Fix feature flag matrix

Author: fschutt

layout/Cargo.toml

@@ -69,8 +69,11 @@ widgets = ["text_layout", "dep:strfmt"]
 extra = ["dep:tfd"]
 
 # Basic text shaping (unicode support, allsorts font parsing)
+# Requires font_loading for font discovery (FcFontCache)
 # Does NOT include hyphenation (saves ~25 dependencies)
 text_layout = [
+    "std",
+    "font_loading",
     "dep:unicode-normalization",
     "dep:allsorts",
     "dep:tinyvec",

layout/src/font_traits.rs

@@ -5,9 +5,9 @@
 
 use azul_core::geom::LogicalSize;
 
-#[cfg(feature = "text_layout")]
+#[cfg(all(feature = "text_layout", feature = "font_loading"))]
 pub use crate::text3::script::Language;
-#[cfg(feature = "text_layout")]
+#[cfg(all(feature = "text_layout", feature = "font_loading"))]
 pub use crate::text3::{
     cache::{
         AvailableSpace, BidiDirection, ContentIndex, FontHash, FontManager, FontSelector,
@@ -19,8 +19,12 @@ pub use crate::text3::{
     script::Script,
 };
 
+#[cfg(all(feature = "text_layout", feature = "font_loading"))]
 pub type TextLayoutCache = LayoutCache;
 
+#[cfg(not(all(feature = "text_layout", feature = "font_loading")))]
+pub use stub::TextLayoutCache;
+
 /// Trait for types that support cheap, shallow cloning (e.g., reference-counted types).
 pub trait ShallowClone {
     /// Create a shallow clone (increment reference count, don't copy data)
@@ -67,11 +71,42 @@ pub trait FontLoaderTrait<T>: Send + core::fmt::Debug {
     fn load_font(&self, font_bytes: &[u8], font_index: usize) -> Result<T, LayoutError>;
 }
 
-// When text_layout is disabled, provide minimal stub types
-#[cfg(not(feature = "text_layout"))]
+/// Opaque font identifier - wraps the underlying font system's ID type
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
+pub struct FontId(pub u64);
+
+/// Trait for font system abstraction (font discovery, fallback chains).
+///
+/// This abstracts over the underlying font system (e.g., rust_fontconfig, fontdb)
+/// allowing text3 to work with or without system font discovery.
+pub trait FontSystemTrait: Send + Sync {
+    /// The type of font fallback chain this system uses
+    type FallbackChain: FontFallbackChainTrait;
+
+    /// Resolve a character to a font ID using the fallback chain
+    fn resolve_char(&self, chain: &Self::FallbackChain, c: char) -> Option<FontId>;
+
+    /// Get the font data (bytes) for a font ID
+    fn get_font_data(&self, font_id: FontId) -> Option<alloc::vec::Vec<u8>>;
+
+    /// Get the font index within the font file
+    fn get_font_index(&self, font_id: FontId) -> usize;
+}
+
+/// Trait for font fallback chains
+pub trait FontFallbackChainTrait: Clone + Send + Sync {
+    /// Check if the chain is empty
+    fn is_empty(&self) -> bool;
+
+    /// Get the primary font ID (if any)
+    fn primary_font_id(&self) -> Option<FontId>;
+}
+
+// When text_layout or font_loading is disabled, provide minimal stub types
+#[cfg(not(all(feature = "text_layout", feature = "font_loading")))]
 pub use stub::*;
 
-#[cfg(not(feature = "text_layout"))]
+#[cfg(not(all(feature = "text_layout", feature = "font_loading")))]
 mod stub {
     use super::*;
 
@@ -94,13 +129,18 @@ mod stub {
         RightToLeft,
     }
 
+    /// Stub for BidiDirection when text_layout is disabled
+    #[derive(Debug, Clone, Copy, PartialEq, Eq)]
+    pub enum BidiDirection {
+        Ltr,
+        Rtl,
+    }
+
     #[derive(Debug, Clone)]
     pub struct StyleProperties;
 
     #[derive(Debug, Clone)]
-    pub struct Glyph<T> {
-        _phantom: core::marker::PhantomData<T>,
-    }
+    pub struct Glyph;
 
     #[derive(Debug, Clone, Copy)]
     pub struct VerticalMetrics {
@@ -124,14 +164,10 @@ mod stub {
     pub struct FontSelector;
 
