## PhatKnob

PhatKnob —

## Synopsis

                PhatKnob;
    GtkWidget*  phat_knob_new                   (GtkAdjustment *adjustment);
    GtkWidget*  phat_knob_new_with_range        (double value,
                                                 double lower,
                                                 double upper,
                                                 double step);
    GtkAdjustment* phat_knob_get_adjustment     (PhatKnob *knob);
    double      phat_knob_get_value             (PhatKnob *knob);
    void        phat_knob_set_value             (PhatKnob *knob,
                                                 double value);
    void        phat_knob_set_range             (PhatKnob *knob,
                                                 double lower,
                                                 double upper);
    void        phat_knob_set_update_policy     (PhatKnob *knob,
                                                 GtkUpdateType policy);
    void        phat_knob_set_adjustment        (PhatKnob *knob,
                                                 GtkAdjustment *adjustment);
    void        phat_knob_set_log               (PhatKnob *knob,
                                                 gboolean is_log);
    gboolean    phat_knob_is_log                (PhatKnob *knob);

## Description

## Details

### PhatKnob

    typedef struct {
        GtkWidget widget;
        /* The adjustment object that stores the data for this knob */
        GtkAdjustment *adjustment;
        GtkAdjustment* adjustment_prv;

        /* update policy (GTK_UPDATE_[CONTINUOUS/DELAYED/DISCONTINUOUS]) */
        guint policy : 2;
        gboolean is_log;

        /* State of widget (to do with user interaction) */
        guint8 state;
        gint saved_x, saved_y;

        /* ID of update timer, or 0 if none */
        guint32 timer;

        /* Pixmap for knob */
        GdkPixbuf *pixbuf;
        GdkBitmap *mask;
        GdkGC *mask_gc;
        GdkGC *red_gc;

        /* Old values from adjustment stored so we know when something changes */
        gfloat old_value;
        gfloat old_lower;
        gfloat old_upper;
    } PhatKnob;

### phat_knob_new ()

    GtkWidget*  phat_knob_new                   (GtkAdjustment *adjustment);

`adjustment` : |
Returns : |

### phat_knob_new_with_range ()

    GtkWidget*  phat_knob_new_with_range        (double value,
                                                 double lower,
                                                 double upper,
                                                 double step);

Creates a new PhatKnob. The knob will create a new GtkAdjustment from `value`, `lower`, `upper`, and `step`. If these parameters represent a bogus configuration, the program will terminate.

`value` : | the initial value the new knob should have
`lower` : | the lowest value the new knob will allow
`upper` : | the highest value the new knob will allow
`step` : | increment added or subtracted when turning
Returns : | a newly created PhatKnob

### phat_knob_get_adjustment ()

    GtkAdjustment* phat_knob_get_adjustment     (PhatKnob *knob);

`knob` : |
Returns : |

### phat_knob_get_value ()

    double      phat_knob_get_value             (PhatKnob *knob);

Retrieves the current value of the knob.

`knob` : | a PhatKnob
Returns : | current value of the knob

### phat_knob_set_value ()

    void        phat_knob_set_value             (PhatKnob *knob,
                                                 double value);

Sets the current value of the knob. If the value is outside the range of values allowed by `knob`, it will be clamped. The knob emits the "value-changed" signal if the value changes.

`knob` : | a PhatKnob
`value` : | a new value for the knob

### phat_knob_set_range ()

    void        phat_knob_set_range             (PhatKnob *knob,
                                                 double lower,
                                                 double upper);

Sets the range of allowable values for the knob, and clamps the knob's current value to be between `lower` and `upper`.

`knob` : | a PhatKnob
`lower` : | lowest allowable value
`upper` : | highest allowable value

### phat_knob_set_update_policy ()

    void        phat_knob_set_update_policy     (PhatKnob *knob,
                                                 GtkUpdateType policy);

`knob` : |
`policy` : |

### phat_knob_set_adjustment ()

    void        phat_knob_set_adjustment        (PhatKnob *knob,
                                                 GtkAdjustment *adjustment);

`knob` : |
`adjustment` : |

### phat_knob_set_log ()

    void        phat_knob_set_log               (PhatKnob *knob,
                                                 gboolean is_log);

`knob` : |
`is_log` : |

### phat_knob_is_log ()

    gboolean    phat_knob_is_log                (PhatKnob *knob);

`knob` : |
Returns : |