## GtkCurve

GtkCurve — Allows direct editing of a curve

## Synopsis

    #include <gtk/gtk.h>

    struct              GtkCurve;
    GtkWidget *         gtk_curve_new                       (void);
    void                gtk_curve_reset                     (GtkCurve *curve);
    void                gtk_curve_set_gamma                 (GtkCurve *curve,
                                                             gfloat gamma_);
    void                gtk_curve_set_range                 (GtkCurve *curve,
                                                             gfloat min_x,
                                                             gfloat max_x,
                                                             gfloat min_y,
                                                             gfloat max_y);
    void                gtk_curve_get_vector                (GtkCurve *curve,
                                                             int veclen,
                                                             gfloat vector[]);
    void                gtk_curve_set_vector                (GtkCurve *curve,
                                                             int veclen,
                                                             gfloat vector[]);
    void                gtk_curve_set_curve_type            (GtkCurve *curve,
                                                             GtkCurveType type);

## Object Hierarchy

      GObject
       +----GInitiallyUnowned
             +----GtkObject
                   +----GtkWidget
                         +----GtkDrawingArea
                               +----GtkCurve

## Implemented Interfaces

GtkCurve implements AtkImplementorIface and GtkBuildable.

## Properties

      "curve-type"               GtkCurveType          : Read / Write
      "max-x"                    gfloat                : Read / Write
      "max-y"                    gfloat                : Read / Write
      "min-x"                    gfloat                : Read / Write
      "min-y"                    gfloat                : Read / Write

## Signals

      "curve-type-changed"                             : Run First

## 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.

As of GTK+ 2.20, GtkCurve has been deprecated since it is too specialized.

## Details

### struct GtkCurve

    struct GtkCurve;

### Warning

`GtkCurve` is deprecated and should not be used in newly-written code.

The GtkCurve struct contains private data only, and should be accessed using the functions below.

### gtk_curve_new ()

    GtkWidget *         gtk_curve_new                       (void);

### Warning

`gtk_curve_new` has been deprecated since version 2.20 and should not be used in newly-written code. Don't use this widget anymore.

Creates a new GtkCurve.

Returns : | a new GtkCurve.

### gtk_curve_reset ()

    void                gtk_curve_reset                     (GtkCurve *curve);

### Warning

`gtk_curve_reset` has been deprecated since version 2.20 and should not be used in newly-written code. Don't use this widget anymore.

Resets the curve to a straight line from the minimum x and y values to the maximum x and 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_);

### Warning

`gtk_curve_set_gamma` has been deprecated since version 2.20 and should not be used in newly-written code. Don't use this widget anymore.

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);

### Warning

`gtk_curve_set_range` has been deprecated since version 2.20 and should not be used in newly-written code. Don't use this widget anymore.

Sets the minimum and maximum x and 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[]);

### Warning

`gtk_curve_get_vector` has been deprecated since version 2.20 and should not be used in newly-written code. Don't use this widget anymore.

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[]);

### Warning

`gtk_curve_set_vector` has been deprecated since version 2.20 and should not be used in newly-written code. Don't use this widget anymore.

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);

### Warning

`gtk_curve_set_curve_type` has been deprecated since version 2.20 and should not be used in newly-written code. Don't use this widget anymore.

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.

## Property Details

### The `"curve-type"` property

      "curve-type"               GtkCurveType          : Read / Write

Is this curve linear, spline interpolated, or free-form.

Default value: GTK_CURVE_TYPE_SPLINE

### The `"max-x"` property

      "max-x"                    gfloat                : Read / Write

Maximum possible X value.

Default value: 1

### The `"max-y"` property

      "max-y"                    gfloat                : Read / Write

Maximum possible value for Y.

Default value: 1

### The `"min-x"` property

      "min-x"                    gfloat                : Read / Write

Minimum possible value for X.

Default value: 0

### The `"min-y"` property

      "min-y"                    gfloat                : Read / Write

Minimum possible value for Y.

Default value: 0

## Signal Details

### The `"curve-type-changed"` signal

    void                user_function                      (GtkCurve *curve,
                                                            gpointer  user_data)      : Run First

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.

## See Also

GtkGammaCurve | a subclass for editing gamma curves.