* add scaleLineHeight option to pie chart and update document file.

docs/part/view-chart.md

@@ -427,6 +427,9 @@ var myDoughnutChart = $("#myDoughnutChart").doughnutChart(data, {segmentShowStro
     // 'auto' - 自动决定显示位置
     scaleLabelPlacement: "auto",
 
+    // Number - 标签行高
+    scaleLineHeight: 1,
+
     //Number - 动画执行总步数
     animationSteps : 60,
 

src/js/Chart.Doughnut.js

@@ -242,7 +242,7 @@
                     x = Math.min(chartWidthHalf - segment.outerRadius - 10, x - 30 + chartWidthHalf);
                 }
 
-                var textHeight = options.scaleFontSize;
+                var textHeight = options.scaleFontSize * (options.scaleLineHeight || 1);
                 var labelPos = Math.round((y * 0.8 + chartHeightHalf) / textHeight) + 1;
                 var maxPos = Math.floor(this.chart.width / textHeight) + 1;
                 var labelPosDirection = isRight ? 1 : (-1);