Fix gridbool iter when gridbool is big (W*H > 65535)

We multiply W and H to iterate, but their product may not fill in
their own u16 type - so we have to convert them to usize beforehand.

src/sqrid/gridbool.rs

@@ -151,7 +151,7 @@ impl<const W: u16, const H: u16, const WORDS: usize> Gridbool<W, H, WORDS> {
     /// Iterate over all `true`/`false` values in the `Gridbool`.
     #[inline]
     pub fn iter(&self) -> impl iter::Iterator<Item = bool> + '_ {
-        (0..(W * H)).map(move |i| {
+        (0..(W as usize * H as usize)).map(move |i| {
             let (byte, bit) = Self::byte_bit(i);
             self.0[byte] & bit != 0
         })

tests/gridbool_tests.rs

@@ -15,8 +15,11 @@ type Gbool2 = sqrid::Gridbool<11, 3, 2>;
 type Qa5 = sqrid::Qa<5, 5>;
 type Gbool5 = sqrid::Gridbool<5, 5, 1>;
 
-type _QaScale = sqrid::Qa<0xffff, 0xffff>;
-type _GridboolScale = sqrid::gridbool_create!(_QaScale);
+type QaScale = sqrid::Qa<2000, 2000>;
+type GridboolScale = sqrid::gridbool_create!(QaScale);
+
+type _QaMax = sqrid::Qa<0xffff, 0xffff>;
+type _GridboolMax = sqrid::gridbool_create!(_QaMax);
 
 #[test]
 fn test_getset() -> Result<()> {
@@ -148,3 +151,18 @@ fn test_rotate() -> Result<()> {
     assert_eq!(gb2, gb);
     Ok(())
 }
+
+#[test]
+fn test_scale() -> Result<()> {
+    let mut gb = Box::new(GridboolScale::default());
+    for qa in QaScale::iter() {
+        gb.set_t(qa);
+    }
+    for value in gb.iter() {
+        // Dummy operation, we are really just testing gb.iter
+        if !value {
+            break;
+        }
+    }
+    Ok(())
+}