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chart_doughnut.c
<< chart_pie.c chart_clustered.c >>

Example of creating an Excel Doughnut chart.

The default doughnut chart:

chart_doughnut1.png

It is possible to define chart colors for most types of libxlsxwriter charts via the series formatting functions. However, Pie/Doughnut charts are a special case since each segment is represented as a point so it is necessary to assign formatting to each point in the series.

Chart 4 shows how to set segment colors and other options.

chart_doughnut2.png
/*
* An example of creating an Excel doughnut chart using the libxlsxwriter library.
*
* The demo also shows how to set segment colors. It is possible to define
* chart colors for most types of libxlsxwriter charts via the series
* formatting functions. However, Pie/Doughnut charts are a special case since
* each segment is represented as a point so it is necessary to assign
* formatting to each point in the series.
*
* Copyright 2014-2017, John McNamara, jmcnamara@cpan.org
*
*/
#include "xlsxwriter.h"
/*
* Write some data to the worksheet.
*/
void write_worksheet_data(lxw_worksheet *worksheet, lxw_format *bold) {
worksheet_write_string(worksheet, CELL("A1"), "Category", bold);
worksheet_write_string(worksheet, CELL("A2"), "Glazed", NULL);
worksheet_write_string(worksheet, CELL("A3"), "Chocolate", NULL);
worksheet_write_string(worksheet, CELL("A4"), "Cream", NULL);
worksheet_write_string(worksheet, CELL("B1"), "Values", bold);
worksheet_write_number(worksheet, CELL("B2"), 50, NULL);
worksheet_write_number(worksheet, CELL("B3"), 35, NULL);
worksheet_write_number(worksheet, CELL("B4"), 15, NULL);
}
/*
* Create a worksheet with examples charts.
*
*/
int main() {
lxw_workbook *workbook = new_workbook("chart_doughnut.xlsx");
lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
lxw_chart *chart ;
/* Add a bold format to use to highlight the header cells. */
lxw_format *bold = workbook_add_format(workbook);
/* Write some data for the chart. */
write_worksheet_data(worksheet, bold);
/*
* Chart 1: Create a simple doughnut chart.
*/
/* Add the first series to the chart. */
series = chart_add_series(chart, "=Sheet1!$A$2:$A$4", "=Sheet1!$B$2:$B$4");
/* Set the name for the series instead of the default "Series 1". */
chart_series_set_name(series, "Doughnut sales data");
/* Add a chart title. */
chart_title_set_name(chart, "Popular Doughnut Types");
/* Set an Excel chart style. */
chart_set_style(chart, 10);
/* Insert the chart into the worksheet. */
worksheet_insert_chart(worksheet, CELL("D2"), chart);
/*
* Chart 2: Create a doughnut chart with user defined segment colors.
*/
/* Add the first series to the chart. */
series = chart_add_series(chart, "=Sheet1!$A$2:$A$4", "=Sheet1!$B$2:$B$4");
/* Set the name for the series instead of the default "Series 1". */
chart_series_set_name(series, "Doughnut sales data");
/* Add a chart title. */
chart_title_set_name(chart, "Doughnut Chart with user defined colors");
/* Add for fills for use in the chart. */
lxw_chart_fill fill1 = {.color = 0xFA58D0};
lxw_chart_fill fill2 = {.color = 0x61210B};
lxw_chart_fill fill3 = {.color = 0xF5F6CE};
/* Add some points with the above fills. */
lxw_chart_point point1 = {.fill = &fill1};
lxw_chart_point point2 = {.fill = &fill2};
lxw_chart_point point3 = {.fill = &fill3};
/* Create an array of the point objects. */
lxw_chart_point *points[] = {&point1,
&point2,
&point3,
NULL};
/* Add/override the points/segments of the chart. */
chart_series_set_points(series, points);
/* Insert the chart into the worksheet. */
worksheet_insert_chart(worksheet, CELL("D18"), chart);
/*
* Chart 3: Create a Doughnut chart with rotation of the segments.
*/
/* Add the first series to the chart. */
series = chart_add_series(chart, "=Sheet1!$A$2:$A$4", "=Sheet1!$B$2:$B$4");
/* Set the name for the series instead of the default "Series 1". */
chart_series_set_name(series, "Doughnut sales data");
/* Add a chart title. */
chart_title_set_name(chart, "Doughnut Chart with segment rotation");
/* Change the angle/rotation of the first segment. */
chart_set_rotation(chart, 90);
/* Insert the chart into the worksheet. */
worksheet_insert_chart(worksheet, CELL("D34"), chart);
/*
* Chart 4: Create a Doughnut chart with user defined hole size and other
* options.
*/
/* Add the first series to the chart. */
series = chart_add_series(chart, "=Sheet1!$A$2:$A$4", "=Sheet1!$B$2:$B$4");
/* Set the name for the series instead of the default "Series 1". */
chart_series_set_name(series, "Doughnut sales data");
/* Add a chart title. */
chart_title_set_name(chart, "Doughnut Chart with options applied.");
/* Add/override the points/segments defined in Chart 2. */
chart_series_set_points(series, points);
/* Set an Excel chart style. */
chart_set_style(chart, 26);
/* Change the angle/rotation of the first segment. */
chart_set_rotation(chart, 28);
/* Change the hole size. */
chart_set_hole_size(chart, 33);
/* Insert the chart into the worksheet. */
worksheet_insert_chart(worksheet, CELL("D50"), chart);
return workbook_close(workbook);
}