From 7773bfb4c63ab3ea49b428e20ef0946b713fd5f5 Mon Sep 17 00:00:00 2001
From: Akshay <nerdy@peppe.rs>
Date: Fri, 23 Apr 2021 17:16:33 +0530
Subject: add basic obi to png conversions

---
 .gitignore     |  1 +
 src/convert.rs | 26 ++++++++++++++++++++++++++
 src/lib.rs     |  5 +++++
 3 files changed, 32 insertions(+)
 create mode 100644 src/convert.rs

diff --git a/.gitignore b/.gitignore
index 96ef6c0..95dfa36 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 /target
 Cargo.lock
+*.png
diff --git a/src/convert.rs b/src/convert.rs
new file mode 100644
index 0000000..368b2ef
--- /dev/null
+++ b/src/convert.rs
@@ -0,0 +1,26 @@
+use crate::{
+    error::{OBIError, OBIResult},
+    CompressionType, Image,
+};
+
+use std::io::Write;
+
+use png::{BitDepth, ColorType, Encoder, Writer};
+
+pub fn to_png<W: Write>(writer: W, img: &Image) -> Writer<W> {
+    let mut encoder = Encoder::new(writer, img.width(), img.height());
+    encoder.set_color(ColorType::RGBA);
+    encoder.set_depth(BitDepth::Eight);
+    let mut writer = encoder.write_header().unwrap();
+    writer
+        .write_image_data(
+            &img.data
+                .iter()
+                .take((img.width() * img.height()) as usize)
+                .map(|x| if *x { vec![255; 4] } else { vec![0, 0, 0, 255] })
+                .flatten()
+                .collect::<Vec<_>>()[..],
+        )
+        .unwrap();
+    writer
+}
diff --git a/src/lib.rs b/src/lib.rs
index 05070cb..b6cab75 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -4,6 +4,7 @@
 
 use std::io;
 
+pub mod convert;
 mod decode;
 mod encode;
 pub mod error;
@@ -165,4 +166,8 @@ impl Image {
     pub fn decode(data: &mut io::Cursor<Vec<u8>>) -> OBIResult<Image> {
         decode::decode_image(data)
     }
+
+    pub fn write_png<W: io::Write>(&self, writer: W) -> png::Writer<W> {
+        convert::to_png(writer, self)
+    }
 }
-- 
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