Added support for chart line smoothing.

include/xlsxwriter/chart.h

@@ -724,6 +724,7 @@ typedef struct lxw_chart_series {
     lxw_chart_point *points;
     uint16_t point_count;
 
+    uint8_t smooth;
     uint8_t invert_if_negative;
 
     STAILQ_ENTRY (lxw_chart_series) list_pointers;
@@ -1333,6 +1334,8 @@ void chart_series_set_marker_pattern(lxw_chart_series *series,
 lxw_error chart_series_set_points(lxw_chart_series *series,
                                   lxw_chart_point *points[]);
 
+void chart_series_set_smooth(lxw_chart_series *series, uint8_t smooth);
+
 /**
  * @brief Set the name caption of the an axis.
  *
@@ -2334,7 +2337,6 @@ void chart_plotarea_set_pattern(lxw_chart *chart, lxw_chart_pattern *pattern);
  * to the base chart type. They can not be defined by the `chart_set_style()``
  * function.
  *
- *
  */
 void chart_set_style(lxw_chart *chart, uint8_t style_id);
 

src/chart.c

@@ -2070,14 +2070,16 @@ _chart_write_marker_value(lxw_chart *self)
  * Write the <c:smooth> element.
  */
 STATIC void
-_chart_write_smooth(lxw_chart *self)
+_chart_write_smooth(lxw_chart *self, uint8_t smooth)
 {
     struct xml_attribute_list attributes;
     struct xml_attribute *attribute;
-    char val[] = "1";
+
+    if (!smooth)
+        return;
 
     LXW_INIT_ATTRIBUTES();
-    LXW_PUSH_ATTRIBUTES_STR("val", val);
+    LXW_PUSH_ATTRIBUTES_STR("val", "1");
 
     lxw_xml_empty_tag(self->file, "c:smooth", &attributes);
 
@@ -2211,6 +2213,10 @@ _chart_write_ser(lxw_chart *self, lxw_chart_series *series)
     /* Write the c:val element. */
     _chart_write_val(self, series);
 
+    /* Write the c:smooth element. */
+    if (self->is_scatter_chart || self->type == LXW_CHART_LINE)
+        _chart_write_smooth(self, series->smooth);
+
     lxw_xml_end_tag(self->file, "c:ser");
 }
 
@@ -2249,11 +2255,8 @@ _chart_write_xval_ser(lxw_chart *self, lxw_chart_series *series)
     /* Write the yVal element. */
     _chart_write_y_val(self, series);
 
-    if (self->type == LXW_CHART_SCATTER_SMOOTH
-        || self->type == LXW_CHART_SCATTER_SMOOTH_WITH_MARKERS) {
-        /* Write the c:smooth element. */
-        _chart_write_smooth(self);
-    }
+    /* Write the c:smooth element. */
+    _chart_write_smooth(self, series->smooth);
 
     lxw_xml_end_tag(self->file, "c:ser");
 }
@@ -4000,6 +4003,12 @@ chart_add_series(lxw_chart *self, const char *categories, const char *values)
     if (_chart_init_data_cache(series->title.range) != LXW_NO_ERROR)
         goto mem_error;
 
+    if (self->type == LXW_CHART_SCATTER_SMOOTH)
+        series->smooth = LXW_TRUE;
+
+    if (self->type == LXW_CHART_SCATTER_SMOOTH_WITH_MARKERS)
+        series->smooth = LXW_TRUE;
+
     STAILQ_INSERT_TAIL(self->series_list, series, list_pointers);
 
     return series;
@@ -4272,6 +4281,15 @@ chart_series_set_points(lxw_chart_series *series, lxw_chart_point *points[])
     return LXW_NO_ERROR;
 }
 
+/*
+ * Set the smooth property for a line or scatter series.
+ */
+void
+chart_series_set_smooth(lxw_chart_series *series, uint8_t smooth)
+{
+    series->smooth = smooth;
+}
+
 /*
  * Set an axis caption.
  */

test/functional/src/test_chart_line03.c

@@ -0,0 +1,44 @@
+/*****************************************************************************
+ * 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_line03.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 = 47673728;
+    chart->axis_id_2 = 47675264;
+
+    uint8_t data[5][3] = {
+        {5, 10, 15},
+        {2, 4,  6 },
+        {3, 6,  9 },
+        {4, 8,  12},
+        {3, 6,  9 }
+    };
+
+    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 *series = chart_add_series(chart, NULL, "=Sheet1!$A$1:$A$5");
+    chart_add_series(chart, NULL, "=Sheet1!$B$1:$B$5");
+    chart_add_series(chart, NULL, "=Sheet1!$C$1:$C$5");
+
+    chart_series_set_smooth(series, LXW_TRUE);
+
+    worksheet_insert_chart(worksheet, CELL("E9"), chart);
+
+    return workbook_close(workbook);
+}

