Spiral splines in typeface design A case study of Manjari Malayalam typeface Hello & Welcome. I am Kavya, he is santhosh. We are going to discuss the use of Spiral spline curves in the design of typefaces, with Manjari - Malayalam typeface as an example. Santhosh did the design part and we together did the opentype engineering. Santhosh Thottingal & Kavya Manohar Swathanthra Malayalam Computing

This is a sample of Manjari typeface in 3 variants This is a sample of Manjari typeface in 3 variants. It reads Manjari in Malayalam. Manjari has three variants - Bold, Regular and Thin. The curves in Manjari follow a spiral shaped path between its control points.. The terminals are also rounded, giving a very soft feeling for the eyes.

Here is another sample. Contemporary style of Malayalam script is characterised by loops and curly strokes. Manjari follows this trend. But this was not the case during the early days of script evolution.

Vattezhuthu - Tharisappalli Copper plate 849 AD -9th centuary Vattezhuthu - Tharisappalli Copper plate 849 AD -9th centuary. They were rather elongated curves or slightly rectangular.

1772 Cleamant Pianius. The first printed book in Malayalam using movable types- Samkshepavedartham uses rectangular types.

1829 - New testament - Benchamin Bailey - start of rounded types

Modern printing. 2018. Still rounded.

A good handwriting is when it is “rounded” Manjari takes up this roundeness characteristics to the next level of perfection using spiral curve segments.

Optimal Curve What defines an optimal rounded curve between two control points, especially in type design?

From spiral to splines - Optimal Techniques in interactive curve design Ralph Linus Levien The answer was sought by Ralph Linus Levien on his thesis

Disjoing curves. No continuity In typedesign curves are interpolated from control points. How smooth can be the joining of two different curve segments? Let us see In what all different ways can two curve segments join together. This is a set of disjoint curves. Disjoing curves. No continuity

G0 continuous curves. Continuous with abrupt transition G0, continous, but not smooth. Has an abrupt transition. G0 continuous curves. Continuous with abrupt transition

G1 continuous curves has common tangent Here the join point is smoother with the tangents on either side of the curves being essentially the same. Call it G1 continuity. G1 continuous curves has common tangent

G2 continuous curves has common center of curvature The joining can be still more smooth, if it has a common centre of curvature at the joint points. This is G2 continuous joining of curve points. G2 continuous curves has common center of curvature

in a two parameter, G2 continuous interpolating spiral spline Every curve segment in a two parameter, G2 continuous interpolating spiral spline can be cut from an Euler spiral G2 continuous interpolating spiral spline between adjacent control points can be cut from an Euler spiral subjecting to rotation, scaling, translation and mirror image transformations. He calls Euler spiral as the generating curve for spiral splines.

G2 continuous interpolating spiral spline between adjacent control points can be cut from an Euler spiral subjecting to rotation, scaling, translation and mirror image transformations}. He calls Euler spiral as the generating curve for spiral splines.

Spiral Spline Every curve segment in the glyph is a segment from Euler spiral G2 continuous interpolating spiral spline between adjacent control points can be cut from an Euler spiral subjecting to rotation, scaling, translation and mirror image transformations. He calls Euler spiral as the generating curve for spiral splines.

Design Process

Inkscape & Fontforge

Popularity

Manjari: github.com/smc/manjari