Add support for URxvt extension to include alpha in OSC-11 #437

Manually merged
dnkl merged 7 commits from osc-11-alpha into master 10 months ago
  1. 7
      CHANGELOG.md
  2. 4
      doc/foot-ctlseqs.7.scd
  3. 124
      osc.c
  4. 1
      terminal.c

7
CHANGELOG.md

@ -27,6 +27,11 @@
## Unreleased
### Added
* URxvt OSC-11 extension to set background alpha
(https://codeberg.org/dnkl/foot/issues/436).
### Changed
### Deprecated
### Removed
@ -39,7 +44,7 @@
(https://codeberg.org/dnkl/foot/issues/427).
* Wrong action referenced in error message for key binding collisions
(https://codeberg.org/dnkl/foot/issues/432).
* OSC-4/104 out-of-bounds accesses to the color table. This was the
* OSC 4/104 out-of-bounds accesses to the color table. This was the
reason pywal turned foot windows transparent
(https://codeberg.org/dnkl/foot/issues/434).
* PTY not being drained when the client application terminates.

4
doc/foot-ctlseqs.7.scd

@ -583,7 +583,9 @@ All _OSC_ sequences begin with *\\E]*, sometimes abbreviated _OSC_.
| \\E] 11 ; _spec_ \\E\\
: xterm
: Change the default background color to _spec_, a color in
*XParseColor* format.
XParseColor format. Foot implements URxvt's transparency extension;
e.g. _spec_=*[75]#ff00ff* or _spec_=*rgba:ff/00/ff/bf* (pink with
75% alpha).
| \\E] 12 ; _spec_ \\E\\
: xterm
: Change cursor color to _spec_, a color in *XParseColor* format.

