The CImg Library - C++ Template Image Processing Toolkit
Author: David Tschumperle

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CImgDisplay Struct Reference

Allow to create windows, display images on them and manage user events (keyboard, mouse and windows events). More...

## Constructors / Destructor / Instance Management
| ~CImgDisplay ()
| Destructor. More...
| CImgDisplay ()
| Construct an empty display. More...
| CImgDisplay (const unsigned int width, const unsigned int height, const char *const title=0, const unsigned int normalization=3, const bool is_fullscreen=false, const bool is_closed=false)
| Construct a display with specified dimensions. More...
template<typename T >
| CImgDisplay (const CImg< T > &img, const char *const title=0, const unsigned int normalization=3, const bool is_fullscreen=false, const bool is_closed=false)
| Construct a display from an image. More...
template<typename T >
| CImgDisplay (const CImgList< T > &list, const char *const title=0, const unsigned int normalization=3, const bool is_fullscreen=false, const bool is_closed=false)
| Construct a display from an image list. More...
| CImgDisplay (const CImgDisplay &disp)
| Construct a display as a copy of an existing one. More...
CImgDisplay & | assign ()
| Destructor - Empty constructor [in-place version]. More...
CImgDisplay & | assign (const unsigned int width, const unsigned int height, const char *const title=0, const unsigned int normalization=3, const bool is_fullscreen=false, const bool is_closed=false)
| Construct a display with specified dimensions [in-place version].
template<typename T >
CImgDisplay & | assign (const CImg< T > &img, const char *const title=0, const unsigned int normalization=3, const bool is_fullscreen=false, const bool is_closed=false)
| Construct a display from an image [in-place version].
template<typename T >
CImgDisplay & | assign (const CImgList< T > &list, const char *const title=0, const unsigned int normalization=3, const bool is_fullscreen=false, const bool is_closed=false)
| Construct a display from an image list [in-place version].
CImgDisplay & | assign (const CImgDisplay &disp)
| Construct a display as a copy of another one [in-place version].
static CImgDisplay & | empty ()
| Return a reference to an empty display. More...

## Overloaded Operators
template<typename t >
CImgDisplay & | operator= (const CImg< t > &img)
| Display image on associated window. More...
template<typename t >
CImgDisplay & | operator= (const CImgList< t > &list)
| Display list of images on associated window. More...
CImgDisplay & | operator= (const CImgDisplay &disp)
| Construct a display as a copy of another one [in-place version]. More...
| operator bool () const
| Return `false` if display is empty, `true` otherwise. More...

