Tk Source Code

As reported by https://github.com/python/cpython/issues/103216. Tcl equivalent of reporter’s Tkinter script:

package require Tk
grid [canvas .c -height 250 -width 250]
set rect [.c create rectangle 40 40 180 180 \
	-fill red \
	-activefill green2 \
	-activeoutline green3 \
	-activewidth 4 \
	-disabledfill grey \
	-disabledoutline grey2 \
	-disabledwidth 4
]
grid [button .b1 -text disable -command {
	.c itemconfigure $rect -state disabled
}]
grid [button .b2 -text normal  -command {
	.c itemconfigure $rect -state normal
}]

See attached patch: .customPtr being set to &pixelOption (rather than NULL) means that .type is incorrectly being set to TK_CONFIG_PIXELS rather than TK_CONFIG_CUSTOM.

Right and well spotten, many thanks. This was here since the beginning of Tk and the fix is now merged in core-8-6-branch and trunk.

Note: “ignored” may not be the only possible practical effect of this bug. I would think that what actually happens depends on whatever rectOvalPtr->outline.disabledWidth is initialized or set to, such as from contents of the buffer returned by ckalloc(typePtr->itemSize) (i.e. ckalloc(sizeof(RectOvalItem)) or whether Tk_GetPixels() only overwrites mantissa bits (on little endian systems) or more dramatically overwrites exponent bits (on big endian systems).