Skin ClassicAPI's Interface Options frame and its option controls

SkinCollapseButton's icon no longer takes the mouse, so clicks reach the button under it.

skins/blizzard/options-interface.lua

@@ -0,0 +1,49 @@
+pfUI:RegisterSkin("Options - Interface", function ()
+  local rawborder, border = GetBorderSize()
+  local bpad = rawborder > 1 and border - GetPerfectPixel() or GetPerfectPixel()
+  local cr, cg, cb = PFUI_CLASS_COLORS[UnitClassBase("player")]:GetRGB()
+
+  StripTextures(InterfaceOptionsFrame)
+  CreateBackdrop(InterfaceOptionsFrame, nil, nil, .75)
+  CreateBackdropShadow(InterfaceOptionsFrame)
+
+  local title = GetNoNameObject(InterfaceOptionsFrame, "FontString", "ARTWORK", ADDON_OPTIONS)
+  title:ClearAllPoints()
+  title:SetPoint("TOP", InterfaceOptionsFrame, "TOP", 0, -10)
+
+  CreateBackdrop(InterfaceOptionsFrameAddOns, nil, true, .75)
+  CreateBackdrop(InterfaceOptionsFramePanelContainer, nil, true, .75)
+  SkinScrollbar(InterfaceOptionsFrameAddOnsListScrollBar)
+
+  for _, button in ipairs(InterfaceOptionsFrameAddOns.buttons) do
+    button:GetHighlightTexture():SetTexture(cr, cg, cb, .25)
+
+    -- the list update swaps plus/minus textures on the toggle by path
+    local toggle = _G[button:GetName() .. "Toggle"]
+    SkinCollapseButton(toggle)
+    toggle:SetPushedTexture("")
+    toggle:SetHighlightTexture("")
+    toggle.SetPushedTexture = function() end
+  end
+
+  -- ClassicAPI's own pages (Options\Panel.lua) number their controls
+  local i = 1
+  while _G["ClassicAPIOptionsControl" .. i] do
+    local control = _G["ClassicAPIOptionsControl" .. i]
+    local ctype = control:GetFrameType()
+    if ctype == "CheckButton" then
+      SkinCheckbox(control)
+    elseif ctype == "Slider" then
+      SkinSlider(control)
+    else
+      SkinDropDown(control, nil, nil, nil, true)
+    end
+    i = i + 1
+  end
+
+  SkinButton(InterfaceOptionsFrameDefaults)
+  SkinButton(InterfaceOptionsFrameCancel)
+  SkinButton(InterfaceOptionsFrameOkay)
+  InterfaceOptionsFrameOkay:ClearAllPoints()
+  InterfaceOptionsFrameOkay:SetPoint("RIGHT", InterfaceOptionsFrameCancel, "LEFT", -2*bpad, 0)
+end)