refactor image optimize

Makefile

@@ -9,7 +9,7 @@ thumb := $(bin)/thumb
 rss := $(bin)/rss
 sitemap := $(bin)/sitemap
 
-install: html static image dist/sitemap.xml dist/rss.xml
+install: html static dist/sitemap.xml dist/rss.xml
 
 html: $(html_files)
 
@@ -27,11 +27,7 @@ dist/%.html: src/%.md templates/* $(MD_TO_HTML)
 static:
 	cd $(source) && find . -type f ! -name "*.md" -print0 | cpio -pdvm0 ../$(output)
 
-image:
-	@$(thumb)
-
 clean: 
 	@rm -vrf $(output)
 
-
-.PHONY: install html static image clean
+.PHONY: install html static clean

filters/img_filter.lua

@@ -1,25 +1,80 @@
 local path = require("pandoc.path")
+local utils = require("pandoc.utils")
+
+local function get_file_absolute_path(file)
+	local current_file = string.gsub(PANDOC_STATE.input_files[1], "([^/]*%.%w+)$", "")
+	return "/" .. path.join({ current_file, file })
+end
+
+local remove_file_name = function(file)
+	return string.gsub(file, "([^/]*%.%w+)$", "")
+end
+
+local remove_src_prefix = function(file)
+	return string.gsub(file, "src/", "")
+end
+
+local function get_file_extension(file)
+	local _, ext = path.split_extension(file)
+	return ext
+end
+
+local get_file_name = function(file)
+	local name, _ = path.split_extension(file)
+	return name
+end
+
+local is_gif = function(file)
+	local ext = get_file_extension(file)
+	return ext == ".gif"
+end
+
+local src = "src"
+local dist = "dist"
+
+local function get_thumb_path(file)
+	-- add thumbs/ to the path
+	local thumb = string.gsub(file, "([^/]*%.%w+)$", "thumbs/%1")
+
+	-- change extension to .webp
+	return get_file_name(thumb) .. ".webp"
+end
 
 function Image(img)
-	local src = img.src
 	img.attributes.loading = "lazy"
 
-	local _, ext = path.split_extension(src)
-	if ext == ".gif" then
+	if is_gif(img.src) then
 		return img
 	end
 
-	-- Add the 'thumbs/' prefix to the image filename
-	img.src = string.gsub(img.src, "([^/]*%.%w+)$", "thumbs/%1")
+	local absolute_path = remove_src_prefix(get_file_absolute_path(img.src))
+	local thumb = get_thumb_path(absolute_path)
+
+	local input_file = src .. absolute_path
+	local output_file = dist .. thumb
+	local output_path = dist .. remove_file_name(thumb)
 
-	-- Split the image filename and file extension
-	local filename = path.split_extension(img.src)
+	os.execute("mkdir -p " .. output_path)
+	os.execute("cwebp -resize 640 0 -q 80 " .. input_file .. " -o " .. output_file)
 
-	-- Set the file extension to '.webp'
-	img.src = filename .. ".webp"
+	img.src = thumb
+
+	-- get width and height for thumb image using identify command
+	local handle = io.popen('identify -format "%w %h" ' .. output_file)
+	local result = handle:read("*a")
+	handle:close()
+	local width, height = result:match("(%d+) (%d+)")
+
+	if width then
+		img.attributes.width = width
+	end
+
+	if height then
+		img.attributes.height = height
+	end
 
 	-- Wrap the image in an anchor tag
-	local link = pandoc.Link(img, src)
+	local link = pandoc.Link(img, absolute_path)
 
 	-- Return the modified image
 	return link