cosmic-files/src/large_image.rs
Vukašin Vojinović 1e25e7dd69 chore: clippy
2026-01-30 21:05:46 +01:00

599 lines
22 KiB
Rust

use cosmic::widget;
use image::ImageReader;
use std::{
collections::{HashMap, HashSet},
path::{Path, PathBuf},
};
/// Bytes per pixel in RGBA format (Red, Green, Blue, Alpha = 4 bytes)
pub const RGBA_BYTES_PER_PIXEL: u64 = 4;
/// System memory reserve in MB to maintain for system stability (prevents thrashing)
/// Note: RAM checking is currently only available on Linux via procfs.
/// On Windows and macOS, only GPU buffer limits are enforced.
const SYSTEM_MEMORY_RESERVE_MB: u64 = 500;
/// Maximum memory allocation for gallery image decoding in MB.
/// Gallery mode uses the full memory budget since only one image decodes at a time.
/// This matches the ThumbCfg max_mem_mb budget for consistency.
const GALLERY_MEMORY_LIMIT_MB: u64 = 2000;
/// Threshold for considering an image "large" requiring GPU tiling
/// Atlas fragment/tile size in pixels. Large images are split into fragments of this size.
/// Must match the atlas SIZE constant in libcosmic/iced/wgpu/src/image/atlas.rs
pub const ATLAS_FRAGMENT_SIZE: u32 = 4096;
/// Conversion factor: 1 MB = 1024 * 1024 bytes (binary megabyte, used for RAM calculations)
pub const MB_TO_BYTES: u64 = 1024 * 1024;
/// Conversion factor: 1 MB = 1000 * 1000 bytes (decimal megabyte, used by image crate)
/// The image crate's memory limits use decimal MB, not binary MB.
pub const DECIMAL_MB_TO_BYTES: u64 = 1000 * 1000;
/// Scale factor for HiDPI displays - decode at higher resolution than display size
/// for better quality on high-DPI screens. 1.5x provides good balance between
/// quality and memory usage and also prevets re-decoding on small windows size adjustments.
const DISPLAY_SCALE_FACTOR: f32 = 1.5;
/// Calculate optimal target dimensions for decoding based on display size.
/// Returns None if no resizing is needed (image is smaller than display).
///
/// This helps reduce memory usage by decoding large images at a resolution
/// appropriate for the display, rather than always using full resolution.
pub fn calculate_target_dimensions(
image_width: u32,
image_height: u32,
display_width: u32,
display_height: u32,
) -> Option<(u32, u32)> {
let target_width = (display_width as f32 * DISPLAY_SCALE_FACTOR) as u32;
let target_height = (display_height as f32 * DISPLAY_SCALE_FACTOR) as u32;
if image_width <= target_width && image_height <= target_height {
return None;
}
let image_aspect = image_width as f32 / image_height as f32;
let target_aspect = target_width as f32 / target_height as f32;
let (new_width, new_height) = if image_aspect > target_aspect {
let w = target_width;
let h = (target_width as f32 / image_aspect) as u32;
(w, h)
} else {
let h = target_height;
let w = (target_height as f32 * image_aspect) as u32;
(w, h)
};
let new_width = new_width.max(1);
let new_height = new_height.max(1);
log::info!(
"Calculated target dimensions: {}x{} -> {}x{} (display: {}x{}, scale: {}x)",
image_width,
image_height,
new_width,
new_height,
display_width,
display_height,
DISPLAY_SCALE_FACTOR
);
Some((new_width, new_height))
}
/// Check if an image's dimensions would exceed the available memory budget.
/// Returns true if the image is too large to decode.
pub fn exceeds_memory_limit(width: u32, height: u32, memory_limit_mb: u64) -> bool {
let Some(bytes_needed) = calculate_image_memory(width, height) else {
// Overflow in calculation means it definitely exceeds any reasonable limit
return true;
};
let max_bytes = memory_limit_mb * MB_TO_BYTES;
bytes_needed > max_bytes
}
/// Check if an image should use GPU tiling for display.
/// Images larger than the atlas fragment size need to be split into tiles for GPU upload.
pub fn should_use_tiling(width: u32, height: u32) -> bool {
width > ATLAS_FRAGMENT_SIZE || height > ATLAS_FRAGMENT_SIZE
}
/// Determine if an image should use the dedicated worker for thumbnail generation.
/// Returns (use_dedicated_worker, effective_max_mb, effective_jobs).
