micropython · jimmo · Jan 2, 2018
diff --git a/docs/library/framebuf.rst b/docs/library/framebuf.rst
@@ -146,7 +146,18 @@ Constants
 
 .. data:: framebuf.RGB565
 
-    Red Green Blue (16-bit, 5+6+5) color format
+    Red Green Blue (16-bit, 5+6+5) device-endian color format
+    This will default to the device's native endianness (likely to be little-endian).
+
+.. data:: framebuf.RGB565_BE
+
+    Red Green Blue (16-bit, 5+6+5) big-endian color format
+    This will result in a pixel color value of `0xabcd` being stored in the buffer as `[0xab, 0xcd]`.
+
+.. data:: framebuf.RGB565_LE
+
+    Red Green Blue (16-bit, 5+6+5) little-endian color format
+    This will result in a pixel color value of `0xabcd` being stored in the buffer as `[0xcd, 0xab]`.
 
 .. data:: framebuf.GS2_HMSB
 

diff --git a/extmod/modframebuf.c b/extmod/modframebuf.c
@@ -27,6 +27,7 @@
 #include <stdio.h>
 #include <string.h>
 
+#include "py/binary.h"
 #include "py/runtime.h"
 
 #if MICROPY_PY_FRAMEBUF
@@ -52,13 +53,14 @@ typedef struct _mp_framebuf_p_t {
 } mp_framebuf_p_t;
 
 // constants for formats
-#define FRAMEBUF_MVLSB    (0)
-#define FRAMEBUF_RGB565   (1)
-#define FRAMEBUF_GS2_HMSB (5)
-#define FRAMEBUF_GS4_HMSB (2)
-#define FRAMEBUF_GS8      (6)
-#define FRAMEBUF_MHLSB    (3)
-#define FRAMEBUF_MHMSB    (4)
+#define FRAMEBUF_MVLSB     (0)
+#define FRAMEBUF_RGB565_BE (1)
+#define FRAMEBUF_RGB565_LE (7)
+#define FRAMEBUF_GS2_HMSB  (5)
+#define FRAMEBUF_GS4_HMSB  (2)
+#define FRAMEBUF_GS8       (6)
+#define FRAMEBUF_MHLSB     (3)
+#define FRAMEBUF_MHMSB     (4)
 
 // Functions for MHLSB and MHMSB
 
@@ -114,16 +116,27 @@ STATIC void mvlsb_fill_rect(const mp_obj_framebuf_t *fb, int x, int y, int w, in
 
 // Functions for RGB565 format
 
+STATIC void rgb565_flip_endian(uint32_t* col, uint8_t format) {
+    if ((MP_ENDIANNESS_LITTLE && format == FRAMEBUF_RGB565_BE) || (MP_ENDIANNESS_BIG && format == FRAMEBUF_RGB565_LE)) {
+        *col = ((*col & 0xff) << 8) | ((*col >> 8) & 0xff);
+    }
+}
+
 STATIC void rgb565_setpixel(const mp_obj_framebuf_t *fb, int x, int y, uint32_t col) {
+    rgb565_flip_endian(&col, fb->format);
     ((uint16_t*)fb->buf)[x + y * fb->stride] = col;
 }
 
 STATIC uint32_t rgb565_getpixel(const mp_obj_framebuf_t *fb, int x, int y) {
-    return ((uint16_t*)fb->buf)[x + y * fb->stride];
+    uint32_t col = ((uint16_t*)fb->buf)[x + y * fb->stride];
+    rgb565_flip_endian(&col, fb->format);
+    return col;
 }
 
 STATIC void rgb565_fill_rect(const mp_obj_framebuf_t *fb, int x, int y, int w, int h, uint32_t col) {
+    rgb565_flip_endian(&col, fb->format);
     uint16_t *b = &((uint16_t*)fb->buf)[x + y * fb->stride];
+
     while (h--) {
         for (int ww = w; ww; --ww) {
             *b++ = col;
@@ -228,14 +241,25 @@ STATIC void gs8_fill_rect(const mp_obj_framebuf_t *fb, int x, int y, int w, int
 
 STATIC mp_framebuf_p_t formats[] = {
     [FRAMEBUF_MVLSB] = {mvlsb_setpixel, mvlsb_getpixel, mvlsb_fill_rect},
-    [FRAMEBUF_RGB565] = {rgb565_setpixel, rgb565_getpixel, rgb565_fill_rect},
+    [FRAMEBUF_RGB565_BE] = {rgb565_setpixel, rgb565_getpixel, rgb565_fill_rect},
+    [FRAMEBUF_RGB565_LE] = {rgb565_setpixel, rgb565_getpixel, rgb565_fill_rect},
     [FRAMEBUF_GS2_HMSB] = {gs2_hmsb_setpixel, gs2_hmsb_getpixel, gs2_hmsb_fill_rect},
     [FRAMEBUF_GS4_HMSB] = {gs4_hmsb_setpixel, gs4_hmsb_getpixel, gs4_hmsb_fill_rect},
     [FRAMEBUF_GS8] = {gs8_setpixel, gs8_getpixel, gs8_fill_rect},
     [FRAMEBUF_MHLSB] = {mono_horiz_setpixel, mono_horiz_getpixel, mono_horiz_fill_rect},
     [FRAMEBUF_MHMSB] = {mono_horiz_setpixel, mono_horiz_getpixel, mono_horiz_fill_rect},
 };
 
