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imgui/backends/imgui_impl_emscripten.cpp

610 lines
35 KiB
C++

// dear imgui: Platform Backend for Emscripten HTML5
//
// See documentation in imgui_impl_emscripten.h.
//
// Copyright 2024 Eugene Hopkinson
#include "imgui.h"
#ifndef IMGUI_DISABLE
#include "imgui_impl_emscripten.h"
#include <emscripten.h>
#include <emscripten/html5.h>
#include <emscripten/val.h>
namespace {
/// A map of HTML5 key names to imgui keys
static const std::unordered_map<std::string, ImGuiKey> key_translate_lookup{
// main character keys
{"Backquote", ImGuiKey_GraveAccent},
{"Backslash", ImGuiKey_Backslash},
{"BracketLeft", ImGuiKey_LeftBracket},
{"BracketRight", ImGuiKey_RightBracket},
{"Comma", ImGuiKey_Comma},
{"Digit0", ImGuiKey_0},
{"Digit1", ImGuiKey_1},
{"Digit2", ImGuiKey_2},
{"Digit3", ImGuiKey_3},
{"Digit4", ImGuiKey_4},
{"Digit5", ImGuiKey_5},
{"Digit6", ImGuiKey_6},
{"Digit7", ImGuiKey_7},
{"Digit8", ImGuiKey_8},
{"Digit9", ImGuiKey_9},
{"Equal", ImGuiKey_Equal},
{"IntlBackslash", ImGuiKey_Backslash}, // Mapping to generic backslash
{"IntlRo", ImGuiKey_Slash}, // Closest match for non-standard layouts
{"IntlYen", ImGuiKey_Backslash}, // Closest match for non-standard layouts
{"KeyA", ImGuiKey_A},
{"KeyB", ImGuiKey_B},
{"KeyC", ImGuiKey_C},
{"KeyD", ImGuiKey_D},
{"KeyE", ImGuiKey_E},
{"KeyF", ImGuiKey_F},
{"KeyG", ImGuiKey_G},
{"KeyH", ImGuiKey_H},
{"KeyI", ImGuiKey_I},
{"KeyJ", ImGuiKey_J},
{"KeyK", ImGuiKey_K},
{"KeyL", ImGuiKey_L},
{"KeyM", ImGuiKey_M},
{"KeyN", ImGuiKey_N},
{"KeyO", ImGuiKey_O},
{"KeyP", ImGuiKey_P},
{"KeyQ", ImGuiKey_Q},
{"KeyR", ImGuiKey_R},
{"KeyS", ImGuiKey_S},
{"KeyT", ImGuiKey_T},
{"KeyU", ImGuiKey_U},
{"KeyV", ImGuiKey_V},
{"KeyW", ImGuiKey_W},
{"KeyX", ImGuiKey_X},
{"KeyY", ImGuiKey_Y},
{"KeyZ", ImGuiKey_Z},
{"Minus", ImGuiKey_Minus},
{"Period", ImGuiKey_Period},
{"Quote", ImGuiKey_Apostrophe},
{"Semicolon", ImGuiKey_Semicolon},
{"Slash", ImGuiKey_Slash},
// control keys
{"AltLeft", ImGuiKey_LeftAlt},
{"AltRight", ImGuiKey_RightAlt},
{"Backspace", ImGuiKey_Backspace},
{"CapsLock", ImGuiKey_CapsLock},
{"ContextMenu", ImGuiKey_Menu},
{"ControlLeft", ImGuiKey_LeftCtrl},
{"ControlRight", ImGuiKey_RightCtrl},
{"Enter", ImGuiKey_Enter},
{"MetaLeft", ImGuiKey_LeftSuper},
{"MetaRight", ImGuiKey_RightSuper},
{"ShiftLeft", ImGuiKey_LeftShift},
{"ShiftRight", ImGuiKey_RightShift},
{"Space", ImGuiKey_Space},
{"Tab", ImGuiKey_Tab},
// navigation key group
{"Delete", ImGuiKey_Delete},
{"End", ImGuiKey_End},
//{"Help", ImGuiKey_PrintScreen}, // Best approximation
{"Home", ImGuiKey_Home},
{"Insert", ImGuiKey_Insert},
{"PageDown", ImGuiKey_PageDown},
{"PageUp", ImGuiKey_PageUp},
// arrow key group
{"ArrowDown", ImGuiKey_DownArrow},
{"ArrowLeft", ImGuiKey_LeftArrow},
{"ArrowRight", ImGuiKey_RightArrow},
{"ArrowUp", ImGuiKey_UpArrow},
// number pad group
{"NumLock", ImGuiKey_NumLock},
{"Numpad0", ImGuiKey_Keypad0},
{"Numpad1", ImGuiKey_Keypad1},
{"Numpad2", ImGuiKey_Keypad2},
{"Numpad3", ImGuiKey_Keypad3},
{"Numpad4", ImGuiKey_Keypad4},
{"Numpad5", ImGuiKey_Keypad5},
{"Numpad6", ImGuiKey_Keypad6},
{"Numpad7", ImGuiKey_Keypad7},
