Class: PSD::Image

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Includes:
Export::PNG, PSD::ImageFormat::RAW, PSD::ImageFormat::RLE, PSD::ImageMode::CMYK, PSD::ImageMode::Greyscale, PSD::ImageMode::RGB
Defined in:
lib/psd/image.rb,
lib/psd/image_exports/png.rb

Overview

Parses the full preview image at the end of the PSD document.

Direct Known Subclasses

ChannelImage

Defined Under Namespace

Modules: Export

Constant Summary collapse

COMPRESSIONS =

All of the possible compression formats Photoshop uses.

[
  'Raw',
  'RLE',
  'ZIP',
  'ZIPPrediction'
].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Export::PNG

#save_as_png, #to_png

Constructor Details

#initialize(file, header) ⇒ Image

Store a reference to the file and the header. We also do a few simple calculations to figure out the number of pixels in the image and the length of each channel.



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# File 'lib/psd/image.rb', line 35

def initialize(file, header)
  @file = file
  @header = header

  @num_pixels = width * height
  @num_pixels *= 2 if depth == 16

  calculate_length
  set_channels_info

  @channel_data = []
  @pixel_data = []
  @opacity = 1.0
  @has_mask = false

  @start_pos = @file.tell
  @end_pos = @start_pos + @length

  PSD.logger.debug "Image: #{width}x#{height}, length = #{@length}, mode = #{@header.mode_name}, position = #{@start_pos}"
end

Instance Attribute Details

#has_mask ⇒ Object (readonly) Also known as: has_mask?

Returns the value of attribute has_mask.



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# File 'lib/psd/image.rb', line 19

def has_mask
  @has_mask
end

#opacity ⇒ Object (readonly)

Returns the value of attribute opacity.



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# File 'lib/psd/image.rb', line 19

def opacity
  @opacity
end

#pixel_data ⇒ Object (readonly)

Returns the value of attribute pixel_data.



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# File 'lib/psd/image.rb', line 19

def pixel_data
  @pixel_data
end

Instance Method Details

#parse ⇒ Object

Begins parsing the image by first figuring out the compression format used, and then by reading the image data.



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# File 'lib/psd/image.rb', line 58

def parse
  @compression = parse_compression!

  # ZIP not implemented
  if [2, 3].include?(@compression)
    PSD.logger.debug "Warning: ZIP image compression not supported yet. Skipping."
    @file.seek @end_pos and return
  end

  PSD.logger.debug "Compression: id = #{@compression}, name = #{COMPRESSIONS[@compression]}"

  parse_image_data!

  return self
end