don't crop first page if its color (#1441)

kindlecomicconverter/comic2ebook.py

@@ -686,10 +686,13 @@ def imgDirectoryProcessing(path, job_progress=''):
     options.imgMetadata = {}
     work = []
     pagenumber = 0
+    is_first_page = True
     for dirpath, _, filenames in os.walk(path):
-        for afile in filenames:
+        for afile in os_sorted(filenames):
             pagenumber += 1
-            work.append([afile, dirpath, options])
+            work.append([afile, dirpath, options, is_first_page])
+            if is_first_page:
+                is_first_page = False
     if GUI:
         GUI.progressBarTick.emit(str(pagenumber))
     if len(work) > 0:
@@ -734,10 +737,14 @@ def imgFileProcessing(work):
         afile = work[0]
         dirpath = work[1]
         opt = work[2]
+        is_first_page = work[3]
         output = []
         workImg = image.ComicPageParser((dirpath, afile), opt)
         for i in workImg.payload:
             img = image.ComicPage(opt, *i)
+            if is_first_page and img.color:
+                pass
+            else:
                 if opt.cropping == 2 and not opt.webtoon:
                     img.cropPageNumber(opt.croppingp, opt.croppingm)
                 if opt.cropping == 1 and not opt.webtoon: