fix: handle scroll_cursor_min_border_distance values larger than half the view height

And fix an off-by-one issue causing the distance at the bottom of the view
to be one line less than the top.

close #506

src/buffer/View.zig

@@ -9,7 +9,7 @@ col: usize = 0,
 rows: usize = 0,
 cols: usize = 0,
 
-const scroll_cursor_min_border_distance = 5;
+pub var scroll_cursor_min_border_distance: usize = 5;
 const scroll_cursor_min_border_distance_mouse = 1;
 
 const Self = @This();
@@ -65,7 +65,7 @@ inline fn is_at_top(self: *const Self) bool {
 
 inline fn is_at_bottom(self: *const Self, root: Buffer.Root) bool {
     if (root.lines() < self.rows) return true;
-    return self.row >= root.lines() - scroll_cursor_min_border_distance;
+    return self.row >= root.lines() -| scroll_cursor_min_border_distance;
 }
 
 pub inline fn is_visible(self: *const Self, cursor: *const Cursor) bool {
@@ -96,7 +96,7 @@ inline fn to_cursor_bottom(self: *const Self, root: Buffer.Root) Cursor {
 
 fn clamp_row(self: *Self, cursor: *const Cursor, abs: bool, bottom_offset: usize) void {
     const top_min_border_distance: usize = if (abs) scroll_cursor_min_border_distance_mouse else scroll_cursor_min_border_distance;
-    const bottom_min_border_distance: usize = top_min_border_distance + bottom_offset;
+    const bottom_min_border_distance: usize = top_min_border_distance + bottom_offset + 1;
     if (cursor.row < top_min_border_distance) {
         self.row = 0;
         return;

src/tui/editor.zig

@@ -2987,7 +2987,7 @@ pub const Editor = struct {
     }
 
     pub fn update_scroll_dest_abs(self: *Self, dest: usize) void {
-        const scroll_cursor_min_border_distance = tui.config().scroll_cursor_min_border_distance;
+        const scroll_cursor_min_border_distance = Buffer.View.scroll_cursor_min_border_distance;
         const root = self.buf_root() catch return;
         const max_view = if (root.lines() <= scroll_cursor_min_border_distance) 0 else root.lines() - scroll_cursor_min_border_distance;
         self.scroll_dest = @min(dest, max_view);
@@ -3057,7 +3057,7 @@ pub const Editor = struct {
     pub const scroll_view_center_meta: Meta = .{ .description = "Scroll cursor to center of view" };
 
     pub fn scroll_view_center_cycle(self: *Self, _: Context) Result {
-        const scroll_cursor_min_border_distance = tui.config().scroll_cursor_min_border_distance;
+        const scroll_cursor_min_border_distance = Buffer.View.scroll_cursor_min_border_distance;
         const cursor_row = self.get_primary().cursor.row;
         return if (cursor_row == self.view.row + scroll_cursor_min_border_distance)
             self.scroll_view_bottom(.{})
@@ -3069,14 +3069,14 @@ pub const Editor = struct {
     pub const scroll_view_center_cycle_meta: Meta = .{ .description = "Scroll cursor to center/top/bottom of view" };
 
     pub fn scroll_view_top(self: *Self, _: Context) Result {
-        const scroll_cursor_min_border_distance = tui.config().scroll_cursor_min_border_distance;
+        const scroll_cursor_min_border_distance = Buffer.View.scroll_cursor_min_border_distance;
         return self.scroll_view_offset(scroll_cursor_min_border_distance);
     }
     pub const scroll_view_top_meta: Meta = .{};
 
     pub fn scroll_view_bottom(self: *Self, _: Context) Result {
-        const scroll_cursor_min_border_distance = tui.config().scroll_cursor_min_border_distance;
-        return self.scroll_view_offset(if (self.view.rows > scroll_cursor_min_border_distance) self.view.rows - scroll_cursor_min_border_distance else 0);
+        const scroll_cursor_min_border_distance = Buffer.View.scroll_cursor_min_border_distance;
+        return self.scroll_view_offset(if (self.view.rows > scroll_cursor_min_border_distance) self.view.rows -| scroll_cursor_min_border_distance + 1 else 0);
     }
     pub const scroll_view_bottom_meta: Meta = .{};
 
@@ -6386,7 +6386,7 @@ pub const Editor = struct {
         const cursor = sel.begin;
         const range_height = sel.end.row - sel.begin.row + 1;
         const view_height = self.view.rows;
-        const scroll_cursor_min_border_distance = tui.config().scroll_cursor_min_border_distance;
+        const scroll_cursor_min_border_distance = Buffer.View.scroll_cursor_min_border_distance;
         const offset = if (range_height > view_height - @min(view_height, scroll_cursor_min_border_distance * 2))
             scroll_cursor_min_border_distance
         else
@@ -6416,7 +6416,7 @@ pub const Editor = struct {
         primary.cursor = cursor;
         const range_height = sel.end.row - sel.begin.row + 1;
         const view_height = self.view.rows;
-        const scroll_cursor_min_border_distance = tui.config().scroll_cursor_min_border_distance;
+        const scroll_cursor_min_border_distance = Buffer.View.scroll_cursor_min_border_distance;
         const offset = if (range_height > view_height - @min(view_height, scroll_cursor_min_border_distance * 2))
             scroll_cursor_min_border_distance
         else

src/tui/tui.zig

@@ -1949,7 +1949,11 @@ pub fn frames_rendered() usize {
 }
 
 pub fn resize() void {
-    mainview_widget().resize(screen());
+    const self = current();
+    const scr = screen();
+    const half_scr = (scr.h -| 2) / 2;
+    Buffer.View.scroll_cursor_min_border_distance = @min(half_scr, self.config_.scroll_cursor_min_border_distance);
+    mainview_widget().resize(scr);
     refresh_hover(@src());
     need_render(@src());
 }