## gimplayer

gimplayer — Operations on a single layer.

## Synopsis

    gint32              gimp_layer_new                      (gint32 image_ID,
                                                             const gchar *name,
                                                             gint width,
                                                             gint height,
                                                             GimpImageType type,
                                                             gdouble opacity,
                                                             GimpLayerModeEffects mode);
    gint32              gimp_layer_copy                     (gint32 layer_ID);
    gboolean            gimp_layer_scale                    (gint32 layer_ID,
                                                             gint new_width,
                                                             gint new_height,
                                                             gboolean local_origin);
    gboolean            gimp_layer_resize                   (gint32 layer_ID,
                                                             gint new_width,
                                                             gint new_height,
                                                             gint offx,
                                                             gint offy);
    gboolean            gimp_layer_resize_to_image_size     (gint32 layer_ID);
    gboolean            gimp_layer_translate                (gint32 layer_ID,
                                                             gint offx,
                                                             gint offy);
    gboolean            gimp_layer_add_alpha                (gint32 layer_ID);
    gboolean            gimp_layer_flatten                  (gint32 layer_ID);
    gboolean            gimp_layer_set_offsets              (gint32 layer_ID,
                                                             gint offx,
                                                             gint offy);
    gint32              gimp_layer_create_mask              (gint32 layer_ID,
                                                             GimpAddMaskType mask_type);
    gint32              gimp_layer_from_mask                (gint32 mask_ID);
    gint32              gimp_layer_get_mask                 (gint32 layer_ID);
    gboolean            gimp_layer_add_mask                 (gint32 layer_ID,
                                                             gint32 mask_ID);
    gboolean            gimp_layer_remove_mask              (gint32 layer_ID,
                                                             GimpMaskApplyMode mode);
    gint32              gimp_layer_new_from_drawable        (gint32 drawable_ID,
                                                             gint32 dest_image_ID);
    gboolean            gimp_layer_get_lock_alpha           (gint32 layer_ID);
    gboolean            gimp_layer_set_lock_alpha           (gint32 layer_ID,
                                                             gboolean lock_alpha);
    gboolean            gimp_layer_get_preserve_trans       (gint32 layer_ID);
    gboolean            gimp_layer_set_preserve_trans       (gint32 layer_ID,
                                                             gboolean preserve_trans);
    gboolean            gimp_layer_get_apply_mask           (gint32 layer_ID);
    gboolean            gimp_layer_set_apply_mask           (gint32 layer_ID,
                                                             gboolean apply_mask);
    gboolean            gimp_layer_get_show_mask            (gint32 layer_ID);
    gboolean            gimp_layer_set_show_mask            (gint32 layer_ID,
                                                             gboolean show_mask);
    gboolean            gimp_layer_get_edit_mask            (gint32 layer_ID);
    gboolean            gimp_layer_set_edit_mask            (gint32 layer_ID,
                                                             gboolean edit_mask);
    gdouble             gimp_layer_get_opacity              (gint32 layer_ID);
    gboolean            gimp_layer_set_opacity              (gint32 layer_ID,
                                                             gdouble opacity);
    GimpLayerModeEffects gimp_layer_get_mode                (gint32 layer_ID);
    gboolean            gimp_layer_set_mode                 (gint32 layer_ID,
                                                             GimpLayerModeEffects mode);
    gboolean            gimp_layer_is_floating_sel          (gint32 layer_ID);

## Description

Operations on a single layer.

## Details

### gimp_layer_new ()

    gint32              gimp_layer_new                      (gint32 image_ID,
                                                             const gchar *name,
                                                             gint width,
                                                             gint height,
                                                             GimpImageType type,
                                                             gdouble opacity,
                                                             GimpLayerModeEffects mode);

Create a new layer.

This procedure creates a new layer with the specified width, height, and type. Name, opacity, and mode are also supplied parameters. The new layer still needs to be added to the image, as this is not automatic. Add the new layer with the 'gimp_image_add_layer' command. Other attributes such as layer mask modes, and offsets should be set with explicit procedure calls.

`image_ID` : | The image to which to add the layer.
`name` : | The layer name.
`width` : | The layer width.
`height` : | The layer height.
`type` : | The layer type.
`opacity` : | The layer opacity.
`mode` : | The layer combination mode.
Returns : | The newly created layer.

