replace ScaledScrollBar with BigScrollBar

step 1 - manually moving the slider

src/ui/bigtext/BigScrollBar.py

@@ -0,0 +1,173 @@
+from PySide6.QtWidgets import QWidget, QStylePainter, QStyle, QStyleOptionSlider, QSlider
+from PySide6.QtCore import Qt, QSize, QEvent, QRect, QPoint, Signal
+
+
+class BigScrollBar(QWidget):
+    value_changed = Signal(str)
+    """Signal emitted when the range slider value changes. 
+        **Note**: The value is a string and must be parsed into an int. 
+        QT's signal api only supports 32bit integers. Ints larger 
+        than 2**32-1 will overflow. Probably because there is some C/C++
+        code involved. We work around this by converting the python int 
+        into a string."""
+
+    pressedControl = QStyle.SubControl.SC_None
+    click_offset = 0
+
+    scale = 10000
+
+    minimun = 0
+    value = 0
+    maximum = 100
+
+    def __init__(self):
+        super(BigScrollBar, self).__init__()
+
+    def setMinimum(self, min: int):
+        self.minimun = min
+        if self.value < self.minimun:
+            self.set_value(self.minimun)
+
+    def setMaximum(self, max: int):
+        self.maximum = max
+        if self.value > self.maximum:
+            self.set_value(self.maximum)
+
+    def paintEvent(self, event):
+        p = QStylePainter(self)
+        o = self.style_options()
+        print(f"style_options: sliderPosition: {o.sliderPosition}")
+        p.drawComplexControl(QStyle.ComplexControl.CC_ScrollBar, o)
+
+    def style_options(self) -> QStyleOptionSlider:
+        o = QStyleOptionSlider()
+        o.initFrom(self)
+        o.orientation = Qt.Orientation.Vertical
+        o.subControls = QStyle.SubControl.SC_All
+
+        if self.pressedControl != QStyle.SubControl.SC_None:
+            o.activeSubControls = self.pressedControl  # QStyle.SubControl.SC_None
+            o.state = o.state | QStyle.StateFlag.State_Sunken
+
+        o.singleStep = 1
+
+        # scale values to 10000
+
+        t = self.scale / self.maximum
+        o.minimum = self.minimun * t
+        o.maximum = self.maximum * t
+        o.sliderPosition = int(self.value * t)
+        print(f"t={t}")
+        print(f"({self.minimun}, {self.value}, {self.maximum}) -> ({o.minimum},{o.sliderPosition},{o.maximum})")
+
+        return o
+
+    ## QSize QScrollBar::sizeHint() const
+    # {
+    #    ensurePolished();
+    #    QStyleOptionSlider opt;
+    #    initStyleOption(&opt);
+
+    #    int scrollBarExtent = style()->pixelMetric(QStyle::PM_ScrollBarExtent, &opt, this);
+    #    int scrollBarSliderMin = style()->pixelMetric(QStyle::PM_ScrollBarSliderMin, &opt, this);
+    #    QSize size;
+    #    if (opt.orientation == Qt::Horizontal)
+    #        size = QSize(scrollBarExtent * 2 + scrollBarSliderMin, scrollBarExtent);
+    #    else
+    #        size = QSize(scrollBarExtent, scrollBarExtent * 2 + scrollBarSliderMin);
+    #
+    #   return style()->sizeFromContents(QStyle::CT_ScrollBar, &opt, size, this);
+    # }
+
+    def sizeHint(self):
+        scroll_bar_extend = self.style().pixelMetric(QStyle.PixelMetric.PM_ScrollBarExtent)
+        scroll_bar_slider_min = self.style().pixelMetric(QStyle.PixelMetric.PM_ScrollBarSliderMin)
+        # print(f"scroll_bar_extend: {scroll_bar_extend}, scroll_bar_slider_min: {scroll_bar_slider_min}")
+        # for vertial
+        size = QSize(scroll_bar_extend, scroll_bar_extend * 2 + scroll_bar_slider_min)
+
+        o = self.style_options()
+        return self.style().sizeFromContents(QStyle.ContentsType.CT_ScrollBar, o, size, self)
+
+    def event(self, event: QEvent) -> bool:
+        # print(f"event type: {event.type()}")
+
+        if event.type() == QEvent.Type.MouseButtonPress:
+            pass
+            # print(f"mouse button pressed")
+
+        return super().event(event)
+
+    def mousePressEvent(self, event):
+        style_options = self.style_options()
+        style_options.keyboardModifiers = event.modifiers()  ## not sure why, copied from https://github.com/qt/qtbase/blob/dev/src/widgets/widgets/qscrollbar.cpp#L535
+
+        self.pressedControl = self.style().hitTestComplexControl(QStyle.ComplexControl.CC_ScrollBar, style_options,
+                                                                 event.position().toPoint(), self)
+        # print(f"pressedControl {self.pressedControl}")
+
+        sr: QRect = self.style().subControlRect(QStyle.ComplexControl.CC_ScrollBar, style_options,
+                                                QStyle.SubControl.SC_ScrollBarSlider, self)
+        click: QPoint = event.position().toPoint()
+        pressYValue = click.y() - sr.center().y() + sr.topLeft().y()
+        pressYValue = self.pixelPosToRangeValue(pressYValue)
+        # print(f"pressYValue {pressYValue}")
+
+        if self.pressedControl == QStyle.SubControl.SC_ScrollBarSlider:
+            self.click_offset = click.y() - sr.y()
+
+        # todo
+        if (self.pressedControl == QStyle.SubControl.SC_ScrollBarAddPage
+            or self.pressedControl == QStyle.SubControl.SC_ScrollBarSubPage) \
+                and event.button() == Qt.MouseButton.MiddleButton:
+            slider_length = sr.height()
+            self.set_value(self.pixelPosToRangeValue(event.position().toPoint().y()))
+            self.pressedControl = QStyle.SubControl.SC_ScrollBarSlider
+            self.click_offset = slider_length / 2
+            pass
+
+    def mouseReleaseEvent(self, event):
+        self.pressedControl = QStyle.SubControl.SC_None
+
+    def mouseMoveEvent(self, event):
+        if self.pressedControl == QStyle.SubControl.SC_None:
+            return
+
+        if self.pressedControl == QStyle.SubControl.SC_ScrollBarSlider:
+            click: QPoint = event.position().toPoint()
+            new_position = self.pixelPosToRangeValue(click.y() - self.click_offset)
+            m = self.style().pixelMetric(QStyle.PixelMetric.PM_MaximumDragDistance, self.style_options(), self)
+            if m >= 0:
+                r: QRect = self.rect()
+                r.adjust(-m, -m, m, m)
+                if not r.contains(event.position().toPoint()):
+                    new_position = self.snap_back_position
+
+            # print(f"move to value: {new_position}")
+            self.set_value(new_position)
+
+    def pixelPosToRangeValue(self, pos: int):
+        opt: QStyleOptionSlider = self.style_options()
+
+        gr: QRect = self.style().subControlRect(QStyle.ComplexControl.CC_ScrollBar, opt,
+                                                QStyle.SubControl.SC_ScrollBarGroove, self)
+        sr: QRect = self.style().subControlRect(QStyle.ComplexControl.CC_ScrollBar, opt,
+                                                QStyle.SubControl.SC_ScrollBarSlider, self)
+
+        # only for vertical scrollbars
+        sliderLength = sr.height();
+        sliderMin = gr.y();
+        sliderMax = gr.bottom() - sliderLength + 1;
+
+        val = QStyle.sliderValueFromPosition(opt.minimum, opt.maximum, pos - sliderMin,
+                                             sliderMax - sliderMin, opt.upsideDown)
+
+        t = self.scale / self.maximum
+        val = int(val / t)
+        # print(f"pixelPosToRangeValue({pos}) -> {val}")
+        return val
+
+    def set_value(self, value: int):
+        self.value = value
+        self.value_changed.emit(str(value))
+        self.repaint()

