craft-drawingml: the theme model (#940)

* Add craft-drawingml: units, colours, preset shapes, custom geometry and text warps The parts of DrawingML that need no document model, moved from DeckCraft (60f91f78): crates/color, crates/geom (preset, warp, Xfrm and the EMU conversions) and crates/pptx/src/custgeom.rs with CustomPath from crates/model. The code is unchanged except that custgeom reads craft-xml trees and writes to a craft-xml Writer instead of DeckCraft's own XML helper, and matches elements by local name. The 59 tests of the moved code come with it; six more cover the custom geometry limits. * drawingml: evaluate a custom geometry's guide lists once per coordinate space read_cust_geom rebuilt Guides and evaluated avLst and gdLst again for every path: up to 1,000 paths times up to 10,000 guides, each name copied and hashed. Guides are now cached per path coordinate space (w, h). At most 16 spaces and 4 MiB of guide names are kept per geometry; paths in further spaces are left out. The first space is always kept, and a geometry without guides is not capped. Ported from storytold/deckcraft#1789. A list counts as having guides only when it has gd children, as that PR's review asked. * drawingml: the model types for fills, lines, text, tables, charts and diagrams Moved from DeckCraft (60f91f78) crates/model/src: style.rs, text.rs, table.rs, chart.rs, numfmt.rs and trendline.rs, plus Diagram, DiagramNode and the MediaId and SlideId newtypes from lib.rs. The files are unchanged except that deckcraft_color:: is crate::color:: and Fill and TableBorder allow clippy::large_enum_variant. Their 60 tests come with them. Readers and writers follow. * drawingml: the theme model (colour, font and format schemes) Moved from DeckCraft crates/model/src/theme.rs at 60f91f78: FontSet, ScriptFont, FontScheme, FormatScheme, Theme and default_format. The app's theme gallery, its variants and its own default theme stay in the app. Theme::default() is a plain theme built in place, so nothing here depends on a gallery.
2026-11-12 07:46:08 +00:00 · 2026-11-11 19:22:03 -05:00
parent e0a3b2b8c4
commit 8079878ae2
2 changed files with 185 additions and 1 deletions
@@ -11,7 +11,7 @@
 //! - [`warp`]: preset text warps (`a:prstTxWarp`).
 //! - The model, without readers and writers yet: [`style`] (colour references, fills, lines,
 //!   effects), [`text`] (text bodies, paragraphs, runs), [`table`], [`chart`] with [`numfmt`]
-//!   (number format codes) and [`diagram`] (SmartArt outlines). Media are named by [`MediaId`];
+//!   (number format codes), [`theme`] (colour, font and format schemes) and [`diagram`] (SmartArt outlines). Media are named by [`MediaId`];
 //!   the bytes stay with the caller.
 //!
 //! Nothing here opens a package: readers take a [`craft_xml::El`] and writers a
@@ -27,6 +27,7 @@ pub mod preset;
 pub mod style;
 pub mod table;
 pub mod text;
+pub mod theme;
 mod trendline;
 pub mod warp;

@@ -0,0 +1,183 @@
+//! Themes: colour scheme, font scheme and format scheme (the fill/line/effect "style matrix").
+
+use crate::color::{ColorScheme, ColorTransform, Rgba, SchemeSlot};
+use serde::{Deserialize, Serialize};
+
+use crate::style::{ColorRef, Effects, Fill, Gradient, GradientShape, GradientStop, Line, Shadow};
+
+#[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize)]
+#[serde(default, rename_all = "camelCase")]
+pub struct FontSet {
+    pub latin: String,
+    pub ea: String,
+    pub cs: String,
+    /// Per-script typefaces (`a:font script="Arab" typeface="…"`), in document order.
+    #[serde(skip_serializing_if = "Vec::is_empty")]
+    pub scripts: Vec<ScriptFont>,
+}
+
+/// A theme font for one script (ISO 15924 tag, e.g. `Arab`).
+#[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize)]
+#[serde(default, rename_all = "camelCase")]
+pub struct ScriptFont {
+    pub script: String,
+    pub typeface: String,
+}
+
+impl FontSet {
+    /// The typeface the theme gives `script` (`"Arab"`), if any.
+    pub fn script(&self, script: &str) -> Option<&str> {
+        self.scripts.iter().find(|f| f.script.eq_ignore_ascii_case(script) && !f.typeface.is_empty()).map(|f| f.typeface.as_str())
+    }
+}
+
+#[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize)]
+#[serde(default, rename_all = "camelCase")]
+pub struct FontScheme {
+    pub name: String,
+    /// Headings.
+    pub major: FontSet,
+    /// Body.
+    pub minor: FontSet,
+}
+
+#[derive(Clone, Debug, Default, PartialEq, Serialize, Deserialize)]
+#[serde(default, rename_all = "camelCase")]
+pub struct FormatScheme {
+    pub name: String,
+    /// Subtle, moderate, intense (style index 1–3).
+    pub fills: Vec<Fill>,
+    pub lines: Vec<Line>,
+    pub effects: Vec<Effects>,
+    /// Background fills (index 1001–1003).
+    pub bg_fills: Vec<Fill>,
+}
+
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(default, rename_all = "camelCase")]
+pub struct Theme {
+    pub name: String,
+    pub colors: ColorScheme,
+    pub fonts: FontScheme,
+    pub format: FormatScheme,
+    /// Raw theme XML extras kept for round-trip (object defaults, extra colour lists).