+STATIC inline size_t bytes_per_pixel(const mp_obj_framebuf_t *fb) {
+    switch (fb->format) {
+        case FRAMEBUF_RGB565_BE:
+        case FRAMEBUF_RGB565_LE:
+            return 2;
+        default:
+            return 1;
+    }
+}
+
 static inline void setpixel(const mp_obj_framebuf_t *fb, int x, int y, uint32_t col) {
     formats[fb->format].setpixel(fb, x, y, col);
 }
@@ -281,7 +305,8 @@ STATIC mp_obj_t framebuf_make_new(const mp_obj_type_t *type, size_t n_args, size
 
     switch (o->format) {
         case FRAMEBUF_MVLSB:
-        case FRAMEBUF_RGB565:
+        case FRAMEBUF_RGB565_BE:
+        case FRAMEBUF_RGB565_LE:
             break;
         case FRAMEBUF_MHLSB:
         case FRAMEBUF_MHMSB:
@@ -306,7 +331,7 @@ STATIC mp_int_t framebuf_get_buffer(mp_obj_t self_in, mp_buffer_info_t *bufinfo,
     (void)flags;
     mp_obj_framebuf_t *self = MP_OBJ_TO_PTR(self_in);
     bufinfo->buf = self->buf;
-    bufinfo->len = self->stride * self->height * (self->format == FRAMEBUF_RGB565 ? 2 : 1);
+    bufinfo->len = self->stride * self->height * bytes_per_pixel(self);
     bufinfo->typecode = 'B'; // view framebuf as bytes
     return 0;
 }
@@ -630,7 +655,13 @@ STATIC const mp_rom_map_elem_t framebuf_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_FrameBuffer1), MP_ROM_PTR(&legacy_framebuffer1_obj) },
     { MP_ROM_QSTR(MP_QSTR_MVLSB), MP_ROM_INT(FRAMEBUF_MVLSB) },
     { MP_ROM_QSTR(MP_QSTR_MONO_VLSB), MP_ROM_INT(FRAMEBUF_MVLSB) },
-    { MP_ROM_QSTR(MP_QSTR_RGB565), MP_ROM_INT(FRAMEBUF_RGB565) },
+#if MP_ENDIANNESS_BIG
+    { MP_ROM_QSTR(MP_QSTR_RGB565), MP_ROM_INT(FRAMEBUF_RGB565_BE) },
+#else
+    { MP_ROM_QSTR(MP_QSTR_RGB565), MP_ROM_INT(FRAMEBUF_RGB565_LE) },
+#endif
+    { MP_ROM_QSTR(MP_QSTR_RGB565_BE), MP_ROM_INT(FRAMEBUF_RGB565_BE) },
+    { MP_ROM_QSTR(MP_QSTR_RGB565_LE), MP_ROM_INT(FRAMEBUF_RGB565_LE) },
     { MP_ROM_QSTR(MP_QSTR_GS2_HMSB), MP_ROM_INT(FRAMEBUF_GS2_HMSB) },
     { MP_ROM_QSTR(MP_QSTR_GS4_HMSB), MP_ROM_INT(FRAMEBUF_GS4_HMSB) },
     { MP_ROM_QSTR(MP_QSTR_GS8), MP_ROM_INT(FRAMEBUF_GS8) },

diff --git a/tests/extmod/framebuf16.py b/tests/extmod/framebuf16.py
@@ -4,56 +4,74 @@
     print("SKIP")
     raise SystemExit
 
-def printbuf():
+
+def printbuf(buf, w, h):
     print("--8<--")
     for y in range(h):
         print(buf[y * w * 2:(y + 1) * w * 2])
     print("-->8--")
 
