[ghex] gtkhex: dynamically sized offset column

[Logan Rathbone <larathbone src gnome org>]

commit 4d0792d13b6a239d9e957b6b4d14915f5694c165
Author: Logan Rathbone <poprocks gmail com>
Date:   Mon Dec 20 20:32:22 2021 -0500

    gtkhex: dynamically sized offset column

 src/gtkhex-layout-manager.c | 42 ++++++++++++++++--------------------------
 src/gtkhex-layout-manager.h |  3 +++
 src/gtkhex.c                | 22 ++++++++++++++++++----
 3 files changed, 37 insertions(+), 30 deletions(-)
---
diff --git a/src/gtkhex-layout-manager.c b/src/gtkhex-layout-manager.c
index d0adf91..e853d3b 100644
--- a/src/gtkhex-layout-manager.c
+++ b/src/gtkhex-layout-manager.c
@@ -24,10 +24,7 @@
 
 #include "gtkhex-layout-manager.h"
 
-/* The CPL of the offsets column is constant; easier to just punch it in here
- * than to use config.h. Don't change unless you change code in gtkhex.c as well.
- */
-#define OFFSETS_CPL            8
+#define DEFAULT_OFFSET_CPL     8
 
 struct _GtkHexLayout {
        GtkLayoutManager parent_instance;
@@ -37,6 +34,7 @@ struct _GtkHexLayout {
 
        int cpl;
        int hex_cpl;
+       int offset_cpl;
 
        int cursor_x, cursor_y;
 };
@@ -259,28 +257,7 @@ gtk_hex_layout_allocate (GtkLayoutManager *layout_manager,
                                break;
                        case SCROLLBAR_COLUMN:  scrollbar = child;
                                break;
-
                        case NO_COLUMN:
-                       {
-#if 0
-                               GtkRequisition child_req;
-                               GtkAllocation alloc = {0};
-
-                               gtk_widget_get_preferred_size (child, &child_req, NULL);
-
-                               alloc.height = child_req.height;
-                               alloc.width = child_req.width;
-
-                               if (GTK_IS_POPOVER (child))
-                               {
-                                       alloc.x = self->cursor_x;
-                                       alloc.y = self->cursor_y;
-                               }
-
-                               gtk_widget_size_allocate (child, &alloc, -1);
-                               return;
-#endif
-                       }
                                break;
 
                                /* We won't test for this each loop. */
@@ -306,7 +283,7 @@ gtk_hex_layout_allocate (GtkLayoutManager *layout_manager,
                /* nb: offsets always goes at x coordinate 0 so just leave it as it's
                 * zeroed out anyway. */
 
-               off_alloc.width = OFFSETS_CPL * self->char_width +
+               off_alloc.width = self->offset_cpl * self->char_width +
                        margins.left + margins.right +
                        padding.left + padding.right +
                        borders.left + borders.right;
@@ -467,6 +444,7 @@ gtk_hex_layout_class_init (GtkHexLayoutClass *klass)
 static void
 gtk_hex_layout_init (GtkHexLayout *self)
 {
+       self->offset_cpl = DEFAULT_OFFSET_CPL;
        /* FIXME - dumb test initial default */
        self->char_width = 20;
        self->group_type = GTK_HEX_GROUP_BYTE;
@@ -516,6 +494,18 @@ gtk_hex_layout_set_cursor_pos (GtkHexLayout *layout, int x, int y)
        layout->cursor_y = y;
 }
 
+void
+gtk_hex_layout_set_offset_cpl (GtkHexLayout *layout, int offset_cpl)
+{
+       layout->offset_cpl = offset_cpl;
+}
+
+int
+gtk_hex_layout_get_offset_cpl (GtkHexLayout *layout)
+{
+       return layout->offset_cpl;
+}
+
 /* GtkHexLayoutChild - Public Methods */
 
 void
diff --git a/src/gtkhex-layout-manager.h b/src/gtkhex-layout-manager.h
index 023955d..df8360c 100644
--- a/src/gtkhex-layout-manager.h
+++ b/src/gtkhex-layout-manager.h
@@ -61,6 +61,9 @@ void                          gtk_hex_layout_set_group_type (GtkHexLayout *layout,
                                                GtkHexGroupType group_type);
 void                           gtk_hex_layout_set_cursor_pos (GtkHexLayout *layout,
                                                int x, int y);
+void                           gtk_hex_layout_set_offset_cpl (GtkHexLayout *layout,
+                                               int offset_cpl);
+int                                    gtk_hex_layout_get_offset_cpl (GtkHexLayout *layout);
 
 G_END_DECLS
 
diff --git a/src/gtkhex.c b/src/gtkhex.c
index d3e6f61..3b200ce 100644
--- a/src/gtkhex.c
+++ b/src/gtkhex.c
@@ -1058,6 +1058,8 @@ no_more_lines_to_draw:
 }
 #undef DO_RENDER_CURSOR
 
+#define BUFLEN 32
+#define MIN_CPL        8
 static void
 render_offsets (GtkHex *gh,
                 cairo_t *cr,
@@ -1068,8 +1070,10 @@ render_offsets (GtkHex *gh,
        GdkRGBA fg_color;
        GtkAllocation allocation;
        GtkStyleContext *context;
-       /* offset chars (8) + 1 (null terminator) */
-       char offstr[9];
+       char buf[BUFLEN] = {0};
+       char fmt[BUFLEN] = {0};
+       char off_str[BUFLEN];
+       int off_cpl;
 
        g_return_if_fail (gtk_widget_get_realized (GTK_WIDGET (gh)));
 
@@ -1087,19 +1091,29 @@ render_offsets (GtkHex *gh,
        max_lines = MIN(max_lines, gh->vis_lines);
        max_lines = MIN(max_lines, gh->lines - gh->top_line - 1);
 
+       /* find out how many chars wide our offset column should be based on
+        * how many chars will be in the last offset marker of the screen */
+       
+       snprintf (buf, BUFLEN-1, "%lX", (gh->top_line + max_lines - 1) * gh->cpl);
+       off_cpl = MAX (MIN_CPL, strlen (buf));
+       snprintf (fmt, BUFLEN-1, "%%0%dlX", off_cpl); 
+       gtk_hex_layout_set_offset_cpl (GTK_HEX_LAYOUT(gh->layout_manager), off_cpl);
+
        for (int i = min_lines; i <= max_lines; i++) {
                /* generate offset string and place in temporary buffer */
-               sprintf(offstr, "%08lX",
+               sprintf(off_str, fmt,
                                (gh->top_line + i) * gh->cpl + STARTING_OFFSET);
 
                /* build pango layout for offset line; draw line with gtk. */
-               pango_layout_set_text (gh->olayout, offstr, 8);
+               pango_layout_set_text (gh->olayout, off_str, off_cpl);
                gtk_render_layout (context, cr,
                                /* x: */ 0,
                                /* y: */ i * gh->char_height,
                                gh->olayout);
        }
 }
+#undef BUFLEN
+#undef MIN_CPL
 
 /* draw_func for the hex drawing area
  */