124
osc.c

@ -261,8 +261,29 @@ osc_flash(struct terminal *term)
}
static bool
parse_legacy_color(const char *string, uint32_t *color)
parse_legacy_color(const char *string, uint32_t *color, bool *_have_alpha,
uint16_t *_alpha)
{
bool have_alpha = false;
uint16_t alpha = 0xffff;
if (string[0] == '[') {
/* e.g. \E]11;[50]#00ff00 */
const char *start = &string[1];
errno = 0;
char *end;
unsigned long percent = strtoul(start, &end, 10);
if (errno != 0 || *end != ']')
return false;
have_alpha = true;
alpha = (0xffff * min(percent, 100) + 50) / 100;
string = end + 1;
}
if (string[0] != '#')
return false;
@ -299,31 +320,53 @@ parse_legacy_color(const char *string, uint32_t *color)
uint8_t g = 256 * (rgb[1] / 65536.);
uint8_t b = 256 * (rgb[2] / 65536.);
LOG_DBG("legacy: %02x%02x%02x", r, g, b);
LOG_DBG("legacy: %02x%02x%02x (alpha=%04x)", r, g, b,
have_alpha ? alpha : 0xffff);
*color = r << 16 | g << 8 | b;
if (_have_alpha != NULL)
*_have_alpha = have_alpha;
if (_alpha != NULL)
*_alpha = alpha;
return true;
}
static bool
parse_rgb(const char *string, uint32_t *color)
parse_rgb(const char *string, uint32_t *color, bool *_have_alpha,
uint16_t *_alpha)
{
size_t len = strlen(string);
bool have_alpha = len >= 4 && strncmp(string, "rgba", 4) == 0;
/* Verify we have the minimum required length (for "rgb:x/x/x") */
if (len < 3 /* 'rgb' */ + 1 /* ':' */ + 2 /* '/' */ + 3 * 1 /* 3 * 'x' */)
return false;
/* Verify prefix is "rgb:" */
if (string[0] != 'r' || string[1] != 'g' || string[2] != 'b' || string[3] != ':')
return false;
/* Verify we have the minimum required length (for "") */
if (have_alpha) {
/* rgba:x/x/x/x */
if (len < 4 /* 'rgba' */ + 1 /* ':' */ + 3 /* '/' */ + 4 * 1 /* 4 * 'x' */)
return false;
} else {
/* rgb:x/x/x */
if (len < 3 /* 'rgb' */ + 1 /* ':' */ + 2 /* '/' */ + 3 * 1 /* 3 * 'x' */)
return false;
}
string += 4;
len -= 4;
/* Verify prefix is “rgb:” or “rgba:” */
if (have_alpha) {
if (strncmp(string, "rgba:", 5) != 0)
return false;
string += 5;
len -= 5;
} else {
if (strncmp(string, "rgb:", 4) != 0)
return false;
string += 4;
len -= 4;
}
int rgb[3];
int digits[3];
int rgb[4];
int digits[4];
for (size_t i = 0; i < 3; i++) {
for (size_t i = 0; i < (have_alpha ? 4 : 3); i++) {
for (rgb[i] = 0, digits[i] = 0;
len > 0 && *string != '/';
len--, string++, digits[i]++)
@ -338,7 +381,7 @@ parse_rgb(const char *string, uint32_t *color)
c >= 'a' && c <= 'f' ? c - 'a' + 10 : c - 'A' + 10;
}
if (i >= 2)
if (i >= (have_alpha ? 3 : 2))
break;
if (len == 0 || *string != '/')
@ -351,7 +394,20 @@ parse_rgb(const char *string, uint32_t *color)
uint8_t g = 256 * (rgb[1] / (double)(1 << (4 * digits[1])));
uint8_t b = 256 * (rgb[2] / (double)(1 << (4 * digits[2])));
LOG_DBG("rgb: %02x%02x%02x", r, g, b);
uint16_t alpha = 0xffff;
if (have_alpha)
alpha = 65536 * (rgb[3] / (double)(1 << (4 * digits[3])));
if (have_alpha)
LOG_DBG("rgba: %02x%02x%02x (alpha=%04x)", r, g, b, alpha);
else
LOG_DBG("rgb: %02x%02x%02x", r, g, b);
if (_have_alpha != NULL)
*_have_alpha = have_alpha;
if (_alpha != NULL)
*_alpha = alpha;
*color = r << 16 | g << 8 | b;
return true;
}
@ -595,9 +651,9 @@ osc_dispatch(struct terminal *term)
else {
uint32_t color;
bool color_is_valid = s_color[0] == '#'
? parse_legacy_color(s_color, &color)
: parse_rgb(s_color, &color);
bool color_is_valid = s_color[0] == '#' || s_color[0] == '['
? parse_legacy_color(s_color, &color, NULL, NULL)
: parse_rgb(s_color, &color, NULL, NULL);
if (!color_is_valid)
continue;
@ -647,15 +703,29 @@ osc_dispatch(struct terminal *term)
}
uint32_t color;
if (string[0] == '#' ? !parse_legacy_color(string, &color) : !parse_rgb(string, &color))
bool have_alpha = false;
uint16_t alpha = 0xffff;
if (string[0] == '#' || string[0] == '['
? !parse_legacy_color(string, &color, &have_alpha, &alpha)
: !parse_rgb(string, &color, &have_alpha, &alpha))
{
break;
}
LOG_DBG("change color definition for %s to %06x",
param == 10 ? "foreground" : "background", color);
switch (param) {
case 10: term->colors.fg = color; break;
case 11: term->colors.bg = color; break;
case 10:
term->colors.fg = color;
break;
case 11:
term->colors.bg = color;
if (have_alpha)
term->colors.alpha = alpha;
break;
}
term_damage_view(term);
@ -678,8 +748,13 @@ osc_dispatch(struct terminal *term)
}
uint32_t color;
if (string[0] == '#' ? !parse_legacy_color(string, &color) : !parse_rgb(string, &color))
if (string[0] == '#' || string[0] == '['
? !parse_legacy_color(string, &color, NULL, NULL)
: !parse_rgb(string, &color, NULL, NULL))
{
break;
}
LOG_DBG("change cursor color to %06x", color);
@ -749,6 +824,7 @@ osc_dispatch(struct terminal *term)
case 111: /* Reset default text background color */
LOG_DBG("resetting background color");
term->colors.bg = term->conf->colors.bg;
term->colors.alpha = term->conf->colors.alpha;
term_damage_view(term);
term_damage_margins(term);
break;

1
terminal.c

@ -1682,6 +1682,7 @@ term_reset(struct terminal *term, bool hard)
fdm_del(term->fdm, term->blink.fd); term->blink.fd = -1;
term->colors.fg = term->conf->colors.fg;
term->colors.bg = term->conf->colors.bg;
term->colors.alpha = term->conf->colors.alpha;
memcpy(term->colors.table, term->conf->colors.table,
sizeof(term->colors.table));
term->origin = ORIGIN_ABSOLUTE;

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