config/lua: add simple layout API (#14258)

Adds a simple layout lua api

1 files changed, 144 insertions, 0 deletions

diff --git a/src/config/lua/layout/LuaLayoutContext.cpp b/src/config/lua/layout/LuaLayoutContext.cpp
new file mode 100644
index 00000000..f7370e1b
--- /dev/null
+++ b/src/config/lua/layout/LuaLayoutContext.cpp
@@ -0,0 +1,144 @@
+#include "LuaLayoutContext.hpp"
+
+#include "LuaLayoutTarget.hpp"
+#include "../bindings/LuaBindingsInternal.hpp"
+
+#include <algorithm>
+#include <cmath>
+#include <string_view>
+
+using namespace Config::Lua::Layouts;
+
+void Config::Lua::Layouts::pushBox(lua_State* L, const CBox& box) {
+    lua_newtable(L);
+    lua_pushnumber(L, box.x);
+    lua_setfield(L, -2, "x");
+    lua_pushnumber(L, box.y);
+    lua_setfield(L, -2, "y");
+    lua_pushnumber(L, box.w);
+    lua_setfield(L, -2, "w");
+    lua_pushnumber(L, box.h);
+    lua_setfield(L, -2, "h");
+}
+
+bool Config::Lua::Layouts::boxFromTable(lua_State* L, int idx, CBox& box) {
+    idx = lua_absindex(L, idx);
+    if (!lua_istable(L, idx))
+        return false;
+
+    auto getNum = [&](const char* key, double& out) -> bool {
+        lua_getfield(L, idx, key);
+        if (!lua_isnumber(L, -1)) {
+            lua_pop(L, 1);
+            return false;
+        }
+        out = lua_tonumber(L, -1);
+        lua_pop(L, 1);
+        return true;
+    };
+
+    return getNum("x", box.x) && getNum("y", box.y) && getNum("w", box.w) && getNum("h", box.h);
+}
+
+static CBox areaFromContext(lua_State* L, int idx) {
+    idx = lua_absindex(L, idx);
+    CBox area;
+    lua_getfield(L, idx, "area");
+    boxFromTable(L, -1, area);
+    lua_pop(L, 1);
+    return area;
+}
+
+static size_t targetCountFromContext(lua_State* L, int idx) {
+    idx          = lua_absindex(L, idx);
+    size_t count = 0;
+    lua_getfield(L, idx, "targets");
+    if (lua_istable(L, -1))
+        count = lua_rawlen(L, -1);
+    lua_pop(L, 1);
+    return count;
+}
+
+static int ctxGridCell(lua_State* L) {
+    const auto AREA = areaFromContext(L, 1);
+    const int  i    = std::max(1, sc<int>(luaL_checkinteger(L, 2)));
+    const int  cols = std::max(1, sc<int>(luaL_checkinteger(L, 3)));
+    int        rows = 0;
+
+    if (lua_gettop(L) >= 4 && lua_isnumber(L, 4))
+        rows = std::max(1, sc<int>(lua_tointeger(L, 4)));
+    else {
+        const auto count = std::max<size_t>(1, targetCountFromContext(L, 1));
+        rows             = std::max(1, sc<int>(std::ceil(sc<double>(count) / sc<double>(cols))));
+    }
+
+    const int row = (i - 1) / cols;
+    const int col = (i - 1) % cols;
+
+    pushBox(L, CBox{AREA.x + AREA.w * col / cols, AREA.y + AREA.h * row / rows, AREA.w / cols, AREA.h / rows}.noNegativeSize());
+    return 1;
+}
+
+static int ctxColumn(lua_State* L) {
+    const auto AREA = areaFromContext(L, 1);
+    const int  i    = std::max(1, sc<int>(luaL_checkinteger(L, 2)));
+    const int  n    = std::max(1, sc<int>(luaL_checkinteger(L, 3)));
+
+    pushBox(L, CBox{AREA.x + AREA.w * (i - 1) / n, AREA.y, AREA.w / n, AREA.h}.noNegativeSize());
+    return 1;
+}
+
+static int ctxRow(lua_State* L) {
+    const auto AREA = areaFromContext(L, 1);
+    const int  i    = std::max(1, sc<int>(luaL_checkinteger(L, 2)));
+    const int  n    = std::max(1, sc<int>(luaL_checkinteger(L, 3)));
+
+    pushBox(L, CBox{AREA.x, AREA.y + AREA.h * (i - 1) / n, AREA.w, AREA.h / n}.noNegativeSize());
+    return 1;
+}
+
+static int ctxSplit(lua_State* L) {
+    CBox area;
+    if (!boxFromTable(L, 2, area))
+        return Config::Lua::Bindings::Internal::configError(L, "ctx:split expects a box table as first argument");
+
+    const std::string_view side  = luaL_checkstring(L, 3);
+    const double           ratio = std::clamp(luaL_checknumber(L, 4), 0.0, 1.0);
+
+    if (side == "left")
+        pushBox(L, CBox{area.x, area.y, area.w * ratio, area.h}.noNegativeSize());
+    else if (side == "right")
+        pushBox(L, CBox{area.x + area.w * (1.0 - ratio), area.y, area.w * ratio, area.h}.noNegativeSize());
+    else if (side == "top" || side == "up")
+        pushBox(L, CBox{area.x, area.y, area.w, area.h * ratio}.noNegativeSize());
+    else if (side == "bottom" || side == "down")
+        pushBox(L, CBox{area.x, area.y + area.h * (1.0 - ratio), area.w, area.h * ratio}.noNegativeSize());
+    else
+        return Config::Lua::Bindings::Internal::configError(L, "ctx:split side must be left, right, top, or bottom");
+
+    return 1;
+}
+
+void Config::Lua::Layouts::pushLayoutContext(lua_State* L, const std::vector<SP<Layout::ITarget>>& targets, const CBox& area) {
+    lua_newtable(L);
+
+    pushBox(L, area);
+    lua_setfield(L, -2, "area");
+
+    lua_newtable(L);
+    int i = 1;
+    for (const auto& target : targets) {
+        pushLayoutTarget(L, target, i);
+        lua_rawseti(L, -2, i++);
+    }
+    lua_setfield(L, -2, "targets");
+
+    lua_pushcfunction(L, ctxGridCell);
+    lua_setfield(L, -2, "grid_cell");
+    lua_pushcfunction(L, ctxColumn);
+    lua_setfield(L, -2, "column");
+    lua_pushcfunction(L, ctxRow);
+    lua_setfield(L, -2, "row");
+    lua_pushcfunction(L, ctxSplit);
+    lua_setfield(L, -2, "split");
+}