pylib/gfxprim/generators/core/gen_blit.py

   1 # Module generating C source and headers for various PixelTypes
   2 # - submodule for blit and friends
   3 # 2011 - Tomas Gavenciak <gavento@ucw.cz>
   4
   5 from gfxprim.generators.utils import *
   6
   7 ## all generated direct blits, for generating GP_Blit() and others
   8 generated_blits = []
   9
  10 # TODO: adapt for both bit-endianness (in-byte prefix and suffix)
  11 # WARN: assuming little-endian in sub-byte pixels order (probably)
  12 def gen_blit_same_t(size, size_suffix, header, code):
  13   "Generate a function blitting the same type of pixel."
  14   "Only depends on bpp (bit size), size_suffix must be"
  15   "of form 8BPP, 2BPP_LE and the like."
  16
  17   header.rbody(
  18     "\n/*** Blit preserving type, variant for {{ size_suffix }} ***\n"
  19     " * Assumes the contexts to be of the right types and sizes\n"
  20     " * Ignores transformations and clipping */\n\n"
  21     "void GP_Blit_{{ size_suffix }}(const GP_Context *c1, GP_Coord x1, GP_Coord y1, GP_Size w, GP_Size h,\n"
  22     "                   GP_Context *c2, GP_Coord x2, GP_Coord y2);\n",
  23     size=size, size_suffix=size_suffix)
  24
  25   code.rbody(
  26     "\n/*** Blit preservimg type, variant for {{ size_suffix }} ***/\n"
  27     "void GP_Blit_{{ size_suffix }}(const GP_Context *c1, GP_Coord x1, GP_Coord y1, GP_Size w, GP_Size h,\n"
  28     "                   GP_Context *c2, GP_Coord x2, GP_Coord y2)\n"
  29     "{\n"
  30     "   if (unlikely(w == 0 || h == 0)) return;\n\n"
  31     "   /* Special case - copy whole line-block with one memcpy() */\n"
  32     "   if ((x1 == 0) && (x2 == 0) && (w == c1->w) && (c1->w == c2->w) &&\n"
  33     "           (c1->bytes_per_row == c2->bytes_per_row)) {\n"
  34     "           memcpy(c2->pixels + c2->bytes_per_row * y2,\n"
  35     "                  c1->pixels + c1->bytes_per_row * y1,\n"
  36     "                  c1->bytes_per_row * h);\n"
  37     "           return;\n"
  38     "   }\n\n"
  39     "{% if size>=8 %}"
  40     "   /* General case - memcpy() each horizontal line */\n"
  41     "   for (GP_Size i = 0; i < h; i++)\n"
  42     "           memcpy(GP_PIXEL_ADDR_{{ size_suffix }}(c2, x2, y2 + i), \n"
  43     "                  GP_PIXEL_ADDR_{{ size_suffix }}(c1, x2, y2 + i),\n"
  44     "                  {{ size/8 }} * w);\n"
  45     "{% else %}" # subtle - rectangles may not be byte aligned in the same way
  46     "   /* Alignment (index) of first bits in the first byte */\n"
  47     "   int al1 = GP_PIXEL_ADDR_OFFSET_{{ size_suffix }}(x1);\n"
  48     "   int al2 = GP_PIXEL_ADDR_OFFSET_{{ size_suffix }}(x2);\n"
  49     "   /* Special case of the same alignment and width >=2 bytes */\n"
  50     "   if ((al1 == al2) && (w * {{ size }} >= 16)) {\n"
  51     "           /* Number of bits in the last partial byte */\n"
  52     "           int end_al = GP_PIXEL_ADDR_OFFSET_{{ size_suffix }}(x1 + w);\n"
  53     "           GP_ASSERT(({{ size }} * w - al1 - end_al) % 8 == 0);\n"
  54     "           int copy_size = ({{ size }} * w - al1 - end_al) / 8;\n"
  55     "           /* First and last byte incident to the line */\n"
  56     "           uint8_t *p1 = GP_PIXEL_ADDR_{{ size_suffix }}(c1, x1, y1);\n"
  57     "           uint8_t *p2 = GP_PIXEL_ADDR_{{ size_suffix }}(c2, x2, y2);\n"
  58     "           uint8_t *end_p1 = GP_PIXEL_ADDR_{{ size_suffix }}(c1, x1 + w - 1, y1);\n"
  59     "           uint8_t *end_p2 = GP_PIXEL_ADDR_{{ size_suffix }}(c2, x2 + w - 1, y2);\n"
  60     "           for (GP_Size i = 0; i < h; i++) {\n"
  61     "                   if (al1 != 0)\n"
  62     "                           GP_SET_BITS(al1, 8-al1, *p2, GP_GET_BITS(al1, 8-al1, *p1));\n"
  63     "                   memcpy(p2+(al1!=0), p1+(al1!=0), copy_size);\n"
  64     "                   if (end_al != 0)\n"
  65     "                           GP_SET_BITS(0, end_al, *end_p2, GP_GET_BITS(0, end_al, *end_p1));\n"
  66     "                   p1 += c1->bytes_per_row;\n"
  67     "                   end_p1 += c1->bytes_per_row;\n"
  68     "                   p2 += c2->bytes_per_row;\n"
  69     "                   end_p2 += c2->bytes_per_row;\n"
  70     "           }\n"
  71     "   } else /* Different bit-alignment, can't use memcpy() */\n"
  72     "           GP_Blit_Naive(c1, x1, y1, w, h, c2, x2, y2);\n"
  73     "{% endif %}"
  74     "}\n", size=size, size_suffix=size_suffix)
  75