src/ui/bigtext/bigtext.py

@@ -11,6 +11,7 @@ from PySide6.QtGui import QMouseEvent
 from PySide6.QtWidgets import *
 
 from src.ui.ScaledScrollBar import ScaledScrollBar
+from src.ui.bigtext.BigScrollBar import BigScrollBar
 from src.ui.bigtext.highlight_regex import HighlightRegex
 from src.ui.bigtext.highlight_selection import HighlightSelection
 from src.ui.bigtext.highlighted_range import HighlightedRange
@@ -86,7 +87,7 @@ class BigText(QWidget):
         self.grid.setVerticalSpacing(0)
         self.setLayout(self.grid)
 
-        self.v_scroll_bar = ScaledScrollBar()
+        self.v_scroll_bar = BigScrollBar()
 
         self.big_text = InnerBigText(self, model, self.v_scroll_bar)
         self.big_text.setSizePolicy(QSizePolicy(QSizePolicy.Policy.Expanding, QSizePolicy.Policy.Expanding))
@@ -97,7 +98,7 @@ class BigText(QWidget):
         self.h_scroll_bar.valueChanged.connect(self.big_text.h_scroll_event)
 
         # self.v_scroll_bar.setPageStep(1)
-        self.v_scroll_bar.scaledValueChanged.connect(self.big_text.v_scroll_event)
+        self.v_scroll_bar.value_changed.connect(self.big_text.v_scroll_event)
 
         if show_range_slider:
             self.range_limit = RangeSlider()
@@ -308,12 +309,12 @@ class InnerBigText(QWidget):
     def scroll_by_lines(self, scroll_lines: int):
         self.scroll_lines = scroll_lines
         self.update()
-        self.parent.v_scroll_bar.setValue(self._byte_offset)
+        self.parent.v_scroll_bar.set_value(self._byte_offset)
 
     def scroll_to_byte(self, byte_offset: int):
         self._byte_offset = min(byte_offset, self.model.byte_count())
         self.update()
-        self.parent.v_scroll_bar.setValue(self._byte_offset)
+        self.parent.v_scroll_bar.set_value(self._byte_offset)
 
     # noinspection PyTypeChecker
     def mousePressEvent(self, e: QtGui.QMouseEvent) -> None: