Struct Context 

pub struct Context { /* private fields */ }

An imgui context.

A context needs to be created to access most library functions. Due to current Dear ImGui design choices, at most one active Context can exist at any time. This limitation will likely be removed in a future Dear ImGui version.

If you need more than one context, you can use suspended contexts. As long as only one context is active at a time, it’s possible to have multiple independent contexts.

Examples

Creating a new active context:

let ctx = dear_imgui_rs::Context::create();
// ctx is dropped naturally when it goes out of scope, which deactivates and destroys the
// context

Never try to create an active context when another one is active:

let ctx1 = dear_imgui_rs::Context::create();

let ctx2 = dear_imgui_rs::Context::create(); // PANIC

Implementations

impl Context

pub fn try_create() -> Result<Context, ImGuiError>

Tries to create a new active Dear ImGui context.

Returns an error if another context is already active or creation fails.

pub fn try_create_with_shared_font_atlas( shared_font_atlas: SharedFontAtlas, ) -> Result<Context, ImGuiError>

Tries to create a new active Dear ImGui context with a shared font atlas.

pub fn create() -> Context

Creates a new active Dear ImGui context (panics on error).

This aligns with imgui-rs behavior. For fallible creation use try_create().

pub fn create_with_shared_font_atlas( shared_font_atlas: SharedFontAtlas, ) -> Context

Creates a new active Dear ImGui context with a shared font atlas (panics on error).

pub fn as_raw(&self) -> *mut ImGuiContext

Returns the raw ImGuiContext* for FFI integrations.

pub fn io_mut(&mut self) -> &mut Io

Returns a mutable reference to the active context’s IO object

pub fn io(&self) -> &Io

Get access to the IO structure

pub fn style(&self) -> &Style

Get access to the Style structure

pub fn style_mut(&mut self) -> &mut Style

Get mutable access to the Style structure

pub fn frame(&mut self) -> &mut Ui

Creates a new frame and returns a Ui object for building the interface

pub fn frame_with<F, R>(&mut self, f: F) -> R

where F: FnOnce(&Ui) -> R,

Create a new frame with a callback

pub fn render(&mut self) -> &DrawData

Renders the frame and returns a reference to the resulting draw data

This finalizes the Dear ImGui frame and prepares all draw data for rendering. The returned draw data contains all the information needed to render the frame.

pub fn draw_data(&self) -> Option<&DrawData>

Gets the draw data for the current frame

This returns the draw data without calling render. Only valid after render() has been called and before the next new_frame().

pub fn register_user_texture(&mut self, texture: &mut TextureData)

Register a user-created texture in ImGui’s global texture list (ImGui 1.92+).

Dear ImGui builds DrawData::textures() from its internal PlatformIO.Textures[] list. If you create a TextureData yourself (e.g. OwnedTextureData::new()), you must register it for renderer backends (with BackendFlags::RENDERER_HAS_TEXTURES) to receive Create/Update/Destroy requests automatically.

Note: RegisterUserTexture() is currently an experimental ImGui API.

Safety & Lifetime

The underlying ImTextureData must remain alive and registered until you call unregister_user_texture(). Unregister before dropping the texture to avoid leaving a dangling pointer inside ImGui.

pub fn register_user_texture_token( &mut self, texture: &mut TextureData, ) -> RegisteredUserTexture

Register a user-created texture and return an RAII token which unregisters on drop.

This is a convenience wrapper around register_user_texture().

Safety & Drop Ordering

The returned token must be dropped before the underlying ImGuiContext is destroyed. If you store it in a struct alongside Context, ensure the token is dropped first.

pub fn unregister_user_texture(&mut self, texture: &mut TextureData)

Unregister a user texture previously registered with register_user_texture().

