再调整对比色算法

src/jlgraphic/plugins/CommonMousePlugin.ts

@@ -101,13 +101,26 @@ export class CommonMouseTool extends AppInteractionPlugin {
     return new CommonMouseTool(app);
   }
 
+  /**
+   * 计算对比色
+   * @param rgb
+   * @returns
+   */
+  private calContrastColor(rgb: number): number {
+    if (rgb > 0.45 && rgb < 0.55) {
+      return 0;
+    } else {
+      return 1 - rgb;
+    }
+  }
+
   private updateBoxLineColor(cp: ICanvasProperties) {
     // 根据画布背景调整线色
     const color = new Color(cp.backgroundColor);
     // 对比色
-    const r = 1 - color.red;
-    const g = 1 - color.green;
-    const b = 1 - color.blue;
+    const r = this.calContrastColor(color.red);
+    const g = this.calContrastColor(color.green);
+    const b = this.calContrastColor(color.blue);
     this._boxLineColor.setValue([r, g, b]);
   }