Add 4-cell mosaic graphics.

These follow the same approach as 6-cell graphics: the smoothing
algorithm is disabled and there's no margin between character cells.
This is necessary to ensure that "upblock" and "dnblock" harmonise
with "lfblock" and "rtblock", the latter two being unified with 6-cell
graphics and the former not.

I've filled in the rest of the 4-cell characters on the basis that an
alternate history in which Teletext used 4-cell rather than 6-cell
graphics is perfectly plausible and Bedstead may as well support it.

diff --git a/bedstead.c b/bedstead.c
index 5a84cc2dd3f2f7c9ea6ffe3c72ee1bea2da8d3b7..c69fa90d7b0e46008f999459ee3bc0dca49147e4 100644 (file)
--- a/bedstead.c
+++ b/bedstead.c
@@ -217,6 +217,7 @@ static void doprologue(void);
 static void dochar(char const data[YSIZE], unsigned flags);
 static void dochar_plotter(char const data[YSIZE], unsigned flags);
 static void domosaic(unsigned code, bool sep);
+static void domosaic4(unsigned code);
 static void dopanose(void);
 static void glyph_complement(void);
 
@@ -225,8 +226,9 @@ static struct glyph {
        int unicode;
        char const *name;
        unsigned int flags;
-#define SC  0x01 /* Character has a small-caps variant. */
-#define MOS 0x02 /* Mosaic graphics character */
+#define SC   0x01 /* Character has a small-caps variant. */
+#define MOS  0x02 /* Mosaic graphics character */
+#define MOS4 0x04 /* 4-cell mosaic graphics character */
 } const glyphs[] = {
  /*
   * The first batch of glyphs comes from the code tables at the end of
@@ -1333,14 +1335,17 @@ static struct glyph {
  {{012,012,012,033,000,033,012,012,012}, 0x256c, "SF440000" },
 
  /* Block elements */
- {{037,037,037,037,037,000,000,000,000}, 0x2580, "upblock" },
- {{000,000,000,000,037,037,037,037,037}, 0x2584, "dnblock" },
+ {{ 3},   0x2580, "upblock", MOS4 }, {{12},   0x2584, "dnblock", MOS4 },
  {{0x5f}, 0x2588, "block",   MOS },
- {{0x15}, 0x258c, "lfblock", MOS },
- {{0x4a}, 0x2590, "rtblock", MOS },
+ {{0x15}, 0x258c, "lfblock", MOS }, {{0x4a}, 0x2590, "rtblock", MOS },
  {{025,000,012,000,025,000,012,000,025}, 0x2591, "ltshade" },
  {{022,011,004,022,011,004,022,011,004}, 0x2592, "shade" },
  {{025,037,012,037,025,037,012,037,025}, 0x2593, "dkshade" },
+ {{ 4},   0x2596, NULL, MOS4 }, {{ 8},   0x2597, NULL, MOS4 },
+ {{ 1},   0x2598, NULL, MOS4 }, {{13},   0x2599, NULL, MOS4 },
+ {{ 9},   0x259a, NULL, MOS4 }, {{ 7},   0x259b, NULL, MOS4 },
+ {{11},   0x259c, NULL, MOS4 }, {{ 2},   0x259d, NULL, MOS4 },
+ {{ 6},   0x259e, NULL, MOS4 }, {{14},   0x259f, NULL, MOS4 },
 
  /* Geometric shapes */
  {{037,021,021,021,021,021,037,000,000}, 0x25a1, "H22073" },
@@ -1795,6 +1800,8 @@ main(int argc, char **argv)
                if (glyphs[i].flags & MOS)
                        domosaic(glyphs[i].data[0],
                                 (glyphs[i].data[0] & 0x20) != 0);
+               else if (glyphs[i].flags & MOS4)
+                       domosaic4(glyphs[i].data[0]);
                else {
                        if (plottermode)
                                dochar_plotter(glyphs[i].data, glyphs[i].flags);
@@ -2505,6 +2512,19 @@ domosaic(unsigned code, bool sep)
        emit_path();
 }
 
+static void
+domosaic4(unsigned code)
+{
+
+       clearpath();
+       if (code & 1) tile(0, 6, 3, 11);
+       if (code & 2) tile(3, 6, 6, 11);
+       if (code & 4) tile(0, 1, 3, 6);
+       if (code & 8) tile(3, 1, 6, 6);
+       clean_path();
+       emit_path();
+}
+
 static int
 byunicode(const void *va, const void *vb)
 {