Initial chart error bars.

.indent.pro

@@ -54,6 +54,9 @@
 -T lxw_chart_axis_tick_mark
 -T lxw_chart_axis_tick_position
 -T lxw_chart_blank
+-T lxw_chart_error_bar_cap
+-T lxw_chart_error_bar_direction
+-T lxw_chart_error_bar_type
 -T lxw_chart_fill
 -T lxw_chart_font
 -T lxw_chart_gridline
@@ -108,6 +111,7 @@
 -T lxw_row_t
 -T lxw_selection
 -T lxw_series_data_point
+-T lxw_series_error_bar
 -T lxw_series_range
 -T lxw_sst
 -T lxw_styles

include/xlsxwriter/chart.h

@@ -569,28 +569,6 @@ typedef enum lxw_chart_axis_tick_mark {
     LXW_CHART_AXIS_TICK_MARK_CROSSING
 } lxw_chart_tick_mark;
 
-/**
- * @brief Define how blank values are displayed in a chart.
- */
-typedef enum lxw_chart_blank {
-
-    /** Show empty chart cells as gaps in the data. The default. */
-    LXW_CHART_BLANKS_AS_GAP,
-
-    /** Show empty chart cells as zeros. */
-    LXW_CHART_BLANKS_AS_ZERO,
-
-    /** Show empty chart cells as connected. Only for charts with lines. */
-    LXW_CHART_BLANKS_AS_CONNECTED
-} lxw_chart_blank;
-
-enum lxw_chart_position {
-    LXW_CHART_AXIS_RIGHT,
-    LXW_CHART_AXIS_LEFT,
-    LXW_CHART_AXIS_TOP,
-    LXW_CHART_AXIS_BOTTOM
-};
-
 typedef struct lxw_series_range {
     char *formula;
     char *sheetname;
@@ -776,6 +754,81 @@ typedef struct lxw_chart_point {
 
 } lxw_chart_point;
 
+/**
+ * @brief Define how blank values are displayed in a chart.
+ */
+typedef enum lxw_chart_blank {
+
+    /** Show empty chart cells as gaps in the data. The default. */
+    LXW_CHART_BLANKS_AS_GAP,
+
+    /** Show empty chart cells as zeros. */
+    LXW_CHART_BLANKS_AS_ZERO,
+
+    /** Show empty chart cells as connected. Only for charts with lines. */
+    LXW_CHART_BLANKS_AS_CONNECTED
+} lxw_chart_blank;
+
+enum lxw_chart_position {
+    LXW_CHART_AXIS_RIGHT,
+    LXW_CHART_AXIS_LEFT,
+    LXW_CHART_AXIS_TOP,
+    LXW_CHART_AXIS_BOTTOM
+};
+
+/**
+ * @brief Type/amount of data series error bar.
+ */
+typedef enum lxw_chart_error_bar_type {
+    /** Error bar type: Standard error. */
+    LXW_CHART_ERROR_BAR_TYPE_STD_ERROR,
+
+    /** Error bar type: Fixed value. */
+    LXW_CHART_ERROR_BAR_TYPE_FIXED,
+
+    /** Error bar type: Percentage. */
+    LXW_CHART_ERROR_BAR_TYPE_PERCENTAGE,
+
+    /** Error bar type: Standard deviation(s). */
+    LXW_CHART_ERROR_BAR_TYPE_STD_DEV
+} lxw_chart_error_bar_type;
+
+/**
+ * @brief Direction for a data series error bar.
+ */
+typedef enum lxw_chart_error_bar_direction {
+
+    /** Error bar extends in both directions. The default. */
+    LXW_CHART_ERROR_BAR_DIR_BOTH,
+
+    /** Error bar extends in positive direction. */
+    LXW_CHART_ERROR_BAR_DIR_PLUS,
+
+    /** Error bar extends in negative direction. */
+    LXW_CHART_ERROR_BAR_DIR_MINUS
+} lxw_chart_error_bar_direction;
+
+/**
+ * @brief End cap styles for a data series error bar.
+ */
+typedef enum lxw_chart_error_bar_cap {
+    /** Flat end cap. The default. */
+    LXW_CHART_ERROR_BAR_END_CAP,
+
+    /** No end cap. */
+    LXW_CHART_ERROR_BAR_NO_CAP
+} lxw_chart_error_bar_cap;
+
+typedef struct lxw_series_error_bar {
+    uint8_t type;
+    uint8_t direction;
+    uint8_t endcap;
+    uint8_t has_value;
+    double value;
+    lxw_chart_line *line;
+
+} lxw_series_error_bar;
+
 /**
  * @brief Struct to represent an Excel chart data series.
  *
@@ -812,6 +865,11 @@ typedef struct lxw_chart_series {
     char *label_num_format;
     lxw_chart_font *label_font;
 
