[Android] Don't ship Noto (#5310)

Follow-up to <https://github.com/koreader/koreader/pull/5252>. This greatly reduces the Android package size.

See discussion in <https://github.com/koreader/koreader/pull/5264#issuecomment-525517001>.

Makefile

@@ -351,6 +351,7 @@ androidupdate: all
 	cd $(INSTALL_DIR)/koreader && zip -r9 \
 		../../$(ANDROID_LAUNCHER_DIR)/assets/module/koreader-$(VERSION).zip * \
 		--exclude=*fonts/droid* \
+		--exclude=*fonts/noto* \
 		--exclude=*resources/fonts* \
 		--exclude=*resources/icons/src* \
 		--exclude=*share/man* \

frontend/fontlist.lua

@@ -74,13 +74,14 @@ local function getExternalFontDir()
 end
 
 local function _readList(target, dir)
-    -- lfs.dir non-exsitent directory will give error, weird!
+    -- lfs.dir non-existent directory will give an error, weird!
     local ok, iter, dir_obj = pcall(lfs.dir, dir)
     if not ok then return end
     for f in iter, dir_obj do
-        if lfs.attributes(dir.."/"..f, "mode") == "directory" and f ~= "." and f ~= ".." then
+        local mode = lfs.attributes(dir.."/"..f, "mode")
+        if mode == "directory" and f ~= "." and f ~= ".." then
             _readList(target, dir.."/"..f)
-        else
+        elseif mode == "file" or mode == "link" then
             if string.sub(f, 1, 1) ~= "." then
                 local file_type = string.lower(string.match(f, ".+%.([^.]+)") or "")
                 if file_type == "ttf" or file_type == "ttc"

frontend/ui/font.lua

@@ -2,6 +2,8 @@
 Font module.
 ]]
 
+local is_android = pcall(require, "android")
+
 local FontList = require("fontlist")
 local Freetype = require("ffi/freetype")
 local Screen = require("device").screen
@@ -10,22 +12,22 @@ local logger = require("logger")
 local Font = {
     fontmap = {
         -- default font for menu contents
-        cfont = "noto/NotoSans-Regular.ttf",
+        cfont = "NotoSans-Regular.ttf",
         -- default font for title
         --tfont = "NimbusSanL-BoldItal.cff",
-        tfont = "noto/NotoSans-Bold.ttf",
-        smalltfont = "noto/NotoSans-Bold.ttf",
-        x_smalltfont = "noto/NotoSans-Bold.ttf",
+        tfont = "NotoSans-Bold.ttf",
+        smalltfont = "NotoSans-Bold.ttf",
+        x_smalltfont = "NotoSans-Bold.ttf",
         -- default font for footer
-        ffont = "noto/NotoSans-Regular.ttf",
-        smallffont = "noto/NotoSans-Regular.ttf",
-        largeffont = "noto/NotoSans-Regular.ttf",
+        ffont = "NotoSans-Regular.ttf",
+        smallffont = "NotoSans-Regular.ttf",
+        largeffont = "NotoSans-Regular.ttf",
 
         -- default font for reading position info
-        rifont = "noto/NotoSans-Regular.ttf",
+        rifont = "NotoSans-Regular.ttf",
 
         -- default font for pagination display
-        pgfont = "noto/NotoSans-Regular.ttf",
+        pgfont = "NotoSans-Regular.ttf",
 
         -- selectmenu: font for item shortcut
         scfont = "DroidSansMono.ttf",
@@ -33,7 +35,7 @@ local Font = {
         -- help page: font for displaying keys
         hpkfont = "DroidSansMono.ttf",
         -- font for displaying help messages
-        hfont = "noto/NotoSans-Regular.ttf",
+        hfont = "NotoSans-Regular.ttf",
 
         -- font for displaying input content
         -- we have to use mono here for better distance controlling
@@ -42,16 +44,16 @@ local Font = {
         smallinfont = "DroidSansMono.ttf",
 
         -- font for info messages
-        infofont = "noto/NotoSans-Regular.ttf",
+        infofont = "NotoSans-Regular.ttf",
 
         -- small font for info messages
-        smallinfofont = "noto/NotoSans-Regular.ttf",
+        smallinfofont = "NotoSans-Regular.ttf",
         -- small bold font for info messages
-        smallinfofontbold = "noto/NotoSans-Bold.ttf",
+        smallinfofontbold = "NotoSans-Bold.ttf",
         -- extra small font for info messages
-        x_smallinfofont = "noto/NotoSans-Regular.ttf",
+        x_smallinfofont = "NotoSans-Regular.ttf",
         -- extra extra small font for info messages
-        xx_smallinfofont = "noto/NotoSans-Regular.ttf",
+        xx_smallinfofont = "NotoSans-Regular.ttf",
     },
     sizemap = {
         cfont = 24,
@@ -75,8 +77,8 @@ local Font = {
         xx_smallinfofont = 18,
     },
     fallbacks = {
-        [1] = "noto/NotoSans-Regular.ttf",
-        [2] = "noto/NotoSansCJKsc-Regular.otf",
+        [1] = "NotoSans-Regular.ttf",
+        [2] = "NotoSansCJKsc-Regular.otf",
         [3] = "freefont/FreeSans.ttf",
         [4] = "freefont/FreeSerif.ttf",
     },
@@ -85,6 +87,10 @@ local Font = {
     faces = {},
 }
 
+if is_android then
+    table.insert(Font.fallbacks, 3, "DroidSansFallback.ttf") -- for some ancient pre-4.4 Androids
+end
+
 --- Gets font face object.
 -- @string font
 -- @int size optional size
@@ -108,13 +114,38 @@ function Font:getFace(font, size)
         end
         local builtin_font_location = FontList.fontdir.."/"..realname
         local ok, face = pcall(Freetype.newFace, builtin_font_location, size)
+
+        -- We don't ship Droid and Noto on Android because they're system fonts.
+        -- This cuts package size in half, but 4.4 and older systems
+        -- might not ship Noto.
+        if not ok and is_android and realname:match("^Noto") then
+            local system_font_location = "/system/fonts"
+            logger.dbg("Font:", realname, "not found. Trying system location.")
+
+            ok, face = pcall(Freetype.newFace, system_font_location.."/"..realname, size)
+
+            -- Relevant Noto font not found on this device, fall back to Droid
+            if not ok then
+                if realname:match("Bold") then
+                    realname = "DroidSans-Bold.ttf"
+                else
+                    realname = "DroidSans.ttf"
+                end
+            end
+        end
+
         -- Not all fonts are bundled on all platforms because they come with the system.
         -- In that case, search through all font folders for the requested font.
-        if not ok and font ~= realname then
+        if not ok then
             local fonts = FontList:getFontList()
+            local escaped_realname = realname:gsub("[-]", "%%-")
+
             for _k, _v in ipairs(fonts) do
-                if _v:find(realname) then
+                if _v:find(escaped_realname) then
+                    logger.dbg("Found font:", realname, "in", _v)
                     ok, face = pcall(Freetype.newFace, _v, size)
+
+                    if ok then break end
                 end
             end
         end