## Instance Checking
bool | is_empty () const
| Return `true` if display is empty, `false` otherwise.
bool | is_closed () const
| Return `true` if display is closed (i.e. not visible on the screen), `false` otherwise. More...
bool | is_resized () const
| Return `true` if associated window has been resized on the screen, `false` otherwise.
bool | is_moved () const
| Return `true` if associated window has been moved on the screen, `false` otherwise.
bool | is_event () const
| Return `true` if any event has occured on the associated window, `false` otherwise.
bool | is_fullscreen () const
| Return `true` if current display is in fullscreen mode, `false` otherwise.
bool | is_key () const
| Return `true` if any key is being pressed on the associated window, `false` otherwise. More...
bool | is_key (const unsigned int keycode) const
| Return `true` if key specified by given keycode is being pressed on the associated window, `false` otherwise. More...
bool | is_key (const char *const keycode) const
| Return `true` if key specified by given keycode is being pressed on the associated window, `false` otherwise. More...
bool | is_key_sequence (const unsigned int *const keycodes_sequence, const unsigned int length, const bool remove_sequence=false)
| Return `true` if specified key sequence has been typed on the associated window, `false` otherwise. More...
bool | is_keyESC () const
| Return `true` if the `ESC` key is being pressed on the associated window, `false` otherwise. More...
bool | is_keyF1 () const
bool | is_keyF2 () const
bool | is_keyF3 () const
bool | is_keyF4 () const
bool | is_keyF5 () const
bool | is_keyF6 () const
bool | is_keyF7 () const
bool | is_keyF8 () const
bool | is_keyF9 () const
bool | is_keyF10 () const
bool | is_keyF11 () const
bool | is_keyF12 () const
bool | is_keyPAUSE () const
bool | is_key1 () const
bool | is_key2 () const
bool | is_key3 () const
bool | is_key4 () const
bool | is_key5 () const
bool | is_key6 () const
bool | is_key7 () const
bool | is_key8 () const
bool | is_key9 () const
bool | is_key0 () const
bool | is_keyBACKSPACE () const
bool | is_keyINSERT () const
bool | is_keyHOME () const
bool | is_keyPAGEUP () const
bool | is_keyTAB () const
bool | is_keyQ () const
bool | is_keyW () const
bool | is_keyE () const
bool | is_keyR () const
bool | is_keyT () const
bool | is_keyY () const
bool | is_keyU () const
bool | is_keyI () const
bool | is_keyO () const
bool | is_keyP () const
bool | is_keyDELETE () const
bool | is_keyEND () const
bool | is_keyPAGEDOWN () const
bool | is_keyCAPSLOCK () const
bool | is_keyA () const
bool | is_keyS () const
bool | is_keyD () const
bool | is_keyF () const
bool | is_keyG () const
bool | is_keyH () const
bool | is_keyJ () const
bool | is_keyK () const
bool | is_keyL () const
bool | is_keyENTER () const
bool | is_keySHIFTLEFT () const
bool | is_keyZ () const
bool | is_keyX () const
bool | is_keyC () const
bool | is_keyV () const
bool | is_keyB () const
bool | is_keyN () const
bool | is_keyM () const
bool | is_keySHIFTRIGHT () const
bool | is_keyARROWUP () const
bool | is_keyCTRLLEFT () const
bool | is_keyAPPLEFT () const
bool | is_keyALT () const
bool | is_keySPACE () const
bool | is_keyALTGR () const
bool | is_keyAPPRIGHT () const
bool | is_keyMENU () const
bool | is_keyCTRLRIGHT () const
bool | is_keyARROWLEFT () const
bool | is_keyARROWDOWN () const
bool | is_keyARROWRIGHT () const
bool | is_keyPAD0 () const
bool | is_keyPAD1 () const
bool | is_keyPAD2 () const
bool | is_keyPAD3 () const
bool | is_keyPAD4 () const
bool | is_keyPAD5 () const
bool | is_keyPAD6 () const
bool | is_keyPAD7 () const
bool | is_keyPAD8 () const
bool | is_keyPAD9 () const
bool | is_keyPADADD () const
bool | is_keyPADSUB () const
bool | is_keyPADMUL () const
bool | is_keyPADDIV () const

## Instance Characteristics
int | width () const
| Return display width. More...
int | height () const
| Return display height. More...
unsigned int | normalization () const
| Return normalization type of the display. More...
const char * | title () const
| Return title of the associated window as a C-string. More...
int | window_width () const
| Return width of the associated window. More...
int | window_height () const
| Return height of the associated window. More...
int | window_x () const
| Return X-coordinate of the associated window. More...
int | window_y () const
| Return Y-coordinate of the associated window. More...
int | mouse_x () const
| Return X-coordinate of the mouse pointer. More...
int | mouse_y () const
| Return Y-coordinate of the mouse pointer. More...
unsigned int | button () const
| Return current state of the mouse buttons. More...
int | wheel () const
| Return current state of the mouse wheel. More...
unsigned int | key (const unsigned int pos=0) const
| Return one entry from the pressed keys history. More...
unsigned int | released_key (const unsigned int pos=0) const
| Return one entry from the released keys history. More...
float | frames_per_second ()
| Return the current refresh rate, in frames per second. More...
static int | screen_width ()
| Return width of the screen (current resolution along the X-axis).
static int | screen_height ()
| Return height of the screen (current resolution along the Y-axis).
static unsigned int | keycode (const char *const keycode)
| Return keycode corresponding to the specified string. More...

