Added keyboard press detection

main.cpp

     if ( err ) {
         return err;
     }
+    err = xengine->grabKeyboard();
+    if ( err ) {
+        return err;
+    }
     while ( running ) {
         // "ticking" the xengine makes it process all queued events.
         xengine->tick();
+        // If the user presses any key on the keyboard, exit the application.
+        if ( xengine->m_keypressed ) {
+            printf( "X=0\n" );
+            printf( "Y=0\n" );
+            printf( "W=0\n" );
+            printf( "H=0\n" );
+            fprintf( stderr, "User pressed key. Canceled selection.\n" );
+            state = -1;
+            running = false;
+        }
         if ( xengine->mouseDown( 3 ) ) {
             printf( "X=0\n" );
             printf( "Y=0\n" );
         // bad computer.
         usleep( 1000 );
     }
+    xengine->releaseCursor();
+    xengine->releaseKeyboard();
     // Clean up global classes.
     delete xengine;
     delete options;

x.cpp

 slrn::XEngine* xengine = new slrn::XEngine();
 
 slrn::XEngine::XEngine() {
+    m_keypressed = false;
     m_display = NULL;
     m_visual = NULL;
     m_screen = NULL;
     return 0;
 }
 
+int slrn::XEngine::grabKeyboard() {
+    if ( !m_good ) {
+        return 1;
+    }
+    int err = XGrabKeyboard( m_display, m_root, False,
+                             GrabModeAsync, GrabModeAsync, CurrentTime );
+    if ( err != GrabSuccess ) {
+        fprintf( stderr, "Error: Failed to grab X keyboard.\n" );
+        fprintf( stderr, "This can be caused by launching slrn incorrectly.\n" );
+        fprintf( stderr, "gnome-session launches it fine from keyboard binds.\n" );
+        return 1;
+    }
+}
+
+int slrn::XEngine::releaseKeyboard() {
+    if ( !m_good ) {
+        return 1;
+    }
+    XUngrabKeyboard( m_display, CurrentTime );
+    return 0;
+}
+
 int slrn::XEngine::grabCursor( slrn::CursorType type ) {
     if ( !m_good ) {
         return 1;
                             GrabModeAsync, GrabModeAsync, m_root, xfontcursor, CurrentTime );
     if ( err != GrabSuccess ) {
         fprintf( stderr, "Error: Failed to grab X cursor.\n" );
+        fprintf( stderr, "This can be caused by launching slrn incorrectly.\n" );
+        fprintf( stderr, "gnome-session launches it fine from keyboard binds.\n" );
         return 1;
     }
 
                 }
                 break;
             }
+            // For this particular utility, we only care if a key is pressed.
+            // I'm too lazy to implement a keyhandler for that.
+            case KeyPress: {
+                m_keypressed = true;
+                break;
+            }
+            case KeyRelease: {
+                //m_keypressed = false;
+                break;
+            }
             default: break;
         }
     }

x.hpp

     int                 init( std::string display );
     void                tick();
     int                 grabCursor( slrn::CursorType type );
+    int                 grabKeyboard();
     int                 releaseCursor();
+    int                 releaseKeyboard();
     void                setCursor( slrn::CursorType type );
     void                drawRect( int x, int y, unsigned int w, unsigned int h );
     void                addRect( Rectangle* rect );
     bool                mouseDown( unsigned int button );
     WindowRectangle     m_hoverWindow;
     Window              m_hoverXWindow;
+    bool                m_keypressed;
 private:
     void                updateHoverWindow();
     void                updateHoverWindow( Window child );