[cairo] Implementing cairo_read_func_t/cairo_write_func_t properly

[Behdad Esfahbod]

On 16-01-02 11:27 AM, Enrico Weigelt, metux IT consult wrote:
> On 02.01.2016 11:24, Bernhard Fischer wrote:
> 
> <snip>
> 
> Actually, I really wonder what that stream API is really for.
> Why not just let everything operate on an fd or directly mmap()
> the whole file ?

A very simple reason is language binding, or in general, hooking up to other
IO libraries (gio, etc).


> Instead I'd rather add some callbacks to the image surface, eg. for
> example for releasing or duplicating the raw image data. There're
> lots of interesting usecases for that, for example:
> 
> * allocate image surfaces directly on an BO (or similar buffers on
>   other platforms)
> * zero-copy initialization from already loaded pixmap data, etc.
> * pixmap buffer sharing with other code (outside cairo itself)
> ...
> 
> By the way, I'm currently doing a bit research on using programmable
> DMA controllers for buffer-copying, image composition, etc.
> 
> 
> --mtx
> 
> --
> Enrico Weigelt,
> metux IT consulting
> +49-151-27565287
>