## Window Manipulation
template<typename T >
CImgDisplay & | display (const CImg< T > &img)
| Display image on associated window. More...
template<typename T >
CImgDisplay & | display (const CImgList< T > &list, const char axis='x', const float align=0)
| Display list of images on associated window. More...
CImgDisplay & | show ()
| Show (closed) associated window on the screen. More...
CImgDisplay & | close ()
| Close (visible) associated window and make it disappear from the screen. More...
CImgDisplay & | move (const int pos_x, const int pos_y)
| Move associated window to a new location. More...
CImgDisplay & | resize (const bool force_redraw=true)
| Resize display to the size of the associated window. More...
CImgDisplay & | resize (const int width, const int height, const bool force_redraw=true)
| Resize display to the specified size. More...
template<typename T >
CImgDisplay & | resize (const CImg< T > &img, const bool force_redraw=true)
| Resize display to the size of an input image. More...
CImgDisplay & | resize (const CImgDisplay &disp, const bool force_redraw=true)
| Resize display to the size of another CImgDisplay instance. More...
CImgDisplay & | set_normalization (const unsigned int normalization)
| Set normalization type. More...
CImgDisplay & | set_title (const char *const format,...)
| Set title of the associated window. More...
CImgDisplay & | set_fullscreen (const bool is_fullscreen, const bool force_redraw=true)
| Enable or disable fullscreen mode. More...
CImgDisplay & | toggle_fullscreen (const bool force_redraw=true)
| Toggle fullscreen mode. More...
CImgDisplay & | show_mouse ()
| Show mouse pointer. More...
CImgDisplay & | hide_mouse ()
| Hide mouse pointer. More...
CImgDisplay & | set_mouse (const int pos_x, const int pos_y)
| Move mouse pointer to a specified location. More...
CImgDisplay & | set_button ()
| Simulate a mouse button release event. More...
CImgDisplay & | set_button (const unsigned int button, const bool is_pressed=true)
| Simulate a mouse button press or release event. More...
CImgDisplay & | set_wheel ()
| Flush all mouse wheel events. More...
CImgDisplay & | set_wheel (const int amplitude)
| Simulate a wheel event. More...
CImgDisplay & | set_key ()
| Flush all key events. More...
CImgDisplay & | set_key (const unsigned int keycode, const bool is_pressed=true)
| Simulate a keyboard press/release event. More...
CImgDisplay & | flush ()
| Flush all display events. More...
CImgDisplay & | wait ()
| Wait for any user event occuring on the current display.
CImgDisplay & | wait (const unsigned int milliseconds)
| Wait for a given number of milliseconds since the last call to wait(). More...
template<typename T >
CImgDisplay & | render (const CImg< T > &img)
| Render image into internal display buffer. More...
CImgDisplay & | paint ()
| Paint internal display buffer on associated window. More...
template<typename T >
const CImgDisplay & | snapshot (CImg< T > &img) const
| Take a snapshot of the associated window content. More...
static void | wait (CImgDisplay &disp1)
| Wait for any event occuring on the display `disp1`.
static void | wait (CImgDisplay &disp1, CImgDisplay &disp2)
| Wait for any event occuring either on the display `disp1` or `disp2`.
static void | wait (CImgDisplay &disp1, CImgDisplay &disp2, CImgDisplay &disp3)
| Wait for any event occuring either on the display `disp1`, `disp2` or `disp3`.
static void | wait (CImgDisplay &disp1, CImgDisplay &disp2, CImgDisplay &disp3, CImgDisplay &disp4)
| Wait for any event occuring either on the display `disp1`, `disp2`, `disp3` or `disp4`.
static void | wait (CImgDisplay &disp1, CImgDisplay &disp2, CImgDisplay &disp3, CImgDisplay &disp4, CImgDisplay &disp5)
| Wait for any event occuring either on the display `disp1`, `disp2`, `disp3`, `disp4` or `disp5`.
static void | wait (CImgDisplay &disp1, CImgDisplay &disp2, CImgDisplay &disp3, CImgDisplay &disp4, CImgDisplay &disp5, CImgDisplay &disp6)
| Wait for any event occuring either on the display `disp1`, `disp2`, `disp3`, `disp4`, ... `disp6`.
static void | wait (CImgDisplay &disp1, CImgDisplay &disp2, CImgDisplay &disp3, CImgDisplay &disp4, CImgDisplay &disp5, CImgDisplay &disp6, CImgDisplay &disp7)
| Wait for any event occuring either on the display `disp1`, `disp2`, `disp3`, `disp4`, ... `disp7`.
static void | wait (CImgDisplay &disp1, CImgDisplay &disp2, CImgDisplay &disp3, CImgDisplay &disp4, CImgDisplay &disp5, CImgDisplay &disp6, CImgDisplay &disp7, CImgDisplay &disp8)
| Wait for any event occuring either on the display `disp1`, `disp2`, `disp3`, `disp4`, ... `disp8`.
static void | wait (CImgDisplay &disp1, CImgDisplay &disp2, CImgDisplay &disp3, CImgDisplay &disp4, CImgDisplay &disp5, CImgDisplay &disp6, CImgDisplay &disp7, CImgDisplay &disp8, CImgDisplay &disp9)
| Wait for any event occuring either on the display `disp1`, `disp2`, `disp3`, `disp4`, ... `disp9`.
static void | wait (CImgDisplay &disp1, CImgDisplay &disp2, CImgDisplay &disp3, CImgDisplay &disp4, CImgDisplay &disp5, CImgDisplay &disp6, CImgDisplay &disp7, CImgDisplay &disp8, CImgDisplay &disp9, CImgDisplay &disp10)
| Wait for any event occuring either on the display `disp1`, `disp2`, `disp3`, `disp4`, ... `disp10`.
static void | wait_all ()
| Wait for any window event occuring in any opened CImgDisplay.

