From 79826cdbba8fe52e05ccf69e7722890e85cc0d1a Mon Sep 17 00:00:00 2001
From: Keith Packard <keithp@keithp.com>
Date: Mon, 27 Feb 2023 14:39:03 -0800
Subject: [PATCH] altos/draw: Use damage for lco demo

Do some incremental drawing to demonstrate damage in action

Signed-off-by: Keith Packard <keithp@keithp.com>
---
 src/draw/lco-test.c   | 20 +++++++++++++++++---
 src/draw/test-frame.c | 10 ++++++----
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/src/draw/lco-test.c b/src/draw/lco-test.c
index bb45e187..74671de5 100644
--- a/src/draw/lco-test.c
+++ b/src/draw/lco-test.c
@@ -135,14 +135,18 @@ prev_box(void)
 	box_number = max_box;
 }
 
+static bool redraw_all = true;
+
 void HandleExpose(Display *dpy, Window win, GC gc)
 {
 	char	str[64];
 	int 	i;
 	int	v;
+	int	last_box;
 	int16_t	b;
 
-	ao_rect(&fb, 0, 0, WIDTH, HEIGHT, 0xffffffff, AO_COPY);
+	if (redraw_all)
+		ao_rect(&fb, 0, 0, WIDTH, HEIGHT, 0xffffffff, AO_COPY);
 
 	if (do_polys == 1)
 		current_timeout = TIMEOUT;
@@ -150,13 +154,19 @@ void HandleExpose(Display *dpy, Window win, GC gc)
 		current_timeout = 0;
 	switch (do_polys) {
 	case 1:
-		ao_logo(&fb, &logo_transform, &LOGO_FONT, 0x00000000, AO_COPY);
+		if (redraw_all)
+			ao_logo(&fb, &logo_transform, &LOGO_FONT, 0x00000000, AO_COPY);
+		else
+			ao_rect(&fb, 0, SCAN_Y, WIDTH, HEIGHT-SCAN_Y, 0xffffffff, AO_COPY);
 		if (scan_number) {
 			ao_rect(&fb, SCAN_X, SCAN_Y, (int16_t) scan_number, SCAN_HEIGHT, 0x00000000, AO_COPY);
 			b = 0;
 			v = 0;
+			last_box = 0;
 			for (i = scan_number; i > 1; i--) {
 				if (valid_box(i)) {
+					if (!last_box)
+						last_box = i;
 					v++;
 					if (v == MAX_VALID)
 						break;
@@ -164,11 +174,12 @@ void HandleExpose(Display *dpy, Window win, GC gc)
 			}
 			for (; i <= scan_number; i++) {
 				if (valid_box(i)) {
-					sprintf(str, "%02d", i);
+					sprintf(str, "%02d%s", i, i == last_box ? "" : ",");
 					ao_text(&fb, &TINY_FONT, 0 + FOUND_WIDTH * b, FOUND_Y, str, 0x00000000, AO_COPY);
 					b++;
 				}
 			}
+			redraw_all = false;
 		}
 		break;
 	case 2:
@@ -221,6 +232,8 @@ void
 HandleKeyPress(Display *dpy, Window win, GC gc, XEvent *ev)
 {
 	char	string[10];
+
+	redraw_all = true;
 	if (XLookupString ((XKeyEvent *) ev, string, sizeof (string), 0, 0) >= 1) {
 		switch (string[0]) {
 		case 'q':
@@ -290,6 +303,7 @@ HandleTimeout(Display *dpy, Window win, GC gc)
 		if (scan_number < 99)
 			scan_number++;
 		else {
+			redraw_all = true;
 			box_number = boxes[0];
 			pad_number = 1;
 			do_polys = 0;
diff --git a/src/draw/test-frame.c b/src/draw/test-frame.c
index a90dfc74..fc054738 100644
--- a/src/draw/test-frame.c
+++ b/src/draw/test-frame.c
@@ -44,7 +44,8 @@ static struct ao_bitmap fb = {
 	.base = bits,
 	.stride = STRIDE,
 	.width = WIDTH,
-	.height = HEIGHT
+	.height = HEIGHT,
+	.damage = AO_BOX_INIT,
 };
 
 static XImage *shm_image;
@@ -83,11 +84,11 @@ DoDisplay(Display *dpy, Window win, GC gc)
 	else
 		image = nonshm_image;
 
-	scan = bits;
-	for (iy = 0; iy < HEIGHT; iy++) {
+	scan = bits + STRIDE * fb.damage.y1;
+	for (iy = fb.damage.y1; iy < fb.damage.y2; iy++) {
 		w = scan;
 		scan += STRIDE;
-		for (ix = 0; ix < WIDTH; ix += 32) {
+		for (ix = fb.damage.x1 & ~31; ix < fb.damage.x2; ix += 32) {
 			d = *w++;
 			for (ib = 0; ib < 32 && ix + ib < WIDTH; ib++) {
 				unsigned long p = d & 1 ? white : black;
@@ -105,4 +106,5 @@ DoDisplay(Display *dpy, Window win, GC gc)
 		XShmPutImage(dpy, win, gc, image, 0, 0, 0, 0, IMAGE_WIDTH, IMAGE_HEIGHT, False);
 	else
 		XPutImage(dpy, win, gc, image, 0, 0, 0, 0, IMAGE_WIDTH, IMAGE_HEIGHT);
+	ao_damage_set_empty(&fb);
 }
-- 
2.30.2