In the epub export dialog, we're given the option of exporting images
"relative to page". Meaning (as far as I can tell) that if, in the
layout, the image is 20% away from the left edge and 20% away from the
right edge of the page, then in the ePub it will also be 20% away from
the left edge of the viewing area, and 20% from the right edge.
I think it's important to have an additional option: "relative to margin".
The fact is that in book design, margins play a much more important role
than in ePubs, where viewing area is at a premium. In much good book
design you will find that an image extends only to the margins of the
text area and not beyond (unless of course it's a full-bleed image,
etc.) In ePubs, though, the effective text area is normally the edge of
the device screen (minus a few pixels, perhaps). Thus the edge of the
ePub viewing area is essentially analogous to the text-area margins of
the printed page -- much more so than to the edge of the printed page.
So I, as a book designer, would want an option that says that whenever
an image extends all the way to the text-area margins, it should fill
the ePub screen.
I'm now working on a converting a printed layout to ePub. The images
extend in most cases only to the text-area margins, and the margins
themselves are fairly generous in the printed edition, and this means
that when the images are exported to ePub, they are taking up far too
little screen area, since the only option is to calculate their size as
a percentage of the entire page area ("relative to page").
The workaround is to go through the book enlarging the images so that
they extend to the page edges rather than to the text area margins and
then exporting. But this book has many images.
This superfluous extra effort could be avoided if the ePub export dialog
simply gave the option to export images "relative to margins."
Hope that makes sense!
Thanks for reading,