Metadata-Version: 1.1
Name: blend-modes
Version: 2.0.2
Summary: Image processing blend modes
Home-page: https://github.com/flrs/blend_modes
Author: Florian Roscheck
Author-email: florian.ros.check+blendmodes@gmail.com
License: MIT
Description: Blend Modes
        ===========
        
        This Python package implements blend modes for images.
        
        Description
        -----------
        
        The Blend Modes package enables blending different images, or image
        layers, by means of blend modes. These modes are commonly found in
        graphics programs like `Adobe
        Photoshop <http://www.adobe.com/Photoshop>`__ or
        `GIMP <https://www.gimp.org/>`__.
        
        Blending through blend modes allows to mix images in a variety of ways.
        This package currently supports the following blend modes (name of the
        respective functions in the package in ``italics``):
        
        -  Soft Light (``blend_modes.soft_light``)
        -  Lighten Only (``blend_modes.lighten_only``)
        -  Dodge (``blend_modes.dodge``)
        -  Addition (``blend_modes.addition``)
        -  Darken Only (``blend_modes.darken_only``)
        -  Multiply (``blend_modes.multiply``)
        -  Hard Light (``blend_modes.hard_light``)
        -  Difference (``blend_modes.difference``)
        -  Subtract (``blend_modes.subtract``)
        -  Grain Extract (known from GIMP, ``blend_modes.grain_extract``)
        -  Grain Merge (known from GIMP, ``blend_modes.grain_merge``)
        -  Divide (``blend_modes.divide``)
        -  Overlay (``blend_modes.overlay``)
        -  Normal (``blend_modes.normal``)
        
        The intensity of blending can be controlled by means of an *opacity*
        parameter that is passed into the functions. See `Usage <#usage>`__ for
        more information.
        
        The Blend Modes package is optimized for speed. It takes advantage of
        vectorization through Numpy. Further speedup can be achieved when
        implementing the package in Cython. However, Cython implementation is
        not part of this package.
        
        Usage
        -----
        
        The blend mode functions take image data expressed as arrays as an
        input. These image data are usually obtained through functions from
        image processing packages. Two popular image processing packages in
        Python are `PIL <https://pypi.python.org/pypi/PIL>`__ or its fork
        `Pillow <https://pypi.python.org/pypi/Pillow/>`__ and
        `OpenCV <http://opencv.org/>`__. The examples in this chapter show how
        to blend images using these packages.
        
        Input and Output Formats
        ~~~~~~~~~~~~~~~~~~~~~~~~
        
        A typical blend mode operation is called like this:
        
        .. code:: python
        
            blended_img = soft_light(bg_img, fg_img, opacity)
        
        The blend mode functions expect
        `Numpy <https://pypi.python.org/pypi/numpy>`__ float arrays in the
        format [*pixels in dimension 1*,\ *pixels in dimension 2*,4] as an
        input. Both images needs to have the same size, so the *pixels in
        dimension 1* must be the same for ``bg_img`` and ``fg_img``. Same
        applies to the *pixels in dimension 2*. Thus, a valid shape of the
        arrays would be ``bg_img.shape == (640,320,4)`` and
        ``fg_img.shape == (640,320,4)``.
        
        The order of the channels in the third dimension should be *R, G, B, A*,
        where *A* is the alpha channel. All values should be *floats* in the
        range *0.0 <= value <= 255.0*.
        
        The blend mode functions return arrays in the same format as the input
        format.
        
        Examples
        ~~~~~~~~
        
        The following examples show how to use the Blend Modes package in
        typical applications.
        
        The examples are structured in three parts:
        
        1. Load background and foreground image. The foreground image is to be
           blended onto the background image.
        
        2. Use the Blend Modes package to blend the two images via the "soft
           light" blend mode. The package supports multiple blend modes. See the
           `Description <#description>`__ for a full list.
        
        3. Display the blended image.
        
        PIL/Pillow Example
        ^^^^^^^^^^^^^^^^^^
        
        The following example shows how to use the Blend Modes package with the
        `PIL <https://pypi.python.org/pypi/PIL>`__ or
        `Pillow <https://pypi.python.org/pypi/Pillow/>`__ packages.
        
