Implementing Back Color Erase (BCE).

2 files changed, 40 insertions, 25 deletions

diff --git a/st.c b/st.c
index 769de8b..5f75c39 100644
--- a/st.c
+++ b/st.c
@@ -152,7 +152,7 @@ typedef struct {
         uchar state; /* state flags    */
 } Glyph;
 
-typedef Glyph* Line;
+typedef Glyph *Line;
 
 typedef struct {
         Glyph attr;      /* current char attributes */
@@ -303,7 +303,7 @@ static void strhandle(void);
 static void strparse(void);
 static void strreset(void);
 
-static void tclearregion(int, int, int, int);
+static void tclearregion(int, int, int, int, int);
 static void tcursor(int);
 static void tdeletechar(int);
 static void tdeleteline(int);
@@ -1113,7 +1113,7 @@ treset(void) {
         term.bot = term.row - 1;
         term.mode = MODE_WRAP;
 
-        tclearregion(0, 0, term.col-1, term.row-1);
+        tclearregion(0, 0, term.col-1, term.row-1, 0);
         tmoveto(0, 0);
         tcursor(CURSOR_SAVE);
 }
@@ -1157,7 +1157,7 @@ tscrolldown(int orig, int n) {
 
         LIMIT(n, 0, term.bot-orig+1);
 
-        tclearregion(0, term.bot-n+1, term.col-1, term.bot);
+        tclearregion(0, term.bot-n+1, term.col-1, term.bot, 0);
 
         for(i = term.bot; i >= orig+n; i--) {
                 temp = term.line[i];
@@ -1177,7 +1177,7 @@ tscrollup(int orig, int n) {
         Line temp;
         LIMIT(n, 0, term.bot-orig+1);
 
-        tclearregion(0, orig, term.col-1, orig+n-1);
+        tclearregion(0, orig, term.col-1, orig+n-1, 0);
 
         for(i = orig; i <= term.bot-n; i++) {
                  temp = term.line[i];
@@ -1305,7 +1305,7 @@ tsetchar(char *c, Glyph *attr, int x, int y) {
 }
 
 void
-tclearregion(int x1, int y1, int x2, int y2) {
+tclearregion(int x1, int y1, int x2, int y2, int bce) {
         int x, y, temp;
 
         if(x1 > x2)
@@ -1320,8 +1320,15 @@ tclearregion(int x1, int y1, int x2, int y2) {
 
         for(y = y1; y <= y2; y++) {
                 term.dirty[y] = 1;
-                for(x = x1; x <= x2; x++)
-                        term.line[y][x].state = 0;
+                for(x = x1; x <= x2; x++) {
+                        if(bce) {
+                                term.line[y][x] = term.c.attr;
+                                memcpy(term.line[y][x].c, " ", 2);
+                                term.line[y][x].state |= GLYPH_SET;
+                        } else {
+                                term.line[y][x].state = 0;
+                        }
+                }
         }
 }
 
@@ -1334,13 +1341,13 @@ tdeletechar(int n) {
         term.dirty[term.c.y] = 1;
 
         if(src >= term.col) {
-                tclearregion(term.c.x, term.c.y, term.col-1, term.c.y);
+                tclearregion(term.c.x, term.c.y, term.col-1, term.c.y, 0);
                 return;
         }
 
         memmove(&term.line[term.c.y][dst], &term.line[term.c.y][src],
                         size * sizeof(Glyph));
-        tclearregion(term.col-n, term.c.y, term.col-1, term.c.y);
+        tclearregion(term.col-n, term.c.y, term.col-1, term.c.y, 0);
 }
 
 void
@@ -1352,13 +1359,13 @@ tinsertblank(int n) {
         term.dirty[term.c.y] = 1;
 
         if(dst >= term.col) {
-                tclearregion(term.c.x, term.c.y, term.col-1, term.c.y);
+                tclearregion(term.c.x, term.c.y, term.col-1, term.c.y, 0);
                 return;
         }
 
         memmove(&term.line[term.c.y][dst], &term.line[term.c.y][src],
                         size * sizeof(Glyph));
-        tclearregion(src, term.c.y, dst - 1, term.c.y);
+        tclearregion(src, term.c.y, dst - 1, term.c.y, 0);
 }
 
