[sysprof/wip/gtk4-port] libsysprof-ui: make the boxes fit in scrollmap better

[Christian Hergert <chergert src gnome org>]

commit 17d2c16957c28be55fbb95cbe2fa4050b893cc50
Author: Christian Hergert <chergert redhat com>
Date:   Fri Apr 1 16:48:18 2022 -0700

    libsysprof-ui: make the boxes fit in scrollmap better

 src/libsysprof-ui/sysprof-scrollmap.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
---
diff --git a/src/libsysprof-ui/sysprof-scrollmap.c b/src/libsysprof-ui/sysprof-scrollmap.c
index e21683bc..6dbddbb9 100644
--- a/src/libsysprof-ui/sysprof-scrollmap.c
+++ b/src/libsysprof-ui/sysprof-scrollmap.c
@@ -161,7 +161,7 @@ draw_boxes (const GtkAllocation *alloc,
             int                  n_boxes,
             const GdkRGBA       *color)
 {
-  int y = alloc->height - BOX_SIZE;
+  int y = alloc->y + alloc->height - BOX_SIZE;
 
   for (int i = 0; i < n_boxes; i++)
     {
@@ -187,6 +187,10 @@ sysprof_scrollmap_snapshot (GtkWidget   *widget,
     goto chainup;
 
   gtk_widget_get_allocation (widget, &alloc);
+
+  alloc.y += 3;
+  alloc.height -= 6;
+
   max_boxes = alloc.height / (BOX_SIZE + 1) - 1;
 
   style_context = gtk_widget_get_style_context (widget);
@@ -265,6 +269,7 @@ sysprof_scrollmap_class_init (SysprofScrollmapClass *klass)
   widget_class->snapshot = sysprof_scrollmap_snapshot;
 
   gtk_widget_class_set_layout_manager_type (widget_class, GTK_TYPE_BIN_LAYOUT);
+  gtk_widget_class_set_css_name (widget_class, "scrollmap");
 }
 
 static void