#------------------------------------------------------------------------------
# Copyright (c) 2007, Riverbank Computing Limited
# All rights reserved.
#
# This software is provided without warranty under the terms of the BSD license.
# However, when used with the GPL version of PyQt the additional terms described in the PyQt GPL exception also apply

#
# Author: Riverbank Computing Limited
# Description: <Enthought pyface package component>
#------------------------------------------------------------------------------


# Major package imports.
from pyface.qt import QtGui

# Enthought library imports.
from traits.api import HasTraits, implements

# Local imports.
from pyface.i_image_cache import IImageCache, MImageCache


class ImageCache(MImageCache, HasTraits):
    """ The toolkit specific implementation of an ImageCache.  See the
    IImageCache interface for the API documentation.
    """

    implements(IImageCache)

    ###########################################################################
    # 'object' interface.
    ###########################################################################

    def __init__(self, width, height):
        self._width = width
        self._height = height

    ###########################################################################
    # 'ImageCache' interface.
    ###########################################################################

    def get_image(self, filename):
        image = QtGui.QPixmap(self._width, self._height)

        if QtGui.QPixmapCache.find(filename, image):
            scaled = self._qt4_scale(image)

            if scaled is not image:
                # The Qt cache is application wide so we only keep the last
                # size asked for.
                QtGui.QPixmapCache.remove(filename);
                QtGui.QPixmapCache.insert(filename, scaled)
        else:
            # Load the image from the file and add it to the cache.
            image.load(filename)
            scaled = self._qt4_scale(image)
            QtGui.QPixmapCache.insert(filename, scaled)

        return scaled

    # Qt doesn't distinguish between bitmaps and images.
    get_bitmap = get_image

    ###########################################################################
    # Private 'ImageCache' interface.
    ###########################################################################

    def _qt4_scale(self, image):
        """ Scales the given image if necessary. """

        # Although Qt won't scale the image if it doesn't need to, it will make
        # a deep copy which we don't need.
        if image.width() != self._width or image.height()!= self._height:
            image = image.scaled(self._width, self._height)

        return image

#### EOF ######################################################################
