fix: 优化 README 内容问题，优化绘图

services/render.py

@@ -1,19 +1,22 @@
+import time
 from services.statistics import get_ammeter_left_ele, get_water_left
 from services.plot import plot_line
 
 
 async def render_ammeter_chart():
-    times, values = await get_ammeter_left_ele(limit=24)
+    times, left_ele, left_free_ele = await get_ammeter_left_ele(limit=24)
 
     if not times:
         return None
 
     out = "data/ammeter.png"
 
+    time_range = f"{time.strftime("%Y-%m-%d %H:%M", time.localtime(times[0] / 1000))} ～ {time.strftime("%Y-%m-%d %H:%M", time.localtime(times[-1] / 1000))}"
+
     plot_line(
-        times=times,
-        values=values,
-        title="宿舍电量剩余趋势",
+        times=[time.strftime("%H:%M", time.localtime(t / 1000)) for t in times],
+        normal_values=left_ele,
+        title=f"宿舍电量剩余趋势（{time_range}）",
         ylabel="剩余电量（度）",
         out_path=out,
     )
@@ -22,17 +25,19 @@ async def render_ammeter_chart():
 
 
 async def render_water_chart():
-    times, values = await get_water_left(limit=24)
+    times, left_water, left_free_water = await get_water_left(limit=24)
 
     if not times:
         return None
 
     out = "data/water.png"
 
+    time_range = f"{time.strftime("%Y-%m-%d %H:%M", time.localtime(times[0] / 1000))} ～ {time.strftime("%Y-%m-%d %H:%M", time.localtime(times[-1] / 1000))}"
+
     plot_line(
-        times=times,
-        values=values,
-        title="宿舍水量剩余趋势",
+        times=[time.strftime("%H:%M", time.localtime(t / 1000)) for t in times],
+        normal_values=left_water,
+        title=f"宿舍水量剩余趋势（{time_range}）",
         ylabel="剩余水量（吨）",
         out_path=out,
     )