basic luma8 source

src/luma_luma_source.rs

@@ -0,0 +1,63 @@
+use crate::LuminanceSource;
+
+pub struct Luma8LuminanceSource(u32, u32, Vec<u8>, bool);
+impl LuminanceSource for Luma8LuminanceSource {
+    fn getRow(&self, y: usize) -> Vec<u8> {
+        self.2
+            .chunks_exact(y * self.0 as usize)
+            .skip(y)
+            .take(1)
+            .flatten()
+            .map(|byte| Self::invert_if_should(*byte, self.3))
+            .collect()
+    }
+
+    fn getMatrix(&self) -> Vec<u8> {
+        self.2
+            .iter()
+            .map(|byte| Self::invert_if_should(*byte, self.3))
+            .collect()
+    }
+
+    fn getWidth(&self) -> usize {
+        self.0 as usize
+    }
+
+    fn getHeight(&self) -> usize {
+        self.1 as usize
+    }
+
+    fn invert(&mut self) {
+        self.3 = !self.3;
+    }
+
+    fn isCropSupported(&self) -> bool {
+        false
+    }
+
+    fn crop(
+        &self,
+        _left: usize,
+        _top: usize,
+        _width: usize,
+        _height: usize,
+    ) -> Result<Box<dyn LuminanceSource>, crate::Exceptions> {
+        Err(crate::Exceptions::UnsupportedOperationException(Some(
+            "This luminance source does not support cropping.".to_owned(),
+        )))
+    }
+}
+impl Luma8LuminanceSource {
+    pub fn new(source: Vec<u8>, width: u32, height: u32) -> Self {
+        Self(width, height, source, false)
+    }
+
+    #[inline(always)]
+    fn invert_if_should(byte: u8, invert: bool) -> u8 {
+        if invert {
+            255 - byte
+        } else {
+            byte
+        }
+    }
+}