test/functional/src/test_chart_line04.c

@@ -0,0 +1,45 @@
+/*****************************************************************************
+ * 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_line04.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 = 47670016;
+    chart->axis_id_2 = 47671552;
+
+    uint8_t data[5][3] = {
+        {5, 10, 15},
+        {2, 4,  6 },
+        {3, 6,  9 },
+        {4, 8,  12},
+        {3, 6,  9 }
+    };
+
+    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, NULL, "=Sheet1!$A$1:$A$5");
+    chart_add_series(chart, NULL, "=Sheet1!$B$1:$B$5");
+    lxw_chart_series *series3 = chart_add_series(chart, NULL, "=Sheet1!$C$1:$C$5");
+
+    chart_series_set_smooth(series1, LXW_TRUE);
+    chart_series_set_smooth(series3, LXW_TRUE);
+
+    worksheet_insert_chart(worksheet, CELL("E9"), chart);
+
+    return workbook_close(workbook);
+}

test/functional/src/test_chart_scatter09.c

@@ -0,0 +1,50 @@
+/*****************************************************************************
+ * 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_scatter09.xlsx");
+    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
+    lxw_chart     *chart     = workbook_add_chart(workbook, LXW_CHART_SCATTER_SMOOTH_WITH_MARKERS);
+
+    /* For testing, copy the randomly generated axis ids in the target file. */
+    chart->axis_id_1 = 45953024;
+    chart->axis_id_2 = 45954944;
+
+    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 *series = 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"
+    );
+
+    chart_series_set_smooth(series, LXW_FALSE);
+
+    worksheet_insert_chart(worksheet, CELL("E9"), chart);
+
+    return workbook_close(workbook);
+}

test/functional/src/test_chart_scatter10.c

@@ -0,0 +1,50 @@
+/*****************************************************************************
+ * 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_scatter10.xlsx");
+    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
+    lxw_chart     *chart     = workbook_add_chart(workbook, LXW_CHART_SCATTER_SMOOTH);
+
+    /* For testing, copy the randomly generated axis ids in the target file. */
+    chart->axis_id_1 = 84754816;
+    chart->axis_id_2 = 84756352;
+
+    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);
+
+    chart_add_series(chart,
+         "=Sheet1!$A$1:$A$5",
+         "=Sheet1!$B$1:$B$5"
+    );
+
+    lxw_chart_series *series = chart_add_series(chart,
+         "=Sheet1!$A$1:$A$5",
+         "=Sheet1!$C$1:$C$5"
+    );
+
+    chart_series_set_smooth(series, LXW_FALSE);
+
+    worksheet_insert_chart(worksheet, CELL("E9"), chart);
+
+    return workbook_close(workbook);
+}

test/functional/src/test_chart_scatter11.c

@@ -0,0 +1,50 @@
+/*****************************************************************************
+ * 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_scatter11.xlsx");
+    lxw_worksheet *worksheet = workbook_add_worksheet(workbook, NULL);
+    lxw_chart     *chart     = workbook_add_chart(workbook, LXW_CHART_SCATTER_STRAIGHT_WITH_MARKERS);
+
+    /* For testing, copy the randomly generated axis ids in the target file. */
+    chart->axis_id_1 = 47439232;
+    chart->axis_id_2 = 47670400;
+
+    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 *series = 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"
+    );
+
+    chart_series_set_smooth(series, LXW_TRUE);
+
+    worksheet_insert_chart(worksheet, CELL("E9"), chart);
+
+    return workbook_close(workbook);
+}

test/functional/test_chart_line.py

@@ -15,3 +15,9 @@ class TestCompareXLSXFiles(base_test_class.XLSXBaseTest):
 
     def test_chart_line01(self):
         self.run_exe_test('test_chart_line01')
+
+    def test_chart_line03(self):
+        self.run_exe_test('test_chart_line03')
+
+    def test_chart_line04(self):
+        self.run_exe_test('test_chart_line04')

test/functional/test_chart_scatter.py

@@ -31,6 +31,15 @@ class TestCompareXLSXFiles(base_test_class.XLSXBaseTest):
     def test_chart_scatter06(self):
         self.run_exe_test('test_chart_scatter06')
 
+    def test_chart_scatter09(self):
+        self.run_exe_test('test_chart_scatter09')
+
+    def test_chart_scatter10(self):
+        self.run_exe_test('test_chart_scatter10')
+
+    def test_chart_scatter11(self):
+        self.run_exe_test('test_chart_scatter11')
+
     def test_chart_scatter12(self):
         self.run_exe_test('test_chart_scatter12')