Tk Source Code

OriginalBugID: 1274 Bug
Version: 8.2
SubmitDate: '1999-02-23'
LastModified: '2000-04-03'
Severity: SER
Status: Assigned
Submitter: pat
ChangedBy: ericm
RelatedBugIDs: 1379 555 610 4081 4077 2495
OS: All Windows
Machine: X86


Name:
Christopher Nelson

ReproducibleScript:
canvas .c
pack .c
.c create oval 1i 1i 2i 2i -fill black -stipple gray50

ObservedBehavior:
The oval is drawn black, no fill pattern.

DesiredBehavior:
A 50% gray oval.





Stippling is not yet (as of 8.2.0 still) implement for non-Unix platforms. 
-- 08/14/1999 hobbs
Some aspects of stippling work, but not most (see 4077, 4081). 
-- 03/27/2000 hobbs

Thank you, Jan. The differences are probably caused by the color space conversion on macOS. stippleColors in canvas.test and canvRect.test could compare the colors with a small tolerance, as pixelNear in imgPhInstance.test does.

> it can be removed when the macos-stipple branch is merged

Unfortunately, the notAqua constraints cannot be removed yet.

The macOS changes itself are now merged to trunk and core-9-0-branch too.

I'm seeing:

canvRect.test
==== canvRect-13.1 stippled oval fill - bug 220787 FAILED
==== Contents of test case:
    .c create oval 10 10 110 110 -fill red -stipple gray50 -outline {}
    update
    stippleColors .c 60 60
---- Result was:
#ff0200 #ffffff
---- Result should have been (exact matching):
#ff0000 #ffffff
==== canvRect-13.1 FAILED
==== canvRect-13.2 stippled oval outline - bug 220787 FAILED
==== Contents of test case:
    .c create oval 10 10 110 110 -fill {} -outline blue -outlinestipple gray50 -width 6
    update
    stippleColors .c 60 10
---- Result was:
#0301ff #ffffff
---- Result should have been (exact matching):
#0000ff #ffffff
==== canvRect-13.2 FAILED
==== canvRect-13.3 stippled rectangle outline - bug 220059 FAILED
==== Contents of test case:
    .c create rectangle 10 10 110 110 -fill {} -outline blue -outlinestipple gray50 -width 6
    update
    stippleColors .c 60 10
---- Result was:
#0301ff #ffffff
---- Result should have been (exact matching):
#0000ff #ffffff
==== canvRect-13.3 FAILED

canvText.test
canvWind.test
canvas.test
==== canvas-27.1 stippled arc fill - bug 220787 FAILED
==== Contents of test case:
    .c create arc 10 10 110 110 -start 0 -extent 90 -style pieslice -fill red -stipple gray50 -outline {}
    .c create arc 10 10 110 110 -start 180 -extent 90 -style chord -fill blue -stipple gray50 -outline {}
    update
    list [stippleColors .c 80 40] [stippleColors .c 35 95] [testpixel .c 40 40]
---- Result was:
{#ff0200 #ffffff} {#0301ff #ffffff} #ffffff
---- Result should have been (exact matching):
{#ff0000 #ffffff} {#0000ff #ffffff} #ffffff
==== canvas-27.1 FAILED
==== canvas-27.2 stippled arc outline - bug 220787 FAILED
==== Contents of test case:
    .c create arc 10 10 110 110 -start 0 -extent 180 -style arc -outline blue -outlinestipple gray50 -width 6
    update
    list [stippleColors .c 60 10] [testpixel .c 60 110]
---- Result was:
{#0301ff #ffffff} #ffffff
---- Result should have been (exact matching):
{#0000ff #ffffff} #ffffff
==== canvas-27.2 FAILED

The new stipple tests failed on Aqua in CI, since Aqua does not support stippling yet. I added the notAqua constraint to canvas-27.1, canvas-27.2 and canvRect-13.1 to 13.3 in [e277e5e56a]; it can be removed when the macos-stipple branch is merged.

Does the macos-stipple branch accomplish what is needed here? I took Christopher's suggested API and screen shot as an example - see my attached screen shot.

I have a stale draft implementation of stippling for Aqua from a few years ago: see [3bfa5eb4] if interested.

Stippling is not, to my knowledge, supported on CoreGraphics/macOS.

Tested on MacOS as well... I see a black oval, no fill pattern.

Conclusion: a similar fix will be needed for MacOS too.

Fixed in [f34f83d4e1f75181|trunk]. Tested on Windows: just works fine!

If CI is OK, can be backported further.

Re-tested on Windows 11 with today's main: stippled ovals, arc pie slices and rectangle outlines are still drawn solid. Branch win-canvas-arc-stipple still fixes all of them, and canvas.test, canvRect.test and canvArc.test pass with it. The Windows part is ready for review; the macOS part is still open.

On Windows the stipple of the GC was ignored when drawing arcs (fill and outline of arc, oval and chord/pie-slice items) and rectangle outlines, while polygons, lines and rectangle fills honoured it. Fixed in [72e46db680] (branch win-canvas-arc-stipple): the rendering through the stipple pattern used for polygons and lines is moved to a shared RenderStippled() and used for arcs and rectangle outlines too, so the -fill/-outline colors are honoured and opaque stipples use the background color. This also covers the closed duplicates [220059] (rectangle -outlinestipple) and [220058] (oval -stipple/-outlinestipple).

Tests canvRect-13.1, 13.2, 13.3 and canvas-27.1, 27.2 check the stippling with testpixel; they pass on X11 and on Windows with the fix and fail on Windows without it. The rendering of a canvas with stippled ovals, arcs of the three styles, rectangles, polygons and lines is now the same as on X11 up to rounding at the curve edges.

The macOS part is not addressed; I cannot test on macOS.

Link to the patch proposed ten years ago that I just rediscovered: [1493260fff]

See [f3e40e98d4] for an attempt of a fix.

Still not fixed in Tk 8.6b1

I installed Activestate Tcl 8.5.5.0 a while back.  This bug is still present.  Is there some problem with the patch?

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I've tested this bug using Tk 8.5.2.0.284581 (teapot) on both Windows XP Pro and Mac OS X 8.4. 

The issue is still present on both platforms. Did the patch provided by 'nobody' on 2006-05-23 16:09 get tested or applied?

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Xref: patch 1493260

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I am posting the code in the patches section.

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I have fixed the bug to my satisfaction on my machine.  I'd
like someone to look it over for integration into the main
code.  What is the best way to go about that?

Thanks!

The fix makes use of
http://msdn.microsoft.com/archive/default.asp?url=/archive/en-us/dnargdi/html/msdn_transblt.asp

It is about 60 lines of code.  I am uncertain of the usage
of FillOpaqueStippled, so I am probably doing that wrong.

It seems possible to restructure the rectangle version to
be more like this, and possibly set up a function that both
could use.

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Is someone working on this bug?  It impacts me directly, so
I will fix it if necessary.  Please email me if I need to
fix this.

Thanks!

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doc update applied; keeping open as it would still be nice
to fix the bug (if possible)

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As of Aqua Tk 8.4.12 rectangles ignore stipple. I've not
tried other canvas shapes.

May I suggest adding a warning to the documentation about
using stipple on non-unix platforms?

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It most certainly works on unix, but remember that you need
to use -outlinestipple.

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As of TclTk 8.4.9 oval outlines, and the curved part of arc
outlines, do not stipple on _any_platform_!

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For 8.3.4, stippleborders work for polygons, but
not for rectangles (Win NT).

Confirmed in 8.3.0.  And at the same time I noticed that thick ovals (-width 5) don't look to me to have a constant width on this Win98 machine at least.  Strange...