wiev

Summary

wiev is a simple GPU-accelerated image viewer written in Rust that uses ImageMagick for reading and SFML for rendering the images.

• wiev is adequate. Supported image formats and colorspaces are those of ImageMagick.
• wiev is fast. All transformations, like panning, rotations, and zooming, are handled by the GPU.
• wiev is minimal. The GUI consists of only the rendered image and nothing else.
• wiev is simple. The current codebase is only about 1k SLOC in size and depends only on ImageMagick and SFML.
• wiev is written in Rust. Code modifications can be made without the fear of breaking something unexpectedly.
• wiev is a work in progress. Expect rough edges.

Overview

wiev currently allows the following:

• arbitrary pans, rotations, and zoom levels (there are no artificial limits on these; you can pan past the image borders if you want)
• true horizontal and vertical flips (the actual view is flipped; some programs flip only the underlying image)
• on-the-fly image resampling with respect to scale, rotation, or both using ImageMagick (Lanczos filter is used for downscaling and Mitchell filter for upscaling)
• image state preservation ('you reap what you sow', in a nonnegative sense; currently session bound)
• bookmarks and history (currently session bound)
• texture caching in GPU VRAM (cached images load practically instantaneously, no matter the size)
• textual info overlay (some (less than) meaningful metrics; togglable)

wiev currently does not allow the following:

• non-image input (such will cause a panic; likely to be fixed later)
• any kind of mouse control (keyboard is your friend; likely to be added later)
• image saving, modification, or deletion
• explicit fullscreen mode (window managers can provide this)
• image dimensions exceeding GPU texture size limits (newer GPUs/drivers should allow something like 8Ki or 16Ki px for both dimensions; possibly fixed later)

wiev currently is lacking in the following:

• error handling (nonexistent)
• unit testing (nonexistent)
• documentation (nonexistent)
• command-line interface (rudimentary)
• configuration (hardcoded)

Configuration

wiev currently has various configuration options hardcoded into the global constants in main.rs and wiev.rs. This is likely to be fixed later, but in the meantime feel free to change these; note that especially the FONT_PATH should be changed to a proper one.

Below are excerpts from the source showing the constants; main.rs:

const IMAGE_HOP:      isize = 10;
const IMAGE_HOP_FAST: isize = 100;

const MOVE:      f64 = 10.;   // in px
const MOVE_FAST: f64 = 100.;  // in px
const ROTATE:      f64 = 1.;   // in deg
const ROTATE_FAST: f64 = 30.;  // in deg
const ZOOM:      f64 = 1.044273782427413840321966478739;  // 2^(1/16)
const ZOOM_FAST: f64 = 1.189207115002721066717499970560;  // 2^(1/4)

// const FONT_PATH: &str = "/usr/share/fonts/liberation/LiberationMono-Regular.ttf";
const FONT_PATH: &str = "/usr/share/fonts/noto-cjk/NotoSansCJK-Regular.ttc";
const FONT_SIZE: u32 = 12;
const FONT_FILL_COLOR:    sg::Color = sg::Color::WHITE;
const FONT_OUTLINE_COLOR: sg::Color = sg::Color::BLACK;
const FONT_OUTLINE_THICKNESS: f32 = 2.;

wiev.rs:

const BACKGROUND_COLOR: sg::Color = sg::Color::BLACK;

const TEXTURE_CACHE_MAX_BYTE_SIZE: usize = 1 << 28;  // 256 MiB

const COLORSPACE: mb::ColorspaceType = mb::ColorspaceType_sRGBColorspace;
const DOWNSCALE_FILTER: m::FilterType = mb::FilterType_LanczosFilter;
const UPSCALE_FILTER:   m::FilterType = mb::FilterType_MitchellFilter;

Keybindings

wiev currently has keybindings hardcoded into the handle_event function in main.rs. This is likely to be fixed later, but in the meantime feel free to change these; the key names correspond to the sfml::window::Key enum variants.

Below is an excerpt from the source showing the keybindings:

key!( Escape, a ) | sw::Event::Closed => { wiever.close( window ); },

key!( PageUp )         => { wiever.change_image_index( wIO( -1 ) ); },
key!( PageDown )       => { wiever.change_image_index( wIO(  1 ) ); },
key!( PageUp,   c )    => { wiever.change_image_index( wIO( -IH ) ); },
key!( PageDown, c )    => { wiever.change_image_index( wIO(  IH ) ); },
key!( PageUp,   s )    => { wiever.change_image_index( wIO( -IHF ) ); },
key!( PageDown, s )    => { wiever.change_image_index( wIO(  IHF ) ); },
key!( PageUp,   c, s ) => { wiever.change_image_index( wIS(  0 ) ); },
key!( PageDown, c, s ) => { wiever.change_image_index( wIS( -1 ) ); },
key!( PageDown, a )    => { wiever.change_image_index( wIR ); },

