#2118 Tabbed text alignment on highest levels of zoom out

[Larry H]

Platform: Notepad++ 7.7.1 on Windows 10

In the Document Map and at the highest 3 levels of zoom out (Doc Map is just a zoomed out view) the alignment of text containing tabs is no longer correct. Some rows display an additional tab with no obvious pattern.

See attached image - the orange datatypes in this SQL script are all aligned with 4 character tabs. There are no other characters between the white field names and datatypes, just tabs.

[Neil Hodgson]

This could be a loss-of-precision or rounding to integer issue. One factor that could influence this is whether the view is using GDI (technology=0, integer widths) or DirectWrite (technology=1, floating point widths).

You should attach the file that showed the issue.

[Zufu Liu]

I think it's mostly happens on GDI.
The screenshot tested this file with DejaVu Sans Mono 11pt at 100%.
https://github.com/zufuliu/notepad2/blob/master/src/Notepad2.rc

Happens on D2D too when extremely zoomed out (<= 22%).

[Larry H]

Thanks for confirming Zufu Liu. Attaching a sample SQL script.

Did consider if it was some sort of rounding or odd/even thing as on average half the lines are correct and half not.

[Neil Hodgson]

This is caused by the minimum tab width which is set to 2 pixels. This ensures that tabs are always visible.

For a document map where there is no need to see every detail, this value could be made changeable by the application with a new API.

You can experiment by changing the value assigned to tabWidthMinimumPixels in the EditView constructor.

[Zufu Liu]

Set tabWidthMinimumPixels to 1 fixed the problem.

[Neil Hodgson]

A proposed SCI_SETTABMINIMUMWIDTH API change set is attached. Includes a generic SetAppearance method.

[Zufu Liu]

Is this bug also affect printing?

vsPrint.zoomLevel = printParameters.magnification;

[Neil Hodgson]

Its possible but printers are commonly higher resolution than screens so less likely.

[Neil Hodgson]

For the change to progress there needs to be confirmation that it works correctly in the target application.

[Zufu Liu]

It works. I found it only need to set when font size is smaller than 3.5pt.
https://github.com/zufuliu/notepad2/commit/82c40f3252509d26a409293d69d3b54a4db8155e

[Neil Hodgson]

The bug is against the document map in Notepad++, not Notepad2. What I want here is assurance that this change will actually be useful in the context of document maps (sometimes called mini-maps) and in particular, the patch is correct for the document map in Notepad++.

[Zufu Liu]

I don't know where to add SCI_SETTABMINIMUMWIDTH call in Notepad++, but build SciLexer.dll with hard-coded 1 for tabWidthMinimumPixels works.

[Neil Hodgson]

Committed new API as [ed73f7], [e6efe0].

[Neil Hodgson]

Committed new API as [ed73f7], [e6efe0].