## Detailed Description

Allow to create windows, display images on them and manage user events (keyboard, mouse and windows events).

CImgDisplay methods rely on a low-level graphic library to perform: it can be either X-Window (X11, for Unix-based systems) or GDI32 (for Windows-based systems). If both libraries are missing, CImgDisplay will not be able to display images on screen, and will enter a minimal mode where warning messages will be outputed each time the program is trying to call one of the CImgDisplay method.

The configuration variable `cimg_display` tells about the graphic library used. It is set automatically by `CImg` when one of these graphic libraries has been detected. But, you can override its value if necessary. Valid choices are:

- 0: Disable display capabilities.
- 1: Use X-Window (X11) library.
- 2: Use GDI32 library.

Remember to link your program against X11 or GDI32 libraries if you use CImgDisplay.

## Constructor & Destructor Documentation

~CImgDisplay | ( |  | ) |

Destructor.

Note
  If the associated window is visible on the screen, it is closed by the call to the destructor.

CImgDisplay | ( |  | ) |

Construct an empty display.

Note
  Constructing an empty CImgDisplay instance does not make a window appearing on the screen, until display of valid data is performed.

Example
  CImgDisplay disp; // Does actually nothing.
  ...
  disp.display(img); // Construct new window and display image in it.

CImgDisplay | ( | const unsigned int | width,
|  | const unsigned int | height,
|  | const char *const | title = `0`,
|  | const unsigned int | normalization = `3`,
|  | const bool | is_fullscreen = `false`,
|  | const bool | is_closed = `false`
| ) |  |

Construct a display with specified dimensions.

Parameters

  width | Window width.
  height | Window height.
  title | Window title.
  normalization | Normalization type (`0`=none, `1`=always, `2`=once, `3`=pixel type-dependent, see normalization()).
  is_fullscreen | Tells if fullscreen mode is enabled.
  is_closed | Tells if associated window is initially visible or not.

Note
  A black background is initially displayed on the associated window.

CImgDisplay | ( | const CImg< T > & | img,
|  | const char *const | title = `0`,
|  | const unsigned int | normalization = `3`,
|  | const bool | is_fullscreen = `false`,
|  | const bool | is_closed = `false`
| ) |  |
| explicit

Construct a display from an image.

Parameters

  img | Image used as a model to create the window.
  title | Window title.
  normalization | Normalization type (`0`=none, `1`=always, `2`=once, `3`=pixel type-dependent, see normalization()).
  is_fullscreen | Tells if fullscreen mode is enabled.
  is_closed | Tells if associated window is initially visible or not.

Note
  The pixels of the input image are initially displayed on the associated window.

CImgDisplay | ( | const CImgList< T > & | list,
|  | const char *const | title = `0`,
|  | const unsigned int | normalization = `3`,
|  | const bool | is_fullscreen = `false`,
|  | const bool | is_closed = `false`
| ) |  |
| explicit

Construct a display from an image list.

Parameters

  list | The images list to display.
  title | Window title.
  normalization | Normalization type (`0`=none, `1`=always, `2`=once, `3`=pixel type-dependent, see normalization()).
  is_fullscreen | Tells if fullscreen mode is enabled.
  is_closed | Tells if associated window is initially visible or not.

Note
  All images of the list, appended along the X-axis, are initially displayed on the associated window.

CImgDisplay | ( | const CImgDisplay & | disp | ) |

Construct a display as a copy of an existing one.

Parameters

  disp | Display instance to copy.

Note
  The pixel buffer of the input window is initially displayed on the associated window.

## Member Function Documentation

CImgDisplay& assign | ( |  | ) |

Destructor - Empty constructor [in-place version].

Note
  Replace the current instance by an empty display.

static CImgDisplay& empty | ( |  | ) |
| static

Return a reference to an empty display.

Note
  Can be useful for writing function prototypes where one of the argument (of type CImgDisplay&) must have a default value.

