@ -7,7 +7,35 @@ local Freetype = require("ffi/freetype")
local Screen = require ( " device " ) . screen
local logger = require ( " logger " )
-- Known regular (and italic) fonts with an available bold font file
local _bold_font_variant = { }
_bold_font_variant [ " NotoSans-Regular.ttf " ] = " NotoSans-Bold.ttf "
_bold_font_variant [ " NotoSans-Italic.ttf " ] = " NotoSans-BoldItalic.ttf "
_bold_font_variant [ " NotoSansArabicUI-Regular.ttf " ] = " NotoSansArabicUI-Bold.ttf "
_bold_font_variant [ " NotoSerif-Regular.ttf " ] = " NotoSerif-Bold.ttf "
_bold_font_variant [ " NotoSerif-Italic.ttf " ] = " NotoSerif-BoldItalic.ttf "
-- Build the reverse mapping, so we can know a font is bold
local _regular_font_variant = { }
for regular , bold in pairs ( _bold_font_variant ) do
_regular_font_variant [ bold ] = regular
end
local Font = {
-- Make these available in the Font object, so other code
-- can complete them if needed.
bold_font_variant = _bold_font_variant ,
regular_font_variant = _regular_font_variant ,
-- Allow globally not promoting fonts to their bold variants
-- (and use thiner and narrower synthetized bold instead).
use_bold_font_for_bold = G_reader_settings : nilOrTrue ( " use_bold_font_for_bold " ) ,
-- Widgets can provide "bold = Font.FORCE_SYNTHETIZED_BOLD" instead
-- of "bold = true" to explicitely request synthetized bold, which,
-- with XText, makes a bold string the same width as itself non-bold.
FORCE_SYNTHETIZED_BOLD = " FORCE_SYNTHETIZED_BOLD " ,
fontmap = {
-- default font for menu contents
cfont = " NotoSans-Regular.ttf " ,
@ -74,6 +102,8 @@ local Font = {
x_smallinfofont = 20 ,
xx_smallinfofont = 18 ,
} ,
-- This fallback fonts list should only contain
-- regular weight (non bold) font files.
fallbacks = {
[ 1 ] = " NotoSans-Regular.ttf " ,
[ 2 ] = " NotoSansCJKsc-Regular.otf " ,
@ -87,39 +117,89 @@ local Font = {
faces = { } ,
}
-- Helper functions with explicite names around
-- bold/regular_font_variant tables
function Font : hasBoldVariant ( name )
return self.bold_font_variant [ name ] and true or false
end
function Font : getBoldVariantName ( name )
return self.bold_font_variant [ name ]
end
function Font : isRealBoldFont ( name )
return self.regular_font_variant [ name ] and true or false
end
function Font : getRegularVariantName ( name )
return self.regular_font_variant [ name ] or name
end
-- Synthetized bold strength can be tuned:
-- local bold_strength_factor = 1 -- really too bold
-- local bold_strength_factor = 1/2 -- bold enough
local bold_strength_factor = 3 / 8 -- as crengine, lighter
-- Add some properties to a face object as needed
local _completeFaceProperties = function ( face_obj )
if not face_obj.embolden_half_strength then
-- Cache this value in case we use bold, to avoid recomputation
face_obj.embolden_half_strength = face_obj.ftface : getEmboldenHalfStrength ( bold_strength_factor )
end
end
-- Callback to be used by libkoreader-xtext.so to get Freetype
-- instantiated fallback fonts when needed for shaping text
-- (Beware: any error in this code won't be noticed when this
-- is called from the C module...)
local _getFallbackFont = function ( face_obj , num )
if not num or num == 0 then -- return the main font
if not face_obj.embolden_half_strength then
-- cache this value in case we use bold, to avoid recomputation
face_obj.embolden_half_strength = face_obj.ftface : getEmboldenHalfStrength ( bold_strength_factor )
end
_completeFaceProperties ( face_obj )
return face_obj
end
if not face_obj.fallbacks then
face_obj.fallbacks = { }
end
if face_obj.fallbacks [ num ] ~= nil then
if face_obj.fallbacks [ num ] ~= nil then -- (false means: no more fallback font)
return face_obj.fallbacks [ num ]
end
local next_num = # face_obj.fallbacks + 1
local cur_num = 0
local realname = face_obj.realname
if face_obj.is_real_bold then
-- Get the regular name, to skip it from Font.fallbacks
realname = Font : getRegularVariantName ( realname )
end
for index , fontname in pairs ( Font.fallbacks ) do
if fontname ~= face_obj.realname then -- Skip base one if among fallbacks
if fontname ~= realname then -- Skip base one if among fallbacks
-- If main font is a real bold, or if it's not but we want bold,
-- get the bold variant of the fallback if one exists.