+    lxw_series_error_bar x_error_bar;
+    lxw_series_error_bar y_error_bar;
+    uint8_t has_x_error_bar;
+    uint8_t has_y_error_bar;
+
     STAILQ_ENTRY (lxw_chart_series) list_pointers;
 
 } lxw_chart_series;
@@ -1699,6 +1757,9 @@ void chart_series_set_labels_num_format(lxw_chart_series *series,
 void chart_series_set_labels_font(lxw_chart_series *series,
                                   lxw_chart_font *font);
 
+void chart_series_set_y_error_bars_line(lxw_chart_series *series,
+                                        lxw_chart_line *line);
+
 /**
  * @brief Set the name caption of the an axis.
  *

src/chart.c

@@ -110,6 +110,9 @@ _chart_series_free(lxw_chart_series *series)
     _chart_free_range(series->title.range);
     _chart_free_points(series);
 
+    free(series->x_error_bar.line);
+    free(series->y_error_bar.line);
+
     free(series);
 }
 
@@ -2239,6 +2242,161 @@ _chart_write_d_lbls(lxw_chart *self, lxw_chart_series *series)
     lxw_xml_end_tag(self->file, "c:dLbls");
 }
 
+/*
+ * Write the <c:val> element.
+ */
+STATIC void
+_chart_write_error_val(lxw_chart *self, double value)
+{
+    struct xml_attribute_list attributes;
+    struct xml_attribute *attribute;
+
+    LXW_INIT_ATTRIBUTES();
+    LXW_PUSH_ATTRIBUTES_DBL("val", value);
+
+    lxw_xml_empty_tag(self->file, "c:val", &attributes);
+
+    LXW_FREE_ATTRIBUTES();
+}
+
+/*
+ * Write the <c:noEndCap> element.
+ */
+STATIC void
+_chart_write_no_end_cap(lxw_chart *self)
+{
+    struct xml_attribute_list attributes;
+    struct xml_attribute *attribute;
+
+    LXW_INIT_ATTRIBUTES();
+    LXW_PUSH_ATTRIBUTES_STR("val", "1");
+
+    lxw_xml_empty_tag(self->file, "c:noEndCap", &attributes);
+
+    LXW_FREE_ATTRIBUTES();
+}
+
+/*
+ * Write the <c:errValType> element.
+ */
+STATIC void
+_chart_write_err_val_type(lxw_chart *self, uint8_t type)
+{
+    struct xml_attribute_list attributes;
+    struct xml_attribute *attribute;
+
+    LXW_INIT_ATTRIBUTES();
+
+    if (type == LXW_CHART_ERROR_BAR_TYPE_FIXED)
+        LXW_PUSH_ATTRIBUTES_STR("val", "fixedVal");
+    else if (type == LXW_CHART_ERROR_BAR_TYPE_PERCENTAGE)
+        LXW_PUSH_ATTRIBUTES_STR("val", "percentage");
+    else if (type == LXW_CHART_ERROR_BAR_TYPE_STD_DEV)
+        LXW_PUSH_ATTRIBUTES_STR("val", "stdDev");
+    else
+        LXW_PUSH_ATTRIBUTES_STR("val", "stdErr");
+
+    lxw_xml_empty_tag(self->file, "c:errValType", &attributes);
+
+    LXW_FREE_ATTRIBUTES();
+}
+
+/*
+ * Write the <c:errBarType> element.
+ */
+STATIC void
+_chart_write_err_bar_type(lxw_chart *self, uint8_t direction)
+{
+    struct xml_attribute_list attributes;
+    struct xml_attribute *attribute;
+
+    LXW_INIT_ATTRIBUTES();
+
+    if (direction == LXW_CHART_ERROR_BAR_DIR_PLUS)
