5 files changed, 69 insertions, 5 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 2ac9444..0857ef2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3,6 +3,12 @@
 version = 3
 
 [[package]]
+name = "adler32"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "aae1277d39aeec15cb388266ecc24b11c80469deae6067e17a1a7aa9e5c1f234"
+
+[[package]]
 name = "aho-corasick"
 version = "0.7.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -59,6 +65,25 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
 [[package]]
+name = "crc32fast"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "81156fece84ab6a9f2afdb109ce3ae577e42b1228441eded99bd77f627953b1a"
+dependencies = [
+ "cfg-if 1.0.0",
+]
+
+[[package]]
+name = "deflate"
+version = "0.8.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "73770f8e1fe7d64df17ca66ad28994a0a623ea497fa69486e14984e715c5d174"
+dependencies = [
+ "adler32",
+ "byteorder",
+]
+
+[[package]]
 name = "env_logger"
 version = "0.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -120,11 +145,21 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0ee1c47aaa256ecabcaea351eae4a9b01ef39ed810004e298d2511ed284b1525"
 
 [[package]]
+name = "miniz_oxide"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "791daaae1ed6889560f8c4359194f56648355540573244a5448a83ba1ecc7435"
+dependencies = [
+ "adler32",
+]
+
+[[package]]
 name = "obi"
 version = "0.1.0"
 dependencies = [
  "bitvec",
  "byteorder",
+ "png",
 ]
 
 [[package]]
@@ -134,6 +169,18 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d70072c20945e1ab871c472a285fc772aefd4f5407723c206242f2c6f94595d6"
 
 [[package]]
+name = "png"
+version = "0.16.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3c3287920cb847dee3de33d301c463fba14dda99db24214ddf93f83d3021f4c6"
+dependencies = [
+ "bitflags",
+ "crc32fast",
+ "deflate",
+ "miniz_oxide",
+]
+
+[[package]]
 name = "radium"
 version = "0.6.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
diff --git a/Cargo.toml b/Cargo.toml
index 311e10b..01e7e31 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,8 +8,11 @@ edition = "2018"
 
 [dependencies]
 sdl2 = {version = "0.34", features = ["ttf"]}
-# obi = { git = "https://github.com/nerdypepper/obi", rev = "63af58d6a3fd68bdb313305881627dab534346e2" }
-obi = { path = "../obi"}
+# obi = { git = "https://github.com/nerdypepper/obi", rev = "7773bfb4c63ab3ea49b428e20ef0946b713fd5f5" }
 env_logger = "0.8.3"
 log = "0.4.0"
 pico-args = "0.4.0"
+
+[dependencies.obi]
+path = "../obi"
+features = ["png"]
diff --git a/src/app.rs b/src/app.rs
index d0089e9..66a27e3 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -904,8 +904,7 @@ impl<'ctx> AppState<'ctx> {
                                                 });
                                             }
                                         }
-                                        Brush::Circle(CircleBrush { size })
-                                        | Brush::Line(LineBrush { size, .. }) => {
+                                        Brush::Circle(CircleBrush { size }) => {
                                             let pt = (x, y);
                                             let val = self.active_color;
                                             if let Ok(o) = self.paint_point(pt, val, size) {
diff --git a/src/lisp/error.rs b/src/lisp/error.rs
index f323bb8..9e9dc90 100644
--- a/src/lisp/error.rs
+++ b/src/lisp/error.rs
@@ -98,6 +98,7 @@ pub enum EvalError {
     DivByZero,
     TypeMismatch,
     NoFileName,
+    FileError(io::Error),
     AccessEmptyList,
     InvalidCoordinates((LispNumber, LispNumber)),
     AssertionError { expected: LispExpr, got: LispExpr },
@@ -126,6 +127,7 @@ impl fmt::Display for EvalError {
             Self::TypeMismatch => write!(f, "mismatched types"),
             Self::DivByZero => write!(f, "attempt to divide by zero"),
             Self::NoFileName => write!(f, "no file name specified"),
+            Self::FileError(e) => write!(f, "file error: {}", e),
             Self::AccessEmptyList => write!(f, "attempted to access empty list"),
             Self::InvalidCoordinates((x, y)) => write!(f, "invalid coordinates: {} {}", x, y),
             Self::AssertionError { expected, got } => {
diff --git a/src/lisp/prelude.rs b/src/lisp/prelude.rs
index 7cb46ff..8088510 100644
--- a/src/lisp/prelude.rs
+++ b/src/lisp/prelude.rs
@@ -14,7 +14,7 @@ use crate::{
     utils::{load_script, rect_coords},
 };
 
-use std::convert::TryInto;
+use std::{convert::TryInto, fs::File, io::BufWriter, path::Path};
 
 #[macro_export]
 macro_rules! primitive {
@@ -260,6 +260,18 @@ pub fn new_env() -> Result<Environment, LispError> {
         }
     });
 
+    primitive!(env, Arity::Exact(1), "export-png", |args, app| {
+        if let LispExpr::StringLit(s) = &args[0] {
+            let export_path = Path::new(&s);
+            let file = File::create(export_path).map_err(EvalError::FileError)?;
+            let w = BufWriter::new(file);
+            app.export().write_png(w);
+            Ok(LispExpr::Unit)
+        } else {
+            Err(EvalError::TypeMismatch.into())
+        }
+    });
+
     primitive!(env, Arity::Exact(0), "grid-enabled?", |_, app| {
         Ok(LispExpr::BoolLit(app.grid.enabled))
     });
@@ -524,5 +536,6 @@ pub fn new_env() -> Result<Environment, LispError> {
     primitive!(env, Arity::Exact(1), "id", |args, _| {
         Ok(args[0].clone())
     });
+
     Ok(env)
 }