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Backends: Emscripten: Standardise internal helper naming and linkage

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This commit is contained in:
SlowRiot 2026-09-03 14:14:37 +01:00
parent 9fc439dd6f
commit 10a5ecc6af
1 changed files with 53 additions and 74 deletions
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127
backends/imgui_impl_emscripten.cpp
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@ -26,14 +26,10 @@ extern ImGuiID ImHashStr(char const* data, size_t data_size = 0, ImGuiID seed =
float ImGui_ImplEmscripten_TargetDevicePixelRatio = 1.0f;
namespace {
// W3C UI Events KeyboardEvent.code translation helpers
ImGuiKey translate_key(char const* emscripten_key);
constexpr ImGuiMouseButton translate_mousebutton(unsigned short emscripten_button) __attribute__((__const__));
} // anonymous namespace
static ImGuiKey ImGui_ImplEmscripten_TranslateKey(char const* emscripten_key);
static constexpr ImGuiMouseButton ImGui_ImplEmscripten_TranslateMouseButton(unsigned short emscripten_button) __attribute__((__const__));
namespace emscripten_browser_cursor_internal
{
@ -94,13 +90,11 @@ enum class cursor
invalid
};
void set(cursor new_cursor); // set a new cursor from a cursor enum
char* get_string(); // read the current cursor setting as an owned string, caller must free()
void set(char const* new_cursor); // set the cursor from an arbitrary string
} // namespace emscripten_browser_cursor_internal
namespace {
static void ImGui_ImplEmscripten_SetBrowserCursor(emscripten_browser_cursor_internal::cursor new_cursor); // set a new cursor from a cursor enum
static char* ImGui_ImplEmscripten_GetBrowserCursor(); // read the current cursor setting as an owned string, caller must free()
static void ImGui_ImplEmscripten_SetBrowserCursor(char const* new_cursor); // set the cursor from an arbitrary string
struct ImGui_ImplEmscripten_Data
{
@ -111,15 +105,15 @@ struct ImGui_ImplEmscripten_Data
bool LastNoMouseCursorChange = false;
};
float get_target_device_pixel_ratio()
static float ImGui_ImplEmscripten_GetTargetDevicePixelRatio()
{
IM_ASSERT(ImGui_ImplEmscripten_TargetDevicePixelRatio > 0.0f && "ImGui_ImplEmscripten_TargetDevicePixelRatio must be positive.");
return ImGui_ImplEmscripten_TargetDevicePixelRatio > 0.0f ? ImGui_ImplEmscripten_TargetDevicePixelRatio : 1.0f;
}
void update_display_properties(ImGuiIO& io, ImGui_ImplEmscripten_Data* bd, float css_width, float css_height)
static void ImGui_ImplEmscripten_UpdateDisplayProperties(ImGuiIO& io, ImGui_ImplEmscripten_Data* bd, float css_width, float css_height)
{
float const target_device_pixel_ratio = get_target_device_pixel_ratio();
float const target_device_pixel_ratio = ImGui_ImplEmscripten_GetTargetDevicePixelRatio();
float const css_to_imgui_scale = (float)emscripten_get_device_pixel_ratio() / target_device_pixel_ratio;
bd->CssToImGuiScale = css_to_imgui_scale;
io.DisplaySize.x = css_width * css_to_imgui_scale;
@ -128,13 +122,11 @@ void update_display_properties(ImGuiIO& io, ImGui_ImplEmscripten_Data* bd, float
}
// Backend data stored in io.BackendPlatformUserData to allow support for multiple Dear ImGui contexts
ImGui_ImplEmscripten_Data* ImGui_ImplEmscripten_GetBackendData()
static ImGui_ImplEmscripten_Data* ImGui_ImplEmscripten_GetBackendData()
{
return ImGui::GetCurrentContext() ? (ImGui_ImplEmscripten_Data*)ImGui::GetIO().BackendPlatformUserData : nullptr;
}
} // anonymous namespace
void ImGui_ImplEmscripten_Init()
{
// Initialise the Emscripten backend, setting input callbacks
@ -147,7 +139,7 @@ void ImGui_ImplEmscripten_Init()
io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;
