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The QDial class provides a rounded range control (like a speedometer or potentiometer). More...
#include <qdial.h>
Inherits QWidget and QRangeControl.
The QDial class provides a rounded range control (like a speedometer or potentiometer).
QDial is used when the user needs to control a value within a program-definable range, and the range either wraps around (typically, 0-359 degrees) or the dialog layout needs a square widget.
Both API- and UI-wise, the dial is very like a slider. Indeed, when wrapping() is FALSE (the default) there is no hard difference between a slider and a dial. They have the same signals, slots and member functions, all of which do the same things. Which one to use depends only on your taste and on the application.
The dial initially emits valueChanged() signals continuously while the slider is being moved; you can make it emit the signal less often by calling setTracking( FALSE ). dialMoved() is emitted continuously even when tracking() is FALSE.
The slider also emits dialPressed() and dialReleased() signals when the mouse button is pressed and released. But note that the dial's value can change without these signals being emitted; the keyboard and wheel can be used to change the value.
Unlike the slider, QDial attempts to draw a "nice" number of notches rather than one per lineStep(). If possible, that number is lineStep(), but if there aren't enough pixels to draw every, QDial will draw every second, third or something. notchSize() returns the number of units per notch, hopefully a multiple of lineStep(); setNotchTarget() sets the target distance between neighbouring notches in pixels. The default is 3.75 pixels.
Like the slider, the dial makes the QRangeControl functions setValue(), addLine(), substractLine(), addPage() and subtractPage() available as slots.
The dial's keyboard interface is fairly simple: The left/up and right/down arrow keys move by lineStep(), page up and page down by pageStep() and Home and End to minValue() and maxValue().
See also QScrollBar, QSpinBox and GUI Design Handbook: Slider.
value is forced to be within the legal range.
This signal is emitted whenever the dial value changes. The frequency of this signal is not influenced by setTracking().
See also valueChanged(int).
This signal is emitted when the use begins mouse interaction with the dial.
See also dialReleased().
This signal is emitted when the use ends mouse interaction with the dial.
See also dialPressed().
Returns the current line step. See the "lineStep" property for details.
Returns the current maximum value. See the "maxValue" property for details.
Returns the current minimum value. See the "minValue" property for details.
Returns the current notch size. See the "notchSize" property for details.
Returns the target size of the notch. See the "notchTarget" property for details.
Returns TRUE whether the notches are shown, otherwise returns FALSE. See the "notchesVisible" property for details.
Returns the current page step. See the "pageStep" property for details.
Reimplemented from QRangeControl.
Sets the current line step. See the "lineStep" property for details.
Sets the current maximum value. See the "maxValue" property for details.
Sets the current minimum value. See the "minValue" property for details.
Sets the target size of the notch. See the "notchTarget" property for details.
Sets whether the notches are shown to b. See the "notchesVisible" property for details.
Sets the current page step. See the "pageStep" property for details.
Sets wether tracking is enabled to enable. See the "tracking" property for details.
Sets the current dial value. See the "value" property for details.
Sets whether wrapping is enabled to on. See the "wrapping" property for details.
Returns wether tracking is enabled. See the "tracking" property for details.
Returns the current dial value. See the "value" property for details.
Reimplemented from QRangeControl.
This signal is emitted whenever the dial value changes. The frequency of this signal is influenced by setTracking().
Returns TRUE whether wrapping is enabled, otherwise returns FALSE. See the "wrapping" property for details.
This property holds the current line step.
setLineStep() calls the virtual stepChange() function if the new line step is different from the previous setting.
Set this property's value with setLineStep() and get this property's value with lineStep().
See also QRangeControl::setSteps(), pageStep and setRange().
This property holds the current maximum value.
Set this property's value with setMaxValue() and get this property's value with maxValue().
See also setRange().
This property holds the current minimum value.
Set this property's value with setMinValue() and get this property's value with minValue().
See also setRange().
This property holds the current notch size.
The notch size is in range control units, not pixels, and if possible it is a multiple of lineStep() that results in an on-screen notch size near notchTarget().
Get this property's value with notchSize().
See also notchTarget and lineStep.
This property holds the target size of the notch.
The notch target is the number of pixels QDial attempts to put between each little line.
The actual size differs a bit from the target.
Set this property's value with setNotchTarget() and get this property's value with notchTarget().
This property holds whether the notches are shown.
Enables or disables showing of notches. If TRUE, the notches are shown, else not.
Set this property's value with setNotchesVisible() and get this property's value with notchesVisible().
This property holds the current page step.
setPageStep() calls the virtual stepChange() function if the new page step is different from the previous setting.
Set this property's value with setPageStep() and get this property's value with pageStep().
See also stepChange().
This property holds wether tracking is enabled.
If TRUE, tracking is enabled. This means that the arrow can be moved using the mouse. Otherwise this is not possible, the default is TRUE.
Set this property's value with setTracking() and get this property's value with tracking().
This property holds the current dial value.
This is guaranteed to be within the range [minValue ... maxValue].
Set this property's value with setValue() and get this property's value with value().
See also minValue and maxValue.
This property holds whether wrapping is enabled.
If TRUE, wrapping is enabled. This means that the arrow can be turned around 360°. Otherwise there is some space at the bottom which is skipped by the arrow.
Set this property's value with setWrapping() and get this property's value with wrapping().
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