Method: UIImage#color_at

Defined in:
lib/sugarcube-image/uiimage.rb

#color_at(point) ⇒ Object

Oddly enough, this method doesn't seem to have retina support



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# File 'lib/sugarcube-image/uiimage.rb', line 448

def color_at(point)
  point = SugarCube::CoreGraphics::Point(point)
  point.x *= self.scale
  point.y *= self.scale

  # First get the image into your data buffer
  cgimage = self.CGImage
  width = CGImageGetWidth(cgimage)
  height = CGImageGetHeight(cgimage)
  bytes_per_pixel = 4
  bits_per_component = 8
  bytes_per_row = bytes_per_pixel * width
  @raw_data || begin
    color_space = CGColorSpaceCreateDeviceRGB()
    @raw_data = Pointer.new(:uchar, height * width * 4)
    context = CGBitmapContextCreate(@raw_data, width, height, bits_per_component, bytes_per_row, color_space, KCGImageAlphaPremultipliedLast | KCGBitmapByteOrder32Big)

    CGContextDrawImage(context, CGRectMake(0, 0, width, height), cgimage)
  end

  # Now @raw_data contains the image data in the RGBA8888 pixel format.
  xx = point.x.round
  yy = point.y.round
  byte_index = (bytes_per_row * yy) + xx * bytes_per_pixel
  red = @raw_data[byte_index]
  green = @raw_data[byte_index + 1]
  blue = @raw_data[byte_index + 2]
  alpha = @raw_data[byte_index + 3]
  return [red, green, blue].uicolor(alpha / 255.0)
end