Appearance

Appearance controls how a visible signature is drawn: which content shows (text, graphics, or both), their layout, colours, fonts, and the Acro6 validity-icon overlay. It is built fluently; sensible defaults reproduce the classic text appearance. Appearance is #[non_exhaustive] — construct it through Appearance::new() / Appearance::default() / Appearance::invisible(), then chain the builder methods below.

use mudrit_pdfsign::{Appearance, Image, Layout, RenderMode};

// logo on the left, signer text on the right, with the viewer validity icon
let ap = Appearance::new()
    .mode(RenderMode::GraphicAndText)
    .layout(Layout::GraphicLeft)
    .graphic(Image::Png(std::fs::read("logo.png")?));

Appearance fields

Appearance builder methods

Validation rules

Appearance::validate() (called automatically by sign_pdf) rejects:

• more than 4 graphics
• graphic_fraction outside 0.1..=0.9
• watermark_opacity outside 0.0..=1.0
• a font_size that is not finite and > 0.0
• a line_spacing that is not finite and > 0.0
• a border.width that is not finite and > 0.0
• a template using a complex/RTL script (Hebrew, Arabic, the Indic block, Thai/Lao/Tibetan/Myanmar/Khmer, …) with no font set — Helvetica (WinAnsi) cannot shape those glyphs
• RenderMode::Invisible combined with trust_icon: true or any graphics — use Appearance::invisible() instead
• RenderMode::Watermark combined with trust_icon: true, or with zero graphics (needs exactly one background graphic)
• RenderMode::GraphicOnly / RenderMode::GraphicAndText with zero graphics

RenderMode

Which of the text block and the graphics are drawn, and how.

Layout

Where the graphic sits relative to the text block in RenderMode::GraphicAndText.

Direction

Base paragraph direction for the appearance text block (Unicode bidi, UAX #9).

SigField

A field shown in the signer text block, in the order listed (used with Appearance::fields). Empty values are skipped (e.g. an absent organisation).

Labels

Localizable labels for the signer text block. Override any to translate — used when Appearance::fields is set.

Each field also has a same-named fluent setter (Labels::default().signed_by("Hastakshar:"), …).

Std14

A PDF standard-14 (built-in, non-embedded) text font — the three Adobe base families in their four styles. Renders in every PDF viewer without embedding a font program, but covers only WinAnsi (Latin-1). For Unicode text set an embedded Appearance::font instead, which overrides this choice.

Default: Std14::Helvetica (the classic signer-block font).

Border

A border stroked around the signature box (drawn inside the signed appearance, so it renders in every viewer).

Attach with Appearance::border(Border::solid([0.0, 0.0, 0.0], 0.75)).

FontSource

Where the Unicode appearance font comes from. Constructed via Appearance::font (bytes) or Appearance::font_path (path); not built directly.

FontSource::read(&self) -> Result<Vec<u8>> resolves to the font bytes, reading the file for Path. Its Debug impl never prints the raw bytes — only the kind and length/path.

Image

A raster image to embed in a signature appearance (logo, handwritten signature, …). Image is #[non_exhaustive].

Appearance::new()
    .mode(RenderMode::GraphicAndText)
    .graphic(Image::Path("logo.png".into())); // format auto-detected at sign time

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