Sheet windows: making them resizeable

From REALbasicWiki

This article applies only to Mac

[edit] Making sheet windows resizeable

Currently (RB 2008r2), the Window property Resizeable is ignored — sheet windows are shown at a fixed size and cannot be resized by the user with the mouse.

Until RB fixes this limitation, you can use the following code to make sheet windows resizeable (Code courtesy of Norman Parlardy):

Sub EnsureSheetIsResizable(extends w as Window)
  #if TargetMacOS
    soft declare function ChangeWindowAttributes lib "Carbon" (window as WindowPtr, setTheseAttributes as Uint32, clearTheseAttributes as Uint32) as Integer
    
    const kWindowResizableAttribute = &h10 // (1L << 4)
    const kWindowLiveResizeAttribute = &h10000000 // (1L << 28),
    
    if System.IsFunctionAvailable("ChangeWindowAttributes", "Carbon") then
      dim attrs as Uint32
      if w.Resizeable then attrs = attrs + kWindowResizableAttribute
      if w.LiveResize then attrs = attrs + kWindowLiveResizeAttribute
      if attrs <> 0 then
        dim result as integer = ChangeWindowAttributes(w, attrs, 0)
      end if
    end if
  #endif
End Sub

Place the code into a module. To use it, call it from within the sheet window's Open handler, e.g. with:

self.EnsureSheetIsResizable

Note: Despite setting the LiveResize attribute, the user will not get a live resizing effect when dragging the resize control at the bottom right corner of the sheet window but only a simple outline rectangle. This appears to be a limitation of RB.