Add displayinfo_linux.cpp — Linux display enumeration using xrandr subprocess

src/wg/displayinfo_linux.cpp

@@ -0,0 +1,122 @@
+// src/wg/displayinfo_linux.cpp — Linux implementation of display enumeration.
+//
+// Uses xrandr subprocess to query connected displays.
+// Parses lines matching: <output-name> connected [primary] <WxH>+<x>+<y>
+
+#include "displayinfo.h"
+
+#if defined(__linux__)
+
+#include <cstdio>
+#include <cstring>
+#include <string>
+#include <vector>
+
+namespace wg {
+
+std::vector<DisplayInfo> enumerateDisplays() {
+    std::vector<DisplayInfo> displays;
+
+    FILE *fp = popen("xrandr --query 2>/dev/null", "r");
+    if (!fp) {
+        // Fallback: return default display
+        DisplayInfo def;
+        def.name = "default";
+        def.friendlyName = "default";
+        def.width = 1920;
+        def.height = 1080;
+        def.isPrimary = true;
+        displays.push_back(def);
+        return displays;
+    }
+
+    char line[512];
+    while (fgets(line, sizeof(line), fp) != nullptr) {
+        // Remove trailing newline
+        size_t len = strlen(line);
+        if (len > 0 && line[len - 1] == '\n') {
+            line[len - 1] = '\0';
+        }
+
+        // Skip lines that don't look like output lines (no "connected")
+        if (strstr(line, "connected") == nullptr) {
+            continue;
+        }
+
+        // Parse: <name> connected [primary] <resolution>
+        char name[128] = {};
+        char resolution[64] = {};
+        int isPrimary = 0;
+
+        // Extract name (first token before space)
+        char *space = strchr(line, ' ');
+        if (!space) continue;
+        size_t nameLen = space - line;
+        if (nameLen >= sizeof(name)) nameLen = sizeof(name) - 1;
+        memcpy(name, line, nameLen);
+        name[nameLen] = '\0';
+
+        // Check if "primary" is in the line
+        if (strstr(line, "primary") != nullptr) {
+            isPrimary = 1;
+        }
+
+        // Extract resolution: look for pattern like "1920x1080"
+        char *res = strstr(line, "1280x720");
+        if (!res) res = strstr(line, "1920x1080");
+        if (!res) res = strstr(line, "2560x1440");
+        if (!res) res = strstr(line, "3840x2160");
+        if (!res) {
+            // More general: look for digits followed by 'x' and more digits
+            res = line;
+            while (*res) {
+                if (isdigit(*res)) {
+                    char *xpos = strchr(res, 'x');
+                    if (xpos && isdigit(xpos[1])) {
+                        break;
+                    }
+                }
+                res++;
+            }
+            if (!*res) continue;
+        }
+
+        int w = 0, h = 0;
+        if (sscanf(res, "%dx%d", &w, &h) != 2) {
+            continue;
+        }
+
+        // Only add if we have valid dimensions
+        if (w <= 0 || h <= 0) {
+            continue;
+        }
+
+        DisplayInfo info;
+        info.name = std::string(name);
+        info.friendlyName = std::string(name);
+        info.width = w;
+        info.height = h;
+        info.isPrimary = isPrimary != 0;
+
+        displays.push_back(info);
+    }
+
+    pclose(fp);
+
+    // If xrandr returned nothing, fallback to default
+    if (displays.empty()) {
+        DisplayInfo def;
+        def.name = "default";
+        def.friendlyName = "default";
+        def.width = 1920;
+        def.height = 1080;
+        def.isPrimary = true;
+        displays.push_back(def);
+    }
+
+    return displays;
+}
+
+} // namespace wg
+
+#endif // defined(__linux__)