Always use same default tabheader height

[p-ouellette]

Previously the default tabheader height was different when using
real coordinates. This resulted in the height of tabs changing when
switching tabs in sfinv if some tabs used real coordinates.

To do

This PR is a Ready for Review.

How to test

Apply the patch below to sfinv. Open sfinv and switch between the crafting tab and other tabs (ignore the messed up contents of the crafting tab).
Before this PR: tabheader height changes when switching between crafting tab and other tabs.
After: tabheader hight unchanged between tabs.

diff --git a/mods/sfinv/init.lua b/mods/sfinv/init.lua
index 71e9ee7..47424ea 100644
--- a/mods/sfinv/init.lua
+++ b/mods/sfinv/init.lua
@@ -14,6 +14,6 @@ sfinv.register_page("sfinv:crafting", {
                                image[4.75,1.5;1,1;sfinv_crafting_arrow.png]
                                listring[current_player;main]
                                listring[current_player;craft]
-                       ]], true)
+                       ]], true, "formspec_version[3]size[10.5,11.375]")
        end
 })

Note: the form width of 10.5 comes from the conversion formula in lua_api.txt, but that formula did not give the correct height (I arrived at 11.375 by guess and check, the formula suggested 11.875). Not sure what's going on there.

[rubenwardy]

This code is valid and works, but I'm trying to think of a better way to structure it. Having the string -> float conversion in v_geom is annoying to my logic. This is as far I got:

// Work out the formspec-coordinate size, if in real-coordinates mode
bool auto_width = true;
std::vector<std::string> v_geom = {"1", "1"}; // Dummy width and height
if (data->real_coordinates) {
	if (parts.size() == 7) {
		i++;

		v_geom = split(parts[1], ',');
		if (v_geom.size() == 1)
			v_geom.insert(v_geom.begin(), std::to_string(2.f * (float)m_btn_height / (float)imgsize.Y));
		else
			auto_width = false;
	} else {
		v_geom[1] = std::to_string(2.f * (float)m_btn_height / (float)imgsize.Y);
	}
}

I was attempting to get the formspec parsing done in one place, so that the formspec coord -> irrlicht coord conversion part wouldn't care about it

[rubenwardy]

perhaps:

// Work out the formspec-coordinate size, if in real-coordinates mode
const auto default_height = std::to_string(2.f * (float)m_btn_height / (float)imgsize.Y);
bool auto_width = true;
std::vector<std::string> v_geom = {"1", default_height};
if (parts.size() == 7) {
	i++;

	v_geom = split(parts[1], ',');
	if (v_geom.size() == 1)
		v_geom.insert(v_geom.begin(), default_height);
	else
		auto_width = false;
}

[sfan5]

Looks good.

[SmallJoker]

Works.