1 files changed, 46 insertions, 0 deletions
diff --git a/vendor/exr/examples/7_crop_alpha_any_image.rs b/vendor/exr/examples/7_crop_alpha_any_image.rs
new file mode 100644
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--- /dev/null
+++ b/vendor/exr/examples/7_crop_alpha_any_image.rs
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+
+extern crate image as png;
+
+extern crate exr;
+
+/// Read an arbitrary image, crop away transparent pixels,
+/// then write the cropped result to another file.
+pub fn main() {
+    use exr::prelude::*;
+
+    let path = "tests/images/valid/custom/oh crop.exr";
+
+    // loads any image (excluding deep data)
+    let image: FlatImage = read_all_flat_layers_from_file(path)
+        .expect("this file exists in the exrs repository. download that?");
+
+    // construct a cropped image
+    let image = Image {
+        attributes: image.attributes,
+
+        // crop each layer
+        layer_data: image.layer_data.into_iter().map(|layer|{
+            println!("cropping layer {:#?}", layer);
+
+            // find the alpha channel of the layer
+            let alpha_channel_index = layer.channel_data.list.iter()
+                .position(|channel| channel.name.eq_case_insensitive("A"));
+
+            // if has alpha, crop it where alpha is zero
+            if let Some(alpha_channel_index) = alpha_channel_index {
+                layer.crop_where(|pixel: FlatSamplesPixel| pixel[alpha_channel_index].is_zero())
+                    .or_crop_to_1x1_if_empty() // do not remove empty layers from image, because it could result in an image without content
+                    .reallocate_cropped() // actually perform the crop operation
+            }
+            else {
+                // return the original layer, as no alpha channel can be used for cropping
+                layer
+            }
+
+        }).collect::<Layers<_>>(),
+    };
+
+    image.write().to_file("cropped.exr").unwrap();
+    println!("cropped file to cropped.exr");
+}
+