pixelcoords_core/

emit.rs

//! Ready-to-paste click snippets from a session — the logic behind
//! `pixelcoords emit`.
//!
//! Each emitter encodes one automation tool's coordinate convention in
//! exactly one place, because that conversion is where hand-written glue
//! gets silently burned: pyautogui speaks logical points on macOS but
//! physical pixels on Windows and X11; cliclick speaks logical points;
//! xdotool speaks physical pixels. Coordinates are the session's own
//! `global_px`, divided by the selection's monitor scale only where the
//! target tool wants logical points. Sessions are machine-local, so a
//! snippet is meant to run on the machine and monitor layout that was
//! captured.

use std::fmt::Write as _;

use thiserror::Error;

use crate::geometry::Point;
use crate::session::{SelectionRecord, SessionFile};

#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum EmitFormat {
    Pyautogui,
    Cliclick,
    Xdotool,
}

/// The OS the snippet will run on. Only pyautogui branches on it — the
/// other tools each exist on a single platform.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum Platform {
    MacOs,
    Windows,
    Linux,
}

#[derive(Debug, Error, PartialEq, Eq)]
pub enum EmitError {
    #[error("the session has no selections to emit")]
    NoSelections,
    #[error("no selection is labeled {requested:?}; labels in this session: {available:?}")]
    UnknownLabel {
        requested: String,
        available: Vec<String>,
    },
    #[error(
        "selection {selection} references monitor {monitor}, which the \
         session does not describe"
    )]
    UnknownMonitor { selection: usize, monitor: usize },
}

/// The units a target tool expects its coordinates in.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
enum Units {
    Physical,
    Logical,
}

/// One click the snippet will perform.
struct Target {
    comment: String,
    point: Point,
}

/// Render the session's selections as a ready-to-paste snippet for
/// `format`, ending with a newline.
pub fn emit(
    session: &SessionFile,
    format: EmitFormat,
    platform: Platform,
    label: Option<&str>,
) -> Result<String, EmitError> {
    match format {
        EmitFormat::Pyautogui => pyautogui(session, platform, label),
        EmitFormat::Cliclick => cliclick(session, label),
        EmitFormat::Xdotool => xdotool(session, label),
    }
}

fn pyautogui(
    session: &SessionFile,
    platform: Platform,
    label: Option<&str>,
) -> Result<String, EmitError> {
    let (units, space_note) = match platform {
        Platform::MacOs => (Units::Logical, "logical points (macOS)"),
        // pyautogui makes its process DPI-aware on import, so it addresses
        // true physical pixels on Windows.
        Platform::Windows => (Units::Physical, "physical pixels (Windows)"),
        Platform::Linux => (Units::Physical, "physical pixels (X11)"),
    };
    let targets = click_targets(session, units, label)?;
    let mut out = header("#", session, space_note);
    out.push_str("import pyautogui\n");
    for t in targets {
        // Writing to a String cannot fail.
        let _ = write!(
            out,
            "\n# {}\npyautogui.click({}, {})\n",
            t.comment, t.point.x, t.point.y
        );
    }
    Ok(out)
}

fn cliclick(session: &SessionFile, label: Option<&str>) -> Result<String, EmitError> {
    let targets = click_targets(session, Units::Logical, label)?;
    let mut out = header("#", session, "logical points (macOS)");
    for t in targets {
        let _ = writeln!(
            out,
            "cliclick c:{},{}  # {}",
            cliclick_coord(t.point.x),
            cliclick_coord(t.point.y),
            t.comment
        );
    }
    Ok(out)
}

/// cliclick parses a bare leading `-` as an option; its documented escape
/// for negative coordinates is an `=` prefix.
fn cliclick_coord(v: i32) -> String {
    if v < 0 {
        return format!("={v}");
    }
    v.to_string()
}

fn xdotool(session: &SessionFile, label: Option<&str>) -> Result<String, EmitError> {
    let targets = click_targets(session, Units::Physical, label)?;
    let mut out = header("#", session, "physical pixels (X11)");
    for t in targets {
        let _ = writeln!(
            out,
            "xdotool mousemove {} {} click 1  # {}",
            t.point.x, t.point.y, t.comment
        );
    }
    Ok(out)
}

fn header(prefix: &str, session: &SessionFile, space_note: &str) -> String {
    format!(
        "{prefix} generated by pixelcoords from a session captured {}\n\
         {prefix} coordinates: {space_note} — run on the machine and \
         monitor layout that was captured\n",
        session.created_utc
    )
}

