104 lines
3.1 KiB
Ruby
104 lines
3.1 KiB
Ruby
# frozen_string_literal: true
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require_relative '../table'
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module TTFunk
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class Table
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# Standard Bitmap Graphics (`sbix`) table.
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class Sbix < Table
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# Table version.
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# @return [Integer]
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attr_reader :version
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# Flags.
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# @return [Integer]
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attr_reader :flags
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# Number of bitmap strikes.
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# @return [Integer]
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attr_reader :num_strikes
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# Strikes.
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# @return [Array<Hash>]
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attr_reader :strikes
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# Bitmap Data.
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#
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# @!attribute [rw] x
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# The horizontal (x-axis) position of the left edge of the bitmap
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# graphic in relation to the glyph design space origin.
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# @!attribute [rw] y
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# The vertical (y-axis) position of the bottom edge of the bitmap
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# graphic in relation to the glyph design space origin.
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# @!attribute [rw] type
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# Indicates the format of the embedded graphic data: one of `jpg `,
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# `png `, `tiff`, or the special format `dupe`.
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# @!attribute [rw] data
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# The actual embedded graphic data.
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# @!attribute [rw] ppem
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# The PPEM size for which this strike was designed.
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# @!attribute [rw] resolution
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# The device pixel density (in PPI) for which this strike was designed.
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BitmapData = Struct.new(:x, :y, :type, :data, :ppem, :resolution)
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# Get bitmap for glyph strike.
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#
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# @param glyph_id [Integer]
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# @param strike_index [Integer]
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# @return [BitmapData]
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def bitmap_data_for(glyph_id, strike_index)
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strike = strikes[strike_index]
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return if strike.nil?
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glyph_offset = strike[:glyph_data_offset][glyph_id]
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next_glyph_offset = strike[:glyph_data_offset][glyph_id + 1]
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if glyph_offset && next_glyph_offset
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bytes = next_glyph_offset - glyph_offset
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if bytes.positive?
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parse_from(offset + strike[:offset] + glyph_offset) {
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x, y, type = read(8, 's2A4')
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data = StringIO.new(io.read(bytes - 8))
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BitmapData.new(x, y, type, data, strike[:ppem], strike[:resolution])
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}
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end
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end
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end
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# Get all bitmaps for glyph.
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#
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# @param glyph_id [Integer]
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# @return [Array<BitmapData>]
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def all_bitmap_data_for(glyph_id)
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strikes.each_index.filter_map { |strike_index|
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bitmap_data_for(glyph_id, strike_index)
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}
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end
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private
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def parse!
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@version, @flags, @num_strikes = read(8, 'n2N')
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strike_offsets = Array.new(num_strikes) { read(4, 'N').first }
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@strikes =
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strike_offsets.map { |strike_offset|
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parse_from(offset + strike_offset) {
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ppem, resolution = read(4, 'n2')
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data_offsets =
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Array.new(file.maximum_profile.num_glyphs + 1) {
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read(4, 'N').first
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}
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{
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ppem: ppem,
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resolution: resolution,
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offset: strike_offset,
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glyph_data_offset: data_offsets,
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}
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}
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}
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end
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end
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end
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end
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