Spec dpi aware font size in inches

piker/ui/_axes.py

@@ -114,7 +114,7 @@ class AxisLabel(pg.GraphicsObject):
         bg_color: str = 'bracket',
         fg_color: str = 'black',
         opacity: int = 0,
-        font_size: Optional[int] = None,
+        font_size_inches: Optional[float] = None,
     ):
         super().__init__(parent)
         self.setFlag(self.ItemIgnoresTransformations)
@@ -126,12 +126,9 @@ class AxisLabel(pg.GraphicsObject):
 
         self._txt_br: QtCore.QRect = None
 
-        self._dpifont = DpiAwareFont()
+        self._dpifont = DpiAwareFont(size_in_inches=font_size_inches)
         self._dpifont.configure_to_dpi(_font._screen)
 
-        if font_size is not None:
-            self._dpifont._set_qfont_px_size(font_size)
-
         self.bg_color = pg.mkColor(hcolor(bg_color))
         self.fg_color = pg.mkColor(hcolor(fg_color))
 

piker/ui/_graphics.py

@@ -11,7 +11,11 @@ from PyQt5 import QtCore, QtGui
 from PyQt5.QtCore import QLineF, QPointF
 
 # from .._profile import timeit
-from ._style import _xaxis_at, hcolor, _font
+from ._style import (
+    _xaxis_at,
+    hcolor,
+    _font,
+)
 from ._axes import YAxisLabel, XAxisLabel, YSticky
 
 
@@ -759,10 +763,10 @@ class L1Labels:
     def __init__(
         self,
         chart: 'ChartPlotWidget',  # noqa
-        # level: float,
         digits: int = 2,
-        font_size: int = 4,
+        font_size_inches: float = 4 / 53.,
     ) -> None:
+
         self.chart = chart
 
         self.bid_label = L1Label(
@@ -771,7 +775,7 @@ class L1Labels:
             # TODO: pass this from symbol data
             digits=digits,
             opacity=1,
-            font_size=font_size,
+            font_size_inches=font_size_inches,
             bg_color='papas_special',
             fg_color='bracket',
             orient_v='bottom',
@@ -784,7 +788,7 @@ class L1Labels:
             # TODO: pass this from symbol data
             digits=digits,
             opacity=1,
-            font_size=font_size,
+            font_size_inches=font_size_inches,
             bg_color='papas_special',
             fg_color='bracket',
             orient_v='top',
@@ -810,7 +814,10 @@ def level_line(
     chart: 'ChartPlogWidget',  # noqa
     level: float,
     digits: int = 1,
-    font_size: int = 4,
+
+    # size 4 font on 4k screen scaled down, so small-ish.
+    font_size_inches: float = 4 / 53.,
+
     **linelabelkwargs
 ) -> LevelLine:
     """Convenience routine to add a styled horizontal line to a plot.
@@ -822,7 +829,7 @@ def level_line(
         # TODO: pass this from symbol data
         digits=digits,
         opacity=1,
-        font_size=font_size,
+        font_size_inches=font_size_inches,
         # TODO: make this take the view's bg pen
         bg_color='papas_special',
         fg_color='default',

piker/ui/_style.py

@@ -1,6 +1,8 @@
 """
 Qt UI styling.
 """
+from typing import Optional
+
 import pyqtgraph as pg
 from PyQt5 import QtCore, QtGui
 from qdarkstyle.palette import DarkPalette
@@ -11,17 +13,19 @@ log = get_logger(__name__)
 
 # chart-wide font
 # font size 6px / 53 dpi (3x scaled down on 4k hidpi)
-_font_inches_we_like = 6 / 53  # px / (px / inch) = inch
+_default_font_inches_we_like = 6 / 53  # px / (px / inch) = inch
+_down_2_font_inches_we_like = 4 / 53
 
 
 class DpiAwareFont:
     def __init__(
         self,
         name: str = 'Hack',
+        size_in_inches: Optional[float] = None,
     ) -> None:
         self.name = name
         self._qfont = QtGui.QFont(name)
-        self._iwl = _font_inches_we_like
+        self._iwl = size_in_inches or _default_font_inches_we_like
         self._qfm = QtGui.QFontMetrics(self._qfont)
         self._physical_dpi = None
         self._screen = None
@@ -71,7 +75,8 @@ class DpiAwareFont:
             unscaled_br.height(),
         )
 
-# use pixel size to be cross-resolution compatible?
+
+# use inches size to be cross-resolution compatible?
 _font = DpiAwareFont()
 
 # TODO: re-compute font size when main widget switches screens?