Re: 回复： 回复： From China: A bout 2.5D transform

You should be able to achieve *orthogonal* projection matrix using shear *
rotation (or vice versa, dunno) matrix, try to construct one, then use
set_matrix on the context.

2011/10/11 Jerónimo Barraco Mármol <[email protected]>

> im intrested in this too, but failed to achieve it...
> i think the only way is using the correct values as parameters when
> creating a matrix.
>
> Jerónimo Barraco Mármol
>
> http://nande.com.ar
> http://ar.linkedin.com/in/nande
> ------------------------------
> *De:* 唐博 <[email protected]>
> *Para:* Maarten Bosmans <[email protected]>
> *CC:* "[email protected]" <[email protected]>
> *Enviado:* martes, 11 de octubre de 2011 0:23
> *Asunto:* [cairo] 回复： 回复： From China: About 2.5D transform
>
> Oh, it's the first time I send email to mailing list. I 'm not familiar
> with it, excuse me.
>
> ----- 原邮件 ----
> 发件人： Maarten Bosmans <[email protected]>
> 收件人： 唐博 <[email protected]>
> [email protected]
> 发送日期： 2011年10月10日, 星期一, 上午 2:20
> 主题: Re: 回复： [cairo] From China: About 2.5D transform
>
> Note: Please keep the conversation on the mailing list. (use reply-to-all)
>
> Also inline answering instead of top posting is preferred.
>
> 2011/10/9 唐博 <[email protected]>:
> > Thank you very much！
> >
> > I want to transform the image rotate as the Z axis. And achieve overlook
> effect .I don't know whether cairo support .
>
> This is indeed projective transform. I wouldn't call this 2.5D.
>
> A year ago I strarted of a discussion about this.
> http://lists.freedesktop.org/archives/cairo/2010-August/020458.html
> Please read through it and the patches I proposed. Perhaps you would
> like to put in some effort to bring projective transforms to Cairo,
> that would be much appreciated.
>
> Maarten
>
> > ----- 原邮件 -----
> > 发件人： Maarten Bosmans <[email protected]>
> > 收件人： 唐博 <[email protected]>
> > 抄送： "[email protected]" <[email protected]>
> > 发送日期： 2011年10月9日, 星期日, 下午 6:49
> > 主题: Re: [cairo] From China: About 2.5D transform
> >
> > 2011/10/9 唐博 <[email protected]>:
> >> Good afternoon:
> >>     How can I use cairo lib achieve 2.5D effect ?
> >
> > Can you explain what you want to achieve in more detail?
> > With 2.5D I always understood having multiple flat layers stacked on
> > top of eachother. This is of course exactly what Cairo does.
> >
> >> I want to use affine transform, but I don't know how to set the matrix's
> param.
> >
> > http://cairographics.org/manual/cairo-Transformations.html
> >
> > If you want a perspective transform (which is not affine), then that's
> > currently not possible to do with Cairo. It is possible in pixman and
> > I proposed some patches to cairo to expose that functionality, but
> > those where met with complaints about the API. I haven't revisited
> > those.
> >
> > Maarten
> >
>
> 抄送：
>
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