From fd565429ac049006a49475e98cd37ccbcaf3c7ee Mon Sep 17 00:00:00 2001
From: Derek Atkins <derek@ihtfp.com>
Date: Tue, 27 May 2003 02:12:38 +0000
Subject: [PATCH] 	* src/register/ledger-core/dialog-dup-trans.c: If the
 "number" is 	  set to 0, then empty out the entry.  Considering the
 SpinButton 	  wants to force a digit, this lets you set an empty number if
 you 	  accidentally tab into and out of the number field.  This also 
   means you cannot have a check numbered '0', but that is probably 	  a
 reasonable limitation.  Fixes #109610.

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/branches/1.8@8412 57a11ea4-9604-0410-9ed3-97b8803252fd
---
 ChangeLog                                   |  7 +++
 src/register/ledger-core/dialog-dup-trans.c | 57 +++++++++++++++++++++
 2 files changed, 64 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index f973768878..d84dfaffcc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2003-05-26  Derek Atkins  <derek@ihtfp.com>
 
+	* src/register/ledger-core/dialog-dup-trans.c: If the "number" is
+	  set to 0, then empty out the entry.  Considering the SpinButton
+	  wants to force a digit, this lets you set an empty number if you
+	  accidentally tab into and out of the number field.  This also
+	  means you cannot have a check numbered '0', but that is probably
+	  a reasonable limitation.  Fixes #109610.
+
 	* src/business/business-core/gncInvoice.[ch]: define
 	  INVOICE_IS_PAID and create gncInvoiceIsPaid() function (the
 	  prototype already existed, but it was never implemented).
diff --git a/src/register/ledger-core/dialog-dup-trans.c b/src/register/ledger-core/dialog-dup-trans.c
index 80f65efa4d..b98b509942 100644
--- a/src/register/ledger-core/dialog-dup-trans.c
+++ b/src/register/ledger-core/dialog-dup-trans.c
@@ -40,6 +40,8 @@ typedef struct
 {
   GtkWidget * dialog;
 
+  gboolean focus_out;
+
   GtkWidget * date_edit;
   GtkWidget * num_edit;
 } DupTransDialog;
@@ -70,6 +72,56 @@ parse_num (const char *string, long int *num)
   return TRUE;
 }
 
+/*
+ * This code works around an annoying bug in the SpinButton -- as soon
+ * as you focus into the spin button it wants to force a digit to
+ * appear and there is nothing the user can do.  Once you focus in,
+ * the user cannot make the spin button entry be empty.
+ *
+ * To make matters worse, the spin button draws this number AFTER a
+ * focus-out event, so we can't just use that event to clear it out.
+ *
+ * To work around this problem we hook into two signals, focus-out and
+ * draw.  The focus-out event lets us know when we leave the
+ * spinbutton entry, and we set a flag to remember this fact, and also
+ * queue a redraw (just to be sure).  The draw event happens more
+ * frequently, but also happens after the spin button digitizes
+ * itself.  So when we hit a draw event we can check the flag and if
+ * it's set we can potentially empty out the entry.
+ *
+ * This also means you cannot have a check numbered "0", but that is
+ * probably a reasonable limitation.
+ */
+static void
+gnc_dup_trans_focus_out_cb (GtkSpinButton *button, GdkEventFocus *event,
+			    gpointer user_data)
+{
+  DupTransDialog *dt_dialog = user_data;
+
+  g_return_if_fail(GTK_IS_SPIN_BUTTON(button));
+  if (!dt_dialog) return;
+
+  dt_dialog->focus_out = TRUE;
+  gtk_widget_queue_draw(GTK_WIDGET(button));
+}
+
+static void
+gnc_dup_trans_draw_cb (GtkSpinButton *button, GdkRectangle *unused, gpointer data)
+{
+  DupTransDialog *dt_dialog = data;
+
+  g_return_if_fail(GTK_IS_SPIN_BUTTON(button));
+  if (!dt_dialog) return;
+
+  if (!dt_dialog->focus_out)
+    return;
+
+  dt_dialog->focus_out = FALSE;
+
+  if (!gtk_spin_button_get_value_as_int(button))
+    gtk_entry_set_text(GTK_ENTRY(button), "");
+}
+
 static void
 gnc_dup_trans_dialog_create (GtkWidget * parent, DupTransDialog *dt_dialog,
                              time_t date, const char *num_str)
@@ -112,6 +164,11 @@ gnc_dup_trans_dialog_create (GtkWidget * parent, DupTransDialog *dt_dialog,
     gnome_dialog_editable_enters (GNOME_DIALOG (dialog),
                                   GTK_EDITABLE (num_spin));
 
+    gtk_signal_connect (GTK_OBJECT(num_spin), "focus-out-event",
+			GTK_SIGNAL_FUNC(gnc_dup_trans_focus_out_cb), dt_dialog);
+    gtk_signal_connect (GTK_OBJECT(num_spin), "draw",
+			GTK_SIGNAL_FUNC(gnc_dup_trans_draw_cb), dt_dialog);
+
     if (num_str && parse_num (num_str, &num))
       gtk_spin_button_set_value (GTK_SPIN_BUTTON (num_spin), num + 1);
     else