Improve styling and logging for UI font-size zoom

Refine zoom methods in `MainWindow` and font helpers
in `_style` to return `px_size` up the call chain and
log detailed zoom state on each change.

Deats,
- make `_set_qfont_px_size()` return `self.px_size`.
- make `configure_to_dpi()` and `_config_fonts_to_screen()`
  return the new `px_size` up through the call chain.
- add `font_size` to `log.info()` in `zoom_in()`,
  `zoom_out()`, and `reset_zoom()` alongside
  `zoom_step` and `zoom_level(%)`.
- reformat `has_ctrl`/`_has_shift` bitwise checks and
  key-match tuples to multiline style.
- comment out `Shift` modifier requirement for zoom
  hotkeys (now `Ctrl`-only).
- comment out unused `mn_dpi` and `dpi` locals.

Also,
- convert all single-line docstrings to `'''` multiline
  style across zoom and font methods.
- rewrap `configure_to_dpi()` docstring to 67 chars.
- move `from . import _style` to module-level import
  in `_window.py`.
- drop unused `screen` binding in `boundingRect()`.

(this commit msg was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code

piker/ui/_style.py

@@ -79,9 +79,13 @@ class DpiAwareFont:
         self._font_inches: float = None
         self._screen = None
 
-    def _set_qfont_px_size(self, px_size: int) -> None:
+    def _set_qfont_px_size(
+        self,
+        px_size: int,
+    ) -> int:
         self._qfont.setPixelSize(int(px_size))
         self._qfm = QtGui.QFontMetrics(self._qfont)
+        return self.px_size
 
     @property
     def screen(self) -> QtGui.QScreen:
@@ -128,17 +132,18 @@ class DpiAwareFont:
         self,
         screen: QtGui.QScreen | None = None,
         zoom_level: float = 1.0,
-    ):
+    ) -> int:
         '''
-        Set an appropriately sized font size depending on the screen DPI.
+        Set an appropriately sized font size depending on the screen DPI
+        or scale the size according to `zoom_level`.
 
-        If we end up needing to generalize this more here there are resources
+        If we end up needing to generalize this more here there are
-        listed in the script in ``snippets/qt_screen_info.py``.
+        resources listed in the script in
+        ``snippets/qt_screen_info.py``.
 
         '''
         if self._font_size is not None:
-            self._set_qfont_px_size(self._font_size * zoom_level)
+            return self._set_qfont_px_size(self._font_size * zoom_level)
-            return
 
         # NOTE: if no font size set either in the [ui] section of the
         # config or not yet computed from our magic scaling calcs,
@@ -157,7 +162,7 @@ class DpiAwareFont:
             ldpi = pdpi
 
         mx_dpi = max(pdpi, ldpi)
-        mn_dpi = min(pdpi, ldpi)
+        # mn_dpi = min(pdpi, ldpi)
         scale = round(ldpi/pdpi, ndigits=2)
 
         if mx_dpi <= 97:  # for low dpi use larger font sizes
@@ -166,7 +171,7 @@ class DpiAwareFont:
         else:  # hidpi use smaller font sizes
             inches = _font_sizes['hi'][self._font_size_calc_key]
 
-        dpi = mn_dpi
+        # dpi = mn_dpi
 
         mult = 1.0
 
@@ -213,10 +218,10 @@ class DpiAwareFont:
             f"\nOur best guess font size is {font_size}\n"
         )
         # apply the size
-        self._set_qfont_px_size(font_size)
+        return self._set_qfont_px_size(font_size)
 
     def boundingRect(self, value: str) -> QtCore.QRectF:
-        if (screen := self.screen) is None:
+        if self.screen is None:
             raise RuntimeError("You must call .configure_to_dpi() first!")
 
         unscaled_br: QtCore.QRectF = self._qfm.boundingRect(value)
@@ -233,12 +238,22 @@ _font = DpiAwareFont()
 _font_small = DpiAwareFont(_font_size_key='small')
 
 
-def _config_fonts_to_screen(zoom_level: float = 1.0) -> None:
+def _config_fonts_to_screen(
-    'configure global DPI aware font sizes'
+    zoom_level: float = 1.0
+) -> int:
+    '''
+    Configure global DPI aware font size(s).
 
+    If `zoom_level` is provided we apply it to auto-calculated
+    DPI-aware font.
+
+    Return the new `DpiAwareFont.px_size`.
+
+    '''
     global _font, _font_small
     _font.configure_to_dpi(zoom_level=zoom_level)
     _font_small.configure_to_dpi(zoom_level=zoom_level)
+    return _font.px_size
 
 
 def get_fonts() -> tuple[

piker/ui/_window.py

@@ -43,7 +43,11 @@ from piker.ui.qt import (
     QObject,
 )
 from ..log import get_logger
-from ._style import _font_small, hcolor
+from . import _style
+from ._style import (
+    _font_small,
+    hcolor,
+)
 from ._widget import GodWidget
 
 
@@ -73,6 +77,7 @@ class GlobalZoomEventFilter(QObject):
         Filter keyboard events for global zoom shortcuts.
 
