Make the libraries only used for reftesting opt-in.

Closes #56.

README.md

@@ -57,6 +57,14 @@ To run the demo, make sure NPM and nightly Rust are installed, and run the follo
 
 Then navigate to http://localhost:8000/.
 
+## Testing
+
+Pathfinder contains reference tests that compare its output to that of other rendering libraries,
+such as Cairo. To run them, install Cairo and FreeType if necessary, then perform the above steps,
+substituting the last line with:
+
+    $ cargo run --release --features reftests
+
 ## Authors
 
 The primary author is Patrick Walton (@pcwalton), with contributions from the Servo development

demo/server/Cargo.toml

@@ -3,6 +3,10 @@ name = "pathfinder_server"
 version = "0.1.0"
 authors = ["Patrick Walton <pcwalton@mimiga.net>"]
 
+[features]
+default = []
+reftests = ["rsvg", "cairo-rs", "pathfinder_font_renderer/freetype"]
+
 [dependencies]
 app_units = "0.5"
 base64 = "0.6"
@@ -16,7 +20,6 @@ lru-cache = "0.1"
 rocket = "0.3"
 rocket_codegen = "0.3"
 rocket_contrib = "0.3"
-rsvg = "0.3"
 serde = "1.0"
 serde_derive = "1.0"
 serde_json = "1.0"
@@ -24,13 +27,17 @@ serde_json = "1.0"
 [dependencies.cairo-rs]
 version = "0.3"
 features = ["png"]
+optional = true
+
+[dependencies.rsvg]
+version = "0.3"
+optional = true
 
 [dependencies.fontsan]
 git = "https://github.com/servo/fontsan.git"
 
 [dependencies.pathfinder_font_renderer]
 path = "../../font-renderer"
-features = ["freetype"]
 
 [dependencies.pathfinder_partitioner]
 path = "../../partitioner"

demo/server/src/main.rs

@@ -13,7 +13,6 @@
 
 extern crate app_units;
 extern crate base64;
-extern crate cairo;
 extern crate env_logger;
 extern crate euclid;
 extern crate fontsan;
@@ -24,16 +23,19 @@ extern crate pathfinder_partitioner;
 extern crate pathfinder_path_utils;
 extern crate rocket;
 extern crate rocket_contrib;
-extern crate rsvg;
 
 #[macro_use]
 extern crate lazy_static;
 #[macro_use]
 extern crate serde_derive;
 
+#[cfg(feature = "reftests")]
+extern crate cairo;
+#[cfg(feature = "reftests")]
+extern crate rsvg;
+
 use app_units::Au;
-use cairo::{Format, ImageSurface};
-use euclid::{Point2D, Size2D, Transform2D};
+use euclid::{Point2D, Transform2D};
 use image::{DynamicImage, ImageBuffer, ImageFormat, ImageRgba8};
 use lru_cache::LruCache;
 use pathfinder_font_renderer::{FontContext, FontInstance, FontKey, GlyphImage};
@@ -49,7 +51,6 @@ use rocket::http::{ContentType, Header, Status};
 use rocket::request::Request;
 use rocket::response::{NamedFile, Redirect, Responder, Response};
 use rocket_contrib::json::Json;
-use rsvg::{Handle, HandleExt};
 use std::fs::File;
 use std::io::{self, Cursor, Read};
 use std::ops::Range;
@@ -61,6 +62,13 @@ use std::u32;
 #[cfg(target_os = "macos")]
 use pathfinder_font_renderer::core_graphics;
 
+#[cfg(feature = "reftests")]
+use euclid::Size2D;
+#[cfg(feature = "reftests")]
+use cairo::{Format, ImageSurface};
+#[cfg(feature = "reftests")]
+use rsvg::{Handle, HandleExt};
+
 const SUGGESTED_JSON_SIZE_LIMIT: u64 = 32 * 1024 * 1024;
 
 const CUBIC_ERROR_TOLERANCE: f32 = 0.1;
@@ -192,6 +200,7 @@ enum FontError {
 
 #[derive(Clone, Copy, Debug, Serialize, Deserialize)]
 enum SvgError {
+    ReftestsDisabled,
     UnknownBuiltinSvg,
     LoadingFailed,
     ImageWritingFailed,
@@ -353,6 +362,7 @@ fn otf_data_from_request(face: &FontRequestFace) -> Result<Arc<Vec<u8>>, FontErr
 }
 
 // Fetches the SVG data.
+#[cfg(feature = "reftests")]
 fn svg_data_from_request(builtin_svg_name: &str) -> Result<Arc<Vec<u8>>, SvgError> {
     // Read in the builtin SVG.
     match BUILTIN_SVGS.iter().filter(|& &(name, _)| name == builtin_svg_name).next() {
@@ -619,6 +629,7 @@ fn render_reference_text(request: Json<RenderTextReferenceRequest>)
     Ok(reference_image)
 }
 
+#[cfg(feature = "reftests")]
 #[post("/render-reference/svg", format = "application/json", data = "<request>")]
 fn render_reference_svg(request: Json<RenderSvgReferenceRequest>)
                         -> Result<ReferenceImage, SvgError> {
@@ -656,6 +667,14 @@ fn render_reference_svg(request: Json<RenderSvgReferenceRequest>)
     })
 }
 
+#[cfg(not(feature = "reftests"))]
+#[post("/render-reference/svg", format = "application/json", data = "<request>")]
+#[allow(unused_variables)]
+fn render_reference_svg(request: Json<RenderSvgReferenceRequest>)
+                        -> Result<ReferenceImage, SvgError> {
+    Err(SvgError::ReftestsDisabled)
+}
+
 // Static files
 #[get("/")]
 fn static_index() -> io::Result<NamedFile> {