terminal: scroll up full top/bottom region was off by one

Fixes #689

See test cases, verified with xterm.

src/terminal/Terminal.zig

@@ -1765,7 +1765,7 @@ pub fn deleteLines(self: *Terminal, count: usize) !void {
         self.screen.scrollRegionUp(
             .{ .active = self.screen.cursor.y },
             .{ .active = self.scrolling_region.bottom },
-            @min(count, self.scrolling_region.bottom - self.screen.cursor.y),
+            @min(count, (self.scrolling_region.bottom - self.screen.cursor.y) + 1),
         );
         return;
     }
@@ -6364,6 +6364,44 @@ test "Terminal: scrollUp preserves pending wrap" {
     }
 }
 
+test "Terminal: scrollUp full top/bottom region" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 5, 5);
+    defer t.deinit(alloc);
+
+    try t.printString("top");
+    t.setCursorPos(5, 1);
+    try t.printString("ABCDE");
+    t.setTopAndBottomMargin(2, 5);
+    try t.scrollUp(4);
+
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings("top", str);
+    }
+}
+
+test "Terminal: scrollUp full top/bottomleft/right scroll region" {
+    const alloc = testing.allocator;
+    var t = try init(alloc, 5, 5);
+    defer t.deinit(alloc);
+
+    try t.printString("top");
+    t.setCursorPos(5, 1);
+    try t.printString("ABCDE");
+    t.modes.set(.enable_left_and_right_margin, true);
+    t.setTopAndBottomMargin(2, 5);
+    t.setLeftAndRightMargin(2, 4);
+    try t.scrollUp(4);
+
+    {
+        var str = try t.plainString(testing.allocator);
+        defer testing.allocator.free(str);
+        try testing.expectEqualStrings("top\n\n\n\nA   E", str);
+    }
+}
+
 test "Terminal: tabClear single" {
     const alloc = testing.allocator;
     var t = try init(alloc, 30, 5);

src/termio/Exec.zig

@@ -469,6 +469,8 @@ pub inline fn queueWrite(self: *Exec, data: []const u8, linefeed: bool) !void {
             break :slice buf[0..buf_i];
         };
 
+        // for (slice) |b| log.warn("write: {x}", .{b});
+
         ev.data_stream.queueWrite(
             ev.loop,
             &ev.write_queue,

website/app/vt/su/page.mdx

@@ -95,3 +95,19 @@ printf "X"
 |________|
 |X_______|
 ```
+
+### SU V-5: Scroll Full Top/Bottom Scroll Region
+
+```bash
+printf "\033[1;1H" # move to top-left
+printf "\033[0J" # clear screen
+printf "top"
+printf "\033[5;1H"
+printf "ABCDEF"
+printf "\033[2;5r" # scroll region top/bottom
+printf "\033[4S"
+```
+
+```
+|top_____|
+```