add check logo exist

.gitignore

@@ -1,3 +1,5 @@
 venv/
 dist/
 assm/__pycache__
+images/
+logo.png

assm/__init__.py

@@ -1,3 +1,3 @@
 """iOS splash screen generator"""
 
-__version__ = "0.1.1"
+__version__ = "0.1.2"

assm/__main__.py

@@ -19,7 +19,14 @@ def make_splash_image(screen_orientation, screen_width, screen_height, logo_path
     splash_image = Image.new('RGB', (screen_width, screen_height), (255, 255, 255))
     logo_image = Image.open(logo_path)
     app_logo = logo_image.resize((logo_size, logo_size))
+    
+    try:
         splash_image.paste(app_logo, (logo_w_pos, logo_h_pos), app_logo)
+    except ValueError as e:
+        if str(e) == 'bad transparency mask':
+            print('ERROR: Bad transparency mask.')
+
+        quit(-1)
 
     return splash_image
 
@@ -42,10 +49,14 @@ def main(output_folder='./images/'):
             f=output_folder, w=device_w, h=device_h
         )
 
+        try:
             splash = make_splash_image('portrait', device_w, device_h, 'logo.png')
+        except FileNotFoundError as e:
+            print('ERROR: File logo.png not found.')
+            quit(1)
         splash.save(file_name)
 
-        print('..splash for {w}x{h} saved...'.format(w=device_w, h=device_h))
+        print('...splash for {w}x{h} saved...'.format(w=device_w, h=device_h))
 
     # landscape
     print('Generate landscape splash...')

pyproject.toml

@@ -7,24 +7,20 @@ module = "assm"
 author = "Alexander Popov"
 author-email = "iiiypuk@iiiypuk.me"
 home-page = "https://github.com/emilecok/assm"
-requires = ["Pillow==8.1.0" ]
+requires = ["Pillow==8.3.1" ]
 description-file = "README.md"
 classifiers = [
     "License :: OSI Approved :: MIT License",
     "Programming Language :: Python :: 3"
 ]
 requires-python = ">=3"
-keywords = [
-	"iOS",
-	"splashscreen",
-	"splash-screen"
-]
+keywords = "iOS,splashscreen,splash-screen"
 
 [tool.flit.metadata.requires-extra]
 dev = ["pylint == 2.7.1", "black == 20.8b1"]
 
 [tool.flit.metadata.urls]
-Documentation = ""
+Documentation = "https://docs/"
 
 [tool.black]
 line-length = 99