Unity Resizing Dropdown Dynamically - unity3d

Question

I have a dropdown list on a filter panel which needs to stretch dynamically to fit the content as shown:
I have tried several content size fitters but cannot find anything, If possible I would like to set a max width it can expand to then truncate everything longer than that, I would also like it to expand only to the right with a right pivot point. I have found a similar example here: https://forum.unity3d.com/threads/resize-standard-dropdown-to-fit-content-width.400502/
Thanks!

Answer 1

Well. Lets start with the code from that Unity forum thread.
var widest = 0f;
foreach (var item in _inputMines.GetComponentsInChildren<Text>()) {
widest = Mathf.Max(item.preferredWidth, widest);
}
_inputMines.GetComponent<LayoutElement>().preferredWidth = widest + 40;
We want to have a max-width allowed, so any content longer than this will be truncated. So let's add that variable:
var maxWidth = 250f;
//or whatever value; you may wish this to be a property so you can edit it in the inspector
var widest = 0f;
foreach (var item in _inputMines.GetComponentsInChildren<Text>()) {
Now we use the smaller of the two width values. Then apply it to the content layout:
}
widest = Mathf.Min(maxWidth, widest);
_inputMines.GetComponent<LayoutElement>().preferredWidth = widest + 40;
The +40 should be retained because that deals with the scrollbar. Your maxWidth value should be chosen to account for this.
Finally we want the longer items to get cut off nicely.
Give each dropdown item a Rect Mask 2D component (Component -> UI -> Rect Mask 2D). The template object exists in the scene hierarchy before the game is run, just disabled. You can just add the component to the parent transform, the one with the image (so the text is clipped).
You'll need to make sure that the mask covers the same width as the image graphic and expands along with it, possibly slightly shorter on the X direction so the text gets cut off before the image border is drawn. This should happen automatically, but you will need to check and possibly make some alterations to the template object. Alternatively you can use an Image Mask, but you'll have to play with that one yourself, but it will allow for non-rectangular clipping.
That's it!