image

type Dict struct {
	// Width is the width of the image in pixels.
	Width int

	// Height is the height of the image in pixels.
	Height int

	// ColorSpace is the color space in which image samples are specified.
	// It can be any type of color space except Pattern.
	ColorSpace color.Space

	// BitsPerComponent is the number of bits used to represent each color component.
	// The value must be 1, 2, 4, 8, or (from PDF 1.5) 16.
	BitsPerComponent int

	// Decode (optional) is an array of numbers describing how to map image
	// samples into the range of values appropriate for the image's color
	// space. The slice must have twice the number of color components in the
	// ColorSpace.
	Decode []float64

	// WriteData is a function that writes the image data to the provided
	// writer. The data should be written row by row, with each row containing
	// Width * ColorSpace.Channels() samples, each sample using
	// BitsPerComponent bits.
	WriteData func(io.Writer) error

	// MaskImage (optional) determines which parts of the image are to be
	// painted.
	//
	// Only one of MaskImage or MaskColors may be specified.
	MaskImage *Mask

	// MaskColors (optional) defines color ranges for transparency masking.
	// Contains pairs [min1, max1, min2, max2, ...] for each color component.
	// Each value must be in the range 0 to (2^BitsPerComponent - 1) and
	// represents raw color values before any Decode array processing. Pixels
	// with all components in their respective ranges become transparent.
	//
	// Only one of MaskImage or MaskColors may be specified.
	MaskColors []uint16

	// SMask (optional; PDF 1.4) is a subsidiary image XObject defining a
	// soft-mask image for transparency effects.
	SMask *SoftMask

	// SMaskInData (optional for JPXDecode; PDF 1.5) specifies how soft-mask
	// information encoded with image samples should be used:
	// 0 = ignore encoded soft-mask info (default)
	// 1 = image data includes encoded soft-mask values
	// 2 = image data includes premultiplied opacity channel
	SMaskInData int

	// Interpolate indicates whether image interpolation should be performed by
	// a PDF processor.
	Interpolate bool

	// Alternates (optional) is an array of alternate image dictionaries for this image.
	Alternates []*Dict

	// OptionalContent (optional) allows to control the visibility of the image.
	OptionalContent oc.Conditional

	// Intent (optional) is the name of a color rendering intent to be used in
	// rendering the image.
	Intent graphics.RenderingIntent

	// StructParent (required if the image is a structural content item)
	// is the integer key of the image's entry in the structural parent tree.
	StructParent optional.UInt

	// Metadata (optional) is a metadata stream containing metadata for the image.
	Metadata *metadata.Stream

	// AssociatedFiles (optional; PDF 2.0) is an array of files associated with
	// the image. The relationship that the associated files have to the
	// XObject is supplied by the Specification.AFRelationship field.
	//
	// This corresponds to the AF entry in the image dictionary.
	AssociatedFiles []*file.Specification

	// Measure (optional; PDF 2.0) specifies the scale and units that apply to
	// the image.
	Measure measure.Measure

	// PtData (optional; PDF 2.0) contains extended geospatial point data.
	PtData *measure.PtData

	// WebCaptureID (optional) is the digital identifier of the image's parent
	// Web Capture content set.
	//
	// This corresponds to the /ID entry in the image mask dictionary.
	WebCaptureID *webcapture.Identifier

	// Name is deprecated and should be left empty.
	// Only used in PDF 1.0 where it was the name used to reference the image
	// mask from within content streams.
	Name pdf.Name
}

type Indexed struct {
	Pix        []uint8
	Width      int
	Height     int
	ColorSpace color.Space
}

type Mask struct {
	// Width is the width of the image mask in pixels.
	Width int

	// Height is the height of the image mask in pixels.
	Height int

	// Inverted indicates the meaning of individual bits in the image data:
	//   - false: 0=opaque and 1=transparent
	//   - true: 1=opaque and 0=transparent
	Inverted bool

	// WriteData is a function that writes the mask data to the provided writer.
	// The data should be written as a continuous bit stream, with each row
	// starting at a new byte boundary. 0 = opaque, 1 = transparent.
	WriteData func(io.Writer) error

	// Interpolate enables edge smoothing for the mask to reduce jagged
	// appearance in low-resolution stencil masks.
	Interpolate bool

	// Alternates (optional) is an array of alternate image dictionaries for this mask.
	Alternates []*Mask

	// OptionalContent (optional) allows to control the visibility of the mask.
	OptionalContent oc.Conditional

	// StructParent (required if the image mask is a structural content item)
	// is the integer key of the image mask's entry in the structural parent tree.
	StructParent optional.UInt

	// Metadata (optional) is a metadata stream containing metadata for the image.
	Metadata *metadata.Stream

	// AssociatedFiles (optional; PDF 2.0) is an array of files associated with
	// the mask. The relationship that the associated files have to the
	// XObject is supplied by the Specification.AFRelationship field.
	//
	// This corresponds to the AF entry in the image mask dictionary.
	AssociatedFiles []*file.Specification

	// Measure (optional; PDF 2.0) specifies the scale and units which apply to
	// the mask.
	Measure measure.Measure

	// PtData (optional; PDF 2.0) contains extended geospatial point data.
	PtData *measure.PtData

	// WebCaptureID (optional) is the digital identifier of the image's parent
	// Web Capture content set.
	//
	// This corresponds to the /ID entry in the image mask dictionary.
	WebCaptureID *webcapture.Identifier

	// Name is deprecated and should be left empty.
	// Only used in PDF 1.0 where it was the name used to reference the image
	// from within content streams.
	Name pdf.Name
}

type PixelRow struct {
	// contains filtered or unexported fields
}

type SoftMask struct {
	// Width is the width of the soft mask in pixels.
	// If Matte is present, this must match the parent image width.
	Width int

	// Height is the height of the soft mask in pixels.
	// If Matte is present, this must match the parent image height.
	Height int

	// BitsPerComponent is the number of bits used to represent each grayscale
	// component. The value must be 1, 2, 4, 8, or 16.
	BitsPerComponent int

	// Decode (optional) is an array of numbers describing how to map mask
	// samples into the range 0.0 to 1.0. If present, the array must contain
	// exactly 2 values [Dmin, Dmax]. Default: [0.0, 1.0] which maps 0 to
	// transparent, max to opaque.
	Decode []float64

	// WriteData is a function that writes the grayscale mask data to the
	// provided writer. The data should be written row by row, with each row
	// containing Width samples, each sample using BitsPerComponent bits.
	WriteData func(io.Writer) error

	// Interpolate indicates whether mask interpolation should be performed by
	// a PDF processor to reduce pixelation in low-resolution masks.
	Interpolate bool

	// Matte (optional) specifies the matte color used for pre-blended image
	// data. The array must contain n values where n is the number of
	// components in the parent image's color space. When present, the parent
	// image data has been pre-multiplied with this matte color using the soft
	// mask as the alpha channel.
	Matte []float64
}