+        LXW_PUSH_ATTRIBUTES_STR("val", "plus");
+    else if (direction == LXW_CHART_ERROR_BAR_DIR_MINUS)
+        LXW_PUSH_ATTRIBUTES_STR("val", "minus");
+    else
+        LXW_PUSH_ATTRIBUTES_STR("val", "both");
+
+    lxw_xml_empty_tag(self->file, "c:errBarType", &attributes);
+
+    LXW_FREE_ATTRIBUTES();
+}
+
+/*
+ * Write the <c:errDir> element.
+ */
+STATIC void
+_chart_write_err_dir(lxw_chart *self, uint8_t vertical)
+{
+    struct xml_attribute_list attributes;
+    struct xml_attribute *attribute;
+
+    LXW_INIT_ATTRIBUTES();
+
+    if (vertical)
+        LXW_PUSH_ATTRIBUTES_STR("val", "y");
+    else
+        LXW_PUSH_ATTRIBUTES_STR("val", "n");
+
+    lxw_xml_empty_tag(self->file, "c:errDir", &attributes);
+
+    LXW_FREE_ATTRIBUTES();
+}
+
+/*
+ * Write the <c:errBars> element.
+ */
+STATIC void
+_chart_write_err_bars(lxw_chart *self, uint8_t vertical,
+                      lxw_chart_series *series)
+{
+    lxw_series_error_bar *error_bar;
+
+    if (vertical)
+        error_bar = &series->y_error_bar;
+    else
+        error_bar = &series->x_error_bar;
+
+    lxw_xml_start_tag(self->file, "c:errBars", NULL);
+
+    /* Write the c:errDir element. */
+    _chart_write_err_dir(self, vertical);
+
+    /* Write the c:errBarType element. */
+    _chart_write_err_bar_type(self, error_bar->direction);
+
+    /* Write the c:errValType element. */
+    _chart_write_err_val_type(self, error_bar->type);
+
+    /* Write the c:noEndCap element. */
+    if (error_bar->endcap == LXW_CHART_ERROR_BAR_NO_CAP)
+        _chart_write_no_end_cap(self);
+
+    /* Write the c:val element. */
+    if (error_bar->has_value)
+        _chart_write_error_val(self, error_bar->value);
+
+    /* Write the c:spPr element. */
+    _chart_write_sp_pr(self, error_bar->line, NULL, NULL);
+
+    lxw_xml_end_tag(self->file, "c:errBars");
+}
+
+/*
+ * Write the <c:errBars> element.
+ */
+STATIC void
+_chart_write_error_bars(lxw_chart *self, lxw_chart_series *series)
+{
+    if (series->has_x_error_bar)
+        _chart_write_err_bars(self, LXW_FALSE, series);
+
+    if (series->has_y_error_bar)
+        _chart_write_err_bars(self, LXW_TRUE, series);
+}
+
 /*
  * Write the <c:size> element.
  */
@@ -2450,6 +2608,9 @@ _chart_write_ser(lxw_chart *self, lxw_chart_series *series)
     /* Write the c:dLbls element. */
     _chart_write_d_lbls(self, series);
 
+    /* Write the c:errBars element. */
+    _chart_write_error_bars(self, series);
+
     /* Write the c:cat element. */
     _chart_write_cat(self, series);
 
@@ -2495,6 +2656,9 @@ _chart_write_xval_ser(lxw_chart *self, lxw_chart_series *series)
     /* Write the c:dLbls element. */
     _chart_write_d_lbls(self, series);
 
