CrealityPrint: add multi-color print protocol for K2 Plus

For supported models, start_print() sends colorMatch (filament-to-slot
mapping) followed by multiColorPrint (with optional calibration via
enableSelfTest) instead of the legacy opGcodeFile command. The dialog
passes color mapping and calibration settings through extended_info.

Signed-off-by: Igor Mammedov <niallain@gmail.com>
---
v4:
- Skip "path" form field in multipart upload for multi-color printers
  (extra field breaks K2 Plus firmware parser)
- Use fire-and-forget ws.write() for colorMatch and multiColorPrint
  instead of ws_send_and_read() (printer sends response asynchronously)

src/slic3r/Utils/CrealityPrint.cpp

@@ -140,15 +140,16 @@ bool CrealityPrint::upload(PrintHostUpload upload_data, ProgressFn prorgess_fn,
 
     auto  http = Http::post(url); // std::move(url));
     set_auth(http);
-    http.form_add("path", upload_parent_path.string())
+    if (!supports_multi_color_print())
-        .form_add_file("file", upload_data.source_path.string(), upload_filename.string())
+        http.form_add("path", upload_parent_path.string());
+    http.form_add_file("file", upload_data.source_path.string(), upload_filename.string())
 
         .on_complete([&](std::string body, unsigned status) {
             BOOST_LOG_TRIVIAL(debug) << boost::format("%1%: File uploaded: HTTP %2%: %3%") % name % status % body;
 
             if (upload_data.post_action == PrintHostPostUploadAction::StartPrint) {
                 wxString errormsg;
-                if (!start_print(errormsg, safe_filename(upload_filename.string()))) {
+                if (!start_print(errormsg, safe_filename(upload_filename.string()), upload_data.extended_info)) {
                     error_fn(std::move(errormsg));
                     res = false;
                 }
@@ -278,28 +279,81 @@ std::string CrealityPrint::query_boxes_info() const
     }
 }
 
-bool CrealityPrint::start_print(wxString &msg, const std::string &filename) const
+bool CrealityPrint::start_print(wxString &msg, const std::string &filename, const std::map<std::string, std::string>& extended_info) const
 {
     try {
+        const std::string gcode_path = "/mnt/UDISK/printer_data/gcodes/" + filename;
+
         net::io_context ioc;
         websocket::stream<beast::tcp_stream> ws{ioc};
         ws_connect(ioc, ws, m_host, "9999");
 
-        json j2 = {
+        if (supports_multi_color_print()) {
-            { "method", "set" },
+            // Build colorMatch list from the mapping provided by the dialog
-            {
+            json color_list = json::array();
-                "params", {
+            for (int i = 0; ; i++) {
-                    { "opGcodeFile", "printprt:/usr/data/printer_data/gcodes/" + filename }
+                auto it = extended_info.find("colorMatch_" + std::to_string(i));
+                if (it == extended_info.end())
+                    break;
+                // Value format: "toolId\ttype\tcolor\tboxId\tmaterialId"
+                auto val = it->second;
+                std::vector<std::string> parts;
+                std::istringstream iss(val);
+                std::string part;
+                while (std::getline(iss, part, '\t'))
+                    parts.push_back(part);
+                if (parts.size() >= 5) {
+                    color_list.push_back({
+                        {"id", parts[0]},
+                        {"type", parts[1]},
+                        {"color", parts[2]},
+                        {"boxId", std::stoi(parts[3])},
+                        {"materialId", std::stoi(parts[4])}
+                    });
                 }
             }
-        };
 
-        ws.write(net::buffer(to_string(j2)));
+            json color_match = {
+                {"method", "set"},
+                {"params", {
+                    {"colorMatch", {
+                        {"path", gcode_path},
+                        {"list", color_list}
+                    }}
+                }}
+            };
+            ws.write(net::buffer(to_string(color_match)));
 
-        beast::flat_buffer buffer;
+            // Read enableSelfTest from extended_info, default to 0 (calibration off)
+            int enable_self_test = 0;
+            auto it = extended_info.find("enableSelfTest");
+            if (it != extended_info.end())
+                enable_self_test = std::stoi(it->second);
 
-        ws.read(buffer);
+            json multi_color_print = {
+                {"method", "set"},
+                {"params", {
+                    {"multiColorPrint", {
+                        {"gcode", gcode_path},
+                        {"enableSelfTest", enable_self_test}
+                    }}
+                }}
+            };
+            ws.write(net::buffer(to_string(multi_color_print)));
+        } else {
+            json cmd = {
+                {"method", "set"},
+                {"params", {
+                    {"opGcodeFile", "printprt:/usr/data/printer_data/gcodes/" + filename}
+                }}
+            };
+            ws.write(net::buffer(to_string(cmd)));
 
+            beast::flat_buffer buffer;
+            ws.read(buffer);
+        }
+
+        ws.close(websocket::close_code::normal);
         return true;
     } catch(std::exception const& e) {
         BOOST_LOG_TRIVIAL(error) << "CrealityPrint: Error starting print: " << e.what();

src/slic3r/Utils/CrealityPrint.hpp

@@ -1,6 +1,7 @@
 #ifndef slic3r_CrealityPrint_hpp_
 #define slic3r_CrealityPrint_hpp_
 
+#include <map>
 #include <string>
 #include <wx/string.h>
 #include <boost/optional.hpp>
@@ -44,7 +45,7 @@ private:
     mutable std::string m_model;
 
     std::string make_url(const std::string& path) const;
-    bool start_print(wxString& msg, const std::string& path) const;
+    bool start_print(wxString& msg, const std::string& filename, const std::map<std::string, std::string>& extended_info) const;
     std::string safe_filename(const std::string& filename) const;
     void query_model() const;
 };