add SANE_{,UN}FIX

sane-sys/src/lib.rs

@@ -16,6 +16,14 @@ pub const fn SANE_VERSION_BUILD(code: SANE_Int) -> SANE_Word {
     (code >> 0) as SANE_Word & 0xffff
 }
 
+pub fn SANE_FIX(v: f64) -> SANE_Word {
+    (v * (1 << SANE_FIXED_SCALE_SHIFT) as f64) as SANE_Word
+}
+
+pub fn SANE_UNFIX(v: SANE_Word) -> f64 {
+    v as f64 / (1 << SANE_FIXED_SCALE_SHIFT) as f64
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;