Electrolysis/Meetings/2009-08-26-macplugins

Multi-process plugins on mac: architecture questions

• support CoreGraphics
  • invisible carbon window of the appropriate size
  • bitmap context in shared memory
  • CGBitmapContext
  • Plugin may only draw while it's processing an update event.
• hope to have something similar for quickdraw (quicktime)
• but it's not working correctly

Chrome supports asynchronous drawing model for plugins:

• drawing is synchronous from the plugin POV
• but asynchronous from the renderer point of view (saved backing store)

Patching over carbon APIs:

• detect when native windows are opened/active/closed/modal window management

Testing:

• currently Chromium has some tests against real plugins (Flash)
• but no tests with custom-purpose test plugins which exercize these features

Future:

• new CoreAnimation drawing model
  • plugin creates CALayer
  • host has CARenderer
  • uses SPI (system private interface)

In 10.6:

shared IOSurface (GL context) which can be attached to a CARenderer

In leopard (and earlier):

• CGSxxxSurface APIs let you share an opengl drawable across process
• But it's a hidden API
• And there are locking/fragility issues

But since we have IOSurface on 10.6 and <=10.5 aren't actually going to change, it may be safe to use these APIs only when IOSurface is not available.