videotestsrc: Draw smpte test pattern + snow

spa/plugins/videotestsrc/videotestsrc.c

@@ -95,6 +95,126 @@ struct _SpaVideoTestSrc {
   SpaVideoTestSrcState state[1];
 };
 
+enum
+{
+  GRAY = 0,
+  YELLOW,
+  CYAN,
+  GREEN,
+  MAGENTA,
+  RED,
+  BLUE,
+  BLACK,
+  NEG_I,
+  WHITE,
+  POS_Q,
+  DARK_BLACK,
+  LIGHT_BLACK,
+  N_COLORS
+};
+
+struct pixel
+{
+  char R;
+  char G;
+  char B;
+};
+
+static struct pixel colors[N_COLORS] =
+{
+  {191, 191, 191}, /* GRAY */
+  {191, 191, 0},   /* YELLOW */
+  {0, 191, 191},   /* CYAN */
+  {0, 191, 0},     /* GREEN */
+  {191, 0, 191},   /* MAGENTA */
+  {191, 0, 0},     /* RED */
+  {0, 0, 191},     /* BLUE */
+  {19, 19, 19},    /* BLACK */
+  {0, 33, 76},     /* NEGATIVE I */
+  {255, 255, 255}, /* WHITE */
+  {49, 0, 107},    /* POSITIVE Q */
+  {9, 9, 9},       /* DARK BLACK */
+  {29, 29, 29},    /* LIGHT BLACK */
+};
+
+static void
+draw_line (char *data, struct pixel *c, int w)
+{
+  int i;
+
+  for (i = 0; i < w; i++) {
+    data[i * PIXEL_SIZE + 0] = c->R;
+    data[i * PIXEL_SIZE + 1] = c->G;
+    data[i * PIXEL_SIZE + 2] = c->B;
+  }
+}
+
+#define DRAW_LINE(data,line,offset,color,width) \
+  draw_line (data + (line * w + offset) * PIXEL_SIZE, colors + color, width);
+
+static void
+draw_smpte_snow (SpaVideoTestSrcState *state, char *data)
+{
+  int h, w;
+  int y1, y2;
+  int i, j;
+
+  w = STATE_GET_IMAGE_WIDTH (state);
+  h = STATE_GET_IMAGE_HEIGHT (state);
+  y1 = 2 * h / 3;
+  y2 = 3 * h / 4;
+
+  for (i = 0; i < y1; i++) {
+    for (j = 0; j < 7; j++) {
+      int x1 = j * w / 7;
+      int x2 = (j + 1) * w / 7;
+      DRAW_LINE (data, i, x1, j, x2 - x1);
+    }
+  }
+
+  for (i = y1; i < y2; i++) {
+    for (j = 0; j < 7; j++) {
+      int x1 = j * w / 7;
+      int x2 = (j + 1) * w / 7;
+      int c = (j & 1) ? BLACK : BLUE - j;
+
+      DRAW_LINE (data, i, x1, c, x2 - x1);
+    }
+  }
+
+  for (i = y2; i < h; i++) {
+    int x = 0;
+
+    /* negative I */
+    DRAW_LINE (data, i, x, NEG_I, w / 6);
+    x += w / 6;
+
+    /* white */
+    DRAW_LINE (data, i, x, WHITE, w / 6);
+    x += w / 6;
+
+    /* positive Q */
+    DRAW_LINE (data, i, x, POS_Q, w / 6);
+    x += w / 6;
+
+    /* pluge */
+    DRAW_LINE (data, i, x, DARK_BLACK, w / 12);
+    x += w / 12;
+    DRAW_LINE (data, i, x, BLACK, w / 12);
+    x += w / 12;
+    DRAW_LINE (data, i, x, LIGHT_BLACK, w / 12);
+    x += w / 12;
+
+    /* war of the ants (a.k.a. snow) */
+    for (j = x; j < w; j++) {
+      unsigned char r = rand ();
+      data[(i * w + j) * PIXEL_SIZE + 0] = r;
+      data[(i * w + j) * PIXEL_SIZE + 1] = r;
+      data[(i * w + j) * PIXEL_SIZE + 2] = r;
+    }
+  }
+}
+
 static int
 spa_videotestsrc_draw (SpaVideoTestSrcState *state, VTSBuffer *b)
 {
@@ -110,8 +230,7 @@ spa_videotestsrc_draw (SpaVideoTestSrcState *state, VTSBuffer *b)
     return -1;
   }
 
-  /* draw light gray */
-  memset (ptr, 0xDF, STATE_GET_IMAGE_SIZE (state));
+  draw_smpte_snow (state, ptr);
 
   spa_memory_unref (mem_ref);