### gimp_layer_copy ()

    gint32              gimp_layer_copy                     (gint32 layer_ID);

Copy a layer.

This procedure copies the specified layer and returns the copy. The newly copied layer is for use within the original layer's image. It should not be subsequently added to any other image.

`layer_ID` : | The layer to copy.
Returns : | The newly copied layer.

### gimp_layer_scale ()

    gboolean            gimp_layer_scale                    (gint32 layer_ID,
                                                             gint new_width,
                                                             gint new_height,
                                                             gboolean local_origin);

Scale the layer to the specified extents.

This procedure scales the layer so that its new width and height are equal to the supplied parameters. The 'local-origin' parameter specifies whether to scale from the center of the layer, or from the image origin. This operation only works if the layer has been added to an image.

`layer_ID` : | The layer.
`new_width` : | New layer width.
`new_height` : | New layer height.
`local_origin` : | Use a local origin (as opposed to the image origin).
Returns : | TRUE on success.

### gimp_layer_resize ()

    gboolean            gimp_layer_resize                   (gint32 layer_ID,
                                                             gint new_width,
                                                             gint new_height,
                                                             gint offx,
                                                             gint offy);

Resize the layer to the specified extents.

This procedure resizes the layer so that its new width and height are equal to the supplied parameters. Offsets are also provided which describe the position of the previous layer's content. This operation only works if the layer has been added to an image.

`layer_ID` : | The layer.
`new_width` : | New layer width.
`new_height` : | New layer height.
`offx` : | x offset between upper left corner of old and new layers: (old - new).
`offy` : | y offset between upper left corner of old and new layers: (old - new).
Returns : | TRUE on success.

### gimp_layer_resize_to_image_size ()

    gboolean            gimp_layer_resize_to_image_size     (gint32 layer_ID);

Resize a layer to the image size.

This procedure resizes the layer so that it's new width and height are equal to the width and height of its image container.

`layer_ID` : | The layer to resize.
Returns : | TRUE on success.

### gimp_layer_translate ()

    gboolean            gimp_layer_translate                (gint32 layer_ID,
                                                             gint offx,
                                                             gint offy);

Translate the layer by the specified offsets.

This procedure translates the layer by the amounts specified in the x and y arguments. These can be negative, and are considered offsets from the current position. This command only works if the layer has been added to an image. All additional layers contained in the image which have the linked flag set to TRUE w ill also be translated by the specified offsets.

`layer_ID` : | The layer.
`offx` : | Offset in x direction.
`offy` : | Offset in y direction.
Returns : | TRUE on success.

### gimp_layer_add_alpha ()

    gboolean            gimp_layer_add_alpha                (gint32 layer_ID);

Add an alpha channel to the layer if it doesn't already have one.

This procedure adds an additional component to the specified layer if it does not already possess an alpha channel. An alpha channel makes it possible to clear and erase to transparency, instead of the background color. This transforms layers of type RGB to RGBA, GRAY to GRAYA, and INDEXED to INDEXEDA.

`layer_ID` : | The layer.
Returns : | TRUE on success.

### gimp_layer_flatten ()

    gboolean            gimp_layer_flatten                  (gint32 layer_ID);

Remove the alpha channel from the layer if it has one.

This procedure removes the alpha channel from a layer, blending all (partially) transparent pixels in the layer against the background color. This transforms layers of type RGBA to RGB, GRAYA to GRAY, and INDEXEDA to INDEXED.

`layer_ID` : | The layer.
Returns : | TRUE on success.

Since GIMP 2.4

### gimp_layer_set_offsets ()

    gboolean            gimp_layer_set_offsets              (gint32 layer_ID,
                                                             gint offx,
                                                             gint offy);

Set the layer offsets.

This procedure sets the offsets for the specified layer. The offsets are relative to the image origin and can be any values. This operation is valid only on layers which have been added to an image.

`layer_ID` : | The layer.
`offx` : | Offset in x direction.
`offy` : | Offset in y direction.
Returns : | TRUE on success.

### gimp_layer_create_mask ()

    gint32              gimp_layer_create_mask              (gint32 layer_ID,
                                                             GimpAddMaskType mask_type);

Create a layer mask for the specified specified layer.

