Stabilize PRD site rendering refresh

crates/ely_app/src/shell/web_surface_image.rs

@@ -0,0 +1,28 @@
+use image::{ImageBuffer, Rgba, imageops::FilterType};
+
+const WEB_SURFACE_IMAGE_MAX_EDGE: u32 = 1024;
+
+pub(super) fn renderable_image_buffer(
+    buffer: ImageBuffer<Rgba<u8>, Vec<u8>>,
+) -> ImageBuffer<Rgba<u8>, Vec<u8>> {
+    let largest_edge = buffer.width().max(buffer.height());
+    if largest_edge <= WEB_SURFACE_IMAGE_MAX_EDGE {
+        return buffer;
+    }
+
+    image::imageops::resize(
+        &buffer,
+        scaled_image_dimension(buffer.width(), largest_edge),
+        scaled_image_dimension(buffer.height(), largest_edge),
+        FilterType::Triangle,
+    )
+}
+
+fn scaled_image_dimension(dimension: u32, largest_edge: u32) -> u32 {
+    let numerator = u64::from(dimension) * u64::from(WEB_SURFACE_IMAGE_MAX_EDGE);
+    let rounded = (numerator + u64::from(largest_edge / 2)) / u64::from(largest_edge);
+    match u32::try_from(rounded.max(1)) {
+        Ok(value) => value,
+        Err(_) => WEB_SURFACE_IMAGE_MAX_EDGE,
+    }
+}