[vte] sixel: Use special coulor registers for default foreground and background
- From: Christian Persch <chpe src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [vte] sixel: Use special coulor registers for default foreground and background
- Date: Thu, 12 Nov 2020 20:37:26 +0000 (UTC)
commit 65234343b88b12072ff8414ce9a6742ddbade407
Author: Hans Petter Jansson <hpj hpjansson org>
Date: Thu Nov 12 21:37:16 2020 +0100
sixel: Use special coulor registers for default foreground and background
... and implement background colour transparency using the second
parameter to DECSIXEL.
https://gitlab.gnome.org/GNOME/vte/-/issues/253
src/sixel-context.cc | 58 +++++++++++++++++++++++++++-------------------------
src/sixel-context.hh | 13 ++++++------
src/sixel-test.cc | 24 ++++++++++++++--------
src/vte.cc | 13 ++++++++++++
src/vteinternal.hh | 6 ++++++
src/vteseq.cc | 28 ++++++++++++++++++-------
6 files changed, 93 insertions(+), 49 deletions(-)
---
diff --git a/src/sixel-context.cc b/src/sixel-context.cc
index 7bfaeebe..d196ce6d 100644
--- a/src/sixel-context.cc
+++ b/src/sixel-context.cc
@@ -245,22 +245,22 @@ Context::reset_colors() noexcept
* Colours 9..14 (name marked with '*') are less saturated
* versions of colours 1..6.
*/
- m_colors[0 + 1] = make_color_rgb( 0, 0, 0); /* HLS( 0, 0, 0) */ /* Black */
- m_colors[1 + 1] = make_color_rgb(20, 20, 80); /* HLS( 0, 50, 60) */ /* Blue */
- m_colors[2 + 1] = make_color_rgb(80, 13, 13); /* HLS(120, 46, 72) */ /* Red */
- m_colors[3 + 1] = make_color_rgb(20, 80, 20); /* HLS(240, 50, 60) */ /* Green */
- m_colors[4 + 1] = make_color_rgb(80, 20, 80); /* HLS( 60, 50, 60) */ /* Magenta */
- m_colors[5 + 1] = make_color_rgb(20, 80, 80); /* HLS(300, 50, 60) */ /* Cyan */
- m_colors[6 + 1] = make_color_rgb(80, 80, 20); /* HLS(180, 50, 60) */ /* Yellow */
- m_colors[7 + 1] = make_color_rgb(53, 53, 53); /* HLS( 0, 53, 0) */ /* Grey 50% */
- m_colors[8 + 1] = make_color_rgb(26, 26, 26); /* HLS( 0, 26, 0) */ /* Grey 25% */
- m_colors[9 + 1] = make_color_rgb(33, 33, 60); /* HLS( 0, 46, 29) */ /* Blue* */
- m_colors[10 + 1] = make_color_rgb(60, 26, 26); /* HLS(120, 43, 39) */ /* Red* */
- m_colors[11 + 1] = make_color_rgb(33, 60, 33); /* HLS(240, 46, 29) */ /* Green* */
- m_colors[12 + 1] = make_color_rgb(60, 33, 60); /* HLS( 60, 46, 29) */ /* Magenta* */
- m_colors[13 + 1] = make_color_rgb(33, 60, 60); /* HLS(300, 46, 29) */ /* Cyan* */
- m_colors[14 + 1] = make_color_rgb(60, 60, 33); /* HLS(180, 46, 29) */ /* Yellow* */
- m_colors[15 + 1] = make_color_rgb(80, 80, 80); /* HLS( 0, 80, 0) */ /* Grey 75% */
+ m_colors[0 + 2] = make_color_rgb( 0, 0, 0); /* HLS( 0, 0, 0) */ /* Black */
+ m_colors[1 + 2] = make_color_rgb(20, 20, 80); /* HLS( 0, 50, 60) */ /* Blue */
+ m_colors[2 + 2] = make_color_rgb(80, 13, 13); /* HLS(120, 46, 72) */ /* Red */
