[Solved] Slow first use of large knobs on Mac (VSTGUI 4.3)

We have a plug-in with rather large knob bitmaps. (The graphics are over 10Mb in normal resolutions, and over 30Mb in HiDPI 2x mode.) In our AAX and AU versions on the Mac, the first time that one of these knobs is changed by the user after opening the GUI, it takes at least 2 seconds before the knob responds. We found some old mention of a somewhat similar problem using older 4.x VSTGUI versions, but that was for 32-bit only, and our software is 64-bit.

It seems strange that this only happens the first time one of these knobs is moved, because the knobs have already been drawn to their default positions when opening the GUI, which required loading the bitmaps. But maybe our large bitmaps are cached (again?) when the user first starts moving a knob? That’s the only thing I can think of as to what might cause such a large delay.

Anyone know what might be going on here, and how to fix it? (O if this has been addressed already in a later VSTGUI version?)


Never mind. It was a constant refresh of a large display in the GUI that was taking the time away from the initial responsiveness of the knobs. Once we removed that repeated invalidation, the knobs responded as expected.