From 5a4e7a838d7364b9b776d3200075335070c2a287 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sat, 2 Jan 2021 01:13:32 +0000
Subject: [PATCH] wip coords matrix

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 Cargo.lock.example |  1 +
 wdriver.rs         | 26 ++++++++++++++++++++++++--
 wdriver/Cargo.toml |  1 +
 3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/Cargo.lock.example b/Cargo.lock.example
index 94591817..bfac8552 100644
--- a/Cargo.lock.example
+++ b/Cargo.lock.example
@@ -1675,6 +1675,7 @@ dependencies = [
  "fehler",
  "humantime",
  "if_chain",
+ "itertools",
  "libc",
  "log 0.4.11",
  "ndarray",
diff --git a/wdriver.rs b/wdriver.rs
index 8705a9bc..1fbdb0e6 100644
--- a/wdriver.rs
+++ b/wdriver.rs
@@ -782,14 +782,36 @@ impl<'g> PieceElement<'g> {
 
   #[throws(AE)]
   pub fn posw(&self) -> WebPos {
-    let ary = self.w.matrix.get_or_try_init(||{
+    let mat = self.w.matrix.get_or_try_init(||{
       let ary = self.w.su.driver.execute_script(r#"
         let m = space.getScreenCTM();
         return [m.a, m.b, m.c, m.d, m.e, m.f];
       "#)?;
-      dbg!(ary.value());
+      let ary = ary.value();
+      dbg!(ary);
+
+      let mat = (||{
+        let ary = ary.as_array().ok_or_else(|| anyhow!("not array"))?;
+        let mut mat = ndarray::Array2::<f64>::zeros((3,3));
+        for got in itertools::Itertools::zip_longest(
+          [11, 12, 21, 22, 41, 42].iter(),
+          // ^ from https://developer.mozilla.org/en-US/docs/Web/API/DOMMatrix
+          ary.iter(),
+        ) {
+          let (mij, v) = got.both().ok_or_else(|| anyhow!("wrong length"))?;
+          let adj = |v| (if v == 4 { 3 } else { v }) - 1;
+          let i = adj(mij / 10);
+          let j = adj(mij % 10);
+          mat[(i,j)] = v.as_f64().ok_or_else(|| anyhow!("entry not f64"))?;
+        }
+        Ok::<_,AE>(mat)
+      })()
+        .with_context(|| format!("getScreenCGM script gave {:?}", &ary))?;
+
+      dbg!(mat);
       Ok::<_,AE>(())
     })?;
+    let () = mat;
     (||{
       Ok::<_,AE>( todo!() )
     })()
diff --git a/wdriver/Cargo.toml b/wdriver/Cargo.toml
index e6f87433..239f22f9 100644
--- a/wdriver/Cargo.toml
+++ b/wdriver/Cargo.toml
@@ -19,6 +19,7 @@ env_logger = "0.8"
 fehler = "1"
 humantime = "2"
 if_chain = "1"
+itertools = "0.9"
 log = "0.4"
 libc = "0.2"
 nix = "0.19"
-- 
2.30.2