crates/veilvoice-video/src/font.rs

A monospace face, five pixels by seven, drawn here.

Why this exists rather than a font file

crate::frames draws the video's pictures as actual pixels, and names are text. Text needs a face and a rasteriser, and the two usual ways to get those are both wrong for this project.

Loading one of the system's fonts makes the output depend on which machine drew it: the same recording rendered on two computers would produce different files, and this project publishes reproducible builds and checks them. Pulling in a font rasteriser means a large dependency to draw eight names, in a program whose front page invites the reader to run cargo tree and find nothing large.

So the face is here, it is ninety-five glyphs, and it is the same everywhere.

What it can and cannot draw

Printable ASCII, from space to ~. Anything else is drawn as an open box, which is the honest way to render a character this cannot: a name in Cyrillic or Japanese comes out as boxes rather than as nothing, and crate::frames says so in its notes rather than letting somebody find out by watching the finished video.

The preview page does not have this limit, because it is markup and uses whatever the reader's machine has. That is a real difference between the two outputs and it is written down rather than glossed over.

Five by seven

Small enough to write out and check by eye, large enough to stay legible when scaled up by whole numbers, which is the only way it is ever scaled: a bitmap glyph drawn at a fractional size is a blurred glyph, so Face::scale_for picks a whole-number multiple and the text is crisp at any frame size.

In plain words

The letters used in the video, drawn dot by dot inside this program.

It is here rather than taken from the computer so that the same recording makes the same video on every machine, and so that this program does not have to carry a large piece of somebody else's code to write eight names.

WHAT THIS FILE CONTAINS

418 lines defining 4 functions (4 public), 0 types and 7 constants. Everything below is read out of the source, so it cannot disagree with the code.

What happens when it runs. These are the ways in: public, and nothing else in this file calls them, so they are what an outside caller reaches first.

• can_draw line 286 · Whether every character in text can be drawn.
  reaches glyph
• scale_for line 310 · The largest whole-number scale at which text fits inside room pixels.
  reaches width_of

WHAT CALLS WHAT

The functions this file defines, and the calls between them. An edge means the callee's name appears, called, inside the caller's body. This is a syntactic reading, not a type-resolved one.

%%{init: {"theme":"base","themeVariables":{"background":"#1a1b26","primaryColor":"#1f2335","primaryTextColor":"#c0caf5","primaryBorderColor":"#7aa2f7","secondaryColor":"#16161e","tertiaryColor":"#16161e","lineColor":"#737aa2","textColor":"#c0caf5","mainBkg":"#1f2335","nodeBorder":"#7aa2f7","clusterBkg":"#16161e","clusterBorder":"#2f3549","fontFamily":"ui-monospace, SFMono-Regular, Consolas, monospace","fontSize":"14px"}}}%%
flowchart TD
    n_glyph["glyph<br/>line 274"]
    n_can_draw(["can_draw<br/>line 286"])
    n_width_of["width_of<br/>line 291"]
    n_scale_for(["scale_for<br/>line 310"])
    n_can_draw --> n_glyph
    n_scale_for --> n_width_of
    click n_glyph href "https://github.com/tilas01/veilvoice/blob/main/crates/veilvoice-video/src/font.rs#L274" "open the source"
    click n_can_draw href "https://github.com/tilas01/veilvoice/blob/main/crates/veilvoice-video/src/font.rs#L286" "open the source"
    click n_width_of href "https://github.com/tilas01/veilvoice/blob/main/crates/veilvoice-video/src/font.rs#L291" "open the source"
    click n_scale_for href "https://github.com/tilas01/veilvoice/blob/main/crates/veilvoice-video/src/font.rs#L310" "open the source"
    classDef entry fill:#1f2335,stroke:#7aa2f7,color:#c0caf5
    class n_can_draw,n_scale_for entry
    classDef api fill:#1f2335,stroke:#7dcfff,color:#c0caf5
    class n_glyph,n_width_of api

ITEMS