benilla-octo/crates/benilla-app/assets/ui/ItemButtonTemplate.xml

<!--
    The reference's `ItemButtonTemplate.lua` helper family (transcribed whole, like
    TextStatusBar.xml) — the eight `SetItemButton*` globals every 1.12 window uses to paint an item
    slot: its icon, its stack count, its merchant stock line, and the four vertex-colour verbs.

    **Why this file exists, and what it cost to be without it.** The director installed Bagnon, hit
    B, and got a frame with a title and a gold line and NO BAG SLOTS. `Bagnon_Core/core/Item.lua`
    ends every slot update with

        l.204   SetItemButtonDesaturated(item, locked, 0.5, 0.5, 0.5)
        l.209   SetItemButtonTexture(item, texture)
        l.210   SetItemButtonCount(item, itemCount)

    and all three were nil. The raise lands inside `BagnonFrame_AddBag`'s per-slot loop, so the
    FIRST slot aborts the loop, `frame.size` never advances, `BagnonFrame_Layout` never runs and
    the window is left exactly as wide as its own border. `ui_script::bagnon_render_tests` is the
    reproduction.

    These are FrameXML, not engine (decision 1190's split): the real client ships them as Lua in
    `Interface\FrameXML\ItemButtonTemplate.lua`, so they belong here beside our other
    transcriptions rather than in a Rust binding. Read off the install's own copy with the
    `mpqcat` example over `WoW/Data/interface.MPQ` — not from memory.
    (An XML comment may not contain a double hyphen, which is why no command line is spelled out
    here; `benilla-mpq/examples/mpqcat.rs`'s own header carries the invocation.)

    **Corpus demand, counted rather than assumed** (the 218-addon vanilla corpus; `grep -rl`, one
    row per verb, addons/sites):

        SetItemButtonTexture                    4 addons / 19 sites
        SetItemButtonDesaturated                3 addons /  8 sites
        SetItemButtonCount                      3 addons /  7 sites
        SetItemButtonTextureVertexColor         3 addons /  7 sites
        SetItemButtonNormalTextureVertexColor   1 addon  /  2 sites
        SetItemButtonNameFrameVertexColor       1 addon  /  2 sites
        SetItemButtonSlotVertexColor            0        /  0
        SetItemButtonStock                      0        /  0

    Six addons in all — Bagnon_Core, CT_MailMod, CT_MasterMod, AdvancedTradeSkillWindow,
    QuestHistory, SpecialTalentUI. The last two rows have **zero** corpus callers and are here
    anyway because this is one reference file transcribed whole and they are two lines each; that
    is stated rather than dressed up as demand (1210).

    **The virtual `ItemButtonTemplate` Button is deliberately NOT here.** The harness's template
    demand ranks it at zero on both axes — no corpus addon names it in a `CreateFrame` fourth
    argument or an XML `inherits=` (they name their own `*ItemButtonTemplate`s, or
    `ContainerFrameItemButtonTemplate`) — and our own bag windows already have
    `BenillaBagSlotTemplate`. Building an unwanted template is exactly the unmeasured work 1210
    was written about.
-->
<Ui xmlns="http://www.blizzard.com/wow/ui/">
    <Script><![CDATA[
        -- The naming contract every verb below rests on: an "item button" is a Button whose own
        -- name prefixes its regions — `<name>IconTexture`, `<name>Count`, `<name>Stock`,
        -- `<name>NormalTexture`, `<name>NameFrame`, `<name>SlotTexture`. That is the reference's
        -- `$parent…` template shape, and it is why these are free functions taking a button rather
        -- than widget methods: any button that follows the naming works, whoever built it.
        --
        -- Nil guards are the REFERENCE's, not ours — one on `button` per verb, and one on the icon
        -- region in SetItemButtonDesaturated. A missing region anywhere else raises, and that is
        -- the right loudness: "this is not an item button" is a real mistake, and 1203's lesson is
        -- that the silent version of a failure is the expensive one.

        function SetItemButtonCount(button, count)
            if not button then
                return
            end
            if not count then
                count = 0
            end
            button.count = count
            -- `isBag` is the reference's own flag for a bag button, where even a single item
            -- counts as a number worth showing.
            if count > 1 or (button.isBag and count > 0) then
                if count > 999 then
                    count = "*"
                end
                getglobal(button:GetName() .. "Count"):SetText(count)
                getglobal(button:GetName() .. "Count"):Show()
            else
                getglobal(button:GetName() .. "Count"):Hide()
            end
        end

        function SetItemButtonStock(button, numInStock)
            if not button then
                return
            end
            -- The reference defaults this to `""` and then compares it with `> 0`, which is a
            -- string/number comparison Lua refuses — a raise on the only path the default can
            -- reach. Ours defaults to 0, which is what the branch below actually means. Not aping
            -- a quirk (method step 3); the behaviour on every reachable path is identical.
            if not numInStock then
                numInStock = 0
            end
            button.numInStock = numInStock
            if numInStock > 0 then
                getglobal(button:GetName() .. "Stock"):SetText(format(MERCHANT_STOCK, numInStock))
                getglobal(button:GetName() .. "Stock"):Show()
            else
                getglobal(button:GetName() .. "Stock"):Hide()
            end
        end

        function SetItemButtonTexture(button, texture)
            if not button then
                return
            end
            -- Show/Hide FIRST, then SetTexture — the reference's order, and it matters: a nil
            -- texture hides the region rather than leaving an empty quad behind.
            if texture then
                getglobal(button:GetName() .. "IconTexture"):Show()
            else
                getglobal(button:GetName() .. "IconTexture"):Hide()
            end
            getglobal(button:GetName() .. "IconTexture"):SetTexture(texture)
        end

        function SetItemButtonTextureVertexColor(button, r, g, b)
            if not button then
                return
            end
            getglobal(button:GetName() .. "IconTexture"):SetVertexColor(r, g, b)
        end

        function SetItemButtonDesaturated(button, desaturated, r, g, b)
            if not button then
                return
            end
            local icon = getglobal(button:GetName() .. "IconTexture")
            if not icon then
                return
            end
            -- The reference asks the texture itself whether the desaturating shader is available
            -- (`local shaderSupported = icon:SetDesaturated(desaturated)`) and falls through to a
            -- flat grey tint when it is not — 1.12 ran on fixed-function hardware where that was
            -- the ordinary answer. benilla has no `Texture:SetDesaturated` at all (it is the top
            -- row of the harness's missing-METHODS ranking, 61 corpus addons), so the feature test
            -- is on the METHOD's existence and the no-shader branch is the one we take. When the
            -- real verb lands this line starts using it with nothing else to change.
            local shaderSupported = icon.SetDesaturated and icon:SetDesaturated(desaturated)
            if not desaturated then
                r = 1.0
                g = 1.0
                b = 1.0
            elseif not r or not shaderSupported then
                r = 0.5
                g = 0.5
                b = 0.5
            end
            icon:SetVertexColor(r, g, b)
        end

        function SetItemButtonNormalTextureVertexColor(button, r, g, b)
            if not button then
                return
            end
            getglobal(button:GetName() .. "NormalTexture"):SetVertexColor(r, g, b)
        end

        function SetItemButtonNameFrameVertexColor(button, r, g, b)
            if not button then
                return
            end
            getglobal(button:GetName() .. "NameFrame"):SetVertexColor(r, g, b)
        end

        function SetItemButtonSlotVertexColor(button, r, g, b)
            if not button then
                return
            end
            getglobal(button:GetName() .. "SlotTexture"):SetVertexColor(r, g, b)
        end
    ]]></Script>
</Ui>