+ m_colors[3 + 2] = make_color_rgb(20, 80, 20); /* HLS(240, 50, 60) */ /* Green */
+ m_colors[4 + 2] = make_color_rgb(80, 20, 80); /* HLS( 60, 50, 60) */ /* Magenta */
+ m_colors[5 + 2] = make_color_rgb(20, 80, 80); /* HLS(300, 50, 60) */ /* Cyan */
+ m_colors[6 + 2] = make_color_rgb(80, 80, 20); /* HLS(180, 50, 60) */ /* Yellow */
+ m_colors[7 + 2] = make_color_rgb(53, 53, 53); /* HLS( 0, 53, 0) */ /* Grey 50% */
+ m_colors[8 + 2] = make_color_rgb(26, 26, 26); /* HLS( 0, 26, 0) */ /* Grey 25% */
+ m_colors[9 + 2] = make_color_rgb(33, 33, 60); /* HLS( 0, 46, 29) */ /* Blue* */
+ m_colors[10 + 2] = make_color_rgb(60, 26, 26); /* HLS(120, 43, 39) */ /* Red* */
+ m_colors[11 + 2] = make_color_rgb(33, 60, 33); /* HLS(240, 46, 29) */ /* Green* */
+ m_colors[12 + 2] = make_color_rgb(60, 33, 60); /* HLS( 60, 46, 29) */ /* Magenta* */
+ m_colors[13 + 2] = make_color_rgb(33, 60, 60); /* HLS(300, 46, 29) */ /* Cyan* */
+ m_colors[14 + 2] = make_color_rgb(60, 60, 33); /* HLS(180, 46, 29) */ /* Yellow* */
+ m_colors[15 + 2] = make_color_rgb(80, 80, 80); /* HLS( 0, 80, 0) */ /* Grey 75% */
/* Devices may use the same colour palette for DECSIXEL as for
* text mode, so initialise colours 16..255 to the standard 256-colour
@@ -285,14 +285,14 @@ Context::reset_colors() noexcept
};
for (auto n = 0; n < 216; ++n)
- m_colors[n + 16 + 1] = make_cube_color(n / 36, (n / 6) % 6, n % 6);
+ m_colors[n + 16 + 2] = make_cube_color(n / 36, (n / 6) % 6, n % 6);
/* 24-colour greyscale ramp */
for (auto n = 0; n < 24; ++n)
- m_colors[n + 16 + 216 + 1] = make_color(8 + n * 10, 8 + n * 10, 8 + n * 10);
+ m_colors[n + 16 + 216 + 2] = make_color(8 + n * 10, 8 + n * 10, 8 + n * 10);
/* Set all other colours to black */
- for (auto n = 256 + 1; n < k_num_colors + 1; ++n)
+ for (auto n = 256 + 2; n < k_num_colors + 2; ++n)
m_colors[n] = make_color(0, 0, 0);
}
@@ -304,6 +304,7 @@ Context::prepare(uint32_t introducer,
unsigned bg_red,
unsigned bg_green,
unsigned bg_blue,
+ bool bg_transparent,
bool private_color_registers,
double pixel_aspect) noexcept
{
@@ -315,20 +316,21 @@ Context::prepare(uint32_t introducer,
if (private_color_registers)
reset_colors();
- /* FIXMEchpe: this all seems bogus. */
- set_color(0, make_color(bg_red, bg_green, bg_blue));
- if (private_color_registers)
- set_color(param_to_color_register(0),
- make_color(fg_red, fg_green, fg_blue));
+ if (bg_transparent)
+ m_colors[0] = 0u; /* fully transparent */
+ else
+ m_colors[0] = make_color(bg_red, bg_green, bg_blue);
+
+ m_colors[1] = make_color(fg_red, fg_green, fg_blue);
/*
* DEC PPLV2 says that on entering DECSIXEL mode, the active colour
- * is set to colour to colour register 0.
- * Xterm defaults to register 3.
+ * is set to colour register 0. Xterm defaults to register 3.
+ * We use the current foreground color in our special register 1.
