extmod/modframebuf: Add 8-bit greyscale format (GS8).

dpgeorge · dpgeorge · commit 46b35356e172 · 2017-12-14T17:36:13.000+11:00
diff --git a/docs/library/framebuf.rst b/docs/library/framebuf.rst
@@ -155,3 +155,7 @@ Constants
 .. data:: framebuf.GS4_HMSB
 
     Grayscale (4-bit) color format
+
+.. data:: framebuf.GS8
+
+    Grayscale (8-bit) color format
diff --git a/extmod/modframebuf.c b/extmod/modframebuf.c
@@ -56,6 +56,7 @@ typedef struct _mp_framebuf_p_t {
 #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)
 
@@ -206,11 +207,31 @@ STATIC void gs4_hmsb_fill_rect(const mp_obj_framebuf_t *fb, int x, int y, int w,
     }
 }
 
+// Functions for GS8 format
+
+STATIC void gs8_setpixel(const mp_obj_framebuf_t *fb, int x, int y, uint32_t col) {
+    uint8_t *pixel = &((uint8_t*)fb->buf)[(x + y * fb->stride)];
+    *pixel = col & 0xff;
+}
+
+STATIC uint32_t gs8_getpixel(const mp_obj_framebuf_t *fb, int x, int y) {
+    return ((uint8_t*)fb->buf)[(x + y * fb->stride)];
+}
+
+STATIC void gs8_fill_rect(const mp_obj_framebuf_t *fb, int x, int y, int w, int h, uint32_t col) {
+    uint8_t *pixel = &((uint8_t*)fb->buf)[(x + y * fb->stride)];
+    while (h--) {
+        memset(pixel, col, w);
+        pixel += fb->stride;
+    }
+}
+
 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_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},
 };
@@ -272,6 +293,8 @@ STATIC mp_obj_t framebuf_make_new(const mp_obj_type_t *type, size_t n_args, size
         case FRAMEBUF_GS4_HMSB:
             o->stride = (o->stride + 1) & ~1;
             break;
+        case FRAMEBUF_GS8:
+            break;
         default:
             mp_raise_ValueError("invalid format");
     }
@@ -610,6 +633,7 @@ STATIC const mp_rom_map_elem_t framebuf_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_RGB565), MP_ROM_INT(FRAMEBUF_RGB565) },
     { 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) },
     { MP_ROM_QSTR(MP_QSTR_MONO_HLSB), MP_ROM_INT(FRAMEBUF_MHLSB) },
     { MP_ROM_QSTR(MP_QSTR_MONO_HMSB), MP_ROM_INT(FRAMEBUF_MHMSB) },
 };
diff --git a/tests/extmod/framebuf8.py b/tests/extmod/framebuf8.py
@@ -0,0 +1,32 @@
+try:
+    import framebuf
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+def printbuf():
+    print("--8<--")
+    for y in range(h):
+        for x in range(w):
+            print('%02x' % buf[(x + y * w)], end='')
+        print()
+    print("-->8--")
+
+w = 8
+h = 5
+buf = bytearray(w * h)
+fbuf = framebuf.FrameBuffer(buf, w, h, framebuf.GS8)
+
+# fill
+fbuf.fill(0x55)
+printbuf()
+
+# put pixel
+fbuf.pixel(0, 0, 0x11)
+fbuf.pixel(w - 1, 0, 0x22)
+fbuf.pixel(0, h - 1, 0x33)
+fbuf.pixel(w - 1, h - 1, 0xff)
+printbuf()
+
+# get pixel
+print(hex(fbuf.pixel(0, h - 1)), hex(fbuf.pixel(1, 1)))
diff --git a/tests/extmod/framebuf8.py.exp b/tests/extmod/framebuf8.py.exp
@@ -0,0 +1,15 @@
+--8<--
+5555555555555555
+5555555555555555
+5555555555555555
+5555555555555555
+5555555555555555
+-->8--
+--8<--
+1155555555555522
+5555555555555555
+5555555555555555
+5555555555555555
+33555555555555ff
+-->8--
+0x33 0x55
