Add support for gradients

Signed-off-by: Joe Grund <[email protected]>

Author: jgrund

examples/gradient.rs

@@ -0,0 +1,55 @@
+use console::{style, Color, Style};
+
+fn main() {
+    // Basic foreground gradient using the builder API
+    println!(
+        "Foreground gradient: {}",
+        style("Hello, gradient world!")
+            .fg(Color::TrueColor(255, 0, 0))
+            .fg_end(Color::TrueColor(0, 0, 255))
+    );
+
+    // Background gradient
+    println!(
+        "Background gradient: {}",
+        style("  Rainbow background  ")
+            .bg(Color::TrueColor(255, 0, 0))
+            .bg_end(Color::TrueColor(0, 255, 0))
+    );
+
+    // Both foreground and background gradients
+    println!(
+        "Both gradients: {}",
+        style("Fancy text!")
+            .fg(Color::TrueColor(255, 255, 0))
+            .fg_end(Color::TrueColor(255, 0, 255))
+            .bg(Color::TrueColor(0, 0, 128))
+            .bg_end(Color::TrueColor(0, 128, 0))
+    );
+
+    // Using from_dotted_str for gradient specification
+    let gradient_style = Style::from_dotted_str("#ff0000->#00ff00.bold");
+    println!(
+        "From dotted string: {}",
+        gradient_style.apply_to("Styled from_dotted_str")
+    );
+
+    // Gradient with named colors (they get converted to RGB for interpolation)
+    println!(
+        "Named color gradient: {}",
+        style("Red to Blue").fg(Color::Red).fg_end(Color::Blue)
+    );
+
+    // Progress bar simulation
+    let width = 40;
+    let progress = 0.7; // 70% complete
+    let filled = (width as f32 * progress) as usize;
+    let bar: String = "█".repeat(filled) + &"░".repeat(width - filled);
+    println!(
+        "Progress: [{}] {}%",
+        style(&bar)
+            .fg(Color::TrueColor(0, 255, 0))
+            .fg_end(Color::TrueColor(0, 128, 255)),
+        (progress * 100.0) as u32
+    );
+}