[READ-ONLY] Mirror of https://github.com/bombshell-dev/tty. Platform independent 2D layout engine for terminal applications based on Clay
🐛 allow cell fill for different initialization types
This forces a render of all cells on the very first frame, which is
perfectly acceptable.
Charles Lowell
(Apr 10, 2026, 4:06 PM -0500)
0f964786
17c12cd4
+27
-12
+5
-4
src/cell.c
+5
-4
src/cell.c
···
2
2
3
3
#include "cell.h"
4
4
5
-
void cells_clear(Cell *buf, int w, int h) {
5
+
void cells_fill(Cell *buf, int w, int h, uint32_t ch, uint32_t fg,
6
+
uint32_t bg) {
6
7
for (int i = 0; i < w * h; i++) {
7
-
buf[i].ch = ' ';
8
-
buf[i].fg = ATTR_DEFAULT;
9
-
buf[i].bg = ATTR_DEFAULT;
8
+
buf[i].ch = ch;
9
+
buf[i].fg = fg;
10
+
buf[i].bg = bg;
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11
}
11
12
}
12
13
+1
-1
src/cell.h
+1
-1
src/cell.h
+21
-7
src/clayterm.c
+21
-7
src/clayterm.c
···
149
149
buf_char(&ct->out, ch);
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150
}
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151
152
-
/* ── Double-buffer diff (from termbox2 tb_present) ────────────────── */
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-
154
-
static void present(struct Clayterm *ct) {
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+
/**
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+
* Diff back buffer against front buffer and emit only changed cells
154
+
* using absolute CUP positioning (\x1b[row;colH). Unchanged cells are
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+
* skipped, making this efficient for subsequent frames where most of
156
+
* the screen is static. Derived from termbox2 tb_present.
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+
*/
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+
static void present_cups(struct Clayterm *ct) {
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159
ct->lastx = -1;
156
160
ct->lasty = -1;
157
161
···
191
195
}
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196
}
193
197
198
+
/**
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+
* Emit back buffer as newline-separated rows without CUP positioning.
200
+
* Every cell is written (no diffing), and the front buffer is primed
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+
* so that a subsequent present() call can diff efficiently. This is
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+
* used for inline "region" rendering where the caller manages cursor
203
+
* positioning externally and the output must work in pipes.
204
+
*/
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205
static void present_lines(struct Clayterm *ct) {
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206
for (int y = 0; y < ct->h; y++) {
196
207
if (y > 0)
···
416
427
.lasty = -1,
417
428
};
418
429
419
-
cells_clear(ct->front, w, h);
420
-
cells_clear(ct->back, w, h);
430
+
// initialize back buffer with spaces and default fg/bg
431
+
cells_fill(ct->back, w, h, ' ', ATTR_DEFAULT, ATTR_DEFAULT);
432
+
433
+
// initialize front buffer with zeros. Every cell will be
434
+
cells_fill(ct->front, w, h, 0, 0, 0);
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435
return ct;
422
436
}
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437
···
551
565
ct->lastfg = ct->lastbg = 0xffffffff;
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566
ct->lastx = ct->lasty = -1;
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567
554
-
cells_clear(ct->back, ct->w, ct->h);
568
+
cells_fill(ct->back, ct->w, ct->h, ' ', ATTR_DEFAULT, ATTR_DEFAULT);
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569
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570
/* walk Clay render commands into back buffer */
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571
for (int32_t j = 0; j < cmds.length; j++) {
···
590
604
if (mode == 1) {
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605
present_lines(ct);
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606
} else {
593
-
present(ct);
607
+
present_cups(ct);
594
608
}
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609
}
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610