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Does QImage::Format_Mono support text antialiasing?



  • Hi,

    I want to generate a Format_Mono bitmap from QPainter drawing some text.
    But the result looks really bad on antialiasing(with antialiasing option enabled).
    when I tried use the ARGB32 format it looked very well.
    So does Format_Mono support text antialiasing? Is there any workaround for it?

    Thanks.



  • Hi itomakoto,

    QImage::Format_Mono is a 1 bit format and then antialiasing is impossible.

    Only 2 level of color...



  • [quote author="Dagal" date="1373537803"]Hi itomakoto, QImage::Format_Mono is a 1 bit format and then antialiasing is impossible. Only 2 level of color... [/quote]
    Hi Dagal, thank you for the reply.
    I am so curious that actually the 1bit-map isn't 'not antialiased', it is generated with some noise pixel.
    For example, if I draw the character 'I', so ideally the pixel map should be like

    oo
    oo
    oo
    oo
    oo
    , suppose 'o' means a pixel.

    But what I got from qt is like

    oo
    oo
    ooo <-- one noise pixel
    oo
    ooo <---another one noise pixel
    oo

    ARGB32 doesn't have this issue.



  • antialiasing create always "noise pixels" lighter or darker color and then, you see soft lines.

    If you have a 1 bit image, you can have white and black pixels (no gray available)

    ARGB32 have the same issue but you don't see it... (16M Colors)


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