rustyfi-html 0.1.2

//! The reflow document's base stylesheet (Slice 1: "Base document CSS (max-width
//! column, line-height, font stack, dark/light neutral)"). Everything here is
//! FLOW layout — no `position: absolute`/`top`/`left` anywhere (the defining
//! difference from `crate::render_html_fixed`'s faithful `.page`/`.run` rules,
//! which position every run at its exact placed coordinate).
//!
//! S4 adds `ul.list`/`ol.list` spacing rules for the real
//! `<ul>`/`<ol>`/`<li>` `block.rs`'s `VertBox::ListMark` arm now emits —
//! bullet/number glyphs and basic indentation are otherwise the browser's
//! own UA stylesheet default for `<ul>`/`<ol>`/`<li>`, so no additional
//! list-style rule is needed; `<em>`/`<strong>` (S4's other new tag pair)
//! likewise need no CSS of their own — the browser default (italic/bold) is
//! exactly the semantic they name.
//!
//! ## The body rule is computed, not fixed
//!
//! `body` carries the document's OWN dominant face and size
//! (`text::BodyStyle::dominant`). That is what lets `inline.rs` write the
//! bulk of the text as bare characters with no `<span>` at all, and lets the
//! runs that do differ state their size as an `em` ratio — so the reader
//! scales the whole document by changing one number rather than fighting a
//! per-run absolute point size.
//!
//! ## Why `.frame` has no border of its own
//!
//! A `FrameStart`/`FrameEnd` pair is `block-frame-breakable`, which real
//! packages use for section bodies, list items, figure wrappers and
//! quotation blocks as readily as for anything that actually has a rule
//! around it — the `enumitem` manual alone opens 336 of them. Drawing a box
//! around every one turned the page into nested rounded rectangles.
//!
//! What distinguishes them is the frame's own decoration, and that IS now
//! drawn: `fire_hooks` records each one box-local
//! (`DocumentValue::reflow_frame_decos`), and `structure::frame_decoration`
//! turns it into a `background` or a scalable `<svg>` under `.frame.framed`.
//! So a frame that draws nothing still draws nothing, and one that draws a
//! title box keeps it.

use std::fmt::Write as _;

use rustyfi_backend::PageGeometry;

use super::Ctx;