Example
  void foo(CImgDisplay& disp=CImgDisplay::empty());

CImgDisplay& operator= | ( | const CImg< t > & | img | ) |

Display image on associated window.

Note
  `disp = img` is equivalent to `disp.display(img)`.

CImgDisplay& operator= | ( | const CImgList< t > & | list | ) |

Display list of images on associated window.

Note
  `disp = list` is equivalent to `disp.display(list)`.

CImgDisplay& operator= | ( | const CImgDisplay & | disp | ) |

Construct a display as a copy of another one [in-place version].

Note
  Equivalent to assign(const CImgDisplay&).

operator bool | ( |  | ) | const

Return `false` if display is empty, `true` otherwise.

Note
  `if (disp) { ... }` is equivalent to `if (!disp.is_empty()) { ... }`.

bool is_closed | ( |  | ) | const

Return `true` if display is closed (i.e. not visible on the screen), `false` otherwise.

Note
  - When a user physically closes the associated window, the display is set to closed.
  - A closed display is not destroyed. Its associated window can be show again on the screen using show().

bool is_key | ( |  | ) | const

Return `true` if any key is being pressed on the associated window, `false` otherwise.

Note
  The methods below do the same only for specific keys.

bool is_key | ( | const unsigned int | keycode | ) | const

Return `true` if key specified by given keycode is being pressed on the associated window, `false` otherwise.

Parameters

  keycode | Keycode to test.

Note
  Keycode constants are defined in the cimg namespace and are architecture-dependent. Use them to ensure your code stay portable (see cimg::keyESC).

Example
  CImgDisplay disp(400,400);
  while (!disp.is_closed()) {
  if (disp.key(cimg::keyTAB)) { ... } // Equivalent to 'if (disp.is_keyTAB())'.
  disp.wait();
  }

bool is_key | ( | const char *const | keycode | ) | const

Return `true` if key specified by given keycode is being pressed on the associated window, `false` otherwise.

Parameters

  keycode | C-string containing the keycode label of the key to test.

Note
  Use it when the key you want to test can be dynamically set by the user.

Example
  CImgDisplay disp(400,400);
  const char *const keycode = "TAB";
  while (!disp.is_closed()) {
  if (disp.is_key(keycode)) { ... } // Equivalent to 'if (disp.is_keyTAB())'.
  disp.wait();
  }

bool is_key_sequence | ( | const unsigned int *const | keycodes_sequence,
|  | const unsigned int | length,
|  | const bool | remove_sequence = `false`
| ) |  |

Return `true` if specified key sequence has been typed on the associated window, `false` otherwise.

Parameters

  keycodes_sequence | Buffer of keycodes to test.
  length | Number of keys in the `keycodes_sequence` buffer.
  remove_sequence | Tells if the key sequence must be removed from the key history, if found.

Note
  Keycode constants are defined in the cimg namespace and are architecture-dependent. Use them to ensure your code stay portable (see cimg::keyESC).

Example
  CImgDisplay disp(400,400);
  const unsigned int key_seq[] = { cimg::keyCTRLLEFT, cimg::keyD };
  while (!disp.is_closed()) {
  if (disp.is_key_sequence(key_seq,2)) { ... } // Test for the 'CTRL+D' keyboard event.
  disp.wait();
  }

bool is_keyESC | ( |  | ) | const

Return `true` if the `ESC` key is being pressed on the associated window, `false` otherwise.

Note
  Similar methods exist for all keys managed by `CImg` (see cimg::keyESC).

int width | ( |  | ) | const

Return display width.

Note
  The width of the display (i.e. the width of the pixel data buffer associated to the CImgDisplay instance) may be different from the actual width of the associated window.

int height | ( |  | ) | const

Return display height.

Note
  The height of the display (i.e. the height of the pixel data buffer associated to the CImgDisplay instance) may be different from the actual height of the associated window.

unsigned int normalization | ( |  | ) | const

Return normalization type of the display.

