feat: allow specifying strand subset

src/lib.rs

@@ -33,6 +33,9 @@ pub struct Layout {
 
     pub num_panels_h: u32,
     pub num_panels_v: u32,
+
+    pub total_strands: u32,
+    pub first_strand_index: u32,
 }
 
 impl Layout {

src/main.rs

@@ -154,6 +154,9 @@ fn main() -> anyhow::Result<()> {
 
         num_panels_h: 6,
         num_panels_v: 1,
+
+        total_strands: 24,
+        first_strand_index: 8,
     };
 
     match args.action {

src/sender.rs

@@ -64,9 +64,21 @@ pub fn send_frame(
     frame_num: u32,
     image: &RgbImage,
 ) -> Result<(), SenderError> {
-    for strand_num in 0..layout.num_strands() {
-        let data = Strandifier::make_strand(layout, image, strand_num)?;
-        send_strand(socket, strand_num, frame_num, data)?;
+    for strand_num in 0..layout.total_strands {
+        if strand_num >= layout.first_strand_index
+            && strand_num < layout.num_strands() + layout.first_strand_index
+        {
+            let data =
+                Strandifier::make_strand(layout, image, strand_num - layout.first_strand_index)?;
+            send_strand(socket, strand_num as u32, frame_num, data)?;
+        } else {
+            send_strand(
+                socket,
+                strand_num as u32,
+                frame_num,
+                vec![Rgb([0, 0, 0]); layout.strand_len() as usize],
+            )?;
+        }
     }
 
     let mut buf = vec![0; 100];