-- But if one exists, use the regular variant as an additional
-- fallback, drawn with synthetized bold (often, bold fonts
-- have less glyphs than their regular counterpart).
if face_obj.is_real_bold or face_obj.wants_bold == true then
-- (not if wants_bold==Font.FORCE_SYNTHETIZED_BOLD)
local bold_variant_name = Font : getBoldVariantName ( fontname )
if bold_variant_name then
-- There is a bold variant of that fallback font, that we can use
local fb_face = Font : getFace ( bold_variant_name , face_obj.orig_size )
if fb_face ~= nil then -- valid font
cur_num = cur_num + 1
if cur_num == next_num then
_completeFaceProperties ( fb_face )
face_obj.fallbacks [ next_num ] = fb_face
return fb_face
end
-- otherwise, go on with the regular variant
end
end
end
local fb_face = Font : getFace ( fontname , face_obj.orig_size )
if fb_face ~= nil then -- valid font
cur_num = cur_num + 1
if cur_num == next_num then
_completeFaceProperties ( fb_face )
face_obj.fallbacks [ next_num ] = fb_face
if not fb_face.embolden_half_strength then
fb_face.embolden_half_strength = fb_face.ftface : getEmboldenHalfStrength ( bold_strength_factor )
end
return fb_face
end
end
@ -143,14 +223,21 @@ function Font:getFace(font, size)
local orig_size = size
size = Screen : scaleBySize ( size )
local hash = font .. size
local realname = self.fontmap [ font ]
if not realname then
realname = font
end
-- Avoid emboldening already bold fonts
local is_real_bold = self : isRealBoldFont ( realname )
-- Make a hash from the realname (many fonts in our fontmap use
-- the same font file: have them share their glyphs cache)
local hash = realname .. size
local face_obj = self.faces [ hash ]
-- build face if not found
if not face_obj then
local realname = self.fontmap [ font ]
if not realname then
realname = font
end
local builtin_font_location = FontList.fontdir .. " / " .. realname
local ok , face = pcall ( Freetype.newFace , builtin_font_location , size )
@ -187,6 +274,7 @@ function Font:getFace(font, size)
orig_size = orig_size ,
ftface = face ,
hash = hash ,
is_real_bold = is_real_bold ,
}
self.faces [ hash ] = face_obj
@ -214,4 +302,84 @@ function Font:getFace(font, size)
return face_obj
end
--- Returns an alternative face instance to be used for measuring
-- and drawing (in most cases, the one provided untouched)
--
-- If 'bold' is true, or if 'face' is a real bold face, we may need to
-- use an alternative instance of the font, with possibly the associated
-- real bold font, and/or with tweaks so fallback fonts are rendered
-- bold too, without affecting the regular 'face'.
-- (This function should only be used by TextWidget and TextBoxWidget.
-- Other widgets should not use it, and neither _getFallbackFont()
-- which will do its own processing.)
--
-- @tparam ui.font.FontFaceObj provided face font face
-- @bool bold whether bold is requested
-- @treturn ui.font.FontFaceObj face face to use for drawing
-- @treturn bool bold adjusted bold properties
function Font : getAdjustedFace ( face , bold )
if face.is_real_bold then
-- No adjustment needed: main real bold font will ensure
-- fallback fonts use their associated bold font or
-- get synthetized bold - whether bold is requested or not
-- (Set returned bold to true, to force synthetized bold
-- on fallback fonts with no associated real bold)
-- (Drop bold=FORCE_SYNTHETIZED_BOLD and use 'true' if
-- we were given a real bold font.)
return face , true
end
if not bold then
-- No adjustment needed: regular main font, and regular
-- fallback fonts untouched.
return face , false
end
-- We have bold requested, and a regular/non-bold font.
if not self.use_bold_font_for_bold then
-- If promotion to real bold is not wished, force synth bold
bold = Font.FORCE_SYNTHETIZED_BOLD
end
if bold ~= Font.FORCE_SYNTHETIZED_BOLD then
-- See if a bold font file exists for that regular font.
local bold_variant_name = self : getBoldVariantName ( face.realname )
if bold_variant_name then
face = Font : getFace ( bold_variant_name , face.orig_size )
-- It has is_real_bold=true: no adjustment needed
return face , true
end
end
-- Only the regular font is available, and bold requested:
-- we'll have synthetized bold - but _getFallbackFont() should
-- build a list of fallback fonts either synthetized, or possibly
-- using the bold variant of a regular fallback font.
-- We don't want to collide with the regular font face_obj.fallbacks
-- so let's make a shallow clone of this face_obj, and have it cached.
-- (Different hash if real bold accepted or not, as the fallback
-- fonts list may then be different.)
local hash = face.hash .. ( bold == Font.FORCE_SYNTHETIZED_BOLD and " synthbold " or " realbold " )
local face_obj = self.faces [ hash ]
if face_obj then
return face_obj , bold
end
face_obj = {
orig_font = face.orig_font ,
realname = face.realname ,
size = face.size ,
orig_size = face.orig_size ,
-- We can keep the same FT object and the same hash in this face_obj
-- (which is only used to identify cached glyphs, that we don't need
-- to distinguish as "bold" is appended when synthetized as bold)
ftface = face.ftface ,
hash = face.hash ,
hb_features = face.hb_features ,
is_real_bold = nil ,
wants_bold = bold , -- true or Font.FORCE_SYNTHETIZED_BOLD, used
-- to pick the appropritate fallback fonts
}
face_obj.getFallbackFont = function ( num )
return _getFallbackFont ( face_obj , num )
end
self.faces [ hash ] = face_obj
return face_obj , bold
end
return Font
poire-z
4 years ago
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