Support kitty image protocol

etc.c

@@ -2016,6 +2016,10 @@ base64_encode(const unsigned char *src, size_t len)
     unsigned long j;
     size_t k;
 
+
+    if (!len)
+	return NULL;
+
     k = len;
     if (k % 3)
       k += 3 - (k % 3);

fm.h

@@ -316,6 +316,7 @@ extern int REV_LB[];
 #define INLINE_IMG_OSC5379	1
 #define INLINE_IMG_SIXEL	2
 #define INLINE_IMG_ITERM2	3
+#define INLINE_IMG_KITTY	4
 
 /* 
  * Types.

image.c

@@ -198,6 +198,8 @@ syncImage(void)
 void put_image_osc5379(char *url, int x, int y, int w, int h, int sx, int sy, int sw, int sh);
 void put_image_sixel(char *url, int x, int y, int w, int h, int sx, int sy, int sw, int sh, int n_terminal_image);
 void put_image_iterm2(char *url, int x, int y, int w, int h);
+void put_image_kitty(char *url, int x, int y, int w, int h, int sx, int sy, int
+    sw, int sh, int c, int r);
 
 void
 drawImage()
@@ -256,6 +258,8 @@ drawImage()
 		put_image_osc5379(url, x, y, w, h, sx, sy, sw, sh);
 	    } else if (enable_inline_image == INLINE_IMG_ITERM2) {
 		put_image_iterm2(url, x, y, sw, sh);
+	    } else if (enable_inline_image == INLINE_IMG_KITTY) {
+		put_image_kitty(url, x, y, w, h, i->sx, i->sy, sw * pixel_per_char, sh * pixel_per_line_i, sw, sh);
 	    }
 
 	    continue ;

rc.c

@@ -374,6 +374,7 @@ static struct sel_c inlineimgstr[] = {
     {N_S(INLINE_IMG_OSC5379), N_("OSC 5379 (mlterm)")},
     {N_S(INLINE_IMG_SIXEL), N_("sixel (img2sixel)")},
     {N_S(INLINE_IMG_ITERM2), N_("OSC 1337 (iTerm2)")},
+    {N_S(INLINE_IMG_KITTY), N_("kitty (PNG only)")},
     {0, NULL, NULL}
 };
 #endif				/* USE_IMAGE */

terms.c

@@ -521,7 +521,6 @@ put_image_iterm2(char *url, int x, int y, int w, int h)
     i = 0;
     while ((c = fgetc(fp)) != EOF) {
 	cbuf[i] = c;
-	Strcat_char(buf, c);
 	++i;
 	if (i == 3072) {
 	    base64 = base64_encode(cbuf, i);
@@ -547,6 +546,85 @@ put_image_iterm2(char *url, int x, int y, int w, int h)
     MOVE(Currentbuf->cursorY,Currentbuf->cursorX);
 }
 
+void
+put_image_kitty(char *url, int x, int y, int w, int h, int sx, int sy, int sw,
+    int sh, int cols, int rows)
+{
+    Str buf;
+    char *base64, *cbuf, *type;
+    FILE *fp;
+    int c, i, j, k, t;
+    struct stat st;
+
+    if (stat(url, &st))
+	return;
+
+    fp = fopen(url, "r");
+    if (!fp)
+	return;
+
+    type = guessContentType(url);
+    if(!strcasecmp(type, "image/png")) {
+      t = 100;
+    } else {
+      /* TODO: kitty +kitten icat or link imlib/gdkpixbuf? */
+      return;
+    }
+
+    MOVE(y, x);
+    buf = Sprintf("\x1b_Gf=100,s=%d,v=%d,a=T,m=1,X=%d,Y=%d,x=%d,y=%d,"
+	"w=%d,h=%d,c=%d,r=%d;",
+	w, h, x, y, sx, sy, sw, sh, cols, rows);
+
+    writestr(buf->ptr);
+
+    cbuf = GC_MALLOC_ATOMIC(3072);
+    i = 0;
+    j = buf->length;
+
+    while (buf->length + i / 3 * 4 < 4096 && (c = fgetc(fp)) != EOF) {
+	cbuf[i] = c;
+	++i;
+    }
+
+    base64 = base64_encode(cbuf, i);
+    if (!base64)
+	return;
+
+    buf = Sprintf("%s\x1b\\", base64);
+    writestr(buf->ptr);
+    i = 0;
+    base64 = NULL;
+
+    while ((c = fgetc(fp)) != EOF) {
+	if (!i && base64) {
+	    buf = Sprintf("\x1b_Gm=1;%s\x1b\\", base64);
+	    writestr(buf->ptr);
+	}
+	cbuf[i] = c;
+	++i;
+	if (i == 3072) {
+	    base64 = base64_encode(cbuf, i);
+	    if (!base64)
+		return;
+
+	    i = 0;
+	}
+    }
+
+    if (i) {
+	base64 = base64_encode(cbuf, i);
+	if (!base64)
+	    return;
+    }
+
+    if (base64) {
+	buf = Sprintf("\x1b_Gm=0;%s\x1b\\", base64);
+	writestr(buf->ptr);
+    }
+    MOVE(Currentbuf->cursorY, Currentbuf->cursorX);
+}
+
 static void
 save_gif(const char *path, u_char *header, size_t  header_size, u_char *body, size_t body_size)
 {