driver.video.windows¶

LVGL-based window manager.

Overview¶

This unit implements a simple window manager on top of LVGL. Each window consists of a set of LVGL objects (frame, title bar, title label, close and collapse buttons, content area, and resize grip) managed as a TWinRecord. Up to MAX_WINDOWS windows can exist simultaneously. The manager handles creation, destruction, focus, collapse/expand, and drag/resize interactions.

Dependencies¶

driver.video.lvgl
driver.hid.mouse
syslog

Constants¶

Constant	Value	Description
`MAX_WINDOWS`	`16`	Maximum simultaneous open windows
`WIN_TITLEBAR_H`	`32`	Title bar height in pixels
`WIN_MIN_W`	`160`	Minimum window width in pixels
`WIN_MIN_H`	`80`	Minimum window height in pixels
`WIN_RESIZE_GRIP`	`16`	Size of the resize grip area in the bottom-right corner
`WIN_BORDER_RAD`	`10`	Window frame corner radius in pixels

Types¶

TWinState¶

TWinState = (wsNone, wsOpen, wsCollapsed);

Current state of a window slot. wsNone means the slot is unused.

TWinRecord¶

Per-window state:

Field	Type	Description
`frame`	`Plv_obj`	Outer window container
`titlebar`	`Plv_obj`	Title bar panel
`title`	`Plv_obj`	Title label
`close_btn`	`Plv_obj`	Close button
`collapse_btn`	`Plv_obj`	Collapse/expand button
`content`	`Plv_obj`	Content area returned to callers
`resize_grip`	`Plv_obj`	Resize drag handle in bottom-right corner
`state`	`TWinState`	Current window state
`drag_x`, `drag_y`	`sint32`	Mouse offset from window origin at drag start
`resize_w`, `resize_h`	`sint32`	Window size at resize start
`owner_pid`	`uint32`	PID of the owning process (reserved for future use)

Functions and Procedures¶

createWindow¶

function createWindow(title: string; x, y, w, h: sint32): uint32;

Allocates the next free window slot, creates all LVGL objects with the specified title, position, and dimensions, and returns the window handle (slot index). Returns MAX_WINDOWS if no slot is available.

getWindowContent¶

function getWindowContent(handle: uint32): Plv_obj;

Returns the LVGL content container for the window identified by handle. Callers add their own widgets as children of this object.

getWindowFrame¶

function getWindowFrame(handle: uint32): Plv_obj;

Returns the outer frame object for the window. Used when the caller needs to position or style the window container directly.

destroyWindow¶

procedure destroyWindow(handle: uint32);

Deletes all LVGL objects for the window and marks the slot as wsNone.

focusWindow¶

procedure focusWindow(handle: uint32);

Brings the window to the front of the LVGL z-order and sets keyboard focus.

isWindowOpen¶

function isWindowOpen(handle: uint32): boolean;

Returns true if the given handle refers to a window in wsOpen or wsCollapsed state.

getWindowCount¶

function getWindowCount: uint32;

Returns the number of currently open windows (slots with state wsOpen or wsCollapsed).

Notes¶

Drag behaviour is implemented via LVGL LV_EVENT_PRESSING callbacks on the title bar: the window position is updated each frame by the delta between the current mouse position and the drag anchor recorded at LV_EVENT_PRESSED.
Resize behaviour uses the resize grip object's press/drag events in the same manner.
Collapsed windows retain their frame and title bar but hide the content area, reducing height to WIN_TITLEBAR_H.