The normalization type tells about how the values of an input image are normalized by the CImgDisplay to be correctly displayed. The range of values for pixels displayed on screen is `[0,255]`. If the range of values of the data to display is different, a normalization may be required for displaying the data in a correct way. The normalization type can be one of:

- `0`: Value normalization is disabled. It is then assumed that all input data to be displayed by the CImgDisplay instance have values in range `[0,255]`.
- `1`: Value normalization is always performed (this is the default behavior). Before displaying an input image, its values will be (virtually) stretched in range `[0,255]`, so that the contrast of the displayed pixels will be maximum. Use this mode for images whose minimum and maximum values are not prescribed to known values (e.g. float-valued images). Note that when normalized versions of images are computed for display purposes, the actual values of these images are not modified.
- `2`: Value normalization is performed once (on the first image display), then the same normalization coefficients are kept for next displayed frames.
- `3`: Value normalization depends on the pixel type of the data to display. For integer pixel types, the normalization is done regarding the minimum/maximum values of the type (no normalization occurs then for `unsigned char`). For float-valued pixel types, the normalization is done regarding the minimum/maximum value of the image data instead.

const char* title | ( |  | ) | const

Return title of the associated window as a C-string.

Note
  Window title may be not visible, depending on the used window manager or if the current display is in fullscreen mode.

int window_width | ( |  | ) | const

Return width of the associated window.

Note
  The width of the display (i.e. the width of the pixel data buffer associated to the CImgDisplay instance) may be different from the actual width of the associated window.

int window_height | ( |  | ) | const

Return height of the associated window.

Note
  The height of the display (i.e. the height of the pixel data buffer associated to the CImgDisplay instance) may be different from the actual height of the associated window.

int window_x | ( |  | ) | const

Return X-coordinate of the associated window.

Note
  The returned coordinate corresponds to the location of the upper-left corner of the associated window.

int window_y | ( |  | ) | const

Return Y-coordinate of the associated window.

Note
  The returned coordinate corresponds to the location of the upper-left corner of the associated window.

int mouse_x | ( |  | ) | const

Return X-coordinate of the mouse pointer.

Note
  - If the mouse pointer is outside window area, `-1` is returned.
  - Otherwise, the returned value is in the range [0,width()-1].

int mouse_y | ( |  | ) | const

Return Y-coordinate of the mouse pointer.

Note
  - If the mouse pointer is outside window area, `-1` is returned.
  - Otherwise, the returned value is in the range [0,height()-1].

unsigned int button | ( |  | ) | const

Return current state of the mouse buttons.

Note
  Three mouse buttons can be managed. If one button is pressed, its corresponding bit in the returned value is set:
  - bit `0` (value `0x1`): State of the left mouse button.
  - bit `1` (value `0x2`): State of the right mouse button.
  - bit `2` (value `0x4`): State of the middle mouse button.

Several bits can be activated if more than one button are pressed at the same time.

Example
  CImgDisplay disp(400,400);
  while (!disp.is_closed()) {
  if (disp.button()&1) { // Left button clicked.
  ...
  }
  if (disp.button()&2) { // Right button clicked.
  ...
  }
  if (disp.button()&4) { // Middle button clicked.
  ...
  }
  disp.wait();
  }

int wheel | ( |  | ) | const

Return current state of the mouse wheel.

Note
  - The returned value can be positive or negative depending on whether the mouse wheel has been scrolled forward or backward.
  - Scrolling the wheel forward add `1` to the wheel value.
  - Scrolling the wheel backward substract `1` to the wheel value.
  - The returned value cumulates the number of forward of backward scrolls since the creation of the display, or since the last reset of the wheel value (using set_wheel()). It is strongly recommended to quickly reset the wheel counter when an action has been performed regarding the current wheel value. Otherwise, the returned wheel value may be for instance `0` despite the fact that many scrolls have been done (as many in forward as in backward directions).

Example
  CImgDisplay disp(400,400);
  while (!disp.is_closed()) {
  if (disp.wheel()) {
  int counter = disp.wheel(); // Read the state of the mouse wheel.
  ... // Do what you want with 'counter'.
  disp.set_wheel(); // Reset the wheel value to 0.
  }
  disp.wait();
  }

unsigned int key | ( | const unsigned int | pos = `0` | ) | const

Return one entry from the pressed keys history.

Parameters

  pos | Indice to read from the pressed keys history (indice `0` corresponds to latest entry).

Returns
  Keycode of a pressed key or `0` for a released key.

Note
  - Each CImgDisplay stores a history of the pressed keys in a buffer of size `128`. When a new key is pressed, its keycode is stored in the pressed keys history. When a key is released, `0` is put instead. This means that up to the 64 last pressed keys may be read from the pressed keys history. When a new value is stored, the pressed keys history is shifted so that the latest entry is always stored at position `0`.
  - Keycode constants are defined in the cimg namespace and are architecture-dependent. Use them to ensure your code stay portable (see cimg::keyESC).

unsigned int released_key | ( | const unsigned int | pos = `0` | ) | const

Return one entry from the released keys history.

