diff layer/ScrollableMagRangeCache.h @ 1119:be5b91ec81a0 spectrogram-minor-refactor

Inch toward using the mag cache (currently will crash with debug exception)

--- a/layer/ScrollableMagRangeCache.h	Wed Jul 20 08:30:20 2016 +0100
+++ b/layer/ScrollableMagRangeCache.h	Wed Jul 20 08:42:04 2016 +0100
@@ -95,12 +95,33 @@
     bool isColumnSet(int column) const {
 	return in_range_for(m_ranges, column) && m_ranges.at(column).isSet();
     }
+
+    bool areColumnsSet(int x, int count) const {
+	for (int i = 0; i < count; ++i) {
+	    if (!isColumnSet(x + i)) return false;
+	}
+	return true;
+    }
     
-    const MagnitudeRange &getRange(int column) const {
+    /**
+     * Get the magnitude range for a single column.
+     */
+    MagnitudeRange getRange(int column) const {
 	return m_ranges.at(column);
     }
 
     /**
+     * Get the magnitude range for a range of columns.
+     */
+    MagnitudeRange getRange(int x, int count) const {
+	MagnitudeRange r;
+	for (int i = 0; i < count; ++i) {
+	    r.sample(m_ranges.at(x + i));
+	}
+	return r;
+    }
+    
+    /**
      * Set the new start frame for the cache, according to the
      * geometry of the supplied LayerGeometryProvider, if possible
      * also moving along any existing valid data within the cache so