[gimp] plug-ins: use an epsilon to compare double values.

[Jehan Pagès <jehanp src gnome org>]

commit 0cdca57d126f2714d761e3e3dcd663722e6fda47
Author: Jehan <jehan girinstud io>
Date:   Tue Dec 20 04:07:45 2016 +0100

    plug-ins: use an epsilon to compare double values.
    
    Also take into account the case when the minimum possible print
    resolution is higher than the expected image resolution. We don't want
    to remember the print resolution if it is this lower value either.
    See commit 7335dc8.

 plug-ins/print/print-page-layout.c |    2 ++
 plug-ins/print/print-settings.c    |    9 ++++++++-
 plug-ins/print/print.h             |    2 ++
 3 files changed, 12 insertions(+), 1 deletions(-)
---
diff --git a/plug-ins/print/print-page-layout.c b/plug-ins/print/print-page-layout.c
index 48f0a64..3af04bc 100644
--- a/plug-ins/print/print-page-layout.c
+++ b/plug-ins/print/print-page-layout.c
@@ -918,6 +918,8 @@ print_size_info_set_page_setup (PrintSizeInfo *info)
       x = y = max;
     }
 
+  data->min_xres = x;
+  data->min_yres = y;
   gimp_size_entry_set_refval_boundaries (info->resolution_entry, 0,
                                          x, GIMP_MAX_RESOLUTION);
   gimp_size_entry_set_refval_boundaries (info->resolution_entry, 1,
diff --git a/plug-ins/print/print-settings.c b/plug-ins/print/print-settings.c
index 5fe9c00..9bb9c33 100644
--- a/plug-ins/print/print-settings.c
+++ b/plug-ins/print/print-settings.c
@@ -88,7 +88,14 @@ print_settings_save (PrintData *data)
 
       g_key_file_set_integer (key_file, "image-setup",
                               "unit", data->unit);
-      if (xres != data->xres || yres != data->yres)
+      /* Do not save the print resolution when it is the expected image
+       * resolution so that changing it (i.e. in "print size" dialog)
+       * is not overrided by any previous prints.
+       */
+      if ((data->min_xres <= xres && ABS (xres - data->xres) > 0.1)          ||
+          (data->min_yres <= yres && ABS (yres - data->yres) > 0.1)          ||
+          (data->min_xres > xres && ABS (data->min_xres - data->xres) > 0.1) ||
+          (data->min_yres > yres && ABS (data->min_yres - data->yres) > 0.1))
         {
           g_key_file_set_double  (key_file, "image-setup",
                                   "x-resolution", data->xres);
diff --git a/plug-ins/print/print.h b/plug-ins/print/print.h
index 3236a5b..f665f94 100644
--- a/plug-ins/print/print.h
+++ b/plug-ins/print/print.h
@@ -44,6 +44,8 @@ typedef struct
   GimpUnit            unit;
   gdouble             xres;
   gdouble             yres;
+  gdouble             min_xres;
+  gdouble             min_yres;
   GimpUnit            image_unit;
   gdouble             offset_x;
   gdouble             offset_y;