/// `geometry.text_width` seeds the reading column's `max-width` (in `pt`,
/// SATySFi's own unit, 1:1 with CSS `pt`) — a nod to the source document's
/// own measure without pinning the layout to it: a narrow viewport still
/// shrinks the column further (the `max-width`/`width:100%` combination),
/// and nothing here prevents the column from being narrower than the
/// viewport on a wide screen either. Purely a readability default, not a
/// geometry replay.
pub(crate) fn stylesheet(geometry: &PageGeometry, ctx: &Ctx) -> String {
    let max_width = geometry.text_width.0.max(1.0);
    let body_size = ctx.body.size;
    // The document's own dominant face, when one is known — already a full
    // stack ending in a generic (`fonts::reflow_font_stack`), so body text
    // renders in the face it was typeset in where the reader has it and in
    // something sensible where they do not, and `inline.rs` need not repeat
    // it on every run.
    let body_family = ctx
        .body
        .font
        .and_then(|f| ctx.font_family_for(f))
        .unwrap_or_else(|| "Georgia, \"Noto Serif\", \"Noto Serif CJK JP\", serif".to_string());
    format!(
        "\
body {{\n\
  margin: 0;\n\
  padding: 2rem 1rem;\n\
  font-family: {body_family};\n\
  font-size: {body_size}pt;\n\
  line-height: 1.7;\n\
  background: #fff;\n\
  color: #1a1a1a;\n\
}}\n\
.doc {{\n\
  max-width: {max_width}pt;\n\
  width: 100%;\n\
  margin: 0 auto;\n\
  box-sizing: border-box;\n\
}}\n\
.para {{\n\
  margin: 0 0 0.9em 0;\n\
  text-align: justify;\n\
  hyphens: auto;\n\
  overflow-wrap: break-word;\n\
}}\n\
.para[data-align=\"center\"] {{ text-align: center; }}\n\
.para[data-align=\"right\"] {{ text-align: right; }}\n\
.frame {{ margin: 0.6em 0; }}\n\
/* A frame that DREW something: the drawing is a sibling SVG stretched\n\
   over the whole box, so the box has to be its containing block.\n\
   No padding of its own: the frame's left padding is already folded into\n\
   the contained lines' own offsets (`indent_left`) and its vertical ones\n\
   arrive as `FramePad` skips, so adding CSS padding here would double all\n\
   three. Only `padding-right`, which nothing else records, is written — per\n\
   frame, from its real value. */\n\
.frame.framed {{ position: relative; }}\n\
/* Content sits ABOVE the drawing. `:not(.frame-deco)` is load-bearing:\n\
   `.frame.framed > *` outranks `svg.frame-deco` on specificity, so without\n\
   it the decoration is pulled into normal flow and every framed block\n\
   renders as an empty box with its content underneath. */\n\
.frame.framed > *:not(.frame-deco) {{ position: relative; }}\n\
.frame.framed > svg.frame-deco {{\n\
  position: absolute;\n\
  left: 0;\n\
  top: 0;\n\
  width: 100%;\n\
  height: 100%;\n\
  overflow: visible;\n\
  pointer-events: none;\n\
}}\n\
.embed {{ margin: 0.5em 0; }}\n\
.iframe {{ display: inline; }}\n\
.hskip {{ display: inline-block; }}\n\
.clearpage {{\n\
  border: none;\n\
  border-top: 1px dashed rgba(127,127,127,0.5);\n\
  margin: 2em 0;\n\
}}\n\
.reflow-empty {{ font-style: italic; opacity: 0.7; }}\n\
.gfx-placeholder, .pdf-image {{\n\
  display: inline-block;\n\
  vertical-align: middle;\n\
  border: 1px dashed rgba(127,127,127,0.5);\n\
  border-radius: 3px;\n\
}}\n\
.img {{\n\
  max-width: 100%;\n\
  height: auto;\n\
  vertical-align: middle;\n\
}}\n\
span.img {{\n\
  display: inline-block;\n\
  background-repeat: no-repeat;\n\
  background-size: contain;\n\
  background-position: center;\n\
}}\n\
a.link {{ color: #1a5fb4; text-decoration: underline; }}\n\
.heading {{\n\
  margin: 1.4em 0 0.5em 0;\n\
  font-weight: bold;\n\
  line-height: 1.3;\n\
  text-align: left;\n\
  /* The heading's SIZE is the document's own, carried by the run inside\n\
     it as an em ratio of the body. Without this the UA default for\n\
     h1..h6 (2em, 1.5em, ...) multiplies that ratio and a 1.83em section\n\
     title renders at 3.7em. */\n\
  font-size: inherit;\n\
}}\n\
table.tabular {{\n\
  border-collapse: collapse;\n\
  margin: 1em auto;\n\
  max-width: 100%;\n\
}}\n\
/* No border here: which grid lines a table draws is the DOCUMENT's, read\n\
   off `TabularBox::rules` and written per cell (`structure.rs`'s `Borders`).\n\
   A blanket rule turned every booktabs-style table into a full grid.\n\
   No padding either — the cell's own margins arrive as real `hskip` struts\n\
   inside it, so a CSS pad would be added on top of them. */\n\
table.tabular td {{\n\
  padding: 0.15em 0;\n\
  vertical-align: baseline;\n\
}}\n\
/* Fixed-pitch text: upstream's line breaks are the author's and survive as\n\
   a hard break, so justification and hyphenation must not fight them. */\n\
.para.code {{\n\
  text-align: left;\n\
  hyphens: none;\n\
  overflow-x: auto;\n\
}}\n\
ul.list, ol.list {{\n\
  margin: 0 0 1em 0;\n\
  padding: 0 0 0 1.5em;\n\
}}\n\
ul.list ul.list, ul.list ol.list, ol.list ul.list, ol.list ol.list {{\n\
  margin: 0.2em 0;\n\
}}\n\
ul.list li, ol.list li {{ margin: 0.2em 0; }}\n\
/* The in-text footnote anchor is a zero-width link TARGET only — the\n\
   document typesets its own reference marker. */\n\
.fnref {{ display: inline; }}\n\
aside.footnote {{\n\
  margin: 0.6em 0 1.2em 0;\n\
  padding: 0.2em 0 0.2em 1em;\n\
  border-left: 3px solid rgba(127,127,127,0.35);\n\
  font-size: 0.92em;\n\
}}\n\
aside.footnote .fnback {{\n\
  margin-left: 0.4em;\n\
  text-decoration: none;\n\
  color: inherit;\n\
  opacity: 0.55;\n\
}}\n\
aside.footnote .para {{ margin: 0; text-align: left; }}\n\
aside.footnote .para + .para {{ margin-top: 0.3em; }}\n\
"
    )
}

/// One `background-image` rule per image the flow placed more than once
/// (`Ctx::shared_images`, filled during the body walk — so this must be
/// called AFTER it, exactly like `fonts::font_face_rules`). Each image's
/// bytes appear once here instead of once per placement; see `inline.rs`'s
/// `Image` arm for why that matters and what it costs.
pub(crate) fn shared_image_rules(ctx: &Ctx) -> String {
    let mut out = String::new();
    for id in ctx.shared_images.borrow().iter() {
        if let Some(res) = ctx.images.get(*id) {
            let _ = write!(
                out,
                ".shared-img-{id} {{ background-image: url(\"{}\"); }}\n",
                crate::image::data_uri(res),
            );
        }
    }
    out
}