Spectrum/Waterfall display zoom feature - work in progress (issue #33)

Implements zoom in/out by mouse scroll wheel and by right-click context
menu.

Still have to add ability to drag spectrum left/right when zoomed in.

src/spectrum/DFTSize.java

@@ -0,0 +1,46 @@
+/*******************************************************************************
+ *     SDR Trunk 
+ *     Copyright (C) 2014 Dennis Sheirer
+ * 
+ *     This program is free software: you can redistribute it and/or modify
+ *     it under the terms of the GNU General Public License as published by
+ *     the Free Software Foundation, either version 3 of the License, or
+ *     (at your option) any later version.
+ * 
+ *     This program is distributed in the hope that it will be useful,
+ *     but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *     GNU General Public License for more details.
+ * 
+ *     You should have received a copy of the GNU General Public License
+ *     along with this program.  If not, see <http://www.gnu.org/licenses/>
+ ******************************************************************************/
+package spectrum;
+
+public enum DFTSize
+{
+	FFT00512( 512 ),
+	FFT01024( 1024 ),
+	FFT02048( 2048 ),
+	FFT04096( 4096 ),
+	FFT08192( 8192 ),
+	FFT16384( 16384 ),
+	FFT32768( 32768 );
+	
+	private int mWidth;
+	
+	private DFTSize( int width )
+	{
+		mWidth = width;
+	}
+	
+	public int getSize()
+	{
+		return mWidth;
+	}
+	
+	public String getLabel()
+	{
+		return String.valueOf( mWidth );
+	}
+}