LuminanceSource class abstract
The purpose of this class hierarchy is to abstract different bitmap implementations across platforms into a standard interface for requesting greyscale luminance values. The interface only provides immutable methods; therefore crop and rotation create copies. This is to ensure that one Reader does not modify the original luminance source and leave it in an unknown state for other Readers in the chain.
@author dswitkin@google.com (Daniel Switkin)
Constructors
- LuminanceSource.new(int _width, int _height)
Properties
- hashCode → int
-
The hash code for this object.
no setterinherited
- height → int
-
Get the height of the bitmap.
no setter
- isCropSupported → bool
-
Get whether this subclass supports cropping.
no setter
- isRotateSupported → bool
-
Get whether this subclass supports counter-clockwise rotation.
no setter
- matrix → Uint8List
-
Fetches luminance data for the underlying bitmap. Values should be fetched using:
{@code int luminance = array
y * width + x}no setter - runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- width → int
-
Get the width of the bitmap.
no setter
Methods
-
crop(
int left, int top, int width, int height) → LuminanceSource - Returns a new object with cropped image data. Implementations may keep a reference to the original data rather than a copy. Only callable if isCropSupported() is true.
-
getRow(
int y, Uint8List? row) → Uint8List - Fetches one row of luminance data from the underlying platform's bitmap. Values range from 0 (black) to 255 (white). Because Java does not have an unsigned byte type, callers will have to bitwise and with 0xff for each value. It is preferable for implementations of this method to only fetch this row rather than the whole image, since no 2D Readers may be installed and matrix may never be called.
-
invert(
) → LuminanceSource - Get a wrapper of this LuminanceSource which inverts the luminances it returns -- black becomes white and vice versa, and each value becomes (255-value).
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
rotateCounterClockwise(
) → LuminanceSource - Get a rotated version of this object.
-
rotateCounterClockwise45(
) → LuminanceSource - Get a rotated version of this object.
-
toString(
) → String -
A string representation of this object.
override
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited