Draw the TUI's cells as pixels with the symbols' glyphs

vega pixels runs the same scripts as tui --dump and writes each frame as
an image: the view's cells (only those on screen are evaluated) become
glyphs, each drawn once per size with the exact area of its curves, in its
tone's colour on its row's background. No page, no scene in between. A
1920x1350 grid takes 12 ms a frame here, writing the image included.

Symbol files carry the font's line now (format 3: ascent and descent where
format 2 kept zeros), the cell height and baseline; and the build tool takes
fonts in order, later ones filling the codes earlier ones lack: a CJK font
alone drew ambiguous-width arrows two cells wide in a one-cell grid, which
the new check caught, so a monospace Latin font comes first and Hangul after.

1 files changed, 74 insertions, 7 deletions

diff --git a/surfaces/main.c b/surfaces/main.c
index 82131ab..d00bca6 100644
--- a/surfaces/main.c
+++ b/surfaces/main.c
@@ -20,6 +20,9 @@
  *   say              sentences (the first natural-language surface), driven by a script
  *   web [--listen ADDRESS] [--port N]
  *                    a web page (a GUI), on 127.0.0.1 unless another address is given
+ *   pixels --symbols FONT.vsym [--size PX] --grid WxH --out PREFIX
+ *                    the TUI's frames drawn with a font's glyphs, driven by a
+ *                    script: each show writes PREFIX-N.ppm after the text
  * With --store the app's states live in that tree store: the app continues
  * where it was, whichever surface runs it. With --watch (tui, web) a module
  * written again replaces the running one and states keep their values by
@@ -456,15 +459,45 @@ static int interactive(void) {
 
 /* ---- scripts -------------------------------------------------------- */
 
-typedef enum { SURFACE_CLI, SURFACE_SAY, SURFACE_TUI, SURFACE_WEB } Surface;
+typedef enum { SURFACE_CLI, SURFACE_SAY, SURFACE_TUI, SURFACE_WEB, SURFACE_PIXELS } Surface;
+
+/* The pixel surface's font and where its frames go. */
+static VegaFace face;
+static const char *frames_prefix;
+static unsigned frames;
+
+/* A frame as a binary PPM (P6): prefix-N.ppm. */
+static bool write_frame(const VegaGrid *grid, char path[512]) {
+    int width = (int)grid->width * face.cell_width, height = (int)grid->height * face.cell_height;
+    uint32_t *pixels = malloc((size_t)width * (size_t)height * sizeof(*pixels));
+    unsigned char *bytes = malloc((size_t)width * (size_t)height * 3);
+    bool ok = pixels && bytes;
+    if (ok) {
+        vega_pixels(grid, &face, pixels, (size_t)width);
+        for (size_t i = 0; i < (size_t)width * (size_t)height; ++i) {
+            bytes[3 * i] = (unsigned char)(pixels[i] >> 16);
+            bytes[3 * i + 1] = (unsigned char)(pixels[i] >> 8);
+            bytes[3 * i + 2] = (unsigned char)pixels[i];
+        }
+        snprintf(path, 512, "%s-%u.ppm", frames_prefix, ++frames);
+        FILE *f = fopen(path, "wb");
+        ok = f && fprintf(f, "P6\n%d %d\n255\n", width, height) > 0 &&
+             fwrite(bytes, 3, (size_t)width * (size_t)height, f) == (size_t)width * (size_t)height;
+        if (f && fclose(f)) ok = false;
+    }
+    free(pixels);
+    free(bytes);
+    return ok;
+}
 
 /* painting: show writes the terminal bytes of the frame, not the grid. */
 static int script(Surface surface, unsigned width, unsigned height, bool painting) {
     static char line[1 << 16];
     VegaGrid grid = {0};
-    if (surface == SURFACE_TUI && !vega_grid(&grid, width, height)) return 2;
+    bool gridded = surface == SURFACE_TUI || surface == SURFACE_PIXELS;
+    if (gridded && !vega_grid(&grid, width, height)) return 2;
     bool shown = false;
-    drawn = surface == SURFACE_TUI ? &grid : NULL;
+    drawn = gridded ? &grid : NULL;
     bool color = surface == SURFACE_CLI && isatty(STDOUT_FILENO) && !getenv("NO_COLOR");
     unsigned long counted = vega_evaluations();
     while (fgets(line, sizeof(line), stdin)) {
@@ -498,7 +531,7 @@ static int script(Surface surface, unsigned width, unsigned height, bool paintin
         } else if (!strcmp(command, "click")) {
             unsigned at_line = 0, at_column = 0;
             verb = "point";
-            if (surface != SURFACE_TUI) { fputs("vega: click needs the tui\n", stderr); continue; }
+            if (!gridded) { fputs("vega: click needs the tui or pixels\n", stderr); continue; }
             acted = sscanf(line, "%*s %u %u", &at_line, &at_column) == 2 && at_line && shown;
             ok = acted && mouse(0, at_line - 1);
         } else if (!strcmp(command, "time")) {
@@ -538,6 +571,11 @@ static int script(Surface surface, unsigned width, unsigned height, bool paintin
                 vega_draw(&grid, &app, &screen, entry, entry_length, typing);
                 dump(&grid);
                 printf("cells %lu\n", vega_evaluations() - counted);
+                char path[512];
+                if (surface == SURFACE_PIXELS) {
+                    if (!write_frame(&grid, path)) { fprintf(stderr, "vega: cannot write %s\n", path); return 1; }
+                    printf("frame %s %dx%d\n", path, (int)grid.width * face.cell_width, (int)grid.height * face.cell_height);
+                }
             }
             counted = vega_evaluations();
         } else {
@@ -556,8 +594,28 @@ static int script(Surface surface, unsigned width, unsigned height, bool paintin
     return 0;
 }
 