Parameters

  pos | Indice to read from the released keys history (indice `0` corresponds to latest entry).

Returns
  Keycode of a released key or `0` for a pressed key.

Note
  - Each CImgDisplay stores a history of the released keys in a buffer of size `128`. When a new key is released, its keycode is stored in the pressed keys history. When a key is pressed, `0` is put instead. This means that up to the 64 last released keys may be read from the released keys history. When a new value is stored, the released keys history is shifted so that the latest entry is always stored at position `0`.
  - Keycode constants are defined in the cimg namespace and are architecture-dependent. Use them to ensure your code stay portable (see cimg::keyESC).

static unsigned int keycode | ( | const char *const | keycode | ) |
| static

Return keycode corresponding to the specified string.

Note
  Keycode constants are defined in the cimg namespace and are architecture-dependent. Use them to ensure your code stay portable (see cimg::keyESC).

Example
  const unsigned int keyTAB = CImgDisplay::keycode("TAB"); // Return cimg::keyTAB.

float frames_per_second | ( |  | ) |

Return the current refresh rate, in frames per second.

Note
  Returns a significant value when the current instance is used to display successive frames. It measures the delay between successive calls to frames_per_second().

CImgDisplay& display | ( | const CImg< T > & | img | ) |

Display image on associated window.

Parameters

  img | Input image to display.

Note
  This method returns immediately.

CImgDisplay& display | ( | const CImgList< T > & | list,
|  | const char | axis = `'x'`,
|  | const float | align = `0`
| ) |  |

Display list of images on associated window.

Parameters

  list | List of images to display.
  axis | Axis used to append the images along, for the visualization (can be `x`, `y`, `z` or `c`).
  align | Relative position of aligned images when displaying lists with images of different sizes (`0` for upper-left, `0.5` for centering and `1` for lower-right).

Note
  This method returns immediately.

CImgDisplay& show | ( |  | ) |

Show (closed) associated window on the screen.

Note
  - Force the associated window of a display to be visible on the screen, even if it has been closed before.
  - Using show() on a visible display does nothing.

CImgDisplay& close | ( |  | ) |

Close (visible) associated window and make it disappear from the screen.

Note
  - A closed display only means the associated window is not visible anymore. This does not mean the display has been destroyed. Use show() to make the associated window reappear.
  - Using close() on a closed display does nothing.

CImgDisplay& move | ( | const int | pos_x,
|  | const int | pos_y
| ) |  |

Move associated window to a new location.

Parameters

  pos_x | X-coordinate of the new window location.
  pos_y | Y-coordinate of the new window location.

Note
  Depending on the window manager behavior, this method may not succeed (no exceptions are thrown nevertheless).

CImgDisplay& resize | ( | const bool | force_redraw = `true` | ) |

Resize display to the size of the associated window.

Parameters

  force_redraw | Tells if the previous window content must be updated and refreshed as well.

Note
  - Calling this method ensures that width() and window_width() become equal, as well as height() and window_height().
  - The associated window is also resized to specified dimensions.

CImgDisplay& resize | ( | const int | width,
|  | const int | height,
|  | const bool | force_redraw = `true`
| ) |  |

Resize display to the specified size.

Parameters

  width | Requested display width.
  height | Requested display height.
  force_redraw | Tells if the previous window content must be updated and refreshed as well.

Note
  The associated window is also resized to specified dimensions.

CImgDisplay& resize | ( | const CImg< T > & | img,
|  | const bool | force_redraw = `true`
| ) |  |

Resize display to the size of an input image.

Parameters

  img | Input image to take size from.
  force_redraw | Tells if the previous window content must be resized and updated as well.

Note
  - Calling this method ensures that width() and `img.width()` become equal, as well as height() and `img.height()`.
  - The associated window is also resized to specified dimensions.

CImgDisplay& resize | ( | const CImgDisplay & | disp,
|  | const bool | force_redraw = `true`
| ) |  |

Resize display to the size of another CImgDisplay instance.

Parameters

  disp | Input display to take size from.
  force_redraw | Tells if the previous window content must be resized and updated as well.

Note
  - Calling this method ensures that width() and `disp.width()` become equal, as well as height() and `disp.height()`.
  - The associated window is also resized to specified dimensions.

CImgDisplay& set_normalization | ( | const unsigned int | normalization | ) |

Set normalization type.

Parameters

  normalization | New normalization mode.

