rust: add poc-kittyzapper example

- fix ncdirect_[b|f]g_rgb8 functions.
- fix NcDirect.bg_rgb8 method.
- new printf![] macro.

rust/examples/poc-kittyzapper.rs

@@ -0,0 +1,22 @@
+//! based on the proof of concept at ../../src/poc/kittyzapper.c
+
+use libnotcurses_sys::*;
+
+fn main() {
+    let ncd = NcDirect::new();
+    ncd.fg_rgb8(100, 100, 100);
+    ncd.bg_rgb8(0xff, 0xff, 0xff);
+    printf!("a");
+    ncd.bg_rgb8(0, 0, 0);
+    printf!("b");
+    printf!(" ");
+    printf!(" ");
+    ncd.bg_rgb8(0, 0, 1);
+    printf!("c");
+    printf!(" ");
+    printf!(" ");
+    ncd.bg_rgb8(0xff, 0xff, 0xff);
+    printf!("d");
+    printf!("\n");
+    ncd.stop();
+}

rust/src/direct/methods.rs

@@ -137,7 +137,7 @@ impl NcDirect {
     ///
     /// *C style function: [ncdirect_bg_rgb()][crate::ncdirect_bg_rgb].*
     pub fn bg_rgb8(&mut self, red: NcColor, green: NcColor, blue: NcColor) -> NcResult {
-        crate::ncdirect_fg_rgb8(self, red, green, blue)
+        crate::ncdirect_bg_rgb8(self, red, green, blue)
     }
 
     /// Removes the specified styles.

rust/src/direct/reimplemented.rs

@@ -43,12 +43,8 @@ pub fn ncdirect_fg_rgb8(
     green: NcColor,
     blue: NcColor,
 ) -> NcResult {
-    unsafe {
-        crate::ncdirect_fg_rgb(
-            ncd,
-            (red as NcRgb) << 16 + (green as NcRgb) << 8 + blue as NcRgb,
-        )
-    }
+    let rgb = (red as NcRgb) << 16 | (green as NcRgb) << 8 | blue as NcRgb;
+    unsafe { crate::ncdirect_fg_rgb(ncd, rgb) }
 }
 
 /// Sets the background [NcColor] components.
@@ -61,10 +57,6 @@ pub fn ncdirect_bg_rgb8(
     green: NcColor,
     blue: NcColor,
 ) -> NcResult {
-    unsafe {
-        crate::ncdirect_bg_rgb(
-            ncd,
-            (red as NcRgb) << 16 + (green as NcRgb) << 8 + blue as NcRgb,
-        )
-    }
+    let rgb = (red as NcRgb) << 16 | (green as NcRgb) << 8 | blue as NcRgb;
+    unsafe { crate::ncdirect_bg_rgb(ncd, rgb) }
 }

rust/src/macros.rs

@@ -31,3 +31,11 @@ macro_rules! cstring {
         std::ffi::CString::new($s).unwrap().as_ptr();
     };
 }
+
+/// Simple wrapper around [libc::printf].
+#[macro_export]
+macro_rules! printf {
+    ($s:expr) => {
+        unsafe { libc::printf(cstring![$s]) }
+    };
+}