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bec_widgets/bec_widgets/utils/busy_loader.py

254 lines
7.8 KiB
Python

from __future__ import annotations
from qtpy.QtCore import QEvent, QObject, Qt, QTimer
from qtpy.QtGui import QColor, QFont
from qtpy.QtWidgets import (
QApplication,
QFrame,
QHBoxLayout,
QLabel,
QMainWindow,
QPushButton,
QVBoxLayout,
QWidget,
)
from bec_widgets import BECWidget
from bec_widgets.utils.colors import apply_theme
from bec_widgets.widgets.plots.waveform.waveform import Waveform
from bec_widgets.widgets.utility.spinner.spinner import SpinnerWidget
class _OverlayEventFilter(QObject):
"""Keeps the overlay sized and stacked over its target widget."""
def __init__(self, target: QWidget, overlay: QWidget):
super().__init__(target)
self._target = target
self._overlay = overlay
def eventFilter(self, obj, event):
if obj is self._target and event.type() in (
QEvent.Resize,
QEvent.Show,
QEvent.LayoutRequest,
QEvent.Move,
):
self._overlay.setGeometry(self._target.rect())
self._overlay.raise_()
return False
class BusyLoaderOverlay(QWidget):
"""
A semi-transparent scrim with centered text and an animated spinner.
Call show()/hide() directly, or use via `install_busy_loader(...)`.
Args:
parent(QWidget): The parent widget to overlay.
text(str): Initial text to display.
opacity(float): Overlay opacity (0..1).
Returns:
BusyLoaderOverlay: The overlay instance.
"""
def __init__(self, parent: QWidget, text: str = "Loading…", opacity: float = 0.85, **kwargs):
super().__init__(parent=parent, **kwargs)
self.setAttribute(Qt.WA_StyledBackground, True)
self.setAutoFillBackground(False)
self.setAttribute(Qt.WA_TranslucentBackground, True)
self._opacity = opacity
self._label = QLabel(text, self)
self._label.setAlignment(Qt.AlignHCenter | Qt.AlignVCenter)
f = QFont(self._label.font())
f.setBold(True)
f.setPointSize(f.pointSize() + 1)
self._label.setFont(f)
self._spinner = SpinnerWidget(self)
self._spinner.setFixedSize(42, 42)
lay = QVBoxLayout(self)
lay.setContentsMargins(24, 24, 24, 24)
lay.setSpacing(10)
lay.addStretch(1)
lay.addWidget(self._spinner, 0, Qt.AlignHCenter)
lay.addWidget(self._label, 0, Qt.AlignHCenter)
lay.addStretch(1)
self._frame = QFrame(self)
self._frame.setObjectName("busyFrame")
self._frame.setAttribute(Qt.WA_TransparentForMouseEvents, True)
self._frame.lower()
# Defaults
self._scrim_color = QColor(0, 0, 0, 110)
self._label_color = QColor(240, 240, 240)
self.update_palette()
# Start hidden; interactions beneath are blocked while visible
self.hide()
# --- API ---
def set_text(self, text: str):
"""
Update the overlay text.
Args:
text(str): The text to display on the overlay.
"""
self._label.setText(text)
def set_opacity(self, opacity: float):
"""
Set overlay opacity (0..1).
Args:
opacity(float): The opacity value between 0.0 (fully transparent) and 1.0 (fully opaque).
"""
self._opacity = max(0.0, min(1.0, float(opacity)))
# Re-apply alpha using the current theme color
if isinstance(self._scrim_color, QColor):
base = QColor(self._scrim_color)
base.setAlpha(int(255 * self._opacity))
self._scrim_color = base
self.update()
def update_palette(self):
"""
Update colors from the current application theme.
