SDK UI Utils

class BaseWindow : public Metavision::BaseGLFWWindow

Base class for displaying images and handling events in a window, deriving from BaseGLFWUI.

This class cannot directly be used as is, instead, one needs to instantiate one of its derived class (i.e. Window or MTWindow).

Note

Each window has its own events queue that needs to be regularly processed, either explicitly by calling BaseWindow::poll_events or implicitly by calling Window::show or MTWindow::show_async with auto_poll = true (default behavior). Events are polled from the system and push to the windows’ internal queue by calling EventLoop::poll_and_dispatch.

Warning

The constructor and destructor of this class must only be called from the main thread

Subclassed by Metavision::MTWindow, Metavision::Window

Public Types

enum class RenderMode

Color Rendering mode.

Values:

enumerator GRAY

enumerator BGR

Public Functions

virtual ~BaseWindow(): Destructor.

Warning

Must only be called from the main thread

void get_size(int &width, int &height) const

Gets the window’s current size.

Parameters

width – The window’s width
height – The window’s height

RenderMode get_rendering_mode() const

Gets the window’s color rendering mode.

Returns: The window’s color rendering mode (Either RenderMode::GRAY or RenderMode::BGR)

void set_keyboard_callback(const KeyCallback &cb)

Sets a callback that will be called when a key is pressed.

Note

See GLFW’s documentation (GLFWkeyfun) for more information

Warning

Due to a GLFW’s limitation, this callback returns key codes corresponding to the standard US keyboard layout. However, keys corresponding to unicode characters are mapped internally to match the current keyboard layout.

Parameters: cb – The callback to call on a key event

void set_mouse_callback(const MouseCallback &cb)

Sets a callback that will be called when a mouse’s button is pressed.

Note

See GLFW’s documentation (GLFWmousebuttonfun) for more information

Parameters: cb – The callback to call on a mouse event

void set_cursor_pos_callback(const CursorPosCallback &cb)

Sets a callback that will be called when the mouse’s cursor moves on the current window.

Note

See GLFW’s documentation (GLFWcursorposfun) for more information

Parameters: cb – The callback to call on a mouse cursor event

void poll_events(): Dequeues events in this window’s queue and calls corresponding callbacks.

Note

Calling this method is not mandatory when Window::show and MTWindow::show_async are called with auto_poll = true (i.e. default behavior). However, when the image to display is somehow generated from input events (e.g. drawing ROIs from mouse inputs), then it might be useful to call this method before both generating the image and calling Window::show or MTWindow::show_async (with auto_poll = false) to reduce the latency between the moment when the events are generated and the moment when the image is actually displayed.

Warning

The callbacks are called in the same thread as this method’s calling one. This means that if this method is called from a different thread than the one calling Window::show or MTWindow::show_async, a special care must be taken, in the callbacks, to avoid concurrency problems.

class EventLoop

A static class used to dispatch system events to the windows they belong to.

Public Static Functions

static void poll_and_dispatch(std::int64_t sleep_time_ms = 0)

Polls events from the system and pushes them into the corresponding windows’ internal queue.

Warning

Must only be called from the main thread

Parameters: sleep_time_ms – Amount of time in ms this call will wait after polling and dispatching the events

class MTWindow : public Metavision::BaseWindow 

Window using its own rendering thread to render images.

Images are displayed at a fixed frequency (i.e. the screen’s refresh one) by the internal rendering thread.

Warning

The constructor and destructor of this class must only be called from the main thread

Public Functions

MTWindow(const std::string &title, int width, int height, RenderMode mode)

Constructor.

Warning

Must only be called from the main thread

Parameters

title – The window’s title
width – Width of the window at starting time (can be resized later on) and width of the images that will be displayed
height – Height of the window at starting time (can be resized later on) and height of the images that will be displayed
mode – The color rendering mode (i.e. either GRAY or BGR). Cannot be modified.

virtual ~MTWindow(): Destructor.

Warning

Must only be called from the main thread

void show_async(cv::Mat &image, bool auto_poll = true)

Asynchronously displays an image.

Here asynchronously means that the image is not immediately displayed, but will be done later on by the internal rendering thread. This window uses a front/back buffers mechanism to avoid copying images.

Warning

If auto_poll is True, the events are processed in this method’s calling thread, not in the internal rendering one.

Parameters

image – The image to display. The image is passed as a non constant reference in order to be swapped with the front buffer and thus avoid useless copies.
auto_poll – If True, events in this window’s queue are dequeued and processed. If false, BaseWindow::poll_events must explicitly be called.

class Window : public Metavision::BaseWindow 

A window that can be used to display images from any thread.

This window has no internal rendering thread, meaning that the images are displayed at the same frequency as the one of the Window::show method.

Warning

The constructor and destructor of this class must only be called from the main thread

Public Functions

Window(const std::string &title, int width, int height, RenderMode mode)

Constructs a new Window.

Warning

Must only be called from the main thread

Parameters

title – The window’s title
width – Width of the window at starting time (can be resized later on) and width of the images that will be displayed
height – Height of the window at starting time (can be resized later on) and height of the images that will be displayed
mode – The color rendering mode (i.e. either GRAY or BGR). Cannot be modified.

virtual ~Window(): Destructor.

