From a6dfec305a53c6a7618b98f43a6b4b89cfb76102 Mon Sep 17 00:00:00 2001
From: Minijackson <minijackson@riseup.net>
Date: Sun, 7 Oct 2018 23:40:35 +0200
Subject: Add support for PulseEffects

---
 src/pa_effects.rs | 125 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 125 insertions(+)
 create mode 100644 src/pa_effects.rs

(limited to 'src/pa_effects.rs')

diff --git a/src/pa_effects.rs b/src/pa_effects.rs
new file mode 100644
index 0000000..9ed0a1f
--- /dev/null
+++ b/src/pa_effects.rs
@@ -0,0 +1,125 @@
+use cli::pa_effects::*;
+use utils::*;
+use Filter;
+
+use failure::Error;
+
+use serde_json;
+
+const DEFAULT_PRESET: &'static str = include_str!("../res/default-pa-effects-preset.json");
+
+pub fn main(cmd: Command) -> Result<(), Error> {
+    use cli::pa_effects::Command::*;
+
+    match cmd {
+        ExportPreset(args) => export_preset(args),
+    }
+}
+
+fn export_preset(args: ExportPresetCli) -> Result<(), Error> {
+    debug!("Parsing base preset");
+    let mut preset: serde_json::Value = match args.base_preset {
+        Some(file) => serde_json::from_str(&read_filearg_to_str(&file)?),
+        None => serde_json::from_str(&DEFAULT_PRESET),
+    }?;
+
+    let filter = read_filter_from_arg(&args.file)?;
+
+    preset["output"]["equalizer"] = filter_to_eq_preset(filter);
+
+    println!("{}", preset);
+    Ok(())
+}
+
+fn filter_to_eq_preset(mut filter: Filter) -> serde_json::Value {
+    if filter.frequencies.len() > 30 {
+        info!("More than 30 frequencies specified, taking the approximative approach");
+        filter = simplify_filter(filter);
+    }
+
+    let mut equalizer: serde_json::Value = json!({
+        "state": "true",
+        "num-bands": filter.frequencies.len(),
+        "input-gain": 0,
+        "output-gain": 0,
+    });
+
+    for (i, (frequency, coeff)) in filter
+        .frequencies
+        .into_iter()
+        .zip(filter.coefficients)
+        .enumerate()
+    {
+        equalizer[format!("band{}", i)] = json!({
+            "gain": coeff,
+            "frequency": frequency,
+            "type": "peak",
+        });
+    }
+
+    equalizer
+}
+
+fn simplify_filter(filter: Filter) -> Filter {
+    //let partition_size = (filter.frequencies.len() as f64 / 30f64).floor() as usize;
+    let mut partition_size = filter.frequencies.len() / 30;
+    let step_error = filter.frequencies.len() as f64 % 30f64;
+    if step_error != 0f64 {
+        info!("The approximation will be imperfect");
+        partition_size += 1;
+    }
+
+    //let mut cumulative_error = 0f64;
+
+    let frequencies = filter.frequencies.chunks(partition_size).map(|vec| {
+        let sum: u32 = vec.iter().sum();
+        sum / vec.len() as u32
+    }).collect();
+
+    let coefficients = filter.coefficients.chunks(partition_size).map(|vec| {
+        let sum: f64 = vec.iter().sum();
+        sum / vec.len() as f64
+    }).collect();
+
+    Filter {
+        preamp: filter.preamp,
+        frequencies, coefficients
+    }
+}
+
+/*
+trait MultiPartitionnable {
+    type Item;
+
+    fn multi_partition(self, size: usize, wanted_parts: usize) -> MultiPartition<Self>
+    where
+        Self: Iterator + Sized,
+    {
+        MultiPartition {
+            iter: self,
+            size,
+            wanted_parts,
+            cumulative_error: 0f64,
+        }
+    }
+}
+
+impl<I> MultiPartitionnable for Iterator<Item = I> {
+    type Item = I;
+}
+
+struct MultiPartition<I: Iterator> {
+    iter: I,
+    size: usize,
+    wanted_parts: usize,
+    cumulative_error: f64,
+}
+
+impl<I: Iterator> Iterator for MultiPartition<I> {
+    type Item = Vec<I::Item>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+
+    }
+}
+*/
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