fix(wgc): preserve full-width display identifiers

electron/native/wgc-capture/src/main.cpp

@@ -24,7 +24,7 @@ static std::mutex g_stopMutex;
 static std::condition_variable g_stopCv;
 
 struct CaptureConfig {
-    int displayId = 0;
+    int64_t displayId = 0;
     int64_t windowHandle = 0;
     std::string outputPath;
     std::string audioOutputPath;
@@ -96,7 +96,7 @@ static bool parseSimpleJson(const std::string& json, CaptureConfig& config) {
     config.outputPath = findString("outputPath");
     if (config.outputPath.empty()) return false;
 
-    int displayId = findInt("displayId");
+    int64_t displayId = findInt64("displayId");
     if (displayId >= 0) config.displayId = displayId;
 
     int64_t windowHandle = findInt64("windowHandle");

electron/native/wgc-capture/src/monitor_utils.cpp

@@ -27,20 +27,16 @@ std::vector<MonitorInfo> enumerateMonitors() {
 }
 
 // Electron uses the HMONITOR handle value cast to a number as the display ID.
-HMONITOR findMonitorByDisplayId(int displayId) {
+HMONITOR findMonitorByDisplayId(int64_t displayId) {
     auto monitors = enumerateMonitors();
 
     for (const auto& m : monitors) {
-        if (static_cast<int>(reinterpret_cast<intptr_t>(m.handle)) == displayId) {
+        if (static_cast<int64_t>(reinterpret_cast<intptr_t>(m.handle)) == displayId) {
             return m.handle;
         }
     }
 
-    if (!monitors.empty()) {
-        return monitors[0].handle;
-    }
-
-    return MonitorFromPoint({0, 0}, MONITOR_DEFAULTTOPRIMARY);
+    return nullptr;
 }
 
 MonitorInfo getMonitorInfo(HMONITOR monitor) {

electron/native/wgc-capture/src/monitor_utils.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <cstdint>
 #include <windows.h>
 #include <string>
 #include <vector>
@@ -14,5 +15,5 @@ struct MonitorInfo {
 };
 
 std::vector<MonitorInfo> enumerateMonitors();
-HMONITOR findMonitorByDisplayId(int displayId);
+HMONITOR findMonitorByDisplayId(int64_t displayId);
 MonitorInfo getMonitorInfo(HMONITOR monitor);