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Re: Image transformations
From: |
Eli Zaretskii |
Subject: |
Re: Image transformations |
Date: |
Thu, 13 Jun 2019 22:47:38 +0300 |
> Date: Thu, 13 Jun 2019 20:27:24 +0100
> From: Alan Third <address@hidden>
> Cc: address@hidden
>
> I think this should be what you need:
>
> x’ = tm[0][0] * x + tm[0][1] * y + tm[0][2] * 1
> y’ = tm[1][0] * x + tm[1][1] * y + tm[1][2] * 1
>
> where tm is the completed transformation matrix.
Thanks.
> BTW, are you aware that you can use the XFORM struct:
>
> https://docs.microsoft.com/en-us/windows/desktop/api/wingdi/ns-wingdi-xform
Yes, I'm using it.
> > I also want to know when no rotation is involved, so that I could use
> > the existing code (which only supports scaling and will be modified to
> > support cropping) on older Windows versions that cannot support
> > rotations (PlgBlt is not available on those platforms).
>
> I’d be inclined to just skip image_set_rotation when on a platform
> that doesn’t support it.
That'd mean putting too much w32-specific code in image.c, something
I'd like to avoid if possible.
> Or storing the basic crop and scaling information separately so you
> don’t have to worry about the matrices at all.
I'm beginning to think we should do this on all platforms, and leave
the matrix calculation, if needed, to the terminal-specific back-ends
(xterm.c, w32term.c, etc.). It sounds like we gain nothing by
spilling XRender-specific stuff in image.c and letting all the other
platforms adapt.
- Re: Image transformations, (continued)
- Re: Image transformations, Alan Third, 2019/06/13
- Re: Image transformations, Eli Zaretskii, 2019/06/13
- Re: Image transformations, Richard Copley, 2019/06/13
- Re: Image transformations, Eli Zaretskii, 2019/06/13
- Re: Image transformations, Alan Third, 2019/06/13
- Re: Image transformations, Eli Zaretskii, 2019/06/13
- Re: Image transformations, Alan Third, 2019/06/13
- Re: Image transformations,
Eli Zaretskii <=
- Re: Image transformations, Alan Third, 2019/06/13
- Re: Image transformations, Eli Zaretskii, 2019/06/14
- Re: Image transformations, Stefan Monnier, 2019/06/14
- Re: Image transformations, Eli Zaretskii, 2019/06/14
- Re: Image transformations, Richard Copley, 2019/06/14
- Re: Image transformations, Eli Zaretskii, 2019/06/14
- Re: Image transformations, Richard Copley, 2019/06/14
- Re: Image transformations, Yuri Khan, 2019/06/14
- Re: Image transformations, Eli Zaretskii, 2019/06/14
- Re: Image transformations, Richard Copley, 2019/06/14