# HG changeset patch
# User John W. Eaton <jwe@octave.org>
# Date 1328202261 18000
# Node ID 17de694961f5f3ac4c73ae5fe48824baad7ae5d9
# Parent  7a7ce92cff5626b56e9d85aa0b0d235e2dee4c03
make panning work for logscale axes

* graphics.cc (do_translate): New static function.:
* graphics.cc, graphics.h.in (axes::properties): Use it.
Args are now beginning and ending coordinates, not deltas.
* __init_fltk__.cc (plot_window::handle): Pass beginning and ending
* coordinates to translate_view, not deltas.

diff -r 7a7ce92cff56 -r 17de694961f5 src/DLD-FUNCTIONS/__init_fltk__.cc
--- a/src/DLD-FUNCTIONS/__init_fltk__.cc	Thu Feb 02 11:59:50 2012 -0500
+++ b/src/DLD-FUNCTIONS/__init_fltk__.cc	Thu Feb 02 12:04:21 2012 -0500
@@ -1301,7 +1301,7 @@
                     pixel2pos (ax_obj, Fl::event_x (), Fl::event_y (), x1, y1);
 
                     if (gui_mode == pan_zoom)
-                      ap.translate_view (x0 - x1, y0 - y1);
+                      ap.translate_view (x0, x1, y0, y1);
                     else if (gui_mode == rotate_zoom)
                       {
                         double daz, del;
diff -r 7a7ce92cff56 -r 17de694961f5 src/graphics.cc
--- a/src/graphics.cc	Thu Feb 02 11:59:50 2012 -0500
+++ b/src/graphics.cc	Thu Feb 02 12:04:21 2012 -0500
@@ -6659,8 +6659,68 @@
   update_ylim (false);
 }
 
-void
-axes::properties::translate_view (double delta_x, double delta_y)
+static Matrix
+do_translate (double x0, double x1, const Matrix& lims, bool is_logscale)
+{
+  Matrix new_lims = lims;
+
+  double lo = lims(0);
+  double hi = lims(1);
+
+  bool is_negative = lo < 0 && hi < 0;
+
+  double delta;
+
+  if (is_logscale)
+    {
+      if (is_negative)
+        {
+          double tmp = hi;
+          hi = std::log10 (-lo);
+          lo = std::log10 (-tmp);
+          x0 = -x0;
+          x1 = -x1;
+        }
+      else
+        {
+          hi = std::log10 (hi);
+          lo = std::log10 (lo);
+        }
+
+      delta = std::log10 (x0) - std::log10 (x1);
+    }
+  else
+    {
+      delta = x0 - x1;
+    }
+
+  // Perform the translation
+  lo += delta;
+  hi += delta;
+
+  if (is_logscale)
+    {
+      if (is_negative)
+        {
+          double tmp = -std::pow (10.0, hi);
+          hi = -std::pow (10.0, lo);
+          lo = tmp;
+        }
+      else
+        {
+          lo = std::pow (10.0, lo);
+          hi = std::pow (10.0, hi);
+        }
+    }
+
+  new_lims(0) = lo;
+  new_lims(1) = hi;
+
+  return new_lims;
+}
+
+void
+axes::properties::translate_view (double x0, double x1, double y0, double y1)
 {
   // FIXME: Do we need error checking here?
   Matrix xlims = get_xlim ().matrix_value ();
@@ -6680,17 +6740,8 @@
   double max_neg_y = -octave_Inf;
   get_children_limits (miny, maxy, min_pos_y, max_neg_y, kids, 'y');
 
-  if (! xscale_is ("log"))
-    {
-      xlims (0) += delta_x;
-      xlims (1) += delta_x;
-    }
-
-  if (! yscale_is ("log"))
-    {
-      ylims (0) += delta_y;
-      ylims (1) += delta_y;
-    }
+  xlims = do_translate (x0, x1, xlims, xscale_is ("log"));
+  ylims = do_translate (y0, y1, ylims, yscale_is ("log"));
 
   zoom (xlims, ylims, false);
 }
diff -r 7a7ce92cff56 -r 17de694961f5 src/graphics.h.in
--- a/src/graphics.h.in	Thu Feb 02 11:59:50 2012 -0500
+++ b/src/graphics.h.in	Thu Feb 02 12:04:21 2012 -0500
@@ -3663,7 +3663,7 @@
     void zoom_about_point (double x, double y, double factor,
                            bool push_to_zoom_stack = true);
     void zoom (const Matrix& xl, const Matrix& yl, bool push_to_zoom_stack = true);
-    void translate_view (double delta_x, double delta_y);
+    void translate_view (double x0, double x1, double y0, double y1);
     void rotate_view (double delta_az, double delta_el);
     void unzoom (void);
     void clear_zoom_stack (void);