vte: Add dim support

src/tsm/libtsm.h

@@ -170,6 +170,7 @@ struct tsm_screen_attr {
 	unsigned int inverse : 1;	/* inverse colors */
 	unsigned int protect : 1;	/* cannot be erased */
 	unsigned int blink : 1;		/* blinking character */
+	unsigned int dim:1;		/* dim color */
 };
 
 /* Attributes that alter the glyph shape */

src/tsm/tsm-render.c

@@ -193,6 +193,13 @@ tsm_age_t tsm_screen_draw(struct tsm_screen *con, tsm_screen_draw_cb draw_cb,
 	}
 }
 
+static void color_dim(struct tsm_screen_color  *out, const struct tsm_screen_color *fg, const struct tsm_screen_color *bg)
+{
+	out->r = bg->r / 2 + fg->r / 2;
+	out->g = bg->g / 2 + fg->g / 2;
+	out->b = bg->b / 2 + fg->b / 2;
+}
+
 /*
  * tsm_screen_draw2 returns a pointer to a table of tsm_screen_cell, one for each cell on the screen.
  * It uses a bit more memory, but should be much faster, as each cell is only 12 bytes.
@@ -287,6 +294,9 @@ const struct tsm_screen_cell *tsm_screen_draw2(struct tsm_screen *con)
 				out->bg.g = cell->attr.bg;
 				out->bg.b = cell->attr.bb;
 			}
+			if (cell->attr.dim)
+				color_dim(&out->fg, &out->fg, &out->bg);
+
 			if (sel_end && j == con->sel_end.x)
 				in_sel = !in_sel;
 		}

src/tsm/tsm-vte.c

@@ -791,6 +791,7 @@ static void reset_state(struct tsm_vte *vte)
 	vte->saved_state.cattr.inverse = 0;
 	vte->saved_state.cattr.protect = 0;
 	vte->saved_state.cattr.blink = 0;
+	vte->saved_state.cattr.dim = 0;
 }
 
 static void save_state(struct tsm_vte *vte)
@@ -1332,10 +1333,14 @@ static void csi_attribute(struct tsm_vte *vte)
 			vte->cattr.underline = 0;
 			vte->cattr.inverse = 0;
 			vte->cattr.blink = 0;
+			vte->cattr.dim = 0;
 			break;
 		case 1:
 			vte->cattr.bold = 1;
 			break;
+		case 2:
+			vte->cattr.dim = 1;
+			break;
 		case 3:
 			vte->cattr.italic = 1;
 			break;
@@ -1350,6 +1355,7 @@ static void csi_attribute(struct tsm_vte *vte)
 			break;
 		case 22:
 			vte->cattr.bold = 0;
+			vte->cattr.dim = 0;
 			break;
 		case 23:
 			vte->cattr.italic = 0;