Track sprite positions in the Cell structure

kitty/data-types.h

@@ -59,6 +59,7 @@ typedef uint16_t sprite_index;
 #define UTF8_REJECT 1
 #define UNDERCURL_CODE 6
 #define DECORATION_FG_CODE 58
+#define CHAR_IS_BLANK(ch) ((ch & CHAR_MASK) == 32 || (ch & CHAR_MASK) == 0)
 
 #define CURSOR_BLOCK 1
 #define CURSOR_BEAM 2
@@ -130,6 +131,7 @@ typedef struct {
     char_type ch;
     color_type fg, bg, decoration_fg;
     combining_type cc;
+    sprite_index sprite_x, sprite_y, sprite_z;
 } Cell;
 
 typedef struct {
@@ -288,11 +290,16 @@ typedef struct {
 } ChildMonitor;
 PyTypeObject ChildMonitor_Type;
 
+#define clear_sprite_position(cell) (cell).sprite_x = 0; (cell).sprite_y = 0; (cell).sprite_z = 0; 
+
 #define left_shift_line(line, at, num) \
     for(index_type __i__ = (at); __i__ < (line)->xnum - (num); __i__++) { \
         COPY_CELL(line, __i__ + (num), line, __i__) \
     } \
-    if ((((line)->cells[(at)].ch >> ATTRS_SHIFT) & WIDTH_MASK) != 1) (line)->cells[(at)].ch = (1 << ATTRS_SHIFT) | BLANK_CHAR;
+    if ((((line)->cells[(at)].ch >> ATTRS_SHIFT) & WIDTH_MASK) != 1) { \
+        (line)->cells[(at)].ch = (1 << ATTRS_SHIFT) | BLANK_CHAR; \
+        clear_sprite_position((line)->cells[(at)]); \
+    }
 
 
 // Global functions 
@@ -324,6 +331,7 @@ Cursor* cursor_copy(Cursor*);
 void cursor_copy_to(Cursor *src, Cursor *dest);
 void cursor_reset_display_attrs(Cursor*);
 bool update_cell_range_data(ScreenModes *modes, Line *, unsigned int, unsigned int, unsigned int *);
+void set_sprite_position(Cell *cell, Cell *previous_cell);
 
 PyObject* line_text_at(char_type, combining_type);
 void line_clear_text(Line *self, unsigned int at, unsigned int num, int ch);

kitty/line.c

@@ -219,11 +219,14 @@ width(Line *self, PyObject *val) {
     return PyLong_FromUnsignedLong((unsigned long) (attrs & WIDTH_MASK));
 }
 
+#define set_sprite_position_at(x) set_sprite_position(self->cells + x, x == 0 ? NULL : self->cells + x - 1);
+
 void 
 line_add_combining_char(Line *self, uint32_t ch, unsigned int x) {
     combining_type c = self->cells[x].cc;
     if (c & CC_MASK) self->cells[x].cc = (c & CC_MASK) | ( (ch & CC_MASK) << CC_SHIFT );
     else self->cells[x].cc = ch & CC_MASK;
+    set_sprite_position_at(x);
 }
 
 static PyObject*
@@ -273,6 +276,7 @@ set_text(Line* self, PyObject *args) {
         self->cells[i].bg = bg;
         self->cells[i].decoration_fg = dfg;
         self->cells[i].cc = 0;
+        set_sprite_position_at(i);
     }
 
     Py_RETURN_NONE;
@@ -302,9 +306,16 @@ cursor_from(Line* self, PyObject *args) {
 void 
 line_clear_text(Line *self, unsigned int at, unsigned int num, int ch) {
     const char_type repl = ((char_type)ch & CHAR_MASK) | (1 << ATTRS_SHIFT);
-    for (index_type i = at; i < MIN(self->xnum, at + num); i++) {
+#define PREFIX \
-        self->cells[i].ch = (self->cells[i].ch  & ATTRS_MASK_WITHOUT_WIDTH) | repl;
+    for (index_type i = at; i < MIN(self->xnum, at + num); i++) { \
+        self->cells[i].ch = (self->cells[i].ch  & ATTRS_MASK_WITHOUT_WIDTH) | repl; \
         self->cells[i].cc = 0; 
+    if (CHAR_IS_BLANK(ch)) {
+        PREFIX
+        clear_sprite_position(self->cells[i]); }
+    } else {
+        PREFIX
+        set_sprite_position_at(i)}
     }
 }
 
