Resize images to columns

CHANGELOG.md

@@ -8,6 +8,13 @@ Use `cargo release` to create a new release.
 
 ## [Unreleased]
 
+### Changed
+- mdcat now uses the kitty protocol to render images on WezTerm (see [GH-258]).
+- mdcat now downscales images to the column limit if rendering with the kitty protocol (see [GH-258]).
+    Previously mdcat scaled down to the window size, which looked strange if a given `--columns` was much smaller than the window size.
+
+[GH-258]: https://github.com/swsnr/mdcat/pull/258
+
 ## [2.0.2] – 2023-04-19
 
 ### Changed

pulldown-cmark-mdcat/src/render.rs

@@ -191,7 +191,7 @@ pub fn write_event<'a, W: Write>(
                 writer,
                 &settings.terminal_capabilities,
                 &settings.theme,
-                settings.terminal_size.columns - (attrs.indent as usize),
+                settings.terminal_size.columns - attrs.indent,
             )?;
             writeln!(writer)?;
             stack
@@ -286,7 +286,7 @@ pub fn write_event<'a, W: Write>(
                     InlineAttrs { style, indent },
                 ))
                 .and_data(data.current_line(CurrentLine {
-                    length: indent as usize,
+                    length: indent,
                     trailing_space: None,
                 }))
                 .ok()
@@ -320,7 +320,7 @@ pub fn write_event<'a, W: Write>(
                 writer,
                 &settings.terminal_capabilities,
                 &settings.theme,
-                settings.terminal_size.columns - (attrs.indent as usize),
+                settings.terminal_size.columns - attrs.indent,
             )?;
             writeln!(writer)?;
             stack
@@ -476,7 +476,7 @@ pub fn write_event<'a, W: Write>(
                 &settings.terminal_capabilities,
                 &settings.theme.code_style.on_top_of(&attrs.style),
                 settings.terminal_size.columns,
-                attrs.indent as usize,
+                attrs.indent,
                 data.current_line,
                 code,
             )?;
@@ -494,7 +494,7 @@ pub fn write_event<'a, W: Write>(
                 &attrs.style,
                 marker,
             )?;
-            let length = data.current_line.length + display_width(marker);
+            let length = data.current_line.length + display_width(marker) as u16;
             Ok(stack
                 .current(Inline(ListItem(kind, state), attrs))
                 .and_data(data.current_line(CurrentLine {
@@ -530,7 +530,7 @@ pub fn write_event<'a, W: Write>(
                 &settings.terminal_capabilities,
                 &attrs.style,
                 settings.terminal_size.columns,
-                attrs.indent as usize,
+                attrs.indent,
                 data.current_line,
                 text,
             )?;
@@ -552,7 +552,7 @@ pub fn write_event<'a, W: Write>(
                 &settings.terminal_capabilities,
                 &attrs.style,
                 settings.terminal_size.columns,
-                attrs.indent as usize,
+                attrs.indent,
                 data.current_line,
                 text,
             )?;
@@ -689,7 +689,7 @@ pub fn write_event<'a, W: Write>(
             let image_state = match (settings.terminal_capabilities.image, resolved_link) {
                 (Some(capability), Some(ref url)) => capability
                     .image_protocol()
-                    .write_inline_image(writer, &resource_handler, url, &settings.terminal_size)
+                    .write_inline_image(writer, &resource_handler, url, settings.terminal_size)
                     .map_err(|error| {
                         event!(Level::ERROR, ?error, %url, "failed to render image with capability {:?}: {:#}", capability, error);
                         error

pulldown-cmark-mdcat/src/render/data.rs

@@ -24,7 +24,7 @@ pub struct LinkReferenceDefinition<'a> {
 #[derive(Debug)]
 pub struct CurrentLine {
     /// The line length
-    pub(super) length: usize,
+    pub(super) length: u16,
     /// Trailing space to add before continuing this line.
     pub(super) trailing_space: Option<String>,
 }

pulldown-cmark-mdcat/src/render/write.rs

@@ -43,14 +43,14 @@ fn write_remaining_lines<W: Write>(
     writer: &mut W,
     capabilities: &TerminalCapabilities,
     style: &Style,
-    indent: usize,
+    indent: u16,
     mut buffer: String,
     next_lines: &[&[Word]],
     last_line: &[Word],
 ) -> Result<CurrentLine> {
     // Finish the previous line
     writeln!(writer)?;
-    write_indent(writer, indent as u16)?;
+    write_indent(writer, indent)?;
     // Now write all lines up to the last
     for line in next_lines {
         match line.split_last() {
@@ -65,7 +65,7 @@ fn write_remaining_lines<W: Write>(
                 buffer.push_str(last.word);
                 write_styled(writer, capabilities, style, &buffer)?;
                 writeln!(writer)?;
-                write_indent(writer, indent as u16)?;
+                write_indent(writer, indent)?;
                 buffer.clear();
             }
         };
@@ -85,7 +85,7 @@ fn write_remaining_lines<W: Write>(
             buffer.push_str(last.word);
             write_styled(writer, capabilities, style, &buffer)?;
             Ok(CurrentLine {
-                length: textwrap::core::display_width(&buffer),
+                length: textwrap::core::display_width(&buffer) as u16,
                 trailing_space: Some(last.whitespace.to_owned()),
             })
         }
@@ -96,8 +96,8 @@ pub fn write_styled_and_wrapped<W: Write, S: AsRef<str>>(
     writer: &mut W,
     capabilities: &TerminalCapabilities,
     style: &Style,
-    max_width: usize,
-    indent: usize,
+    max_width: u16,
+    indent: u16,
     current_line: CurrentLine,
     text: S,
 ) -> Result<CurrentLine> {
@@ -113,14 +113,16 @@ pub fn write_styled_and_wrapped<W: Write, S: AsRef<str>>(
                 + current_line
                     .trailing_space
                     .as_ref()
-                    .map_or(0, |s| display_width(s.as_ref()));
+                    .map_or(0, |s| display_width(s.as_ref()) as u16);
 
