[FIX] Heatmap: Sticky footer

Orange/widgets/utils/stickygraphicsview.py

@@ -1,8 +1,10 @@
 import sys
 import math
 
-from PyQt5.QtCore import Qt, QRectF, QEvent, QCoreApplication, QObject, QPointF
-from PyQt5.QtGui import QBrush, QPalette, QTransform
+from PyQt5.QtCore import (
+    Qt, QRectF, QEvent, QCoreApplication, QObject, QPointF, QRect
+)
+from PyQt5.QtGui import QBrush, QPalette, QTransform, QPolygonF
 from PyQt5.QtWidgets import (
     QGraphicsView, QGraphicsScene, QWidget, QVBoxLayout, QSizePolicy,
     QScrollBar, QGraphicsDropShadowEffect
@@ -109,7 +111,7 @@ def setFooterSceneRect(self, rect: QRectF) -> None:
             self.__updateFooter()
 
     def footerSceneRect(self) -> QRectF:
-        return QRectF(self.__headerRect)
+        return QRectF(self.__footerRect)
 
     def setScene(self, scene: QGraphicsScene) -> None:
         """Reimplemented"""
@@ -218,10 +220,11 @@ def __updateView(self, view: QGraphicsView, rect: QRectF) -> None:
             container.setVisible(False)
             return
         # map the rect to (main) viewport coordinates
-        viewrect = self.mapFromScene(rect).boundingRect()
+        viewrect = qgraphicsview_map_rect_from_scene(self, rect).boundingRect()
+        viewrect = qrectf_to_inscribed_rect(viewrect)
         viewportrect = self.viewport().rect()
-        visible = not (viewrect.top() >= viewportrect.top()
-                       and viewrect.bottom() <= viewportrect.bottom())
+        visible = (viewrect.top() < viewportrect.top() or
+                   viewrect.y() + viewrect.height() > viewportrect.y() + viewportrect.height())
         container.setVisible(visible)
         # force immediate layout of the container overlay
         QCoreApplication.sendEvent(container, QEvent(QEvent.LayoutRequest))
@@ -248,6 +251,32 @@ def viewportEvent(self, event: QEvent) -> bool:
         return super().viewportEvent(event)
 
 
+def qgraphicsview_map_rect_from_scene(
+        view: QGraphicsView, rect: QRectF
+) -> QPolygonF:
+    """Like QGraphicsView.mapFromScene(QRectF) but returning a QPolygonF
+    (without rounding).
+    """
+    tr = view.viewportTransform()
+    p1 = tr.map(rect.topLeft())
+    p2 = tr.map(rect.topRight())
+    p3 = tr.map(rect.bottomRight())
+    p4 = tr.map(rect.bottomLeft())
+    return QPolygonF([p1, p2, p3, p4])
+
+
+def qrectf_to_inscribed_rect(rect: QRectF) -> QRect:
+    """
+    Return the largest integer QRect such that it is completely contained in
+    `rect`.
+    """
+    xmin = int(math.ceil(rect.x()))
+    xmax = int(math.floor(rect.right()))
+    ymin = int(math.ceil(rect.top()))
+    ymax = int(math.floor(rect.bottom()))
+    return QRect(xmin, ymin, max(xmax - xmin, 0), max(ymax - ymin, 0))
+
+
 def main(args):  # pragma: no cover
     # pylint: disable=import-outside-toplevel,protected-access
     from PyQt5.QtWidgets import QApplication, QAction

Orange/widgets/utils/tests/test_stickygraphicsview.py

@@ -1,18 +1,23 @@
 from PyQt5.QtCore import Qt, QRectF, QPoint, QPointF
 from PyQt5.QtGui import QBrush, QWheelEvent
-from PyQt5.QtWidgets import QGraphicsScene, QWidget, QApplication
+from PyQt5.QtWidgets import QGraphicsScene, QWidget, QApplication, QStyle
 
 from Orange.widgets.tests.base import GuiTest
 
 from Orange.widgets.utils.stickygraphicsview import StickyGraphicsView
 
 
 class TestStickyGraphicsView(GuiTest):
-    def test(self):
+    def create_view(self):
         view = StickyGraphicsView()
         scene = QGraphicsScene(view)
-        scene.setBackgroundBrush(QBrush(Qt.lightGray, Qt.CrossPattern))
         view.setScene(scene)
+        return view
+
+    def test(self):
+        view = self.create_view()
+        scene = view.scene()
+        scene.setBackgroundBrush(QBrush(Qt.lightGray, Qt.CrossPattern))
         scene.addRect(
             QRectF(0, 0, 300, 20), Qt.red, QBrush(Qt.red, Qt.BDiagPattern))
         scene.addRect(QRectF(0, 25, 300, 100))
@@ -48,6 +53,66 @@ def test(self):
 
         qWheelScroll(header.viewport(), angleDelta=QPoint(0, -720 * 8))
 
+    @staticmethod
+    def _ensure_laid_out(view: QWidget) -> None:
+        """Ensure view has had pending resize events flushed."""
+        # when a widget is not visible it does not get resizeEvents dispatched
+        # immediately, only before it is actually shown or its rendering is
+        # requested.
+        view.grab()
+
+    def _test_visibility(self, view: StickyGraphicsView) -> None:
+        header = view.headerView()
+        footer = view.footerView()
+        vsbar = view.verticalScrollBar()
+        vsbar.triggerAction(vsbar.SliderToMinimum)
+        self._ensure_laid_out(view)
+
+        self.assertFalse(header.isVisibleTo(view))
+        self.assertTrue(footer.isVisibleTo(view))
+
+        vsbar.triggerAction(vsbar.SliderSingleStepAdd)
+        self._ensure_laid_out(view)
+
+        self.assertTrue(header.isVisibleTo(view))
+        self.assertTrue(footer.isVisibleTo(view))
+
+        vsbar.triggerAction(vsbar.SliderToMaximum)
+        self._ensure_laid_out(view)
+
+        self.assertTrue(header.isVisibleTo(view))
+        self.assertFalse(footer.isVisibleTo(view))
+
+        vsbar.triggerAction(vsbar.SliderSingleStepSub)
+        self._ensure_laid_out(view)
+        if not view.style().styleHint(QStyle.SH_ScrollBar_Transient, None, vsbar):
+            # cannot reliably test due to QTBUG-65074
+            self.assertTrue(header.isVisibleTo(view))
+            self.assertTrue(footer.isVisibleTo(view))
+
+    def test_fractional_1(self):
+        view = self.create_view()
+        view.resize(300, 100)
+        scenerect = QRectF(-0.1, -0.1, 300.2, 300.2)
+        headerrect = QRectF(-0.1, -0.1, 300.2, 20.2)
+        footerrect = QRectF(-0.1, 279.9, 300.2, 20.2)
+        view.setSceneRect(scenerect)
+        view.setHeaderSceneRect(headerrect)
+        view.setFooterSceneRect(footerrect)
+        self._test_visibility(view)
+
+    def test_fractional_2(self):
+        view = self.create_view()
+        view.resize(300, 100)
+        view.grab()
+        scenerect = QRectF(0.1, 0.1, 300, 299.8)
+        headerrect = QRectF(0.1, 0.1, 300, 20)
+        footerrect = QRectF(0.1, 299.9 - 20, 300, 20)
+        view.setSceneRect(scenerect)
+        view.setHeaderSceneRect(headerrect)
+        view.setFooterSceneRect(footerrect)
+        self._test_visibility(view)
+
 
 def qWheelScroll(
         widget: QWidget, buttons=Qt.NoButton, modifiers=Qt.NoModifier,