Participant

P: Photoshop Line Tool: dashed stroke tilts & clips when using Arrowheads

Forum|Forum|4 days ago
August 15, 2026
6 replies
69 views

Hi Adobe Photoshop team,

my name is Gianpiero Veronio. I use Photoshop regularly for graphic and cover-art work, and while working on a recent project I noticed a reproducible geometry/rendering issue with the Line Tool.

I was able to reproduce the behavior consistently, so I prepared a short report with screenshots and technical notes in case it may be useful to the Photoshop engineering team.

Issue summary

When a dashed stroke and an arrowhead are used together on a Line shape, the line becomes visibly tilted even though the Transform rotation remains at 0.00°.

Steps to reproduce

Create a line as a Shape using the Line Tool.
Set the stroke width to 10 px.
Apply a dashed stroke.
Make sure the line rotation is exactly 0.00°.
Enable an arrowhead on the line.

Actual result
The dashed line becomes visibly inclined while the Transform panel still reports 0.00° rotation.

Expected result
Adding an arrowhead should affect the arrowhead geometry only. A line at 0.00° rotation should remain horizontal.

I also tested different arrowhead Width and Length values, including equal even and equal odd values, and the behavior remained reproducible. A comparable dashed line without the arrowhead remains horizontal.

I have attached a PDF report containing screenshots, the reproduction procedure, expected vs. actual behavior, and an additional observation that may or may not be related.

Thank you for taking a look at it. I hope the information is useful for reproducing and investigating the issue.

Best regards,

Gianpiero Veronio

Photoshop_Geometry_Bug_Report.pdf

P

Paku380Author

Participant

Hi Dave,
thanks for testing this further and for the detailed explanation.

Just to clarify, the original reproducible case I reported is already documented in the attached PDF, including the exact Line Tool configuration and screenshots. In that case, the stroke is set to 10 px, with a dashed stroke and an arrowhead enabled, while the Transform rotation remains at 0.00°.

I mentioned the Fill-only case afterwards as an additional observation, but I noticed that your latest test was performed using a 1 px wide line, which is not the same configuration as the original documented case.

Would you be able to reproduce the configuration described in the report and compare the result?

Thanks again for taking the time to investigate this.

Gianpiero

davescm

Community Expert

Using 10px stroke width I have not been able to create any tilt on the line (outside of the visual effect of the dashes I mentioned in my earlier reply).
To test for tilt, zoom in until you see the pixel grid, draw a guideline, and check against that. That way you remove any optical effects and and tilt will be visible and measurable.

Dave

davescm

Community Expert

Hi,

Thanks for the very comprehensive bug report.

It looks like what you are seeing is a result of the way the line tool works in Photoshop.

The line tool does not actually draw a line. Instead, it draws a path in the form of a rectangle with a width of 1 pixel. You can see that for yourself by zooming in to see the pixel grid.
A stroke is then placed on that rectangle. By default, that stroke is aligned to the centre of the path. For a solid line that makes little difference, but for a dashed line the dashes are drawn around the ‘rectangle’ i.e. along one side, around the end then back along the other side. Depending on the dashed line settings the two sides may, or may not, line up.

When you add an arrow head, the dashed line now travels along the line, around the arrow head and back along the other side of the line. Therefore, even if the dashes on both sides of the line previously aligned perfectly, they now do not and the dashes can appear to be sloped, or even alternate.

You can adjust the dash settings and the arrow size but it is a bit of a ‘trial and error’ process.

Dave

P

Paku380Author

Participant

Hi Dave,
thank you again for the explanation. I did another check after reading your reply and noticed something that may be relevant.

The apparent tilt is not limited to the dashed-stroke rendering case. I can also reproduce the misalignment when drawing the Line shape using Fill only, with Stroke disabled, while the Transform rotation remains at 0.00°.

I also reproduced it using Stroke only.

If the behavior were caused solely by the dashed stroke travelling around the perimeter of the 1-pixel rectangular path and arrowhead, I would not expect the same visible geometrical misalignment when the stroke is completely disabled.

Could this indicate that the arrowhead/Line Tool geometry itself is involved, rather than only the dash pattern alignment?

Thanks,
Gianpiero

davescm

Community Expert

Thanks for the extra info. I tested drawing a 1 px wide line with fill on and stroke off and could not see any tilt introduced when adding an arrowhead. However, there was an apparent shift in the line. When I looked closely at this it was due to the arrow head point being required to land at a half pixel point which of course cannot be drawn, the minimum unit for drawing being one pixel. The line was therefore changed to 2 px wide but the fill reduced to 50% transparent (as would be done for anti-aliasing of edges). The centre of the line now lies between two pixels rather than the centre of a single line of pixels.
So there is an, unavoidable, change in position introduced by adding the arrow head, but I could not see any tilt.

Note - the screenshot above is zoomed to more than 1700% making the pixel grid clearly visible

Dave

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