From 419cb82a2de5a20c0a89c05016da47bd91ef51ef Mon Sep 17 00:00:00 2001
From: Benedikt Ziemons <ben@rs485.network>
Date: Sun, 2 Jun 2024 20:41:58 +0200
Subject: [PATCH] [listframes] cache estimatedTotalHeight

---
 listframes.lua | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/listframes.lua b/listframes.lua
index a72f4b0..6f1ef62 100644
--- a/listframes.lua
+++ b/listframes.lua
@@ -3,6 +3,7 @@ local subFrames = {}
 local length = 0
 local frame = term.current()
 local drawEntry = nil
+local estimatedTotalHeight = 0
 
 -- pagination start line (not number of entries!)
 local paginationPos = 1
@@ -58,7 +59,11 @@ local function redrawEntry(idx)
         local tw, th = frame.getSize()
         local xPos, yPos = entryFrame.getPosition()
         local xSize, ySize = entryFrame.getSize()
-        entryFrame.setVisible((yPos + ySize) > 1 and yPos <= th)
+        local yEnd = yPos+ySize-1
+        entryFrame.setVisible(yEnd > 0 and yPos <= th)
+        if yEnd > estimatedTotalHeight then
+            estimatedTotalHeight = yEnd
+        end
     end
 end
 
@@ -93,6 +98,7 @@ local function updateItemAt(idx, item)
 end
 
 local function clearFrom(idx)
+    estimatedTotalHeight = (idx-1).."?"
     local tw, th = frame.getSize()
     for j = length, idx, -1 do
         backingList[j] = nil
@@ -144,16 +150,13 @@ local function updatePage(scrollPos)
 end
 
 local function estimatedHeight()
-    local firstEntryFrame = subFrames[1]
     local lastEntryFrame = subFrames[length]
-    if firstEntryFrame ~= nil and lastEntryFrame ~= nil then
-        local firstXPos, firstYPos = firstEntryFrame.getPosition()
+    if lastEntryFrame ~= nil and lastEntryFrame.isVisible() then
         local xPos, yPos = lastEntryFrame.getPosition()
         local xSize, ySize = lastEntryFrame.getSize()
-        return yPos-firstYPos+ySize
-    else
-        return length
+        estimatedTotalHeight = yPos+ySize-1
     end
+    return estimatedTotalHeight
 end