This procedure creates a layer mask for the specified layer. Layer masks serve as an additional alpha channel for a layer. A number of different types of masks are allowed for initialisation: completely white masks (which will leave the layer fully visible), completely black masks (which will give the layer complete transparency, the layer's already existing alpha channel (which will leave the layer fully visible, but which may be more useful than a white mask), the current selection or a grayscale copy of the layer. The layer mask still needs to be added to the layer. This can be done with a call to `gimp_layer_add_mask()`.

`layer_ID` : | The layer to which to add the mask.
`mask_type` : | The type of mask.
Returns : | The newly created mask.

### gimp_layer_from_mask ()

    gint32              gimp_layer_from_mask                (gint32 mask_ID);

Get the specified mask's layer.

This procedure returns the specified mask's layer , or -1 if none exists.

`mask_ID` : | Mask for which to return the layer.
Returns : | The mask's layer.

Since GIMP 2.2

### gimp_layer_get_mask ()

    gint32              gimp_layer_get_mask                 (gint32 layer_ID);

Get the specified layer's mask if it exists.

This procedure returns the specified layer's mask, or -1 if none exists.

`layer_ID` : | The layer.
Returns : | The layer mask.

### gimp_layer_add_mask ()

    gboolean            gimp_layer_add_mask                 (gint32 layer_ID,
                                                             gint32 mask_ID);

Add a layer mask to the specified layer.

This procedure adds a layer mask to the specified layer. Layer masks serve as an additional alpha channel for a layer. This procedure will fail if a number of prerequisites aren't met. The layer cannot already have a layer mask. The specified mask must exist and have the same dimensions as the layer. The layer must have been created for use with the specified image and the mask must have been created with the procedure 'gimp-layer-create-mask'.

`layer_ID` : | The layer to receive the mask.
`mask_ID` : | The mask to add to the layer.
Returns : | TRUE on success.

### gimp_layer_remove_mask ()

    gboolean            gimp_layer_remove_mask              (gint32 layer_ID,
                                                             GimpMaskApplyMode mode);

Remove the specified layer mask from the layer.

This procedure removes the specified layer mask from the layer. If the mask doesn't exist, an error is returned.

`layer_ID` : | The layer from which to remove mask.
`mode` : | Removal mode.
Returns : | TRUE on success.

### gimp_layer_new_from_drawable ()

    gint32              gimp_layer_new_from_drawable        (gint32 drawable_ID,
                                                             gint32 dest_image_ID);

Create a new layer by copying an existing drawable.

This procedure creates a new layer as a copy of the specified drawable. The new layer still needs to be added to the image, as this is not automatic. Add the new layer with the `gimp_image_add_layer()` command. Other attributes such as layer mask modes, and offsets should be set with explicit procedure calls.

`drawable_ID` : | The source drawable from where the new layer is copied.
`dest_image_ID` : | The destination image to which to add the layer.
Returns : | The newly copied layer.

### gimp_layer_get_lock_alpha ()

    gboolean            gimp_layer_get_lock_alpha           (gint32 layer_ID);

Get the lock alpha channel setting of the specified layer.

This procedure returns the specified layer's lock alpha channel setting.

`layer_ID` : | The layer.
Returns : | The layer's lock alpha channel setting.

### gimp_layer_set_lock_alpha ()

    gboolean            gimp_layer_set_lock_alpha           (gint32 layer_ID,
                                                             gboolean lock_alpha);

Set the lock alpha channel setting of the specified layer.

This procedure sets the specified layer's lock alpha channel setting.

`layer_ID` : | The layer.
`lock_alpha` : | The new layer's lock alpha channel setting.
Returns : | TRUE on success.

### gimp_layer_get_preserve_trans ()

    gboolean            gimp_layer_get_preserve_trans       (gint32 layer_ID);

### Warning

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

This procedure is deprecated! Use `gimp_layer_get_lock_alpha()` instead.

`layer_ID` : | The layer.
Returns : | The layer's preserve transperancy setting.

### gimp_layer_set_preserve_trans ()

    gboolean            gimp_layer_set_preserve_trans       (gint32 layer_ID,
                                                             gboolean preserve_trans);

### Warning

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

This procedure is deprecated! Use `gimp_layer_set_lock_alpha()` instead.

`layer_ID` : | The layer.
`preserve_trans` : | The new layer's preserve transperancy setting.
Returns : | TRUE on success.