+    /* Write the c:errBars element. */
+    _chart_write_error_bars(self, series);
+
     /* Write the c:xVal element. */
     _chart_write_x_val(self, series);
 
@@ -4947,6 +5111,22 @@ chart_series_set_labels_font(lxw_chart_series *series, lxw_chart_font *font)
     series->label_font = _chart_convert_font_args(font);
 }
 
+/*
+ * Set a line type for a series marker.
+ */
+void
+chart_series_set_y_error_bars_line(lxw_chart_series *series,
+                                   lxw_chart_line *line)
+{
+    if (!line)
+        return;
+
+    /* Free any previously allocated resource. */
+    free(series->y_error_bar.line);
+
+    series->y_error_bar.line = _chart_convert_line_args(line);
+}
+
 /*
  * Set an axis caption.
  */

test/functional/src/test_chart_errorbars01.c

@@ -0,0 +1,51 @@
+/*****************************************************************************
+ * Test cases for libxlsxwriter.
+ *
+ * Test to compare output against Excel files.
+ *
+ * Copyright 2014-2017, John McNamara, jmcnamara@cpan.org
+ *
+ */
+
+#include "xlsxwriter.h"
+
+int main() {
+
+    lxw_workbook  *workbook  = new_workbook("test_chart_errorbars01.xlsx");
+    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
+    lxw_chart     *chart     = workbook_add_chart(workbook, LXW_CHART_LINE);
+
+    /* For testing, copy the randomly generated axis ids in the target file. */
+    chart->axis_id_1 = 63386752;
+    chart->axis_id_2 = 63388288;
+
+    uint8_t data[5][3] = {
+        {1, 2,  3},
+        {2, 4,  6},
+        {3, 6,  9},
+        {4, 8,  12},
+        {5, 10, 15}
+    };
+
+    int row, col;
+    for (row = 0; row < 5; row++)
+        for (col = 0; col < 3; col++)
+            worksheet_write_number(worksheet, row, col, data[row][col], NULL);
+
+    lxw_chart_series *series1 = chart_add_series(chart,
+         "=Sheet1!$A$1:$A$5",
+         "=Sheet1!$B$1:$B$5"
+    );
+
+    chart_add_series(chart,
+         "=Sheet1!$A$1:$A$5",
+         "=Sheet1!$C$1:$C$5"
+    );
+
+
+    series1->has_y_error_bar = 1;
+
+    worksheet_insert_chart(worksheet, CELL("E9"), chart);
+
+    return workbook_close(workbook);
+}

test/functional/src/test_chart_errorbars02.c

@@ -0,0 +1,62 @@
+/*****************************************************************************
+ * Test cases for libxlsxwriter.
+ *
+ * Test to compare output against Excel files.
+ *
+ * Copyright 2014-2017, John McNamara, jmcnamara@cpan.org
+ *
+ */
+
+#include "xlsxwriter.h"
+
+int main() {
+
+    lxw_workbook  *workbook  = new_workbook("test_chart_errorbars02.xlsx");
+    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
+    lxw_chart     *chart     = workbook_add_chart(workbook, LXW_CHART_LINE);
+
+    /* For testing, copy the randomly generated axis ids in the target file. */
+    chart->axis_id_1 = 63385984;
+    chart->axis_id_2 = 63387904;
+
+    uint8_t data[5][3] = {
+        {1, 2,  3},
+        {2, 4,  6},
+        {3, 6,  9},
+        {4, 8,  12},
+        {5, 10, 15}
+    };
+
+    int row, col;
+    for (row = 0; row < 5; row++)
+        for (col = 0; col < 3; col++)
+            worksheet_write_number(worksheet, row, col, data[row][col], NULL);
+
+    lxw_chart_series *series1 = chart_add_series(chart,
+         "=Sheet1!$A$1:$A$5",
+         "=Sheet1!$B$1:$B$5"
+    );
+
+    lxw_chart_series *series2 = chart_add_series(chart,
+         "=Sheet1!$A$1:$A$5",
+         "=Sheet1!$C$1:$C$5"
+    );
+
+    series1->has_y_error_bar = 1;
+    series1->y_error_bar.type = LXW_CHART_ERROR_BAR_TYPE_FIXED;
+    series1->y_error_bar.direction = LXW_CHART_ERROR_BAR_DIR_MINUS;
+    series1->y_error_bar.endcap = LXW_CHART_ERROR_BAR_NO_CAP;
+    series1->y_error_bar.has_value = 1;
+    series1->y_error_bar.value = 2;
+
+    series2->has_y_error_bar = 1;
+    series2->y_error_bar.type = LXW_CHART_ERROR_BAR_TYPE_PERCENTAGE;
+    series2->y_error_bar.direction = LXW_CHART_ERROR_BAR_DIR_PLUS;
+    series2->y_error_bar.endcap = LXW_CHART_ERROR_BAR_END_CAP;
+    series2->y_error_bar.has_value = 1;
+    series2->y_error_bar.value = 5;
+
+    worksheet_insert_chart(worksheet, CELL("E9"), chart);
+
+    return workbook_close(workbook);
+}