// set up initial display size values
update_display_properties(
ImGui_ImplEmscripten_UpdateDisplayProperties(
io,
bd,
(float)EM_ASM_INT(return window.innerWidth;),
@ -173,7 +165,7 @@ void ImGui_ImplEmscripten_Init()
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
ImGui::GetIO().AddMouseButtonEvent(ImGui_ImplEmscripten_TranslateMouseButton(mouse_event->button), true); // translated button, down
return true; // the event was consumed
}
);
@ -182,7 +174,7 @@ void ImGui_ImplEmscripten_Init()
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
ImGui::GetIO().AddMouseButtonEvent(ImGui_ImplEmscripten_TranslateMouseButton(mouse_event->button), false); // translated button, up
return true; // the event was consumed
}
);
@ -243,7 +235,7 @@ void ImGui_ImplEmscripten_Init()
nullptr, // userData
false, // useCapture
[](int /*event_type*/, EmscriptenKeyboardEvent const* key_event, void* /*data*/) { // callback, event_type == EMSCRIPTEN_EVENT_KEYDOWN
const ImGuiKey key = translate_key(key_event->code);
const ImGuiKey key = ImGui_ImplEmscripten_TranslateKey(key_event->code);
ImGuiIO& io = ImGui::GetIO();
io.AddKeyEvent(key, true);
switch (key) // special cases for certain key events
@ -281,7 +273,7 @@ void ImGui_ImplEmscripten_Init()
nullptr, // userData
false, // useCapture
[](int /*event_type*/, EmscriptenKeyboardEvent const* key_event, void* /*data*/) { // callback, event_type == EMSCRIPTEN_EVENT_KEYUP
const ImGuiKey key = translate_key(key_event->code);
const ImGuiKey key = ImGui_ImplEmscripten_TranslateKey(key_event->code);
ImGuiIO& io = ImGui::GetIO();
io.AddKeyEvent(key, false);
switch (key) // special cases for certain key events
@ -325,7 +317,7 @@ void ImGui_ImplEmscripten_Init()
[](int /*event_type*/, EmscriptenUiEvent const* event, void* /*data*/) { // event_type == EMSCRIPTEN_EVENT_RESIZE
ImGuiIO& io = ImGui::GetIO();
ImGui_ImplEmscripten_Data* bd = ImGui_ImplEmscripten_GetBackendData();
if (bd != nullptr) update_display_properties(io, bd, (float)event->windowInnerWidth, (float)event->windowInnerHeight);
if (bd != nullptr) ImGui_ImplEmscripten_UpdateDisplayProperties(io, bd, (float)event->windowInnerWidth, (float)event->windowInnerHeight);
return true; // the event was consumed
}
);
@ -401,7 +393,7 @@ void ImGui_ImplEmscripten_Shutdown()
if (bd->CursorToRestore != nullptr)
{
emscripten_browser_cursor_internal::set(bd->CursorToRestore); // restore the previous cursor state if imgui still owns the cursor on shutdown
ImGui_ImplEmscripten_SetBrowserCursor(bd->CursorToRestore); // restore the previous cursor state if imgui still owns the cursor on shutdown
free(bd->CursorToRestore);
}
@ -412,26 +404,24 @@ void ImGui_ImplEmscripten_Shutdown()
IM_DELETE(bd);
}
namespace {
void restore_cursor_if_necessary(ImGui_ImplEmscripten_Data* bd)
static void ImGui_ImplEmscripten_RestoreMouseCursor(ImGui_ImplEmscripten_Data* bd)
{
if (bd->CursorToRestore == nullptr) return;
emscripten_browser_cursor_internal::set(bd->CursorToRestore); // restore the previous cursor state when leaving imgui cursor ownership
ImGui_ImplEmscripten_SetBrowserCursor(bd->CursorToRestore); // restore the previous cursor state when leaving imgui cursor ownership
free(bd->CursorToRestore);
bd->CursorToRestore = nullptr;
bd->CurrentCursor = emscripten_browser_cursor_internal::cursor::invalid; // select an unused value for current cursor to force a set next time
}
void set_cursor_if_necessary(ImGui_ImplEmscripten_Data* bd, emscripten_browser_cursor_internal::cursor new_cursor)
static void ImGui_ImplEmscripten_SetMouseCursor(ImGui_ImplEmscripten_Data* bd, emscripten_browser_cursor_internal::cursor new_cursor)
{
