Re: [Docutils-develop] positioning with the image directive

[David G. <go...@py...>]

On Thu, Dec 18, 2008 at 15:54, m h <ses...@gm...> wrote:
> For rst2odp, I want to provide both horizontal and vertical
> positioning of images.  Currently only one or the other is available.

The reasoning is given in
http://docutils.sourceforge.net/docs/ref/rst/directives.html#image,
"align" option:

    The values "top", "middle", and "bottom"
    control an image's vertical alignment (relative to the text
    baseline); they are only useful for inline images (substitutions).
    The values "left", "center", and "right" control an image's
    horizontal alignment, allowing the image to float and have the
    text flow around it.

With flowed-document layouts like HTML, vertical alignment of
block-level images makes little sense. With inline images, vertical
alignment relative to the text does make sense though.

With slides (and other paged layouts), vertical alignment may make
sense. But relative to what? The "align" option specifies how an image
relates to the text around it. It may make more sense to specify
positioning differently, and with more precision.

> (Note that there seems to be a bug in images.py/run where it's
> checking for align_v_values or align_h_values.  One is only checked if
> self.state isinstance of SubstitutionDef.  Seems like a bug to me,
> since I never ran where that was true.)

Not a bug, given the reasoning above.

> Also, I'd like to a fit to screen/crop property (ie, scale the image
> to fill the whole screen (may cause stretching), fit to screen with
> cropping, or expanding fit to screen (where some of the image might
> not be visible).  This seems to be somewhat specific to presentations.

Or to pages.

> Any suggestions for changing/fixing the directive to support this.  I
> can probably hack out something that works for me, but I assume the
> powers that be might want some input into it.  So I thought I'd ask
> before grinding away and creating a patch.

I don't know if a change to that directive is best, or the addition of
a new facility. Perhaps a generic positioning interface that can
specify positions relative to sections and other elements.

On the other hand, when there's a need for something so
layout-specific, it may be getting too far from the underlying
philosophy of Docutils. It needs discussion.

-- 
David Goodger <http://python.net/~goodger>