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QCustomQSlider

QCustomQSlider is an enhanced QSlider widget that provides improved click-to-set functionality, allowing users to click anywhere on the slider track to instantly set the slider value to that position.

Overview​

  • Enhanced Interaction:
    Click anywhere on the slider track to instantly set the slider value.

  • Precise Value Setting:
    Accurate position-to-value conversion using Qt's style system.

  • Orientation Support:
    Works with both horizontal and vertical slider orientations.

  • Native Integration:
    Maintains all standard QSlider functionality and styling.

Constructor​

QCustomQSlider(parent=None)
  • parent:
    The parent widget (defaults to None).

Key Features​

Click-to-Set Functionality​

  • Standard QSlider: Requires dragging the handle to change values
  • QCustomQSlider: Click anywhere on track for instant value setting
  • Precision: Accurate value calculation based on click position

Orientation Support​

  • Horizontal Sliders: Left-to-right value progression
  • Vertical Sliders: Bottom-to-top value progression (standard Qt behavior)

Native Behavior Preservation​

  • Maintains all original QSlider signals and properties
  • Compatible with existing QSlider styling and theming
  • No breaking changes to existing functionality

Methods​

mousePressEvent(event)​

  • Description:
    Overrides the mouse press event to enable click-to-set functionality.

  • Behavior:

    • Detects left mouse button clicks
    • Calculates value based on click position
    • Sets slider value instantly
    • Calls parent implementation for other button handling

pixelPosToRangeValue(pos)​

  • Description:
    Converts mouse click position to slider value.

  • Parameters:

    • pos: QPoint representing click position

  • Returns:
    Integer value within slider's min-max range

  • Process:

    1. Creates style options for slider
    2. Calculates slider groove and handle dimensions
    3. Converts pixel position to value using Qt's style system
    4. Handles both horizontal and vertical orientations

Usage Example​

Basic Implementation​

from qtpy.QtWidgets import QApplication, QVBoxLayout, QWidget, QLabel
from Custom_Widgets.QCustomQSlider import QCustomQSlider

app = QApplication([])

# Create main window
window = QWidget()
layout = QVBoxLayout(window)

# Create custom slider
slider = QCustomQSlider()
slider.setOrientation(Qt.Horizontal)
slider.setMinimum(0)
slider.setMaximum(100)
slider.setValue(50)

# Create value display label
value_label = QLabel("Value: 50")

# Connect value change signal
def on_value_changed(value):
    value_label.setText(f"Value: {value}")

slider.valueChanged.connect(on_value_changed)

layout.addWidget(slider)
layout.addWidget(value_label)
window.show()

app.exec_()

Vertical Slider Example​

# Create vertical slider
vertical_slider = QCustomQSlider()
vertical_slider.setOrientation(Qt.Vertical)
vertical_slider.setMinimum(0)
vertical_slider.setMaximum(100)
vertical_slider.setValue(25)

# Vertical sliders work with the same click-to-set functionality

Styled Slider with Custom Range​

class VolumeControl(QWidget):
    def __init__(self):
        super().__init__()
        
        self.slider = QCustomQSlider()
        self.slider.setOrientation(Qt.Horizontal)
        self.slider.setMinimum(0)
        self.slider.setMaximum(100)
        self.slider.setValue(75)
        
        # Custom styling
        self.slider.setStyleSheet("""
            QSlider::groove:horizontal {
                border: 1px solid #999999;
                height: 8px;
                background: qlineargradient(x1:0, y1:0, x2:0, y2:1, 
                    stop:0 #B1B1B1, stop:1 #c4c4c4);
                margin: 2px 0;
            }
            
            QSlider::handle:horizontal {
                background: qlineargradient(x1:0, y1:0, x2:1, y2:1, 
                    stop:0 #b4b4b4, stop:1 #8f8f8f);
                border: 1px solid #5c5c5c;
                width: 18px;
                margin: -2px 0;
                border-radius: 3px;
            }
        """)
        
        layout = QVBoxLayout(self)
        layout.addWidget(self.slider)

Integration with Media Player​

class MediaPlayerControls(QWidget):
    def __init__(self):
        super().__init__()
        
        # Progress slider with click-to-seek
        self.progress_slider = QCustomQSlider()
        self.progress_slider.setOrientation(Qt.Horizontal)
        self.progress_slider.setMinimum(0)
        self.progress_slider.setMaximum(1000)  # High precision for media
        
        # Volume slider
        self.volume_slider = QCustomQSlider()
        self.volume_slider.setOrientation(Qt.Horizontal)
        self.volume_slider.setMinimum(0)
        self.volume_slider.setMaximum(100)
        self.volume_slider.setValue(80)
        