if (new_cursor == bd->CurrentCursor) return; // don't do anything if the current cursor is already set
if (bd->CursorToRestore == nullptr) bd->CursorToRestore = emscripten_browser_cursor_internal::get_string(); // back up the existing cursor state when first taking cursor ownership
if (bd->CursorToRestore == nullptr) bd->CursorToRestore = ImGui_ImplEmscripten_GetBrowserCursor(); // back up the existing cursor state when first taking cursor ownership
bd->CurrentCursor = new_cursor;
emscripten_browser_cursor_internal::set(new_cursor);
ImGui_ImplEmscripten_SetBrowserCursor(new_cursor);
}
void update_cursor(ImGui_ImplEmscripten_Data* bd)
static void ImGui_ImplEmscripten_UpdateMouseCursor(ImGui_ImplEmscripten_Data* bd)
{
// Sync any cursor changes due to ImGui to the browser's cursor
ImGuiIO& io = ImGui::GetIO();
@ -453,14 +443,14 @@ void update_cursor(ImGui_ImplEmscripten_Data* bd)
{
if (bd->LastMouseDrawCursor) return;
set_cursor_if_necessary(bd, emscripten_browser_cursor_internal::cursor::none); // hide the cursor for the entire window if imgui is handling cursor drawing - not just when imgui wants to capture the mouse
ImGui_ImplEmscripten_SetMouseCursor(bd, emscripten_browser_cursor_internal::cursor::none); // hide the cursor for the entire window if imgui is handling cursor drawing - not just when imgui wants to capture the mouse
bd->LastMouseDrawCursor = true;
}
else
{
if (bd->LastMouseDrawCursor)
{
restore_cursor_if_necessary(bd);
ImGui_ImplEmscripten_RestoreMouseCursor(bd);
bd->LastMouseDrawCursor = false;
}
}
@ -470,58 +460,53 @@ void update_cursor(ImGui_ImplEmscripten_Data* bd)
switch (ImGui::GetMouseCursor())
{
case ImGuiMouseCursor_None:
set_cursor_if_necessary(bd, emscripten_browser_cursor_internal::cursor::none);
ImGui_ImplEmscripten_SetMouseCursor(bd, emscripten_browser_cursor_internal::cursor::none);
break;
case ImGuiMouseCursor_Arrow:
set_cursor_if_necessary(bd, emscripten_browser_cursor_internal::cursor::cursor_default);
ImGui_ImplEmscripten_SetMouseCursor(bd, emscripten_browser_cursor_internal::cursor::cursor_default);
break;
case ImGuiMouseCursor_TextInput: // When hovering over InputText, etc.
set_cursor_if_necessary(bd, emscripten_browser_cursor_internal::cursor::text);
ImGui_ImplEmscripten_SetMouseCursor(bd, emscripten_browser_cursor_internal::cursor::text);
break;
case ImGuiMouseCursor_ResizeAll: // (Unused by Dear ImGui functions)
set_cursor_if_necessary(bd, emscripten_browser_cursor_internal::cursor::move);
ImGui_ImplEmscripten_SetMouseCursor(bd, emscripten_browser_cursor_internal::cursor::move);
break;
case ImGuiMouseCursor_ResizeNS: // When hovering over a horizontal border
set_cursor_if_necessary(bd, emscripten_browser_cursor_internal::cursor::ns_resize);
ImGui_ImplEmscripten_SetMouseCursor(bd, emscripten_browser_cursor_internal::cursor::ns_resize);
break;
case ImGuiMouseCursor_ResizeEW: // When hovering over a vertical border or a column
set_cursor_if_necessary(bd, emscripten_browser_cursor_internal::cursor::ew_resize);
ImGui_ImplEmscripten_SetMouseCursor(bd, 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(bd, emscripten_browser_cursor_internal::cursor::nesw_resize);
ImGui_ImplEmscripten_SetMouseCursor(bd, 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(bd, emscripten_browser_cursor_internal::cursor::nwse_resize);
ImGui_ImplEmscripten_SetMouseCursor(bd, 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(bd, emscripten_browser_cursor_internal::cursor::pointer);
ImGui_ImplEmscripten_SetMouseCursor(bd, emscripten_browser_cursor_internal::cursor::pointer);
break;
case ImGuiMouseCursor_NotAllowed: // When hovering something with disallowed interaction. Usually a crossed circle.
