How to load a image/texture then clear it from memory later?

[UnknownSuperficialNight]

I have been using egui::Image::new to load an image from a texture, however, how do I later unload the image from memory?

Here is my Code:

// Struct to hold the values (context)
pub struct Wiki {
    current_images: Arc<Mutex<HashMap<String, ImageData>>>,
    loading_images: Arc<Mutex<HashSet<String>>>, // Track which images are still loading
}

// Struct to hold png image data (context)
struct ImageData {
    data: Vec<u8>,
    width: usize,
    height: usize,
}

// To actually render the image
fn render_image(app_self: &Wiki, ctx: &egui::Context, ui: &mut egui::Ui, image_spec: &ImageSpec) {
let (image_name, max_width, max_height) = match image_spec {
        ImageSpec::Simple(path) => (path, 800.0, 600.0), // Default sizes
        ImageSpec::Detailed { path, max_width, max_height } => (path, max_width.unwrap_or(800.0), max_height.unwrap_or(600.0)),
    };

    if let Ok(images) = app_self.current_images.lock() {
        if let Some(image_data) = images.get(image_name) {
            let texture = ctx.load_texture(image_name, egui::ColorImage::from_rgba_unmultiplied([image_data.width, image_data.height], &image_data.data), egui::TextureOptions::default());

            let aspect_ratio = image_data.width as f32 / image_data.height as f32;
            let display_width = if image_data.width as f32 > max_width { max_width } else { image_data.width as f32 };
            let display_height = display_width / aspect_ratio;
            let display_height = if display_height > max_height { max_height } else { display_height };

            ui.add(egui::Image::new(&texture).max_size(egui::vec2(display_width, display_height)));
        } else if let Ok(loading) = app_self.loading_images.lock() {
            if loading.contains(image_name) {
                ui.spinner();
                ui.label("Loading image...");
            } else {
                ui.colored_label(egui::Color32::RED, "Failed to load image");
            }
        }
    }
}

I clear like this

// Clear existing data
if let Ok(mut images) = self.current_images.lock() {
    images.clear();
}
if let Ok(mut loading) = self.loading_images.lock() {
    loading.clear();
}

However, these are not where the textures are held. From my understanding egui internally holds the textures so either I need to clear the textures interfacing with egui or I need a way to manually handle the textures in current_images inside the Wiki struct

Any ideas on how I can do this?

Or does dereferenceing/clearing it from current_images clear the texture?

Does context.forget_image(uri); work in this instance?

[rustbasic]

Use context.forget_image(uri);.
You can check if it has been cleared in inspection_ui().

        egui::Window::new("🔍 Inspection")
            .open(&mut self.show_inspection)
            .vscroll(true)
            .show(ctx, |ui| {
                ctx.inspection_ui(ui);
            });

[UnknownSuperficialNight]

Thanks for the help, and thanks for the inspection_ui I didn't know about it, really useful :)

[yk0n9]

I have been using egui::Image::new to load an image from a texture, however, how do I later unload the image from memory?

Here is my Code:

// Struct to hold the values (context)
pub struct Wiki {
    current_images: Arc<Mutex<HashMap<String, ImageData>>>,
    loading_images: Arc<Mutex<HashSet<String>>>, // Track which images are still loading
}

// Struct to hold png image data (context)
struct ImageData {
    data: Vec<u8>,
    width: usize,
    height: usize,
}

// To actually render the image
fn render_image(app_self: &Wiki, ctx: &egui::Context, ui: &mut egui::Ui, image_spec: &ImageSpec) {
let (image_name, max_width, max_height) = match image_spec {
        ImageSpec::Simple(path) => (path, 800.0, 600.0), // Default sizes
        ImageSpec::Detailed { path, max_width, max_height } => (path, max_width.unwrap_or(800.0), max_height.unwrap_or(600.0)),
    };

    if let Ok(images) = app_self.current_images.lock() {
        if let Some(image_data) = images.get(image_name) {
            let texture = ctx.load_texture(image_name, egui::ColorImage::from_rgba_unmultiplied([image_data.width, image_data.height], &image_data.data), egui::TextureOptions::default());

            let aspect_ratio = image_data.width as f32 / image_data.height as f32;
            let display_width = if image_data.width as f32 > max_width { max_width } else { image_data.width as f32 };
            let display_height = display_width / aspect_ratio;
            let display_height = if display_height > max_height { max_height } else { display_height };

            ui.add(egui::Image::new(&texture).max_size(egui::vec2(display_width, display_height)));
        } else if let Ok(loading) = app_self.loading_images.lock() {
            if loading.contains(image_name) {
                ui.spinner();
                ui.label("Loading image...");
            } else {
                ui.colored_label(egui::Color32::RED, "Failed to load image");
            }
        }
    }
}

I clear like this

// Clear existing data
if let Ok(mut images) = self.current_images.lock() {
    images.clear();
}
if let Ok(mut loading) = self.loading_images.lock() {
    loading.clear();
}

However, these are not where the textures are held. From my understanding egui internally holds the textures so either I need to clear the textures interfacing with egui or I need a way to manually handle the textures in current_images inside the Wiki struct

Any ideas on how I can do this?

Or does dereferenceing/clearing it from current_images clear the texture?

Does context.forget_image(uri); work in this instance?

https://docs.rs/egui/latest/egui/struct.Context.html#method.forget_all_images

and

https://docs.rs/egui/latest/egui/struct.Context.html#method.forget_image