class FreeImage::Memory

  1. lib/free-image/sources/memory.rb
Superclass: AbstractSource

Summary ↑

Supports loading and saving images to a Ruby string.

Usage ↑

# Read an image from a byte string
bytes = ::File.read('test/fixtures/lena.png', :encoding => Encoding::BINARY)
image = FreeImage::Memory.open(bytes)

# Save an image to a byte string
dest = FreeImage::Memory.new
image.save(dest, :jpeg)
dest.bytes

Methods

Public Class

  1. new

Public Instance

  1. format
  2. memory
  3. save

Attributes

memory [R]

MemoryStream used to read and write data

Public Class methods

new (bytes = nil)

Create a new FreeImage::File instance that can read and write image data from memory.

Parameters ↑

bytes

If specified, FreeImage will read image from the bytes string and treat it as readonly. If not specified, then FreeImage will create a writable memory stream.

[show source] 
# File lib/free-image/sources/memory.rb, line 141
def initialize(bytes = nil)
  @memory = MemoryStream.new(bytes)
end

Public Instance methods

memory.format -> :format

Returns the image format for a memory stream. If the image format cannot be determined the :unknown will be returned.

[show source] 
# File lib/free-image/sources/memory.rb, line 150
def format
  result = FreeImage.FreeImage_GetFileTypeFromMemory(@memory, 0)
  FreeImage.check_last_error
  result
end
memory.save(format = nil, flags = 0) -> boolean

Saves an image to memory.

Parameters ↑

format

The format to save the image to.

flags

Format specific flags that control how a bitmap is saved. These flags are defined as constants on the AbstractSource class. Flags can be combined using Ruby's bitwise or operator (|)

Usage ↑

image = Bimap.open('<path_to_file>')
dst = FreeImage::Memory.new
dst.save(image, :jpeg, AbtractSource::JPEG_QUALITYSUPERB | AbtractSource::JPEG_PROGRESSIVE)
dst.bytes
[show source] 
# File lib/free-image/sources/memory.rb, line 175
def save(bitmap, format, flags = 0)
  result = FreeImage.FreeImage_SaveToMemory(format, bitmap, @memory, flags)
  FreeImage.check_last_error
  result
end