Fix bug: integer underflow in startup phase

When fluxbox comes up some of it's drawables span a 1x1 area. Subtracting from
such small numbers bigger ones always lead to massive problems when 'unsigned
int' are involved:

'button_width' is an unsigned int of '1' (this might be caused by another
issue or on purpose, anyway), subtracting -10 or any other number should
result in something < 0 when in reality an integer underflow happen: max_width
is now MAX_INT-something big. This makes fluxbox crash under certain
circumstances.

This fixes bug #1116.

1 files changed, 7 insertions, 1 deletions

diff --git a/src/FbTk/TextButton.cc b/src/FbTk/TextButton.cc
index 611580c..a177f25 100644
--- a/src/FbTk/TextButton.cc
+++ b/src/FbTk/TextButton.cc
@@ -143,11 +143,17 @@ void TextButton::drawText(int x_offset, int y_offset, FbDrawable *drawable) {
     unsigned int textlen = visual.size();
     unsigned int button_width = width();
     unsigned int button_height = height();
+    const int max_width = static_cast<int>(button_width) - x_offset -
+        m_left_padding - m_right_padding;
+
+    if (max_width <= bevel()) {
+        return;
+    }
 
     translateSize(m_orientation, button_width, button_height);
 
     // horizontal alignment, cut off text if needed
-    int align_x = FbTk::doAlignment(button_width - x_offset - m_left_padding - m_right_padding,
+    int align_x = FbTk::doAlignment(max_width,
                                     bevel(), justify(), font(),
                                     visual.data(), visual.size(),
                                     textlen); // return new text len