A GtkObject representing an adjustable bounded value
Class GtkAdjustment( [value],[lower],[upper],[step_increment],[page_increment],[page_size] )
| value | the current value. |
| lower | the minimum value. |
| upper | the maximum value. |
| step_increment | the increment to use to make minor changes to the value. In a GtkScrollbar this increment is used when the mouse is clicked on the arrows at the top and bottom of the scrollbar, to scroll by a small amount. |
| page_increment | the increment to use to make major changes to the value. In a GtkScrollbar this increment is used when the mouse is clicked in the trough, to scroll by a large amount. |
| page_size | the page size. In a GtkScrollbar this is the size of the area which is currently visible. |
The GtkAdjustment object represents a value which has an associated lower and upper bound, together with step and page increments, and a page size. It is used within several GTK+ widgets, including GtkSpinButton, GtkViewport, and GtkRange (which is a base class for GtkHScrollbar, GtkVScrollbar, GtkHScale, and GtkVScale).
The GtkAdjustment object does not update the value itself. Instead it is left up to the owner of the GtkAdjustment to control the value.
The owner of the GtkAdjustment typically calls the gtk_adjustment_value_changed() and gtk_adjustment_changed() functions after changing the value and its bounds. This results in the emission of the "value_changed" or "changed" signal respectively.
| Methods | |
| changed | Emits a "changed" signal from the GtkAdjustment. |
| clamp_page | Updates the GtkAdjustment value to ensure that the range between lower and upper is in the current page (i.e. between value and value + page_size). |
| configure | Sets all properties of the adjustment at once. |
| get_lower | Retrieves the minimum value of the adjustment. |
| get_page_increment | Retrieves the page increment of the adjustment. |
| get_page_size | Retrieves the page size of the adjustment. |
| get_step_increment | Retrieves the step increment of the adjustment. |
| get_upper | Retrieves the maximum value of the adjustment. |
| get_value | Gets the current value of the adjustment. |
| set_lower | Sets the minimum value of the adjustment. |
| set_page_increment | Sets the page increment of the adjustment. |
| set_page_size | Sets the page size of the adjustment. |
| set_step_increment | Sets the step increment of the adjustment. |
| set_upper | Sets the maximum value of the adjustment. |
| set_value | Sets the GtkAdjustment value. |
| signal_changed | Emitted when one or more of the GtkAdjustment fields have been changed, other than the value field. |
| signal_value_changed | Emitted when the GtkAdjustment value field has been changed. |
| value_changed | Emits a "value_changed" signal from the GtkAdjustment. |
Emits a "changed" signal from the GtkAdjustment.
GtkAdjustment.changed()
This is typically called by the owner of the GtkAdjustment after it has changed any of the GtkAdjustment fields other than the value.
Updates the GtkAdjustment value to ensure that the range between lower and upper is in the current page (i.e. between value and value + page_size).
GtkAdjustment.clamp_page( lower, upper )
| lower | the lower value |
| upper | the upper value |
If the range is larger than the page size, then only the start of it will be in the current page. A "changed" signal will be emitted if the value is changed.
Sets all properties of the adjustment at once.
GtkAdjustment.configure( value, lower, upper, step_increment, page_increment, page_size )
| value | the new value. |
| lower | the new minimum value. |
| upper | the new maximum value. |
| step_increment | the step increment. |
| page_increment | the page increment. |
| page_size | the page size. |
Use this function to avoid multiple emissions of the "changed" signal. See gtk_adjustment_set_lower() for an alternative way of compressing multiple emissions of "changed" into one.
Retrieves the minimum value of the adjustment.
GtkAdjustment.get_lower()
| Return | The current minimum value of the adjustment. |
Retrieves the page increment of the adjustment.
GtkAdjustment.get_page_increment()
| Return | The current page increment of the adjustment. |
Retrieves the page size of the adjustment.
GtkAdjustment.get_page_size()
| Return | The current page size of the adjustment. |
Retrieves the step increment of the adjustment.
GtkAdjustment.get_step_increment()
| Return | The current step increment of the adjustment. |
Retrieves the maximum value of the adjustment.
GtkAdjustment.get_upper()
| Return | The current maximum value of the adjustment. |
Gets the current value of the adjustment.
GtkAdjustment.get_value()
| Return | The current value of the adjustment. |
Sets the minimum value of the adjustment.
GtkAdjustment.set_lower( lower )
| lower | the new minimum value |
When setting multiple adjustment properties via their individual setters, multiple "changed" signals will be emitted. However, since the emission of the "changed" signal is tied to the emission of the "GObject::notify" signals of the changed properties, it's possible to compress the "changed" signals into one by calling g_object_freeze_notify() and g_object_thaw_notify() around the calls to the individual setters.
Alternatively, using a single g_object_set() for all the properties to change, or using gtk_adjustment_configure() has the same effect of compressing "changed" emissions.
Sets the page increment of the adjustment.
GtkAdjustment.set_page_increment( page_increment )
| page_increment | the new page increment |
See gtk_adjustment_set_lower() about how to compress multiple emissions of the "changed" signal when setting multiple adjustment properties.
Sets the page size of the adjustment.
GtkAdjustment.set_page_size( page_size )
| page_size | the new page size |
See gtk_adjustment_set_lower() about how to compress multiple emissions of the "changed" signal when setting multiple adjustment properties.
Sets the step increment of the adjustment.
GtkAdjustment.set_step_increment( step_increment )
| step_increment | the new step increment |
See gtk_adjustment_set_lower() about how to compress multiple emissions of the "changed" signal when setting multiple adjustment properties.
Sets the maximum value of the adjustment.
GtkAdjustment.set_upper()
Note that values will be restricted by upper - page-size if the page-size property is nonzero.
See gtk_adjustment_set_lower() about how to compress multiple emissions of the "changed" signal when setting multiple adjustment properties.
Sets the GtkAdjustment value.
GtkAdjustment.set_value( value )
| value | the new value The value is clamped to lie between adjustment->lower and adjustment->upper. |
Note that for adjustments which are used in a GtkScrollbar, the effective range of allowed values goes from adjustment->lower to adjustment->upper - adjustment->page_size.
Emitted when one or more of the GtkAdjustment fields have been changed, other than the value field.
GtkAdjustment.signal_changed()
Emitted when the GtkAdjustment value field has been changed.
GtkAdjustment.signal_value_changed()
Emits a "value_changed" signal from the GtkAdjustment.
GtkAdjustment.value_changed()
This is typically called by the owner of the GtkAdjustment after it has changed the GtkAdjustment value field.