Vladimir Prus wrote:
Joel de Guzman wrote:
I'm not sure about this. Say for example that I am writing a WYSIWYG CAD application and I'd like to draw vertical and horizontal rulers. At 100% page view, I'd like the ruler to be a 1:1 with the actual screen at the designated resolution (say 72 DPI). How would I draw my ruler if the coordinates are abstracted in terms of percentage?
You mean the the rule has millimeters as the unit an at 1:1 zoom you want 1 millimeter of the ruler to be 1 millimeter on the screen? Then yes, you'll need some way to convert millimetres to units used on screen. Though I don't understand why you want such strict equality. You won't measure distances on the screen with a physical ruler anyway, right?
Yes ! I think that's exactly the point. If the user doesn't *explicitely* set a different scale, an object's physical size expresses how it wants to be rendered on the output device. Why should users ever have to think about 'device coordinates' ? Regards, Stefan