#96 ScrolledHList continuous redraw on Mac Aqua

[Tom Goddard]

A Tix 8.4.3 ScrolledHList with a header continuously redraws itself when nothing is changing using ~60% CPU on Mac OS 10.4.11 or Mac OS 10.5.3 with Aqua Tk 8.5.2.

The high CPU use is not observed on the Mac X11 Tk 8.5.2.

This may be a bug in Aqua Tk 8.5.2.

Changing tixHList.c WidgetDisplay() so that Tk_MoveResizeWindow() is not called unless the position or width or height actually changes fixes the problem. Apparently the Tk_MoveResizeWindow() call is generating new exposure events even when the position and size does not change. The Tk_MoveResizeWindow() call in tixDiWin.c likewise causes continuous redrawing when a "window" entry is put in the ScrolledHlist.

The following Python script demonstrates the problem. Run it using Aqua Tk 8.5.2 and measure CPU use with the unix "top" command or equivalent.

import Tkinter
f = Tkinter.Frame()
f.pack()
f.tk.call('package', 'require', 'Tix')
import Tix
Tix.ScrolledHList(f, options='hlist.header 1').pack()
Tkinter.mainloop()

[Tom Goddard]

Python script demonstrating high CPU use.