godot-docs/classes/class_bitmap.rst

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.. _class_BitMap:

BitMap
======

**Inherits:** :ref:`Resource<class_Resource>` **<** :ref:`RefCounted<class_RefCounted>` **<** :ref:`Object<class_Object>`

Boolean matrix.

.. rst-class:: classref-introduction-group

Description
-----------

A two-dimensional array of boolean values, can be used to efficiently store a binary matrix (every matrix element takes only one bit) and query the values using natural cartesian coordinates.

.. rst-class:: classref-reftable-group

Methods
-------

.. table::
   :widths: auto

   +-------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`Image<class_Image>`                             | :ref:`convert_to_image<class_BitMap_method_convert_to_image>` **(** **)** |const|                                                                                |
   +-------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | void                                                  | :ref:`create<class_BitMap_method_create>` **(** :ref:`Vector2i<class_Vector2i>` size **)**                                                                       |
   +-------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | void                                                  | :ref:`create_from_image_alpha<class_BitMap_method_create_from_image_alpha>` **(** :ref:`Image<class_Image>` image, :ref:`float<class_float>` threshold=0.1 **)** |
   +-------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`bool<class_bool>`                               | :ref:`get_bit<class_BitMap_method_get_bit>` **(** :ref:`int<class_int>` x, :ref:`int<class_int>` y **)** |const|                                                 |
   +-------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`bool<class_bool>`                               | :ref:`get_bitv<class_BitMap_method_get_bitv>` **(** :ref:`Vector2i<class_Vector2i>` position **)** |const|                                                       |
   +-------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`Vector2i<class_Vector2i>`                       | :ref:`get_size<class_BitMap_method_get_size>` **(** **)** |const|                                                                                                |
   +-------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`int<class_int>`                                 | :ref:`get_true_bit_count<class_BitMap_method_get_true_bit_count>` **(** **)** |const|                                                                            |
   +-------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | void                                                  | :ref:`grow_mask<class_BitMap_method_grow_mask>` **(** :ref:`int<class_int>` pixels, :ref:`Rect2i<class_Rect2i>` rect **)**                                       |
   +-------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`PackedVector2Array[]<class_PackedVector2Array>` | :ref:`opaque_to_polygons<class_BitMap_method_opaque_to_polygons>` **(** :ref:`Rect2i<class_Rect2i>` rect, :ref:`float<class_float>` epsilon=2.0 **)** |const|    |
   +-------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | void                                                  | :ref:`resize<class_BitMap_method_resize>` **(** :ref:`Vector2i<class_Vector2i>` new_size **)**                                                                   |
   +-------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | void                                                  | :ref:`set_bit<class_BitMap_method_set_bit>` **(** :ref:`int<class_int>` x, :ref:`int<class_int>` y, :ref:`bool<class_bool>` bit **)**                            |
   +-------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | void                                                  | :ref:`set_bit_rect<class_BitMap_method_set_bit_rect>` **(** :ref:`Rect2i<class_Rect2i>` rect, :ref:`bool<class_bool>` bit **)**                                  |
   +-------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | void                                                  | :ref:`set_bitv<class_BitMap_method_set_bitv>` **(** :ref:`Vector2i<class_Vector2i>` position, :ref:`bool<class_bool>` bit **)**                                  |
   +-------------------------------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------------------+

.. rst-class:: classref-section-separator

----

.. rst-class:: classref-descriptions-group

Method Descriptions
-------------------

.. _class_BitMap_method_convert_to_image:

.. rst-class:: classref-method

:ref:`Image<class_Image>` **convert_to_image** **(** **)** |const|

Returns an image of the same size as the bitmap and with a :ref:`Format<enum_Image_Format>` of type :ref:`Image.FORMAT_L8<class_Image_constant_FORMAT_L8>`. ``true`` bits of the bitmap are being converted into white pixels, and ``false`` bits into black.

.. rst-class:: classref-item-separator

----

.. _class_BitMap_method_create:

.. rst-class:: classref-method

void **create** **(** :ref:`Vector2i<class_Vector2i>` size **)**

Creates a bitmap with the specified size, filled with ``false``.

.. rst-class:: classref-item-separator

----

.. _class_BitMap_method_create_from_image_alpha:

.. rst-class:: classref-method

void **create_from_image_alpha** **(** :ref:`Image<class_Image>` image, :ref:`float<class_float>` threshold=0.1 **)**

Creates a bitmap that matches the given image dimensions, every element of the bitmap is set to ``false`` if the alpha value of the image at that position is equal to ``threshold`` or less, and ``true`` in other case.

