Pixmap¶

A Pixmap object contains a color raster image (short for pixel map). The components in a pixel in the Pixmap are all byte values, with the transparency as the last component.

A Pixmap also has a location (x, y) in addition to its size; so that they can easily be used to represent tiles of a page.

Constructors¶

class Pixmap(colorspace, bbox, alpha)¶

class Pixmap(pixmap, mask)

Create a new empty Pixmap whose pixel data is not initialized. Alternatively create a new Pixmap based on an existing Pixmap without alpha and combine it with a single component soft mask of the same dimensions.

Arguments:

colorspace (ColorSpace | null) – The desired colorspace for the new pixmap. null implies a single component alpha pixmap.
bbox (Rect) – The desired dimensions of the new pixmap.
alpha (boolean) – Whether the new pixmap should have an alpha component.
pixmap (Pixmap) – The original pixmap without alpha.
mask (Pixmap) – Soft mask used as alpha in the combined pixmap.

var pixmap1 = new mupdf.Pixmap(mupdf.ColorSpace.DeviceRGB, [0, 0, 100, 100], true)
var pixmap2 = new mupdf.Pixmap(
        new mupdf.Image("photo.png").toPixmap(),
        new mupdf.Image("softmask.png").toPixmap()
)

Instance methods¶

Pixmap.prototype.clear(value)¶

Clear the pixels to the specified value. Pass 255 for white, 0 for black, or omit for transparent.

Arguments:

value (number) – The value to use for clearing.

pixmap.clear(255)

Pixmap.prototype.getBounds()¶

Return the pixmap bounds.

Returns:: Rect

var rect = pixmap.getBounds()

Pixmap.prototype.getWidth()¶

Get the width of the pixmap.

Returns:: number

var w = pixmap.getWidth()

Pixmap.prototype.getHeight()¶

Get the height of the pixmap.

Returns:: number

var h = pixmap.getHeight()

Pixmap.prototype.getNumberOfComponents()¶

Number of colors; plus one if an alpha channel is present.

Returns:: number

var num = pixmap.getNumberOfComponents()

Pixmap.prototype.getAlpha()¶

Returns whether an alpha channel is present.

Returns:: boolean

var alpha = pixmap.getAlpha()

Pixmap.prototype.getStride()¶

Number of bytes per row.

Returns:: number

var stride = pixmap.getStride()

Pixmap.prototype.getColorSpace()¶

Returns the colorspace of this pixmap. Returns null if the pixmap has no colors (for example if it is an opacity mask with only an alpha channel).

Returns:: ColorSpace | null

var cs = pixmap.getColorSpace()

Pixmap.prototype.setResolution(x, y)¶

Set horizontal and vertical resolution.

Arguments:

x (number) – Horizontal resolution in dots per inch.
y (number) – Vertical resolution in dots per inch.

pixmap.setResolution(300, 300)

Pixmap.prototype.getX()¶

Returns the x coordinate of the pixmap.

var x = pixmap.getX()

Pixmap.prototype.getY()¶

Returns the y coordinate of the pixmap.

Returns:: number

var y = pixmap.getY()

Pixmap.prototype.getXResolution()¶

Returns the horizontal resolution in dots per inch for this pixmap.

Returns:: number

var xRes = pixmap.getXResolution()

Pixmap.prototype.getYResolution()¶

Returns the vertical resolution in dots per inch for this pixmap.

Returns:: number

var yRes = pixmap.getYResolution()

Pixmap.prototype.invert()¶

Invert all pixels. All components are processed, except alpha which is unchanged.

pixmap.invert()

Pixmap.prototype.invertLuminance()¶

Transform all pixels so that luminance of each pixel is inverted, and the chrominance remains as unchanged as possible. All components are processed, except alpha which is unchanged.

pixmap.invertLuminance()

Pixmap.prototype.gamma(p)¶

Apply gamma correction to this pixmap. All components are processed, except alpha which is unchanged.

Values >= 0.1 & < 1 darkens the pixmap, > 1 & < 10 lightens the pixmap.

Arguments:

p (number) – Desired gamma level.

pixmap.gamma(3.5)

Pixmap.prototype.tint(black, white)¶

Tint all pixels in RGB, BGR or Gray pixmaps. Map black and white respectively to the given hex RGB values.

