Tidy axis code

piker/ui/_axes.py

@@ -16,6 +16,7 @@
 
 """
 Chart axes graphics and behavior.
+
 """
 
 from typing import List, Tuple, Optional
@@ -32,7 +33,7 @@ _axis_pen = pg.mkPen(hcolor('bracket'))
 
 
 class Axis(pg.AxisItem):
-    """A better axis that sizes to typical tick contents considering font size.
+    """A better axis that sizes tick contents considering font size.
 
     """
     def __init__(
@@ -64,11 +65,17 @@ class Axis(pg.AxisItem):
         self.typical_br = _font._qfm.boundingRect(typical_max_str)
 
         # size the pertinent axis dimension to a "typical value"
-        self.resize()
+        self.size_to_values()
+
+    def size_to_values(self) -> None:
+        pass
 
     def set_min_tick(self, size: int) -> None:
         self._min_tick = size
 
+    def txt_offsets(self) -> Tuple[int, int]:
+        return tuple(self.style['tickTextOffset'])
+
 
 class PriceAxis(Axis):
 
@@ -77,13 +84,13 @@ class PriceAxis(Axis):
         *args,
         **kwargs,
     ) -> None:
-        super().__init__(*args, orientation='right', **kwargs)
+        super().__init__(*args, **kwargs)
         self.setStyle(**{
             # offset of text *away from* axis line in px
             'tickTextOffset': 9,
         })
 
-    def resize(self) -> None:
+    def size_to_values(self) -> None:
         self.setWidth(self.typical_br.width())
 
     # XXX: drop for now since it just eats up h space
@@ -116,7 +123,7 @@ class DynamicDateAxis(Axis):
         1: '%H:%M:%S',
     }
 
-    def resize(self) -> None:
+    def size_to_values(self) -> None:
         self.setHeight(self.typical_br.height() + 1)
 
     def _indexes_to_timestrs(
@@ -160,22 +167,28 @@ class AxisLabel(pg.GraphicsObject):
 
     def __init__(
         self,
-        parent: Axis,
+        parent: pg.GraphicsItem,
         digits: int = 2,
+
+        font_size_inches: Optional[float] = None,
         bg_color: str = 'bracket',
         fg_color: str = 'black',
-        opacity: int = 0,
+        opacity: int = 1,  # XXX: seriously don't set this to 0
+
         use_arrow: bool = True,
-        font_size_inches: Optional[float] = None,
+
     ) -> None:
 
-        super().__init__(parent)
+        super().__init__()
+        self.setParentItem(parent)
+
         self.setFlag(self.ItemIgnoresTransformations)
 
         # XXX: pretty sure this is faster
         self.setCacheMode(QtGui.QGraphicsItem.DeviceCoordinateCache)
 
-        self.parent = parent
+        self._parent = parent
+
         self.opacity = opacity
         self.label_str = ''
         self.digits = digits
@@ -200,6 +213,11 @@ class AxisLabel(pg.GraphicsObject):
         opt: QtWidgets.QStyleOptionGraphicsItem,
         w: QtWidgets.QWidget
     ) -> None:
+        """Draw a filled rectangle based on the size of ``.label_str`` text.
+
+        Subtypes can customize further by overloading ``.draw()``.
+
+        """
         # p.setCompositionMode(QtGui.QPainter.CompositionMode_SourceOver)
 
         if self.label_str:
@@ -207,37 +225,41 @@ class AxisLabel(pg.GraphicsObject):
             # if not self.rect:
             self._size_br_from_str(self.label_str)
 
-            p.setFont(self._dpifont.font)
-            p.setPen(self.fg_color)
-            p.setOpacity(self.opacity)
-
             # can be overrided in subtype
             self.draw(p, self.rect)
 
+            p.setFont(self._dpifont.font)
+            p.setPen(self.fg_color)
             p.drawText(self.rect, self.text_flags, self.label_str)
 
+
     def draw(
         self,
         p: QtGui.QPainter,
         rect: QtCore.QRectF
     ) -> None:
-        # this adds a nice black outline around the label for some odd
-        # reason; ok by us
-        # p.setOpacity(self.opacity)
-        p.drawRect(self.rect)
 
         if self._use_arrow:
-
             if not self.path:
                 self._draw_arrow_path()
 
             p.drawPath(self.path)
             p.fillPath(self.path, pg.mkBrush(self.bg_color))
 
