[wish] On-screen markers to aid drawing

Can you explain a bit more what all of those features mean? Maybe post a screenshot where you show what its about (I doubt many developers are familiar with CorelDraw).

When you're drawing in CorelDraw, you get dynamic guides showing you where the mouse pointer is, with a slight localised snap-to effect. It mainly works on the outlines of a shape, so if your mouse is on the edge of a square, a little blue marker comes up saying 'Edge'. As you come to the corner, the marker changes to 'Node'. As you reach the midpoint of the side of the square, it changes to 'Midpoint'.

When you get to the exact center of a shape, the guide says 'Centre', so if you want a circle in a square, for example, you click on the previously-created circle, and drag from the circle's 'Centre' mark to the square's. Job done. All perfectly aligned.

For circles and ellipses, there's 'Quadrant' (top, bottom, left, right of the circle) and 'Tangent' (90º from the edge of the circle to the centre).

When drawing lines, there's 'Perpendicular', when you're at 90º to the line/edge you're drawing to.

A (probably incomplete) list:

Quadrant
Tangent
Perpendicular
Centre
Midpoint
Edge
Node
Intersection

Is doesn't sound that impressive as I describe it, but it's absolutely invaluable when you're drawing, and saves -for example- having to measure the size of a square to find the *exact* midpoint. It saves a huge amount of mathmatical messing around when drawing complex designs and makes the whole process considerably faster.

Oops, sorry. 'Tangent' is 90º to the circumference of the circle or ellipse. See why I prefer to avoid the maths?

The requested feature is similar to object snap mode known well by users of Autocad. The fundamental conception of snapping is well described on the following page: http://www.cadtutor.net/acad/acad2ki/osnap/osnap.html

These features are being developed in trunk version so I mark this report as a "In progress"

Closing - on-canvas snap indicators for available snap targets had been implemented in Inkscape 0.47:
http://wiki.inkscape.org/wiki/index.php/Release_notes/0.47#Snapping
… and continue to be improved in each new release (0.91 will support tangential and perpendicular snapping).

The request for dynamic guides are tracked separately (bug #171006).