-w = 4
-h = 5
-buf = bytearray(w * h * 2)
-fbuf = framebuf.FrameBuffer(buf, w, h, framebuf.RGB565)
-
-# fill
-fbuf.fill(0xffff)
-printbuf()
-fbuf.fill(0x0000)
-printbuf()
-
-# put pixel
-fbuf.pixel(0, 0, 0xeeee)
-fbuf.pixel(3, 0, 0xee00)
-fbuf.pixel(0, 4, 0x00ee)
-fbuf.pixel(3, 4, 0x0ee0)
-printbuf()
-
-# get pixel
-print(fbuf.pixel(0, 4), fbuf.pixel(1, 1))
-
-# scroll
-fbuf.fill(0x0000)
-fbuf.pixel(2, 2, 0xffff)
-printbuf()
-fbuf.scroll(0, 1)
-printbuf()
-fbuf.scroll(1, 0)
-printbuf()
-fbuf.scroll(-1, -2)
-printbuf()
-
-w2 = 2
-h2 = 3
-buf2 = bytearray(w2 * h2 * 2)
-fbuf2 = framebuf.FrameBuffer(buf2, w2, h2, framebuf.RGB565)
-
-fbuf2.fill(0x0000)
-fbuf2.pixel(0, 0, 0x0ee0)
-fbuf2.pixel(0, 2, 0xee00)
-fbuf2.pixel(1, 0, 0x00ee)
-fbuf2.pixel(1, 2, 0xe00e)
-fbuf.fill(0xffff)
-fbuf.blit(fbuf2, 3, 3, 0x0000)
-fbuf.blit(fbuf2, -1, -1, 0x0000)
-fbuf.blit(fbuf2, 16, 16, 0x0000)
-printbuf()
+
+def test_basic():
+    w = 4
+    h = 5
+    buf = bytearray(w * h * 2)
+    fbuf = framebuf.FrameBuffer(buf, w, h, framebuf.RGB565)
+
+    # fill
+    fbuf.fill(0xffff)
+    printbuf(buf, w, h)
+    fbuf.fill(0x0000)
+    printbuf(buf, w, h)
+
+    # put pixel
+    fbuf.pixel(0, 0, 0xeeee)
+    fbuf.pixel(3, 0, 0xee00)
+    fbuf.pixel(0, 4, 0x00ee)
+    fbuf.pixel(3, 4, 0x0ee0)
+    printbuf(buf, w, h)
+
+    # get pixel
+    print(fbuf.pixel(0, 4), fbuf.pixel(1, 1))
+
+    # scroll
+    fbuf.fill(0x0000)
+    fbuf.pixel(2, 2, 0xffff)
+    printbuf(buf, w, h)
+    fbuf.scroll(0, 1)
+    printbuf(buf, w, h)
+    fbuf.scroll(1, 0)
+    printbuf(buf, w, h)
+    fbuf.scroll(-1, -2)
+    printbuf(buf, w, h)
+
+    w2 = 2
+    h2 = 3
+    buf2 = bytearray(w2 * h2 * 2)
+    fbuf2 = framebuf.FrameBuffer(buf2, w2, h2, framebuf.RGB565)
+
+    fbuf2.fill(0x0000)
+    fbuf2.pixel(0, 0, 0x0ee0)
+    fbuf2.pixel(0, 2, 0xee00)
+    fbuf2.pixel(1, 0, 0x00ee)
+    fbuf2.pixel(1, 2, 0xe00e)
+    fbuf.fill(0xffff)
+    fbuf.blit(fbuf2, 3, 3, 0x0000)
+    fbuf.blit(fbuf2, -1, -1, 0x0000)
+    fbuf.blit(fbuf2, 16, 16, 0x0000)
+    printbuf(buf, w, h)
+
+
+def test_endian():
+    for endian in (framebuf.RGB565_BE, framebuf.RGB565_LE,):
+        w = 4
+        h = 4
+        buf = bytearray(w * h * 2)
+        fbuf = framebuf.FrameBuffer(buf, w, h, endian)
+        fbuf.fill_rect(1, 1, 2, 2, 0xabcd)
+        fbuf.pixel(2, 2, 0xdcba)
+        printbuf(buf, w, h)
+
+
+test_basic()
+test_endian()
diff --git a/tests/extmod/framebuf16.py.exp b/tests/extmod/framebuf16.py.exp
@@ -55,3 +55,15 @@ bytearray(b'\xff\xff\xff\xff\xff\xff\xff\xff')
 bytearray(b'\xff\xff\xff\xff\xff\xff\xe0\x0e')
 bytearray(b'\xff\xff\xff\xff\xff\xff\xff\xff')
 -->8--
+--8<--
+bytearray(b'\x00\x00\x00\x00\x00\x00\x00\x00')
+bytearray(b'\x00\x00\xab\xcd\xab\xcd\x00\x00')
+bytearray(b'\x00\x00\xab\xcd\xdc\xba\x00\x00')
+bytearray(b'\x00\x00\x00\x00\x00\x00\x00\x00')
+-->8--
+--8<--
+bytearray(b'\x00\x00\x00\x00\x00\x00\x00\x00')
+bytearray(b'\x00\x00\xcd\xab\xcd\xab\x00\x00')
+bytearray(b'\x00\x00\xcd\xab\xba\xdc\x00\x00')
+bytearray(b'\x00\x00\x00\x00\x00\x00\x00\x00')
+-->8--