        .. code:: python
        
            from PIL import Image
            import numpy
            from blend_modes import soft_light
        
            # Import background image
            background_img_raw = Image.open('background.png')  # RGBA image
            background_img = numpy.array(background_img_raw)  # Inputs to blend_modes need to be numpy arrays.
            background_img_float = background_img.astype(float)  # Inputs to blend_modes need to be floats.
        
            # Import foreground image
            foreground_img_raw = Image.open('foreground.png')  # RGBA image
            foreground_img = numpy.array(foreground_img_raw)  # Inputs to blend_modes need to be numpy arrays.
            foreground_img_float = foreground_img.astype(float)  # Inputs to blend_modes need to be floats.
        
            # Blend images
            opacity = 0.7  # The opacity of the foreground that is blended onto the background is 70 %.
            blended_img_float = soft_light(background_img_float, foreground_img_float, opacity)
        
            # Convert blended image back into PIL image
            blended_img = numpy.uint8(blended_img_float)  # Image needs to be converted back to uint8 type for PIL handling.
            blended_img_raw = Image.fromarray(blended_img)  # Note that alpha channels are displayed in black by PIL by default.
                                                            # This behavior is difficult to change (although possible).
                                                            # If you have alpha channels in your images, then you should give
                                                            # OpenCV a try.
        
            # Display blended image
            blended_img_raw.show()
        
        OpenCV Example
        ^^^^^^^^^^^^^^
        
        The following example shows how to use the Blend Modes package with
        `OpenCV <http://opencv.org/>`__.
        
        .. code:: python
        
            import cv2  # import OpenCV
            import numpy
            from blend_modes import soft_light
        
            # Import background image
            background_img_float = cv2.imread('background.png',-1).astype(float)
        
            # Import foreground image
            foreground_img_float = cv2.imread('foreground.png',-1).astype(float)
        
            # Blend images
            opacity = 0.7  # The opacity of the foreground that is blended onto the background is 70 %.
            blended_img_float = soft_light(background_img_float, foreground_img_float, opacity)
        
            # Display blended image
            blended_img_uint8 = blended_img_float.astype(numpy.uint8)  # Convert image to OpenCV native display format
            cv2.imshow('window', blended_img_uint8)
            cv2.waitKey()  # Press a key to close window with the image.
        
        Installation
        ------------
        
        The Blend Modes package can be installed through pip:
        ``$ pip install blend_modes``
        
        Dependencies
        ------------
        
        The Blend Modes package needs
        `Numpy <https://pypi.python.org/pypi/numpy>`__ to function correctly.
        For loading images the following packages have been successfully used:
        
        -  `PIL <https://pypi.python.org/pypi/PIL>`__
        -  `Pillow <https://pypi.python.org/pypi/Pillow/>`__
        -  `OpenCV <http://opencv.org/>`__
        
        See Also
        --------
        
        Blend modes are further described on
        `Wikipedia <https://en.wikipedia.org/wiki/Blend_modes>`__. An actual
        implementation can be found in the `GIMP source
        code <https://git.gnome.org/browse/gimp/tree/app/operations/>`__, e.g.
        in the file that describes the *division* operation,
        `gimpoperationdividecode.c <https://git.gnome.org/browse/gimp/tree/app/operations/gimpoperationdividemode.c>`__.
        
        Contribution
        ------------
        
        I am happy about any contribution or feedback. Please let me know about
        your comments via the Issues tab on
        `GitHub <https://github.com/flrs/blend_modes/issues>`__.
        
        License
        -------
        
        The Blend Modes package is distributed under the `MIT License
        (MIT) <https://github.com/flrs/blend_modes/blob/master/LICENSE.txt>`__.
        Please also take note of the licenses of the dependencies.
        
Keywords: image processing blend modes
Platform: UNKNOWN
Classifier: Development Status :: 5 - Production/Stable
Classifier: Intended Audience :: Developers
Classifier: Topic :: Multimedia :: Graphics :: Graphics Conversion
Classifier: License :: OSI Approved :: MIT License
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 3.5
