Bitmap Export Bug / 3.22.1.0

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Colditz
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Joined: Sun Jun 09, 2019 6:58 am

Bitmap Export Bug / 3.22.1.0

Post by Colditz » Sun Jun 09, 2019 7:06 am

Hi there,

after upgrading from 3.20 to 3.22.1.0 I have a strange bug exporting to Bitmaps with the same file. Somehow its ignores the line weights.

Upper picture is before the Upgrade, the second one is after the Upgrade. Lines are displayed very thin.

Exporting to PDF works as before and shows the correct line weights. :?:
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M998.jpeg
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Skizzen.jpeg
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andrew
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Re: Bitmap Export Bug / 3.22.1.0

Post by andrew » Mon Jun 10, 2019 8:47 am

Thanks for your report.

Please attach or e-mail your DXF file, so we can try to reproduce the problem here, thanks.

Colditz
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Joined: Sun Jun 09, 2019 6:58 am

Re: Bitmap Export Bug / 3.22.1.0

Post by Colditz » Tue Jun 11, 2019 7:54 am

Hi Andrew,

I sent the DXF file via eMail, thank you.

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andrew
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Re: Bitmap Export Bug / 3.22.1.0

Post by andrew » Tue Jun 11, 2019 9:01 am

Thanks for the file.

The export (with the thinner lines) seems to be correct. The whole drawing is 1160 Millimeter wide. The lines are only 0.3mm thick. It is possible that this was wrong in the older version.

Colditz
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Joined: Sun Jun 09, 2019 6:58 am

Re: Bitmap Export Bug / 3.22.1.0

Post by Colditz » Tue Jun 11, 2019 10:53 am

Weird thing is, if I set the thickness to 1 mm for the line, the BMP bitmap looks okay but the PDF export is way to much.

Page size is still 260 x 130 mm as PDF.

I dont get it.
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andrew
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Re: Bitmap Export Bug / 3.22.1.0

Post by andrew » Tue Jun 11, 2019 4:05 pm

PDF export is fundamentally different from bitmap export.

When exporting to PDF (or printing), a lineweight of 1mm means that a line is exported (or printed) as 1mm wide on paper (regardless of the drawing scale used). In your case, the drawing scale is 1:5, so a 1mm thick line is 1mm thick on paper, but 5mm in drawing units.

When exporting to a bitmap, there is no absolute paper size. The width of a bitmap in Millimeters is a matter of interpretation (not bearing in mind formats which support a resolution). For bitmaps, lineweights are exported in drawing units. I.e. a 1mm thick line is as thick as a 1mm long line is long.

Layer states offer a potential solution:
https://qcad.org/tutorial-working-with-layer-states

Another way to make them look the same would be to export your PDF 1:1 to a larger page size.

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