Problem with setting value at which category axis intersect value axis

Question

I faced with problem with setting value at which category axis intersect value axis. Below a code sample

import time
import datetime


import traceback
import sys
from pptx import Presentation
from pptx.chart.data import ChartData
from pptx.enum.chart import XL_CHART_TYPE,XL_AXIS_CROSSES
from pptx.util import Inches
import pptx
from pptx import Presentation
from pptx.util import Cm, Pt
from pptx.enum.text import MSO_ANCHOR,MSO_VERTICAL_ANCHOR, MSO_AUTO_SIZE,PP_ALIGN
from pptx.chart.data import CategoryChartData, ChartData
from pptx.enum.chart import XL_CHART_TYPE
from pptx.enum.chart import XL_TICK_MARK, XL_MARKER_STYLE
from pptx.enum.chart import XL_LEGEND_POSITION
from pptx.dml.chtfmt import ChartFormat
from pptx.dml.line import LineFormat
from pptx.dml.color import ColorFormat, RGBColor
from pptx.enum.dml import MSO_LINE
prs = Presentation()
slide = prs.slides.add_slide(prs.slide_layouts[5])
chart_data = ChartData()


chart_data.categories = [datetime.datetime.strptime('2012-02-09', '%Y-%m-%d'), datetime.datetime.strptime('2012-04-09', '%Y-%m-%d'), datetime.datetime.strptime('2012-09-09', '%Y-%m-%d')]
chart_data.add_series('West',    (32.2, 28.4, 34.7))
chart_data.add_series('East',    (24.3, 30.6, 20.2))
chart_data.add_series('Midwest', (20.4, 18.3, 26.2))
x, y, cx, cy = Inches(2), Inches(2), Inches(6), Inches(4.5)
chart = slide.shapes.add_chart(
    XL_CHART_TYPE.LINE_MARKERS, x, y, cx, cy, chart_data
).chart
chart.has_legend = True
chart.legend.include_in_layout = False
chart.series[0].smooth = True
points = chart.plots[0].series[0].points
ccount = 1;
period = int(len(points)/1.0)
chart.plots[0].series[0].marker.style = XL_MARKER_STYLE.NONE
for point in points:
    if ccount== period:
        point.marker.style = 8
        fill = point.marker.format.fill
        fill.solid()
        fill.fore_color.rgb = RGBColor(*[0,0,0])
        point.marker.format.line.color.rgb = RGBColor(*[0,0,0])
        ccount = 1
    else:
        ccount +=1

try:
    chart.value_axis.crosses = XL_AXIS_CROSSES.MINIMUM
except Exception as error:
    traceback.print_exc()


chart.has_legend = True
chart.legend.include_in_layout = False
chart.legend.position = XL_LEGEND_POSITION.BOTTOM
chart.legend.font.size = Pt(6)

prs.save('chart-01.pptx')

Python iterpreter shows error like that:

Traceback (most recent call last): File "", line 56, in chart.value_axis.crosses = XL_AXIS_CROSSES.MINIMUM File "C:\Users*\AppData\Local\Continuum\anaconda3\lib\site-packages\pptx\chart\axis.py", line 433, in crosses cross_xAx = self._cross_xAx File "C:\Users*\AppData\Local\Continuum\anaconda3\lib\site-packages\pptx\chart\axis.py", line 512, in _cross_xAx cross_axId = self._element.xpath(expr)[0] IndexError: list index out of range

I think problem is working with datetime values within category axis. Because If I create this axis based on another type of object (string, float or int), all will be OK!

Any help would be appreciated!

The error message is incomplete. Please post the full stack trace. — scanny
Ok, I just edited the post and wrote my thoughts about the cause of the problem — EugenS

scanny scanny · Accepted Answer · 2018-09-13T14:23:36

Ok, this looks like it's a gap in the ValueAxis code that we missed when adding DateAxis a while back.

Try this. Add this function to your code somewhere convenient:

from ..enum.chart import XL_AXIS_CROSSES


def set_date_crosses(value_axis, value):
    """*value* is a member of XL_AXIS_CROSSES."""
    xAx = value_axis._elemement

    def _cross_xAx(self):
        """Axis element in same group (pri/sec) that crosses this axis."""
        crossAx_id = xAx.crossAx.val
        expr = (
            '(../c:catAx | ../c:valAx | ../c:dateAx)/c:axId[@val="%d"]'
            % crossAx_id
        )
        cross_axId = xAx.xpath(expr)[0]
        return cross_axId.getparent()

    cross_xAx = _cross_xAx()

    if value == XL_AXIS_CROSSES.CUSTOM:
        if cross_xAx.crossesAt is not None:
            return

    cross_xAx._remove_crosses()
    cross_xAx._remove_crossesAt()

    if value == XL_AXIS_CROSSES.CUSTOM:
        cross_xAx._add_crossesAt(val=0.0)
        return

    cross_xAx._add_crosses(val=value)

And then change chart.value_axis.crosses = XL_AXIS_CROSSES.MINIMUM to this:

set_date_crosses(chart.value_axis, XL_AXIS_CROSSES.MINIMUM)

And see if that does the trick.

If that works, let me know and I'll open a case to incorporate the change into the next version.

Problem with setting value at which category axis intersect value axis

1 Answers