extract image processing

src/image_processing.rs

@@ -0,0 +1,66 @@
+use crate::cli::ImageProcessingOptions;
+use crate::ledwand_dither::{
+    blur, histogram_correction, median_brightness, ostromoukhov_dither, sharpen,
+};
+use image::imageops::{resize, FilterType};
+use image::{imageops, DynamicImage, ImageBuffer, Luma};
+use servicepoint::{Bitmap, PIXEL_HEIGHT, PIXEL_WIDTH};
+
+pub struct ImageProcessingPipeline {
+    options: ImageProcessingOptions,
+}
+
+impl ImageProcessingPipeline {
+    pub fn new(options: ImageProcessingOptions) -> Self {
+        Self { options }
+    }
+
+    pub fn process(&self, frame: DynamicImage) -> Bitmap {
+        let frame = Self::resize_grayscale(&frame);
+        let frame = self.grayscale_processing(frame);
+        self.grayscale_to_bitmap(frame)
+    }
+
+    fn resize_grayscale(frame: &DynamicImage) -> ImageBuffer<Luma<u8>, Vec<u8>> {
+        let frame = imageops::grayscale(&frame);
+        let frame = resize(
+            &frame,
+            PIXEL_WIDTH as u32,
+            PIXEL_HEIGHT as u32,
+            FilterType::Nearest,
+        );
+        frame
+    }
+
+    fn grayscale_processing(
+        &self,
+        mut frame: ImageBuffer<Luma<u8>, Vec<u8>>,
+    ) -> ImageBuffer<Luma<u8>, Vec<u8>> {
+        if !self.options.no_hist {
+            histogram_correction(&mut frame);
+        }
+
+        let mut orig = frame.clone();
+
+        if !self.options.no_blur {
+            blur(&orig, &mut frame);
+            std::mem::swap(&mut frame, &mut orig);
+        }
+
+        if !self.options.no_sharp {
+            sharpen(&orig, &mut frame);
+            std::mem::swap(&mut frame, &mut orig);
+        }
+        orig
+    }
+
+    fn grayscale_to_bitmap(&self, mut orig: ImageBuffer<Luma<u8>, Vec<u8>>) -> Bitmap {
+        if self.options.no_dither {
+            let cutoff = median_brightness(&orig);
+            let bits = orig.iter().map(move |x| x > &cutoff).collect();
+            Bitmap::from_bitvec(orig.width() as usize, bits)
+        } else {
+            ostromoukhov_dither(orig, u8::MAX / 2)
+        }
+    }
+}