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

void

create ( Vector2 size )

void

create_from_image_alpha ( Image image, float threshold=0.1 )

bool

get_bit ( Vector2 position ) const

Vector2

get_size ( ) const

int

get_true_bit_count ( ) const

void

grow_mask ( int pixels, Rect2 rect )

Array

opaque_to_polygons ( Rect2 rect, float epsilon=2.0 ) const

void

set_bit ( Vector2 position, bool bit )

void

set_bit_rect ( Rect2 rect, bool bit )

Method Descriptions

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.


Returns bitmap's value at the specified position.


Returns bitmap's dimensions.


  • int get_true_bit_count ( ) const

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


  • void grow_mask ( int pixels, Rect2 rect )

Applies morphological dilation to the bitmap. The first argument is the dilation amount, Rect2 is the area where the dilation will be applied.


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.


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


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