def _read_metadata(handle):
block_count = lib.heif_image_handle_get_number_of_metadata_blocks(
handle, ffi.NULL)
if block_count == 0:
return
metadata = []
ids = ffi.new('heif_item_id[]', block_count)
lib.heif_image_handle_get_list_of_metadata_block_IDs(
handle, ffi.NULL, ids, block_count)
for i in range(len(ids)):
metadata_type = lib.heif_image_handle_get_metadata_type(handle, ids[i])
metadata_type = ffi.string(metadata_type).decode()
data_length = lib.heif_image_handle_get_metadata_size(handle, ids[i])
p_data = ffi.new('char[]', data_length)
error = lib.heif_image_handle_get_metadata(handle, ids[i], p_data)
if error.code != 0:
raise HeifError(code=error.code,
subcode=error.subcode,
message=ffi.string(error.message).decode())
data_buffer = ffi.buffer(p_data, data_length)
data = bytes(data_buffer)
if metadata_type == 'Exif':
# skip TIFF header, first 4 bytes
data = data[4:]
metadata.append({'type': metadata_type, 'data': data})
return metadata
def _read_heif_image(img, height):
p_stride = ffi.new('int *')
p_data = lib.heif_image_get_plane_readonly(img, heif_channel_interleaved,
p_stride)
stride = p_stride[0]
data_length = height * stride
data_buffer = ffi.buffer(p_data, data_length)
data = bytes(data_buffer)
return data
def _read_heif_context(ctx, d, apply_transformations):
error = lib.heif_context_read_from_memory(ctx, d, len(d), ffi.NULL)
if error.code != 0:
raise HeifError(code=error.code,
subcode=error.subcode,
message=ffi.string(error.message).decode())
p_handle = ffi.new('struct heif_image_handle **')
error = lib.heif_context_get_primary_image_handle(ctx, p_handle)
if error.code != 0:
raise HeifError(code=error.code,
subcode=error.subcode,
message=ffi.string(error.message).decode())
handle = p_handle[0]
try:
result = _read_heif_handle(handle, apply_transformations)
except:
raise
finally:
lib.heif_image_handle_release(handle)
return result
def _read_heif_handle(handle, apply_transformations):
alpha = lib.heif_image_handle_has_alpha_channel(handle)
mode = 'RGB' if alpha == 0 else 'RGBA'
p_img = ffi.new('struct heif_image **')
p_options = lib.heif_decoding_options_alloc()
if apply_transformations == False:
p_options.ignore_transformations = 1
error = lib.heif_decode_image(
handle, p_img, heif_colorspace_RGB, heif_chroma_interleaved_RGB
if mode == 'RGB' else heif_chroma_interleaved_RGBA, p_options)
lib.heif_decoding_options_free(p_options)
if error.code != 0:
raise HeifError(code=error.code,
subcode=error.subcode,
message=ffi.string(error.message).decode())
img = p_img[0]
width = lib.heif_image_handle_get_width(handle)
height = lib.heif_image_handle_get_height(handle)
size = (width, height)
try:
data = _read_heif_image(img, height)
except:
raise
finally:
lib.heif_image_release(img)
metadata = _read_metadata(handle)
color_profile = _read_color_profile(handle)
heif_file = HeifFile(mode=mode,
size=size,
data=data,
metadata=metadata,
color_profile=color_profile)
return heif_file
def _read_color_profile(handle):
profile_type = lib.heif_image_handle_get_color_profile_type(handle)
if profile_type == heif_color_profile_type_not_present:
return
color_profile = {'type': 'unknown', 'data': None}
if profile_type == heif_color_profile_type_nclx:
color_profile['type'] = 'nclx'
elif profile_type == heif_color_profile_type_rICC:
color_profile['type'] = 'rICC'
elif profile_type == heif_color_profile_type_prof:
color_profile['type'] = 'prof'
data_length = lib.heif_image_handle_get_raw_color_profile_size(handle)
p_data = ffi.new('char[]', data_length)
error = lib.heif_image_handle_get_raw_color_profile(handle, p_data)
if error.code != 0:
raise HeifError(code=error.code,
subcode=error.subcode,
message=ffi.string(error.message).decode())
data_buffer = ffi.buffer(p_data, data_length)
data = bytes(data_buffer)
color_profile['data'] = data
return color_profile