On Sun, 2 Jan 2005, Peter Moulder wrote:
Maybe these issues can be handled with the unit menu: whether the number should be interpreted as an effective width on page (under some assumption about px/in), or whether it should be SVG's understanding of the number (subject to transforms).
A related note about units: People have been suggesting that km etc. should be added to the units menu, but I don't think we should be interpreting `10km' as `2822222.22px': partly because that's beyond the range of SVG Tiny (and I think SVG Basic), which can only represent numbers in the range +/-32767.9999. A lesser issue is that clearly we don't want to use up 10km of paper when printing such a document. If the diagram is to scale then the diagram may well include a legend with a `hard-coded' statement of scale, in which case we want that scale to be the default when printing, even if a program other than inkscape prints the SVG file.
Hmm, this is a good point...
Maybe what we're dealing with is two different types of units for measuring length: Document distance and Scaled distance.
Document distance (px, pt, in, cm, mm, etc.) corresponds exactly to measurements on the printed document.
Scaled units make use of a document-specific scaling factor. For instance, a document my use a scale_factor of 1 cm : 1 km.
I can imagine that a given unit could be *both* document and scaled. For instance, 'm' is an allowed document unit in SVG, but I could imagine creating a landscaping plan using meters at a scale of 1 cm : 1 m. So the system may need to be smart about allowing a given unit name to be either document or scaled. That could be a tricky requirement...
The scaling factor is not a unit property, so wouldn't be stored with the units themselves. I.e., if I'm at a particular scale, I want to be able to switch units from km to mi to furlongs and back without losing accuracy.
Now, how should this affect the dialog unit widgets? Perhaps the user sets a document preference to indicate that the document is 'scaled', which flips all of the dialog unit widgets from document units (px, pt, in, et al) to the scaled units (km, mi, ft, etc.)
Another question is - how do we store this information with the document? This is really two questions - first how to store the scale factor (I imagine adding a new inkscape: property? Or is there something standard in SVG?) and second how to store the numbers (I guess as pt's or px's?)
Bryce