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Lets-Plot Kotlin API without dependencies.
/*
* Copyright (c) 2023 JetBrains s.r.o.
* Use of this source code is governed by the MIT license that can be found in the LICENSE file.
*
* This file has been modified by JetBrains : Java code has been converted to Kotlin code.
*
* THE FOLLOWING IS THE COPYRIGHT OF THE ORIGINAL DOCUMENT:
*
* Copyright (c) 2009-2012, Hernán J. González.
* Licensed under the Apache License, Version 2.0.
*
* The original PNGJ library is written in Java and can be found here: [PNGJ](https://github.com/leonbloy/pngj).
*/
@file:Suppress("KDocUnresolvedReference")
package org.jetbrains.letsPlot.util.pngj
import org.jetbrains.letsPlot.util.pngj.ImageLineHelper.getMaskForPackedFormats
/**
* Represents an image line, integer format (one integer by sample). See
* [.scanline] to understand the format.
*/
internal class ImageLineInt(imgInfo: ImageInfo, sci: IntArray?) : IImageLine, IImageLineArray {
val imgInfo: ImageInfo
/**
* @return see [.scanline]
*/
/**
* The 'scanline' is an array of integers, corresponds to an image line
* (row).
*
*
* Each `int` is a "sample" (one for channel), (0-255 or 0-65535)
* in the corresponding PNG sequence: `R G B R G B...` or
* `R G B A R G B A... or `g g g ...` or
* `i i i` (palette index)
` *
*
* For bitdepth=1/2/4 the value is not scaled (hence, eg, if bitdepth=2 the
* range will be 0-4)
*
*
* To convert a indexed line to RGB values, see
* [ImageLineHelper.palette2rgb]
* (you can't do the reverse)
*/
val scanline: IntArray
/**
* @see .size
*/
/**
* number of elements in the scanline
*/
override val size: Int
/**
* informational ; only filled by the reader. not meaningful for interlaced
*/
override var filterType: FilterType = FilterType.FILTER_UNKNOWN
/**
* @param imgInfo
* Inmutable ImageInfo, basic parameters of the image we are
* reading or writing
*/
constructor(imgInfo: ImageInfo) : this(imgInfo, null)
/**
* @param imgInfo
* Inmutable ImageInfo, basic parameters of the image we are
* reading or writing
* @param sci
* prealocated buffer (can be null)
*/
init {
this.imgInfo = imgInfo
filterType = FilterType.FILTER_UNKNOWN
size = imgInfo.samplesPerRow
scanline = if (sci != null && sci.size >= size) sci else IntArray(size)
}
/**
* Basic info
*/
override fun toString(): String {
return " cols=" + imgInfo.cols + " bpc=" + imgInfo.bitDepth + " size=" + scanline.size
}
override fun readFromPngRaw(raw: ByteArray, len: Int, offset: Int, step: Int) {
filterType = FilterType.getByVal(raw[0].toInt())
val len1 = len - 1
val step1: Int = (step - 1) * imgInfo.channels
if (imgInfo.bitDepth == 8) {
if (step == 1) { // 8bispp non-interlaced: most important case, should be optimized
for (i in 0 until size) {
scanline[i] = raw[i + 1].toInt() and 0xff
}
} else { // 8bispp interlaced
var s = 1
var c = 0
var i: Int = offset * imgInfo.channels
while (s <= len1) {
scanline[i] = raw[s].toInt() and 0xff
c++
if (c == imgInfo.channels) {
c = 0
i += step1
}
s++
i++
}
}
} else if (imgInfo.bitDepth == 16) {
if (step == 1) { // 16bispp non-interlaced
var i = 0
var s = 1
while (i < size) {
scanline[i] = raw[s++].toInt() and 0xFF shl 8 or (raw[s++].toInt() and 0xFF) // 16 bitspc
i++
}
} else {
var s = 1
var c = 0
var i = if (offset != 0) offset * imgInfo.channels else 0
while (s <= len1) {
scanline[i] = raw[s++].toInt() and 0xFF shl 8 or (raw[s].toInt() and 0xFF) // 16 bitspc
c++
if (c == imgInfo.channels) {
c = 0
i += step1
}
s++
i++
}
}
} else { // packed formats
val mask0: Int
var mask: Int
var shi: Int
val bd: Int = imgInfo.bitDepth
mask0 = getMaskForPackedFormats(bd)
var i: Int = offset * imgInfo.channels
var r = 1
var c = 0
while (r < len) {
mask = mask0
shi = 8 - bd
do {
scanline[i++] = raw[r].toInt() and mask shr shi
mask = mask shr bd
shi -= bd
c++
if (c == imgInfo.channels) {
c = 0
i += step1
}
} while (mask != 0 && i < size)
r++
}
}
}
override fun writeToPngRaw(raw: ByteArray) {
raw[0] = filterType.value.toByte()
when (imgInfo.bitDepth) {
8 -> {
for (i in 0 until size) {
raw[i + 1] = scanline[i].toByte()
}
}
16 -> {
var i = 0
var s = 1
while (i < size) {
raw[s++] = (scanline[i] shr 8).toByte()
raw[s++] = (scanline[i] and 0xff).toByte()
i++
}
}
else -> { // packed formats
var shi: Int
var v: Int
val bd: Int = imgInfo.bitDepth
shi = 8 - bd
v = 0
var i = 0
var r = 1
while (i < size) {
v = v or (scanline[i] shl shi)
shi -= bd
if (shi < 0 || i == size - 1) {
raw[r++] = v.toByte()
shi = 8 - bd
v = 0
}
i++
}
}
}
}
/**
* Does nothing in this implementation
*/
override fun endReadFromPngRaw() {}
override fun getElem(i: Int): Int {
return scanline[i]
}
override val imageInfo: ImageInfo
get() = imgInfo
companion object {
/**
* Helper method, returns a default factory for this object
*
*/
val factory: IImageLineFactory
get() = object : IImageLineFactory {
override fun createImageLine(iminfo: ImageInfo): ImageLineInt {
return ImageLineInt(iminfo)
}
}
}
}