#19 Width=0 canvas lines are drawn width=1

[Brent B. Welch]

OriginalBugID: 2298 Bug
Version: 8.1.1
SubmitDate: '1999-06-28'
LastModified: '1999-10-21'
Severity: LOW
Status: Closed
Submitter: techsupp
ChangedBy: hobbs
OS: Windows 95
OSVersion: 4.00.951
Machine: X86
ClosedDate: '1999-10-21'

Name:
John Nakulski

ReproducibleScript:
canvas .c
pack .c
.c create line 1 1 50 50 -width 0 ;# Draws a line of width 1

ObservedBehavior:
Canvas lines of width<=0 are drawn as if width=1

DesiredBehavior:
If I specify line width=0, I expect the line to be invisible (but to
exist, so that I can later configure the width to be positive).

If I specify width<0, I expect to get an error.

This is actually a feature of X that you can say 0, but you always
get at least a 1 pixel line. The ability to make items invisible
in general is being considered for a future release of Tk.
-- 10/21/1999 hobbs

[Donal K. Fellows]

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Invisible lines can be obtained by setting -fill (or
-outline, depending on item type) to the empty string.
Given my experience with X, I'd expect zero to draw a
"narrowest visible" line (in some device-dependent sense).
Negative widths should always be errors, as they're nonsensical!

[Donal K. Fellows]

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Note that you see the difference between lines with -width 0
and -width 1 when you generate and scale PostScript.

[Donal K. Fellows]

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Looks like a docfix to me