From 242fa1ee46f90f451c625e90f16927e13030c0a0 Mon Sep 17 00:00:00 2001
From: Simon Howard
Date: Tue, 29 Apr 2014 01:47:13 -0400
Subject: textscreen: Fix jump when clicking on scrollbars.

Clicking on a scrollbar should scroll the cursor to that location, but
the logic for it was buggy because of loss of precision when doing an
integer divide. When dividing by bar_max, seek up to the nearest value
so that the cursor always arrives where we clicked.

Thanks to Alexandre-Xavier for reporting this bug. This fixes #359.
---
 textscreen/txt_scrollpane.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/textscreen/txt_scrollpane.c b/textscreen/txt_scrollpane.c
index c53f68df..3fd32124 100644
--- a/textscreen/txt_scrollpane.c
+++ b/textscreen/txt_scrollpane.c
@@ -487,7 +487,7 @@ static void TXT_ScrollPaneMousePress(TXT_UNCAST_ARG(scrollpane),
             int range = FullWidth(scrollpane) - scrollpane->w;
             int bar_max = scrollpane->w - 3;
 
-            scrollpane->x = ((rel_x - 1) * range + (bar_max / 2)) / bar_max;
+            scrollpane->x = ((rel_x - 1) * range + bar_max - 1) / bar_max;
         }
 
         return;
@@ -509,7 +509,7 @@ static void TXT_ScrollPaneMousePress(TXT_UNCAST_ARG(scrollpane),
             int range = FullHeight(scrollpane) - scrollpane->h;
             int bar_max = scrollpane->h - 3;
 
-            scrollpane->y = ((rel_y - 1) * range + (bar_max / 2)) / bar_max;
+            scrollpane->y = ((rel_y - 1) * range + bar_max - 1) / bar_max;
         }
 
         return;
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