At Mon, 28 Mar 2016 11:53:38 -0700, Byron Davies wrote:
> I have a single interactive pasteboard on a slideshow slide. For a learning
> task, the user needs to click on objects on the pasteboard. There’s a little
> glitch, however. The user must first click on the pasteboard to make it the
> focus, and then click on the objects. Is there a way to make the pasteboard
> become the focus when the mouse moves into it?
You should be able to use the `focus` method on the canvas after its
frame is shown (via `on-superwindow-show`) or when a mouse event is
received (via `on-event`). See below for an example.
But I see that `focus` doesn't work right for a canvas in a floating
frame, like the one used by `interactive`, so the example below doesn't
work with the current release or snapshot. I've pushed a repair to
`focus` for the next snapshot build. I don't have a workaround for the
current version, but I might be able to find one if that's needed.
----------------------------------------
#lang slideshow
(require racket/gui/base)
(define (make-pasteboard f)
(define c%
(class editor-canvas%
(super-new)
(inherit focus)
(define/override (on-superwindow-show on?)
(when on?
(focus))
(super on-superwindow-show on?))))
(define pb (new pasteboard%))
(send pb insert-box) ; to demonstrate focus
(new c% [parent f] [editor pb])
void)
(slide)
(slide
#:title "Example"
(interactive (blank 500 500)
make-pasteboard))
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