[hitori] interface: Fix -Wdouble-promotion warnings

[Philip Withnall <pwithnall src gnome org>]

commit e969d491f06e9c180a251beb5808dcfbcc7ea2f9
Author: Philip Withnall <withnall endlessm com>
Date:   Mon Oct 16 14:35:15 2017 +0100

    interface: Fix -Wdouble-promotion warnings
    
    There was no good reason for these variables to be floats rather than
    doubles.
    
    Signed-off-by: Philip Withnall <withnall endlessm com>

 src/interface.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/interface.c b/src/interface.c
index d322683..e402bb7 100644
--- a/src/interface.c
+++ b/src/interface.c
@@ -134,7 +134,7 @@ lookup_color (GtkStyleContext *style_context, const gchar *name, GdkRGBA *result
 }
 
 static void
-draw_cell (Hitori *hitori, GtkStyleContext *style_context, cairo_t *cr, gfloat cell_size, gdouble x_pos, 
gdouble y_pos,
+draw_cell (Hitori *hitori, GtkStyleContext *style_context, cairo_t *cr, gdouble cell_size, gdouble x_pos, 
gdouble y_pos,
            HitoriVector iter)
 {
        gchar *text;
@@ -307,7 +307,7 @@ hitori_draw_cb (GtkWidget *drawing_area, cairo_t *cr, Hitori *hitori)
 
        /* Draw a hint if applicable */
        if (hitori->hint_status % 2 == 1) {
-               gfloat line_width = BORDER_LEFT * 2.5;
+               gdouble line_width = BORDER_LEFT * 2.5;
                GdkRGBA colour;
                lookup_color (style_context, "hint-border-color", &colour);
                gdk_cairo_set_source_rgba (cr, &colour);