PyChartDirector中文教程[8]：饼图的图例

May 18	PyChartDirector中文教程[8]：饼图的图例
	Categories: Python \| Tags: ChartDirector, Python \| Views: 3,254

上节我们说了标签，这节我们来说图例：

先看图

这个例子不仅展示了图例的显示，也展示了标签的样式的设定和饼图边缘阴影化。

－图例增加通过：BaseChart.addLegend

－改变标签样式使用：PieChart.setLabelFormat

－增加边缘阴影：PieChart.setSectorStyle

代码：

#!/usr/bin/python
from pychartdir import *
 
# The data for the pie chart
data = [25, 18, 15, 12, 8, 30, 35]
 
# The labels for the pie chart
labels = ["Labor", "Licenses", "Taxes", "Legal", "Insurance", "Facilities",
    "Production"]
 
# Create a PieChart object of size 450 x 270 pixels
c = PieChart(450, 270)
 
# Set the center of the pie at (150, 100) and the radius to 80 pixels
c.setPieSize(150, 135, 100)
 
# add a legend box where the top left corner is at (330, 50)
c.addLegend(330, 60)
 
# modify the sector label format to show percentages only
c.setLabelFormat("{percent}%")
 
# Set the pie data and the pie labels
c.setData(data, labels)
 
# Use rounded edge shading, with a 1 pixel white (FFFFFF) border
c.setSectorStyle(RoundedEdgeShading, 0xffffff, 1)
 
# Output the chart
c.makeChart("legendpie.png")

我们再来看看更为复杂一点的图例：

我们看看这张图有些什么效果：背景颜色渐变、圆角图例框、软阴影、自定义区域颜色、区域阴影渐变、用CDML自定义区域标签、格式化的图例文字

－背景颜色渐变：BaseChart.linearGradientColor

－圆角图例框：BaseChart.setRoundedFrame

－软阴影：BaseChart.setDropShadow

－区域自定义颜色：BaseChart.setColors

－区域渐变阴影：PieChart.setSectorStyle

－自定义区域标签：PieChart.setLabelFormat（设置序号）、PieChart.setLabelStyle（设置样式）、Box.setBackground（标签加框）

－图例文字设置：用LegendBox的TextBox.setText，图例文字模板是用如下CDML描述的：

<*block,valign=top*>{={sector}+1}.<*advanceTo=22*><*block,width=120*>{label}<*/*><*block,width=40,halign=right*>{percent}<*/*>%

<*block,valign=top*> 表示图例中不同的部分都顶端对齐，这样图例第二部分可以多行显示

{={sector}+1}.<*advanceTo=22*> 显示序号，并TAB到22px的位置（sector从0开始，所以要+1）

<*block,width=120*>{label}<*/*> 在120px长的block中显示标签，如果标签文字长于120px，则多行显示

<*block,width=40,halign=right*>{percent}<*/*>% 在40px长的block中显示百分比，并右对齐

代码：

#!/usr/bin/python
from pychartdir import *
 
# The data for the pie chart
data = [21, 18, 15, 12, 8, 24]
 
# The labels for the pie chart
labels = ["Labor", "Licenses", "Taxes", "Legal", "Facilities", "Production"]
 
# The colors to use for the sectors
colors = [0x66aaee, 0xeebb22, 0xbbbbbb, 0x8844ff, 0xdd2222, 0x009900]
 
# Create a PieChart object of size 600 x 320 pixels. Use a vertical gradient color
# from light blue (99ccff) to white (ffffff) spanning the top 100 pixels as
# background. Set border to grey (888888). Use rounded corners. Enable soft drop
# shadow.
c = PieChart(600, 320)
c.setBackground(c.linearGradientColor(0, 0, 0, 100, 0x99ccff, 0xffffff), 0x888888)
c.setRoundedFrame()
c.setDropShadow()
 
# Add a title using 18 pts Times New Roman Bold Italic font. Add 16 pixels top margin
# to the title.
c.addTitle("Pie Chart With Legend Demonstration", "timesbi.ttf", 18).setMargin2(0, 0,
    16, 0)
 
# Set the center of the pie at (160, 165) and the radius to 110 pixels
c.setPieSize(160, 165, 110)
 
# Draw the pie in 3D with a pie thickness of 25 pixels
c.set3D(25)
 
# Set the pie data and the pie labels
c.setData(data, labels)
 
# Set the sector colors
c.setColors2(DataColor, colors)
 
# Use local gradient shading for the sectors
c.setSectorStyle(LocalGradientShading)
 
# Use the side label layout method, with the labels positioned 16 pixels from the pie
# bounding box
c.setLabelLayout(SideLayout, 16)
 
# Show only the sector number as the sector label
c.setLabelFormat("{={sector}+1}")
 
# Set the sector label style to Arial Bold 10pt, with a dark grey (444444) border
c.setLabelStyle("arialbd.ttf", 10).setBackground(Transparent, 0x444444)
 
# Add a legend box, with the center of the left side anchored at (330, 175), and
# using 10 pts Arial Bold Italic font
b = c.addLegend(330, 175, 1, "arialbi.ttf", 10)
b.setAlignment(Left)
 
# Set the legend box border to dark grey (444444), and with rounded conerns
b.setBackground(Transparent, 0x444444)
b.setRoundedCorners()
 
# Set the legend box margin to 16 pixels, and the extra line spacing between the
# legend entries as 5 pixels
b.setMargin(16)
b.setKeySpacing(0, 5)
 
# Set the legend box icon to have no border (border color same as fill color)
b.setKeyBorder(SameAsMainColor)
 
# Set the legend text to show the sector number, followed by a 120 pixels wide block
# showing the sector label, and a 40 pixels wide block showing the percentage
b.setText(
    "<*block,valign=top*>{={sector}+1}.<*advanceTo=22*><*block,width=120*>{label}" \
    "<*/*><*block,width=40,halign=right*>{percent}<*/*>%")
 
# Output the chart
c.makeChart("legendpie2.png")