CreOptions: Display weight classes names, in addition to their raw value.

frontend/ui/data/creoptions.lua

@@ -15,6 +15,36 @@ local tableOfNumbersToTableOfStrings = function(numbers)
     return t
 end
 
+-- OS/2 weight classes map
+-- c.f., https://docs.microsoft.com/en-us/typography/opentype/spec/os2#usweightclass
+local usWeightClass = {
+    [100] = C_("Font weight class", "Thin"),
+    [200] = C_("Font weight class", "Extra-light"),
+    [300] = C_("Font weight class", "Light"),
+    [400] = C_("Font weight class", "Regular"),
+    [500] = C_("Font weight class", "Medium"),
+    [600] = C_("Font weight class", "Semi-bold"),
+    [700] = C_("Font weight class", "Bold"),
+    [800] = C_("Font weight class", "Extra-bold"),
+    [900] = C_("Font weight class", "Black"),
+}
+
+local function weightClassToString(weight)
+    if usWeightClass[weight] then
+        return T(_("%1 (%2)"), usWeightClass[weight], weight)
+    else
+        return tostring(weight)
+    end
+end
+
+local function prettifyCreWeights(t)
+    local p = {}
+    for __, v in ipairs(t) do
+        table.insert(p, weightClassToString(v))
+    end
+    return p
+end
+
 local CreOptions = {
     prefix = 'copt',
     {
@@ -537,19 +567,19 @@ Note that your selected font size is not affected by this setting.]]),
                 },
                 help_text = _([[Set the font weight delta from "regular" to apply to all fonts.
 
-- 0 will use the "regular (400)" variation of a font.
-- +1 will use the "medium (500)" variation of a font if available.
-- +3 will use the "bold (700)" variation of a font if available.
+- 0 will use the "Regular (400)" variation of a font.
+- +1 will use the "Medium (500)" variation of a font if available.
+- +3 will use the "Bold (700)" variation of a font if available.
 If a font variation is not available, as well as for fractional adjustments, it will be synthesized from the nearest available weight.]]),
                 help_text_func = function(configurable, document)
                     local font_face = document:getFontFace()
-                    local available_weights = cre.getFontFaceAvailableWeights(font_face)
-                    return T(_("The default font '%1' provides the following weight classes: %2."), font_face, table.concat(available_weights, ", "))
+                    local available_weights = prettifyCreWeights(cre.getFontFaceAvailableWeights(font_face))
+                    return T(_("The default font '%1' provides the following weight classes: %2."), font_face, table.concat(available_weights, C_("List separator", ", ")))
                 end,
                 name_text_hold_callback = optionsutil.showValues,
                 name_text_true_values = true,
                 show_true_value_func = function(val)
-                    return string.format("%d", 400+val*100)
+                    return weightClassToString(400+val*100)
                 end,
             },
             {