1 files changed, 83 insertions, 0 deletions
diff --git a/histogrammer/src/main.rs b/histogrammer/src/main.rs
new file mode 100644
index 0000000..9025787
--- /dev/null
+++ b/histogrammer/src/main.rs
@@ -0,0 +1,83 @@
+use image;
+
+use plotters::prelude::*;
+
+fn main() {
+    let im = image::open("/misc/camera_recorder/ngc6888_o3_20201002_set2_1.png").expect("can load image");
+    let im = match im {
+        image::DynamicImage::ImageLuma16(ref p) => Some(p),
+        _ => None,
+    };
+    if let Some(img) = im {
+        let (w, h) = img.dimensions();
+        println!("got 16-bit greyscale image: {}x{}", w, h);
+        let total = w * h;
+//        let mut histogram = [0u32; 65536];
+//        for px in img.enumerate_pixels() {
+//            histogram[px.2[0] as usize] += 1;
+//        }
+
+        let hi = img.enumerate_pixels().map(|x| ((x.2[0]) as f64, if x.2[0] == 0 { 0f64 } else { 1f64 / (total as f64) }));
+
+ //       println!("hist: {:?}", &histogram[..]);
+
+        fn draw_hist<I: IntoIterator<Item=(f64, f64)>>(hist_data: I, start: usize, end: usize) -> Vec<u8> {
+            assert!(start <= end);
+
+            let mut data = vec![0; 640 * 480 * 3];
+
+            {
+                let mut root = BitMapBackend::with_buffer(&mut data, (640, 480)).into_drawing_area();
+                root.fill(&WHITE);
+
+                let mut chart = ChartBuilder::on(&root)
+                    .margin(5)
+                    .caption("Pixel histogram", ("sans-serif", 30))
+                    .set_label_area_size(LabelAreaPosition::Left, 60)
+                    .set_label_area_size(LabelAreaPosition::Bottom, 60)
+                    .set_label_area_size(LabelAreaPosition::Right, 60)
+                    .build_cartesian_2d((start as f64)..(end as f64), 0f64..2.0).unwrap()
+                    .set_secondary_coord(
+                        ((start as f64)..(end as f64)).step(1.0).use_round().into_segmented(),
+                        0f64..0.05f64,
+                    );
+
+                chart
+                    .configure_mesh()
+                    .disable_x_mesh()
+                    .disable_y_mesh()
+                    .y_desc("Percentage")
+                    .draw().unwrap();
+
+                chart.configure_secondary_axes().y_desc("Count").draw().unwrap();
+
+                let actual = Histogram::vertical(chart.borrow_secondary())
+                    .style(GREEN.filled())
+                    .margin(3)
+                    .data(hist_data);
+
+                chart
+                    .draw_secondary_series(actual).unwrap()
+                    .label("Observed")
+                    .legend(|(x, y)| Rectangle::new([(x, y - 5), (x + 10, y + 5)], GREEN.filled()));
+
+                chart.configure_series_labels().draw().unwrap();
+            }
+
+            data
+        }
+
+//        let data = draw_hist(&histogram[..], 0, 6000);
+        let data = draw_hist(hi, 0, 6000);
+
+        use show_image::make_window;
+        let window = make_window("image").expect("can make the window");
+        let image_info = show_image::ImageInfo::rgb8(640, 480);
+        window.set_image(&(data, image_info), "histogram");
+        loop {
+        std::thread::sleep(std::time::Duration::from_millis(10000));
+        }
+    } else {
+        panic!("image was not 16-bit greyscale");
+    }
+}