[gnumeric] xlsx: save a view3D for contour plots.

[Morten Welinder <mortenw src gnome org>]

commit 57e64db4c04e9a9102aa8856b8f210ec0710e5e0
Author: Morten Welinder <terra gnome org>
Date:   Thu Oct 26 15:36:26 2017 -0400

    xlsx: save a view3D for contour plots.
    
    A 3D view for a 2D plot.  XL needs it.

 NEWS                               |    1 +
 plugins/excel/ChangeLog            |    3 ++-
 plugins/excel/xlsx-write-drawing.c |   36 ++++++++++++++++++++++++++++++------
 3 files changed, 33 insertions(+), 7 deletions(-)
---
diff --git a/NEWS b/NEWS
index d6063d4..c3aa360 100644
--- a/NEWS
+++ b/NEWS
@@ -13,6 +13,7 @@ Morten:
        * Minor CORREL improvement.
        * Fix error on xlsx files with bogus Print_Area.
        * xlsx import improvements for contour graphs.
+       * xlsx export improvements for contour graphs.
 
 --------------------------------------------------------------------------
 Gnumeric 1.12.35
diff --git a/plugins/excel/ChangeLog b/plugins/excel/ChangeLog
index ed505f6..afca323 100644
--- a/plugins/excel/ChangeLog
+++ b/plugins/excel/ChangeLog
@@ -1,7 +1,8 @@
 2017-10-26  Morten Welinder  <terra gnome org>
 
        * xlsx-write-drawing.c (xlsx_write_axis): Make axis tag for
-       surface charts match what XL wants.  Even if it isn't obvious why.
+       contour charts match what XL wants.  Even if it isn't obvious why.
+       (xlsx_write_one_chart): Save a view3D for contour charts.
 
 2017-10-24  Morten Welinder  <terra gnome org>
 
diff --git a/plugins/excel/xlsx-write-drawing.c b/plugins/excel/xlsx-write-drawing.c
index 2d5d905..3512860 100644
--- a/plugins/excel/xlsx-write-drawing.c
+++ b/plugins/excel/xlsx-write-drawing.c
@@ -1233,14 +1233,13 @@ xlsx_write_one_plot (XLSXWriteState *state, GsfXMLOut *xml,
 }
 
 static void
-xlsx_write_plots (XLSXWriteState *state, GsfXMLOut *xml, GogObject const *chart, int *ser_count)
+xlsx_write_plots (XLSXWriteState *state, GsfXMLOut *xml, GogObject const *chart,
+                 GSList *plots, int *ser_count)
 {
-       GSList *plots, *l;
-       GogObjectRole const *role = gog_object_find_role_by_name (GOG_OBJECT (chart), "Plot");
+       GSList *l;
        GHashTable *axis_to_plot = g_hash_table_new (NULL, NULL);
        GSList *axes = NULL;
 
-       plots = gog_object_get_children (GOG_OBJECT (chart), role);
        for (l = plots; l; l = l->next) {
                GogPlot *plot = l->data;
                GSList *plot_axes, *al;
@@ -1255,7 +1254,6 @@ xlsx_write_plots (XLSXWriteState *state, GsfXMLOut *xml, GogObject const *chart,
                }
                g_slist_free (plot_axes);
        }
-       g_slist_free (plots);
 
        for (l = axes; l; l = l->next) {
                GogAxis *axis = l->data;
@@ -1273,6 +1271,9 @@ xlsx_write_one_chart (XLSXWriteState *state, GsfXMLOut *xml, GogObject const *ch
 {
        GogObject const *obj;
        int ser_count = 0;
+       GogObjectRole const *role;
+       GSList *plots, *l;
+       gboolean done;
 
        gsf_xml_out_start_element (xml, "c:chart");
 
@@ -1286,10 +1287,32 @@ xlsx_write_one_chart (XLSXWriteState *state, GsfXMLOut *xml, GogObject const *ch
                }
        }
 
+       role = gog_object_find_role_by_name (GOG_OBJECT (chart), "Plot");
+       plots = gog_object_get_children (GOG_OBJECT (chart), role);
+
+       for (l = plots, done = FALSE; l && !done; l = l->next) {
+               GogPlot *plot = l->data;
+               const char *plot_type_name = G_OBJECT_TYPE_NAME (plot);
+               XLSXPlotType plot_type = xlsx_plottype_from_type_name (plot_type_name);
+               switch (plot_type) {
+               case XLSX_PT_GOGCONTOURPLOT:
+               case XLSX_PT_XLCONTOURPLOT:
+                       // XL wants a 3D view for a 2D chart
+                       gsf_xml_out_start_element (xml, "c:view3D");
+                       xlsx_write_chart_float (xml, "c:rotX", 90);
+                       xlsx_write_chart_float (xml, "c:rotY", 0);
+                       xlsx_write_chart_float (xml, "c:rAngAx", 0);
+                       xlsx_write_chart_float (xml, "c:perspective", 0);
+                       gsf_xml_out_end_element (xml);
+                       done = TRUE;
+                       break;
+               }
+       }
+
        gsf_xml_out_start_element (xml, "c:plotArea");
        /* save grid style here */
 
-       xlsx_write_plots (state, xml, chart, &ser_count);
+       xlsx_write_plots (state, xml, chart, plots, &ser_count);
 
        obj = gog_object_get_child_by_name (GOG_OBJECT (chart), "Backplane");
        if (obj) {
@@ -1302,6 +1325,7 @@ xlsx_write_one_chart (XLSXWriteState *state, GsfXMLOut *xml, GogObject const *ch
        }
 
        gsf_xml_out_end_element (xml); /* </c:plotArea> */
+       g_slist_free (plots);
 
        if ((obj = gog_object_get_child_by_name (chart, "Legend"))) {
                char const *str;