gimpundo

## gimpundo gimpundo — Control of undo/redo. |

## Synopsis

    gboolean            gimp_image_undo_group_start         (gint32 image_ID);
    gboolean            gimp_image_undo_group_end           (gint32 image_ID);
    gboolean            gimp_image_undo_is_enabled          (gint32 image_ID);
    gboolean            gimp_image_undo_disable             (gint32 image_ID);
    gboolean            gimp_image_undo_enable              (gint32 image_ID);
    gboolean            gimp_image_undo_freeze              (gint32 image_ID);
    gboolean            gimp_image_undo_thaw                (gint32 image_ID);

## Description

Control of undo/redo.

## Details

### gimp_image_undo_group_start ()

    gboolean            gimp_image_undo_group_start         (gint32 image_ID);

Starts a group undo.

This function is used to start a group undo--necessary for logically combining two or more undo operations into a single operation. This call must be used in conjunction with a `gimp_image_undo_group_end()` call.

`image_ID` : | The ID of the image in which to open an undo group.
Returns : | TRUE on success.

### gimp_image_undo_group_end ()

    gboolean            gimp_image_undo_group_end           (gint32 image_ID);

Finish a group undo.

This function must be called once for each `gimp_image_undo_group_start()` call that is made.

`image_ID` : | The ID of the image in which to close an undo group.
Returns : | TRUE on success.

### gimp_image_undo_is_enabled ()

    gboolean            gimp_image_undo_is_enabled          (gint32 image_ID);

Check if the image's undo stack is enabled.

This procedure checks if the image's undo stack is currently enabled or disabled. This is useful when several plugins or scripts call each other and want to check if their caller has already used `gimp_image_undo_disable()` or `gimp_image_undo_freeze()`.

`image_ID` : | The image.
Returns : | TRUE if undo is enabled for this image.

### gimp_image_undo_disable ()

    gboolean            gimp_image_undo_disable             (gint32 image_ID);

Disable the image's undo stack.

This procedure disables the image's undo stack, allowing subsequent operations to ignore their undo steps. This is generally called in conjunction with `gimp_image_undo_enable()` to temporarily disable an image undo stack. This is advantageous because saving undo steps can be time and memory intensive.

`image_ID` : | The image.
Returns : | TRUE if the image undo has been disabled.

### gimp_image_undo_enable ()

    gboolean            gimp_image_undo_enable              (gint32 image_ID);

Enable the image's undo stack.

This procedure enables the image's undo stack, allowing subsequent operations to store their undo steps. This is generally called in conjunction with `gimp_image_undo_disable()` to temporarily disable an image undo stack.

`image_ID` : | The image.
Returns : | TRUE if the image undo has been enabled.

### gimp_image_undo_freeze ()

    gboolean            gimp_image_undo_freeze              (gint32 image_ID);

Freeze the image's undo stack.

This procedure freezes the image's undo stack, allowing subsequent operations to ignore their undo steps. This is generally called in conjunction with `gimp_image_undo_thaw()` to temporarily disable an image undo stack. This is advantageous because saving undo steps can be time and memory intensive. `gimp_image_undo_freeze()` / `gimp_image_undo_thaw()` and `gimp_image_undo_disable()` / `gimp_image_undo_enable()` differ in that the former does not free up all undo steps when undo is thawed, so is more suited to interactive in-situ previews. It is important in this case that the image is back to the same state it was frozen in before thawing, else 'undo' behaviour is undefined.

`image_ID` : | The image.
Returns : | TRUE if the image undo has been frozen.

### gimp_image_undo_thaw ()

    gboolean            gimp_image_undo_thaw                (gint32 image_ID);

Thaw the image's undo stack.

This procedure thaws the image's undo stack, allowing subsequent operations to store their undo steps. This is generally called in conjunction with `gimp_image_undo_freeze()` to temporarily freeze an image undo stack. `gimp_image_undo_thaw()` does NOT free the undo stack as `gimp_image_undo_enable()` does, so is suited for situations where one wishes to leave the undo stack in the same state in which one found it despite non-destructively playing with the image in the meantime. An example would be in-situ plugin previews. Balancing freezes and thaws and ensuring image consistancy is the responsibility of the caller.

`image_ID` : | The image.
Returns : | TRUE if the image undo has been thawed.