///
/// Large images that exceed per-worker memory budget get routed to a dedicated worker
/// with full memory budget. Smaller images use the normal parallel worker pool.
pub fn should_use_dedicated_worker(
width: u32,
height: u32,
total_budget_mb: u64,
parallel_workers: usize,
) -> (bool, u64, usize) {
if width == 0 || height == 0 {
log::warn!(
"Invalid image dimensions {}x{}, using normal queue",
width,
height
);
return (false, total_budget_mb, parallel_workers);
}
let Some(bytes_needed) = calculate_image_memory(width, height) else {
log::warn!(
"Image dimensions {}x{} overflow memory calculation, using normal queue",
width,
height
);
return (false, total_budget_mb, parallel_workers);
};
let mb_needed = bytes_needed / MB_TO_BYTES;
let per_worker_budget_mb = total_budget_mb / parallel_workers as u64;
if mb_needed > per_worker_budget_mb {
log::info!(
"Large image {}x{} needs {}MB (exceeds per-worker {}MB), using dedicated worker",
width,
height,
mb_needed,
per_worker_budget_mb
);
// Use dedicated worker with full budget
(true, total_budget_mb, 1)
} else {
log::debug!(
"Normal image {}x{} needs {}MB (within per-worker {}MB), using parallel workers",
width,
height,
mb_needed,
per_worker_budget_mb
);
// Use parallel worker pool with shared budget
(false, total_budget_mb, parallel_workers)
}
}
/// Get the dimensions of an image without fully decoding it
pub fn get_image_dimensions(path: &Path) -> Option<(u32, u32)> {
match ImageReader::open(path) {
Ok(reader) => match reader.into_dimensions() {
Ok((width, height)) => {
log::debug!(
"Image dimensions: {}x{} for {}",
width,
height,
path.display()
);
Some((width, height))
}
Err(e) => {
log::warn!("Failed to get dimensions for {}: {}", path.display(), e);
None
}
},
Err(e) => {
log::warn!("Failed to open image reader for {}: {}", path.display(), e);
None
}
}
}
/// Calculate the memory required to decode an image in bytes.
/// Returns None if the calculation overflows.
fn calculate_image_memory(width: u32, height: u32) -> Option<u64> {
let pixels = (width as u64).checked_mul(height as u64)?;
pixels.checked_mul(RGBA_BYTES_PER_PIXEL)
}
/// Check if there's sufficient system RAM to decode an image (Linux only).
/// Returns: (has_memory, error_message)
#[cfg(target_os = "linux")]
fn check_ram_available(width: u32, height: u32) -> (bool, Option<String>) {
use procfs::Current;
let Some(bytes_needed) = calculate_image_memory(width, height) else {
let error_msg = format!(
"Image dimensions too large: {}x{} causes overflow in memory calculation",
width, height
);
log::error!("{}", error_msg);
return (false, Some(error_msg));
};
let mb_needed = bytes_needed / MB_TO_BYTES;
match procfs::Meminfo::current() {
Ok(meminfo) => {
// MemAvailable includes reclaimable cache and is the best estimate of
// actually available memory for new allocations
let available_kb = meminfo.mem_available.unwrap_or(0);
let available_bytes = available_kb * 1024;
// Maintain system reserve to prevent thrashing and OOM killer
let min_reserve_bytes = SYSTEM_MEMORY_RESERVE_MB * MB_TO_BYTES;
let usable_bytes = available_bytes.saturating_sub(min_reserve_bytes);
if bytes_needed > usable_bytes {
let available_mb = available_bytes / MB_TO_BYTES;
let error_msg = format!(
"Insufficient memory: need {}MB, available {}MB. Try closing other applications.",
mb_needed, available_mb
);
log::warn!("{}", error_msg);
return (false, Some(error_msg));
}
(true, None)
}
Err(e) => {
log::warn!("Failed to read /proc/meminfo: {}. Skipping RAM check.", e);
// Graceful fallback: assume RAM is available
(true, None)
}
}
}
#[cfg(not(target_os = "linux"))]
fn check_ram_available(_width: u32, _height: u32) -> (bool, Option<String>) {
// RAM checking not implemented for this platform
(true, None)
}
pub fn check_memory_available(width: u32, height: u32) -> (bool, Option<String>) {
if width == 0 || height == 0 {
let error_msg = format!(
"Invalid image dimensions: {}x{} (zero dimension)",
width, height
);
log::error!("{}", error_msg);
return (false, Some(error_msg));
}
// Check system RAM availability
check_ram_available(width, height)
}
/// Decode a large image asynchronously in a blocking thread pool.
///
/// This function is used for gallery mode where full-resolution images need to be loaded.
