def get_combined_transformation_list(self, *args, **kwargs):
"""
Return a list of transformation containing the server side
document page transformation as well as tranformations created
from the arguments as transient interactive transformation.
"""
# Convert arguments into transformations
transformations = kwargs.get('transformations', [])
# Set sensible defaults if the argument is not specified or if the
# argument is None
width = kwargs.get('width', setting_display_width.value) or setting_display_width.value
height = kwargs.get('height', setting_display_height.value) or setting_display_height.value
rotation = kwargs.get('rotation', DEFAULT_ROTATION) or DEFAULT_ROTATION
zoom_level = kwargs.get('zoom', DEFAULT_ZOOM_LEVEL) or DEFAULT_ZOOM_LEVEL
if zoom_level < setting_zoom_min_level.value:
zoom_level = setting_zoom_min_level.value
if zoom_level > setting_zoom_max_level.value:
zoom_level = setting_zoom_max_level.value
# Generate transformation hash
transformation_list = []
# Stored transformations first
for stored_transformation in Transformation.objects.get_for_model(self, as_classes=True):
transformation_list.append(stored_transformation)
# Interactive transformations second
for transformation in transformations:
transformation_list.append(transformation)
if rotation:
transformation_list.append(
TransformationRotate(degrees=rotation)
)
if width:
transformation_list.append(
TransformationResize(width=width, height=height)
)
if zoom_level:
transformation_list.append(TransformationZoom(percent=zoom_level))
return transformation_list
def generate_image(self, *args, **kwargs):
# Convert arguments into transformations
transformations = kwargs.get('transformations', [])
# Set sensible defaults if the argument is not specified or if the
# argument is None
size = kwargs.get('size', setting_display_size.value) or setting_display_size.value
rotation = kwargs.get('rotation', DEFAULT_ROTATION) or DEFAULT_ROTATION
zoom_level = kwargs.get('zoom', DEFAULT_ZOOM_LEVEL) or DEFAULT_ZOOM_LEVEL
if zoom_level < setting_zoom_min_level.value:
zoom_level = setting_zoom_min_level.value
if zoom_level > setting_zoom_max_level.value:
zoom_level = setting_zoom_max_level.value
# Generate transformation hash
transformation_list = []
# Stored transformations first
for stored_transformation in Transformation.objects.get_for_model(self, as_classes=True):
transformation_list.append(stored_transformation)
# Interactive transformations second
for transformation in transformations:
transformation_list.append(transformation)
if rotation:
transformation_list.append(
TransformationRotate(degrees=rotation)
)
if size:
transformation_list.append(
TransformationResize(
**dict(zip(('width', 'height'), (size.split('x'))))
)
)
if zoom_level:
transformation_list.append(TransformationZoom(percent=zoom_level))
cache_filename = '{}-{}'.format(
self.cache_filename, BaseTransformation.combine(transformation_list)
)
# Check is transformed image is available
logger.debug('transformations cache filename: %s', cache_filename)
if not setting_disable_transformed_image_cache.value and cache_storage_backend.exists(cache_filename):
logger.debug(
'transformations cache file "%s" found', cache_filename
)
else:
logger.debug(
'transformations cache file "%s" not found', cache_filename
)
image = self.get_image(transformations=transformation_list)
with cache_storage_backend.open(cache_filename, 'wb+') as file_object:
file_object.write(image.getvalue())
self.cached_images.create(filename=cache_filename)
return cache_filename
def get_image(self, *args, **kwargs):
as_base64 = kwargs.pop('as_base64', False)
transformations = kwargs.pop('transformations', [])
size = kwargs.pop('size', setting_display_size.value)
rotation = int(
kwargs.pop('rotation', DEFAULT_ROTATION) or DEFAULT_ROTATION)
zoom_level = int(
kwargs.pop('zoom', DEFAULT_ZOOM_LEVEL) or DEFAULT_ZOOM_LEVEL)
if zoom_level < setting_zoom_min_level.value:
zoom_level = setting_zoom_min_level.value
if zoom_level > setting_zoom_max_level.value:
zoom_level = setting_zoom_max_level.value
rotation = rotation % 360
cache_filename = self.cache_filename
logger.debug('Page cache filename: %s', cache_filename)
if cache_storage_backend.exists(cache_filename):
logger.debug('Page cache file "%s" found', cache_filename)
converter = converter_class(
file_object=cache_storage_backend.open(cache_filename))
converter.seek(0)
else:
logger.debug('Page cache file "%s" not found', cache_filename)
try:
converter = converter_class(
file_object=self.document_version.get_intermidiate_file())
converter.seek(page_number=self.page_number - 1)
page_image = converter.get_page()
with cache_storage_backend.open(cache_filename,
'wb+') as file_object:
file_object.write(page_image.getvalue())
except Exception as exception:
# Cleanup in case of error
logger.error('Error creating page cache file "%s"; %s',
cache_filename, exception)
cache_storage_backend.delete(cache_filename)
raise
# Stored transformations
for stored_transformation in Transformation.objects.get_for_model(
self, as_classes=True):
converter.transform(transformation=stored_transformation)
# Interactive transformations
for transformation in transformations:
converter.transform(transformation=transformation)
if rotation:
converter.transform(transformation=TransformationRotate(
degrees=rotation))
if size:
converter.transform(transformation=TransformationResize(
**dict(zip(('width', 'height'), (size.split('x'))))))
if zoom_level:
converter.transform(transformation=TransformationZoom(
percent=zoom_level))
page_image = converter.get_page()
if as_base64:
# TODO: don't prepend 'data:%s;base64,%s' part
return 'data:%s;base64,%s' % (
'image/png', base64.b64encode(page_image.getvalue()))
else:
return page_image