{"Numpad8", ImGuiKey_Keypad8},
{"Numpad9", ImGuiKey_Keypad9},
{"NumpadAdd", ImGuiKey_KeypadAdd},
{"NumpadBackspace", ImGuiKey_Backspace}, // No direct mapping; backspace functionality
//{"NumpadClear", ImGuiKey_KeypadClear}, // Custom-defined if needed
//{"NumpadClearEntry", ImGuiKey_KeypadClear}, // Custom-defined if needed
{"NumpadComma", ImGuiKey_KeypadDecimal}, // Closest match
{"NumpadDecimal", ImGuiKey_KeypadDecimal},
{"NumpadDivide", ImGuiKey_KeypadDivide},
{"NumpadEnter", ImGuiKey_KeypadEnter},
{"NumpadEqual", ImGuiKey_KeypadEqual},
{"NumpadHash", ImGuiKey_Backslash}, // Mapped to # on UK keyboard
//{"NumpadMemoryAdd", ImGuiKey_None}, // No defined mapping
//{"NumpadMemoryClear", ImGuiKey_None}, // No defined mapping
//{"NumpadMemoryRecall", ImGuiKey_None}, // No defined mapping
//{"NumpadMemoryStore", ImGuiKey_None}, // No defined mapping
//{"NumpadMemorySubtract", ImGuiKey_None}, // No defined mapping
{"NumpadMultiply", ImGuiKey_KeypadMultiply},
{"NumpadParenLeft", ImGuiKey_LeftBracket}, // Closest available
{"NumpadParenRight", ImGuiKey_RightBracket}, // Closest available
{"NumpadStar", ImGuiKey_KeypadMultiply}, // Same as multiply
{"NumpadSubtract", ImGuiKey_KeypadSubtract},
// top row key groups
{"Escape", ImGuiKey_Escape},
{"F1", ImGuiKey_F1},
{"F2", ImGuiKey_F2},
{"F3", ImGuiKey_F3},
{"F4", ImGuiKey_F4},
{"F5", ImGuiKey_F5},
{"F6", ImGuiKey_F6},
{"F6", ImGuiKey_F6},
{"F7", ImGuiKey_F7},
{"F8", ImGuiKey_F8},
{"F9", ImGuiKey_F9},
{"F10", ImGuiKey_F10},
{"F11", ImGuiKey_F11},
{"F12", ImGuiKey_F12},
//{"Fn", ImGuiKey_None}, // No direct mapping
//{"FnLock", ImGuiKey_None}, // No direct mapping
{"PrintScreen", ImGuiKey_PrintScreen},
{"ScrollLock", ImGuiKey_ScrollLock},
{"Pause", ImGuiKey_Pause},
};
ImGuiKey translate_key(char const* emscripten_key) __attribute__((__const__));
ImGuiKey translate_key(char const* emscripten_key) {
/// Translate an emscripten-provided browser string describing a keycode to an imgui key code
if(auto it{key_translate_lookup.find(emscripten_key)}; it != key_translate_lookup.end()) {
return it->second;
}
return ImGuiKey_None;
}
constexpr ImGuiMouseButton translate_mousebutton(unsigned short emscripten_button) __attribute__((__const__));
constexpr ImGuiMouseButton translate_mousebutton(unsigned short emscripten_button) {
/// Translate an emscripten-provided integer describing a mouse button to an imgui mouse button
if(emscripten_button == 1) return ImGuiMouseButton_Middle; // 1 = middle mouse button
if(emscripten_button == 2) return ImGuiMouseButton_Right; // 2 = right mouse button
if(emscripten_button > ImGuiMouseButton_COUNT) return ImGuiMouseButton_Middle; // treat any weird clicks on unexpected buttons (button 6 upwards) as middle mouse
return emscripten_button; // any other button translates 1:1
}
} // anonymous namespace
namespace emscripten_browser_cursor_internal {
////////////////////////////////// Interface ///////////////////////////////////
enum class cursor {
// General
cursor_auto, // The UA will determine the cursor to display based on the current context. E.g., equivalent to text when hovering text.