set_cursor_if_necessary(bd, emscripten_browser_cursor_internal::cursor::not_allowed);
ImGui_ImplEmscripten_SetMouseCursor(bd, emscripten_browser_cursor_internal::cursor::not_allowed);
break;
}
}
else // mouse is away from the gui, hovering over some other part of the viewport
{
restore_cursor_if_necessary(bd);
ImGui_ImplEmscripten_RestoreMouseCursor(bd);
}
}
} // anonymous namespace
void ImGui_ImplEmscripten_NewFrame()
{
ImGui_ImplEmscripten_Data* bd = ImGui_ImplEmscripten_GetBackendData();
IM_ASSERT(bd != nullptr && "Context or backend not initialized? Did you call ImGui_ImplEmscripten_Init()?");
// Update any state that needs to be polled
update_cursor(bd);
ImGui_ImplEmscripten_UpdateMouseCursor(bd);
}
namespace emscripten_browser_cursor_internal
{
char* get_string()
static char* ImGui_ImplEmscripten_GetBrowserCursor()
{
// Return the current cursor setting as a newly-allocated string, caller must free it.
return (char*)EM_ASM_PTR(
@ -529,47 +514,47 @@ char* get_string()
);
}
void set(cursor new_cursor)
static void ImGui_ImplEmscripten_SetBrowserCursor(emscripten_browser_cursor_internal::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::none:
case emscripten_browser_cursor_internal::cursor::none:
EM_ASM(document.body.style.cursor = 'none';);
break;
case cursor::cursor_default:
case emscripten_browser_cursor_internal::cursor::cursor_default:
default:
EM_ASM(document.body.style.cursor = 'default';);
break;
case cursor::pointer:
case emscripten_browser_cursor_internal::cursor::pointer:
EM_ASM(document.body.style.cursor = 'pointer';);
break;
case cursor::text:
case emscripten_browser_cursor_internal::cursor::text:
EM_ASM(document.body.style.cursor = 'text';);
break;
case cursor::move:
case emscripten_browser_cursor_internal::cursor::move:
EM_ASM(document.body.style.cursor = 'move';);
break;
case cursor::not_allowed:
case emscripten_browser_cursor_internal::cursor::not_allowed:
EM_ASM(document.body.style.cursor = 'not-allowed';);
break;
case cursor::ew_resize:
case emscripten_browser_cursor_internal::cursor::ew_resize:
EM_ASM(document.body.style.cursor = 'ew-resize';);
break;
case cursor::ns_resize:
case emscripten_browser_cursor_internal::cursor::ns_resize:
EM_ASM(document.body.style.cursor = 'ns-resize';);
break;
case cursor::nesw_resize:
case emscripten_browser_cursor_internal::cursor::nesw_resize:
EM_ASM(document.body.style.cursor = 'nesw-resize';);
break;
case cursor::nwse_resize:
case emscripten_browser_cursor_internal::cursor::nwse_resize:
EM_ASM(document.body.style.cursor = 'nwse-resize';);
break;
}
}
void set(char const* new_cursor)
static void ImGui_ImplEmscripten_SetBrowserCursor(char const* new_cursor)
{
// Set the cursor from an arbitrary string
EM_ASM({
@ -577,11 +562,7 @@ void set(char const* new_cursor)
}, new_cursor);
}
} // namespace emscripten_browser_cursor_internal
namespace {
constexpr ImGuiMouseButton translate_mousebutton(unsigned short emscripten_button)
static constexpr ImGuiMouseButton ImGui_ImplEmscripten_TranslateMouseButton(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
@ -590,7 +571,7 @@ constexpr ImGuiMouseButton translate_mousebutton(unsigned short emscripten_butto
return emscripten_button; // any other button translates 1:1
}
ImGuiStorage const& get_key_translation_storage()
static ImGuiStorage const& ImGui_ImplEmscripten_GetKeyTranslationStorage()
{
static ImGuiStorage storage;
static bool is_initialized = false;
@ -805,15 +786,13 @@ ImGuiStorage const& get_key_translation_storage()
return storage;
}
ImGuiKey translate_key(char const* emscripten_key)
static ImGuiKey ImGui_ImplEmscripten_TranslateKey(char const* emscripten_key)
{
// Translate a W3C KeyboardEvent.code string into an ImGuiKey.
if (emscripten_key == nullptr || emscripten_key[0] == '\0') return ImGuiKey_None;
ImGuiStorage const& storage = get_key_translation_storage();
ImGuiStorage const& storage = ImGui_ImplEmscripten_GetKeyTranslationStorage();
return (ImGuiKey)storage.GetInt(ImHashStr(emscripten_key), ImGuiKey_None);
}
} // anonymous namespace
#endif // IMGUI_DISABLE