comparison layer/Colour3DPlotLayer.cpp @ 470:26d1ddc0ce96

* another, rather trivial, optimisation

     float srRatio = float(mmsr) / float(msr);
 
     int x0 = rect.left();
     int x1 = rect.right() + 1;
 
-    int w = x1 - x0;
+    const int w = x1 - x0; // const so it can be used as array size below
     int h = v->height();
     int sh = m_model->getHeight();
 
     int symin = m_miny;
     int symax = m_maxy;

 //        std::cerr << "not using peaks cache" << std::endl;
     }
 
     int psy1i = -1;
     int sw = source->width();
+    
+    long xf = -1;
+    long nxf = v->getFrameForX(x0);
+
+    int sxa[w * 2];
+    for (int x = 0; x < w; ++x) {
+
+        xf = nxf;
+        nxf = xf + zoomLevel;
+
+        float sx0 = (float(xf) / srRatio - modelStart) / modelResolution;
+        float sx1 = (float(nxf) / srRatio - modelStart) / modelResolution;
+
+        int sx0i = int(sx0 + 0.001);
+        int sx1i = int(sx1);
+
+        sxa[x*2] = sx0i;
+        sxa[x*2 + 1] = sx1i;
+    }
 
     for (int y = 0; y < h; ++y) {
 
         float sy0 = symin + (float(h - y - 1) * (symax - symin)) / h;
         float sy1 = symin + (float(h - y) * (symax - symin)) / h;

 
             if (sy < 0 || sy >= source->height()) continue;
 
             uchar *sourceLine = source->scanLine(sy);
             
-            long xf = -1;
-            long nxf = v->getFrameForX(x0);
-
-            int nsxi = -1;
-
             for (int x = 0; x < w; ++x) {
 
-                xf = nxf;
-                nxf = xf + zoomLevel;
-
-                if (xf < 0) {
-                    peaks[x] = 0;
-                    continue;
-                }
-
-                float sx0 = (float(xf) / srRatio - modelStart) / modelResolution;
-                float sx1 = (float(nxf) / srRatio - modelStart) / modelResolution;
-            
-                int sx0i = int(sx0 + 0.001);
-                int sx1i = int(sx1);
+                int sx0i = sxa[x*2];
+                int sx1i = sxa[x*2 + 1];
 
                 uchar peak = 0;
                 for (int sx = sx0i; sx <= sx1i; ++sx) {
                     if (sx < 0 || sx >= sw) continue;
                     if (sourceLine[sx] > peak) peak = sourceLine[sx];