koreader/frontend/document/picdocument.lua

local Document = require("document/document")
local DrawContext = require("ffi/drawcontext")

local PicDocument = Document:new{
    _document = false,
    dc_null = DrawContext.new()
}

function PicDocument:init()
    require "libs/libkoreader-pic"
    ok, self._document = pcall(pic.openDocument, self.file)
    if not ok then
        self.error_message = "failed to open jpeg image"
        return
    end

    self.info.has_pages = true
    self.info.configurable = false

    self:readMetadata()
end

function PicDocument:readMetadata()
    self.info.number_of_pages = 1
end

function PicDocument:register(registry)
    registry:addProvider("jpeg", "application/jpeg", self)
    registry:addProvider("jpg", "application/jpeg", self)
end

return PicDocument