papyrus Canvas Library

This release features both bugfixes and enhancements. A bug causing segfaults in Drawable's destructor that removed a child from a parent was fixed. Fixing this bug allowed the base Papyrus::Object to inherit from sigc::trackable again. The Group::clear() method has been cleaned up and improved. This should result in a fairly significant performance improvement if you have many items in a group and regularly clear it. A simple estimate would put the old version at a performance level of 3 * O(n lg(n)) + O(n) and the new version at 4 * O(n).

This is primarily a bugfix release. There was an overload resolution bug with the virtual and non-virtual render() methods. Because of scoping rules, the virtual methods were not seen by descendants of Renderable,
causing an infinite recursion of the virtual method resulting in a segfault. To remedy this, two new macros have been created: PAPYRUS_RENDERABLE()
and PAPYRUS_DRAWABLE(). These macros add a using directive to ensure the overload resolution resolves to the virtual render() methods.

This release adds support for linear and radial gradients. The paint hierarchy has also been restructured and as a result a new wrapper for cairo contexts has been implemented that includes internal state values. The Paint class is now a top level ancestor for all paints, including the gradients. The former solid colors that were supplied by Paint can now be found in its descendant Color. Other changes include a fix in ScrolledViewport for a display bug and the restructuring of several primitives such as Point, Vertex, and LineSegment.

This release modifies the basic demo by adding support for scrolled viewports and zooming on the shapes. New shapes are Deltilles, Hextilles, and Quadrilles.

This release features a new controller called Zoomer providing mouse wheel zooming of drawables. There is a new viewport widget named ScrolledViewport. It contains a basic viewport, but adds vertical and horizontal scrollers and provides an API very similar to Gtk's ScrolledWindow widget. Also new are two drawing modes. One allows for intermediate drawing, primarily to support compositing. The other is alpha drawing using cairo's paint_with_alpha() methods. Support for rounded rectangles is also added.