     #[derive(Debug)]
-    pub struct FontManager<T, Q> {
-        _phantom: core::marker::PhantomData<(T, Q)>,
-    }
+    pub struct FontManager;
 
     #[derive(Debug)]
-    pub struct LayoutCache<T> {
-        _phantom: core::marker::PhantomData<T>,
-    }
+    pub struct LayoutCache;
 
     // Additional stub types needed by solver3
     pub type ContentIndex = usize;
@@ -186,7 +222,7 @@ mod stub {
     #[derive(Debug, Clone)]
     pub struct UnifiedLayout;
 
-    pub type TextLayoutCache = LayoutCache<()>;
+    pub type TextLayoutCache = LayoutCache;
 
     pub type Size = azul_core::geom::LogicalSize;
 }

layout/src/fragmentation.rs

@@ -31,8 +31,20 @@ use azul_css::props::layout::fragmentation::{
     BoxDecorationBreak, BreakInside, Orphans, PageBreak, Widows,
 };
 
+#[cfg(all(feature = "text_layout", feature = "font_loading"))]
 use crate::solver3::display_list::{DisplayList, DisplayListItem};
 
+// Stub types when text_layout or font_loading is disabled
+#[cfg(not(all(feature = "text_layout", feature = "font_loading")))]
+#[derive(Debug, Clone, Default)]
+pub struct DisplayList {
+    pub items: Vec<DisplayListItem>,
+}
+
+#[cfg(not(all(feature = "text_layout", feature = "font_loading")))]
+#[derive(Debug, Clone)]
+pub struct DisplayListItem;
+
 // Page Templates (Headers, Footers, Running Content)
 
 /// Counter that tracks page numbers and other running content

layout/src/lib.rs

@@ -15,6 +15,7 @@ pub mod font_traits;
 pub mod image;
 #[cfg(feature = "text_layout")]
 pub mod managers;
+#[cfg(feature = "text_layout")]
 pub mod solver3;
 
 // Widget modules (behind feature flags)
@@ -35,12 +36,12 @@ pub mod callbacks;
 pub mod cpurender;
 #[cfg(feature = "text_layout")]
 pub mod event_determination;
-#[cfg(feature = "font_loading")]
+#[cfg(feature = "text_layout")]
 pub mod font;
 // Re-export allsorts types needed by printpdf
-#[cfg(feature = "font_loading")]
+#[cfg(feature = "text_layout")]
 pub use allsorts::subset::CmapTarget;
-#[cfg(feature = "font_loading")]
+#[cfg(feature = "text_layout")]
 pub use font::parsed::{
     FontParseWarning, FontParseWarningSeverity, FontType, OwnedGlyph, ParsedFont, PdfFontMetrics,
     SubsetFont,
@@ -113,7 +114,7 @@ pub fn parse_font_fn(
     .map(|parsed_font| parsed_font_to_font_ref(parsed_font))
 }
 
-#[cfg(feature = "font_loading")]
+#[cfg(feature = "text_layout")]
 pub fn parsed_font_to_font_ref(
     parsed_font: crate::font::parsed::ParsedFont,
 ) -> azul_css::props::basic::FontRef {
@@ -130,7 +131,7 @@ pub fn parsed_font_to_font_ref(
     azul_css::props::basic::FontRef::new(raw_ptr, parsed_font_destructor)
 }
 
-#[cfg(feature = "font_loading")]
+#[cfg(feature = "text_layout")]
 pub fn font_ref_to_parsed_font(
     font_ref: &azul_css::props::basic::FontRef,
 ) -> &crate::font::parsed::ParsedFont {

layout/src/paged.rs

@@ -15,8 +15,14 @@
 
 use azul_core::geom::{LogicalPosition, LogicalSize};
 
+#[cfg(all(feature = "text_layout", feature = "font_loading"))]
 use crate::solver3::display_list::DisplayList;
 
+// Stub type when text_layout or font_loading is disabled
+#[cfg(not(all(feature = "text_layout", feature = "font_loading")))]
+#[derive(Debug, Clone, Default)]
+pub struct DisplayList;
+
 /// Represents a series of containers that content flows into during layout.
 ///
 /// This is the core abstraction for fragmentation support. Different media types

layout/src/text3/cache.rs

@@ -21,14 +21,31 @@ use azul_css::{
     corety::LayoutDebugMessage, props::basic::ColorU, props::style::StyleBackgroundContent,
 };
 #[cfg(feature = "text_layout_hyphenation")]
-use hyphenation::{Hyphenator, Language, Load, Standard};
+use hyphenation::{Hyphenator, Language as HyphenationLanguage, Load, Standard};
 use rust_fontconfig::{FcFontCache, FcPattern, FcWeight, FontId, PatternMatch, UnicodeRange};
 use unicode_bidi::{BidiInfo, Level, TextSource};
 use unicode_segmentation::UnicodeSegmentation;
 
