Add `font_size` param to `AnnotCtl.add_text()` API

Expose font sizing control for `pg.TextItem` annotations thru the
annot-ctl API. Default to `_font.font.pixelSize() - 3` when no
size provided.

Also,
- thread `font_size` param thru IPC handler in `serve_rc_annots()`
- apply font via `QFont.setPixelSize()` on text item creation
- add `?TODO` note in `markup_gaps()` re using `conf.toml` value
- update `add_text()` docstring with font_size param desc

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

piker/tsp/_annotate.py

@@ -30,6 +30,7 @@ import tractor
 
 from piker.data._formatters import BGM
 from piker.storage import log
+# from piker.ui._style import _font
 
 if TYPE_CHECKING:
     from piker.ui._remote_ctl import AnnotCtl
@@ -236,6 +237,14 @@ async def markup_gaps(
         else:  # down-gap
             anchor = (0, 1)  # XXX y, x?
 
+        # ?TODO? why returning -1 !?
+        # [ ] use conf.toml value instead!
+        #
+        # font_size: int = _font.font.pixelSize() - 10
+        # await tractor.pause()
+        # assert isinstance(font_size, int)
+        font_size = None
+
         text_aid: int = await actl.add_text(
             fqme=fqme,
             timeframe=timeframe,
@@ -244,6 +253,7 @@ async def markup_gaps(
             y=cls,
             color=color,
             anchor=anchor,
+            font_size=font_size,
         )
         aids[text_aid] = {'text': gap_label}
 

piker/ui/_remote_ctl.py

@@ -48,8 +48,8 @@ from piker.service import find_service
 from piker.brokers import SymbolNotFound
 from piker.ui.qt import (
     QGraphicsItem,
-    QColor,
 )
+from PyQt6.QtGui import QFont
 from ._display import DisplayState
 from ._interaction import ChartView
 from ._editors import (
@@ -248,6 +248,7 @@ async def serve_rc_annots(
                     'y': int()|float() as y,
                     'color': color,
                     'anchor': list(anchor),
+                    'font_size': int()|None as font_size,
                 },
             }:
                 ds: DisplayState = _dss[fqme]
@@ -264,7 +265,22 @@ async def serve_rc_annots(
                     text=text,
                     color=color_hex,
                     anchor=anchor,
+
+                    # ?TODO, pin to github:main for this?
+                    # legacy, can have scaling ish?
+                    # ensureInBounds=True,
                 )
+
+                # apply font size (default to DpiAwareFont if not
+                # provided)
+                if font_size is None:
+                    from ._style import _font
+                    font_size =  _font.font.pixelSize() - 3
+
+                qfont: QFont = text_item.textItem.font()
+                qfont.setPixelSize(font_size)
+                text_item.setFont(qfont)
+
                 text_item.setPos(x, y)
                 chart.plotItem.addItem(text_item)
 
@@ -547,6 +563,7 @@ class AnnotCtl(Struct):
         y: float,
         color: str|tuple = 'dad_blue',
         anchor: tuple[float, float] = (0, 1),
+        font_size: int|None = None,
 
         from_acm: bool = False,
 
@@ -555,6 +572,7 @@ class AnnotCtl(Struct):
         Add a `pg.TextItem` annotation to the target view.
 
         anchor: (x, y) where (0,0) is upper-left, (1,1) is lower-right
+        font_size: pixel size for font, defaults to `_font.font.pixelSize()`
 
         '''
         ipc: MsgStream = self._get_ipc(fqme)
@@ -568,6 +586,7 @@ class AnnotCtl(Struct):
                 'y': float(y),
                 'color': color,
                 'anchor': tuple(anchor),
+                'font_size': font_size,
             },
         })
         aid: int = await ipc.receive()