GtkCurve

GTK+ Reference Manual
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Object Hierarchy

  GtkObject
   +----GtkWidget
         +----GtkDrawingArea
               +----GtkCurve

Signal Prototypes

"curve-type-changed"
            void        user_function      (GtkCurve *curve,
                                            gpointer user_data);

Description

The GtkCurve widget allows the user to edit a curve covering a range of values. It is typically used to fine-tune color balances in graphics applications like the Gimp.

The GtkCurve widget has 3 modes of operation - spline, linear and free. In spline mode the user places points on the curve which are automatically connected together into a smooth curve. In linear mode the user places points on the curve which are connected by straight lines. In free mode the user can draw the points of the curve freely, and they are not connected at all.

Details

struct GtkCurve

struct GtkCurve;

gtk_curve_new ()

GtkWidget*  gtk_curve_new                   (void);

Creates a new GtkCurve.

Returns :

a new GtkCurve.

gtk_curve_reset ()

void        gtk_curve_reset                 (GtkCurve *curve);

Resets the curve to a straight line from the minimum x & y values to the maximum x & y values (i.e. from the bottom-left to the top-right corners). The curve type is not changed.

curve : a GtkCurve.

gtk_curve_set_gamma ()

void        gtk_curve_set_gamma             (GtkCurve *curve,
                                             gfloat gamma);

Recomputes the entire curve using the given gamma value. A gamma value of 1 results in a straight line. Values greater than 1 result in a curve above the straight line. Values less than 1 result in a curve below the straight line. The curve type is changed to GTK_CURVE_TYPE_FREE. FIXME: Needs a more precise definition of gamma.

`curve` :	a GtkCurve.
`gamma` :	the gamma value.

gtk_curve_set_range ()

void        gtk_curve_set_range             (GtkCurve *curve,
                                             gfloat min_x,
                                             gfloat max_x,
                                             gfloat min_y,
                                             gfloat max_y);

Sets the minimum and maximum x & y values of the curve. The curve is also reset with a call to gtk_curve_reset().

`curve` :	a GtkCurve.
`min_x` :	the minimum x value.
`max_x` :	the maximum x value.
`min_y` :	the minimum y value.
`max_y` :	the maximum y value.

gtk_curve_get_vector ()

void        gtk_curve_get_vector            (GtkCurve *curve,
                                             int veclen,
                                             gfloat vector[]);

Returns a vector of points representing the curve.

`curve` :	a GtkCurve.
`veclen` :	the number of points to calculate.
`vector` :	returns the points.

gtk_curve_set_vector ()

void        gtk_curve_set_vector            (GtkCurve *curve,
                                             int veclen,
                                             gfloat vector[]);

Sets the vector of points on the curve. The curve type is set to GTK_CURVE_TYPE_FREE.

`curve` :	a GtkCurve.
`veclen` :	the number of points.
`vector` :	the points on the curve.

gtk_curve_set_curve_type ()

void        gtk_curve_set_curve_type        (GtkCurve *curve,
                                             GtkCurveType type);

Sets the type of the curve. The curve will remain unchanged except when changing from a free curve to a linear or spline curve, in which case the curve will be changed as little as possible.

`curve` :	a GtkCurve.
`type` :	the type of the curve.

Signals

The "curve-type-changed" signal

void        user_function                  (GtkCurve *curve,
                                            gpointer user_data);

Emitted when the curve type has been changed. The curve type can be changed explicitly with a call to gtk_curve_set_curve_type(). It is also changed as a side-effect of calling gtk_curve_reset() or gtk_curve_set_gamma().

`curve` :	the object which received the signal.
`user_data` :	user data set when the signal handler was connected.