Warning

Must only be called from the main thread

void show(const cv::Mat &image, bool auto_poll = true)

Displays an image.

Parameters

image – The image to display
auto_poll – If True, events in this window’s queue are dequeued and processed. If false, BaseWindow::poll_events must explicitly be called.

enum Metavision::UIAction

Values:

enumerator RELEASE

enumerator PRESS

enumerator REPEAT

enum Metavision::UIMouseButton

Ids of the mouse buttons that can be triggered through the User Interface.

Values:

enumerator MOUSE_BUTTON_1

enumerator MOUSE_BUTTON_2

enumerator MOUSE_BUTTON_3

enumerator MOUSE_BUTTON_4

enumerator MOUSE_BUTTON_5

enumerator MOUSE_BUTTON_6

enumerator MOUSE_BUTTON_7

enumerator MOUSE_BUTTON_8

enumerator MOUSE_BUTTON_LAST

enumerator MOUSE_BUTTON_LEFT

enumerator MOUSE_BUTTON_RIGHT

enumerator MOUSE_BUTTON_MIDDLE

enum Metavision::UIKeyEvent

Ids of the keyboard events that can be triggered through the User Interface.

Values:

enumerator KEY_UNKNOWN

enumerator KEY_SPACE

enumerator KEY_APOSTROPHE

enumerator KEY_COMMA

enumerator KEY_MINUS

enumerator KEY_PERIOD

enumerator KEY_SLASH

enumerator KEY_0

enumerator KEY_1

enumerator KEY_2

enumerator KEY_3

enumerator KEY_4

enumerator KEY_5

enumerator KEY_6

enumerator KEY_7

enumerator KEY_8

enumerator KEY_9

enumerator KEY_SEMICOLON

enumerator KEY_EQUAL

enumerator KEY_A

enumerator KEY_B

enumerator KEY_C

enumerator KEY_D

enumerator KEY_E

enumerator KEY_F

enumerator KEY_G

enumerator KEY_H

enumerator KEY_I

enumerator KEY_J

enumerator KEY_K

enumerator KEY_L

enumerator KEY_M

enumerator KEY_N

enumerator KEY_O

enumerator KEY_P

enumerator KEY_Q

enumerator KEY_R

enumerator KEY_S

enumerator KEY_T

enumerator KEY_U

enumerator KEY_V

enumerator KEY_W

enumerator KEY_X

enumerator KEY_Y

enumerator KEY_Z

enumerator KEY_LEFT_BRACKET

enumerator KEY_BACKSLASH

enumerator KEY_RIGHT_BRACKET

enumerator KEY_GRAVE_ACCENT

enumerator KEY_WORLD_1

enumerator KEY_WORLD_2

enumerator KEY_ESCAPE

enumerator KEY_ENTER

enumerator KEY_TAB

enumerator KEY_BACKSPACE

enumerator KEY_INSERT

enumerator KEY_DELETE

enumerator KEY_RIGHT

enumerator KEY_LEFT

enumerator KEY_DOWN

enumerator KEY_UP

enumerator KEY_PAGE_UP

enumerator KEY_PAGE_DOWN

enumerator KEY_HOME

enumerator KEY_END

enumerator KEY_CAPS_LOCK

enumerator KEY_SCROLL_LOCK

enumerator KEY_NUM_LOCK

enumerator KEY_PRINT_SCREEN

enumerator KEY_PAUSE

enumerator KEY_F1

enumerator KEY_F2

enumerator KEY_F3

enumerator KEY_F4

enumerator KEY_F5

enumerator KEY_F6

enumerator KEY_F7

enumerator KEY_F8

enumerator KEY_F9

enumerator KEY_F10

enumerator KEY_F11

enumerator KEY_F12

enumerator KEY_F13

enumerator KEY_F14

enumerator KEY_F15

enumerator KEY_F16

enumerator KEY_F17

enumerator KEY_F18

enumerator KEY_F19

enumerator KEY_F20

enumerator KEY_F21

enumerator KEY_F22

enumerator KEY_F23

enumerator KEY_F24

enumerator KEY_F25

enumerator KEY_KP_0

enumerator KEY_KP_1

enumerator KEY_KP_2

enumerator KEY_KP_3

enumerator KEY_KP_4

enumerator KEY_KP_5

enumerator KEY_KP_6

enumerator KEY_KP_7

enumerator KEY_KP_8

enumerator KEY_KP_9

enumerator KEY_KP_DECIMAL

enumerator KEY_KP_DIVIDE

enumerator KEY_KP_MULTIPLY

enumerator KEY_KP_SUBTRACT

enumerator KEY_KP_ADD

enumerator KEY_KP_ENTER

enumerator KEY_KP_EQUAL

enumerator KEY_LEFT_SHIFT

enumerator KEY_LEFT_CONTROL

enumerator KEY_LEFT_ALT

enumerator KEY_LEFT_SUPER

enumerator KEY_RIGHT_SHIFT

enumerator KEY_RIGHT_CONTROL

enumerator KEY_RIGHT_ALT

enumerator KEY_RIGHT_SUPER

enumerator KEY_MENU

enumerator KEY_LAST