[Vm-dev] new VM breaks window dragging in old images. that's not backwards compatibility in my book.

Marcel Taeumel marcel.taeumel at hpi.de
Wed Apr 27 07:19:12 UTC 2022


Hi Eliot --

No, this cannot be preserved on the VM side without again introducing that major performance regression that has been there for several years now on the macOS platform. I strongly argue that we keep the VM platform code this way.

However, it can *very easily* be fixed in most (if not all) older images. Just disable deferred (display) updates as it was not supported on macOS for a very (!) long time:

   PasteUpMorph disableDeferredUpdates: true.
   Project allMorphicProjects do: [:ea | ea world canvas: nil].

> To reproduce take e.g. Squeak 6.0 alpha [...]

No, Squeak6.0alpha (Trunk) does not show this issue unless it is not an updated image. Still, this update has been part of the update stream for several weeks now.

> [...] or the ;ast of the 5.x line [...]

The above snippet accounts for this *very easily*. It even works in Squeak 4.x. This is an image-side thing. It always has been. Since 1999. This is not a VM issue.

Best,

Marcel

P.S.: Keep in mind that ST80-style "Fast dragging" is always an alternative in older images:
   Preferences enable: #fastDragWindowForMorphic.
Am 27.04.2022 03:29:31 schrieb Eliot Miranda <eliot.miranda at gmail.com>:
Hi Marcel,

the issue of windows being invisible when dragged in the new VM is a
major bug. The VM needs to be backwards compatible. It souldn't break old
images. So we need to find a way of restoring the default behaviour in
images that don't set the relevant preference.

To reproduce take e.g. Squeak 6.0 alpha or the ;ast of the 5.x line and
simply try and move a window about As soon as the window starts to move it
disappears and then reappears when the mouse button is released. This must
be fixed.
_,,,^..^,,,_
best, Eliot

Hi Marcel,

    the issue of windows being invisible when dragged in the new VM is a major bug.  The VM needs to be backwards compatible.  It souldn't break old images.  So we need to find a way of restoring the default behaviour in images that don't set the relevant preference.

To reproduce take e.g. Squeak 6.0 alpha or the ;ast of the 5.x line and simply try and move a window about  As soon as the window starts to move it disappears and then reappears when the mouse button is released.  This must be fixed.
_,,,^..^,,,_

best, Eliot
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