cursor_default, // The platform-dependent default cursor. Typically an arrow.
none, // No cursor is rendered.
// Links & status
context_menu, // cursor slightly obscuring a menu icon - A context menu is available.
help, // cursor next to a question mark - Help information is available.
pointer, // right hand with an index finger pointing up - The cursor is a pointer that indicates a link. Typically an image of a pointing hand.
progress, // cursor and hour glass - The program is busy in the background, but the user can still interact with the interface (in contrast to wait).
wait, // hour glass - The program is busy, and the user can't interact with the interface (in contrast to progress). Sometimes an image of an hourglass or a watch.
// Selection
cell, // plus symbol - The table cell or set of cells can be selected.
crosshair, // crosshair - Cross cursor, often used to indicate selection in a bitmap.
text, // vertical i-beam - The text can be selected. Typically the shape of an I-beam.
vertical_text, // horizontal i-beam - The vertical text can be selected. Typically the shape of a sideways I-beam.
// Drag & drop
alias, // cursor next to a folder icon with a curved arrow pointing up and to the right - An alias or shortcut is to be created.
copy, // cursor next to a smaller folder icon with a plus sign - Something is to be copied.
move, // plus sign made of two thin lines, with small arrows facing out - Something is to be moved.
no_drop, // cursor next to circle with a line through it - An item may not be dropped at the current location.
not_allowed, // Circle with a line through it - The requested action will not be carried out.
grab, // fully opened hand - Something can be grabbed (dragged to be moved).
grabbing, // closed hand - Something is being grabbed (dragged to be moved).
// Resizing & scrolling
all_scroll, // dot with four triangles around it - Something can be scrolled in any direction (panned).
col_resize, // The item/column can be resized horizontally. Often rendered as arrows pointing left and right with a vertical bar separating them.
row_resize, // The item/row can be resized vertically. Often rendered as arrows pointing up and down with a horizontal bar separating them.
n_resize, // arrow pointing up - Some edge is to be moved. For example, the se-resize cursor is used when the movement starts from the south-east corner of the box.
e_resize, // arrow pointing right
s_resize, // arrow pointing down
w_resize, // arrow pointing left
ne_resize, // arrow pointing top-right
nw_resize, // arrow pointing top-left
se_resize, // arrow pointing bottom-right
sw_resize, // arrow pointing bottom-left
ew_resize, // arrow pointing left and right - Bidirectional resize cursor.
ns_resize, // arrow pointing up and down
nesw_resize, // arrow pointing both to the top-right and bottom-left
nwse_resize, // arrow pointing both to the top-left and bottom-right
// Zooming
zoom_in, // magnifying glass with a plus sign - Something can be zoomed (magnified) in or out.
