The compositor recomposited and re-uploaded the entire screen on every pass of
its loop. At the 1280x720 the desktop actually boots into, gui_gfx_present()
memcpy'd 3.6 MB into the framebuffer per frame, and the background underneath
it was recomputed pixel by pixel every time.
Present only the damage
- Keep a RAM shadow of what the framebuffer currently holds and diff the back
buffer against it, pushing just the changed span of each row. Reading the
shadow costs a RAM access; the framebuffer write it avoids costs far more,
and the framebuffer is never read back.
- Each row is narrowed to its first and last differing pixel rather than
tracked as a set of runs: one memcpy per row keeps the loop tight, and a row
that changed in two distant places is rare enough that bridging the gap is
cheaper than the bookkeeping.
- gui_gfx_invalidate() forces a full push for when something outside the
compositor owns the screen, which the desktop calls on entry and on exit
around the framebuffer console.
Cache the wallpaper
- The vertical gradient, the blended grid and the branding text never change
between frames, so they are painted once into a cached buffer and blitted
back per frame. The cache is keyed on resolution and the grid setting, so
toggling the grid from the context menu still repaints it.
No drawing code changed: the damage is derived from the frame itself, so every
widget, window and app keeps rendering exactly as before.
Measured in QEMU at 1280x720: an idle desktop with two windows open went from
921600 pixels per frame to 3609, about 0.4% of a full blit. A screendump of
the running desktop is unchanged -- wallpaper, grid, icons, both windows,
taskbar and cursor all render identically.
Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_0161Jh7uCEMLYEMNPsjC1LKf
The GUI terminal recognised four hardcoded strings and answered everything else
with "Executed: '<cmd>'". It now dispatches to the same LazyBox applet table and
shell builtins the kernel TTY uses, so ls, free, uname, lspci, ktest, neofetch,
sort, cd and the rest all work, with cwd tracked across commands.
LazyBox reports through printk, so before running a command the terminal
installs a printk sink and streams the output into its own scrollback:
- ANSI SGR codes become per-line colours instead of being stripped.
- CP437 box-drawing and block characters fall back to ASCII, so the colour
swatch in neofetch renders as '#' rather than a row of '?'.
- 256 lines of scrollback, command history on Up/Down, PgUp/PgDn/Home/End.
- Applets that read the keyboard directly (nano, snake, sh, top) are refused
with a pointer to the TTY, since they would block the compositor.
The window's paint and event handlers moved out of gui_apps.c into
gui/gui_terminal.c, and gui_gfx.c now draws from the shared lib/font8x8.c table
rather than its own copy.
Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01L5yKJT4Wo2cV3rfPrwY5MP
Turns the desktop from a fixed set of hand-drawn panels into a real
environment applications can be written against.
SUB-WT immediate-mode toolkit (gui/gui_widgets.c):
Buttons, labels, checkboxes, radios, sliders, list boxes, text fields, tab
bars, scrollbars, progress bars, sparklines and badges. An app feeds the WM
event into the toolkit and then calls widgets from its paint routine, so
each call both draws the control and reports what the user did with it --
no retained widget tree to keep in sync with window state.
Icons and dialogs:
gui_icons.c holds 14 16x16 palette-indexed glyphs stored as hex text, so the
art stays hand-editable and picks up theme changes for free; they scale by
integer factors and can be drawn as tint stencils. gui_dialog.c adds modal
info/warning/error/confirm dialogs that dim the desktop, take exclusive
input, word-wrap on spaces and report results through a callback.
Applications (gui/gui_apps_ext.c):
Settings (tabbed appearance/input/power), Task Manager (live process table
over task_find_by_pid with memory and heap gauges), Kernel Log viewer (reads
the dmesg ring, strips ANSI, colours by severity, scrolls), KTest Runner
(drives the in-kernel suites and reports 21/21 with timing), Clock & Calendar
(Zeller's congruence month grid) and a Text Editor.
Window manager (gui/gui_wm.c):
Minimize/maximize/restore buttons, a corner resize grip, edge snapping, tile
and cascade layouts, F5-F9 shortcuts, title truncation, and index-based
enumeration so the taskbar no longer assumes window ids stay dense.
Desktop shell (gui/gui_desktop.c):
Launcher icon grid, richer start menu, right-click context menu, taskbar
buttons that minimize and restore, and a live CPU trace in the tray.
Two interaction bugs fixed along the way:
- keyboard_get_key() blocks until a key arrives, so calling it every frame
froze the compositor; it is now gated on keyboard_has_key(), and stale
console input is drained before the first frame.
- When the desktop consumed a click, the WM's press-edge detector kept the
pre-press state and read the still-held button as a fresh press on the
next frame, stealing focus from whatever the click had just opened.
gui_wm_sync_button_state() keeps the two layers in step.
Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01L5yKJT4Wo2cV3rfPrwY5MP
- Upgrade resolution to 800x600 @ 32bpp TrueColor with Bochs/QEMU VBE LFB
- Implement full 8042 Aux PS/2 mouse controller driver on IRQ 12 (vector 44) with packet decode and bounds clamping
- Add high-definition 8x16 font rasterizer with text drop shadows for sharp typography
- Upgrade to smooth 16x24 anti-aliased cursor with dark slate outline and drop shadow
- Increase titlebars to 24px and taskbar to 32px with modern desktop styling
- Re-architect applications (SysMon, Terminal, Explorer, Calc, Paint, About) for spacious high-res display
- Create separate feature branch 'feat/gui-desktop'
- Implement double-buffered 2D graphics engine with alpha blending, gradients, rounded rects, and font rasterization in gui/gui_gfx.c and include/gui/gui_gfx.h
- Implement alpha-blended mouse pointer overlay in gui/gui_cursor.c and include/gui/gui_cursor.h
- Implement SUB-WM Window Manager with draggable titlebars, close/minimize buttons, drop shadows, and event routing in gui/gui_wm.c and include/gui/gui_wm.h
- Implement Cyberpunk/Nord desktop environment with wallpaper, taskbar, start menu popup, and system tray in gui/gui_desktop.c and include/gui/gui_desktop.h
- Implement built-in GUI apps: System Performance Monitor, GUI Terminal Emulator, File Explorer, Calculator, Paint Studio, and About dialog in gui/gui_apps.c and include/gui/gui_apps.h
- Add 'startx', 'gui', and 'desktop' applets in LazyBox suite
- Verified multi-architecture compilation across x86_64, AArch64, and ARMv8i