### gimp_layer_get_apply_mask ()

    gboolean            gimp_layer_get_apply_mask           (gint32 layer_ID);

Get the apply mask setting of the specified layer.

This procedure returns the specified layer's apply mask setting. If the value is TRUE, then the layer mask for this layer is currently being composited with the layer's alpha channel.

`layer_ID` : | The layer.
Returns : | The layer's apply mask setting.

### gimp_layer_set_apply_mask ()

    gboolean            gimp_layer_set_apply_mask           (gint32 layer_ID,
                                                             gboolean apply_mask);

Set the apply mask setting of the specified layer.

This procedure sets the specified layer's apply mask setting. This controls whether the layer's mask is currently affecting the alpha channel. If there is no layer mask, this function will return an error.

`layer_ID` : | The layer.
`apply_mask` : | The new layer's apply mask setting.
Returns : | TRUE on success.

### gimp_layer_get_show_mask ()

    gboolean            gimp_layer_get_show_mask            (gint32 layer_ID);

Get the show mask setting of the specified layer.

This procedure returns the specified layer's show mask setting. This controls whether the layer or its mask is visible. TRUE indicates that the mask should be visible. If the layer has no mask, then this function returns an error.

`layer_ID` : | The layer.
Returns : | The layer's show mask setting.

### gimp_layer_set_show_mask ()

    gboolean            gimp_layer_set_show_mask            (gint32 layer_ID,
                                                             gboolean show_mask);

Set the show mask setting of the specified layer.

This procedure sets the specified layer's show mask setting. This controls whether the layer's mask is currently affecting the alpha channel. If there is no layer mask, this function will return an error.

`layer_ID` : | The layer.
`show_mask` : | The new layer's show mask setting.
Returns : | TRUE on success.

### gimp_layer_get_edit_mask ()

    gboolean            gimp_layer_get_edit_mask            (gint32 layer_ID);

Get the edit mask setting of the specified layer.

This procedure returns the specified layer's edit mask setting. If the value is TRUE, then the layer mask for this layer is currently active, and not the layer.

`layer_ID` : | The layer.
Returns : | The layer's edit mask setting.

### gimp_layer_set_edit_mask ()

    gboolean            gimp_layer_set_edit_mask            (gint32 layer_ID,
                                                             gboolean edit_mask);

Set the edit mask setting of the specified layer.

This procedure sets the specified layer's edit mask setting. This controls whether the layer or it's mask is currently active for editing. If the specified layer has no layer mask, then this procedure will return an error.

`layer_ID` : | The layer.
`edit_mask` : | The new layer's edit mask setting.
Returns : | TRUE on success.

### gimp_layer_get_opacity ()

    gdouble             gimp_layer_get_opacity              (gint32 layer_ID);

Get the opacity of the specified layer.

This procedure returns the specified layer's opacity.

`layer_ID` : | The layer.
Returns : | The layer opacity.

### gimp_layer_set_opacity ()

    gboolean            gimp_layer_set_opacity              (gint32 layer_ID,
                                                             gdouble opacity);

Set the opacity of the specified layer.

This procedure sets the specified layer's opacity.

`layer_ID` : | The layer.
`opacity` : | The new layer opacity.
Returns : | TRUE on success.

### gimp_layer_get_mode ()

    GimpLayerModeEffects gimp_layer_get_mode                (gint32 layer_ID);

Get the combination mode of the specified layer.

This procedure returns the specified layer's combination mode.

`layer_ID` : | The layer.
Returns : | The layer combination mode.

### gimp_layer_set_mode ()

    gboolean            gimp_layer_set_mode                 (gint32 layer_ID,
                                                             GimpLayerModeEffects mode);

Set the combination mode of the specified layer.

This procedure sets the specified layer's combination mode.

`layer_ID` : | The layer.
`mode` : | The new layer combination mode.
Returns : | TRUE on success.

### gimp_layer_is_floating_sel ()

    gboolean            gimp_layer_is_floating_sel          (gint32 layer_ID);

Is the specified layer a floating selection?

This procedure returns whether the layer is a floating selection. Floating selections are special cases of layers which are attached to a specific drawable.

`layer_ID` : | The layer.
Returns : | TRUE if the layer is a floating selection.