piker/ui/_style.py

@@ -182,7 +182,7 @@ class DpiAwareFont:
         # always going to hit that error in range mapping from inches:
         # float to px size: int.
         self._font_inches = inches
-        font_size = math.floor(inches * dpi)
+        font_size = math.floor(inches * pdpi)
 
         log.debug(
             f"screen:{screen.name()}\n"

pyproject.toml

@@ -85,9 +85,6 @@ uis = [
     # TODO: make sure the levenshtein shit compiles on nix..
     # rapidfuzz = {extras = ["speedup"], version = "^0.18.0"}
     "rapidfuzz >=3.2.0, <4.0.0",
-    "qdarkstyle >=3.0.2, <4.0.0",
-    "pyqt6 >=6.7.0, <7.0.0",
-    "pyqtgraph",
 
     # for consideration,
     # - 'visidata'
@@ -118,6 +115,10 @@ dev = [
 
     # ?from git, see below.
     "xonsh",
+    "qdarkstyle >=3.0.2, <4.0.0",
+    "pyqt6 >=6.7.0, <7.0.0",
+    "pyqtgraph",
+
 ]
 
 [tool.pytest.ini_options]

tests/test_dpi_font.py

@@ -0,0 +1,36 @@
+import pytest
+from piker.ui._style import DpiAwareFont
+
+
+class MockScreen:
+    def __init__(self, pdpi, ldpi, name="MockScreen"):
+        self._pdpi = pdpi
+        self._ldpi = ldpi
+        self._name = name
+
+    def physicalDotsPerInch(self):
+        return self._pdpi
+
+    def logicalDotsPerInch(self):
+        return self._ldpi
+
+    def name(self):
+        return self._name
+
+
+@pytest.mark.parametrize(
+    "pdpi, ldpi, expected_px",
+    [
+        (96, 96, 9),       # normal DPI
+        (169, 96, 15),     # HiDPI
+        (120, 96, 10),     # mid-DPI
+    ]
+)
+def test_font_px_size(pdpi, ldpi, expected_px):
+    font = DpiAwareFont()
+    font.configure_to_dpi(screen=MockScreen(pdpi, ldpi))
+
+    px = font.px_size
+    print(f"{pdpi}x{ldpi} DPI -> Computed pixel size: {px}")
+
+    assert px == expected_px