Add gallery app

Signed-off-by: Francesco Gazzetta <fgaz@fgaz.me>

README.rst

@@ -153,6 +153,10 @@ simulator:
    :alt: Small application for disabling bluetooth to save power and enhance security
    :width: 179
 
+.. image:: res/GalleryApp.png
+   :alt: Gallery application running on the wasp-os simulator
+   :width: 179
+
 .. image:: res/HeartApp.png
    :alt: Heart rate application running on the wasp-os simulator
    :width: 179

apps/Gallery.py

@@ -0,0 +1,113 @@
+# SPDX-License-Identifier: LGPL-3.0-or-later
+# Copyright (C) 2021 Francesco Gazzetta
+
+"""Image gallery
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+An application that shows images stored in the filesystem.
+
+.. figure:: res/GalleryApp.png
+    :width: 179
+
+Only 240x240 images are supported for now.
+The images have to be uploaded in the gallery directory.
+The images have to be encoded as raw RGB565 data in big endian byte order.
+To encode them, you can use ffmpeg:
+
+.. code-block:: sh
+
+    ffmpeg -vcodec png -i my_image.png -vcodec rawvideo -f rawvideo -pix_fmt rgb565be my_image.rgb565
+
+And to upload:
+
+.. code-block:: sh
+
+    ./tools/wasptool --binary --upload my_image.rgb565 --as gallery/my_image
+"""
+
+import wasp
+import icons
+
+class GalleryApp():
+    NAME = 'Gallery'
+    # 2-bit RLE, 96x64, generated from res/gallery_icon.png, 370 bytes
+    ICON = (
+        b'\x02'
+        b'`@'
+        b'\x1e@\x81d<d<d;f?X\xec2\xf0/'
+        b'\xf2-\xf4,\xc3.\xc3,\xc3.\xc3,\xc3.\xc3,'
+        b'\xc3.\xc3,\xc3\x04\x80\x1d\xa6\x04\xc3,\xc3\x04\xa6\x04'
+        b'\xc3,\xc3\x04\x83\xc0\xd2\xc2\xa1\x04@\xd7C,C\x04'
+        b'\x82\xc4\xa0\x04C,C\x04\x81\xc6\x9f\x04C,C\x04'
+        b'\x82\xc4\xa0\x04C,C\x04\x83\xc2\x9c\x80\xc1\x81\xc0\x1d'
+        b'\xc4\x04C,C\x04\xe0\x83\xc3\x04C,C\x04\xdf\x85'
+        b'\xc2\x04C,C\x04\xde\x87\xc1\x04C,C\x04\xdd\x89'
+        b'\x04C,C\x04\xdc\x8a\x04C,C\x04\xce\x82\xcb\x8b'
+        b'\x04C,C\x04\xcc\x85\xc9\x8c\x04C+D\x04\xca\x89'
+        b'\xc6\x8d\x04C*E\x04\xc8\x8d\xc3\x8e\x04C*E\x04'
+        b'\xc6\x91\xc2\x8d\x04C*E\x04\xc4\x95\xc2\x8b\x04C*'
+        b'E\x04\xc2\x99\xc2\x89\x04C*E\x04\xa6\x04C*E'
+        b'\x04\xa6\x04C*E\x04\xa6\x04C+D\x04\xa6\x04C'
+        b',C\x04\xa6\x04C,C\x04\x86@CB\x9bC\x04'
+        b'\x80\xd7\x83,\x83\x04\xc0\xc1\xc2I\xd5F\x04\x83,\x83'
+        b'\x04\xc1L\xcfJ\x04\x83,\x83\x04P\xc7O\x04\x83,'
+        b'\x83\x04f\x04\x83,\x83\x04f\x04\x83,\x83\x04f\x04'
+        b'\x83,\x83\x04f\x04\x83,\x83\x04f\x04\x83,\x83\x04'
+        b'f\x04\x83,\x83\x04f\x04\x83,\x83\x04f\x04\x83,'
+        b'\x83\x04f\x04\x83,\x83\x04f\x04\x83,\x83.\x83,'
+        b'\x83.\x83,\x83.\x83,\x83.\x83,\xb4-\xb2/'
+        b'\xb02\xac?X@\x81f;d<d<d\x1e'
+    )
+
+    def foreground(self):
+        try:
+            self.files = wasp.watch.os.listdir("gallery")
+        except FileNotFoundError:
+            self.files = []
+        # In case some images were deleted, we reset the index every time
+        self.index = 0
+        self._draw()
+        wasp.system.request_event(wasp.EventMask.SWIPE_LEFTRIGHT)
+
+    def background(self):
+        # We will read the contents of gallery again on foreground(),
+        # so let's free some memory
+        self.files = []
+
+    def swipe(self, event):
+        if event[0] == wasp.EventType.LEFT:
+            increment = 1
+        elif event[0] == wasp.EventType.RIGHT:
+            increment = -1
+        else:
+            increment = 0
+        self.index = (self.index + increment) % len(self.files)
+        self._draw()
+
+    def _draw(self):
+        draw = wasp.watch.drawable
+        draw.fill()
+        if not self.files:
+            draw.string('No files', 0, 60, width=240)
+            draw.string('in gallery/', 0, 98, width=240)
+        else:
+            filename = self.files[self.index]
+            # The file name will only show until the image overwrites it,
+            # so let's put it at the bottom so the user has a chance to see it
+            draw.string(filename[:(draw.wrap(filename, 240)[1])], 0, 200)
+            file = open("gallery/{}".format(filename), "rb")
+            display = wasp.watch.display
+            display.set_window(0, 0, 240, 240)
+
+            # We don't have enough memory to load the entire image at once, so
+            # we stream it from flash memory to the display
+            #TODO: why can't we do it in a single quick write session?
+            #display.quick_start()
+            buf = display.linebuffer[:2*240]
+            read = 1
+            while read > 0:
+                read = file.readinto(buf)
+                #display.quick_write(buf)
+                display.write_data(buf)
+            #display.quick_end()
+            file.close()

docs/apps.rst

@@ -53,6 +53,8 @@ Applications
 
 .. automodule:: apps.flashlight
 
+.. automodule:: Gallery
+
 .. automodule:: apps.haiku
 
 .. automodule:: Morse