initial commit w/ working waveform from default stereo audio output monitor capture via pw

src/utils.rs

@@ -0,0 +1,38 @@
+pub fn update_waveform( rgba: &mut crate::Rgba, samples: (&Vec<f32>, &Vec<f32>) ) {
+    let (left_samples, right_samples) = samples;
+
+    rgba.pixels.fill(255);
+
+    let left_column_width : usize =  left_samples.len() / rgba.width as usize;
+    let right_column_width : usize = right_samples.len() / rgba.width as usize;
+    let mut last_rows = ((rgba.height/2) as usize, (rgba.height/2) as usize);
+    for x in 0..rgba.width as usize {
+        // LEFT CHANNEL
+        let column_values : &[f32] = &left_samples[x*left_column_width..(x+1)*left_column_width];
+        let column_average : f32 = (column_values.iter().cloned().reduce(|acc, v| acc+v).unwrap_or(0f32) / column_values.len() as f32).clamp(-0.99, 0.99);
+        let row = (128f32 - (column_average * 128f32)).round() as usize;
+        
+        // Draw vertical lines from last row
+        let range : Vec<usize> = if row <= last_rows.0 {(row..=last_rows.0).collect()} else {(last_rows.0..=row).rev().collect()};
+        for row in range {
+            let coord = (row * rgba.width as usize * 4) + (x * 4);
+            rgba.pixels[coord+0] = 0;
+            rgba.pixels[coord+1] = 0;
+        }
+        last_rows.0 = row;
+
+        // RIGHT CHANNEL
+        let column_values : &[f32] = &right_samples[x*right_column_width..(x+1)*right_column_width];
+        let column_average : f32 = (column_values.iter().cloned().reduce(|acc, v| acc+v).unwrap_or(0f32) / column_values.len() as f32).clamp(-0.99, 0.99);
+        let row = (128f32 - (column_average * 128f32)).round() as usize;
+        
+        // Draw vertical lines from last row
+        let range : Vec<usize> = if row <= last_rows.1 {(row..=last_rows.1).collect()} else {(last_rows.1..=row).rev().collect()};
+        for row in range {
+            let coord = (row * rgba.width as usize * 4) + (x * 4);
+            rgba.pixels[coord+1] = 0;
+            rgba.pixels[coord+2] = 0;
+        }
+        last_rows.1 = row;
+    }
+}