. Most of the elements are editable and/or resizable which means whenever I change anything, a lot of adjacent UI elements should change their width, height and x/y position on the pane. It works fine with a small number of elements but incredibly slow when the number of elements is thousands. Is there a fast layout algorithm which can be used in this case? Note that I cannot use any existing layout managers and should come up with my own implementation.
1 Answers
I'd suggest taking a leaf out of the Android playbook and have a larger 'grid' and keep everything sized in modular multiples - this avoids you needing to solve the knapsack problem everytime!
For example, instead of having a button with an width of 80 and a height of 40 you store this as metadata as {2:1} (assuming your layout grid is 40^40 squares).
This way if you have a work panel with space of, say, {2:12} this could be filled with two objects of size {2:6} or maybe 3 of size {2:4}.
It's pretty simple to fit-to-max too as any available space can just be scaled up (say you delete a {1:1} item you can just expand the one next to it to take the space etc - you can of course create your own rules around whether objects can scale in single directions etc.
The other advantage of this approach is that you can easily manage different screen sizes and resolutions too while still keeping the same framework and look and feel.
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