fix 图表主题plotBackgroundColor为transparent时,生成的图表背景色全黑

src/views/ppt_manage/mixins/pptMixins.js

@@ -855,11 +855,13 @@ export default {
                 })
             let  parser = new DOMParser();
             let svgDoc = parser.parseFromString(svgData, 'image/svg+xml');
-
+            //console.log('plotBackgroundColor',plotBackgroundColor)
             // 查找class为'background'的rect元素并修改fill属性
             let rectElement = svgDoc.querySelector('rect.highcharts-plot-background');
             if (rectElement) {
-                rectElement.setAttribute('fill', plotBackgroundColor);
+                //transparent(生成的图表背景会变黑) -> rgba(255, 255, 255, 0)
+                let currentColor = plotBackgroundColor==='transparent'?'rgba(255, 255, 255, 0)':plotBackgroundColor
+                rectElement.setAttribute('fill', currentColor);
             }
             // 将修改后的SVG文档转换回字符串
             let serializer = new XMLSerializer();