Crime-Scene (For the Bleed Kernel)

Crime-Scene is the desktop for Bleed. it runs in usermode as one program, the kernel knows nothing about windows. as the good lord intended

Run crime-scene with no desktop up and it is the desktop, run it again while one is up and all it does is ask for another terminal.

Crime Scene will not start automatically, it is very important that Verdict Starts first as Bleed kinda depends on it, if crime scene starts first expect the unexpected.

Features

• Start menu for launching programs
• Taskbar buttons for windows
• Clock, battery and a low memory warning in the tray
• Dragging, resizing, minimising and maximising windows
• Alt Tab to go round the windows
• Terminal Windows with Verdict
• Cursor Locking Semantics
• Window events
• TrueType fonts from /initrd/fonts
• PNG wallpaper, scaled to cover the screen
• Ctrl Alt Backspace to quit back to tty mode

Using the API

Programs talk to the desktop with libcrime.a, the header is crime/crime.h. Add -I<Crime-Scene>/include and link bin/libcrime.a before blibc.

#include <crime/crime.h>

cs_window_t *win = cs_window_open(320, 200, "Window Title");
if (!win)
    return 1;   // theres no desktop

for (int i = 0; i < win->pitch * win->height; i++)
    win->pixels[i] = 0x2B2B2F;
cs_window_commit(win, 0, 0, win->width, win->height);

cs_event_t ev;
while (cs_event_wait(&ev, -1)) {
    if (ev.type == CS_EV_CLOSE_REQUEST)
        break;
}
cs_window_close(win);

Nothing shows up until you commit, and closing is up to you. the close button only sends the event.

Functions

Function	Args	Return value	Description
cs_connect	N/A	0, or -1 if there isnt a desktop	Find the running desktop. the others do this for you
cs_window_open	int width, int height, const char *title	cs_window_t*, NULL if it failed	A new window. CS_SIZE_DEFAULT (0) for either size leaves it up to the desktop
cs_window_close	cs_window_t *win	N/A	Close the window and unmap its pixels
cs_window_commit	cs_window_t *win, int x, int y, int w, int h	N/A	Tell the desktop that part of the window changed
cs_window_move	cs_window_t *win, int x, int y	N/A	Move the window on the screen
cs_window_resize	cs_window_t *win, int width, int height	N/A	Ask for a different size. it happens when the CS_EV_RESIZE turns up, and not at all while maximised
cs_pointer_lock	cs_window_t *win, int on	N/A	Hide the pointer and get raw movement instead of positions
cs_event_wait	cs_event_t *ev, int timeout_ms	1 with an event, 0 if the timeout ran out	Wait for the next event. a negative timeout waits forever
cs_terminal_open	const char *cwd	0 once its been asked	A new terminal window, the shell starts in cwd (or wherever the desktop is if its NULL)

A program can have 16 windows open at once. maximum

The pointer lock only holds while the window has the focus, and the user can always take it back with Alt Tab. it stays free after that until they click in the window again.

Types

cs_window_t

Type	Name	Description
uint32_t	id	The desktops name for the window
int	width	Width of the window in pixels
int	height	Height of the window in pixels
int	pitch	Pixels from one row to the next, can be more than width
uint32_t*	pixels	0x00RRGGBB, draw here then commit
uint64_t	shm	The librarys own, leave it alone
uint32_t	serial	The librarys own, leave it alone

The size is whats inside the frame, the title bar and border are the desktops and arent part of it.

Always step rows by pitch and not width, the buffer is made bigger than asked for so a small resize doesnt need a new one and allocating memory for a small resize is silly

cs_event_t

Every event is the same struct (cs_msg_t), which fields mean anything depends on type.

Type	Name	Description
uint32_t	type	One of the CS_EV_* below
uint32_t	window	The id of the window its for
int32_t	x, y	Pointer position or movement
int32_t	w, h	New size
uint32_t	buttons	CS_BUTTON_LEFT, CS_BUTTON_RIGHT, CS_BUTTON_MIDDLE
uint32_t	focused	1 if the focus was just given, 0 if it was just lost
int32_t	pitch	New pitch
uint32_t	serial	Counts resizes
uint16_t	keycode	Keycode from the keyboard driver
uint8_t	key_action	KEY_DOWN or KEY_RELEASE
uint8_t	keymod	KEYMOD_SHIFT, KEYMOD_CTRL, KEYMOD_ALT, KEYMOD_CAPS

Events

Close request

The close button was clicked. the window stays until you close it.

Name	Description
type	Always CS_EV_CLOSE_REQUEST

Mouse

Name	Description
type	Always CS_EV_MOUSE
x, y	Position inside the window
buttons	Which buttons are down right now

There isnt a separate click event, compare buttons with the last one you got.

Mouse relative

Only while the pointer is locked.

Name	Description
type	Always CS_EV_MOUSE_RELATIVE
x, y	How far the mouse moved
buttons	Which buttons are down right now

Key

Name	Description
type	Always CS_EV_KEY
keycode	The same keycode the keyboard device gives
key_action	Pressed or released
keymod	Which modifiers are held

Resize

By the time this comes out of cs_event_wait the window already has its new size and pixels, all thats left is to draw into them and commit.

Name	Description
type	Always CS_EV_RESIZE
w, h	The new size
pitch	The new pitch

Focus

Name	Description
type	Always CS_EV_FOCUS
focused	Whether it just got the focus or just lost it