*/
- set_current_color(param_to_color_register(0));
+ set_current_color(1);
- /* Clear bufer, and scanline offsets */
+ /* Clear buffer and scanline offsets */
std::memset(m_scanlines_offsets, 0, sizeof(m_scanlines_offsets));
if (m_scanlines_data)
diff --git a/src/sixel-context.hh b/src/sixel-context.hh
index 8364702f..fa7d13e2 100644
--- a/src/sixel-context.hh
+++ b/src/sixel-context.hh
@@ -106,7 +106,7 @@ public:
private:
- color_t m_colors[1 + k_num_colors];
+ color_t m_colors[2 + k_num_colors];
bool m_palette_modified{false};
color_index_t m_current_color{0};
@@ -272,12 +272,12 @@ private:
{
/* Colour registers are wrapped, as per DEC documentation.
*
- * We internally reserve a register for fully transparent
- * colour, and use register 0 for it since that makes it easier
- * to initialise the buffer. Therefore the user-provided
- * registers are stored at + 1 their public number.
+ * We internally reserve registers 0 and 1 for the background
+ * and foreground colors, the buffer being initialized to 0.
+ * Therefore the user-provided registers are stored at + 2 their
+ * public number.
*/
- return (param & (k_num_colors - 1)) + 1;
+ return (param & (k_num_colors - 1)) + 2;
}
inline constexpr color_t
@@ -627,6 +627,7 @@ public:
unsigned bg_red,
unsigned bg_green,
unsigned bg_blue,
+ bool bg_transparent,
bool private_color_registers,
double pixel_aspect = 1.0) noexcept;
diff --git a/src/sixel-test.cc b/src/sixel-test.cc
index e91c2cd7..d1e0f1db 100644
--- a/src/sixel-test.cc
+++ b/src/sixel-test.cc
@@ -40,6 +40,12 @@ using ParseStatus = vte::sixel::Parser::ParseStatus;
// Parser tests
+static inline constexpr auto
+param_to_color_register(unsigned reg)
+{
+ return reg + 2; /* Public colour registers start at 2 */
+}
+
static char const*
cmd_to_str(Command command)
{
@@ -1026,6 +1032,7 @@ parse_image(C& context,
context.prepare(0x50 /* C0 DCS */,
fg_red, fg_green, fg_blue,
bg_red, bg_green, bg_blue,
+ false /* bg transparent */,
private_color_registers);
auto str_st = std::string{str};
@@ -1050,7 +1057,8 @@ parse_image(C& context,
parse_image(context, ItemStringifier(items).string(),
fg_red, fg_green, fg_blue,
bg_red, bg_green, bg_blue,
- private_color_registers, line);
+ private_color_registers,
+ line);
}
template<class C>
@@ -1442,7 +1450,7 @@ test_context_image_stride(void)
assert_image_dimensions(context, 2, 12);
auto data = pixels.get();
- auto const reg = 1 + 1; /* Colour registers start at 1 */
+ auto const reg = param_to_color_register(1);
for (auto y = 0u; y < context.image_height(); ++y) {
for (auto x = 0u; x < context.image_width(); ++x)
@@ -1490,10 +1498,10 @@ test_context_image_palette(void)
unsigned b) constexpr noexcept -> Context::color_t
{
if constexpr (std::endian::native == std::endian::little) {
- return b | g << 8 | r << 16 | 0xffu << 24 /* opaque */;
- } else if constexpr (std::endian::native == std::endian::big) {
- return 0xffu /* opaque */ | r << 8 | g << 16 | b << 24;
- } else {
+ return b | g << 8 | r << 16 | 0xffu << 24 /* opaque */;
+ } else if constexpr (std::endian::native == std::endian::big) {
+ return 0xffu /* opaque */ | r << 8 | g << 16 | b << 24;
+ } else {
__builtin_unreachable();
}
};
@@ -1521,7 +1529,7 @@ test_context_image_palette(void)
for (auto n = 0; n < context.num_colors(); ++n) {
g_assert_cmpuint(make_color_rgb(palette[n].r, palette[n].g, palette[n].b),
==,
- context.color(n + 1));
+ context.color(param_to_color_register(n)));
}
}
@@ -1537,7 +1545,7 @@ test_context_image_compositing(void)
auto data = pixels.get();
for (auto y = 0u; y < context.image_height(); ++y) {
- auto const reg = (256 + y / 3) + 1; /* registers start at 1 */
+ auto const reg = param_to_color_register((256 + y / 3));
for (auto x = 0u; x < context.image_width(); ++x)
g_assert_cmpuint(*data++, ==, reg);
}
diff --git a/src/vte.cc b/src/vte.cc
index 46fe5ef4..bb311a08 100644
--- a/src/vte.cc
+++ b/src/vte.cc
@@ -8062,6 +8062,19 @@ Terminal::determine_cursor_colors(VteCell const* cell,
fore, back, deco);
}
+void
+Terminal::resolve_normal_colors(VteCell const* cell,
+ unsigned* pfore,
+ unsigned* pback,
+ vte::color::rgb& fg,
+ vte::color::rgb& bg)
+{
+ auto deco = unsigned{};
+ determine_colors(cell, false, pfore, pback, &deco);
+ rgb_from_index<8, 8, 8>(*pfore, fg);
+ rgb_from_index<8, 8, 8>(*pback, bg);
+}
+
// FIXMEchpe this constantly removes and reschedules the timer. improve this!