CImgDisplay& set_title | ( | const char *const | format,
|  |  | ...
| ) |  |

Set title of the associated window.

Parameters

  format | C-string containing the format of the title, as with `std::printf()`.

Warning
  As the first argument is a format string, it is highly recommended to write
  disp.set_title("%s",window_title);
  instead of
  disp.set_title(window_title);
  if `window_title` can be arbitrary, to prevent nasty memory access.

CImgDisplay& set_fullscreen | ( | const bool | is_fullscreen,
|  | const bool | force_redraw = `true`
| ) |  |

Enable or disable fullscreen mode.

Parameters

  is_fullscreen | Tells is the fullscreen mode must be activated or not.
  force_redraw | Tells if the previous window content must be displayed as well.

Note
  - When the fullscreen mode is enabled, the associated window fills the entire screen but the size of the current display is not modified.
  - The screen resolution may be switched to fit the associated window size and ensure it appears the largest as possible. For X-Window (X11) users, the configuration flag `cimg_use_xrandr` has to be set to allow the screen resolution change (requires the X11 extensions to be enabled).

CImgDisplay& toggle_fullscreen | ( | const bool | force_redraw = `true` | ) |

Toggle fullscreen mode.

Parameters

  force_redraw | Tells if the previous window content must be displayed as well.

Note
  Enable fullscreen mode if it was not enabled, and disable it otherwise.

CImgDisplay& show_mouse | ( |  | ) |

Show mouse pointer.

Note
  Depending on the window manager behavior, this method may not succeed (no exceptions are thrown nevertheless).

CImgDisplay& hide_mouse | ( |  | ) |

Hide mouse pointer.

Note
  Depending on the window manager behavior, this method may not succeed (no exceptions are thrown nevertheless).

CImgDisplay& set_mouse | ( | const int | pos_x,
|  | const int | pos_y
| ) |  |

Move mouse pointer to a specified location.

Note
  Depending on the window manager behavior, this method may not succeed (no exceptions are thrown nevertheless).

CImgDisplay& set_button | ( |  | ) |

Simulate a mouse button release event.

Note
  All mouse buttons are considered released at the same time.

CImgDisplay& set_button | ( | const unsigned int | button,
|  | const bool | is_pressed = `true`
| ) |  |

Simulate a mouse button press or release event.

Parameters

  button | Buttons event code, where each button is associated to a single bit.
  is_pressed | Tells if the mouse button is considered as pressed or released.

CImgDisplay& set_wheel | ( |  | ) |

Flush all mouse wheel events.

Note
  Make wheel() to return `0`, if called afterwards.

CImgDisplay& set_wheel | ( | const int | amplitude | ) |

Simulate a wheel event.

Parameters

  amplitude | Amplitude of the wheel scrolling to simulate.

Note
  Make wheel() to return `amplitude`, if called afterwards.

CImgDisplay& set_key | ( |  | ) |

Flush all key events.

Note
  Make key() to return `0`, if called afterwards.

CImgDisplay& set_key | ( | const unsigned int | keycode,
|  | const bool | is_pressed = `true`
| ) |  |

Simulate a keyboard press/release event.

Parameters

  keycode | Keycode of the associated key.
  is_pressed | Tells if the key is considered as pressed or released.

Note
  Keycode constants are defined in the cimg namespace and are architecture-dependent. Use them to ensure your code stay portable (see cimg::keyESC).

CImgDisplay& flush | ( |  | ) |

Flush all display events.

Note
  Remove all passed events from the current display.

CImgDisplay& wait | ( | const unsigned int | milliseconds | ) |

Wait for a given number of milliseconds since the last call to wait().

Parameters

  milliseconds | Number of milliseconds to wait for.

Note
  Similar to cimg::wait().

CImgDisplay& render | ( | const CImg< T > & | img | ) |

Render image into internal display buffer.

Parameters

  img | Input image data to render.

Note
  - Convert image data representation into the internal display buffer (architecture-dependent structure).
  - The content of the associated window is not modified, until paint() is called.
  - Should not be used for common CImgDisplay uses, since display() is more useful.

CImgDisplay& paint | ( |  | ) |

Paint internal display buffer on associated window.

Note
  - Update the content of the associated window with the internal display buffer, e.g. after a render() call.
  - Should not be used for common CImgDisplay uses, since display() is more useful.

const CImgDisplay& snapshot | ( | CImg< T > & | img | ) | const

Take a snapshot of the associated window content.

Parameters

  [out] | img | Output snapshot. Can be empty on input.