[cairo] 回复： 回复： From China: About 2.5D transform

[唐博]

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 <mkbosmans at gmail.com>
收件人： 唐博 <hitiger.2008 at yahoo.com.cn>
cairo at cairographics.org
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

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2011/10/9 唐博 <hitiger.2008 at yahoo.com.cn>:
> 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 <mkbosmans at gmail.com>
> 收件人： 唐博 <hitiger.2008 at yahoo.com.cn>
> 抄送： "cairo at cairographics.org" <cairo at cairographics.org>
> 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 <hitiger.2008 at yahoo.com.cn>:
>> 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
>

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