Add dynamic adjustment of waterfall level (contributed code)

[GoogleCodeExporter]

Code contributed from - Gary / k3wow 

Index: Source/Console/display.cs
===================================================================
--- Source/Console/display.cs   (revision 252)
+++ Source/Console/display.cs   (working copy)
@@ -772,6 +772,7 @@
                        get { return waterfall_low_threshold; }
                        set { waterfall_low_threshold = value; }
                }
+        private static float waterfall_dynamic_low_threshold =
-130.0f;

                private static float display_line_width = 1.0F;
                public static float DisplayLineWidth
@@ -3067,6 +3068,11 @@
                                row = (byte *)bitmapData.Scan0;

                                // draw new data
+                float min_waterfall_value = float.MaxValue;
+                float actual_waterfall_dynamic_low_threshold =
waterfall_low_threshold;
+                if (waterfall_low_threshold == 0)
+                    actual_waterfall_dynamic_low_threshold =
waterfall_dynamic_low_threshold;
+
                                for(int i=0; i<W; i++)       // for each pixel in the new line
                                {
                                        int R, G, B;            // variables to save Red, Green and Blue component
values
@@ -3105,8 +3111,10 @@
                                        }*/

                                        //waterfall_data[i] = (float)i/W*(waterfall_high_threshold -
waterfall_low_threshold) + waterfall_low_threshold;
+                    if (waterfall_data[i] < min_waterfall_value)
+                        min_waterfall_value = waterfall_data[i];

-                                       if(waterfall_data[i] <= 
waterfall_low_threshold)
+                    if (waterfall_data[i] <=
actual_waterfall_dynamic_low_threshold)
                                        {
                                                R = waterfall_low_color.R;
                                                G = waterfall_low_color.G;
@@ -3120,8 +3128,8 @@
                                        }
                                        else // value is between low and high
                                        {
-                                               float range = 
waterfall_high_threshold -
waterfall_low_threshold;
-                                               float offset = 
waterfall_data[i] - waterfall_low_threshold;
+                        float range = waterfall_high_threshold -
actual_waterfall_dynamic_low_threshold;
+                        float offset = waterfall_data[i] -
actual_waterfall_dynamic_low_threshold;
                                                float overall_percent = offset / range; // value from 0.0 to
1.0 where 1.0 is high and 0.0 is low.

                                                if(overall_percent < (float)2/9) // background to blue
@@ -3180,6 +3188,13 @@
                                        row[i*pixel_size + 1] = (byte)G;
                                        row[i*pixel_size + 2] = (byte)R;
                                }
+
+                // tweak a dynamic low threshold to better meet band
conditions
+                if (min_waterfall_value <
waterfall_dynamic_low_threshold)
+                    waterfall_dynamic_low_threshold -= 0.1f;
+                else
+                    waterfall_dynamic_low_threshold += 0.1f;
+
                                if(rx == 1)
                                        waterfall_bmp.UnlockBits(bitmapData);
                                else 

Original issue reported on code.google.com by mccleme...@gmail.com on 21 Jul 2010 at 1:44