@@ -329,9 +340,11 @@ line_apply_cursor(Line *self, Cursor *cursor, unsigned int at, unsigned int num,
         if (clear_char) {
             self->cells[i].ch = BLANK_CHAR | attrs;
             self->cells[i].cc = 0;
+            clear_sprite_position(self->cells[i]);
         } else {
             char_type w = ((self->cells[i].ch >> ATTRS_SHIFT) & WIDTH_MASK) << ATTRS_SHIFT;
             self->cells[i].ch = (self->cells[i].ch & CHAR_MASK) | attrs | w;
+            set_sprite_position_at(i);
         }
         self->cells[i].fg = fg; self->cells[i].bg = bg;
         self->cells[i].decoration_fg = dfg;
@@ -355,7 +368,10 @@ void line_right_shift(Line *self, unsigned int at, unsigned int num) {
     }
     // Check if a wide character was split at the right edge
     char_type w = (self->cells[self->xnum - 1].ch >> ATTRS_SHIFT) & WIDTH_MASK;
-    if (w != 1) self->cells[self->xnum - 1].ch = (1 << ATTRS_SHIFT) | BLANK_CHAR;
+    if (w != 1) {
+        self->cells[self->xnum - 1].ch = (1 << ATTRS_SHIFT) | BLANK_CHAR;
+        clear_sprite_position(self->cells[self->xnum - 1]);
+    }
 }
 
 static PyObject*
@@ -399,6 +415,8 @@ line_set_char(Line *self, unsigned int at, uint32_t ch, unsigned int width, Curs
     }
     self->cells[at].ch = (ch & CHAR_MASK) | attrs;
     self->cells[at].cc = 0;
+    if (CHAR_IS_BLANK(ch)) { clear_sprite_position(self->cells[at]); }
+    else set_sprite_position_at(at);
 }
 
 static PyObject*

kitty/lineops.h

@@ -8,12 +8,23 @@
 
 #include "data-types.h"
 
+static inline void
+update_sprites_in_line(Cell *cells, index_type xnum) {
+    if (LIKELY(xnum > 0)) {
+        set_sprite_position(cells, NULL);
+        for (index_type i = 1; i < xnum; i++) {
+            set_sprite_position(cells + i, cells + i - 1);
+        }
+    }
+}
+
 static inline void
 set_attribute_on_line(Cell *cells, uint32_t shift, uint32_t val, index_type xnum) {
     uint32_t mask = shift == DECORATION_SHIFT ? 3 : 1;
     uint32_t aval = (val & mask) << (ATTRS_SHIFT + shift); 
     mask = ~(mask << (ATTRS_SHIFT + shift));
     for (index_type i = 0; i < xnum; i++) cells[i].ch = (cells[i].ch & mask) | aval;
+    if (shift == BOLD_SHIFT || shift == ITALIC_SHIFT) update_sprites_in_line(cells, xnum);
 }
 
 static inline void
@@ -28,6 +39,7 @@ copy_line(const Line *src, Line *dest) {
 
 static inline void
 clear_chars_in_line(Cell *cells, index_type xnum, char_type ch) {
+    // Clear only the char part of each cell, the rest must have been cleared by a memset or similar
     char_type c = (1 << ATTRS_SHIFT) | ch;
     for (index_type i = 0; i < xnum; i++) cells[i].ch = c;
 }

kitty/sprites.c

@@ -99,6 +99,21 @@ sprite_map_position_for(char_type ch, combining_type cc, bool is_second, int *er
     return s;
 }
 
+
+void
+set_sprite_position(Cell *cell, Cell *previous_cell) {
+    SpritePosition *sp;
+    static int error;
+    if (UNLIKELY(previous_cell != NULL && ((previous_cell->ch >> ATTRS_SHIFT) & WIDTH_MASK) == 2)) {
+        sp = sprite_map_position_for(previous_cell->ch, 0, true, &error);
+    } else {
+        sp = sprite_map_position_for(cell->ch, cell->cc, false, &error);
+    }
+    cell->sprite_x = sp->x;
+    cell->sprite_y = sp->y;
+    cell->sprite_z = sp->z;
+}
+
 PyObject*
 sprite_map_increment() {
 #define increment_doc "Increment the current position and return the old (x, y, z) values"