使用openpyxl配置ChartLines对象时的网格线颜色异常问题

问题描述 #

使用openpyxl绘制折线图时，配置垂直网格线颜色不生效。代码中已设置黄色填充，但运行后网格线仍为默认颜色，仅刻度间隔（每4个刻度显示）符合预期。

示例代码 #

# Import 
from openpyxl import Workbook
from openpyxl.chart import LineChart, Reference
from openpyxl.chart.axis import ChartLines, TextAxis
from openpyxl.chart.shapes import GraphicalProperties
from openpyxl.drawing.colors import ColorChoice

# Create a line chart
chart = LineChart()

# Reference data from the worksheet I'm working with
num_rows = ws_data.max_row
num_cols = ws_data.max_column
data_ref = Reference(ws_data, min_col=2, min_row=1, max_col=num_cols, max_row=num_rows)
chart.add_data(data_ref, titles_from_data=True)

# Configure the x_axis
chart.x_axis = TextAxis(tickMarkSkip=4)
chart.x_axis.majorTickMark = "cross"
chart.x_axis.delete = False

# Configure the vertical gridlines
chart.x_axis.majorGridlines = ChartLines()
chart.x_axis.majorGridlines.graphicalProperties = GraphicalProperties(noFill=False, solidFill=ColorChoice(prstClr='yellow'))

# Add the chart to the 'Charts' worksheet
ws_chart.add_chart(chart, "A1")

解决方案 #

问题根源在于网格线的图形属性设置错误，openpyxl中线条样式需通过LineProperties定义，而非直接使用solidFill。修改网格线配置部分代码即可解决：

修改后的关键代码 #

# 新增必要导入
from openpyxl.chart.shapes import LineProperties
from openpyxl.drawing.colors import SchemeColor

# Configure the vertical gridlines
chart.x_axis.majorGridlines = ChartLines()
# 创建线条属性，设置颜色和宽度
line_props = LineProperties(solidFill=SchemeColor(prstClr='yellow'), w=1000)  # w为线条宽度，单位EMU
# 将线条属性传入GraphicalProperties的ln参数
chart.x_axis.majorGridlines.graphicalProperties = GraphicalProperties(ln=line_props)

完整修改后代码 #

from openpyxl import Workbook
from openpyxl.chart import LineChart, Reference
from openpyxl.chart.axis import ChartLines, TextAxis
from openpyxl.chart.shapes import GraphicalProperties, LineProperties
from openpyxl.drawing.colors import SchemeColor

# Create a line chart
chart = LineChart()

# Reference data from the worksheet I'm working with
num_rows = ws_data.max_row
num_cols = ws_data.max_column
data_ref = Reference(ws_data, min_col=2, min_row=1, max_col=num_cols, max_row=num_rows)
chart.add_data(data_ref, titles_from_data=True)

# Configure the x_axis
chart.x_axis = TextAxis(tickMarkSkip=4)
chart.x_axis.majorTickMark = "cross"
chart.x_axis.delete = False

# Configure the vertical gridlines
chart.x_axis.majorGridlines = ChartLines()
line_props = LineProperties(solidFill=SchemeColor(prstClr='yellow'), w=1000)
chart.x_axis.majorGridlines.graphicalProperties = GraphicalProperties(ln=line_props)

# Add the chart to the 'Charts' worksheet
ws_chart.add_chart(chart, "A1")

说明 #

• LineProperties用于定义线条的样式，包括颜色、宽度、虚线类型等
• 若需自定义颜色，可替换SchemeColor为RGBColor，传入RGB值（如RGBColor(255,255,0)表示黄色）
• w参数为线条宽度，单位是EMU（1pt=12700 EMU），设置为1000对应约0.08pt的细线

内容的提问来源于stack exchange，提问作者ensbana