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Font refactor #52

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Oct 5, 2024
Merged

Font refactor #52

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26 changes: 5 additions & 21 deletions lib/pdf/external_font.ex
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
defmodule Pdf.ExternalFont do
@moduledoc false
@derive {Inspect, only: [:name, :family_name, :weight, :italic_angle]}
defstruct name: nil,
font_file: nil,
dictionary: nil,
Expand Down Expand Up @@ -49,8 +50,6 @@ defmodule Pdf.ExternalFont do

%__MODULE__{
name: font_metrics.name,
font_file: font_file,
dictionary: font_file_dictionary(part1, part2, part3),
full_name: font_metrics.full_name,
family_name: font_metrics.family_name,
weight: font_metrics.weight,
Expand All @@ -65,9 +64,11 @@ defmodule Pdf.ExternalFont do
fixed_pitch: font_metrics.fixed_pitch,
bbox: font_metrics.bbox,
widths: widths,
glyph_widths: map_widths(font_metrics),
glyph_widths: Metrics.map_widths(font_metrics),
glyphs: font_metrics.glyphs,
kern_pairs: font_metrics.kern_pairs
kern_pairs: font_metrics.kern_pairs,
font_file: font_file,
dictionary: font_file_dictionary(part1, part2, part3)
}
end

Expand Down Expand Up @@ -113,23 +114,6 @@ defmodule Pdf.ExternalFont do
byte_size(to_iolist(font) |> Enum.join())
end

defp map_widths(font) do
Pdf.Encoding.WinAnsi.characters()
|> Enum.map(fn {_, char, name} ->
width =
case font.glyphs[name] do
nil ->
0

%{width: width} ->
width
end

{char, width}
end)
|> Map.new()
end

@doc """
Returns the width of the specific character

Expand Down
210 changes: 56 additions & 154 deletions lib/pdf/font.ex
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Original file line number Diff line number Diff line change
Expand Up @@ -2,159 +2,28 @@ defmodule Pdf.Font do
@moduledoc false

import Pdf.Utils
alias Pdf.Font.Metrics
# alias Pdf.Font.Metrics
alias Pdf.{Array, Dictionary, Font}

font_metrics =
Path.join(__DIR__, "../../fonts/*.afm")
|> Path.wildcard()
|> Enum.map(fn afm_file ->
afm_file
|> File.stream!()
|> Enum.reduce(%Metrics{}, fn line, metrics ->
Metrics.process_line(String.replace_suffix(line, "\n", ""), metrics)
end)
end)

font_metrics
|> Enum.each(fn metrics ->
font_module = String.to_atom("Elixir.Pdf.Font.#{String.replace(metrics.name, "-", "")}")

defmodule font_module do
@moduledoc false
@doc "The name of the font"
def name, do: unquote(metrics.name)
@doc "The full name of the font"
def full_name, do: unquote(metrics.full_name)
@doc "The font family of the font"
def family_name, do: unquote(metrics.family_name)
@doc "The font weight"
def weight, do: unquote(metrics.weight)
@doc "The font italic angle"
def italic_angle, do: unquote(metrics.italic_angle)
@doc "The font encoding"
def encoding, do: unquote(metrics.encoding)
@doc "The first character defined in `widths/0`"
def first_char, do: unquote(metrics.first_char)
@doc "The last character defined in `widths/0`"
def last_char, do: unquote(metrics.last_char)
@doc "The font ascender"
def ascender, do: unquote(metrics.ascender || 0)
@doc "The font descender"
def descender, do: unquote(metrics.descender || 0)
@doc "The font cap height"
def cap_height, do: unquote(metrics.cap_height)
@doc "The font x-height"
def x_height, do: unquote(metrics.x_height)
@doc "The font bbox"
def bbox, do: unquote(Macro.escape(metrics.bbox))

{_llx, lly, _urx, ury} = metrics.bbox

def line_gap,
do: unquote(ury - lly - ((metrics.ascender || 0) + (metrics.descender || 0)))

@doc """
Returns the character widths of characters beginning from `first_char/0`
"""
def widths, do: unquote(Metrics.widths(metrics))

@doc """
Returns the width of the specific character

Examples:

iex> #{inspect(__MODULE__)}.width("A")
123
"""
def width(char_code)

Pdf.Encoding.WinAnsi.characters()
|> Enum.each(fn {char_code, _, name} ->
case metrics.glyphs[name] do
nil ->
def width(unquote(char_code)), do: 0

%{width: width} ->
def width(unquote(char_code)), do: unquote(width)
end
end)

def kern_text(""), do: [""]

metrics.kern_pairs
|> Enum.each(fn {first, second, amount} ->
def kern_text(<<unquote(first)::integer, unquote(second)::integer, rest::binary>>) do
[
<<unquote(first)>>,
unquote(-amount) | kern_text(<<unquote(second)::integer, rest::binary>>)
]
end
end)

def kern_text(<<first::integer, second::integer, rest::binary>>) do
[head | tail] = kern_text(<<second::integer, rest::binary>>)
[<<first::integer, head::binary>> | tail]
end

def kern_text(<<_::integer>> = char), do: [char]
end
end)

