What's the secret to make a custom FWT component (ie: Canvas) fill 100% of the parent width ... somehow this is giving me trouble.

I'm guessing I have to override prefSize() ... but don't know what to return for 1005 width.

Or maybe let m,e explain my actual issue

If I do:

Window
{
  size = Size(800,600)
  EdgePane
  {
    left = Label{text = "Hello"}
    right = Label{text = "Bye Bye"}
  },
}.open

I get what I expect ("Hello" on far left "Bye Bye" on far right)

Now If i use an "expandable" grid

Window
{
  size = Size(800,600)
  GridPane
  {
    numCols = 1
    expandCol = 0

    EdgePane
    {
      left = Label{text = "Hello"}
      right = Label{text = "Bye Bye"}
    },
    // maybe some other items
  },
}.open

They get bunched next to each other on the left. I though expandCol would make the grid 100% width .. i guess not.

What to do to get the expected result ?

I though expandCol would make the grid 100%

No, it's weird; expandCol means, which column to expand to take excess space.

If you've got numCols set to 1, then set expandCol to 0 and it should then grow. (the examples/fwt/demo.fan demo is handy to tinker around with).

You also want halignCells to fill; expandCol makes the cell grow but leaves the item in it (the EdgePane) at default size; halignCells=fill makes the cell content grow to fit the cell.

Doh! Thanks, can't believe I missed that for a while.

Argh!

content = GridPane {
  ...
  halignCells = Halign.fill
  ...
}

Thank you!

I've been meddling with layouts for days trying to figure that one out!