Pipette and "On Preview Widgets" branch. See issue 227

The pipette part is already working quite nice but need to be finished. The widgets part needs more work...

rtengine/klt/convolve.h

@@ -0,0 +1,32 @@
+/*********************************************************************
+ * convolve.h
+ *********************************************************************/
+
+#ifndef _CONVOLVE_H_
+#define _CONVOLVE_H_
+
+#include "klt.h"
+#include "klt_util.h"
+
+void _KLTToFloatImage(
+  KLT_PixelType *img,
+  int ncols, int nrows,
+  _KLT_FloatImage floatimg);
+
+void _KLTComputeGradients(
+  _KLT_FloatImage img,
+  float sigma,
+  _KLT_FloatImage gradx,
+  _KLT_FloatImage grady);
+
+void _KLTGetKernelWidths(
+  float sigma,
+  int *gauss_width,
+  int *gaussderiv_width);
+
+void _KLTComputeSmoothedImage(
+  _KLT_FloatImage img,
+  float sigma,
+  _KLT_FloatImage smooth);
+
+#endif