增加逐个导出时使用自动时长

SpineViewer/Exporter/Implementations/ExportArgs/VideoExportArgs.cs

@@ -17,14 +17,27 @@ namespace SpineViewer.Exporter.Implementations.ExportArgs
         /// <summary>
         /// 导出时长
         /// </summary>
-        [Category("视频参数"), DisplayName("时长"), Description("可以从模型列表查看动画时长")]
+        [Category("视频参数"), DisplayName("时长"), Description("可以从模型列表查看动画时长, 如果小于 0, 则在逐个导出时每个模型使用各自的当前动画时长")]
-        public float Duration { get => duration; set => duration = Math.Max(0, value); }
+        public float Duration 
-        private float duration = 1;
+        { 
+            get => duration;
+            set => duration = value < 0 ? -1 : value;
+        }
+        private float duration = -1;
 
         /// <summary>
         /// 帧率
         /// </summary>
         [Category("视频参数"), DisplayName("帧率"), Description("每秒画面数")]
         public float FPS { get; set; } = 60;
+
+        public override string? Validate()
+        {
+            if (base.Validate() is string error)
+                return error;
+            if (ExportSingle && Duration < 0)
+                return "导出单个时导出时长不能为负数";
+            return null;
+        }
     }
 }

SpineViewer/Exporter/Implementations/Exporter/VideoExporter.cs

@@ -22,8 +22,13 @@ namespace SpineViewer.Exporter.Implementations.Exporter
         protected IEnumerable<SFMLImageVideoFrame> GetFrames(Spine.Spine spine, BackgroundWorker? worker = null)
         {
             var args = (VideoExportArgs)ExportArgs;
+
+            // 独立导出时如果 args.Duration 小于 0 则使用自己的动画时长
+            var duration = args.Duration;
+            if (duration < 0) duration = spine.GetAnimationDuration(spine.CurrentAnimation);
+
             float delta = 1f / args.FPS;
-            int total = 1 + (int)(args.Duration * args.FPS); // 至少导出 1 帧
+            int total = Math.Max(1, (int)(duration * args.FPS)); // 至少导出 1 帧
 
             worker?.ReportProgress(0, $"{spine.Name} 已处理 0/{total} 帧");
             for (int i = 0; i < total; i++)
@@ -46,9 +51,10 @@ namespace SpineViewer.Exporter.Implementations.Exporter
         /// </summary>
         protected IEnumerable<SFMLImageVideoFrame> GetFrames(Spine.Spine[] spinesToRender, BackgroundWorker? worker = null)
         {
+            // 导出单个时必须根据 args.Duration 决定导出时长
             var args = (VideoExportArgs)ExportArgs;
             float delta = 1f / args.FPS;
-            int total = 1 + (int)(args.Duration * args.FPS); // 至少导出 1 帧
+            int total = Math.Max(1, (int)(args.Duration * args.FPS)); // 至少导出 1 帧
 
             worker?.ReportProgress(0, $"已处理 0/{total} 帧");
             for (int i = 0; i < total; i++)