 void
@@ -1542,8 +1549,10 @@ tsetmode(bool priv, bool set, int *args, int narg) {
                         case 47:
                         case 1047: {
                                 alt = IS_SET(MODE_ALTSCREEN);
-                                if(alt)
-                                        tclearregion(0, 0, term.col-1, term.row-1);
+                                if(alt) {
+                                        tclearregion(0, 0, term.col-1,
+                                                        term.row-1, 0);
+                                }
                                 if(set ^ alt)           /* set is always 1 or 0 */
                                         tswapscreen();
                                 if(*args != 1049)
@@ -1662,17 +1671,19 @@ csihandle(void) {
                 sel.bx = -1;
                 switch(csiescseq.arg[0]) {
                 case 0: /* below */
-                        tclearregion(term.c.x, term.c.y, term.col-1, term.c.y);
-                        if(term.c.y < term.row-1)
-                                tclearregion(0, term.c.y+1, term.col-1, term.row-1);
+                        tclearregion(term.c.x, term.c.y, term.col-1, term.c.y, 1);
+                        if(term.c.y < term.row-1) {
+                                tclearregion(0, term.c.y+1, term.col-1,
+                                                term.row-1, 1);
+                        }
                         break;
                 case 1: /* above */
                         if(term.c.y > 1)
-                                tclearregion(0, 0, term.col-1, term.c.y-1);
-                        tclearregion(0, term.c.y, term.c.x, term.c.y);
+                                tclearregion(0, 0, term.col-1, term.c.y-1, 1);
+                        tclearregion(0, term.c.y, term.c.x, term.c.y, 1);
                         break;
                 case 2: /* all */
-                        tclearregion(0, 0, term.col-1, term.row-1);
+                        tclearregion(0, 0, term.col-1, term.row-1, 1);
                         break;
                 default:
                         goto unknown;
@@ -1681,13 +1692,14 @@ csihandle(void) {
         case 'K': /* EL -- Clear line */
                 switch(csiescseq.arg[0]) {
                 case 0: /* right */
-                        tclearregion(term.c.x, term.c.y, term.col-1, term.c.y);
+                        tclearregion(term.c.x, term.c.y, term.col-1,
+                                        term.c.y, 1);
                         break;
                 case 1: /* left */
-                        tclearregion(0, term.c.y, term.c.x, term.c.y);
+                        tclearregion(0, term.c.y, term.c.x, term.c.y, 1);
                         break;
                 case 2: /* all */
-                        tclearregion(0, term.c.y, term.col-1, term.c.y);
+                        tclearregion(0, term.c.y, term.col-1, term.c.y, 1);
                         break;
                 }
                 break;
@@ -1712,7 +1724,8 @@ csihandle(void) {
                 break;
         case 'X': /* ECH -- Erase <n> char */
                 DEFAULT(csiescseq.arg[0], 1);
-                tclearregion(term.c.x, term.c.y, term.c.x + csiescseq.arg[0], term.c.y);
+                tclearregion(term.c.x, term.c.y, term.c.x + csiescseq.arg[0],
+                                term.c.y, 0);
                 break;
         case 'P': /* DCH -- Delete <n> char */
                 DEFAULT(csiescseq.arg[0], 1);
@@ -2505,6 +2518,7 @@ xinit(void) {
                 xw.fy = 0;
         }
 
+        /* Events */
         attrs.background_pixel = dc.col[defaultbg].pixel;
         attrs.border_pixel = dc.col[defaultbg].pixel;
         attrs.bit_gravity = NorthWestGravity;
@@ -2898,6 +2912,7 @@ drawregion(int x1, int y1, int x2, int y2) {
                                         ox = x;
                                         base = new;
                                 }
+
                                 sl = utf8size(new.c);
                                 memcpy(buf+ib, new.c, sl);
                                 ib += sl;
diff --git a/st.info b/st.info
index fcaa024..1c83dc1 100644
--- a/st.info
+++ b/st.info
@@ -3,7 +3,7 @@
 st| simpleterm,
         acsc=``aaffggiijjkkllmmnnooppqqrrssttuuvvwwxxyyzz{{||}}~~,
         am,
-#       bce,
+        bce,
         bel=^G,
 #       blink=\E[5m,
         bold=\E[1m,