+        # this adds a nice black outline around the label for some odd
+        # reason; ok by us
+        p.setOpacity(self.opacity)
+
+        # this cause the L1 labels to glitch out if used 
+        # in the subtype and it will leave a small black strip
+        # with the arrow path if done before the above
         p.fillRect(self.rect, self.bg_color)
 
 
     def boundingRect(self):  # noqa
+        """Size the graphics space from the text contents.
+
+        """
         if self.label_str:
             self._size_br_from_str(self.label_str)
 
@@ -267,12 +289,14 @@ class AxisLabel(pg.GraphicsObject):
 
         txt_br = self._txt_br = self._dpifont.boundingRect(value)
         txt_h, txt_w = txt_br.height(), txt_br.width()
+
+        # allow subtypes to specify a static width and height
         h, w = self.size_hint()
 
         self.rect = QtCore.QRectF(
             0, 0,
-            (w or txt_w) + self._x_margin/2,
+            (w or txt_w) + self._x_margin /2,
-            (h or txt_h) + self._y_margin/2,
+            (h or txt_h) + self._y_margin /2,
         )
         # print(self.rect)
         # hb = self.path.controlPointRect()
@@ -299,7 +323,7 @@ class XAxisLabel(AxisLabel):
 
     def size_hint(self) -> Tuple[float, float]:
         # size to parent axis height
-        return self.parent.height(), None
+        return self._parent.height(), None
 
     def update_label(
         self,
@@ -308,7 +332,7 @@ class XAxisLabel(AxisLabel):
         offset: int = 0  # if have margins, k?
     ) -> None:
 
-        timestrs = self.parent._indexes_to_timestrs([int(value)])
+        timestrs = self._parent._indexes_to_timestrs([int(value)])
 
         if not timestrs.any():
             return
@@ -316,9 +340,10 @@ class XAxisLabel(AxisLabel):
         pad = 1*' '
         self.label_str = pad + timestrs[0] + pad
 
-        y_offset = self.parent.style['tickTextOffset'][1]
+        _, y_offset = self._parent.txt_offsets()
 
         w = self.boundingRect().width()
+
         self.setPos(QPointF(
             abs_pos.x() - w/2,
             y_offset/2,
@@ -326,13 +351,10 @@ class XAxisLabel(AxisLabel):
         self.update()
 
     def _draw_arrow_path(self):
-        y_offset = self.parent.style['tickTextOffset'][1]
+        y_offset = self._parent.style['tickTextOffset'][1]
         path = QtGui.QPainterPath()
         h, w = self.rect.height(), self.rect.width()
-        # middle = (w + self._y_margin)/2
-        # middle = (w + self._x_margin)/2
         middle = w/2 - 0.5
-        # aw = (h + self._x_margin)/2
         aw = h/2
         left = middle - aw
         right = middle + aw
@@ -341,6 +363,8 @@ class XAxisLabel(AxisLabel):
         path.lineTo(right, 0)
         path.closeSubpath()
         self.path = path
+
+        # top left point is local origin and tip of the arrow path
         self.tl = QtCore.QPointF(0, -y_offset)
 
 
@@ -364,15 +388,18 @@ class YAxisLabel(AxisLabel):
         super().__init__(*args, **kwargs)
 
         self._chart = chart
+
         chart.sigRangeChanged.connect(self.update_on_resize)
+
         self._last_datum = (None, None)
 
         # pull text offset from axis from parent axis
-        self.x_offset = self.parent.style['tickTextOffset'][0]
+        if getattr(self._parent, 'txt_offsets', False):
+            self.x_offset, y_offset = self._parent.txt_offsets()
 
     def size_hint(self) -> Tuple[float, float]:
         # size to parent axis width
-        return None, self.parent.width()
+        return None, self._parent.width()
 
     def update_label(
         self,
@@ -392,6 +419,7 @@ class YAxisLabel(AxisLabel):
 
         br = self.boundingRect()
         h = br.height()
+
         self.setPos(QPointF(
             x_offset,
             abs_pos.y() - h / 2 - self._y_margin / 2
@@ -411,6 +439,10 @@ class YAxisLabel(AxisLabel):
         index: int,
         value: float,
     ) -> None:
+        """Update the label's text contents **and** position from
+        a view box coordinate datum.
+
+        """
         self._last_datum = (index, value)
         self.update_label(
             self._chart.mapFromView(QPointF(index, value)),
@@ -418,7 +450,7 @@ class YAxisLabel(AxisLabel):
         )
 
     def _draw_arrow_path(self):
-        x_offset = self.parent.style['tickTextOffset'][0]
+        x_offset = self._parent.style['tickTextOffset'][0]
         path = QtGui.QPainterPath()
         h = self.rect.height()
         path.moveTo(0, 0)