Closes #210

Signed-off-by: Rahix <rahix@rahix.de>

Signed-off-by: Rahix <rahix@rahix.de>

It's 44 years since the release of vi and sadly lots of editors still
don't care about trimming off trailing spaces ...
Signed-off-by: Rahix <rahix@rahix.de>

This allows to read and write strings to the config file.

Instead of an ugly hack where spaces are used to pad the entries
background colors, properly draw a rectangle and the text above
it.  No visual change.
Signed-off-by: Rahix <rahix@rahix.de>

Signed-off-by: Rahix <rahix@rahix.de>

Fix all warnings in pycardium/modules.
Signed-off-by: Rahix <rahix@rahix.de>

Implement the hal functions necessary for utime.ticks_ms() and
utime.ticks_us().  This enables much more accurate measurements of time
taken in Pycardium (useful for profiling).

Please note that the tick counter will reset whenever a new app is
loaded.
Signed-off-by: Rahix <rahix@rahix.de>

Allow calling buttons.read() without an argument.  This is equivalent to
a mask with all bits set (that is, buttons.read(255)).  Additionally,
add a check that the mask is within the limits (< 256).
Signed-off-by: Rahix <rahix@rahix.de>

For convenience, allow calling os.listdir() without any argument.
This is equivalent to calling os.listdir("").
Signed-off-by: Rahix <rahix@rahix.de>

Philip Stewart authored Oct 05, 2019 and Rahix committed Oct 05, 2019

Fix two bugs in the display/gfx module:

1. The animation of the simple_menu used in the main menu had the issue
   that there is a black line visible at the top.  This is due the
   gfx_puts method ignoring lines, where the top pixel of the string is
   above the top of the screen.  As gfx_puts uses gfx_setpixel which in
   turn ignores pixels outside of the screen, remove the check in
   gfx_puts.
2. X and Y coordinates were cast to unsigned-ints before being given to
   the gfx-library which means calls like circ(0, -10, 30) would be draw
   at coordinates like [0,65526].  Fix this by changing the data-type of
   all coordinates to signed-integers.

Also remove the x and y ranges from the documentation of the individual
python functions and instead add a general documentation about the
screen and it's size/coordinate system.

Signed-off-by: Rahix <rahix@rahix.de>