From 322a9c2f74a83603b709497c34ca03edf43c7bfd Mon Sep 17 00:00:00 2001
From: grorp <gregor.parzefall@posteo.de>
Date: Sat, 31 Aug 2024 18:11:56 +0200
Subject: [PATCH] Restore proportional minimap scaling (#15022)

---
 builtin/game/hud.lua          | 11 ++++++++---
 doc/lua_api.md                |  5 +++++
 src/client/hud.cpp            | 13 ++++++++++---
 src/network/networkprotocol.h |  3 ++-
 4 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/builtin/game/hud.lua b/builtin/game/hud.lua
index a2a046848..eaf037e68 100644
--- a/builtin/game/hud.lua
+++ b/builtin/game/hud.lua
@@ -251,12 +251,17 @@ register_builtin_hud_element("minimap", {
 		position = {x = 1, y = 0},
 		alignment = {x = -1, y = 1},
 		offset = {x = -10, y = 10},
-		size = {x = 256, y = 256},
+		size = {x = 0, y = -25},
 	},
 	show_elem = function(player, flags)
+		local proto_ver = core.get_player_information(player:get_player_name()).protocol_version
 		-- Don't add a minimap for clients which already have it hardcoded in C++.
-		return flags.minimap and
-				core.get_player_information(player:get_player_name()).protocol_version >= 44
+		return flags.minimap and proto_ver >= 44
+	end,
+	update_def = function(player, elem_def)
+		local proto_ver = core.get_player_information(player:get_player_name()).protocol_version
+		-- Only use percentage when the client supports it.
+		elem_def.size = proto_ver >= 45 and {x = 0, y = -25} or {x = 256, y = 256}
 	end,
 })
 
diff --git a/doc/lua_api.md b/doc/lua_api.md
index 2e9c57c9e..e6a351918 100644
--- a/doc/lua_api.md
+++ b/doc/lua_api.md
@@ -1809,6 +1809,11 @@ Displays a minimap on the HUD.
 
 * `size`: Size of the minimap to display. Minimap should be a square to avoid
   distortion.
+  * Negative values represent percentages of the screen. If either `x` or `y`
+    is specified as a percentage, the resulting pixel size will be used for
+    both `x` and `y`. Example: On a 1920x1080 screen, `{x = 0, y = -25}` will
+    result in a 270x270 minimap.
+  * Negative values are supported starting with protocol version 45.
 * `alignment`: The alignment of the minimap.
 * `offset`: offset in pixels from position.
 
diff --git a/src/client/hud.cpp b/src/client/hud.cpp
index 261d01c8e..007421f7a 100644
--- a/src/client/hud.cpp
+++ b/src/client/hud.cpp
@@ -568,14 +568,21 @@ void Hud::drawLuaElements(const v3s16 &camera_offset)
 				}
 				break; }
 			case HUD_ELEM_MINIMAP: {
-				if (e->size.X <= 0 || e->size.Y <= 0)
-					break;
 				if (!client->getMinimap())
 					break;
 				// Draw a minimap of size "size"
 				v2s32 dstsize(e->size.X * m_scale_factor,
 				              e->size.Y * m_scale_factor);
-				// (no percent size as minimap would likely be anamorphosed)
+
+				// Only one percentage is supported to avoid distortion.
+				if (e->size.X < 0)
+					dstsize.X = dstsize.Y = m_screensize.X * (e->size.X * -0.01);
+				else if (e->size.Y < 0)
+					dstsize.X = dstsize.Y = m_screensize.Y * (e->size.Y * -0.01);
+
+				if (dstsize.X <= 0 || dstsize.Y <= 0)
+					return;
+
 				v2s32 offset((e->align.X - 1.0) * dstsize.X / 2,
 				             (e->align.Y - 1.0) * dstsize.Y / 2);
 				core::rect<s32> rect(0, 0, dstsize.X, dstsize.Y);
diff --git a/src/network/networkprotocol.h b/src/network/networkprotocol.h
index 0ad82835e..467124f60 100644
--- a/src/network/networkprotocol.h
+++ b/src/network/networkprotocol.h
@@ -225,7 +225,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 		Move default minimap from client-side C++ to server-side builtin Lua
 		[scheduled bump for 5.9.0]
 	PROTOCOL VERSION 45:
-		Reserved for minimap size change
+		Minimap HUD element supports negative size values as percentages
+		[bump for 5.9.1]
 	PROTOCOL VERSION 46:
 		Move default hotbar from client-side C++ to server-side builtin Lua
 		[scheduled bump for 5.10.0]