## GwyLayerMask

GwyLayerMask — Display data as color mask

## Synopsis

    #include <libgwydgets/gwydgets.h>

                        GwyLayerMask;
                        GwyLayerMaskClass;
    GwyPixmapLayer*     gwy_layer_mask_new                  (void);
    void                gwy_layer_mask_set_color_key        (GwyLayerMask *mask_layer,
                                                             const gchar *prefix);
    const gchar*        gwy_layer_mask_get_color_key        (GwyLayerMask *mask_layer);
    GwyRGBA             gwy_layer_mask_get_color            (GwyLayerMask *mask_layer);

## Object Hierarchy

      GObject
       +----GInitiallyUnowned
             +----GtkObject
                   +----GwyDataViewLayer
                         +----GwyPixmapLayer
                               +----GwyLayerMask

## Properties

      "color-key"                gchar*                : Read / Write

## Description

GwyLayerMask is a data view layer that can paint data as a color mask with varying opacity. It is not normally usable outside a GwyDataView.

The layer takes all infromation from its parent GwyDataView, therefore you do not set its properties directly, but you change them in the corresponding GwyContainer and/or use methods like `gwy_layer_mask_set_color_key()` to make the layer read a different value from the container.

## Details

### GwyLayerMask

    typedef struct _GwyLayerMask GwyLayerMask;

### GwyLayerMaskClass

    typedef struct {
        GwyPixmapLayerClass parent_class;

        void (*reserved1)(void);
        void (*reserved2)(void);
    } GwyLayerMaskClass;

### gwy_layer_mask_new ()

    GwyPixmapLayer*     gwy_layer_mask_new                  (void);

Creates a new mask layer.

By default, is uses a transparent color (thus not displaying anything).

Returns : | The newly created layer.

### gwy_layer_mask_set_color_key ()

    void                gwy_layer_mask_set_color_key        (GwyLayerMask *mask_layer,
                                                             const gchar *prefix);

Sets the container key of colour components of a mask layer.

`mask_layer` : | A mask layer.
`prefix` : | Prefix of keys identifying mask color components, "/red", "/green", "/blue", and "/alpha" is appended to it to get the individual keys.

### gwy_layer_mask_get_color_key ()

    const gchar*        gwy_layer_mask_get_color_key        (GwyLayerMask *mask_layer);

Gets prefix identifying color components.

`mask_layer` : | A mask layer.
Returns : | The prefix, or `NULL` if it isn't set.

### gwy_layer_mask_get_color ()

    GwyRGBA             gwy_layer_mask_get_color            (GwyLayerMask *mask_layer);

Returns the color used by a mask layer.

`mask_layer` : | A mask layer.
Returns : | The color as GwyRGBA.

## Property Details

### The `"color-key"` property

      "color-key"                gchar*                : Read / Write

The :color-key property is the container key used to identify mask color in container.

Default value: NULL

## See Also

GwyDataView -- data display widget, GwyLayerBasic -- display data colored with a gradient, GwyRGBA -- color representation