Renders an Apache ECharts doughnut chart (pie chart with a hollow centre).
ECHARTSDOUGHNUT — set as ReportType in def_report.
def Render(self, Param1="", Param2="", Param3="") -> str:
Inherited from ObjReportEchartsbase. Param1, Param2, and Param3 are forwarded in the RPC payload for SQL token substitution. Returns an HTML string containing a styled panel and an ECharts initialisation script.
Uses the Apache ECharts JS library. Sets self.Type = "pie" and self.Doughnut = True, which causes ObjReportEchartsbase._build_pie_option to use a ring radius of ["45%", "70%"]. The SQL query must return rows with two columns: label and numeric value.