feat: 二维码圆角风格 - 每个模块都是圆角矩形

- 白色背景圆角 8%
- 每个黑色模块圆角 30%
- 模块间有微小缝隙，更精致
- 自动裁剪 ZXing 空白边距

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/src/main/java/com/xiaoqu/watch/ui/bind/BindFragment.kt

@@ -86,35 +86,71 @@ class BindFragment : BaseFragment<FragmentBindBinding>() {
         }
     }
 
-    /** 将 ZXing BitMatrix 转换为圆角 Android Bitmap */
+    /**
+     * 将 ZXing BitMatrix 转换为圆角风格二维码 Bitmap
+     * 每个模块（小方块）都是圆角矩形，整体图片也是圆角
+     */
     private fun bitMatrixToBitmap(matrix: BitMatrix): Bitmap {
         val width = matrix.width
         val height = matrix.height
-        // 先生成方形 Bitmap
-        val pixels = IntArray(width * height)
+        val outputSize = 500  // 输出图片尺寸
+
+        val bitmap = Bitmap.createBitmap(outputSize, outputSize, Bitmap.Config.ARGB_8888)
+        val canvas = android.graphics.Canvas(bitmap)
+        val paint = android.graphics.Paint(android.graphics.Paint.ANTI_ALIAS_FLAG)
+
+        // 白色背景（圆角）
+        paint.color = 0xFFFFFFFF.toInt()
+        val bgRadius = outputSize * 0.08f
+        canvas.drawRoundRect(
+            android.graphics.RectF(0f, 0f, outputSize.toFloat(), outputSize.toFloat()),
+            bgRadius, bgRadius, paint
+        )
+
+        // 计算每个模块的尺寸和偏移
+        // 找到二维码实际内容的边界（去掉 ZXing 的空白边距）
+        var left = width; var top = height; var right = 0; var bottom = 0
         for (y in 0 until height) {
             for (x in 0 until width) {
-                pixels[y * width + x] = if (matrix[x, y]) {
-                    0xFF000000.toInt()  // 黑色模块
-                } else {
-                    0xFFFFFFFF.toInt()  // 白色背景
+                if (matrix[x, y]) {
+                    if (x < left) left = x
+                    if (x > right) right = x
+                    if (y < top) top = y
+                    if (y > bottom) bottom = y
                 }
             }
         }
-        val squareBitmap = Bitmap.createBitmap(pixels, width, height, Bitmap.Config.ARGB_8888)
+        val qrWidth = right - left + 1
+        val qrHeight = bottom - top + 1
 
-        // 绘制圆角
-        val output = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888)
-        val canvas = android.graphics.Canvas(output)
-        val paint = android.graphics.Paint(android.graphics.Paint.ANTI_ALIAS_FLAG)
-        val rect = android.graphics.RectF(0f, 0f, width.toFloat(), height.toFloat())
-        val radius = width * 0.12f  // 12% 圆角（参照 iPhone 风格）
-        canvas.drawRoundRect(rect, radius, radius, paint)
-        paint.xfermode = android.graphics.PorterDuffXfermode(android.graphics.PorterDuff.Mode.SRC_IN)
-        canvas.drawBitmap(squareBitmap, 0f, 0f, paint)
-        squareBitmap.recycle()
+        // 留出内边距
+        val padding = outputSize * 0.06f
+        val drawArea = outputSize - padding * 2
+        val moduleSize = drawArea / maxOf(qrWidth, qrHeight)
+        val offsetX = padding + (drawArea - qrWidth * moduleSize) / 2
+        val offsetY = padding + (drawArea - qrHeight * moduleSize) / 2
 
-        return output
+        // 绘制每个黑色模块为圆角矩形
+        paint.color = 0xFF000000.toInt()
+        val moduleRadius = moduleSize * 0.3f  // 每个模块 30% 圆角
+        val gap = moduleSize * 0.08f  // 模块间留小缝隙
+
+        for (y in top..bottom) {
+            for (x in left..right) {
+                if (matrix[x, y]) {
+                    val px = offsetX + (x - left) * moduleSize + gap
+                    val py = offsetY + (y - top) * moduleSize + gap
+                    val rect = android.graphics.RectF(
+                        px, py,
+                        px + moduleSize - gap * 2,
+                        py + moduleSize - gap * 2
+                    )
+                    canvas.drawRoundRect(rect, moduleRadius, moduleRadius, paint)
+                }
+            }
+        }
+
+        return bitmap
     }
 
     /**