From 46c5a90ba11fe1222e5f80bce285aeef2d0ac9b7 Mon Sep 17 00:00:00 2001
From: Norman Feske <norman.feske@genode-labs.com>
Date: Tue, 14 Jan 2020 17:57:13 +0100
Subject: [PATCH] nitpicker_gfx: Text_painter::Font::index_at_xpos

This method is useful for finding the character under a mouse position.
---
 repos/os/include/nitpicker_gfx/text_painter.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/repos/os/include/nitpicker_gfx/text_painter.h b/repos/os/include/nitpicker_gfx/text_painter.h
index 80841b479..34794553a 100644
--- a/repos/os/include/nitpicker_gfx/text_painter.h
+++ b/repos/os/include/nitpicker_gfx/text_painter.h
@@ -97,6 +97,20 @@ struct Text_painter
 
 				return result;
 			}
+
+			unsigned index_at_xpos(Genode::Utf8_ptr utf8, unsigned xpos) const
+			{
+				unsigned index = 0;
+				Fixpoint_number x { (int)0 };
+
+				for (; utf8.complete(); utf8 = utf8.next(), index++) {
+					x.value += advance_info(utf8.codepoint()).advance.value;
+					if (x.decimal() > (int)xpos)
+						break;
+				}
+
+				return index;
+			}
 	};