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# frozen_string_literal: true
# Spec'ing the PNG class. Not complete yet - still needs to check the
# contents of palette and transparency to ensure they're correct.
# Need to find files that have these sections first.
#
# see http://www.w3.org/TR/PNG/ for a detailed description of the PNG spec,
# particuarly Table 11.1 for the different color types
require 'spec_helper'
describe Prawn::Images::PNG do
describe 'When making a pdf file with png images' do
image_dir = "#{Prawn::DATADIR}/images"
images = [
#['Type 0', "#{image_dir}/web-links.png"],
#['Type 0 with transparency', "#{image_dir}/ruport_type0.png"],
#['Type 2', "#{image_dir}/ruport.png"],
#['Type 2 with transparency', "#{image_dir}/arrow2.png"],
['Type 3', "#{image_dir}/indexed_color.png"],
['Type 3 with transparency', "#{image_dir}/indexed_transparency.png"],
#['Type 4', "#{image_dir}/page_white_text.png"],
#['Type 6', "#{image_dir}/dice.png"],
#['Type 6 in 16bit', "#{image_dir}/16bit.png"]
]
images.each do |header, file|
describe "and the image is #{header}" do
it 'does not error' do
expect do
Prawn::Document.generate("#{header}.pdf", page_size: 'A5') do
fill_color '00FF00'
fill_rectangle bounds.top_left, bounds.width, bounds.height
text header
image file, at: [50, 450]
end
end.to_not raise_error
end
end
end
end
describe 'When reading a greyscale PNG file (color type 0)' do
let(:data_filename) { "#{Prawn::DATADIR}/images/web-links.dat" }
let(:img_data) { File.binread("#{Prawn::DATADIR}/images/web-links.png") }
xit 'reads the attributes from the header chunk correctly' do
png = described_class.new(img_data)
expect(png.width).to eq(21)
expect(png.height).to eq(14)
expect(png.bits).to eq(8)
expect(png.color_type).to eq(0)
expect(png.compression_method).to eq(0)
expect(png.filter_method).to eq(0)
expect(png.interlace_method).to eq(0)
end
xit 'reads the image data chunk correctly' do
png = described_class.new(img_data)
data = Zlib::Inflate.inflate(File.binread(data_filename))
expect(png.img_data).to eq(data)
end
end
describe 'When reading a greyscale PNG with transparency (color type 0)' do
let(:img_data) { File.binread("#{Prawn::DATADIR}/images/ruport_type0.png") }
# In a greyscale type 0 PNG image, the tRNS chunk should contain a single
# value that indicates the color that should be interpreted as transparent.
#
# http://www.w3.org/TR/PNG/#11tRNS
xit 'reads the tRNS chunk correctly' do
png = described_class.new(img_data)
expect(png.transparency[:grayscale]).to eq(255)
end
end
describe 'When reading an RGB PNG file (color type 2)' do
let(:data_filename) { "#{Prawn::DATADIR}/images/ruport_data.dat" }
let(:img_data) { File.binread("#{Prawn::DATADIR}/images/ruport.png") }
xit 'reads the attributes from the header chunk correctly' do
png = described_class.new(img_data)
expect(png.width).to eq(258)
expect(png.height).to eq(105)
expect(png.bits).to eq(8)
expect(png.color_type).to eq(2)
expect(png.compression_method).to eq(0)
expect(png.filter_method).to eq(0)
expect(png.interlace_method).to eq(0)
end
xit 'reads the image data chunk correctly' do
png = described_class.new(img_data)
data = Zlib::Inflate.inflate(File.binread(data_filename))
expect(png.img_data).to eq(data)
end
end
describe 'When reading an RGB PNG file with transparency (color type 2)' do
let(:img_data) { File.binread("#{Prawn::DATADIR}/images/arrow2.png") }
# In a RGB type 2 PNG image, the tRNS chunk should contain a single RGB
# value that indicates the color that should be interpreted as transparent.
# In this case it's green.
#
# http://www.w3.org/TR/PNG/#11tRNS
xit 'reads the tRNS chunk correctly' do
png = described_class.new(img_data)
expect(png.transparency[:rgb]).to eq([0, 255, 0])
end
end
describe 'When reading an indexed color PNG file with transparency '\
'(color type 3)' do
let(:filename) { "#{Prawn::DATADIR}/images/indexed_transparency.png" }
let(:color_filename) do
"#{Prawn::DATADIR}/images/indexed_transparency_color.dat"
end
let(:transparency_filename) do
"#{Prawn::DATADIR}/images/indexed_transparency_alpha.dat"
end
let(:img_data) { File.binread(filename) }
let(:png) { described_class.new(img_data) }
it 'reads the attributes from the header chunk correctly' do
expect(png.width).to eq(200)
expect(png.height).to eq(200)
expect(png.bits).to eq(8)
expect(png.color_type).to eq(3)
expect(png.compression_method).to eq(0)
expect(png.filter_method).to eq(0)
expect(png.interlace_method).to eq(0)
end
it 'reads the image data correctly' do
data = Zlib::Inflate.inflate(File.binread(color_filename))
expect(png.img_data).to eq(data)
end
it 'reads the image transparency correctly' do
png.split_alpha_channel!
