[gnumeric] Improve chart placement in xlsx export

[Andreas J. Guelzow <guelzow src gnome org>]

commit 1a52e32b440742d97d66e6fea0814cd0ba522a09
Author: Andreas J. Guelzow <aguelzow pyrshep ca>
Date:   Fri Apr 18 19:51:12 2014 -0600

    Improve chart placement in xlsx export
    
    2014-04-18  Andreas J. Guelzow <aguelzow pyrshep ca>
    
        * xlsx-write-drawing.c (xlsx_pts_to_emu): new
        (xlsx_write_object_anchor): add offset arguments
        (xlsx_write_objects): pass offsets to xlsx_write_object_anchor

 plugins/excel/ChangeLog            |    6 ++++++
 plugins/excel/xlsx-write-drawing.c |   24 +++++++++++++++++++-----
 2 files changed, 25 insertions(+), 5 deletions(-)
---
diff --git a/plugins/excel/ChangeLog b/plugins/excel/ChangeLog
index 633cfc7..f2fef1e 100644
--- a/plugins/excel/ChangeLog
+++ b/plugins/excel/ChangeLog
@@ -1,3 +1,9 @@
+2014-04-18  Andreas J. Guelzow <aguelzow pyrshep ca>
+
+       * xlsx-write-drawing.c (xlsx_pts_to_emu): new
+       (xlsx_write_object_anchor): add offset arguments
+       (xlsx_write_objects): pass offsets to xlsx_write_object_anchor
+
 2014-04-17  Morten Welinder  <terra gnome org>
 
        * xlsx-read-drawing.c (xlsx_chart_gridlines): Handle minorgrid
diff --git a/plugins/excel/xlsx-write-drawing.c b/plugins/excel/xlsx-write-drawing.c
index 9d6eddf..3c77bd8 100644
--- a/plugins/excel/xlsx-write-drawing.c
+++ b/plugins/excel/xlsx-write-drawing.c
@@ -461,14 +461,24 @@ xlsx_write_chart (XLSXWriteState *state, GsfOutput *chart_part, SheetObject *so)
        g_object_unref (xml);
 }
 
+static int
+xlsx_pts_to_emu (double pts)
+{
+       return (double) gnm_floor (12700. * pts);
+}
+
 static void
-xlsx_write_object_anchor (GsfXMLOut *xml, GnmCellPos const *pos, char const *element)
+xlsx_write_object_anchor (GsfXMLOut *xml, GnmCellPos const *pos, char const *element, double col_off_pts, 
double row_off_pts)
 {
+       /* For some reason we are using this additional scaling factor when we read!? */
+       /* FIXME: scaling horizontally just like in xlsx_CT_Col */
        gsf_xml_out_start_element (xml, element);
        gsf_xml_out_simple_int_element (xml, "xdr:col", pos->col);
-       gsf_xml_out_simple_int_element (xml, "xdr:colOff", 0);
+       gsf_xml_out_simple_int_element (xml, "xdr:colOff", 
+                                       xlsx_pts_to_emu (col_off_pts * 1.16191275167785));
        gsf_xml_out_simple_int_element (xml, "xdr:row", pos->row);
-       gsf_xml_out_simple_int_element (xml, "xdr:rowOff", 0);
+       gsf_xml_out_simple_int_element (xml, "xdr:rowOff",
+                                       xlsx_pts_to_emu (row_off_pts));
        gsf_xml_out_end_element (xml);
 }
 
@@ -482,6 +492,7 @@ xlsx_write_objects (XLSXWriteState *state, GsfOutput *sheet_part, GSList *object
        GsfOutput *drawing_part, *chart_part;
        GsfXMLOut *xml;
        SheetObjectAnchor const *anchor;
+       double res_pts[4] = {0.,0.,0.,0.};
 
        if (NULL == state->drawing.dir)
                state->drawing.dir = (GsfOutfile *)gsf_outfile_new_child (state->xl_dir, "drawings", TRUE);
@@ -522,10 +533,13 @@ xlsx_write_objects (XLSXWriteState *state, GsfOutput *sheet_part, GSList *object
        chart_id = g_slist_reverse (chart_ids);
        for (obj = objects; obj != NULL ; obj = obj->next, chart_id = chart_id->next) {
                anchor = sheet_object_get_anchor (obj->data);
+               sheet_object_anchor_to_offset_pts (anchor, state->sheet, res_pts);
 
                gsf_xml_out_start_element (xml, "xdr:twoCellAnchor");
-               xlsx_write_object_anchor (xml, &anchor->cell_bound.start, "xdr:from");
-               xlsx_write_object_anchor (xml, &anchor->cell_bound.end, "xdr:to");
+               xlsx_write_object_anchor (xml, &anchor->cell_bound.start, "xdr:from",
+                                         res_pts[0], res_pts[1]);
+               xlsx_write_object_anchor (xml, &anchor->cell_bound.end, "xdr:to",
+                                         res_pts[2], res_pts[3]);
 
                gsf_xml_out_start_element (xml, "xdr:graphicFrame");
                gsf_xml_out_add_cstr_unchecked (xml, "macro", "");