adler feature, etc.

1 files changed, 22 insertions, 5 deletions

diff --git a/README.md b/README.md
index 04e126a..c50e4da 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 Tiny Rust PNG decoder.
 
-This decoder can be used without `std` or even `alloc` by disabling the `std` feature (enabled by default).
+This decoder can be used without `std` or `alloc` by disabling the `std` feature (enabled by default).
 
 ## Goals
 
@@ -15,17 +15,19 @@ This decoder can be used without `std` or even `alloc` by disabling the `std` fe
 
 - Adam7 interlacing (interlaced PNGs are rare, and this would require additional code complexity
   — but if you want to add it behind a feature gate, feel free to)
-- Sacrificing code size for speed (except maybe with a feature enabled)
+- Sacrificing code size a lot for speed (except maybe with a feature enabled)
+- Checking block CRCs (increased code complexity probably isn't worth it,
+  and there's already Adler32 checksums for IDAT chunks)
 
 ## Example usage
 
-Very basic usage:
+Basic usage:
 
 ```rust
 let mut buffer = vec![0; 1 << 20]; // hope this is big enough!
 let mut png = &include_bytes!("image.png")[..];
 let image = tiny_png::read_png(&mut png, None, &mut buffer).expect("bad PNG");
-println!("{}x{} image", image.width(), image.height());
+println!("{}×{} image", image.width(), image.height());
 let pixels = image.pixels();
 println!("top-left pixel is #{:02x}{:02x}{:02x}", pixels[0], pixels[1], pixels[2]);
 // (^ this only makes sense for RGB 8bpc images)
@@ -39,8 +41,23 @@ let header = tiny_png::read_png_header(&mut png).expect("bad PNG");
 println!("need {} bytes of memory", header.required_bytes());
 let mut buffer = vec![0; header.required_bytes()];
 let image = tiny_png::read_png(&mut png, Some(&header), &mut buffer).expect("bad PNG");
-println!("{}x{} image", image.width(), image.height());
+println!("{}×{} image", image.width(), image.height());
 let pixels = image.pixels();
 println!("top-left pixel is #{:02x}{:02x}{:02x}", pixels[0], pixels[1], pixels[2]);
 // (^ this only makes sense for RGB 8bpc images)
 ```
+
+## Features
+
+- `std` (default: enabled) — use standard library. enabling it allows you to read from `BufReader<File>` but
+   adds `std` as a dependency.
+- `adler` (default: disabled) — check Adler-32 checksums. slightly increases code size and
+  slightly decreases performance but verifies integrity of PNG files.
+
+## Development
+
+A `pre-commit` git hook is provided to run `cargo fmt` and `cargo clippy`. You can install it with:
+
+```sh
+ln -s ../../pre-commit .git/hooks/
+```