+/* The symbols a pixel surface draws with, read whole and kept. */
+static bool open_face(const char *path, float size) {
+    static VegaSymbols symbols;
+    FILE *f = fopen(path, "rb");
+    long length = f && !fseek(f, 0, SEEK_END) ? ftell(f) : -1;
+    unsigned char *bytes = length > 0 && !fseek(f, 0, SEEK_SET) ? malloc((size_t)length) : NULL;
+    bool ok = bytes && fread(bytes, 1, (size_t)length, f) == (size_t)length;
+    if (f) fclose(f);
+    char error[128] = "cannot read it";
+    ok = ok && vega_symbols_open(&symbols, bytes, (size_t)length, error, sizeof(error));
+    if (ok && !vega_face_open(&face, &symbols, size)) {
+        ok = false;
+        snprintf(error, sizeof(error), "no line and digit to lay a grid out with");
+    }
+    if (!ok) fprintf(stderr, "vega: %s: %s\n", path, error);
+    return ok; /* the bytes stay: the face reads them */
+}
+
 int main(int argc, char **argv) {
     unsigned width = 0, height = 0, port = 8080;
+    const char *symbols_path = NULL;
+    float size = 16;
     bool dumped = false, painting = false, watch = false, usage = argc < 3;
     const char *store = NULL, *listen_on = "127.0.0.1";
     for (int i = 3; !usage && i < argc; i += 2) {
@@ -571,24 +629,33 @@ int main(int argc, char **argv) {
         else if (!strcmp(argv[i], "--listen") && !strcmp(argv[1], "web")) listen_on = argv[i + 1];
         else if (!strcmp(argv[i], "--port") && !strcmp(argv[1], "web") && sscanf(argv[i + 1], "%u", &port) == 1 &&
                  port < 65536) {}
-        else if ((!strcmp(argv[i], "--dump") || !strcmp(argv[i], "--paint")) &&
+        else if ((!strcmp(argv[i], "--dump") || !strcmp(argv[i], "--paint") ||
+                  (!strcmp(argv[i], "--grid") && !strcmp(argv[1], "pixels"))) &&
                  sscanf(argv[i + 1], "%ux%u", &width, &height) == 2 && width && height && width <= 1000 && height <= 1000)
             dumped = true, painting = !strcmp(argv[i], "--paint");
+        else if (!strcmp(argv[i], "--symbols") && !strcmp(argv[1], "pixels")) symbols_path = argv[i + 1];
+        else if (!strcmp(argv[i], "--out") && !strcmp(argv[1], "pixels")) frames_prefix = argv[i + 1];
+        else if (!strcmp(argv[i], "--size") && !strcmp(argv[1], "pixels") && sscanf(argv[i + 1], "%f", &size) == 1) {}
         else usage = true;
     }
-    if (usage || (dumped && strcmp(argv[1], "tui")) || (!strcmp(argv[1], "check") && argc != 3)) {
+    bool pixels = argc > 1 && !strcmp(argv[1], "pixels");
+    if (usage || (dumped && strcmp(argv[1], "tui") && !pixels) || (!strcmp(argv[1], "check") && argc != 3) ||
+        (pixels && (!dumped || !symbols_path || !frames_prefix))) {
         fputs("vega tui|cli|say MODULE.pmod [--store PATH]\n"
               "vega tui MODULE.pmod [--store PATH] [--watch] | --dump|--paint WIDTHxHEIGHT < script\n"
               "vega web MODULE.pmod [--store PATH] [--listen ADDRESS] [--port N] [--watch]\n"
+              "vega pixels MODULE.pmod [--store PATH] --symbols FONT.vsym [--size PX] --grid WIDTHxHEIGHT --out PREFIX < script\n"
               "vega check MODULE.pmod\n", stderr);
         return 2;
     }
+    if (pixels && !open_face(symbols_path, size)) return 2;
     if (!strcmp(argv[1], "check")) {
         if (!load_module(argv[2], &modules[0])) return 2;
         return vega_check(&modules[0], print_finding, argv[2]) ? 1 : 0;
     }
     Surface surface = !strcmp(argv[1], "cli") ? SURFACE_CLI : !strcmp(argv[1], "say") ? SURFACE_SAY :
-                      !strcmp(argv[1], "tui") ? SURFACE_TUI : !strcmp(argv[1], "web") ? SURFACE_WEB : (Surface)-1;
+                      !strcmp(argv[1], "tui") ? SURFACE_TUI : !strcmp(argv[1], "web") ? SURFACE_WEB :
+                      pixels ? SURFACE_PIXELS : (Surface)-1;
     if ((int)surface < 0) { fprintf(stderr, "vega: unknown surface %s\n", argv[1]); return 2; }
     if (!load(argv[2], store)) return 2;
     if (watch && !dumped) {