zoom_out,
// Special invalid value
invalid = std::numeric_limits<int>::max()
};
void set(cursor new_cursor); // set a new cursor from a cursor enum
void unset(); // clear the current cursor setting
//////////////////////////////// Implementation ////////////////////////////////
bool is_set() {
/// Returns whether the cursor is currently set
return EM_ASM_INT(
return !(!document.body.style.cursor || document.body.style.cursor.length === 0 );
);
}
std::string get_string() {
/// Return the current cursor setting as a string
auto cursor_str_ptr{reinterpret_cast<char*>(EM_ASM_PTR(
return stringToNewUTF8(document.body.style.cursor);
))};
std::string const cursor_str{cursor_str_ptr};
free(cursor_str_ptr);
return cursor_str;
}
void set(cursor new_cursor) {
/// Set the cursor according to the given enum
// Note, implementations omitted for cursors not used by imgui. For full implementation, use https://github.com/Armchair-Software/emscripten-browser-cursor
switch(new_cursor) {
case cursor::cursor_default:
default:
EM_ASM(document.body.style.cursor = 'default';);
break;
case cursor::pointer:
EM_ASM(document.body.style.cursor = 'pointer';);
break;
case cursor::text:
EM_ASM(document.body.style.cursor = 'text';);
break;
case cursor::move:
EM_ASM(document.body.style.cursor = 'move';);
break;
case cursor::not_allowed:
EM_ASM(document.body.style.cursor = 'not-allowed';);
break;
case cursor::ew_resize:
EM_ASM(document.body.style.cursor = 'ew-resize';);
break;
case cursor::ns_resize:
EM_ASM(document.body.style.cursor = 'ns-resize';);
break;
case cursor::nesw_resize:
EM_ASM(document.body.style.cursor = 'nesw-resize';);
break;
case cursor::nwse_resize:
EM_ASM(document.body.style.cursor = 'nwse-resize';);
break;
}
}
void set(std::string const &new_cursor) {
/// Set the cursor from an arbitrary string
EM_ASM({
document.body.style.cursor = UTF8ToString($0);
}, new_cursor.c_str());
}
} // namespace emscripten_browser_cursor
namespace {
void update_cursor() {
/// Sync any cursor changes due to ImGUI to the browser's cursor
static emscripten_browser_cursor_internal::cursor current_cursor{emscripten_browser_cursor_internal::cursor::invalid};
static std::optional<std::string> cursor_to_restore;
auto set_cursor_if_necessary{[&](emscripten_browser_cursor_internal::cursor new_cursor){
if(new_cursor == current_cursor) return; // don't do anything if the current cursor is already set
current_cursor = new_cursor;
emscripten_browser_cursor_internal::set(new_cursor);
}};
if(ImGui::GetIO().WantCaptureMouse) { // mouse is hovering over the gui
if(!cursor_to_restore && emscripten_browser_cursor_internal::is_set()) {
cursor_to_restore = emscripten_browser_cursor_internal::get_string(); // back up the existing cursor when entering the imgui capture space
}
switch(ImGui::GetMouseCursor()) {
case ImGuiMouseCursor_Arrow:
set_cursor_if_necessary(emscripten_browser_cursor_internal::cursor::cursor_default);
break;
case ImGuiMouseCursor_TextInput: // When hovering over InputText, etc.
set_cursor_if_necessary(emscripten_browser_cursor_internal::cursor::text);
break;
case ImGuiMouseCursor_ResizeAll: // (Unused by Dear ImGui functions)
set_cursor_if_necessary(emscripten_browser_cursor_internal::cursor::move);
break;
case ImGuiMouseCursor_ResizeNS: // When hovering over a horizontal border
set_cursor_if_necessary(emscripten_browser_cursor_internal::cursor::ns_resize);
break;
case ImGuiMouseCursor_ResizeEW: // When hovering over a vertical border or a column
set_cursor_if_necessary(emscripten_browser_cursor_internal::cursor::ew_resize);
break;
case ImGuiMouseCursor_ResizeNESW: // When hovering over the bottom-left corner of a window
set_cursor_if_necessary(emscripten_browser_cursor_internal::cursor::nesw_resize);
break;
case ImGuiMouseCursor_ResizeNWSE: // When hovering over the bottom-right corner of a window
set_cursor_if_necessary(emscripten_browser_cursor_internal::cursor::nwse_resize);
break;
case ImGuiMouseCursor_Hand: // (Unused by Dear ImGui functions. Use for e.g. hyperlinks)
set_cursor_if_necessary(emscripten_browser_cursor_internal::cursor::pointer);
break;
case ImGuiMouseCursor_NotAllowed: // When hovering something with disallowed interaction. Usually a crossed circle.
