After more discussion with our customers, we have
decided that #3 is not a requirement that is needed
often enough to warrant going into DITA 1.1. Given
that supporting this requirement would require much
more complexity than supporting requirements #1 and #2,
and given that I don't want to hold up DITA 1.1, I
am now suggesting we just implement parts #1 and #2
of my proposed solution below for 1.1.
paul
> -----Original Message-----
> From: Grosso, Paul [mailto:]
> Sent: Monday, 2006 January 23 14:31
> To:
> Subject: [dita] Suggestion for graphic scaling improvements
> in DITA 1.1
>
> I spoke to Don, and he suggested I send a specific
> suggestion for a DITA 1.1 work item to the list
> in the area of graphic scaling.
>
> EXECUTIVE SUMMARY
> =================
> DITA's support for graphic sizing--which just allows
> a number of pixels to be specified for the graphic
> image size via the image element's height and width
> attributes--does not meet our customer requirements.
> I suggest we make some upward compatible changes to
> address at least a subset of these requirements.
>
> DETAILS
> =======
>
> Current situation
> -----------------
> The DITA spec is vague on the topic of what are valid
> values for the image element's height and width
> attributes and what are the semantics of these values.
>
> In checking both the toolkit and the collective IBM
> knowledge, I understand that, for HTML generation, the
> image height and width values are passed through as-is
> implying that DITA's image's height and width attributes
> must be unitless integers giving the number of pixels to
> which to scale the graphic image (in each direction) in
> the browser displayed results. For IBM PDF processing,
> the pixel values are converted to points (assuming 96 pixels
> per inch and 72 points per inch), and that value is used.
>
>
> Requirements for graphic scaling
> --------------------------------
>
> 1. It should be possible for users to specify a percentage
> value to which to scale the intrinsic size of the image.
>
> 2. It should be possible for users to specify an absolute size
> for the image height and/or width using a numeric value and
> unit of measure. Allowable units should include: pc (pica),
> pt (point), px (pixels), in (inches), cm (centimeters),
> mm (millimeters), and em (ems) as allowed by CSS and XSL-FO.
>
> 3. To aid in reuse and minimize hardwiring style to the source,
> it may be a requirement to allow a user to request that an
> image be scaled to some percentage of the "available space".
>
> One specific proposal
> ---------------------
>
> 1. Add the "scale" attribute to the "image" element, and
> change the declared type of the scale attribute to NMTOKEN.
> Define the allowable value space of the scale attribute
> to be any unsigned integer. This would be an upward
> compatible change.
>
> 2. No change needs to be made to the image element's height
> and width DTD declarations, as NMTOKEN would allow all
> values we wish to allow. We would just augment the spec
> to say that the value space of these attributes is a
> length which is a real number with an optional unit
> from the set of pc, pt, px, in, cm, mm, em. An omitted
> unit implies pixels so that existing documents will
> continue to be treated the same way.
>
> 3. This requirement could be met by allowing image element's
> height and width attributes to take % values along with
> some work to define what the "available space" is. The
> specific details of a suggested solution depend on the
> exact user requirements which I'm still researching (and
> would appreciate input from other users).
>
> paul
>
