Allow dia database shapes to change start arrow type

dia-0.97.2-dbarrow-optional.patch

diff --git a/objects/Database/reference.c b/objects/Database/reference.c
index 616d106..562c1dd 100644
--- a/objects/Database/reference.c
+++ b/objects/Database/reference.c
@@ -107,7 +107,8 @@ static PropDescription reference_props[] =
     PROP_STD_LINE_STYLE_OPTIONAL,
     { "corner_radius", PROP_TYPE_REAL, PROP_FLAG_VISIBLE,
       N_("Corner radius"), NULL, &reference_corner_radius_data },
-    PROP_STD_START_ARROW,
+    { "start_arrow", PROP_TYPE_ARROW, PROP_FLAG_VISIBLE|PROP_FLAG_STANDARD|PROP_FLAG_OPTIONAL, \
+      N_("Start arrow"), NULL, NULL }
     PROP_STD_END_ARROW,
     { "start_point_desc", PROP_TYPE_STRING, PROP_FLAG_VISIBLE,
       N_("Start description"), NULL, NULL },

dia-0.97.2-dbarrow.patch

From a0f297b004109da16d72260288aacb0762fdaf7c Mon Sep 17 00:00:00 2001
From: Jim Ursetto <jim@3e8.org>
Date: Sun, 22 Apr 2012 23:58:18 -0500
Subject: [PATCH] Add start_arrow attribute to database table reference object

---
 objects/Database/database.h  |    1 +
 objects/Database/reference.c |    5 ++++-
 2 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/objects/Database/database.h b/objects/Database/database.h
index f7fda38..42e4f33 100644
--- a/objects/Database/database.h
+++ b/objects/Database/database.h
@@ -146,6 +146,7 @@ struct _TableReference {
 
   gchar * start_point_desc;
   gchar * end_point_desc;
+  Arrow start_arrow;
   Arrow end_arrow;
   real corner_radius;
 
diff --git a/objects/Database/reference.c b/objects/Database/reference.c
index 891a6e2..616d106 100644
--- a/objects/Database/reference.c
+++ b/objects/Database/reference.c
@@ -107,6 +107,7 @@ static PropDescription reference_props[] =
     PROP_STD_LINE_STYLE_OPTIONAL,
     { "corner_radius", PROP_TYPE_REAL, PROP_FLAG_VISIBLE,
       N_("Corner radius"), NULL, &reference_corner_radius_data },
+    PROP_STD_START_ARROW,
     PROP_STD_END_ARROW,
     { "start_point_desc", PROP_TYPE_STRING, PROP_FLAG_VISIBLE,
       N_("Start description"), NULL, NULL },
@@ -131,6 +132,7 @@ static PropOffset reference_offsets[] =
     { PROP_STDNAME_LINE_WIDTH, PROP_STDTYPE_LINE_WIDTH, offsetof(TableReference, line_width) },
     { "line_style", PROP_TYPE_LINESTYLE, offsetof(TableReference, line_style),
       offsetof(TableReference, dashlength) },
+    { "start_arrow", PROP_TYPE_ARROW, offsetof(TableReference, start_arrow) },
     { "end_arrow", PROP_TYPE_ARROW, offsetof(TableReference, end_arrow) },
     { "corner_radius", PROP_TYPE_REAL, offsetof(TableReference, corner_radius) },
     { "normal_font", PROP_TYPE_FONT, offsetof(TableReference, normal_font) },
@@ -183,6 +185,7 @@ reference_create (Point *startpoint,
   attributes_get_default_line_style (&ref->line_style, &ref->dashlength);
   ref->text_color = color_black;
   ref->line_color = attributes_get_foreground ();
+  ref->start_arrow = attributes_get_default_start_arrow ();
   ref->end_arrow = attributes_get_default_end_arrow ();
   ref->corner_radius = 0.0;
   ref->start_point_desc = g_strdup ("1");
@@ -232,7 +235,7 @@ reference_draw (TableReference *ref, DiaRenderer *renderer)
 
   renderer_ops->draw_rounded_polyline_with_arrows
     (renderer, points, num_points, ref->line_width,
-     &ref->line_color, NULL, &ref->end_arrow, ref->corner_radius);
+     &ref->line_color, &ref->start_arrow, &ref->end_arrow, ref->corner_radius);
 
   renderer_ops->set_font (renderer, ref->normal_font, ref->normal_font_height);
 
-- 
1.7.6.1

Second ("optional") patch makes start arrow attribute optional so warnings don't occur on load.

But either way, if missing, the start arrow is taken from the toolbox at load time. Alternatively if we force the start arrow to NULL in the creation function, you can never set a default in the toolbox.

Unfortunately there doesn't seem to be any way to set a separate "default if missing" value.