From 1cd822b825145d921d678c27b0600c78e576826b Mon Sep 17 00:00:00 2001
From: "Danilo M." <danix@danix.xyz>
Date: Mon, 9 Nov 2026 18:13:59 +0100
Subject: feat: virtual monitor setup

---
 deckit/display.py     | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/test_display.py | 25 +++++++++++++++++++++
 2 files changed, 86 insertions(+)
 create mode 100644 deckit/display.py
 create mode 100644 tests/test_display.py

diff --git a/deckit/display.py b/deckit/display.py
new file mode 100644
index 0000000..f4d85f4
--- /dev/null
+++ b/deckit/display.py
@@ -0,0 +1,61 @@
+"""The virtual monitor half: a headless Hyprland output sized to the tablet."""
+
+import json
+import re
+import shutil
+import subprocess
+import sys
+import time
+from pathlib import Path
+
+
+def run(cmd, timeout=2):
+    try:
+        return subprocess.run(cmd, capture_output=True, text=True, timeout=timeout).stdout.strip()
+    except (OSError, subprocess.TimeoutExpired):
+        return ""
+
+
+def tablet_resolution(cfg: dict, adb=None) -> str:
+    res = cfg.get("display", {}).get("resolution", "auto")
+    if res != "auto":
+        return res
+    read = adb or (lambda: run(["adb", "shell", "wm", "size"]))
+    m = re.search(r"(\d+)x(\d+)", read())
+    if not m:
+        sys.exit("Could not read the tablet resolution; set display.resolution in the config")
+    w, h = sorted(map(int, m.groups()), reverse=True)
+    return f"{w}x{h}"
+
+
+def hypr_lua(cfg: dict) -> bool:
+    mode = cfg.get("hyprland", "auto")
+    if mode == "auto":
+        return (Path.home() / ".config/hypr/hyprland.lua").is_file()
+    return mode == "lua"
+
+
+def setup_display(cfg: dict, run_cmd=None) -> None:
+    run_cmd = run_cmd or run
+    d = cfg.get("display", {})
+    mon = d.get("name", "TAB")
+    monitors = json.loads(run_cmd(["hyprctl", "monitors", "-j"]) or "[]")
+    if not any(m["name"] == mon for m in monitors):
+        run_cmd(["hyprctl", "output", "create", "headless", mon])
+        time.sleep(1)
+    mode = f"{tablet_resolution(cfg)}@{d.get('refresh', 60)}"
+    pos = d.get("position", "auto-right")
+    scale = d.get("scale", 1)
+    if hypr_lua(cfg):
+        run_cmd(["hyprctl", "eval",
+                 f'hl.monitor({{output="{mon}", mode="{mode}", position="{pos}", scale={scale}}})'])
+    else:
+        run_cmd(["hyprctl", "keyword", "monitor", f"{mon},{mode},{pos},{scale}"])
+    tool = shutil.which("awww") or shutil.which("swww")
+    if d.get("wallpaper", True) and tool:
+        others = [m["name"] for m in monitors if m["name"] != mon]
+        for line in run_cmd([tool, "query"]).splitlines():
+            if others and others[0] in line and "image: " in line:
+                run_cmd([tool, "img", "-o", mon, line.split("image: ", 1)[1]], timeout=10)
+                break
+    print(f"{mon}: {mode} at {pos}")
diff --git a/tests/test_display.py b/tests/test_display.py
new file mode 100644
index 0000000..b5d5b11
--- /dev/null
+++ b/tests/test_display.py
@@ -0,0 +1,25 @@
+import sys
+from pathlib import Path
+
+sys.path.insert(0, str(Path(__file__).resolve().parent.parent))
+
+import unittest
+
+import deckit.display as display
+
+
+class Resolution(unittest.TestCase):
+    def test_reads_adb(self):
+        self.assertEqual(
+            display.tablet_resolution({"display": {}}, adb=lambda: "Physical size: 1920x1200"),
+            "1920x1200")
+
+    def test_config_override(self):
+        self.assertEqual(
+            display.tablet_resolution({"display": {"resolution": "2560x1600"}},
+                                      adb=lambda: "1920x1200"),
+            "2560x1600")
+
+
+if __name__ == "__main__":
+    unittest.main()
-- 
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