"""
app = QApplication.instance()
if hasattr(app, "theme"):
theme = app.theme # type: ignore[attr-defined]
self._bg = theme.color("BORDER")
self._fg = theme.color("FG")
self._primary = theme.color("PRIMARY")
else:
# Fallback neutrals
self._bg = QColor(30, 30, 30)
self._fg = QColor(230, 230, 230)
# Semi-transparent scrim derived from bg
self._scrim_color = QColor(self._bg)
self._scrim_color.setAlpha(int(255 * max(0.0, min(1.0, getattr(self, "_opacity", 0.35)))))
self._spinner.update()
fg_hex = self._fg.name() if isinstance(self._fg, QColor) else str(self._fg)
self._label.setStyleSheet(f"color: {fg_hex};")
self._frame.setStyleSheet(
f"#busyFrame {{ border: 2px dashed {fg_hex}; border-radius: 9px; background-color: rgba(128, 128, 128, 110); }}"
)
self.update()
# --- QWidget overrides ---
def showEvent(self, e):
self._spinner.start()
super().showEvent(e)
def hideEvent(self, e):
self._spinner.stop()
super().hideEvent(e)
def resizeEvent(self, e):
super().resizeEvent(e)
r = self.rect().adjusted(10, 10, -10, -10)
self._frame.setGeometry(r)
def paintEvent(self, e):
super().paintEvent(e)
def install_busy_loader(
target: QWidget, text: str = "Loading…", start_loading: bool = False, opacity: float = 0.35
) -> BusyLoaderOverlay:
"""
Attach a BusyLoaderOverlay to `target` and keep it sized and stacked.
Args:
target(QWidget): The widget to overlay.
text(str): Initial text to display.
start_loading(bool): If True, show the overlay immediately.
opacity(float): Overlay opacity (0..1).
Returns:
BusyLoaderOverlay: The overlay instance.
"""
overlay = BusyLoaderOverlay(target, text=text, opacity=opacity)
overlay.setGeometry(target.rect())
filt = _OverlayEventFilter(target, overlay)
overlay._filter = filt # type: ignore[attr-defined]
target.installEventFilter(filt)
if start_loading:
overlay.show()
return overlay
# --------------------------
# Launchable demo
# --------------------------
class DemoWidget(BECWidget, QWidget): # pragma: no cover
def __init__(self, parent=None):
super().__init__(
parent=parent, theme_update=True, start_busy=True, busy_text="Demo: Initializing…"
)
self._title = QLabel("Demo Content", self)
self._title.setAlignment(Qt.AlignCenter)
self._title.setFrameStyle(QFrame.Panel | QFrame.Sunken)
lay = QVBoxLayout(self)
lay.addWidget(self._title)
waveform = Waveform(self)
waveform.plot([1, 2, 3, 4, 5])
lay.addWidget(waveform, 1)
QTimer.singleShot(5000, self._ready)
def _ready(self):
self._title.setText("Ready ✓")
self.set_busy(False)
class DemoWindow(QMainWindow):
def __init__(self):
super().__init__()
self.setWindowTitle("Busy Loader — BECWidget demo")
left = DemoWidget()
right = DemoWidget()
btn_on = QPushButton("Right → Loading")
btn_off = QPushButton("Right → Ready")
btn_text = QPushButton("Set custom text")
btn_on.clicked.connect(lambda: right.set_busy(True, "Fetching data…"))
btn_off.clicked.connect(lambda: right.set_busy(False))
btn_text.clicked.connect(lambda: right.set_busy_text("Almost there…"))
panel = QWidget()
prow = QVBoxLayout(panel)
prow.addWidget(btn_on)
prow.addWidget(btn_off)
prow.addWidget(btn_text)
prow.addStretch(1)
central = QWidget()
row = QHBoxLayout(central)
row.setContentsMargins(12, 12, 12, 12)
row.setSpacing(12)
row.addWidget(left, 1)
row.addWidget(right, 1)
row.addWidget(panel, 0)
self.setCentralWidget(central)
self.resize(900, 420)
if __name__ == "__main__": # pragma: no cover
import sys
app = QApplication(sys.argv)
apply_theme("light")
w = DemoWindow()
w.show()
sys.exit(app.exec())