ImageHandler.py

"""
Macstodon - a Mastodon client for classic Mac OS


MIT License

Copyright (c) 2022-2024 Scott Small and Contributors

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit
persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the
Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
"""


# ##############
# Python Imports 
# ##############

import Image
import GifImagePlugin
import JpegImagePlugin
import PngImagePlugin
import os
import string
import sys
import urllib


# ###################
# Third-Party Imports
# ###################

from third_party.PixMapWrapper import PixMapWrapper


# ##########
# My Imports
# ##########

from MacstodonHelpers import dprint, getFilenameFromURL


# ###########
# Application
# ###########

class ImageHandler:

    def __init__(self, app):
        """
        Initializes the ImageHandler class.
        """
        self.app = app

    def getImageFromURL(self, url, imgtype=None):
        """
        Wrapper function - given an image URL, either downloads and caches
        the image, or loads it from the cache if it already exists there.
        """
        try:
            dprint("Want to cache image: %s" % imgtype)
            file_name = getFilenameFromURL(url)
            if not self.isCached(file_name):
                dprint("Image is not cached, downloading")
                self.downloadImage(url, file_name)
                dprint("Resizing image: %s" % imgtype)
                img = self.resizeAndGetImage(file_name, imgtype)
            else:
                dprint("Image is already cached")
                img = self.getImageFromCache(file_name)
            return img
        except:
            etype, evalue = sys.exc_info()[:2]
            dprint("Error loading image: %s: %s" % (etype, evalue))
            return None

    def isCached(self, file_name):
        """
        Checks if an image exists in cache or not and returns true/false.
        """
        cachepath = self.app.cachefolderpath
        try:
            os.stat(os.path.join(cachepath, file_name))
            return 1
        except:
            exc_info = sys.exc_info()
            if str(exc_info[0]) == "mac.error" and exc_info[1][0] == 2:
                return 0
            raise

    def getImageFromCache(self, file_name):
        """
        Loads an image file from the cache.
        """
        pm = PixMapWrapper()
        file_path = os.path.join(self.app.cachefolderpath, file_name)
        handle = open(file_path, "rb")
        pil_image = Image.open(handle, "r")
        pm.fromImage(pil_image)
        handle.close()
        del pil_image
        return pm

    def downloadImage(self, url, file_name=None):
        """
        Downloads an image from the given URL and writes it to the cache.
        """
        http_url = string.replace(url, "https://", "http://")
        file_path = os.path.join(self.app.cachefolderpath, file_name)
        urllib.urlretrieve(http_url, file_path)

    def resizeAndGetImage(self, file_name, imgtype):
        """
        Resizes an image to an appropriate size and overwrites the existing cached image.
        """
        file_path = os.path.join(self.app.cachefolderpath, file_name)
        handle = open(file_path, "rb")
        pil_image = Image.open(handle, "r")
        if imgtype == "account":
            pil_image_small = pil_image.resize((48, 48))
        elif imgtype == "banner":
            pil_image_small = pil_image.resize((384, 128))
        del pil_image
        handle.close()
        pil_image_small.save(file_path)
        pm = PixMapWrapper()
        pm.fromImage(pil_image_small)
        del pil_image_small
        return pm