On Tue, Jun 24, 2008 at 1:49 AM, Carl Worth <cworth@...573...> wrote:
Help me and my inkscape newbie-ness. What's a canvas vs. a regular object?
Canvas items are the helper things that do not correspond to SVG objects - selection frame, knots and handles, bezier controls etc. Here are the cairoified ones:
- switch to the Tweak tool - the orange circle
- start to draw with Pen but not finish it - the green and red path, the node handles
- start to draw with Calligraphic but do not lift the pen - the path you see is a helper canvas item, it becomes a real object when you lift the pen
- the red helper path and the bezier controls in Node tool
You are correct that CAIRO_OPERATOR_XOR, (the Porter-Duff XOR operator), has nothing to do with a bitwise-XOR operation. Cairo doesn't have any bitwise operations, (what would it mean to try to do that when targeting something like a PostScript or PDF target that doesn't have any bits?).
I'm not talking about bits - I'm talking about inversion. For example, inversion is possible in SVG via filters, even though it has no pixels either :) In PDF, of course, it would have to be simulated by adding clipped copies of objects painted by inverse colors - messy but still possible without rasterization.