v0.47.0: no album art shows a debossed panel, not a flat square

The sidebar's art square, when a track has no art, is now the list's own
background with a rounded panel set into it, debossed like the visualizer
and the now-playing panel. paint_deboss takes its rims in pixels when
asked, so a panel as tall as the sidebar is recessed as much as a short
one rather than fading over 16 px.

lintunes/__init__.py

@@ -1,3 +1,3 @@
 """LinTunes — iTunes-style music library manager and player for Linux."""
 
-__version__ = "0.46.0"
+__version__ = "0.47.0"

lintunes/gui/sidebar.py

@@ -4,7 +4,7 @@ from PyQt6.QtWidgets import (
     QHBoxLayout, QListWidget, QListWidgetItem, QStackedWidget, QSizePolicy,
     QFrame,
 )
-from PyQt6.QtCore import Qt, QTimer, QPoint, pyqtSignal
+from PyQt6.QtCore import Qt, QTimer, QPoint, QRectF, pyqtSignal
 from PyQt6.QtGui import QBrush, QPainter, QPalette, QPixmap
 
 from lintunes.models import PlaylistType
@@ -253,9 +253,14 @@ class FriendPlaylistList(QListWidget):
             self.playlist_selected.emit(current.data(Qt.ItemDataRole.UserRole))
 
 
+# The no-art panel: inset from the list's edges, corners like the visualizer's.
+NO_ART_MARGIN = 6
+NO_ART_RADIUS = 8
+
+
 class SidebarArt(QWidget):
-    """Square album art pinned to the sidebar bottom; gray square when the
-    current track has no embedded art. A click opens the big art window, or,
+    """Square album art pinned to the sidebar bottom; an empty debossed panel
+    when the current track has no embedded art. A click opens the big art window, or,
     on the gray square, asks for the track's art to be downloaded."""
 
     download_art_requested = pyqtSignal(int)  # track id
@@ -317,10 +322,18 @@ class SidebarArt(QWidget):
 
     def paintEvent(self, event):
         painter = QPainter(self)
-        # A shade lighter than mid: the sidebar group's frame line is drawn
-        # in mid, and would vanish into a placeholder of the same gray.
-        painter.fillRect(self.rect(), self.palette().mid().color().lighter(112))
         if self._pixmap is None or self._pixmap.isNull():
+            # No art: the list's own background, and in it a rounded panel
+            # debossed like the visualizer and the now-playing panel.
+            painter.fillRect(self.rect(), self.palette().base())
+            painter.setRenderHint(QPainter.RenderHint.Antialiasing)
+            rect = QRectF(self.rect()).adjusted(
+                NO_ART_MARGIN + 0.5, NO_ART_MARGIN + 0.5,
+                -NO_ART_MARGIN - 0.5, -NO_ART_MARGIN - 0.5)
+            theme.paint_deboss(painter, rect,
+                               self.palette().alternateBase().color(),
+                               NO_ART_RADIUS,
+                               rim=theme.button_rim_px(self.fontMetrics()))
             return
         scaled = self._pixmap.scaled(
             self.size(), Qt.AspectRatioMode.KeepAspectRatioByExpanding,

lintunes/theme.py

@@ -235,17 +235,14 @@ def deboss_qss(selector: str, color: QColor, *, radius: int = 8,
             f" background: {emboss_gradient(color, pressed=True)}; {extra} }}")
 
 
-def paint_deboss(painter, rect, color: QColor, radius: float):
+def paint_deboss(painter, rect, color: QColor, radius: float,
+                 rim: float | None = None):
     """``deboss_qss`` for a widget that paints itself: fills ``rect`` (a
-    QRectF) as a debossed rounded panel and returns its path, for clipping."""
-    from PyQt6.QtCore import QPointF
-    from PyQt6.QtGui import QLinearGradient, QPainterPath, QPen
-    path = QPainterPath()
-    path.addRoundedRect(rect, radius, radius)
-    gradient = QLinearGradient(QPointF(0, rect.top()), QPointF(0, rect.bottom()))
-    for pos, stop in emboss_stops(color, pressed=True):
-        gradient.setColorAt(pos, stop)
-    painter.fillPath(path, gradient)
+    QRectF) as a debossed rounded panel and returns its path, for clipping.
+    ``rim`` (pixels) fixes the rims' height for a panel much taller than a
+    button; without it they're ``EMBOSS_RIM_WIDTH`` of the height."""
+    from PyQt6.QtGui import QPen
+    path = _fill_embossed(painter, rect, color, radius, rim, pressed=True)
     painter.setPen(QPen(color.darker(135), 1))
     painter.drawPath(path)
     # the darker top edge
@@ -257,6 +254,25 @@ def paint_deboss(painter, rect, color: QColor, radius: float):
     return path
 
