PixelMap

Kotlin |Java

class PixelMap

kotlin.Any
↳	androidx.compose.ui.graphics.PixelMap

Result of a pixel read operation. This contains the ImageAsset pixel information represented as a 1 dimensional array of values that supports queries of pixel values based on the 2 dimensional coordinates of the corresponding ImageAsset this was obtained from

import androidx.compose.ui.graphics.PixelMap

val imageAsset = createImageAsset()

val buffer = IntArray(20 * 10)
imageAsset.readPixels(
    buffer = buffer,
    startX = 8,
    startY = 9,
    width = 20,
    height = 10
)

val pixelmap = PixelMap(
    buffer = buffer,
    width = 20,
    height = 10,
    stride = 20,
    bufferOffset = 0
)

// create a histogram to count the number of occurrences of a color within the specified
// subsection of the provided ImageAsset
val histogram = HashMap<Color, Int>()
for (x in 0 until pixelmap.width) {
    for (y in 0 until pixelmap.height) {
        val color = pixelmap[x, y]
        val colorCount = histogram[color] ?: 0
        histogram[color] = (colorCount + 1)
    }
}

Summary

Public constructors
`<init>(buffer: IntArray, width: Int, height: Int, bufferOffset: Int, stride: Int)` Result of a pixel read operation.

Public methods
operator Color	`get(@IntRange(0) x: Int, @IntRange(0) y: Int)` Obtain the color of the pixel at the given coordinate

Properties
IntArray	`buffer` IntArray where pixel information is stored as an ARGB value packed into an Int
Int	`bufferOffset` first index in the buffer where pixel information for the ImageAsset is stored
Int	`height` Height of the subsection of the ImageAsset this buffer represents
Int	`stride` Number of entries to skip between rows
Int	`width` Width of the subsection of the ImageAsset this buffer represents

Public constructors

<init>

PixelMap(
    buffer: IntArray, 
    width: Int, 
    height: Int, 
    bufferOffset: Int, 
    stride: Int)

import androidx.compose.ui.graphics.PixelMap

val imageAsset = createImageAsset()

val buffer = IntArray(20 * 10)
imageAsset.readPixels(
    buffer = buffer,
    startX = 8,
    startY = 9,
    width = 20,
    height = 10
)

val pixelmap = PixelMap(
    buffer = buffer,
    width = 20,
    height = 10,
    stride = 20,
    bufferOffset = 0
)

// create a histogram to count the number of occurrences of a color within the specified
// subsection of the provided ImageAsset
val histogram = HashMap<Color, Int>()
for (x in 0 until pixelmap.width) {
    for (y in 0 until pixelmap.height) {
        val color = pixelmap[x, y]
        val colorCount = histogram[color] ?: 0
        histogram[color] = (colorCount + 1)
    }
}

Parameters
buffer: IntArray	IntArray where pixel information is stored as an ARGB value packed into an Int
bufferOffset: Int	first index in the buffer where pixel information for the ImageAsset is stored
width: Int	Width of the subsection of the ImageAsset this buffer represents
height: Int	Height of the subsection of the ImageAsset this buffer represents
stride: Int	Number of entries to skip between rows

See Also

Public methods

get

operator fun get(
    @IntRange(0) x: Int, 
    @IntRange(0) y: Int
): Color

Obtain the color of the pixel at the given coordinate

Properties

buffer

val buffer: IntArray

IntArray where pixel information is stored as an ARGB value packed into an Int

bufferOffset

val bufferOffset: Int

first index in the buffer where pixel information for the ImageAsset is stored

height

val height: Int

Height of the subsection of the ImageAsset this buffer represents

stride

val stride: Int

Number of entries to skip between rows

width

val width: Int

Width of the subsection of the ImageAsset this buffer represents