Image Viewer

Represents an image that is being rendered under a view-port:

To create an image viewer use ImageViewer::new method (with 4 parameters: an image, a layout, render options, and initialization flags). To understand more on how an image is being rendered or constructed read the Images chapter.

let i = ImageViewer::new(Image::from_str(...).unwrap(), 
                         layout!("x:10,y:5,w:15"),
                         image::RenderOptionsBuilder::new()
                             .scale(image::Scale::Scale50)
                             .character_set(image::CharacterSet::AsciiArt)
                             .build(),
                         imageviewer::Flags::None);

Or use the macro imageviewer!:

let i1 = imageviewer!("x:10,y:5,w:15,scale:50%,charset:AsciiArt");
let i2 = imageviewer!("image:'|R..|,|.R.|,|..R|',x:10,y:5,w:15");

An image viewer supports all common parameters (as they are described in Instantiate via Macros section). Besides them, the following named parameters are also accepted:

An image viewer supports the following initialization flags:

• imageviewer::Flags::ScrollBars or ScrollBars (for macro initialization) - this enables a set of scrollbars that can be used to change the view of the inner surface, but only when the control has focus, as described in Components section.

Some examples that use these parameters:

1. An image viewer with a background that consists of the character X with Aqua and DarkBlue colors.

   let img = imageviewer!("x:10,y:5,w:15,back={X,fore:aqua,back:darkblue}");
   

2. An image viewer with scrollbars with different margins

   let img = imageviewer!("x:10,y:5,w:15,flags:Scrollbars,lsm:5,tsm:1");
   

3. An ASCII art image with scrollbars with different margins and 50% scaling:

   let img = imageviewer!("image:'...',x:10,y:5,w:15,flags:Scrollbars,lsm:5,tsm:1,scale:50%,charset:AsciiArt");
   

4. An image viewer with custom color schema and luminance threshold:

   let img = imageviewer!("image:'|RGB|,|YWr|',x:10,y:5,w:15,color_schema:BlackAndWhite,luminance_threshold:30%");
   

Events

An image viewer control emits no events.

Methods

Besides the Common methods for all Controls an image viewer also has the following additional methods:

Key association

The following keys are processed by an image viewer control if it has focus:

Example

The following code draws a heart with different colors using an ImageViewer:

use appcui::prelude::*;

fn main() -> Result<(), appcui::system::Error> {
    let mut a = App::new().build()?;
    let mut w = window!("Heart,a:c,w:15,h:7");
    let heart = Image::from_str(r#"
        |.............|
        |...rr...rr...|
        |..rrrr.rrrr..|
        |.rrrrrrrrrrr.|
        |.raaaaaaaaar.|
        |..ryyyyyyyr..|
        |   rwwwwwr   |
        |....rwwwr....|
        |.....rwr.....|
        |......r......|
    "#).unwrap();
    w.add(ImageViewer::new(
        heart,
        layout!("d:f"),
        image::RenderOptionsBuilder::new()
            .scale(image::Scale::Scale50)
            .character_set(image::CharacterSet::AsciiArt)
            .color_schema(image::ColorSchema::Color16)
            .build(),
        imageviewer::Flags::None,
    ));
    a.add_window(w);
    a.run();
    Ok(())
}