/// Every selection's click point in global coordinates, converted to the
/// requested units via its own monitor's scale — mixed-DPI setups scale
/// each selection independently.
fn click_targets(
    session: &SessionFile,
    units: Units,
    label: Option<&str>,
) -> Result<Vec<Target>, EmitError> {
    if session.selections.is_empty() {
        return Err(EmitError::NoSelections);
    }
    let wanted: Vec<(usize, &SelectionRecord)> = session
        .selections
        .iter()
        .enumerate()
        .filter(|(_, record)| label.is_none_or(|wanted| record.label.eq_ignore_ascii_case(wanted)))
        .collect();
    if wanted.is_empty() {
        // Only a label filter can empty a non-empty session.
        let mut available: Vec<String> = Vec::new();
        for record in &session.selections {
            let known = record.label.is_empty()
                || available
                    .iter()
                    .any(|l| l.eq_ignore_ascii_case(&record.label));
            if !known {
                available.push(record.label.clone());
            }
        }
        return Err(EmitError::UnknownLabel {
            requested: label.unwrap_or_default().to_string(),
            available,
        });
    }
    wanted
        .into_iter()
        .map(|(index, record)| {
            // The click point of the stored global shape. Rect rotation
            // pivots on the bbox center — the click point itself — so
            // `rot_deg` cannot move it; triangles store rotation baked.
            let physical = record.global_px.click_point();
            let point = match units {
                Units::Physical => physical,
                Units::Logical => to_logical(session, index, record, physical)?,
            };
            Ok(Target {
                comment: describe(index, record),
                point,
            })
        })
        .collect()
}

/// `global_px` divided by the selection's monitor scale. Monitor origins
/// were scaled by that same per-monitor factor when the session was
/// written, so the division inverts cleanly even across mixed DPI.
fn to_logical(
    session: &SessionFile,
    index: usize,
    record: &SelectionRecord,
    physical: Point,
) -> Result<Point, EmitError> {
    let monitor = session
        .monitors
        .iter()
        .find(|m| m.index == record.monitor)
        .ok_or(EmitError::UnknownMonitor {
            selection: index,
            monitor: record.monitor,
        })?;
    Ok(Point::new(
        (f64::from(physical.x) / monitor.scale).round() as i32,
        (f64::from(physical.y) / monitor.scale).round() as i32,
    ))
}

fn describe(index: usize, record: &SelectionRecord) -> String {
    let shape = match record.shape {
        crate::geometry::ToolKind::Rect => "rect",
        crate::geometry::ToolKind::Circle => "circle",
        crate::geometry::ToolKind::Ellipse => "ellipse",
        crate::geometry::ToolKind::Polygon
        | crate::geometry::ToolKind::Freehand
        | crate::geometry::ToolKind::Poly => "poly",
        crate::geometry::ToolKind::Triangle => "triangle",
    };
    if record.label.is_empty() {
        return format!("selection {index} — {shape} on monitor {}", record.monitor);
    }
    format!("{} — {shape} on monitor {}", record.label, record.monitor)
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::geometry::{Rect, Shape, Size};
    use crate::selection::Selection;
    use crate::session::MonitorRecord;

    fn monitor(index: usize, ox: i32, oy: i32, scale: f64) -> MonitorRecord {
        MonitorRecord {
            index,
            name: format!("Display {index}"),
            primary: index == 0,
            origin_px: Point::new(ox, oy),
            size_px: Size::new(1920, 1080),
            scale,
        }
    }

    fn labeled(shape: Shape, monitor: usize, label: &str) -> Selection {
        let mut sel = Selection::new(shape, monitor);
        sel.label = label.into();
        sel
    }

    fn session(monitors: Vec<MonitorRecord>, selections: &[Selection]) -> SessionFile {
        let crops: Vec<String> = (0..selections.len()).map(|i| format!("c{i}.png")).collect();
        SessionFile::build(
            "test",
            "2026-07-27T11:35:42Z".into(),
            monitors,
            selections,
            &crops,
            None,
        )
    }

    #[test]
    fn pyautogui_on_macos_emits_logical_points() {
        // Rect center at physical (100, 60) on a 2x monitor -> (50, 30).
        let file = session(
            vec![monitor(0, 0, 0, 2.0)],
            &[labeled(Shape::Rect(Rect::new(80, 40, 40, 40)), 0, "submit")],
        );
        let out = emit(&file, EmitFormat::Pyautogui, Platform::MacOs, None).unwrap();
        assert_eq!(
            out,
            "# generated by pixelcoords from a session captured 2026-07-27T11:35:42Z\n\
             # coordinates: logical points (macOS) — run on the machine and \
             monitor layout that was captured\n\
             import pyautogui\n\
             \n\
             # submit — rect on monitor 0\n\
             pyautogui.click(50, 30)\n"
        );
    }

    #[test]
    fn pyautogui_elsewhere_emits_physical_pixels() {
        let file = session(
            vec![monitor(0, 0, 0, 2.0)],
            &[labeled(Shape::Rect(Rect::new(80, 40, 40, 40)), 0, "submit")],
        );
        for (platform, note) in [
            (Platform::Windows, "physical pixels (Windows)"),
            (Platform::Linux, "physical pixels (X11)"),
        ] {
            let out = emit(&file, EmitFormat::Pyautogui, platform, None).unwrap();
            assert!(out.contains("pyautogui.click(100, 60)"), "got: {out}");
            assert!(out.contains(note), "got: {out}");
        }
    }

