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delphidxf

Writing text styles into DXF from a Delphi application

I'm writing DXF files from a Delphi application and trying to understand text styles.
I have text styles working in general, but i'm struggling to find information in the DXF reference literature out there about how the 1071 group code works.
The 1071 Group Code is followed by a long value which contains a truetype font’s pitch and family, charset, and italic and bold flags. I cannot find any documentation on how to create this value. I've got sample DXF files produced with a CAD program and in comparing them this value changes, but I cannot make sense of the differences. It looks like each bit in the 4 bytes has a specific meaning. Would appreciate any help. Thanks.

Solution

  • Disclaimer: This answer is my interpretation of findings on a random test. Use at own risk!

    Here a screen shot of test results gotten from a DXF file with random text style definitions:

    enter image description here

    So, it should be safe to assume that:

    • Italic style has the $01000000 bit set,
    • Bold style has the $02000000 bit set,
    • The 1st Word of the value designates the family charset.

    Then the challenge left seems to be to get the family charset value. You could try to omit it since it is defined by the font name and filename. However, a test with deleting the whole 1071 group also clears the font style, although that is even so defined by the font filename.