extmod/modframebuf: Add support for blit'ing read-only data.

Currently the `FrameBuffer.blit(buf, x, y)` method requires the `buf`
argument to be another `FrameBuffer`, which is quite restrictive because it
doesn't allow blit'ing read-only memory/data.

This commit extends `blit()` to allow the `buf` argument to be a tuple or
list of the form:

    (buffer, width, height, format[, stride])

where `buffer` can be anything with the buffer protocol and may be
read-only, eg `bytes`.

Also, the palette argument to `blit()` may be of the same form.

The form of this tuple/list was chosen to be the same as the signature of
the `FrameBuffer` constructor (that saves quite a bit of code size doing it
that way).

Signed-off-by: Damien George <damien@micropython.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/examples/natmod/framebuf/framebuf.c b/examples/natmod/framebuf/framebuf.c
index 1ba702e33..5fd7c6be3 100644
--- a/examples/natmod/framebuf/framebuf.c
+++ b/examples/natmod/framebuf/framebuf.c
@@ -4,6 +4,9 @@
 #include "py/dynruntime.h"
 
 #if !defined(__linux__)
+void *memcpy(void *dst, const void *src, size_t n) {
+    return mp_fun_table.memmove_(dst, src, n);
+}
 void *memset(void *s, int c, size_t n) {
     return mp_fun_table.memset_(s, c, n);
 }