+// Stub type when hyphenation is disabled
 #[cfg(not(feature = "text_layout_hyphenation"))]
-use crate::text3::script::Language;
-use crate::text3::script::{script_to_language, Script};
+pub struct Standard;
+
+#[cfg(not(feature = "text_layout_hyphenation"))]
+impl Standard {
+    /// Stub hyphenate method that returns no breaks
+    pub fn hyphenate<'a>(&'a self, _word: &'a str) -> StubHyphenationBreaks {
+        StubHyphenationBreaks { breaks: Vec::new() }
+    }
+}
+
+/// Result of hyphenation (stub when feature is disabled)
+#[cfg(not(feature = "text_layout_hyphenation"))]
+pub struct StubHyphenationBreaks {
+    pub breaks: alloc::vec::Vec<usize>,
+}
+
+// Always import Language from script module
+use crate::text3::script::{script_to_language, Language, Script};
 
 /// Available space for layout, similar to Taffy's AvailableSpace.
 ///
@@ -6586,10 +6603,17 @@ fn polygon_line_intersection(
 // ADDITION: A helper function to get a hyphenator.
 /// Helper to get a hyphenator for a given language.
 /// TODO: In a real app, this would be cached.
-fn get_hyphenator(language: Language) -> Result<Standard, LayoutError> {
+#[cfg(feature = "text_layout_hyphenation")]
+fn get_hyphenator(language: HyphenationLanguage) -> Result<Standard, LayoutError> {
     Standard::from_embedded(language).map_err(|e| LayoutError::HyphenationError(e.to_string()))
 }
 
+/// Stub when hyphenation is disabled - always returns an error
+#[cfg(not(feature = "text_layout_hyphenation"))]
+fn get_hyphenator(_language: Language) -> Result<Standard, LayoutError> {
+    Err(LayoutError::HyphenationError("Hyphenation feature not enabled".to_string()))
+}
+
 fn is_break_opportunity(item: &ShapedItem) -> bool {
     // Break after spaces or explicit break items.
     if is_word_separator(item) {

layout/src/text3/knuth_plass.rs

@@ -5,6 +5,8 @@ use std::sync::Arc;
 
 #[cfg(feature = "text_layout_hyphenation")]
 use hyphenation::{Hyphenator, Standard};
+#[cfg(not(feature = "text_layout_hyphenation"))]
+use crate::text3::cache::Standard;
 
 use crate::text3::cache::{
     get_base_direction_from_logical, get_item_measure, is_word_separator, AvailableSpace,

layout/src/thread.rs

@@ -231,6 +231,26 @@ impl Clone for ThreadSendCallback {
     }
 }
 
+impl PartialEq for ThreadSendCallback {
+    fn eq(&self, other: &Self) -> bool {
+        self.cb as usize == other.cb as usize
+    }
+}
+
+impl Eq for ThreadSendCallback {}
+
+impl PartialOrd for ThreadSendCallback {
+    fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Ord for ThreadSendCallback {
+    fn cmp(&self, other: &Self) -> core::cmp::Ordering {
+        (self.cb as usize).cmp(&(other.cb as usize))
+    }
+}
+
 /// Destructor callback for ThreadSender
 pub type ThreadSenderDestructorCallbackType = extern "C" fn(*mut ThreadSenderInner);
 
@@ -255,6 +275,26 @@ impl Clone for ThreadSenderDestructorCallback {
     }
 }
 
+impl PartialEq for ThreadSenderDestructorCallback {
+    fn eq(&self, other: &Self) -> bool {
+        self.cb as usize == other.cb as usize
+    }
+}
+
+impl Eq for ThreadSenderDestructorCallback {}
+
+impl PartialOrd for ThreadSenderDestructorCallback {
+    fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Ord for ThreadSenderDestructorCallback {
+    fn cmp(&self, other: &Self) -> core::cmp::Ordering {
+        (self.cb as usize).cmp(&(other.cb as usize))
+    }
+}
+
 /// Callback that runs when a thread receives a `WriteBack` message
 ///
 /// This callback runs on the main UI thread and has access dir_to: