Add back button

compcount.lua

@@ -1,6 +1,7 @@
 local mon = peripheral.find("monitor")
 assert(mon, "Kein Monitor gefunden")
 local monName = peripheral.getName(mon)
+local SCREEN_WIDTH = 40
 
 mon.setTextScale(0.5)
 
@@ -17,6 +18,8 @@ local baseItemIds
 local itemById
 local defaultBaseId
 local fallbackIcon = false
+local backButton = false
+local drawOverview
 
 local function ensureChainsLoaded()
   if not chainItemsByBaseId then
@@ -124,6 +127,18 @@ local function getFallbackIcon()
   return fallbackIcon
 end
 
+local function getBackButton()
+  if backButton == false then
+    backButton = parseNfpImage(table.concat({
+      "e e",
+      " e ",
+      "e e",
+    }, "\n"))
+  end
+
+  return backButton
+end
+
 local function imageSize(img)
   local w, h = 0, 0
 
@@ -267,8 +282,12 @@ end
 local function drawPage(base_id)
     local pageItems = getPageItems(base_id)
     local defaultIcon = getFallbackIcon()
+    local backIcon = getBackButton()
+    local backWidth, backHeight = imageSize(backIcon)
+    local backX = SCREEN_WIDTH - backWidth + 1
 
     frame.buffer:clear()
+    drawNfpScaled(frame.buffer, backIcon, (backX - 1) * 2 + 1, 1)
 
     -- TODO LATER get item counts from me-system using item ids. For now, just use random numbers.
 
@@ -280,9 +299,18 @@ local function drawPage(base_id)
 
     assertBufferValid(frame)
     frame:drawBuffer()
+
+    while true do
+        local _, side, x, y = os.pullEvent("monitor_touch")
+
+        if side == monName and x >= backX and x < backX + backWidth and y >= 1 and y <= backHeight then
+            drawOverview()
+            return
+        end
+    end
 end
 
-local function drawOverview()
+drawOverview = function()
     local items = getBaseItemIds()
     local visibleItemCount = math.min(math.max(#items, 9), 9)
     -- TODO LATER: get item counts from me-system using item, then sort items according to their counts and display the top 9. For now, just use random numbers.