Add VNC Hextile decoding

Internal

Public Access

Implements RFC 6143 SS7.7.4: rectangles announced as Hextile (type 5)
tile the update into 16x16 blocks, each either raw pixels or a
background fill plus an optional list of foreground/individually-
colored subrects, with background/foreground persisting across tiles
within one rectangle when not re-specified.

The pure byte-decode logic (tile metadata, subrect list) lives in new
src/vnc_pixel_codecs.h/.cpp, kept separate from
VncSessionBackend's wire-sequencing state machine so it's unit-testable
without a socket -- the pattern the plan calls for continuing into the
ZRLE/Tight work still ahead. Adds 5 fake-server tests covering a raw
tile, a background-only solid fill, uncoloured and individually-colored
subrects, and a 4-tile rectangle proving background persistence and
correct tile-cursor wraparound.

Verified against the live TightVNC test server (connect, frame,
cursor, clipboard all still work); that particular server always
chose Raw for the actual framebuffer content during this session, so
Hextile's real-world path isn't independently confirmed live -- the
unit tests are the primary correctness evidence for this phase.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

This commit is contained in:

ksmith

2026-09-15 20:49:08 -06:00

co-authored by

Claude Sonnet 5

parent 9dd1af21d6

commit e49fa0cf26

7 changed files with 598 additions and 6 deletions

									
										CMakeLists.txt
									
		+2
		
												View File
												
				@@ -128,6 +128,8 @@ set(ORBITHUB_SOURCES

				    src/ssh_session_backend.h

				    src/vnc_session_backend.cpp

				    src/vnc_session_backend.h

				    src/vnc_pixel_codecs.cpp

				    src/vnc_pixel_codecs.h

				    src/unsupported_session_backend.cpp

				    src/unsupported_session_backend.h

				)