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-rw-r--r--doc/protocols30
1 files changed, 23 insertions, 7 deletions
diff --git a/doc/protocols b/doc/protocols
index fc9ac69..d40123b 100644
--- a/doc/protocols
+++ b/doc/protocols
@@ -307,6 +307,11 @@ Conditionally required header: Bytes
24-bit colours will have this set to 1 because each
subpixel has 8 bits, 48-bit colours will have this
set to 2 because each subpixel has 16 bits
+ Allowed values are: 1, 2, 4 and 8. These values are
+ used used so that CPU:s with any endianness can be
+ trivially used as the words sizes are guaranteed to
+ be supported in C, and mixed/middle-endiannes gets
+ complicated if we go outside this.
Conditionally optional/required header: Colour
Available and optional if: `Length`-header is not used
@@ -327,9 +332,11 @@ Optional header: Use urgency
no) The icon tray may not blink
Message: Raw binary encoding of the background image, bytes
- are orders: row, pixel, channel (red, green, blue,
- then optionally alpha), subpixel value (most
- significant byte first)
+ are orders: row, pixel, channel (alpha, red, green,
+ blue), subpixel value (native CPU encoding). The
+ Alpha channel should be included but ignored if
+ `Has alpha: no`, in such as it is best to set it to
+ full.
Example image (with `Bytes: 2`, `Has alpha: no` and `Size: 3`):
sRGB(x0102, 0, 0), sRGB(0, x0304, 0), sRGB(0, 0, x0506)
@@ -337,10 +344,19 @@ Message: Raw binary encoding of the background image, bytes
sRGB(x0D0E, 0, 0), sRGB(0, x0F10, 0), sRGB(0, 0, x1112)
Encoding of example image (hexadecimal):
- 0102 0000 0000 0000 0304 0000 0000 0000 0506
- 0708 0000 0000 0000 090A 0000 0000 0000 0B0C
- 0D0E 0000 0000 0000 0F10 0000 0000 0000 1112
-
+ FFFF 0102 0000 0000 FFFF 0000 0304 0000 FFFF 0000 0000 0506
+ FFFF 0708 0000 0000 FFFF 0000 090A 0000 FFFF 0000 0000 0B0C
+ FFFF 0D0E 0000 0000 FFFF 0000 0F10 0000 FFFF 0000 0000 1112
+
+ Note that on a big-endian system this would be:
+ FF FF 02 01 00 00 00 00 FF FF 00 00 04 03 00 00 FF FF 00 00 00 00 06 05
+ FF FF 08 07 00 00 00 00 FF FF 00 00 0A 09 00 00 FF FF 00 00 00 00 0C 0B
+ FF FF 0E 0D 00 00 00 00 FF FF 00 00 10 0F 00 00 FF FF 00 00 00 00 12 11
+ (x86_64 computers are big-endian)
+
+ It is up to the networking servers to translate
+ the encoding between machines. (The host translates to big-endian
+ unless they can confirm that they have the same endianness.)
Purpose: Enable clients to be aware of the appearance of the tray,
such as colours, transparency and background image