BitMap¶

Inherits: Resource < RefCounted < Object

Boolean matrix.

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.

Methods¶

Image	convert_to_image ( ) const
void	create ( Vector2i size )
void	create_from_image_alpha ( Image image, float threshold=0.1 )
bool	get_bit ( int x, int y ) const
bool	get_bitv ( Vector2i position ) const
Vector2i	get_size ( ) const
int	get_true_bit_count ( ) const
void	grow_mask ( int pixels, Rect2i rect )
PackedVector2Array[]	opaque_to_polygons ( Rect2i rect, float epsilon=2.0 ) const
void	resize ( Vector2i new_size )
void	set_bit ( int x, int y, bool bit )
void	set_bit_rect ( Rect2i rect, bool bit )
void	set_bitv ( Vector2i position, bool bit )

Method Descriptions¶

Image convert_to_image ( ) const

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

void create ( Vector2i size )

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

void create_from_image_alpha ( Image image, 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.

bool get_bit ( int x, int y ) const

Returns bitmap's value at the specified position.

bool get_bitv ( Vector2i position ) const

Returns bitmap's value at the specified position.

Vector2i get_size ( ) const

Returns bitmap's dimensions.

int get_true_bit_count ( ) const

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

void grow_mask ( int pixels, 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 grow_mask.

PackedVector2Array[] opaque_to_polygons ( Rect2i rect, float epsilon=2.0 ) const

Creates an 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 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.

void resize ( Vector2i new_size )

Resizes the image to new_size.

void set_bit ( int x, int y, bool bit )

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

void set_bit_rect ( Rect2i rect, bool bit )

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

void set_bitv ( Vector2i position, bool bit )

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