Module: ZplRender::Output::Png

Defined in:
lib/zpl_render/output/png.rb

Class Method Summary collapse

Class Method Details

.encode(canvas, scale: 1) ⇒ Object

Encode a Canvas as a PNG binary string. scale is an integer nearest-neighbor upscale (keeps barcode modules pixel-exact).



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# File 'lib/zpl_render/output/png.rb', line 12

def encode(canvas, scale: 1)
  scale = [scale.to_i, 1].max
  image = ChunkyPNG::Image.new(canvas.width * scale, canvas.height * scale, ChunkyPNG::Color::WHITE)
  black = ChunkyPNG::Color::BLACK
  (0...canvas.height).each do |y|
    (0...canvas.width).each do |x|
      next unless canvas.get(x, y)

      if scale == 1
        image[x, y] = black
      else
        (0...scale).each do |dy|
          (0...scale).each do |dx|
            image[x * scale + dx, y * scale + dy] = black
          end
        end
      end
    end
  end
  image.to_blob(:fast_rgb)
end