set_cursor_if_necessary(emscripten_browser_cursor_internal::cursor::not_allowed);
break;
}
} else { // mouse is away from the gui, hovering over some other part of the viewport
if(cursor_to_restore) {
emscripten_browser_cursor_internal::set(*cursor_to_restore); // restore the previous cursor when leaving the imgui capture space
cursor_to_restore = std::nullopt;
current_cursor = emscripten_browser_cursor_internal::cursor::invalid; // select an unused value for current cursor to force a set next time set_cursor_if_necessary is called
}
}
}
} // anonymous namespace
void ImGui_ImplEmscripten_Init() {
/// Initialise the Emscripten backend, setting input callbacks
auto &imgui_io{ImGui::GetIO()};
imgui_io.BackendPlatformName = "imgui_impl_emscripten";
imgui_io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;
// set up initial display size values
imgui_io.DisplaySize.x = emscripten::val::global("window")["innerWidth"].as<float>();
imgui_io.DisplaySize.y = emscripten::val::global("window")["innerHeight"].as<float>();
emscripten_set_mousemove_callback(
EMSCRIPTEN_EVENT_TARGET_WINDOW, // target
nullptr, // userData
false, // useCapture
[](int /*event_type*/, EmscriptenMouseEvent const *mouse_event, void */*data*/){ // callback, event_type == EMSCRIPTEN_EVENT_MOUSEMOVE
ImGui::GetIO().AddMousePosEvent(
static_cast<float>(mouse_event->clientX),
static_cast<float>(mouse_event->clientY)
);
return true; // the event was consumed
}
);
emscripten_set_mousedown_callback(
EMSCRIPTEN_EVENT_TARGET_WINDOW, // target
nullptr, // userData
false, // useCapture
[](int /*event_type*/, EmscriptenMouseEvent const *mouse_event, void */*data*/){ // callback, event_type == EMSCRIPTEN_EVENT_MOUSEDOWN
ImGui::GetIO().AddMouseButtonEvent(translate_mousebutton(mouse_event->button), true); // translated button, down
return true; // the event was consumed
}
);
emscripten_set_mouseup_callback(
EMSCRIPTEN_EVENT_TARGET_WINDOW, // target
nullptr, // userData
false, // useCapture
[](int /*event_type*/, EmscriptenMouseEvent const *mouse_event, void */*data*/){ // callback, event_type == EMSCRIPTEN_EVENT_MOUSEUP
ImGui::GetIO().AddMouseButtonEvent(translate_mousebutton(mouse_event->button), false); // translated button, up
return true; // the event was consumed
}
);
emscripten_set_mouseenter_callback(
EMSCRIPTEN_EVENT_TARGET_DOCUMENT, // target - WINDOW doesn't produce mouseenter events
nullptr, // userData
false, // useCapture
[](int /*event_type*/, EmscriptenMouseEvent const *mouse_event, void */*data*/){ // callback, event_type == EMSCRIPTEN_EVENT_MOUSEENTER
ImGui::GetIO().AddMousePosEvent(
static_cast<float>(mouse_event->clientX),
static_cast<float>(mouse_event->clientY)
);
return true; // the event was consumed
}
);
emscripten_set_mouseleave_callback(
EMSCRIPTEN_EVENT_TARGET_DOCUMENT, // target - WINDOW doesn't produce mouseenter events
nullptr, // userData
false, // useCapture
[](int /*event_type*/, EmscriptenMouseEvent const */*mouse_event*/, void */*data*/){ // callback, event_type == EMSCRIPTEN_EVENT_MOUSELEAVE
auto &imgui_io{ImGui::GetIO()};
imgui_io.AddMousePosEvent(-FLT_MAX, -FLT_MAX); // cursor is not in the window
imgui_io.ClearInputKeys(); // clear pending input keys on mouse exit
return true; // the event was consumed
}
);
emscripten_set_wheel_callback(
EMSCRIPTEN_EVENT_TARGET_WINDOW, // target
nullptr, // userData
false, // useCapture
[](int /*event_type*/, EmscriptenWheelEvent const *wheel_event, void */*data*/){ // callback, event_type == EMSCRIPTEN_EVENT_WHEEL
float scale{1.0f};
switch(wheel_event->deltaMode) {
case DOM_DELTA_PIXEL: // scrolling in pixels
scale = 1.0f / 100.0f;
break;
case DOM_DELTA_LINE: // scrolling by lines
scale = 1.0f / 3.0f;
break;
case DOM_DELTA_PAGE: // scrolling by pages
scale = 80.0f;
break;
}
// TODO: make scrolling speeds configurable
ImGui::GetIO().AddMouseWheelEvent(
-static_cast<float>(wheel_event->deltaX) * scale,
-static_cast<float>(wheel_event->deltaY) * scale
);
return false; // the event was not consumed
}
);
emscripten_set_keydown_callback(
EMSCRIPTEN_EVENT_TARGET_WINDOW, // target
nullptr, // userData
false, // useCapture
[](int /*event_type*/, EmscriptenKeyboardEvent const *key_event, void */*data*/){ // callback, event_type == EMSCRIPTEN_EVENT_KEYDOWN
auto const key{translate_key(key_event->code)};
auto &imgui_io{ImGui::GetIO()};
imgui_io.AddKeyEvent(key, true);
switch(key) { // special cases for certain key events
case ImGuiKey_LeftCtrl: // additional events for modifier keys
case ImGuiKey_RightCtrl:
imgui_io.AddKeyEvent(ImGuiMod_Ctrl, true);
break;
case ImGuiKey_LeftShift:
case ImGuiKey_RightShift:
imgui_io.AddKeyEvent(ImGuiMod_Shift, true);
break;
case ImGuiKey_LeftAlt:
case ImGuiKey_RightAlt:
imgui_io.AddKeyEvent(ImGuiMod_Alt, true);
break;
case ImGuiKey_LeftSuper:
case ImGuiKey_RightSuper:
imgui_io.AddKeyEvent(ImGuiMod_Super, true);
break;
// TODO: case ImGuiKey_Menu: do we want to do anything with this?
