Lua Requires Chilkat v11.7.0+

QR Code Quiet Zone, Padding and Rotation

See more QR Code Examples

Demonstrates the space around a QR code and its rotation. The quiet zone is the blank margin a reader needs around the symbol. It is measured in modules, the QR standard requires 4, and QrCode will make it larger but not smaller. Padding is extra space outside the quiet zone, measured in the render units (pixels by default). Rotation turns the whole image by 90, 180 or 270 degrees. A QR code reads the same at any rotation. Lua

local chilkat = require("chilkat")

-- This example requires the Chilkat API to have been previously unlocked.
-- See Global Unlock Sample for sample code.

local json = chilkat.JsonObject.new()
json:update_string("payload.text", "https://www.chilkatsoft.com/")
json:update_int("render.moduleSize", 6)

-- A quiet zone of 6 modules on every side instead of the standard 4.
json:update_int("render.quietZone.left", 6)
json:update_int("render.quietZone.top", 6)
json:update_int("render.quietZone.right", 6)
json:update_int("render.quietZone.bottom", 6)

-- 10 more pixels of background around that.
json:update_int("render.padding", 10)

-- Turn the image a quarter turn clockwise.
json:update_int("render.rotation", 90)

json:update_string("output.path", "qa_output/qr_margins.png")
json:update_bool("output.overwrite", true)
json:update_string("output.return", "none")

local fmt = chilkat.Formats.new()
local jsonOut = chilkat.JsonObject.new()
local success = fmt:qr_code("generate", json, jsonOut)
if not success then
    print(fmt.last_error_text)
    return
end

print("module: " .. jsonOut:int_of("measurements[0].pitch") .. " pixels")
print("symbol: " .. jsonOut:int_of("measurements[0].symbolWidth") .. " x " .. jsonOut:int_of("measurements[0].symbolHeight") .. " pixels at (" .. jsonOut:int_of("measurements[0].symbolX") .. "," .. jsonOut:int_of("measurements[0].symbolY") .. ")")
print("quiet zone: " .. jsonOut:int_of("measurements[0].quietZonePx.left") .. " pixels")
print("padding: " .. jsonOut:int_of("measurements[0].paddingPx") .. " pixels")
print("rotation: " .. jsonOut:int_of("measurements[0].rotation"))
print("image: " .. jsonOut:int_of("measurements[0].canvasWidth") .. " x " .. jsonOut:int_of("measurements[0].canvasHeight") .. " pixels")

-- The image, enlarged, with the quiet zone and the padding tinted here to show where they are.
-- In the image itself both are plain white.  A QR code has no finder pattern (the large squares)
-- in its bottom right corner.  After the quarter turn that corner is at the bottom left:

-- 

-- Sample output:

-- module: 6 pixels
-- symbol: 174 x 174 pixels at (46,46)
-- quiet zone: 36 pixels
-- padding: 10 pixels
-- rotation: 90
-- image: 266 x 266 pixels