allow negative data log plots with OpenGL+FLTK graphics (bug #34232) * mx-inlines.cc (mx_inline_any_positive): New function. * lo-mappers.h (xpositive_sign (double), xpositive_sign (float)): New functions. * fNDArray.h, fNDArray.cc (FloatNDArray::any_element_is_positive): New function. * fMatrix.h, fMatrix.cc (FloatMatrix::any_element_is_positive): New function. * dNDArray.h, dNDArray.cc (NDArray::any_element_is_positive): New function. * dMatrix.h, dMatrix.cc (Matrix::any_element_is_positive): New function. * graphics.h.in (log_scaler::do_neg_scale): New function. (log_scaler::scale (const Matrix&) const, log_scaler::scale (const NDArray&) const): Call do_neg_scale if no array elements are positive. * graphics.cc (axes::properties::get_axis_limits): Omit zero from positive values for log plots. Correctly widen range for all negative log plots.

--- a/src/graphics.cc	Wed Oct 26 07:44:55 2011 -0400
+++ b/src/graphics.cc	Wed Oct 26 14:19:54 2011 -0400
@@ -5568,7 +5568,7 @@
               retval(1) = pow (10., retval(1));
               return retval;
             }
-          if ((min_val <= 0 && max_val >= 0))
+          if ((min_val <= 0 && max_val > 0))
             {
               warning ("axis: omitting nonpositive data in log plot");
               min_val = min_pos;
@@ -5588,8 +5588,8 @@
           else
             {
               // Log plots with all negative data
-              min_val = -pow (10, gnulib::floor (log10 (-min_val)));
-              max_val = -pow (10, std::ceil (log10 (-max_val)));
+              min_val = -pow (10, std::ceil (log10 (-min_val)));
+              max_val = -pow (10, gnulib::floor (log10 (-max_val)));
             }
         }
       else