case ImGuiKey_Tab: // consuming tab prevents the user tabbing to other parts of the browser interface outside the window content
return imgui_io.WantCaptureKeyboard; // the event was consumed only if imgui wants to capture the keyboard
case ImGuiKey_Enter: // consuming enter prevents the word "Enter" appearing in text input via the keypress callback
case ImGuiKey_Delete: // consuming enter prevents the word "Delete" appearing in text input via the keypress callback
return imgui_io.WantTextInput; // the event was consumed only if we're currently accepting text input
default:
break;
}
return false; // if no special handling, the event was not consumed
}
);
emscripten_set_keyup_callback(
EMSCRIPTEN_EVENT_TARGET_WINDOW, // target
nullptr, // userData
false, // useCapture
[](int /*event_type*/, EmscriptenKeyboardEvent const *key_event, void */*data*/){ // callback, event_type == EMSCRIPTEN_EVENT_KEYUP
auto const key{translate_key(key_event->code)};
auto &imgui_io{ImGui::GetIO()};
imgui_io.AddKeyEvent(key, false);
switch(key) { // special cases for certain key events
case ImGuiKey_LeftCtrl: // additional events for modifier keys
case ImGuiKey_RightCtrl:
imgui_io.AddKeyEvent(ImGuiMod_Ctrl, false);
break;
case ImGuiKey_LeftShift:
case ImGuiKey_RightShift:
imgui_io.AddKeyEvent(ImGuiMod_Shift, false);
break;
case ImGuiKey_LeftAlt:
case ImGuiKey_RightAlt:
imgui_io.AddKeyEvent(ImGuiMod_Alt, false);
break;
case ImGuiKey_LeftSuper:
case ImGuiKey_RightSuper:
imgui_io.AddKeyEvent(ImGuiMod_Super, false);
break;
default:
break;
}
return false; // the event was not consumed
}
);
emscripten_set_keypress_callback(
EMSCRIPTEN_EVENT_TARGET_WINDOW, // target
nullptr, // userData
false, // useCapture
[](int /*event_type*/, EmscriptenKeyboardEvent const *key_event, void */*data*/){ // callback, event_type == EMSCRIPTEN_EVENT_KEYPRESS
auto &imgui_io{ImGui::GetIO()};
imgui_io.AddInputCharactersUTF8(key_event->key);
return imgui_io.WantCaptureKeyboard; // the event was consumed only if imgui wants to capture the keyboard
}
);
emscripten_set_resize_callback(
EMSCRIPTEN_EVENT_TARGET_WINDOW, // target
nullptr, // userData
false, // useCapture
[](int /*event_type*/, EmscriptenUiEvent const *event, void */*data*/) { // event_type == EMSCRIPTEN_EVENT_RESIZE
auto &imgui_io{ImGui::GetIO()};
imgui_io.DisplaySize.x = static_cast<float>(event->windowInnerWidth);
imgui_io.DisplaySize.y = static_cast<float>(event->windowInnerHeight);
return true; // the event was consumed
}
);
emscripten_set_blur_callback(
EMSCRIPTEN_EVENT_TARGET_WINDOW, // target
nullptr, // userData
false, // useCapture
[](int /*event_type*/, EmscriptenFocusEvent const */*event*/, void */*data*/) { // event_type == EMSCRIPTEN_EVENT_BLUR
auto &imgui_io{ImGui::GetIO()};
imgui_io.AddFocusEvent(false);
imgui_io.ClearInputKeys(); // clear pending input keys on focus gain
return true; // the event was consumed
}
);
