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path: root/support/make4ht/domfilters/make4ht-joincharacters.lua
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-rw-r--r--support/make4ht/domfilters/make4ht-joincharacters.lua113
1 files changed, 84 insertions, 29 deletions
diff --git a/support/make4ht/domfilters/make4ht-joincharacters.lua b/support/make4ht/domfilters/make4ht-joincharacters.lua
index 5830eae78e..4493aef023 100644
--- a/support/make4ht/domfilters/make4ht-joincharacters.lua
+++ b/support/make4ht/domfilters/make4ht-joincharacters.lua
@@ -3,14 +3,35 @@ local log = logging.new("joincharacters")
local charclasses = {
span=true,
mn = true,
- mi = true
}
+local function update_mathvariant(curr)
+ -- when we join several <mi> elements, they will be rendered incorrectly
+ -- we must set the mathvariant attribute
+ local parent = curr:get_parent()
+ -- set mathvariant only if it haven't been set by the parent element
+ if not parent:get_attribute("mathvariant") then
+ -- curr._attr = curr._attr or {}
+ local mathvariant = "italic"
+ -- the joined elements don't have attributes
+ curr._attr = curr._attr or {}
+ curr:set_attribute("mathvariant", mathvariant)
+ end
+end
+
+local table_count = function(tbl)
+ local tbl = tbl or {}
+ local i = 0
+ for k,v in pairs(tbl) do i = i + 1 end
+ return i
+end
+
+
local has_matching_attributes = function (el, next_el)
local el_attr = el._attr or {}
local next_attr = next_el._attr or {}
-- if the number of attributes doesn't match, elements don't match
- if #next_attr ~= #el_attr then return false end
+ if table_count(next_attr) ~= table_count(el_attr) then return false end
for k, v in pairs(el_attr) do
-- if any attribute doesn't match, elements don't match
if v~=next_attr[k] then return false end
@@ -18,6 +39,7 @@ local has_matching_attributes = function (el, next_el)
return true
end
+
local function join_characters(obj,par)
-- join adjanced span and similar elements inserted by
-- tex4ht to just one object.
@@ -25,45 +47,48 @@ local function join_characters(obj,par)
local options = get_filter_settings "joincharacters"
local charclasses = options.charclasses or par.charclasses or charclasses
-
- obj:traverse_elements(function(el)
- local get_name = function(curr)
- return string.lower(curr:get_element_name())
- end
- local get_class = function(next_el)
- return next_el:get_attribute("class") or next_el:get_attribute("mathvariant")
- end
- local is_span = function(next_el)
- return charclasses[get_name(next_el)]
+ local get_name = function(curr)
+ return string.lower(curr:get_element_name())
+ end
+ local get_class = function(next_el)
+ return next_el:get_attribute("class") or next_el:get_attribute("mathvariant")
+ end
+ local is_span = function(next_el)
+ return charclasses[get_name(next_el)]
+ end
+ local join_elements = function(el, next_el)
+ -- it the following element match, copy it's children to the current element
+ for _, child in ipairs(next_el:get_children()) do
+ el:add_child_node(child)
end
+ -- remove the next element
+ next_el:remove_node()
+ end
- local function get_next(curr, class)
- local next_el = curr:get_next_node()
- if next_el and next_el:is_element() and is_span(next_el) then
- return next_el
- -- if the next node is space followed by a matching element, we should add this space
- elseif next_el and next_el:is_text() and get_next(next_el, class) then
- local text = next_el._text
- -- match only text containing just whitespace
- if text:match("^%s+$") then return next_el end
- end
+ local function get_next(curr, class)
+ local next_el = curr:get_next_node()
+ if next_el and next_el:is_element() and is_span(next_el) then
+ return next_el
+ -- if the next node is space followed by a matching element, we should add this space
+ elseif next_el and next_el:is_text() and get_next(next_el, class) then
+ local text = next_el._text
+ -- match only text containing just whitespace
+ if text:match("^%s+$") then return next_el end
end
+ end
+
+ obj:traverse_elements(function(el)
-- loop over all elements and test if the current element is in a list of
-- processed elements (charclasses)
if is_span(el) then
local next_el = get_next(el)
-- loop over the following elements and test whether they are of the same type
-- as the current one
- while next_el do
+ while next_el do
-- save the next element because we will remove it later
local real_next = get_next(next_el)
if get_name(el) == get_name(next_el) and has_matching_attributes(el,next_el) and not el:get_attribute("id") then
- -- it the following element match, copy it's children to the current element
- for _, child in ipairs(next_el:get_children()) do
- el:add_child_node(child)
- end
- -- remove the next element
- next_el:remove_node()
+ join_elements(el, next_el)
-- add the whitespace
elseif next_el:is_text() then
local s = next_el._text
@@ -80,6 +105,36 @@ local function join_characters(obj,par)
end
end)
+ -- process <mi> elements
+ obj:traverse_elements(function(el)
+ local function get_next_mi(curr)
+ local next_el = curr:get_next_node()
+ if next_el and next_el:is_element() then
+ return next_el
+ end
+ end
+ local function has_no_attributes(x)
+ return table_count(x._attr) == 0
+ end
+
+ -- join only subsequential <mi> elements with no attributes
+ if get_name(el) == "mi" and has_no_attributes(el) then
+ local next_el = get_next_mi(el)
+ while next_el do
+ local real_next = get_next_mi(next_el)
+ if get_name(next_el) == "mi" and has_no_attributes(next_el) then
+ join_elements(el, next_el)
+ -- set math variant to italic
+ -- (if the parent <mstyle> element doesn't set it to something else)
+ update_mathvariant(el)
+ else
+ -- break the loop otherwise
+ real_next = nil
+ end
+ next_el = real_next
+ end
+ end
+ end)
-- join text nodes in an element into one
obj:traverse_elements(function(el)
-- save the text