    #[test]
    fn cliclick_escapes_negative_logical_coordinates() {
        // A monitor left of the primary: global physical (-1800, 40) at
        // scale 2 -> logical (-900, 20), with cliclick's `=` escape.
        let file = session(
            vec![monitor(0, -3840, 0, 2.0)],
            &[labeled(Shape::Rect(Rect::new(2020, 20, 40, 40)), 0, "back")],
        );
        let out = emit(&file, EmitFormat::Cliclick, Platform::MacOs, None).unwrap();
        assert!(
            out.contains("cliclick c:=-900,20  # back — rect on monitor 0"),
            "got: {out}"
        );
    }

    #[test]
    fn xdotool_emits_physical_pixels_untouched() {
        let file = session(
            vec![monitor(0, 0, 0, 2.0)],
            &[labeled(
                Shape::Circle {
                    cx: 500,
                    cy: 300,
                    r: 25,
                },
                0,
                "dot",
            )],
        );
        let out = emit(&file, EmitFormat::Xdotool, Platform::Linux, None).unwrap();
        assert!(
            out.contains("xdotool mousemove 500 300 click 1  # dot — circle on monitor 0"),
            "got: {out}"
        );
    }

    #[test]
    fn mixed_dpi_scales_each_selection_by_its_own_monitor() {
        let file = session(
            vec![monitor(0, 0, 0, 1.0), monitor(1, 1920, 0, 2.0)],
            &[
                labeled(Shape::Rect(Rect::new(100, 100, 20, 20)), 0, "left"),
                labeled(Shape::Rect(Rect::new(100, 100, 20, 20)), 1, "right"),
            ],
        );
        let out = emit(&file, EmitFormat::Pyautogui, Platform::MacOs, None).unwrap();
        // Monitor 0 at scale 1: physical (110, 110) stays put. Monitor 1 at
        // scale 2: global physical (2030, 110) -> logical (1015, 55).
        assert!(out.contains("pyautogui.click(110, 110)"), "got: {out}");
        assert!(out.contains("pyautogui.click(1015, 55)"), "got: {out}");
    }

    #[test]
    fn triangles_click_their_centroid_and_unlabeled_selections_get_names() {
        let file = session(
            vec![monitor(0, 0, 0, 1.0)],
            &[labeled(
                Shape::Triangle {
                    ax: 30,
                    ay: 0,
                    bx: 0,
                    by: 60,
                    cx: 60,
                    cy: 60,
                },
                0,
                "",
            )],
        );
        let out = emit(&file, EmitFormat::Xdotool, Platform::Linux, None).unwrap();
        assert!(
            out.contains("xdotool mousemove 30 40 click 1  # selection 0 — triangle on monitor 0"),
            "got: {out}"
        );
    }

    #[test]
    fn a_rotated_rect_clicks_its_pivot() {
        let mut sel = Selection::new(Shape::Rect(Rect::new(10, 10, 40, 10)), 0);
        sel.rot_deg = 90;
        let file = session(vec![monitor(0, 0, 0, 1.0)], &[sel]);
        let out = emit(&file, EmitFormat::Xdotool, Platform::Linux, None).unwrap();
        // The pivot (30, 15) is rotation-invariant, so the click lands
        // inside the silhouette at any angle.
        assert!(
            out.contains("xdotool mousemove 30 15 click 1"),
            "got: {out}"
        );
    }

    #[test]
    fn a_label_filter_emits_only_matching_selections() {
        let file = session(
            vec![monitor(0, 0, 0, 1.0)],
            &[
                labeled(Shape::Rect(Rect::new(0, 0, 10, 10)), 0, "Cancel"),
                labeled(Shape::Rect(Rect::new(100, 100, 10, 10)), 0, "Submit"),
            ],
        );
        let out = emit(&file, EmitFormat::Xdotool, Platform::Linux, Some("submit")).unwrap();
        assert!(out.contains("xdotool mousemove 105 105"), "got: {out}");
        assert!(!out.contains("mousemove 5 5"), "got: {out}");
        // The comment keeps the selection's original session index.
        assert!(out.contains("Submit — rect on monitor 0"), "got: {out}");

        let err = emit(&file, EmitFormat::Xdotool, Platform::Linux, Some("send")).unwrap_err();
        assert_eq!(
            err,
            EmitError::UnknownLabel {
                requested: "send".into(),
                available: vec!["Cancel".into(), "Submit".into()],
            }
        );
    }

    #[test]
    fn an_empty_session_is_an_error() {
        let file = session(vec![monitor(0, 0, 0, 1.0)], &[]);
        let err = emit(&file, EmitFormat::Xdotool, Platform::Linux, None).unwrap_err();
        assert_eq!(err, EmitError::NoSelections);
    }

    #[test]
    fn a_selection_on_an_undescribed_monitor_is_an_error_for_logical_units() {
        let file = session(
            vec![monitor(0, 0, 0, 2.0)],
            &[labeled(Shape::Rect(Rect::new(0, 0, 10, 10)), 3, "orphan")],
        );
        let err = emit(&file, EmitFormat::Cliclick, Platform::MacOs, None).unwrap_err();
        assert_eq!(
            err,
            EmitError::UnknownMonitor {
                selection: 0,
                monitor: 3,
            }
        );
        // Physical units never look the monitor up, so the same session
        // still emits for xdotool.
        assert!(emit(&file, EmitFormat::Xdotool, Platform::Linux, None).is_ok());
    }
}