feat(core/rust): added color constructor from rgba format, added text display functions using top-left coordinates

core/embed/rust/src/ui/display/mod.rs

@@ -1050,6 +1050,17 @@ impl Font {
 #[derive(Copy, Clone, PartialEq, Eq)]
 pub struct Color(u16);
 
+#[macro_export]
+macro_rules! alpha {
+    ($n: expr) => {
+        if ($n >= 1.0) {
+            256_u16
+        } else {
+            ($n * 256.0) as u16
+        }
+    };
+}
+
 impl Color {
     pub const fn from_u16(val: u16) -> Self {
         Self(val)
@@ -1063,11 +1074,26 @@ impl Color {
     }
 
     pub const fn luminance(self) -> u32 {
-        ((self.r() as u32 * 299) / 1000)
+        (self.r() as u32 * 299) / 1000
             + (self.g() as u32 * 587) / 1000
             + (self.b() as u32 * 114) / 1000
     }
 
+    pub const fn rgba(bg: Color, r: u8, g: u8, b: u8, alpha: u16) -> Self {
+        let r_u16 = r as u16;
+        let g_u16 = g as u16;
+        let b_u16 = b as u16;
+
+        let r = ((256 - alpha) * bg.r() as u16 + alpha * r_u16) >> 8;
+        let g = ((256 - alpha) * bg.g() as u16 + alpha * g_u16) >> 8;
+        let b = ((256 - alpha) * bg.b() as u16 + alpha * b_u16) >> 8;
+
+        let r = (r & 0xF8) << 8;
+        let g = (g & 0xFC) << 3;
+        let b = (b & 0xF8) >> 3;
+        Self(r | g | b)
+    }
+
     pub const fn r(self) -> u8 {
         (self.0 >> 8) as u8 & 0xF8
     }