data = Zlib::Inflate.inflate(File.binread(transparency_filename))
expect(png.alpha_channel).to eq(data)
end
end
describe 'When reading an indexed color PNG file (color type 3)' do
let(:data_filename) { "#{Prawn::DATADIR}/images/indexed_color.dat" }
let(:img_data) do
File.binread("#{Prawn::DATADIR}/images/indexed_color.png")
end
xit 'reads the attributes from the header chunk correctly' do
png = described_class.new(img_data)
expect(png.width).to eq(150)
expect(png.height).to eq(200)
expect(png.bits).to eq(8)
expect(png.color_type).to eq(3)
expect(png.compression_method).to eq(0)
expect(png.filter_method).to eq(0)
expect(png.interlace_method).to eq(0)
end
xit 'reads the image data chunk correctly' do
png = described_class.new(img_data)
data = Zlib::Inflate.inflate(File.binread(data_filename))
expect(png.img_data).to eq(data)
end
end
describe 'When reading a greyscale+alpha PNG file (color type 4)' do
let(:color_data_filename) do
"#{Prawn::DATADIR}/images/page_white_text.color"
end
let(:alpha_data_filename) do
"#{Prawn::DATADIR}/images/page_white_text.alpha"
end
let(:img_data) do
File.binread("#{Prawn::DATADIR}/images/page_white_text.png")
end
xit 'reads the attributes from the header chunk correctly' do
png = described_class.new(img_data)
expect(png.width).to eq(16)
expect(png.height).to eq(16)
expect(png.bits).to eq(8)
expect(png.color_type).to eq(4)
expect(png.compression_method).to eq(0)
expect(png.filter_method).to eq(0)
expect(png.interlace_method).to eq(0)
end
xit 'correctly returns the raw image data (with no alpha channel) from '\
'the image data chunk' do
png = described_class.new(img_data)
png.split_alpha_channel!
data = File.binread(color_data_filename)
expect(png.img_data).to eq(data)
end
xit 'correctly extracts the alpha channel data from the image data chunk' do
png = described_class.new(img_data)
png.split_alpha_channel!
data = File.binread(alpha_data_filename)
expect(png.alpha_channel).to eq(data)
end
end
describe 'When reading an RGB+alpha PNG file (color type 6)' do
let(:color_data_filename) { "#{Prawn::DATADIR}/images/dice.color" }
let(:alpha_data_filename) { "#{Prawn::DATADIR}/images/dice.alpha" }
let(:img_data) { File.binread("#{Prawn::DATADIR}/images/dice.png") }
xit 'reads the attributes from the header chunk correctly' do
png = described_class.new(img_data)
expect(png.width).to eq(320)
expect(png.height).to eq(240)
expect(png.bits).to eq(8)
expect(png.color_type).to eq(6)
expect(png.compression_method).to eq(0)
expect(png.filter_method).to eq(0)
expect(png.interlace_method).to eq(0)
end
xit 'correctly returns the raw image data (with no alpha channel) from '\
'the image data chunk' do
png = described_class.new(img_data)
png.split_alpha_channel!
data = File.binread(color_data_filename)
expect(png.img_data).to eq(data)
end
xit 'correctly extracts the alpha channel data from the image data chunk' do
png = described_class.new(img_data)
png.split_alpha_channel!
data = File.binread(alpha_data_filename)
expect(png.alpha_channel).to eq(data)
end
end
describe 'When reading a 16bit RGB+alpha PNG file (color type 6)' do
let(:color_data_filename) { "#{Prawn::DATADIR}/images/16bit.color" }
# alpha channel truncated to 8-bit
let(:alpha_data_filename) { "#{Prawn::DATADIR}/images/16bit.alpha" }
let(:img_data) { File.binread("#{Prawn::DATADIR}/images/16bit.png") }
xit 'reads the attributes from the header chunk correctly' do
png = described_class.new(img_data)
expect(png.width).to eq(32)
expect(png.height).to eq(32)
expect(png.bits).to eq(16)
expect(png.color_type).to eq(6)
expect(png.compression_method).to eq(0)
expect(png.filter_method).to eq(0)
expect(png.interlace_method).to eq(0)
end
xit 'correctly returns the raw image data (with no alpha channel) from '\
'the image data chunk' do
png = described_class.new(img_data)
png.split_alpha_channel!
data = File.binread(color_data_filename)
expect(png.img_data).to eq(data)
end
xit 'correctly extracts the alpha channel data from the image data chunk' do
png = described_class.new(img_data)
png.split_alpha_channel!
data = File.binread(alpha_data_filename)
expect(png.alpha_channel).to eq(data)
end
end
end
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