This removes the ImTextureData* from ImGui’s internal texture list.

pub fn set_ini_filename<P>( &mut self, filename: Option<P>, ) -> Result<(), ImGuiError>

where P: Into<PathBuf>,

Sets the INI filename for settings persistence

Errors

Returns an error if the filename contains null bytes

pub fn set_log_filename<P>( &mut self, filename: Option<P>, ) -> Result<(), ImGuiError>

where P: Into<PathBuf>,

Sets the log filename

Errors

Returns an error if the filename contains null bytes

pub fn set_platform_name<S>( &mut self, name: Option<S>, ) -> Result<(), ImGuiError>

where S: Into<String>,

Sets the platform name

Errors

Returns an error if the name contains null bytes

pub fn set_renderer_name<S>( &mut self, name: Option<S>, ) -> Result<(), ImGuiError>

where S: Into<String>,

Sets the renderer name

Errors

Returns an error if the name contains null bytes

pub fn platform_io_mut(&mut self) -> &mut PlatformIo

Get mutable access to the platform IO.

Note: ImGuiPlatformIO exists even when multi-viewport is disabled. We expose it unconditionally so callers can use ImGui 1.92+ texture management via PlatformIO.Textures[].

pub fn main_viewport(&mut self) -> &Viewport

Returns a reference to the main Dear ImGui viewport.

The returned reference is owned by the currently active ImGui context and must not be used after the context is destroyed.

pub fn suspend(self) -> SuspendedContext

Suspends this context so another context can be the active context

pub fn push_font(&mut self, font: &Font)

Push a font onto the font stack

pub fn pop_font(&mut self)

Pop a font from the font stack

This restores the previous font. Must be paired with a call to push_font().

pub fn current_font(&self) -> &Font

Get the current font

pub fn current_font_size(&self) -> f32

Get the current font size

pub fn font_atlas(&self) -> FontAtlas

Get the font atlas from the IO structure

pub fn font_atlas_mut(&mut self) -> FontAtlas

Get a mutable reference to the font atlas from the IO structure

pub fn fonts(&mut self) -> FontAtlas

Returns the font atlas (alias for font_atlas_mut)

This provides compatibility with imgui-rs naming convention

pub fn clone_shared_font_atlas(&mut self) -> Option<SharedFontAtlas>

Attempts to clone the interior shared font atlas if it exists.

pub fn load_ini_settings(&mut self, data: &str)

Loads settings from a string slice containing settings in .Ini file format

pub fn save_ini_settings(&mut self, buf: &mut String)

Saves settings to a mutable string buffer in .Ini file format

pub fn load_ini_settings_from_disk<P>( &mut self, filename: P, ) -> Result<(), ImGuiError>

where P: Into<PathBuf>,

Loads settings from a .ini file on disk.

This is a convenience wrapper over ImGui::LoadIniSettingsFromDisk.

Note: this is not available on wasm32 targets.

pub fn save_ini_settings_to_disk<P>( &mut self, filename: P, ) -> Result<(), ImGuiError>

where P: Into<PathBuf>,

Saves settings to a .ini file on disk.

This is a convenience wrapper over ImGui::SaveIniSettingsToDisk.

Note: this is not available on wasm32 targets.

pub fn clipboard_text(&self) -> Option<String>

Returns the current clipboard text, if available.

This calls Dear ImGui’s clipboard callbacks (configured via Context::set_clipboard_backend). When no backend is installed, this returns None.

Note: returned data is copied into a new String.

pub fn set_clipboard_text(&self, text: impl AsRef<str>)

Sets the clipboard text.

This calls Dear ImGui’s clipboard callbacks (configured via Context::set_clipboard_backend). If no backend is installed, this is a no-op.

Interior NUL bytes are sanitized to ? to match other scratch-string helpers.

pub fn set_clipboard_backend<T>(&mut self, backend: T)

where T: ClipboardBackend,

Sets the clipboard backend used for clipboard operations

Trait Implementations

impl Debug for Context

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Drop for Context

fn drop(&mut self)

Executes the destructor for this type.