Quin OS Demo Applications (apps/Drivers)

All apps are compiled as kernel-mode translation units (same flags, same address space as the kernel) and linked directly into build/quin_kernel.elf. They render into QWM client canvases using the QuinUI widget toolkit and direct canvas drawing.

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Application Overview

App	Directory	Window Position	Key Features
Clock	clock/	Top-right (1050, 65)	Analog face, fixed-point sin/cos, digital HH:MM:SS, blinking colon, uptime
System Monitor	sysmon/	Mid-right (840, 320)	Live PMM stats, FPS counter, thread count, VFS mounts
File Manager	filemanager/	Bottom-right (660, 390)	VFS readdir, hover rows, type/size columns
Calculator	calculator/	Bottom-left (30, 390)	4-function integer calc, 5×4 button grid
Notepad	notepad/	Bottom-centre (260, 390)	Keyboard input, word wrap, blinking block cursor
Terminal	terminal/	Centre (120, 120)	qsh built-ins, 64-line scrollback, CRT scanline effect, blinking cursor
Image Viewer	imgviewer/	Upper-centre (280, 50)	6 procedural images, Prev/Next navigation
Settings	settings/	Top-left (40, 50)	5-tab panel (Display/Sound/Input/About/Theme), sliders, checkboxes
Paint	paint/	Lower-centre (200, 180)	Mouse canvas, 16-colour palette, adjustable brush, faint grid
Music Player	musicplayer/	Right edge (600, 90)	32-bar animated visualizer, 5 tracks, play/pause/prev/next/seek

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Architecture

Each app follows this standard pattern:

// Initialisation (called once from apps_init()):
void app_xxx_init(void) {
    s_win = qwm_create("Title", x, y, w, h, QWM_FLAG_NONE);
    qui_button(s_win, ...);          // add QuinUI widgets
    qui_register_app(app_xxx_frame); // register per-frame callback
    qwm_show(s_win);
}

// Per-frame callback (called every compositor tick via qui_update → g_apps[]):
static void app_xxx_frame(void) {
    uint32_t *cvs = qwm_get_canvas(s_win);
    uint32_t  cw  = qwm_get_canvas_width(s_win);
    uint32_t  ch  = qwm_get_canvas_height(s_win);
    // read input, update state, draw into canvas, call qwm_invalidate()
}

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App Details

Clock Fixed-Point Trigonometry

Uses a precomputed 60-entry sin/cos table (scaled ×1000) to avoid floating-point (kernel is compiled with -mno-sse -mno-sse2):

tip_x = cx + (sin_t60[angle] * length) / 1000;
tip_y = cy - (cos_t60[angle] * length) / 1000;  // Y-flipped for screen coords

Time is derived from scheduler_get_ticks() (100 Hz PIT):

seconds = ticks / 100
minutes = seconds / 60
hours   = (seconds / 3600) % 12

Terminal CRT Emulation

Maintains a 64-line scrollback ring buffer (TERM_HIST). Every other pixel row is darkened by 10% to simulate a CRT scanline effect. Built-in commands: help, clear, uname, uptime, mem, echo, ls, ver.

Image Viewer Procedural Rendering

Six images generated entirely in software (no image files required):

1. Gradient Spectrum HSV hue rotation across width
2. Plasma Wave three overlapping sine-table patterns
3. Checkerboard per-square gradients
4. Color Bars SMPTE-style 8 bars
5. Mandelbrot 28-iteration fixed-point 8.24 arithmetic
6. Star Field LCG pseudo-random stars + nebula alpha blend + moon circle

Paint Mouse Drawing

Reads global mouse position via mouse_get_x/y(), converts to canvas-relative coordinates using qwm_get_canvas_screen_x/y(). Draws filled circles into a static uint32_t[300][544] bitmap; the bitmap is blitted into the canvas each frame.

Music Player Visualizer

32 frequency bars driven by a 64-entry sine table phased by scheduler_get_ticks() and the current track's BPM. Each bar is rendered with a top-to-bottom gradient (bright blue → dark blue) plus a white glow cap. Progress bar is a QUI_PROGRESSBAR widget updated via qui_set_value() each frame.

Settings Multi-Tab Panel

Five tabs (Display, Sound, Input, About, Theme) rendered via a per-frame switch(s_tab) dispatch. Tab buttons are transparent QUI_BUTTON widgets overlaid on a manually drawn tab bar. Sliders control demo values (brightness, contrast, volume, mouse speed) via qui_change_fn callbacks.

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System Monitor Live Stats

Metric	Source
CPU Uptime	scheduler_get_ticks() / 100 (seconds)
Memory Used/Free	pmm_get_stats() → used_frames × 4 KB
Thread Count	scheduler_get_thread_count()
VFS Mounts	vfs_get_mount_count()
FPS	100-frame sliding window over PIT ticks

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Initialisation Sequence (from kernel/src/main.c)

qds_init(fb_width, fb_height);   // Phase 3 Step 1    display server
qwm_init();                       // Phase 3 Step 2    window manager
qui_init();                       // Phase 3 Step 3    QuinUI + demo windows
apps_init();                      // Phase 3 Step 4 + Phase 4    all 10 apps
qwm_run();                        // event loop (never returns)

apps_init() (in apps/apps.c) registers all 10 apps in Z-order (first = bottommost):

app_sysmon_init();       // Phase 3    behind other windows
app_filemanager_init();
app_calculator_init();
app_notepad_init();
app_clock_init();        // Phase 3    topmost of P3 stack
app_settings_init();     // Phase 4
app_imgviewer_init();
app_musicplayer_init();
app_terminal_init();
app_paint_init();        // Phase 4    topmost (front)

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Notepad Keyboard Input Ordering

The Notepad reads keyboard_has_char() / keyboard_getchar() inside its frame callback, which runs via qui_update() → g_apps[]. This happens before QWM's own keyboard poll:

qwm_run() per tick:
  1. qui_update()         ← all app frame callbacks run here (notepad reads keys)
  2. process_mouse()      ← QWM drag / click handling
  3. process_keyboard()   ← Alt+F4 only (chars already consumed)
  4. qwm_composite()
  5. hlt

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Build

All app .c files are listed in C_SOURCES in the root Makefile and compiled with the same kernel flags:

apps/apps.c
apps/clock/clock.c
apps/calculator/calculator.c
apps/notepad/notepad.c
apps/filemanager/filemanager.c
apps/sysmon/sysmon.c
apps/terminal/terminal.c
apps/imgviewer/imgviewer.c
apps/settings/settings.c
apps/paint/paint.c
apps/musicplayer/musicplayer.c

Compile flags: -m64 -ffreestanding -nostdlib -mno-red-zone -mno-sse -mno-sse2 -Wall -Wextra -Werror -O2

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Author

Quin OS Team