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/*
* Copyright 2024 jacqueline <me@jacqueline.id.au>
*
* SPDX-License-Identifier: GPL-3.0-only
*/
#include "lua_font.hpp"
#include <cstdint>
#include <string>
#include "lauxlib.h"
#include "lua.h"
#include "lvgl.h"
#include "events/event_queue.hpp"
#include "lua/bridge.hpp"
#include "lua/lua_registry.hpp"
#include "lua/lua_thread.hpp"
namespace lua {
[[maybe_unused]] static constexpr char kTag[] = "lua_font";
/* Reads the given file completely into PSRAM. */
static auto readFont(std::string path) -> std::span<uint8_t> {
// This following is a bit C-brained. Sorry.
FILE* f = fopen(path.c_str(), "r");
if (!f) {
return {};
}
uint8_t* data = NULL;
long len = 0;
if (fseek(f, 0, SEEK_END)) {
goto fail;
}
len = ftell(f);
if (len <= 0) {
goto fail;
}
if (fseek(f, 0, SEEK_SET)) {
len = 0;
goto fail;
}
data = reinterpret_cast<uint8_t*>(heap_caps_malloc(len, MALLOC_CAP_SPIRAM));
if (!data) {
len = 0;
goto fail;
}
if (fread(data, 1, len, f) < len) {
heap_caps_free(data);
len = 0;
}
fail:
fclose(f);
return {data, static_cast<size_t>(len)};
}
static auto parseFont(std::span<uint8_t> data) -> lv_font_t* {
if (data.empty()) {
return nullptr;
}
lv_font_t* font = lv_binfont_create_from_buffer(data.data(), data.size());
heap_caps_free(data.data());
return font;
}
auto loadFont(lua_State* L, const char* path, int cb_ref) -> void {
// Most Lua file paths start with "//" in order to deal with LVGL's Windows-y
// approach to paths. Try to handle such paths correctly so that paths in Lua
// code look a bit more consistent.
std::string path_str = path;
if (path_str.starts_with("//")) {
path++;
path_str = path;
}
// Do the file read from the current thread, since the path might be for a
// file in flash, and we can't read from flash in a background task.
auto font_data = readFont(path_str);
Bridge* bridge = Bridge::Get(L);
bridge->services().bg_worker().Dispatch<void>([=]() {
// Do the parsing now that we're in the background.
lv_font_t* font = parseFont(font_data);
// Hop back to the UI task to invoke the Lua callback.
events::Ui().RunOnTask([=] {
// Retrieve the callback by ref, and release the ref.
lua_rawgeti(L, LUA_REGISTRYINDEX, cb_ref);
luaL_unref(L, LUA_REGISTRYINDEX, cb_ref);
// We always invoke the callback, but we don't always have a result.
if (font) {
lua_pushlightuserdata(L, (void*)font);
} else {
lua_pushnil(L);
}
CallProtected(L, 1, 0);
});
});
}
} // namespace lua
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