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub raw_extra: Option<String>,
+}
+
+impl Default for Theme {
+    /// A plain theme: black and white, a slate and a warm grey, six accents, no font names (the
+    /// writer puts `Arial` where a Latin face is required) and [`default_format`].
+    fn default() -> Self {
+        let hex = |s: &str| Rgba::from_hex(s).unwrap_or(Rgba::BLACK);
+        let colors = ["000000", "FFFFFF", "1E2B3C", "EDEBE7", "2E6FD8", "F26B1D", "2EA36F", "8A5CD8", "D83F6B", "E3B21C", "2E6FD8", "7A5BA6"];
+        Theme {
+            name: "Theme".into(),
+            colors: ColorScheme { name: "Default".into(), colors: colors.map(hex) },
+            fonts: FontScheme::default(),
+            format: default_format(),
+            raw_extra: None,
+        }
+    }
+}
+
+impl Theme {
+    /// Resolve a theme font reference (`+mj-lt`, `+mn-ea`…) to a family name.
+    pub fn font(&self, name: &str) -> String {
+        match name {
+            "+mj-lt" => self.fonts.major.latin.clone(),
+            "+mn-lt" => self.fonts.minor.latin.clone(),
+            "+mj-ea" => self.fonts.major.ea.clone(),
+            "+mn-ea" => self.fonts.minor.ea.clone(),
+            "+mj-cs" => self.fonts.major.cs.clone(),
+            "+mn-cs" => self.fonts.minor.cs.clone(),
+            other => other.to_string(),
+        }
+    }
+}
+
+fn ph() -> ColorRef {
+    ColorRef::scheme(SchemeSlot::PhClr)
+}
+
+/// The format scheme used where a theme has none, and to fill a short style list: flat solid fills, a soft gradient, and a gentle shadow for "intense".
+pub fn default_format() -> FormatScheme {
+    let grad = |a: i32, b: i32| {
+        Fill::Gradient(Gradient {
+            tile: [0.0; 4],
+            stops: vec![
+                GradientStop { pos: 0.0, color: ph().with(ColorTransform::LumMod(a)).with(ColorTransform::SatMod(103000)) },
+                GradientStop { pos: 1.0, color: ph().with(ColorTransform::LumMod(b)) },
+            ],
+            shape: GradientShape::Linear { angle: 90.0, scaled: false },
+            rotate_with_shape: true,
+            flip: None,
+        })
+    };
+    FormatScheme {
+        name: "Default".into(),
+        fills: vec![Fill::solid(ph()), grad(110000, 92000), grad(105000, 80000)],
+        lines: vec![Line::solid(ph(), 0.75), Line::solid(ph(), 1.0), Line::solid(ph(), 1.5)],
+        effects: vec![
+            Effects::default(),
+            Effects::default(),
+            Effects {
+                outer_shadow: Some(Shadow {
+                    color: ColorRef::rgb(Rgba::BLACK).with(ColorTransform::Alpha(40000)),
+                    blur: 6.0,
+                    dist: 3.0,
+                    dir: 90.0,
+                    inner: false,
+                    sx: 1.0,
+                    sy: 1.0,
+                    kx: 0.0,
+                    ky: 0.0,
+                    align: "t".into(),
+                    rotate_with_shape: false,
+                }),
+                ..Default::default()
+            },
+        ],
+        bg_fills: vec![
+            Fill::solid(ph()),
+            Fill::solid(ph().with(ColorTransform::Tint(95000)).with(ColorTransform::SatMod(170000))),
+            grad(102000, 85000),
+        ],
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn the_default_theme_has_a_full_style_matrix_and_no_font_names() {
+        let t = Theme::default();
+        assert_eq!((t.format.fills.len(), t.format.lines.len(), t.format.effects.len(), t.format.bg_fills.len()), (3, 3, 3, 3));
+        assert_eq!(t.colors.get(SchemeSlot::Lt1), Rgba::WHITE);
+        assert_eq!(t.fonts, FontScheme::default());
+    }
+
+    #[test]
+    fn theme_font_references_resolve_and_other_names_pass_through() {
+        let mut t = Theme::default();
+        t.fonts.major.latin = "Head".into();
+        t.fonts.minor.cs = "Body CS".into();
+        t.fonts.minor.scripts.push(ScriptFont { script: "Arab".into(), typeface: "Naskh".into() });
+        assert_eq!(t.font("+mj-lt"), "Head");
+        assert_eq!(t.font("+mn-cs"), "Body CS");
+        assert_eq!(t.font("Georgia"), "Georgia");
+        assert_eq!(t.fonts.minor.script("arab"), Some("Naskh"));
+        assert_eq!(t.fonts.minor.script("Hebr"), None);
+    }
+
+    #[test]
+    fn a_theme_survives_json_and_missing_fields_take_the_default() {
+        let t = Theme::default();
+        let json = serde_json::to_string(&t).unwrap();
+        assert_eq!(serde_json::from_str::<Theme>(&json).unwrap(), t);
+        let partial: Theme = serde_json::from_str(r#"{"name":"X"}"#).unwrap();
+        assert_eq!(partial.colors, t.colors);
+        assert_eq!(partial.name, "X");
+    }
+}