/// It uses the full memory budget (GALLERY_MEMORY_LIMIT_MB) since only one image
/// decodes at a time in gallery mode.
pub async fn decode_large_image(
path: PathBuf,
target_dimensions: Option<(u32, u32)>,
) -> Option<(PathBuf, u32, u32, Vec<u8>)> {
// Decode image in blocking thread pool (CPU-intensive work should not block)
tokio::task::spawn_blocking(move || {
log::info!("Starting async decode of {}", path.display());
// Use ImageReader with explicit memory limits to avoid "Memory limit exceeded" errors
// Gallery mode uses the full memory budget since only one image decodes at a time
match image::ImageReader::open(&path) {
Ok(reader) => {
match reader.with_guessed_format() {
Ok(mut reader) => {
// Note: image crate uses decimal MB (1000^2), not binary MB (1024^2)
let mut limits = image::Limits::default();
limits.max_alloc = Some(GALLERY_MEMORY_LIMIT_MB * DECIMAL_MB_TO_BYTES);
reader.limits(limits);
match reader.decode() {
Ok(img) => {
let rgba = img.into_rgba8();
let orig_width = rgba.width();
let orig_height = rgba.height();
// Resize if target dimensions provided
let (final_img, width, height) = if let Some((target_w, target_h)) = target_dimensions {
log::info!(
"Resizing {}x{} -> {}x{} for memory optimization: {}",
orig_width, orig_height, target_w, target_h,
path.display()
);
// Use Lanczos3 for high-quality downsampling
let resized = image::imageops::resize(
&rgba,
target_w,
target_h,
image::imageops::FilterType::Lanczos3,
);
let resized_w = resized.width();
let resized_h = resized.height();
log::info!(
"Resize complete: {}x{} image now uses ~{} MB instead of ~{} MB",
resized_w, resized_h,
(resized_w as u64 * resized_h as u64 * 4) / MB_TO_BYTES,
(orig_width as u64 * orig_height as u64 * 4) / MB_TO_BYTES
);
(resized, resized_w, resized_h)
} else {
log::info!(
"Decoded {}x{} image at full resolution: {}",
orig_width, orig_height,
path.display()
);
(rgba, orig_width, orig_height)
};
let pixels = final_img.into_raw();
Some((path, width, height, pixels))
}
Err(e) => {
log::warn!("Failed to decode {}: {}", path.display(), e);
None
}
}
}
Err(e) => {
log::warn!("Failed to guess format for {}: {}", path.display(), e);
None
}
}
}
Err(e) => {
log::warn!("Failed to open {}: {}", path.display(), e);
None
}
}
})
.await
.ok()
.flatten()
}
/// Manages state and operations for large image decoding in gallery mode
#[derive(Debug, Default)]
pub struct LargeImageManager {
/// Paths of images currently being decoded
decoding_images: HashSet<PathBuf>,
/// Cache of decoded image handles
decoded_images: HashMap<PathBuf, widget::image::Handle>,
/// Display dimensions used for each decoded image (for resize detection)
decoded_display_sizes: HashMap<PathBuf, (u32, u32)>,
/// Errors encountered during decoding
decode_errors: HashMap<PathBuf, String>,
/// Generation counter for each decode to support cancellation.
/// When a new decode is started for the same path, the generation is incremented.
/// Only decodes matching the current generation are accepted when they complete.
decode_generations: HashMap<PathBuf, u64>,
}
impl LargeImageManager {
pub fn new() -> Self {
Self::default()
}
pub fn is_decoding(&self, path: &Path) -> bool {
self.decoding_images.contains(path)
}
pub fn get_decoded(&self, path: &Path) -> Option<&widget::image::Handle> {
self.decoded_images.get(path)
}
pub fn get_error(&self, path: &Path) -> Option<&String> {
self.decode_errors.get(path)
}
/// Store a decoded image if the generation matches (not superseded by newer decode).
/// Returns true if stored, false if rejected due to generation mismatch.
pub fn store_decoded_with_generation(
&mut self,
path: PathBuf,
handle: widget::image::Handle,
display_size: Option<(u32, u32)>,
generation: u64,
) -> bool {
// Check if this decode is still current (not superseded by a newer one)
if let Some(&current_gen) = self.decode_generations.get(&path)
&& generation != current_gen
{
log::info!(
"Discarding outdated decode for {} (generation {} != current {})",
path.display(),
generation,
current_gen
);
return false;
}
log::info!(
"Storing decoded image for {} (generation {})",
path.display(),
generation
);
self.decoded_images.insert(path.clone(), handle);
if let Some(size) = display_size {
self.decoded_display_sizes.insert(path.clone(), size);
}
self.decoding_images.remove(&path);
true
}
pub fn store_error(&mut self, path: PathBuf, error: String) {
self.decode_errors.insert(path.clone(), error);
self.decoding_images.remove(&path);
}
pub fn clear_error(&mut self, path: &Path) {
self.decode_errors.remove(path);
}
pub fn clear_cache(&mut self) {
log::info!(
"Clearing {} cached images from large image manager",
self.decoded_images.len()
);
self.decoded_images.clear();
}
pub fn cache_size(&self) -> usize {
self.decoded_images.len()
}
pub fn cache_is_empty(&self) -> bool {
self.decoded_images.is_empty()
}
/// Check if an image should be re-decoded due to display size increase.