        # Connect signals
        self.progress_slider.sliderReleased.connect(self.on_progress_seek)
        self.volume_slider.valueChanged.connect(self.on_volume_changed)
        
        self.setup_ui()
    
    def setup_ui(self):
        layout = QVBoxLayout(self)
        layout.addWidget(QLabel("Progress:"))
        layout.addWidget(self.progress_slider)
        layout.addWidget(QLabel("Volume:"))
        layout.addWidget(self.volume_slider)
    
    def on_progress_seek(self):
        # Seek to clicked position in media
        position = self.progress_slider.value()
        print(f"Seeking to position: {position}")
    
    def on_volume_changed(self, volume):
        # Adjust volume based on slider value
        print(f"Volume changed to: {volume}%")

Advanced Usage with Custom Ranges​

class TemperatureControl(QWidget):
    def __init__(self):
        super().__init__()
        
        # Temperature slider with custom range
        self.temp_slider = QCustomQSlider()
        self.temp_slider.setOrientation(Qt.Horizontal)
        self.temp_slider.setMinimum(-10)  # -10°C
        self.temp_slider.setMaximum(40)   # 40°C
        self.temp_slider.setValue(20)     # Room temperature
        
        self.temp_label = QLabel("20°C")
        
        # Connect value changes
        self.temp_slider.valueChanged.connect(self.update_temperature_display)
        
        layout = QVBoxLayout(self)
        layout.addWidget(QLabel("Temperature Control:"))
        layout.addWidget(self.temp_slider)
        layout.addWidget(self.temp_label)
    
    def update_temperature_display(self, temperature):
        self.temp_label.setText(f"{temperature}°C")
        
        # Visual feedback for extreme temperatures
        if temperature < 0:
            self.temp_label.setStyleSheet("color: blue;")
        elif temperature > 30:
            self.temp_label.setStyleSheet("color: red;")
        else:
            self.temp_label.setStyleSheet("color: black;")

Technical Details​

Position Calculation​

The slider uses Qt's style system to accurately calculate values:

def pixelPosToRangeValue(self, pos):
    opt = QStyleOptionSlider()
    self.initStyleOption(opt)
    
    # Get slider groove and handle dimensions
    gr = self.style().subControlRect(QStyle.CC_Slider, opt, QStyle.SC_SliderGroove, self)
    sr = self.style().subControlRect(QStyle.CC_Slider, opt, QStyle.SC_SliderHandle, self)
    
    # Calculate available slider range
    if self.orientation() == Qt.Horizontal:
        sliderLength = sr.width()
        sliderMin = gr.x()
        sliderMax = gr.right() - sliderLength + 1
    else:
        sliderLength = sr.height()
        sliderMin = gr.y()
        sliderMax = gr.bottom() - sliderLength + 1
    
    # Convert pixel position to slider value
    pr = pos - sr.center() + sr.topLeft()
    p = pr.x() if self.orientation() == Qt.Horizontal else pr.y()
    
    return QStyle.sliderValueFromPosition(
        self.minimum(), self.maximum(), 
        p - sliderMin, sliderMax - sliderMin, 
        opt.upsideDown
    )

Signal Integration​

All standard QSlider signals are available:

  • valueChanged(int): Emitted when value changes
  • sliderPressed(): Emitted when slider interaction starts
  • sliderReleased(): Emitted when slider interaction ends
  • sliderMoved(int): Emitted during dragging

Benefits Over Standard QSlider​

Improved User Experience​

  • Faster Navigation: Click to jump to any position instantly
  • Better Precision: Accurate value selection without dragging
  • Mobile-Friendly: Larger touch targets for better accessibility

Maintained Compatibility​

  • Drop-in Replacement: Can replace QSlider without code changes
  • Style Preservation: Works with existing stylesheets and themes
  • Signal Compatibility: All standard signals behave identically

Performance​

  • Efficient Calculation: Uses Qt's optimized style system
  • Minimal Overhead: Only overrides necessary mouse events
  • Native Performance: No performance impact on value changes

Additional Notes​

  • Theme Compatibility:
    Works with all Qt styling systems and theme engines.

  • Accessibility:
    Enhanced accessibility through larger clickable areas.

  • Cross-Platform:
    Consistent behavior across Windows, macOS, and Linux.

  • Customization:
    Can be styled using standard QSlider stylesheets.

The QCustomQSlider is ideal for media players, configuration dialogs, settings panels, and any application where quick and precise value selection improves user experience.