[sysprof/wip/chergert/sysprof-3] libsysprof-ui: add some helpers to zoom manager

[Christian Hergert <chergert src gnome org>]

commit ff7d5cb9d3fa566a681b6a2ca843a264d181adf6
Author: Christian Hergert <chergert redhat com>
Date:   Tue May 14 13:07:09 2019 -0700

    libsysprof-ui: add some helpers to zoom manager
    
    This should be able to help us cleanup some duplicated code in various
    places so that we keep our timings associated amongst different visualizing
    widgets.

 src/libsysprof-ui/sysprof-zoom-manager.c | 39 ++++++++++++++++++++------------
 src/libsysprof-ui/sysprof-zoom-manager.h |  6 +++++
 2 files changed, 30 insertions(+), 15 deletions(-)
---
diff --git a/src/libsysprof-ui/sysprof-zoom-manager.c b/src/libsysprof-ui/sysprof-zoom-manager.c
index ed7b045..cdb0665 100644
--- a/src/libsysprof-ui/sysprof-zoom-manager.c
+++ b/src/libsysprof-ui/sysprof-zoom-manager.c
@@ -27,6 +27,9 @@
 
 #include "sysprof-zoom-manager.h"
 
+#define DEFAULT_PIXELS_PER_SEC (20.0)
+#define NSEC_PER_SEC G_GINT64_CONSTANT(1000000000)
+
 struct _SysprofZoomManager
 {
   GObject parent_instance;
@@ -56,21 +59,9 @@ G_DEFINE_TYPE_EXTENDED (SysprofZoomManager, sysprof_zoom_manager, G_TYPE_OBJECT,
 
 static GParamSpec *properties [N_PROPS];
 static gdouble zoom_levels[] = {
-  0.3,
-  0.5,
-  0.67,
-  0.80,
-  0.90,
-  1.0,
-  1.5,
-  2.0,
-  2.5,
-  3.0,
-  5.0,
-  10.0,
-  20.0,
-  30.0,
-  50.0,
+  0.3, 0.5, 0.67, 0.80, 0.90,
+  1.0, 1.5, 2.0, 2.5, 3.0,
+  5.0, 10.0, 20.0, 30.0, 50.0,
 };
 
 static void
@@ -506,3 +497,21 @@ sysprof_zoom_manager_get_zoom_label (SysprofZoomManager *self)
   else
     return g_strdup_printf ("%d%%", (gint)percent);
 }
+
+gint64
+sysprof_zoom_manager_get_duration_for_width (SysprofZoomManager *self,
+                                             gint                width)
+{
+  g_return_val_if_fail (SYSPROF_IS_ZOOM_MANAGER (self), 0);
+
+  return NSEC_PER_SEC * ((gdouble)width / (DEFAULT_PIXELS_PER_SEC * self->zoom));
+}
+
+gint
+sysprof_zoom_manager_get_width_for_duration (SysprofZoomManager *self,
+                                             gint64              duration)
+{
+  g_return_val_if_fail (SYSPROF_IS_ZOOM_MANAGER (self), 0);
+
+  return (gdouble)duration / (gdouble)NSEC_PER_SEC * DEFAULT_PIXELS_PER_SEC * self->zoom;
+}
diff --git a/src/libsysprof-ui/sysprof-zoom-manager.h b/src/libsysprof-ui/sysprof-zoom-manager.h
index 62aa45e..4c7859b 100644
--- a/src/libsysprof-ui/sysprof-zoom-manager.h
+++ b/src/libsysprof-ui/sysprof-zoom-manager.h
@@ -64,5 +64,11 @@ void                sysprof_zoom_manager_set_zoom         (SysprofZoomManager *s
                                                            gdouble             zoom);
 SYSPROF_AVAILABLE_IN_ALL
 gchar              *sysprof_zoom_manager_get_zoom_label   (SysprofZoomManager *self);
+SYSPROF_AVAILABLE_IN_ALL
+gint                sysprof_zoom_manager_get_width_for_duration (SysprofZoomManager *self,
+                                                                 gint64              duration);
+SYSPROF_AVAILABLE_IN_ALL
+gint64              sysprof_zoom_manager_get_duration_for_width (SysprofZoomManager *self,
+                                                                 gint                width);
 
 G_END_DECLS