Make external dependencies optional

Cargo.toml

@@ -12,12 +12,18 @@ homepage = "https://github.com/image-rs/imageproc"
 exclude = [".github/*", "examples/*", "tests/*"]
 
 [features]
-default = ["rayon", "image/default"]
+default = ["rayon", "image/default", "text", "image_hash"]
 display-window = ["sdl2"]
 rayon = ["dep:rayon", "image/rayon"]
 
+# Option: enable image_hash
+image_hash = ["dep:rustdct"]
+
+# Option: enable drawing::text
+text = ["dep:ab_glyph"]
+
 [dependencies]
-ab_glyph = { version = "0.2.23", default-features = false, features = ["std"] }
+ab_glyph = { version = "0.2.23", default-features = false, features = ["std"], optional = true}
 approx = { version = "0.5", default-features = false }
 image = { version = "0.25.0", default-features = false }
 itertools = { version = "0.14.0", default-features = false, features = [
@@ -36,7 +42,7 @@ sdl2 = { version = "0.38.0", optional = true, default-features = false, features
     "bundled",
 ] }
 katexit = { version = "0.1.4", optional = true, default-features = false }
-rustdct = "0.7.1"
+rustdct = { version = "0.7.1", optional = true }
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 getrandom = { version = "0.3.0", default-features = false, features = ["wasm_js"] }

src/drawing/mod.rs

@@ -32,7 +32,10 @@ pub use self::rect::{
     draw_filled_rect, draw_filled_rect_mut, draw_hollow_rect, draw_hollow_rect_mut,
 };
 
+#[cfg(feature = "text")]
 mod text;
+
+#[cfg(feature = "text")]
 pub use self::text::{draw_text, draw_text_mut, text_size};
 
 mod fill;

src/lib.rs

@@ -37,6 +37,7 @@ pub mod gradients;
 pub mod haar;
 pub mod hog;
 pub mod hough;
+#[cfg(feature = "image_hash")]
 pub mod image_hash;
 pub mod integral_image;
 pub mod kernel;

tests/regression.rs

@@ -952,6 +952,7 @@ fn test_bilateral_filter() {
 }
 
 #[test]
+#[cfg(feature = "text")]
 fn test_draw_text() {
     let font_bytes = include_bytes!("data/fonts/DejaVuSans.ttf");
     let font = ab_glyph::FontRef::try_from_slice(font_bytes).unwrap();