emscripten_set_focus_callback(
EMSCRIPTEN_EVENT_TARGET_WINDOW, // target
nullptr, // userData
false, // useCapture
[](int /*event_type*/, EmscriptenFocusEvent const */*event*/, void */*data*/) { // event_type == EMSCRIPTEN_EVENT_FOCUS
auto &imgui_io{ImGui::GetIO()};
imgui_io.AddFocusEvent(true);
imgui_io.ClearInputKeys(); // clear pending input keys on focus loss - for example if you press tab to cycle to another part of the UI
return true; // the event was consumed
}
);
emscripten_set_focusin_callback(
EMSCRIPTEN_EVENT_TARGET_WINDOW, // target
nullptr, // userData
false, // useCapture
[](int /*event_type*/, EmscriptenFocusEvent const */*event*/, void */*data*/) { // event_type == EMSCRIPTEN_EVENT_FOCUSIN
auto &imgui_io{ImGui::GetIO()};
imgui_io.AddFocusEvent(true);
imgui_io.ClearInputKeys(); // clear pending input keys on focus gain
return true; // the event was consumed
}
);
emscripten_set_focusout_callback(
EMSCRIPTEN_EVENT_TARGET_WINDOW, // target
nullptr, // userData
false, // useCapture
[](int /*event_type*/, EmscriptenFocusEvent const */*event*/, void */*data*/) { // event_type == EMSCRIPTEN_EVENT_FOCUSOUT
auto &imgui_io{ImGui::GetIO()};
imgui_io.AddFocusEvent(false);
imgui_io.ClearInputKeys(); // clear pending input keys on focus loss - for example if you press tab to cycle to another part of the UI
return true; // the event was consumed
}
);
// TODO: touch events
}
void ImGui_ImplEmscripten_Shutdown() {
/// Unset any callbacks set by Init
emscripten_set_mousemove_callback( EMSCRIPTEN_EVENT_TARGET_WINDOW, nullptr, false, nullptr);
emscripten_set_mousedown_callback( EMSCRIPTEN_EVENT_TARGET_WINDOW, nullptr, false, nullptr);
emscripten_set_mouseup_callback( EMSCRIPTEN_EVENT_TARGET_WINDOW, nullptr, false, nullptr);
emscripten_set_mouseenter_callback(EMSCRIPTEN_EVENT_TARGET_DOCUMENT, nullptr, false, nullptr);
emscripten_set_mouseleave_callback(EMSCRIPTEN_EVENT_TARGET_DOCUMENT, nullptr, false, nullptr);
emscripten_set_wheel_callback( EMSCRIPTEN_EVENT_TARGET_WINDOW, nullptr, false, nullptr);
emscripten_set_keydown_callback( EMSCRIPTEN_EVENT_TARGET_WINDOW, nullptr, false, nullptr);
emscripten_set_keyup_callback( EMSCRIPTEN_EVENT_TARGET_WINDOW, nullptr, false, nullptr);
emscripten_set_keypress_callback( EMSCRIPTEN_EVENT_TARGET_WINDOW, nullptr, false, nullptr);
emscripten_set_resize_callback( EMSCRIPTEN_EVENT_TARGET_WINDOW, nullptr, false, nullptr);
emscripten_set_focusin_callback( EMSCRIPTEN_EVENT_TARGET_WINDOW, nullptr, false, nullptr);
emscripten_set_focusout_callback( EMSCRIPTEN_EVENT_TARGET_WINDOW, nullptr, false, nullptr);
// TODO: touch events
auto &imgui_io{ImGui::GetIO()};
imgui_io.BackendPlatformName = nullptr;
imgui_io.BackendPlatformUserData = nullptr;
imgui_io.BackendFlags &= ~ImGuiBackendFlags_HasMouseCursors;
}
void ImGui_ImplEmscripten_NewFrame() {
/// Update any state that needs to be polled
update_cursor();
}
#endif // IMGUI_DISABLE