.. rst-class:: classref-item-separator

----

.. _class_BitMap_method_get_bit:

.. rst-class:: classref-method

:ref:`bool<class_bool>` **get_bit** **(** :ref:`int<class_int>` x, :ref:`int<class_int>` y **)** |const|

Returns bitmap's value at the specified position.

.. rst-class:: classref-item-separator

----

.. _class_BitMap_method_get_bitv:

.. rst-class:: classref-method

:ref:`bool<class_bool>` **get_bitv** **(** :ref:`Vector2i<class_Vector2i>` position **)** |const|

Returns bitmap's value at the specified position.

.. rst-class:: classref-item-separator

----

.. _class_BitMap_method_get_size:

.. rst-class:: classref-method

:ref:`Vector2i<class_Vector2i>` **get_size** **(** **)** |const|

Returns bitmap's dimensions.

.. rst-class:: classref-item-separator

----

.. _class_BitMap_method_get_true_bit_count:

.. rst-class:: classref-method

:ref:`int<class_int>` **get_true_bit_count** **(** **)** |const|

Returns the number of bitmap elements that are set to ``true``.

.. rst-class:: classref-item-separator

----

.. _class_BitMap_method_grow_mask:

.. rst-class:: classref-method

void **grow_mask** **(** :ref:`int<class_int>` pixels, :ref:`Rect2i<class_Rect2i>` rect **)**

Applies morphological dilation or erosion to the bitmap. If ``pixels`` is positive, dilation is applied to the bitmap. If ``pixels`` is negative, erosion is applied to the bitmap. ``rect`` defines the area where the morphological operation is applied. Pixels located outside the ``rect`` are unaffected by :ref:`grow_mask<class_BitMap_method_grow_mask>`.

.. rst-class:: classref-item-separator

----

.. _class_BitMap_method_opaque_to_polygons:

.. rst-class:: classref-method

:ref:`PackedVector2Array[]<class_PackedVector2Array>` **opaque_to_polygons** **(** :ref:`Rect2i<class_Rect2i>` rect, :ref:`float<class_float>` epsilon=2.0 **)** |const|

Creates an :ref:`Array<class_Array>` of polygons covering a rectangular portion of the bitmap. It uses a marching squares algorithm, followed by Ramer-Douglas-Peucker (RDP) reduction of the number of vertices. Each polygon is described as a :ref:`PackedVector2Array<class_PackedVector2Array>` of its vertices.

To get polygons covering the whole bitmap, pass:

::

    Rect2(Vector2(), get_size())

\ ``epsilon`` is passed to RDP to control how accurately the polygons cover the bitmap: a lower ``epsilon`` corresponds to more points in the polygons.

.. rst-class:: classref-item-separator

----

.. _class_BitMap_method_resize:

.. rst-class:: classref-method

void **resize** **(** :ref:`Vector2i<class_Vector2i>` new_size **)**

Resizes the image to ``new_size``.

.. rst-class:: classref-item-separator

----

.. _class_BitMap_method_set_bit:

.. rst-class:: classref-method

void **set_bit** **(** :ref:`int<class_int>` x, :ref:`int<class_int>` y, :ref:`bool<class_bool>` bit **)**

Sets the bitmap's element at the specified position, to the specified value.

.. rst-class:: classref-item-separator

----

.. _class_BitMap_method_set_bit_rect:

.. rst-class:: classref-method

void **set_bit_rect** **(** :ref:`Rect2i<class_Rect2i>` rect, :ref:`bool<class_bool>` bit **)**

Sets a rectangular portion of the bitmap to the specified value.

.. rst-class:: classref-item-separator

----

.. _class_BitMap_method_set_bitv:

.. rst-class:: classref-method

void **set_bitv** **(** :ref:`Vector2i<class_Vector2i>` position, :ref:`bool<class_bool>` bit **)**

Sets the bitmap's element at the specified position, to the specified value.

.. |virtual| replace:: :abbr:`virtual (This method should typically be overridden by the user to have any effect.)`
.. |const| replace:: :abbr:`const (This method has no side effects. It doesn't modify any of the instance's member variables.)`
.. |vararg| replace:: :abbr:`vararg (This method accepts any number of arguments after the ones described here.)`
.. |constructor| replace:: :abbr:`constructor (This method is used to construct a type.)`
.. |static| replace:: :abbr:`static (This method doesn't need an instance to be called, so it can be called directly using the class name.)`
.. |operator| replace:: :abbr:`operator (This method describes a valid operator to use with this type as left-hand operand.)`
.. |bitfield| replace:: :abbr:`BitField (This value is an integer composed as a bitmask of the following flags.)`