ImageLineHelper (PNGJ 2.0.1 API)

java.lang.Object
- ar.com.hjg.pngj.ImageLineHelper

```
public class ImageLineHelper
extends Object
```
Bunch of utility static methods to proces an image line at the pixel level.
WARNING: this has little testing/optimizing, and this API is not stable. some methods will probably be changed or removed if future releases.
WARNING: most methods for getting/setting values work currently only for ImageLine or ImageLineByte

Constructor Summary

Constructors
Constructor and Description

ImageLineHelper()

Constructors
Constructor and Description
`ImageLineHelper()`

Method Summary

Methods
Modifier and Type	Method and Description
`static int`	`clampTo_0_255(int i)`
`static int`	`clampTo_0_65535(int i)`
`static int`	`clampTo_128_127(int x)`
`static int`	`double2int(ImageLineInt line, double d)`
`static int`	`double2intClamped(ImageLineInt line, double d)`
`static int`	`getPixelARGB8(IImageLine line, int column)`
`static int`	`getPixelRGB8(IImageLine line, int column)` integer packed R G B only for bitdepth=8! (does not check!)
`static String`	`infoFirstLastPixels(ImageLineInt line)` Just for basic info or debugging.
`static double`	`int2double(ImageLineInt line, int p)`
`static double`	`int2doubleClamped(ImageLineInt line, int p)`
`static int`	`interpol(int a, int b, int c, int d, double dx, double dy)`
`static int[]`	`palette2rgb(ImageLineInt line, PngChunkPLTE pal, int[] buf)`
`static int[]`	`palette2rgb(ImageLineInt line, PngChunkPLTE pal, PngChunkTRNS trns, int[] buf)` Given an indexed line with a palette, unpacks as a RGB array, or RGBA if a non nul PngChunkTRNS chunk is passed
`static int[]`	`palette2rgba(ImageLineInt line, PngChunkPLTE pal, PngChunkTRNS trns, int[] buf)` Same as palette2rgbx , but returns rgba always, even if trns is null
`static void`	`scaleDown(IImageLineArray line)` Reverse of `scaleUp(IImageLineArray)`
`static byte`	`scaleDown(int bitdepth, byte v)`
`static void`	`scaleUp(IImageLineArray line)` When the bitdepth is less than 8, the imageLine is usually returned/expected unscaled.
`static byte`	`scaleUp(int bitdepth, byte v)`
`static void`	`setPixelRGB8(ImageLineInt line, int col, int rgb)`
`static void`	`setPixelRGB8(ImageLineInt line, int col, int r, int g, int b)`
`static void`	`setPixelRGBA8(ImageLineInt line, int col, int rgb)`
`static void`	`setPixelRGBA8(ImageLineInt line, int col, int r, int g, int b, int a)`
`static void`	`setPixelsRGB8(ImageLineInt line, int[] rgb)`
`static void`	`setPixelsRGBA8(ImageLineInt line, int[] rgb)`
`static void`	`setValD(ImageLineInt line, int i, double d)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail
- ImageLineHelper
```
public ImageLineHelper()
```

Method Detail

scaleUp
```
public static void scaleUp(IImageLineArray line)
```
When the bitdepth is less than 8, the imageLine is usually returned/expected unscaled. This method upscales it in place. Eg, if bitdepth=1, values 0-1 will be converted to 0-255

scaleDown

public static void scaleDown(IImageLineArray line)

Reverse of scaleUp(IImageLineArray)

scaleUp

public static byte scaleUp(int bitdepth,
           byte v)

scaleDown

public static byte scaleDown(int bitdepth,
             byte v)

palette2rgb
```
public static int[] palette2rgb(ImageLineInt line,
                PngChunkPLTE pal,
                PngChunkTRNS trns,
                int[] buf)
```
Given an indexed line with a palette, unpacks as a RGB array, or RGBA if a non nul PngChunkTRNS chunk is passed

Parameters:
line - ImageLine as returned from PngReader
pal - Palette chunk
trns - Transparency chunk, can be null (absent)
buf - Preallocated array, optional

Returns:
R G B (A), one sample 0-255 per array element. Ready for pngw.writeRowInt()

palette2rgba
```
public static int[] palette2rgba(ImageLineInt line,
                 PngChunkPLTE pal,
                 PngChunkTRNS trns,
                 int[] buf)
```
Same as palette2rgbx , but returns rgba always, even if trns is null

Parameters:
line - ImageLine as returned from PngReader
pal - Palette chunk
trns - Transparency chunk, can be null (absent)
buf - Preallocated array, optional

Returns:
R G B (A), one sample 0-255 per array element. Ready for pngw.writeRowInt()

palette2rgb

public static int[] palette2rgb(ImageLineInt line,
                PngChunkPLTE pal,
                int[] buf)

infoFirstLastPixels
```
public static String infoFirstLastPixels(ImageLineInt line)
```
Just for basic info or debugging. Shows values for first and last pixel. Does not include alpha

getPixelRGB8

public static int getPixelRGB8(IImageLine line,
               int column)

integer packed R G B only for bitdepth=8! (does not check!)

getPixelARGB8

public static int getPixelARGB8(IImageLine line,
                int column)

setPixelsRGB8

public static void setPixelsRGB8(ImageLineInt line,
                 int[] rgb)

setPixelRGB8

public static void setPixelRGB8(ImageLineInt line,
                int col,
                int r,
                int g,
                int b)

setPixelRGB8

public static void setPixelRGB8(ImageLineInt line,
                int col,
                int rgb)

setPixelsRGBA8

public static void setPixelsRGBA8(ImageLineInt line,
                  int[] rgb)

setPixelRGBA8

public static void setPixelRGBA8(ImageLineInt line,
                 int col,
                 int r,
                 int g,
                 int b,
                 int a)

setPixelRGBA8

public static void setPixelRGBA8(ImageLineInt line,
                 int col,
                 int rgb)

setValD

public static void setValD(ImageLineInt line,
           int i,
           double d)

interpol

public static int interpol(int a,
           int b,
           int c,
           int d,
           double dx,
           double dy)

int2double

public static double int2double(ImageLineInt line,
                int p)

int2doubleClamped

public static double int2doubleClamped(ImageLineInt line,
                       int p)

double2int

public static int double2int(ImageLineInt line,
             double d)

double2intClamped

public static int double2intClamped(ImageLineInt line,
                    double d)

clampTo_0_255

public static int clampTo_0_255(int i)

clampTo_0_65535

public static int clampTo_0_65535(int i)

clampTo_128_127

public static int clampTo_128_127(int x)

Class ImageLineHelper

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

ImageLineHelper

Method Detail

scaleUp

scaleDown

scaleUp

scaleDown

palette2rgb

palette2rgba

palette2rgb

infoFirstLastPixels

getPixelRGB8

getPixelARGB8

setPixelsRGB8

setPixelRGB8

setPixelRGB8

setPixelsRGBA8

setPixelRGBA8

setPixelRGBA8

setValD

interpol

int2double

int2doubleClamped

double2int

double2intClamped

clampTo_0_255

clampTo_0_65535

clampTo_128_127