word wrap

luigi/multiline.lua

@@ -0,0 +1,54 @@
+local Multiline = {}
+
+function Multiline.wrap (font, text, limit)
+    local lines = {{ width = 0 }}
+    local advance = 0
+
+    local function append (word, space)
+        local wordAdvance = font:getAdvance(word)
+        local spaceAdvance = font:getAdvance(space)
+        local words = lines[#lines]
+        if advance + wordAdvance > limit then
+            advance = wordAdvance + spaceAdvance
+            lines[#lines + 1] = { width = advance, word, space }
+        else
+            advance = advance + wordAdvance + spaceAdvance
+            words.width = advance
+            words[#words + 1] = word
+            words[#words + 1] = space
+        end
+    end
+
+    local function appendFrag (frag, isFirst)
+        if isFirst then
+            append(frag, '')
+        else
+            local wordAdvance = font:getAdvance(frag)
+            lines[#lines + 1] = { width = wordAdvance, frag }
+            advance = wordAdvance
+        end
+    end
+
+    local leadSpace = text:match '^ +'
+
+    if leadSpace then
+        append('', leadSpace)
+    end
+
+    for word, space in text:gmatch '([^ ]+)( *)' do
+        if word:match '\n' then
+            local isFirst = true
+            for frag in (word .. '\n'):gmatch '([^\n]*)\n' do
+                appendFrag(frag, isFirst)
+                isFirst = false
+            end
+            append('', space)
+        else
+            append(word, space)
+        end
+    end
+
+    return lines
+end
+
+return Multiline