@doc ~S"""
Returns the font module for the named font

# Example:

iex> Pdf.Font.lookup("Helvetica-BoldOblique")
Pdf.Font.HelveticaBoldOblique
"""
def lookup(name, opts \\ [])

font_metrics
|> Enum.each(fn metrics ->
font_module = String.to_atom("Elixir.Pdf.Font.#{String.replace(metrics.name, "-", "")}")

if metrics.weight == :bold and metrics.italic_angle == 0 do
def lookup(unquote(metrics.family_name), bold: true), do: unquote(font_module)

def lookup(unquote(metrics.family_name), bold: true, italic: false),
do: unquote(font_module)

def lookup(unquote(metrics.family_name), italic: false, bold: true),
do: unquote(font_module)
end

if metrics.weight == :bold and metrics.italic_angle != 0 do
def lookup(unquote(metrics.family_name), bold: true, italic: true), do: unquote(font_module)
def lookup(unquote(metrics.family_name), italic: true, bold: true), do: unquote(font_module)
end

if metrics.weight != :bold and metrics.italic_angle == 0 do
def lookup(unquote(metrics.family_name), italic: false, bold: false),
do: unquote(font_module)

def lookup(unquote(metrics.family_name), bold: false, italic: false),
do: unquote(font_module)

def lookup(unquote(metrics.family_name), []),
do: unquote(font_module)
end

if metrics.weight != :bold and metrics.italic_angle != 0 do
def lookup(unquote(metrics.family_name), italic: true), do: unquote(font_module)

def lookup(unquote(metrics.family_name), bold: false, italic: true),
do: unquote(font_module)

def lookup(unquote(metrics.family_name), italic: true, bold: false),
do: unquote(font_module)
end

# def lookup(unquote(metrics.name), []), do: unquote(font_module)
end)

def lookup(_name, _opts), do: nil
@derive {Inspect, only: [:name, :family_name, :weight, :italic_angle]}
defstruct name: nil,
full_name: nil,
family_name: nil,
weight: nil,
italic_angle: nil,
encoding: nil,
first_char: nil,
last_char: nil,
ascender: nil,
descender: nil,
cap_height: nil,
x_height: nil,
fixed_pitch: nil,
bbox: nil,
widths: nil,
glyph_widths: nil,
glyphs: nil,
kern_pairs: nil

def to_dictionary(font, id) do
Dictionary.new()
Expand All @@ -176,12 +45,12 @@ defmodule Pdf.Font do
iex> Font.width(font, "A")
123
"""
def width(%Pdf.ExternalFont{} = font, char_code) do
Pdf.ExternalFont.width(font, char_code)
def width(font, <<char_code::integer>> = str) when is_binary(str) do
width(font, char_code)
end

def width(font, char_code) do
font.width(char_code)
font.glyph_widths[char_code] || 0
end

@doc ~S"""
Expand Down Expand Up @@ -230,11 +99,44 @@ defmodule Pdf.Font do

def kern_text(_font, ""), do: [""]

def kern_text(font, <<first::integer, second::integer, rest::binary>>) do
font.kern_pairs
|> Enum.find(fn {f, s, _amount} -> f == first && s == second end)
|> case do
{f, _s, amount} ->
[<<f>>, -amount | kern_text(font, <<second::integer, rest::binary>>)]

nil ->
[head | tail] = kern_text(font, <<second::integer, rest::binary>>)
[<<first::integer, head::binary>> | tail]
end
end

def kern_text(_font, <<_::integer>> = char), do: [char]

def kern_text(_font, ""), do: [""]

def kern_text(%Pdf.ExternalFont{} = font, text) do
Pdf.ExternalFont.kern_text(font, text)
end

def kern_text(font, text) do
font.kern_text(text)
end

@doc """
Lookup a font by family name and attributes [bold: true, italic: true]
"""
def matches_attributes(font, attrs) do
bold = Keyword.get(attrs, :bold, false)
italic = Keyword.get(attrs, :italic, false)

cond do
bold && !italic && font.weight == :bold && font.italic_angle == 0 -> true
bold && italic && font.weight == :bold && font.italic_angle != 0 -> true
!bold && !italic && font.weight != :bold && font.italic_angle == 0 -> true
!bold && italic && font.weight != :bold && font.italic_angle != 0 -> true
true -> false
end
end
end
17 changes: 17 additions & 0 deletions lib/pdf/font/metrics.ex
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,23 @@ defmodule Pdf.Font.Metrics do
end)
end

def map_widths(font) do
Pdf.Encoding.WinAnsi.characters()
|> Enum.map(fn {_, char, name} ->
width =
case font.glyphs[name] do
nil ->
0

%{width: width} ->
width
end

{char, width}
end)
|> Map.new()
end

def process_line(<<"FontName ", data::binary>>, metrics), do: %{metrics | name: data}
def process_line(<<"FullName ", data::binary>>, metrics), do: %{metrics | full_name: data}
def process_line(<<"FamilyName ", data::binary>>, metrics), do: %{metrics | family_name: data}
Expand Down
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