效果如下：PDF导入的文件，PC版前台显示正常，但是手机版显示模糊。

处理方法：\content\_common\Base\js\power.js

                            var CSS_UNITS = 96.0 / 72.0;
                            var widthScale = viewport.height / viewport.width;
                            canvas.width = Math.floor(viewport.width * CSS_UNITS);
                            canvas.height = Math.floor(viewport.height * CSS_UNITS);

                            canvas.style.width = $("[data-power-area='content']").width() + "px";
                            canvas.style.height = Math.floor($("[data-power-area='content']").width() * widthScale) + "px";

                            
                            var renderContext = {
                                transform: [CSS_UNITS, 0, 0, CSS_UNITS, 0, 0],
                                canvasContext: ctx,
                                viewport: viewport
                            };