bool
Terminal::text_blink_timer_callback()
diff --git a/src/vteinternal.hh b/src/vteinternal.hh
index ac7c8654..19b8c19f 100644
--- a/src/vteinternal.hh
+++ b/src/vteinternal.hh
@@ -1010,6 +1010,12 @@ public:
guint *pback,
guint *pdeco) const;
+ void resolve_normal_colors(VteCell const* cell,
+ unsigned* pfore,
+ unsigned* pback,
+ vte::color::rgb& fg,
+ vte::color::rgb& bg);
+
char *cellattr_to_html(VteCellAttr const* attr,
char const* text) const;
VteCellAttr const* char_to_cell_attr(VteCharAttributes const* attr) const;
diff --git a/src/vteseq.cc b/src/vteseq.cc
index 312bd10d..88869c13 100644
--- a/src/vteseq.cc
+++ b/src/vteseq.cc
@@ -4382,8 +4382,8 @@ Terminal::DECSIXEL(vte::parser::Sequence const& seq)
*
* Defaults:
* args[0]: 0
- * args[0]: 2 (1 for printers)
- * args[0]: no default
+ * args[1]: 2 (1 for printers)
+ * args[2]: no default
*
* References: VT330
* DEC PPLV2 ยง 5.4
@@ -4437,16 +4437,30 @@ Terminal::DECSIXEL(vte::parser::Sequence const& seq)
return false;
}
+ /* How to interpret args[1] is not entirely clear from the DEC
+ * documentation and other terminal emulators.
+ * We choose to make args[1]==1 mean to use transparent background.
+ * and treat all other values (default, 0, 2) as using the current
+ * SGR background colour. See the discussion in issue #253.
+ *
+ * Also use the current SGR foreground colour to initialise
+ * the special colour register so that SIXEL images which set
+ * no colours get a sensible default.
+ */
+ auto const transparent_bg = seq.collect1(1, 2) == 1;
+
+ auto fore = unsigned{}, back = unsigned{};
+ auto fg = vte::color::rgb{}, bg = vte::color::rgb{};
+ resolve_normal_colors(&m_color_defaults, &fore, &back, fg, bg);
+
try {
if (!m_sixel_context)
m_sixel_context = std::make_unique<vte::sixel::Context>();
- auto const fg = get_color(VTE_DEFAULT_FG);
- auto const bg = get_color(VTE_DEFAULT_BG);
-
m_sixel_context->prepare(seq.st(),
- fg->red >> 8, fg->green >> 8, fg->blue >> 8,
- bg->red >> 8, bg->green >> 8, bg->blue >> 8,
+ fg.red >> 8, fg.green >> 8, fg.blue >> 8,
+ bg.red >> 8, bg.green >> 8, bg.blue >> 8,
+ back == VTE_DEFAULT_BG || transparent_bg,
m_modes_private.XTERM_SIXEL_PRIVATE_COLOR_REGISTERS());
m_sixel_context->set_mode(mode);
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