Are the fields in MS-OFORMS in fmPosition swapped?

Daniel Seiler 0

In MS-OFORMS, specifically https://learn.microsoft.com/en-us/openspecs/office_file_formats/ms-oforms/73c3866f-bbac-4f45-ba70-645fd046bfdf the fmPosition struct is described as "Top (4 bytes)", then "Left (4 bytes)", i.e. vertical offset, then horizontal offset.

This is inconsistent with real world data I have found, such as the example at https://analysistabs.com/vba-code/excel-projects/calculator-userform/ (Download https://analysistabs.com/wp-content/uploads/2022/06/Calculator-using-Excel-VBA.xlsm). In there is a frmCalculator design stream with cmdBtn7, cmdBtn8, cmdBtn9, which are visually on the same row (i.e. same distance to top), but the second value in the stream is identical for all.

It is also inconsistent with fmSize being width, then height, which would be horizontal, then vertical. Is it possible that the specification is mismatched with the product implementation here and should be updated?

Kind regards

Sreekanth Nadendla 321 Reputation points Microsoft Employee

2023-11-04T02:08:49.1366667+00:00

Hello Daniel, thank you for reporting this issue. One of the Open Specifications team members will review your question and assist you soon.

Regards,

Sreekanth Nadendla

Microsoft Windows Open Specifications
Tom Jebo 1,906 Reputation points Microsoft Employee

2023-11-05T19:27:11.35+00:00

Hi Daniel,

I'll take a look at this and get back to you with questions if I have any. Thanks for reporting this.

Best regards,
Tom Jebo
Microsoft Open Specifications Support

1 answer

Tom Jebo 1,906 Reputation points Microsoft Employee

2023-11-07T16:37:43.0766667+00:00

Hi @Daniel Seiler ,

It looks like the assumption that "Top" is a vertical or Y axis measurement is incorrect. The fmPosition struct matches the Windows API POINT structure (x then y). For fmPosition, the correct interpretation is "Top" means horizontal and "Left" means vertical, i.e. "Top" means the position along the top (horizontal) edge of the bounding box and "Left" means the position along the left vertical side of the bounding box.

Does that help to clarify the meaning?

Best regards,
Tom Jebo
Microsoft Open Specifications Support
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Daniel Seiler 0 Reputation points

2023-11-07T18:39:33.3166667+00:00

Hi, while your answer confirms my understanding, that it should by horizontal, then vertical (x, y) as everything else, including the mentioned struct POINT from GDI, I'm confused why you fail to see how this is an error in the spec.

"Position along the top (horizontal) edge of the bounding box" is a description of a coordinate that I've never seen anywhere in 2D-Graphics. In fact it directly contradicts the language in the linked section of MS-OFORMS I posted, which is:

Top (4 bytes): A signed integer that specifies, in HIMETRIC units, a distance below the reference point.

This, in particular the language "below" (i.e. downward direction), is why I asked about "vertical, then horizontal" in the first place.

Tom Jebo 1,906 Reputation points Microsoft Employee

2023-11-07T19:16:58.8733333+00:00

Daniel,

You're right, I didn't take into account the "distance below" and "distance to the right" wording and I now see we need to (edit) swap the two fields. Sorry I missed that. Let me check with the Office forms team and confirm and I'll follow up shortly.

Best regards,
Tom Jebo
Microsoft Open Specifications Support

Daniel Seiler 0 Reputation points

2023-11-07T20:27:55.3766667+00:00

Note that Left, Top (in that order) are standard properties in VBA with well-defined meaning ("The distance between a control and the left or top edge of the form that contains it.", see https://learn.microsoft.com/en-us/office/vba/language/reference/user-interface-help/left-top-properties), so I strongly suggest fixing the field order rather than the wording.

EDIT: this was in reply to the part that has since been edited out, so feel free to disregard.

Kind regards

Tom Jebo 1,906 Reputation points Microsoft Employee

2023-11-07T21:30:00.5666667+00:00

Yup, got it, thanks Daniel.

Tom Jebo 1,906 Reputation points Microsoft Employee

2023-11-08T18:52:53.4866667+00:00

Got the confirmation and I've filed a bug to get the specification fixed. We'll swap the fields. Again, thanks very much for bringing this to our attention.

Tom
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