Blog

Sixel Graphics

May 4, 2021
graphics

Reading time: 1 minutes and 7 seconds. What are Sixels? VT330/VT340 Programmer Reference Manual, Ch. 14 Sixel Graphics. Escape Character DCS (Device Control String): 0x90 OR ESC+P: 0x1B + 0x50 Termination ST (String Terminator) 0x0 OR ESC+\: 0x1B + 0x5C Control Functions LSB (least-significant bit) at the top. >>> 0x90 0x40 = 0x90 0b000001 ■ □ □ □ □ □ >>> 0x90 0x74 = 0x90 0b110100 ■ □ ■ □ ■ ■ >>> sixel2str = lambda i : '\n'. ...

On Signed Distance Functions

Aug 11, 2020
SDF, mathematics

Reading time: 12 minutes and 41 seconds. Introduction Formal Definition In more rigorous terms, signed distance functions (aka SDFs) are defined as functions that satisfy a particular form of the eikonal equation1. The general eikonal equation is of the form: $$||\nabla u(x)|| = \frac{1}{f(x)},\quad x \in \Omega,$$ where \(\Omega\) is an open set in \(\mathbb{R}^n\), and \(f(x) : \mathbb{R}^n \to \mathbb{R}\) is a function with positive values. In physical terms, the solution \(u(x)\) to this nonlinear partial differential equation can be interpreted as the shortest time needed to travel from the boundary \(\partial\Omega\) to \(x \in \Omega\), with \(f(x)\) being the speed at \(x\). ...

3