Arguments:

black (Color | number) – Map black to this color.
white (Color | number) – Map white to this color.

pixmap.tint(0xffff00, 0xffff00)

Pixmap.prototype.warp(points, width, height)¶

Return a warped subsection of this pixmap, where the corner of the input quadrilateral will be “warped” to become the four corner points of the returned pixmap defined by the requested dimensions.

Arguments:

points (Quad) – The corners of a convex quadrilateral within the Pixmap to be warped.
width (number) – Width of resulting pixmap.
height (number) – Height of resulting pixmap.

Returns:

Pixmap

var warpedPixmap = pixmap.warp([[0, 0], [100, 100], [130, 170], [150, 200]], 200, 200)

Pixmap.prototype.autowarp(points)¶

only mutool run

Same as Pixmap.prototype.warp() except that width and height are automatically determined.

Arguments:

points (Quad) – The corners of a convex quadrilateral within the Pixmap to be warped.

Returns:

Pixmap

var warpedPixmap = pixmap.autowarp([0,0,100,0,0,100,100,100])

Pixmap.prototype.convertToColorSpace(colorspace, keepAlpha)¶

Convert pixmap into a new pixmap of a desired colorspace. A proofing colorspace, a set of default colorspaces and color parameters used during conversion may be specified. Finally a boolean indicates if alpha should be preserved (default is to not preserve alpha).

Arguments:

colorspace (ColorSpace) – The desired colorspace.
keepAlpha (boolean) – Whether to keep the alpha component.

Returns:

Pixmap

Pixmap.prototype.getPixels()¶

Returns an array of pixels for this pixmap.

Returns:: Array of number

var pixels = pixmap.getPixels()

Pixmap.prototype.asPNG()¶

Returns a buffer of this pixmap as a PNG.

Returns:: Buffer

var buffer = pixmap.asPNG()

Pixmap.prototype.asPSD()¶

Returns a buffer of this pixmap as a PSD.

Returns:: Buffer

var buffer = pixmap.asPSD()

Pixmap.prototype.asPAM()¶

Returns a buffer of this pixmap as a PAM.

Returns:: Buffer

var buffer = pixmap.asPAM()

Pixmap.prototype.asJPEG(quality, invert_cmyk)¶

Returns a buffer of this pixmap as a JPEG. Note, if this pixmap has an alpha channel then an exception will be thrown.

Arguments:

quality (number) – Desired compression quality, between 0 and 100.
invert_cmyk (boolean) – How to handle polarity in CMYK JPEG images.

Returns:

Buffer

var buffer = pixmap.asJPEG(80, false)

Pixmap.prototype.decodeBarcode(rotate)¶

only mutool run

Decodes a barcode detected in the pixmap, and returns an object with properties for barcode type and contents.

Arguments:

rotate (number) – Degrees of rotation to rotate pixmap before detecting barcode. Defaults to 0.

Returns:

Object with barcode information.

var barcodeInfo = displayList.decodeBarcode([0, 0, 100, 100 ], 0)

Pixmap.prototype.encodeBarcode(barcodeType, contents, size, errorCorrectionLevel, quietZones, humanReadableText)¶

only mutool run

Encodes a barcode into a pixmap. The supported types of barcode is either one of:

Matrix		Linear Product		Linear Industrial
String	Name	String	Name	String	Name
`qrcode`	QR Code	`upca`	UPC-A	`code39`	Code 39
`microqrcode`	Micro QR Code	`upce`	UPC-E	`code93`	Code 93
`rmqrcode`	rMQR Code	`ean8`	EAN-8	`code128`	Code 128
`aztec`	Aztec	`ean13`	EAN-13	`codabar`	Codabar
`datamatrix`	DataMatrix	`databar`	DataBar	`databarexpanded`	DataBar Expanded
`pdf417`	PDF417	`databarlimited`	DataBar Limited	`dxfilmedge`	DX Film Edge
`maxicode`	MaxiCode			`itf`	ITF

Arguments:

barcodeType (string) – The desired barcode type.
contents (string) – The textual content to encode into the barcode.
size (number) – The size of the barcode in pixels.
errorCorrectionLevel (number) – The error correction level (0-8).
quietZones (boolean) – Whether to add an empty margin around the barcode.
humanReadableText (boolean) – Whether to add human-readable text. Some barcodes, e.g. EAN-13, can have the barcode contents printed in human-readable text next to the barcode.