 
+def _fill_embossed(painter, rect, color: QColor, radius: float,
+                   rim: float | None, pressed: bool):
+    """Fill a rounded ``rect`` with ``emboss_stops``; ``rim`` in pixels, or
+    None for the stops' own fractions. Returns the path."""
+    from PyQt6.QtCore import QPointF
+    from PyQt6.QtGui import QLinearGradient, QPainterPath
+    path = QPainterPath()
+    path.addRoundedRect(rect, radius, radius)
+    stops = emboss_stops(color, pressed)
+    if rim is not None:
+        edge = min(rim / max(rect.height(), 1.0), 0.49)
+        stops = [(pos, c) for pos, (_, c) in zip([0, edge, 0.5, 1 - edge, 1], stops)]
+    gradient = QLinearGradient(QPointF(0, rect.top()), QPointF(0, rect.bottom()))
+    for pos, stop in stops:
+        gradient.setColorAt(pos, stop)
+    painter.fillPath(path, gradient)
+    return path
+
+
 def button_rim_px(metrics) -> float:
     """How tall a button's rims are, in pixels, for a font with these
     QFontMetrics: ``EMBOSS_RIM_WIDTH`` of a button's height, which is the
@@ -269,18 +285,8 @@ def paint_emboss(painter, rect, color: QColor, radius: float, rim: float):
     """A button's face for a widget that paints itself: ``emboss_stops`` lit
     from above, but with rims ``rim`` pixels tall whatever ``rect``'s height,
     so a long scrollbar thumb is embossed exactly as much as a button."""
-    from PyQt6.QtCore import QPointF
-    from PyQt6.QtGui import QLinearGradient, QPainterPath, QPen
-    path = QPainterPath()
-    path.addRoundedRect(rect, radius, radius)
-    height = max(rect.height(), 1.0)
-    edge = min(rim / height, 0.49)
-    stops = emboss_stops(color)
-    positions = [0, edge, 0.5, 1 - edge, 1]
-    gradient = QLinearGradient(QPointF(0, rect.top()), QPointF(0, rect.bottom()))
-    for pos, (_, stop) in zip(positions, stops):
-        gradient.setColorAt(pos, stop)
-    painter.fillPath(path, gradient)
+    from PyQt6.QtGui import QPen
+    path = _fill_embossed(painter, rect, color, radius, rim, pressed=False)
     painter.setPen(QPen(color.darker(135), 1))
     painter.drawPath(path)
     # the darker bottom edge (emboss_edges)

tests/test_round80.py

@@ -98,3 +98,46 @@ def test_thumb_paints(qapp):
     trough = image.pixelColor(7, 5)
     middle = image.pixelColor(7, thumb.center().y())
     assert middle != trough
+
+
+# --------------------------------------------------------------------------
+# no album art: a debossed panel, not a flat square
+# --------------------------------------------------------------------------
+
+def test_no_art_is_a_debossed_panel(qapp):
+    from PyQt6.QtCore import QObject, pyqtSignal
+    from lintunes.gui.sidebar import NO_ART_MARGIN, SidebarArt
+
+    class Player(QObject):
+        track_changed = pyqtSignal(object)
+
+    art = SidebarArt(Player())
+    art.resize(200, 200)
+    image = art.grab().toImage()
+    base = art.palette().base().color()
+    # the margin around the panel is the list's own background...
+    assert image.pixelColor(1, 100) == base
+    # ...the corner is rounded off, so it's background too...
+    assert image.pixelColor(NO_ART_MARGIN + 1, NO_ART_MARGIN + 1) == base
+    # ...and the panel is shaded darker at the top than in the middle
+    top = image.pixelColor(100, NO_ART_MARGIN + 2).lightness()
+    middle = image.pixelColor(100, 100).lightness()
+    assert top < middle
+
+
+def test_deboss_rims_can_be_fixed_in_pixels(qapp):
+    """On a 400 px panel the default rims are 32 px deep; 3 px rims leave
+    row 10 already on the face, a good deal lighter."""
+    from PyQt6.QtCore import QRectF
+    from PyQt6.QtGui import QImage, QPainter
+    color = QColor("#e0e0e0")
+
+    def row10(**kw):
+        image = QImage(100, 400, QImage.Format.Format_ARGB32)
+        image.fill(0)
+        painter = QPainter(image)
+        theme.paint_deboss(painter, QRectF(0.5, 0.5, 99, 399), color, 8, **kw)
+        painter.end()
+        return image.pixelColor(50, 10).lightness()
+
+    assert row10(rim=3) > row10() + 5