From 2095e82f1aee841ea8ecc8debdece852828c0269 Mon Sep 17 00:00:00 2001
From: MihailRis <mexaruc@gmail.com>
Date: Wed, 19 Nov 2025 19:21:09 +0300
Subject: [PATCH] add Canvas.decode static method

---
 src/coders/imageio.cpp                        | 40 +++++++++++++++----
 src/coders/imageio.hpp                        |  3 ++
 .../lua/usertypes/lua_type_canvas.cpp         | 20 ++++++++++
 3 files changed, 55 insertions(+), 8 deletions(-)

diff --git a/src/coders/imageio.cpp b/src/coders/imageio.cpp
index dc9a78b8..b63c65fc 100644
--- a/src/coders/imageio.cpp
+++ b/src/coders/imageio.cpp
@@ -1,3 +1,4 @@
+#define VC_ENABLE_REFLECTION
 #include "imageio.hpp"
 
 #include <functional>
@@ -7,28 +8,34 @@
 #include "io/io.hpp"
 #include "png.hpp"
 
+using namespace imageio;
+
 using image_reader =
     std::function<std::unique_ptr<ImageData>(const ubyte*, size_t)>;
 using image_writer = std::function<void(const std::string&, const ImageData*)>;
 
-static std::unordered_map<std::string, image_reader> readers {
-    {".png", png::load_image},
+static std::unordered_map<ImageFileFormat, image_reader> readers {
+    {ImageFileFormat::PNG, png::load_image},
 };
 
-static std::unordered_map<std::string, image_writer> writers {
-    {".png", png::write_image},
+static std::unordered_map<ImageFileFormat, image_writer> writers {
+    {ImageFileFormat::PNG, png::write_image},
 };
 
 bool imageio::is_read_supported(const std::string& extension) {
-    return readers.find(extension) != readers.end();
+    return extension == ".png";
 }
 
 bool imageio::is_write_supported(const std::string& extension) {
-    return writers.find(extension) != writers.end();
+    return extension == ".png";
 }
 
 std::unique_ptr<ImageData> imageio::read(const io::path& file) {
-    auto found = readers.find(file.extension());
+    ImageFileFormat format;
+    if (!ImageFileFormatMeta.getItem(file.extension().substr(1), format)) {
+        throw std::runtime_error("unsupported image format");
+    }
+    auto found = readers.find(format);
     if (found == readers.end()) {
         throw std::runtime_error(
             "file format is not supported (read): " + file.string()
@@ -44,8 +51,25 @@ std::unique_ptr<ImageData> imageio::read(const io::path& file) {
     }
 }
 
+std::unique_ptr<ImageData> imageio::decode(
+    ImageFileFormat format, util::span<ubyte> src
+) {
+    auto found = readers.find(format);
+    try {
+        return std::unique_ptr<ImageData>(found->second(src.data(), src.size()));
+    } catch (const std::runtime_error& err) {
+        throw std::runtime_error(
+            "could not to decode image: " + std::string(err.what())
+        );
+    }
+}
+
 void imageio::write(const io::path& file, const ImageData* image) {
-    auto found = writers.find(file.extension());
+    ImageFileFormat format;
+    if (!ImageFileFormatMeta.getItem(file.extension().substr(1), format)) {
+        throw std::runtime_error("unsupported image format");
+    }
+    auto found = writers.find(format);
     if (found == writers.end()) {
         throw std::runtime_error(
             "file format is not supported (write): " + file.string()
diff --git a/src/coders/imageio.hpp b/src/coders/imageio.hpp
index e844cf67..782d51f5 100644
--- a/src/coders/imageio.hpp
+++ b/src/coders/imageio.hpp
@@ -6,6 +6,8 @@
 #include "io/fwd.hpp"
 #include "util/Buffer.hpp"
 #include "util/EnumMetadata.hpp"
+#include "util/span.hpp"
+#include "typedefs.hpp"
 
 class ImageData;
 
@@ -25,5 +27,6 @@ namespace imageio {
 
     std::unique_ptr<ImageData> read(const io::path& file);
     void write(const io::path& file, const ImageData* image);
+    std::unique_ptr<ImageData> decode(ImageFileFormat format, util::span<ubyte> src);
     util::Buffer<unsigned char> encode(ImageFileFormat format, const ImageData& image);
 }
diff --git a/src/logic/scripting/lua/usertypes/lua_type_canvas.cpp b/src/logic/scripting/lua/usertypes/lua_type_canvas.cpp
index 25839659..f89c9d5e 100644
--- a/src/logic/scripting/lua/usertypes/lua_type_canvas.cpp
+++ b/src/logic/scripting/lua/usertypes/lua_type_canvas.cpp
@@ -374,6 +374,23 @@ static int l_meta_meta_call(lua::State* L) {
     );
 }
 
+static int l_canvas_decode(lua::State* L) {
+    auto bytes = bytearray_as_string(L, 1);
+    auto formatName = require_lstring(L, 2);
+    imageio::ImageFileFormat format;
+    if (!imageio::ImageFileFormatMeta.getItem(formatName, format)) {
+        throw std::runtime_error("unsupported image format");
+    }
+    return newuserdata<LuaCanvas>(
+        L,
+        nullptr,
+        imageio::decode(
+            format,
+            {reinterpret_cast<const unsigned char*>(bytes.data()), bytes.size()}
+        )
+    );
+}
+
 int LuaCanvas::createMetatable(State* L) {
     createtable(L, 0, 3);
     pushcfunction(L, lua::wrap<l_meta_index>);
@@ -385,5 +402,8 @@ int LuaCanvas::createMetatable(State* L) {
     pushcfunction(L, lua::wrap<l_meta_meta_call>);
     setfield(L, "__call");
     setmetatable(L);
+
+    pushcfunction(L, lua::wrap<l_canvas_decode>);
+    setfield(L, "decode");
     return 1;
 }