Returns:

Pixmap

var pix = Pixmap.encodeBarcode("qrcode", "Hello world!", 100, 2, true, false)

Pixmap.prototype.getSample(x, y, index)¶

only mutool run

Get the value of component index at position x, y (relative to the image origin: 0, 0 is the top left pixel).

Arguments:

x (number) – X coordinate.
y (number) – Y coordinate.
index (number) – Component index. i.e. For CMYK ColorSpaces 0 = Cyan, 3 = Black, for RGB 0 = Red, 2 == Blue etc.

Throws:

RangeError if x, y, or index are out of range.

Returns:

number

// Get green component of pixel at 10, 10
var sample = rgbpixmap.getSample(10, 10, 1)

Pixmap.prototype.saveAsPNG(filename)¶

only mutool run

Save this Pixmap as a PNG. Only works for gray and RGB images.

Arguments:

filename (string) – Desired name of image file.

pixmap.saveAsPNG("filename.png")

Pixmap.prototype.saveAsJPEG(filename, quality)¶

only mutool run

Save this Pixmap as a JPEG file. Only works for gray, RGB and CMYK images.

Arguments:

filename (string) – Desired name of image file.
quality (number) – Desired quality between 0 and 100. Defaults to 90.

pixmap.saveAsJPEG("filename.jpg", 80)

Pixmap.prototype.saveAsPAM(filename)¶

only mutool run

Save this Pixmap as a PAM file.

Arguments:

filename (string) – Desired name of image file.

pixmap.saveAsPAM("filename.pam")

Pixmap.prototype.saveAsPNM(filename)¶

only mutool run

Save this Pixmap as a PNM file. Only works for gray and RGB images without alpha.

Arguments:

filename (string) – Desired name of image file.

pixmap.saveAsPNM("filename.pnm")

Pixmap.prototype.saveAsPBM(filename)¶

only mutool run

Save this Pixmap as a PBM file. Only works for alpha only, gray and CMYK images without alpha.

Arguments:

filename (string) – Desired name of image file.

pixmap.saveAsPBM("filename.pbm")

Pixmap.prototype.saveAsPKM(filename)¶

only mutool run

Save this Pixmap as a PKM file. Only works for alpha only, gray and CMYK images without alpha.

Arguments:

filename (string) – Desired name of image file.

pixmap.saveAsPKM("filename.pkm")

Pixmap.prototype.saveAsJPX(filename, quality)¶

only mutool run

Save this Pixmap as a JPX file.

Arguments:

filename (string) – Desired name of image file.
quality (number) – Desired quality between 0 and 100. Defaults to 90.

pixmap.saveAsJPX("filename.jpx", 90)

Pixmap.prototype.detectDocument(points)¶

only mutool run

Detect a “document” in a Pixmap. Only a grayscale Pixmap without alpha is supported, anything else will cause an exception to be thrown.

Returns null if no document was detected.

Returns:: Quad | null

var documentLocation = pixmap.detectDocument([0,0,100,0,100,100,0,100])

Pixmap.prototype.detectSkew()¶

only mutool run

Returns the angle of skew detected from Pixmap. Note, if the Pixmap is not Greyscale with no alpha then an exception will be thrown.

Returns:: number

var angle = pixmap.detectSkew()

Pixmap.prototype.deskew(angle, border)¶

only mutool run

Returns a new Pixmap being the deskewed version of the supplied Pixmap. Note, if a Pixmap is supplied that is not RGB or Greyscale, or has alpha then an exception will be thrown.

Arguments:

angle (number) – The angle to deskew.
border (string) – “increase” increases the size of the pixmap so no pixels are lost. “maintain” maintains the size of the pixmap. “decrease” decreases the size of the page so no new pixels are shown.

Returns:

Pixmap

var deskewed = pixmap.deskew(angle, 0)

Pixmap.prototype.computeMD5()¶

only mutool run

Returns the MD5 digest of the pixmap pixel data. The digest is returned as a string of 16 hex digits.

Returns:: string

var md5 = pixmap.computeMD5()