         Returns True to filter out (consume) the event, False to pass through.
+
         '''
         if event.type() == QEvent.Type.KeyPress:
             key = event.key()
@@ -82,28 +87,49 @@ class GlobalZoomEventFilter(QObject):
             mods = mods & ~Qt.KeyboardModifier.KeypadModifier
 
             # Check if we have Ctrl+Shift (both required)
-            has_ctrl = bool(mods & Qt.KeyboardModifier.ControlModifier)
+            has_ctrl = bool(
-            has_shift = bool(mods & Qt.KeyboardModifier.ShiftModifier)
+                mods
+                &
+                Qt.KeyboardModifier.ControlModifier
+            )
+            _has_shift = bool(
+                mods
+                &
+                Qt.KeyboardModifier.ShiftModifier
+            )
 
             # Only handle UI zoom if BOTH Ctrl and Shift are pressed
             # For Plus key: user presses Cmd+Shift+Equal (which makes Plus)
             # For Minus key: user presses Cmd+Shift+Minus
-            if has_ctrl and has_shift:
+            if (
+                has_ctrl
+                # and
+                # has_shift
+            ):
                 # Zoom in: Ctrl+Shift+Plus
                 # Note: Plus key usually comes as Key_Equal with Shift modifier
-                if key in (Qt.Key.Key_Plus, Qt.Key.Key_Equal):
+                if key in (
+                    Qt.Key.Key_Plus,
+                    Qt.Key.Key_Equal,
+                ):
                     self.main_window.zoom_in()
                     return True  # consume event
 
                 # Zoom out: Ctrl+Shift+Minus
                 # Note: On some keyboards Shift+Minus produces '_' (Underscore)
-                elif key in (Qt.Key.Key_Minus, Qt.Key.Key_Underscore):
+                elif key in (
+                    Qt.Key.Key_Minus,
+                    Qt.Key.Key_Underscore,
+                ):
                     self.main_window.zoom_out()
                     return True  # consume event
 
                 # Reset zoom: Ctrl+Shift+0
                 # Note: On some keyboards Shift+0 produces ')' (ParenRight)
-                elif key in (Qt.Key.Key_0, Qt.Key.Key_ParenRight):
+                elif key in (
+                    Qt.Key.Key_0,
+                    Qt.Key.Key_ParenRight,
+                ):
                     self.main_window.reset_zoom()
                     return True  # consume event
 
@@ -444,34 +470,69 @@ class MainWindow(QMainWindow):
         event.accept()
 
     def zoom_in(self) -> None:
-        '''Increase UI zoom level.'''
+        '''
-        new_zoom = min(self._zoom_level + self._zoom_step, self._max_zoom)
+        Increase overall UI-widgets zoom level by scaling it the
-        if new_zoom != self._zoom_level:
+        global font sizes.
-            self._zoom_level = new_zoom
-            self._apply_zoom()
-            log.info(f'Zoomed in to {self._zoom_level:.1%}')
 
-    def zoom_out(self) -> None:
+        '''
-        '''Decrease UI zoom level.'''
+        new_zoom: float = min(
-        new_zoom = max(self._zoom_level - self._zoom_step, self._min_zoom)
+            self._zoom_level + self._zoom_step,
+            self._max_zoom,
+        )
         if new_zoom != self._zoom_level:
             self._zoom_level = new_zoom
-            self._apply_zoom()
+            font_size: int = self._apply_zoom()
-            log.info(f'Zoomed out to {self._zoom_level:.1%}')
+            log.info(
+                f'Zoomed in UI\n'
+                f'zoom_step: {self._zoom_step!r}\n'
+                f'zoom_level(%): {self._zoom_level:.1%}\n'
+                f'font_size: {font_size!r}'
+            )
+
+    def zoom_out(self) -> float:
+        '''
+        Decrease UI zoom level.
+
+        '''
+        new_zoom: float = max(self._zoom_level - self._zoom_step, self._min_zoom)
+        if new_zoom != self._zoom_level:
+            self._zoom_level = new_zoom
+            font_size: int = self._apply_zoom()
+            log.info(
+                f'Zoomed out UI\n'
+                f'zoom_step: {self._zoom_step!r}\n'
+                f'zoom_level(%): {self._zoom_level:.1%}\n'
+                f'font_size: {font_size!r}'
+            )
+
+        return new_zoom
 
     def reset_zoom(self) -> None:
-        '''Reset UI zoom to 100%.'''
+        '''
+        Reset UI zoom to 100%.
+
+        '''
         if self._zoom_level != 1.0:
             self._zoom_level = 1.0
-            self._apply_zoom()
+            font_size: int = self._apply_zoom()
-            log.info('Reset zoom to 100%')
+            log.info(
+                f'Reset zoom level\n'
+                f'zoom_step: {self._zoom_step!r}\n'
+                f'zoom_level(%): {self._zoom_level:.1%}\n'
+                f'font_size: {font_size!r}'
+            )
 
-    def _apply_zoom(self) -> None:
+        return self._zoom_level
-        '''Apply current zoom level to all UI elements.'''
-        from . import _style
 
+    def _apply_zoom(self) -> int:
+        '''
+        Apply current zoom level to all UI elements.
+
+        '''
         # reconfigure fonts with zoom multiplier
-        _style._config_fonts_to_screen(zoom_level=self._zoom_level)
+        font_size: int = _style._config_fonts_to_screen(
+            zoom_level=self._zoom_level
+        )
 
         # update status bar styling with new font size
         if self._status_bar:
@@ -500,8 +561,13 @@ class MainWindow(QMainWindow):
             self._refresh_widget_fonts(self.godwidget)
             self.godwidget.update()
 
+        return font_size
+
     def _update_chart_order_panes(self) -> None:
-        '''Update order entry panels in all charts.'''
+        '''
+        Update order entry panels in all charts.
+
+        '''
         if not self.godwidget:
             return