/// Returns true only if the display size has INCREASED by more than 20% in either dimension.
/// Does NOT re-decode for smaller sizes (GPU can efficiently downscale).
pub fn needs_redecode_for_size(
&self,
path: &Path,
new_display_size: Option<(u32, u32)>,
) -> bool {
let Some(new_size) = new_display_size else {
return false;
};
let Some(&old_size) = self.decoded_display_sizes.get(path) else {
return false;
};
const REDECODE_THRESHOLD: f32 = 0.2;
let width_increase = (new_size.0 as f32 / old_size.0 as f32) - 1.0;
let height_increase = (new_size.1 as f32 / old_size.1 as f32) - 1.0;
let needs_redecode =
width_increase > REDECODE_THRESHOLD || height_increase > REDECODE_THRESHOLD;
if needs_redecode {
log::info!(
"Display size increased significantly for {}: {}x{} -> {}x{} (increase: {:.1}% width, {:.1}% height) - re-decoding at higher resolution",
path.display(),
old_size.0,
old_size.1,
new_size.0,
new_size.1,
width_increase * 100.0,
height_increase * 100.0
);
} else if width_increase < -REDECODE_THRESHOLD || height_increase < -REDECODE_THRESHOLD {
log::debug!(
"Display size decreased for {}: {}x{} -> {}x{} (decrease: {:.1}% width, {:.1}% height) - keeping existing higher resolution",
path.display(),
old_size.0,
old_size.1,
new_size.0,
new_size.1,
width_increase * 100.0,
height_increase * 100.0
);
}
needs_redecode
}
/// Attempt to decode a large image, checking memory availability first.
/// Returns (should_decode, target_dimensions, generation) tuple.
pub fn try_decode(
&mut self,
path: &PathBuf,
display_dimensions: Option<(u32, u32)>,
) -> (bool, Option<(u32, u32)>, u64) {
self.clear_error(path);
let is_currently_decoding = self.is_decoding(path);
let needs_redecode = self.needs_redecode_for_size(path, display_dimensions);
if is_currently_decoding && !needs_redecode {
// Get current generation for the ongoing decode
let generation = self.decode_generations.get(path).copied().unwrap_or(0);
return (false, None, generation);
}
if self.get_decoded(path).is_some() && !needs_redecode && !is_currently_decoding {
let generation = self.decode_generations.get(path).copied().unwrap_or(0);
return (false, None, generation);
}
let Some((width, height)) = get_image_dimensions(path) else {
self.store_error(path.clone(), "Failed to read image dimensions".to_string());
return (false, None, 0);
};
let target_dimensions = if let Some((display_w, display_h)) = display_dimensions {
calculate_target_dimensions(width, height, display_w, display_h)
} else {
None
};
// Check memory for target size (if resizing) or full size
let (check_w, check_h) = target_dimensions.unwrap_or((width, height));
if !self.ensure_memory_available(path, check_w, check_h) {
return (false, None, 0);
}
// Increment generation counter (cancels any previous decode)
let generation = self
.decode_generations
.entry(path.clone())
.and_modify(|g| *g += 1)
.or_insert(1);
let generation = *generation;
if is_currently_decoding {
log::info!(
"Cancelling previous decode for {} and starting new one (generation {})",
path.display(),
generation
);
}
// Mark as decoding
self.decoding_images.insert(path.clone());
(true, target_dimensions, generation)
}
/// Check if sufficient memory is available, clearing cache if needed.
/// Returns true if memory is available, false otherwise.
fn ensure_memory_available(&mut self, path: &Path, width: u32, height: u32) -> bool {
let (has_memory, error_opt) = check_memory_available(width, height);
if has_memory {
return true;
}
if self.cache_is_empty() {
if let Some(error_msg) = error_opt {
self.store_error(path.to_path_buf(), error_msg);
log::warn!(
"Cannot load {}: insufficient memory and cache is empty",
path.display()
);
}
return false;
}
log::info!(
"Insufficient memory, clearing {} cached images",
self.cache_size()
);
self.clear_cache();
let (has_memory_after_clear, error_opt_after) = check_memory_available(width, height);
if has_memory_after_clear {
log::info!("Memory available after cache clear, proceeding with decode");
return true;
}
if let Some(error_msg) = error_opt_after {
self.store_error(path.to_path_buf(), error_msg);
log::warn!(
"Cannot load {}: insufficient memory even after cache clear",
path.display()
);
}
false
}
}