feat: optimize slogan animation with smooth color interpolation

Implemented true color interpolation for buttery smooth gradient animation:
- Added hexToRgb, rgbToHex, and interpolateColor functions for mathematical color blending
- Increased frame rate from 24 to 60 FPS for ultra-smooth motion
- Changed easing from cubic to sine wave for more natural transitions
- Dynamically generate gradients per frame instead of using pre-defined set
- Eliminates staggered/jumping effect in the slogan text animation

The animation now uses real-time color interpolation between adjacent colors
in the sequence, creating seamless transitions without visible steps.

Author: m1ngsama

src/core/logo.ts

@@ -25,27 +25,103 @@ function createBlueGradient(text: string): string {
 }
 
 /**
- * 显示渐变动画效果（优化版 - 更丝滑的动画）
+ * 将十六进制颜色转换为RGB
+ */
+function hexToRgb(hex: string): [number, number, number] {
+  const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
+  return result
+    ? [parseInt(result[1]!, 16), parseInt(result[2]!, 16), parseInt(result[3]!, 16)]
+    : [0, 0, 0];
+}
+
+/**
+ * 将RGB转换为十六进制颜色
+ */
+function rgbToHex(r: number, g: number, b: number): string {
+  return '#' + [r, g, b].map(x => {
+    const hex = Math.round(x).toString(16);
+    return hex.length === 1 ? '0' + hex : hex;
+  }).join('');
+}
+
+/**
+ * 在两个颜色之间进行线性插值
+ */
+function interpolateColor(color1: string, color2: string, factor: number): string {
+  const [r1, g1, b1] = hexToRgb(color1);
+  const [r2, g2, b2] = hexToRgb(color2);
+
+  const r = r1 + (r2 - r1) * factor;
+  const g = g1 + (g2 - g1) * factor;
+  const b = b1 + (b2 - b1) * factor;
+
+  return rgbToHex(r, g, b);
+}
+
+/**
+ * 缓动函数 - 平滑的进出效果
+ */
+function easeInOutSine(t: number): number {
+  return -(Math.cos(Math.PI * t) - 1) / 2;
+}
+
+/**
+ * 显示渐变动画效果（优化版 - 真正丝滑的动画）
  */
 async function animateGradient(text: string, duration: number = 1200): Promise<void> {
-  const frames = 24; // 增加帧数使动画更流畅
+  const frames = 60; // 60帧实现真正的流畅动画
   const frameDelay = duration / frames;
 
-  // 预创建所有渐变对象
-  const gradients = [
-    gradient('#1e3a8a', '#2563eb', '#3b82f6'),
-    gradient('#2563eb', '#3b82f6', '#0ea5e9'),
-    gradient('#3b82f6', '#0ea5e9', '#06b6d4'),
-    gradient('#0ea5e9', '#06b6d4', '#14b8a6'),
-    gradient('#06b6d4', '#14b8a6', '#0ea5e9'),
-    gradient('#14b8a6', '#0ea5e9', '#3b82f6'),
-    gradient('#0ea5e9', '#3b82f6', '#2563eb'),
-    gradient('#3b82f6', '#2563eb', '#1e3a8a'),
+  // 定义颜色序列 - 形成完整的蓝色系循环
+  const colorSequence = [
+    '#1e3a8a', // 深蓝
+    '#2563eb', // 蓝
+    '#3b82f6', // 亮蓝
+    '#0ea5e9', // 天蓝
+    '#06b6d4', // 青色
+    '#14b8a6', // 青绿
+    '#06b6d4', // 青色
+    '#0ea5e9', // 天蓝
+    '#3b82f6', // 亮蓝
+    '#2563eb', // 蓝
+    '#1e3a8a', // 深蓝
   ];
 
   for (let i = 0; i < frames; i++) {
-    const gradientIndex = Math.floor((i / frames) * gradients.length);
-    const frameGradient = gradients[gradientIndex]!;
+    // 使用平滑的正弦缓动
+    const progress = easeInOutSine(i / frames);
+
+    // 计算在颜色序列中的位置
+    const position = progress * (colorSequence.length - 1);
+    const index1 = Math.floor(position);
+    const index2 = Math.min(index1 + 1, colorSequence.length - 1);
+    const localProgress = position - index1;
+
+    // 在相邻颜色间插值，生成三个平滑过渡的颜色
+    const color1 = interpolateColor(
+      colorSequence[index1]!,
+      colorSequence[index2]!,
+      localProgress
+    );
+
+    const nextIndex1 = Math.min(index2, colorSequence.length - 1);
+    const nextIndex2 = Math.min(nextIndex1 + 1, colorSequence.length - 1);
+    const color2 = interpolateColor(
+      colorSequence[nextIndex1]!,
+      colorSequence[nextIndex2]!,
+      localProgress
+    );
+
+    const nextIndex3 = Math.min(nextIndex2, colorSequence.length - 1);
+    const nextIndex4 = Math.min(nextIndex3 + 1, colorSequence.length - 1);
+    const color3 = interpolateColor(
+      colorSequence[nextIndex3]!,
+      colorSequence[nextIndex4]!,
+      localProgress
+    );
+
+    // 为当前帧创建渐变
+    const frameGradient = gradient(color1, color2, color3);
 
     // 清除当前行并显示新帧
     process.stdout.write('\r' + frameGradient(text));