             // If the current line is not empty and we can't even add the first first word of the text to it
             // then lets finish the line and start over.  If the current line is empty the word simply doesn't
             // fit into the terminal size so we must print it anyway.
-            if 0 < current_line.length && max_width < current_width + display_width(first_word) {
+            if 0 < current_line.length
+                && max_width < current_width + display_width(first_word) as u16
+            {
                 writeln!(writer)?;
-                write_indent(writer, indent as u16)?;
+                write_indent(writer, indent)?;
                 return write_styled_and_wrapped(
                     writer,
                     capabilities,
@@ -146,7 +148,7 @@ pub fn write_styled_and_wrapped<W: Write, S: AsRef<str>>(
                     Ok(current_line)
                 }
                 Some((first_line, tails)) => {
-                    let mut buffer = String::with_capacity(max_width);
+                    let mut buffer = String::with_capacity(max_width as usize);
 
                     // Finish the current line
                     let new_current_line = match first_line.split_last() {
@@ -164,7 +166,7 @@ pub fn write_styled_and_wrapped<W: Write, S: AsRef<str>>(
                             }
                             buffer.push_str(last.word);
                             let length =
-                                current_line.length + textwrap::core::display_width(&buffer);
+                                current_line.length + textwrap::core::display_width(&buffer) as u16;
                             write_styled(writer, capabilities, style, &buffer)?;
                             buffer.clear();
                             CurrentLine {
@@ -214,9 +216,9 @@ pub fn write_rule<W: Write>(
     writer: &mut W,
     capabilities: &TerminalCapabilities,
     theme: &Theme,
-    length: usize,
+    length: u16,
 ) -> std::io::Result<()> {
-    let rule = "\u{2550}".repeat(length);
+    let rule = "\u{2550}".repeat(length as usize);
     write_styled(
         writer,
         capabilities,
@@ -231,7 +233,7 @@ pub fn write_code_block_border<W: Write>(
     capabilities: &TerminalCapabilities,
     terminal_size: &TerminalSize,
 ) -> std::io::Result<()> {
-    let separator = "\u{2500}".repeat(terminal_size.columns.min(20));
+    let separator = "\u{2500}".repeat(terminal_size.columns.min(20) as usize);
     write_styled(
         writer,
         capabilities,

pulldown-cmark-mdcat/src/resources.rs

@@ -13,7 +13,7 @@ use mime::Mime;
 use url::Url;
 
 mod file;
-mod image;
+pub(crate) mod image;
 
 pub(crate) mod svg;
 

pulldown-cmark-mdcat/src/resources/image.rs

@@ -31,6 +31,38 @@ pub trait InlineImageProtocol {
         writer: &mut dyn Write,
         resource_handler: &dyn ResourceUrlHandler,
         url: &Url,
-        terminal_size: &TerminalSize,
+        terminal_size: TerminalSize,
     ) -> std::io::Result<()>;
 }
+
+/// Downsize an image to the given terminal size.
+///
+/// If the `image` is larger than the amount of columns in the given terminal `size` attempt to
+/// downsize the image to fit into the given columns.
+///
+/// Return the downsized image if `image` was larger than the column limit and `size` defined the
+/// terminal size in pixels.
+///
+/// Return `None` if `size` does not specify the cell size, or if `image` is already smaller than
+/// the column limit.
+#[cfg(feature = "image-processing")]
+pub fn downsize_to_columns(
+    image: &image::DynamicImage,
+    size: TerminalSize,
+) -> Option<image::DynamicImage> {
+    use image::{imageops::FilterType, GenericImageView};
+    use tracing::{event, Level};
+    let win_size = size.pixels?;
+    event!(
+        Level::DEBUG,
+        "Terminal size {:?}; image is {:?}",
+        size,
+        image.dimensions()
+    );
+    let (image_width, _) = image.dimensions();
+    if win_size.x < image_width {
+        Some(image.resize(win_size.x, win_size.y, FilterType::Nearest))
+    } else {
+        None
+    }
+}

pulldown-cmark-mdcat/src/terminal/capabilities/iterm2.rs

@@ -46,7 +46,7 @@ impl InlineImageProtocol for ITerm2 {
         writer: &mut dyn Write,
         resource_handler: &dyn ResourceUrlHandler,
         url: &url::Url,
-        _terminal_size: &crate::TerminalSize,
+        _terminal_size: crate::TerminalSize,
     ) -> Result<()> {
         let mime_data = resource_handler.read_resource(url)?;
         event!(