Bug#508042: newt frontent have inefficient use of screen real estate (multiselect)

[Nicolas François <nicolas.francois@centraliens.net>]

Hello,

I had a look at other cdebconf newt frontend bugs in the BTS and it looks
like the second issue (cdebconf_newt_need_separate_window.patch) is the
same as:
 http://bugs.debian.org/507372
 http://bugs.debian.org/343119

Jérémy provided a patch in 507372, based on the same idea of using
get_full_description().
It was mentioned by Frans that it is incomplete, but fortunately the other
bytes in cdebconf_newt_need_separate_window.patch fix the issue
completely.
(At least I cannot reproduce the bug after trying many different window
height)

Also, as Jérémy, I forgot to free the result of get_full_description() in
my first patch.

So here is an updated version, which free the result and document that the
result of get_full_description shall be freed by the caller.

Best Regards,
-- 
Nekral

This fix the computation and usage of the window's height. If the height
is not computed correctly, the newt frontend may decide to put the input
box and the explanatory text on the same window, but the text will overlap
on the input box, which render the input impossible.
#508042 is an example for a multiselect, although I think it could appear
with a select window (not for string and password windows because I think
the input field is always forced to be on the same window).

	* src/modules/frontend/newt/newt.c (min_window_height): Document
	the computation of the window's height.
	* src/modules/frontend/newt/newt.c (min_window_height): Use the
	full description instead of the extended description when
	possible. This should make min_window_height() more independent
	from the get_full_description() internals.
	* src/modules/frontend/newt/newt.c (min_window_height): The height
	of the text needs to be added to the original size (decoration &
	buttons).
	* src/modules/frontend/newt/newt.c (need_separate_window):
	Document why we subtract 5 for the comparison of the window's
	height.
	* src/modules/frontend/newt/newt.c (need_separate_window): Do not
	use an extra window if the text fits exactly
	(min_window_height() == height-5)
diff -aruN ../orig/cdebconf-0.139/src/template.c ./cdebconf-0.139/src/template.c
--- ../orig/cdebconf-0.139/src/template.c	2008-12-26 14:46:33.000000000 +0100
+++ ./cdebconf-0.139/src/template.c	2009-02-26 10:31:41.214635082 +0100
@@ -619,17 +619,14 @@
 				in+=2;
 				asis=0;
 			}
+			else if (*(in+1) == 0)
+				*out = 0;
 			else if (*(in+1) == ' ')
 				asis=1;
 			else if (asis)
 				asis=0;
 			else
-			{
-				if (*(in+1) != 0)
-					*out = ' ';
-				else
-					*out = 0;
-			}
+				*out = ' ';
 		}
 		out++;
 	}
diff -aruN ../orig/cdebconf-0.139/src/modules/frontend/newt/newt.c ./cdebconf-0.139/src/modules/frontend/newt/newt.c
--- ../orig/cdebconf-0.139/src/modules/frontend/newt/newt.c	2009-02-13 17:43:37.000000000 +0100
+++ ./cdebconf-0.139/src/modules/frontend/newt/newt.c	2009-02-26 16:17:12.907008645 +0100
@@ -119,6 +119,9 @@
 
 static void newt_progress_stop(struct frontend *obj);
 
+/* Result must be freed by the caller */
+static char *get_full_description(struct frontend *obj, struct question *q);
+
 #include "cdebconf_newt.h"
 
 /*  Padding of title width, allows for leading "[!!] " before title
@@ -275,15 +278,22 @@
 static int
 min_window_height(struct frontend *obj, struct question *q, int win_width)
 {
+    // start with a blank or description (note and error)
+    // End with <Continue>/boolean buttons + blank
     int height = 3;
     char *type = q->template->type;
-    char *q_ext_text;
+    char *q_text;
 
-    q_ext_text = q_get_extended_description(obj, q);
-    if (q_ext_text != NULL)
-        height = cdebconf_newt_get_text_height(q_ext_text, win_width) + 1;
+    if (strcmp(q->template->type, "note") == 0 || strcmp(q->template->type, "error") == 0)
+        q_text = q_get_extended_description(obj, q);
+    else
+        q_text = get_full_description(obj, q);
+    if (q_text != NULL) {
+        height += cdebconf_newt_get_text_height(q_text, win_width) + 1;
+        free (q_text);
+    }
     if (strcmp(type, "multiselect") == 0 || strcmp(type, "select") == 0)
-        height += 4; // at least three lines for choices + blank line
+        height += 4; // x lines for choices + blank line
     else if (strcmp(type, "string") == 0 || strcmp(type, "password") == 0)
         height += 2; // input line + blank line
     // the others don't need more space
@@ -298,7 +308,8 @@
 
     newtGetScreenSize(&width, &height);
     x = min_window_height(obj, q, width-7);
-    return (x >= height-5);
+    return (x > height-5);
+    // 5: blue border + title + bottom frame + shadow + menu
 }
 
 static char *