Method: FreeImage::Bitmap.create

Defined in:

lib/free-image/bitmap.rb

.create(width, height, bits_per_pixel, red_mask = 0, green_mask = 0, blue_mask = 0) ⇒ Object

Creates a new image with the specified width, height and bits per pixel.

Parameters

width

The width of the new image

height

The height of the new image

bits_per_pixel

The size in bits of a pixel

red_mask

The bit-layout of the red color component in a bitmap

green_mask:P: The bit-layout of the green color component in a bitmap

blue_mask

The bit-layout of the blue color component in a bitmap

The last three parameter are used to tell FreeImage the bit-layout of the color components in the bitmap, e.g. where in a pixel the red, green and blue components are stored.

To give you an idea about how to interpret the color masks: when red_mask is 0xFF000000 this means that the last 8 bits in one pixel are used for the color red. When green_mask is 0x000000FF, it means that the first 8 bits in a pixel are used for the color green.

The new image is initially filled completely with zeroes. Zero in a image is usually interpreted as black. This means that if your bitmap is palletized it will contain a completely black palette. You can access, and hence populate the palette via #palette.

For 8-bit images, a default greyscale palette will also be created.

# File 'lib/free-image/bitmap.rb', line 74

def self.create(width, height, bits_per_pixel, red_mask = 0, green_mask = 0, blue_mask = 0)
  ptr = FreeImage.FreeImage_Allocate(width, height, bits_per_pixel, red_mask, green_mask, blue_mask)
  FreeImage.check_last_error
  new(ptr)
end