From 4bea46c1ce07333d06360137991a4ea1aa114f56 Mon Sep 17 00:00:00 2001
From: Albrecht Schlosser <albrechts.fltk@online.de>
Date: Mon, 23 May 2011 19:16:16 +0000
Subject: src/screen_xywh.cxx: Fix STR #2637, part 1. Fix array bounds error
 when Xinerama and Xlib disagree about number of screens. Fix setting vertical
 resolution (dpi) of different monitors.

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@8727 ea41ed52-d2ee-0310-a9c1-e6b18d33e121
---
 src/screen_xywh.cxx | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

(limited to 'src')

diff --git a/src/screen_xywh.cxx b/src/screen_xywh.cxx
index 7b373819a..410e4eb9e 100644
--- a/src/screen_xywh.cxx
+++ b/src/screen_xywh.cxx
@@ -155,11 +155,15 @@ static void screen_init() {
   if (XineramaIsActive(fl_display)) {
     screens = XineramaQueryScreens(fl_display, &num_screens);
     int i;
+    // Xlib and Xinerama may disagree on the screen count. Sigh...
+    // Use the minimum of the reported counts.
+    // Use the previous screen's info for non-existent ones.
+    int sc = ScreenCount(fl_display); // Xlib screen count
     for (i=0; i<num_screens; i++) {
-      int mm = DisplayWidthMM(fl_display, i);
-      dpi[i][0] = mm ? screens[i].width*25.4f/mm : 0.0f;
-      mm = DisplayHeightMM(fl_display, fl_screen);
-      dpi[i][1] = mm ? screens[i].height*25.4f/mm : dpi[i][0];
+      int mm = (i < sc) ? DisplayWidthMM(fl_display, i) : 0;
+      dpi[i][0] = mm ? screens[i].width*25.4f/mm : (i > 0) ? dpi[i-1][0] : 0.0f;
+      mm = (i < sc) ? DisplayHeightMM(fl_display, i) : 0;
+      dpi[i][1] = mm ? screens[i].height*25.4f/mm : (i > 0) ? dpi[i-1][1] : 0.0f;
     }
   } else { // ! XineramaIsActive()
     num_screens = 1;
-- 
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