Replace KFX (does not work) with KFX (Send to Kindle EPUB) (#1309)

* add better kfx output

* fix kfx res

* fix bug

* fix bug

* no errors

* kfx defaults to PNG

* KFX 200 MB default

* clarify send to kindle

* fit close images

* adjust

* refactor contain

* initial fixes

kindlecomicconverter/shared.py

@@ -61,6 +61,23 @@ def getImageFileName(imgfile):
     ext = ext.lower()
     return [name, ext]
 
+def get_contain_resolution(image, size):
+    '''same code as Pillow ImageOps.contain()'''
+    im_ratio = image.width / image.height
+    dest_ratio = size[0] / size[1]
+
+    if im_ratio != dest_ratio:
+        if im_ratio > dest_ratio:
+            new_height = round(image.height / image.width * size[0])
+            if new_height != size[1]:
+                size = (size[0], new_height)
+        else:
+            new_width = round(image.width / image.height * size[1])
+            if new_width != size[0]:
+                size = (new_width, size[1])
+    
+    return size
+
 
 def walkSort(dirnames, filenames):
     convert = lambda text: int(text) if text.isdigit() else text