key!( Home )       => { wiever.change_bookmark_index( wIO( -1 ) ); },
key!( End )        => { wiever.change_bookmark_index( wIO(  1 ) ); },
key!( Home, c )    => { wiever.change_bookmark_index( wIO( -IH ) ); },
key!( End,  c )    => { wiever.change_bookmark_index( wIO(  IH ) ); },
key!( Home, s )    => { wiever.change_bookmark_index( wIO( -IHF ) ); },
key!( End,  s )    => { wiever.change_bookmark_index( wIO(  IHF ) ); },
key!( Home, c, s ) => { wiever.change_bookmark_index( wIS(  0 ) ); },
key!( End,  c, s ) => { wiever.change_bookmark_index( wIS( -1 ) ); },
key!( End,  a )    => { wiever.change_bookmark_index( wIR ); },

key!( Insert )       => { wiever.change_history_index( wIO( -1 ) ); },
key!( Delete )       => { wiever.change_history_index( wIO(  1 ) ); },
key!( Insert, c )    => { wiever.change_history_index( wIO( -IH ) ); },
key!( Delete, c )    => { wiever.change_history_index( wIO(  IH ) ); },
key!( Insert, s )    => { wiever.change_history_index( wIO( -IHF ) ); },
key!( Delete, s )    => { wiever.change_history_index( wIO(  IHF ) ); },
key!( Insert, c, s ) => { wiever.change_history_index( wIS(  0 ) ); },
key!( Delete, c, s ) => { wiever.change_history_index( wIS( -1 ) ); },
key!( Delete, a )    => { wiever.change_history_index( wIR ); },

key!( BackSpace )    => { wiever.add_bookmark(); },
key!( BackSpace, c ) => { wiever.remove_bookmark(); },

key!( Numpad0 ) => { wiever.resample_image( wSN, wRN ); },
key!( Numpad1 ) => { wiever.resample_image( wSC, wRC ); },
key!( Numpad2 ) => { wiever.resample_image( wSC, wRN ); },
key!( Numpad3 ) => { wiever.resample_image( wSN, wRC ); },

key!( S )    => { wiever.toggle_texture_smooth(); },
key!( S, c ) => { wiever.toggle_texture_mipmap(); },
// key!( S, s ) => { wiever.toggle_texture_srgb(); },
key!( T )    => { wiever.toggle_text_visible(); },
key!( C )    => { wiever.toggle_cursor_visible(); },
key!( C, c ) => { wiever.clear_texture_cache(); },

key!( Return )    => { wiever.default_(); },
key!( Return, c ) => { wiever.fit_min_dim(); },
key!( Return, s ) => { wiever.fit_max_dim(); },

key!( Space )       => { wiever.reset_zoom(); },
key!( Space, c )    => { wiever.reset_rotation(); },
key!( Space, s )    => { wiever.center(); },
key!( Space, c, s ) => { wiever.reset_flip(); },

key!( Up )       => { wiever.move_( ( 0., -MF ), true, true ); },
key!( Down )     => { wiever.move_( ( 0.,  MF ), true, true ); },
key!( Left )     => { wiever.move_( ( -MF, 0. ), true, true ); },
key!( Right )    => { wiever.move_( (  MF, 0. ), true, true ); },
key!( Up,    s ) => { wiever.move_( ( 0., -M ), true, true ); },
key!( Down,  s ) => { wiever.move_( ( 0.,  M ), true, true ); },
key!( Left,  s ) => { wiever.move_( ( -M, 0. ), true, true ); },
key!( Right, s ) => { wiever.move_( (  M, 0. ), true, true ); },

key!( Up,   c )    => { wiever.zoom( ZF ); },
key!( Down, c )    => { wiever.zoom( ZF.recip() ); },
key!( Up,   c, s ) => { wiever.zoom( Z ); },
key!( Down, c, s ) => { wiever.zoom( Z.recip() ); },

key!( Left,  c )    => { wiever.rotate( -RF ); },
key!( Right, c )    => { wiever.rotate(  RF ); },
key!( Left,  c, s ) => { wiever.rotate( -R ); },
key!( Right, c, s ) => { wiever.rotate(  R ); },

key!( Dash )    => { wiever.hflip(); },
key!( Dash, s ) => { wiever.vflip(); },

Installation

Install stable/nightly Rust and compile with:

• cargo build --release

The compiled executable will be in wiev/target/release/wiev.

The only library dependencies are ImageMagick and SFML, so these should be installed as well.

Usage

• wiev <start_index> <image_path>+

For example:

• wiev 0 a.jpg b.webp c.png # starts at a.jpg
• wiev -1 a.jpg b.webp c.png # starts at c.png
• wiev -42 a.jpg b.webp c.png # starts at whatever the modulo is