test/functional/src/test_chart_errorbars03.c

@@ -0,0 +1,56 @@
+/*****************************************************************************
+ * Test cases for libxlsxwriter.
+ *
+ * Test to compare output against Excel files.
+ *
+ * Copyright 2014-2017, John McNamara, jmcnamara@cpan.org
+ *
+ */
+
+#include "xlsxwriter.h"
+
+int main() {
+
+    lxw_workbook  *workbook  = new_workbook("test_chart_errorbars03.xlsx");
+    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
+    lxw_chart     *chart     = workbook_add_chart(workbook, LXW_CHART_LINE);
+
+    /* For testing, copy the randomly generated axis ids in the target file. */
+    chart->axis_id_1 = 52288896;
+    chart->axis_id_2 = 53605504;
+
+    uint8_t data[5][3] = {
+        {1, 2,  3},
+        {2, 4,  6},
+        {3, 6,  9},
+        {4, 8,  12},
+        {5, 10, 15}
+    };
+
+    int row, col;
+    for (row = 0; row < 5; row++)
+        for (col = 0; col < 3; col++)
+            worksheet_write_number(worksheet, row, col, data[row][col], NULL);
+
+    lxw_chart_series *series1 = chart_add_series(chart,
+         "=Sheet1!$A$1:$A$5",
+         "=Sheet1!$B$1:$B$5"
+    );
+
+    chart_add_series(chart,
+         "=Sheet1!$A$1:$A$5",
+         "=Sheet1!$C$1:$C$5"
+    );
+
+
+    lxw_chart_line line = {.color     = LXW_COLOR_RED,
+                           .dash_type = LXW_CHART_LINE_DASH_ROUND_DOT};
+
+    series1->has_y_error_bar = 1;
+    series1->y_error_bar.type = LXW_CHART_ERROR_BAR_TYPE_STD_ERROR;
+    chart_series_set_y_error_bars_line(series1, &line);
+
+    worksheet_insert_chart(worksheet, CELL("E9"), chart);
+
+    return workbook_close(workbook);
+}

test/functional/test_chart_errorbars.py

@@ -0,0 +1,23 @@
+###############################################################################
+#
+# Tests for libxlsxwriter.
+#
+# Copyright 2014-2017, John McNamara, jmcnamara@cpan.org
+#
+
+import base_test_class
+
+class TestCompareXLSXFiles(base_test_class.XLSXBaseTest):
+    """
+    Test file created with libxlsxwriter against a file created by Excel.
+
+    """
+
+    def test_chart_errorbars01(self):
+        self.run_exe_test('test_chart_errorbars01')
+
+    def test_chart_errorbars02(self):
+        self.run_exe_test('test_chart_errorbars02')
+
+    def test_chart_errorbars03(self):
+        self.run_exe_test('test_chart_errorbars03')