pup_help

-- Display help pages, optionally search for key words
function pup.help(query)
local allPages = {
[[===================================================
                     SETUP
===================================================
> Load an existing image
| nfp = pup.loadImage(path)
| nfp = pup.parseImage(string)
   -- NFP image from file or string; as in original

> Create a new image
| nfp = pup.drawFilledBox(x,y,x2,y2,colour[,draw])
| nfp = pup.drawBox(x,y,x2,y2,colour[,draw])
   -- returns image; if draw = false don't print

> Inspect image size
| width, height = nfp:getSize()

* API must be loaded; e.g. 'pup = require("pup")']],
[[===================================================
             MANIPULATE: IMAGE EDITING
===================================================
> Resize the image canvas
| nfp:resizeCanvas(width,height[,bgColour])
   -- crops or pads canvas to specified size

> Overlay an image on top of this one
| nfp:overlay(topImage,xPos,yPos[,resize])
   -- default xPos/yPos = 1, resize = true

> Replace all instances of one colour with another
| nfp:setColour(oldColour,newColour[,mutate])
> Replace the colour of a specific pixel
| nfp:setPixel(x,y,colour[,mutate])

* If mutate = true then original is edited]],
[[===================================================
             MANIPULATE: TRANSFORMATION
===================================================
> Flip an image on given axes
| nfp:mirror("x"|"y"|"xy")

> Rotate an image 90 degrees clockwise
| nfp:rotate()

> Make an image larger (multiplies each pixel)
| nfp:enlarge([factor])
   -- default factor = 2]],
[[===================================================
             MANIPULATE: FORMAT EDITING
===================================================
> Convert NFP image into blit image (BIMG) format
| nfp:blitImage()
   -- 1:1 pixel conversion

> Upscale image to compressed 2x3 pixel clusters
| nfp:upscale([bgColour])
   -- default bgColour = current background

* Upscaling may add pixels to ensure w%2 and h%3]],
[[===================================================
                     OUTPUT
===================================================
> Draw NFP to screen
| nfp:drawImage(x,y)
| pup.drawImage(image,x,y)

> Draw BIMG to screen
| bimg:drawImage(x,y)

> Save to file
| nfp:saveImage(path)
| bimg:saveImage(path)
   -- BIMG is serialised

* File paths must not already exist]],
}

    -- Filter pages if query is provided
    local pages = {}
    if query then
        query = string.lower(query)
        for _, page in ipairs(allPages) do
            if string.find(string.lower(page), query, 1, true) then
                table.insert(pages, page)
            end
        end

        if #pages == 0 then
            term.clear()
            term.setCursorPos(1,1)
            print("No help pages found for: "..query)
            print()
            print("Press any key to exit...")
            os.pullEvent("key")
            return
        end
    else
        pages = allPages
    end

    local oldBg = term.getBackgroundColour()
    local oldFg = term.getTextColour()
    local w,h = term.getSize()
    local currentPage = 1
    local totalPages = #pages

    local function restore()
        term.setBackgroundColour(oldBg)
        term.setTextColour(oldFg)
        term.clear()
        term.setCursorPos(1,1)
    end

	local function drawPage(pageNum)
    	term.clear()
    	term.setCursorPos(1,1)

    	for line in pages[pageNum]:gmatch("[^\n]+") do
        	local trimmed = line:match("^%s*(.-)%s*$") -- trim spaces
        	if trimmed:sub(1,2) == "--" then
            	term.setTextColour(colours.green)   -- comment
        	elseif trimmed:sub(1,1) == "*" then
            	term.setTextColour(colours.red)     -- warning
			elseif trimmed:sub(1,1) == "|" then
				term.setTextColour(colours.yellow)	-- command
			elseif trimmed:sub(1,1) == ">" then
				term.setTextColour(colours.white)   -- subtitle
        	else
            	term.setTextColour(colours.blue)  -- default body
        	end
        	print(line:sub(1, w))
    	end

    	-- Footer instructions
    	term.setTextColour(colours.lightGrey)
    	term.setCursorPos(1, h - 1)
		local footer = "[ < ] Page " .. pageNum .. "/" .. totalPages .. " [ > ]"
    	term.write(footer:sub(1, w))
		term.setCursorPos(1, h)
		term.write("Press [ backspace ] to exit")
	end

    drawPage(currentPage)

    while true do
        local event, key = os.pullEvent("key")
        if key == keys.right then
            if currentPage < totalPages then
                currentPage = currentPage + 1
                drawPage(currentPage)
            end
        elseif key == keys.left then
            if currentPage > 1 then
                currentPage = currentPage - 1
                drawPage(currentPage)
            end
        elseif key == keys.backspace then
            break
        end
    end

    restore()
end