Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

1 files changed, 74 insertions, 0 deletions

diff --git a/vendor/exr/examples/6_extract_mip_map_pngs.rs b/vendor/exr/examples/6_extract_mip_map_pngs.rs
new file mode 100644
index 0000000..152c7c1
--- /dev/null
+++ b/vendor/exr/examples/6_extract_mip_map_pngs.rs
@@ -0,0 +1,74 @@
+
+extern crate image as png;
+use std::cmp::Ordering;
+
+extern crate exr;
+
+/// Extract all exr pixel information into pngs.
+/// Writes each channel of each mip map of each layer as one grayscale png.
+/// May appear black for single-color images.
+pub fn main() {
+    use exr::prelude::*;
+
+    let path = "mip_maps.exr";
+    let start_time = ::std::time::Instant::now();
+
+    // load the exr file from disk with multi-core decompression
+    let image = read_all_data_from_file(path)
+        .expect("run example `5c_write_mip_maps` to generate this image file");
+
+    // warning: highly unscientific benchmarks ahead!
+    println!("\nloaded file in {:?}s", start_time.elapsed().as_secs_f32());
+    let _ = std::fs::create_dir_all("pngs/");
+    println!("writing images...");
+
+    for (layer_index, layer) in image.layer_data.iter().enumerate() {
+        let layer_name = layer.attributes.layer_name.as_ref()
+            .map_or(String::from("1"), Text::to_string);
+
+        for channel in &layer.channel_data.list {
+            for (level, level_size) in layer.levels_with_resolution(&channel.sample_data) {
+                let data : Vec<f32> = level.values_as_f32().collect();
+
+                save_f32_image_as_png(&data, level_size, format!(
+                    "pngs/{} ({}) {}.{}x{}.png",
+                    layer_index, layer_name, channel.name,
+                    level_size.width(), level_size.height(),
+                ))
+            }
+        }
+    }
+
+    /// Save raw float data to a PNG file, doing automatic brightness adjustments per channel
+    fn save_f32_image_as_png(data: &[f32], size: Vec2<usize>, name: String) {
+        let mut png_buffer = png::GrayImage::new(size.width() as u32, size.height() as u32);
+        let mut sorted = Vec::from(data);
+        sorted.sort_by(|a, b| a.partial_cmp(b).unwrap_or(Ordering::Less));
+
+        // percentile normalization
+        let max = sorted[7 * sorted.len() / 8];
+        let min = sorted[1 * sorted.len() / 8];
+
+        // primitive tone mapping
+        let tone = |v: f32| (v - 0.5).tanh() * 0.5 + 0.5;
+        let max_toned = tone(*sorted.last().unwrap());
+        let min_toned = tone(*sorted.first().unwrap());
+
+        // for each pixel, tone map the value
+        for (x, y, pixel) in png_buffer.enumerate_pixels_mut() {
+            let v = data[y as usize * size.0 + x as usize];
+            let v = (v - min) / (max - min);
+            let v = tone(v);
+
+            let v = (v - min_toned) / (max_toned - min_toned);
+
+            // TODO does the `image` crate expect gamma corrected data?
+            *pixel = png::Luma([(v.max(0.0).min(1.0) * 255.0) as u8]);
+        }
+
+        png_buffer.save(&name).unwrap();
+    }
+
+    println!("extracted all layers to folder `./pngs/*.png`");
+}
+