添加 giftool 倒放选项

konabot/plugins/image_process/__init__.py

@@ -71,8 +71,11 @@ async def _(
         raise BotExceptionMessage("错误：出点时间小于入点")
     if frame_count is not None and frame_count <= 0:
         raise BotExceptionMessage("错误：帧数量应该大于 0")
-    if speed_factor <= 0:
-        raise BotExceptionMessage("错误：--speed 必须大于 0")
+    if speed_factor == 0:
+        raise BotExceptionMessage("错误：速度不能为 0")
+
+    is_rev = speed_factor < 0
+    speed_factor = abs(speed_factor)
 
     if not getattr(image, "is_animated", False):
         raise BotExceptionMessage("错误：输入的不是动图（GIF）")
@@ -185,6 +188,10 @@ async def _(
     if transparency_flag:
         tf['transparency'] = 0
 
+    if is_rev:
+        rframes = rframes[::-1]
+        rdur = rdur[::-1]
+
     if rframes:
         rframes[0].save(
             output_img,