Support the reMarkable Paper Pro Move by detecting geometry at runtime

riddle/src/display.rs

@@ -28,6 +28,11 @@ mod quill_ffi {
 impl Display {
     pub fn open() -> io::Result<(Self, Surface)> {
         if let Ok(key) = std::env::var("QTFB_KEY") {
+            // Windowed AppLoad mode. FBFMT_RMPP_RGB565 is a Paper Pro
+            // ("ferrari") -specific wire format (see qtfb.rs), so this path
+            // is Ferrari-only; riddle ships with "qtfb": false in its
+            // manifest and always runs via takeover (below) instead. A
+            // Move-native qtfb format would need its own investigation.
             let key: i32 = key.parse().map_err(io::Error::other)?;
             let mut client = crate::qtfb::QtfbClient::connect(
                 key,

riddle/src/fb.rs

@@ -1,7 +1,34 @@
 //! Geometry helpers. Drawing lives in surface.rs.
 
-pub const SCREEN_W: usize = 1620;
-pub const SCREEN_H: usize = 2160;
+use std::sync::OnceLock;
+
+// Panel size varies by device (Paper Pro: 1620x2160, Paper Pro Move:
+// 960x1696) and isn't known until the display backend opens and reports
+// the real aux/qtfb framebuffer geometry. `init_screen` sets it once, early
+// in `main`; every reader after that goes through `screen_w`/`screen_h`.
+static SCREEN_DIMS: OnceLock<(usize, usize)> = OnceLock::new();
+
+pub fn init_screen(w: usize, h: usize) {
+    let _ = SCREEN_DIMS.set((w, h));
+}
+
+pub fn screen_w() -> usize {
+    SCREEN_DIMS.get().expect("init_screen not called before screen_w").0
+}
+
+pub fn screen_h() -> usize {
+    SCREEN_DIMS.get().expect("init_screen not called before screen_h").1
+}
+
+/// Tests exercise geometry helpers without ever opening a display, so they
+/// need `init_screen` called explicitly. Any dimensions work for a test;
+/// this uses the Paper Pro's so tests match the values they were written
+/// against. Idempotent (and safe under parallel test execution) since it's
+/// the same `OnceLock::set` `init_screen` itself uses.
+#[cfg(test)]
+pub fn test_init_screen() {
+    init_screen(1620, 2160);
+}
 
 /// Grow-only pixel bounding box, used to build update/dissolve regions.
 #[derive(Clone, Copy, Debug)]
@@ -22,8 +49,8 @@ impl BBox {
     pub fn add(&mut self, x: i32, y: i32, margin: i32) {
         self.x0 = self.x0.min(x - margin).max(0);
         self.y0 = self.y0.min(y - margin).max(0);
-        self.x1 = self.x1.max(x + margin).min(SCREEN_W as i32 - 1);
-        self.y1 = self.y1.max(y + margin).min(SCREEN_H as i32 - 1);
+        self.x1 = self.x1.max(x + margin).min(screen_w() as i32 - 1);
+        self.y1 = self.y1.max(y + margin).min(screen_h() as i32 - 1);
     }
     pub fn rect(&self) -> (i32, i32, i32, i32) {
         (self.x0, self.y0, self.x1 - self.x0 + 1, self.y1 - self.y0 + 1)

riddle/src/help.rs

@@ -2,7 +2,7 @@
 //! the diary's gestures; touching the pen to the page dismisses it. Detection
 //! is local geometry — no oracle — so the guide works even with no network.
 
-use crate::fb::{BBox, SCREEN_H, SCREEN_W};
+use crate::fb::{screen_h, screen_w, BBox};
 use crate::script;
 use crate::surface::{Surface, BLACK, WHITE};
 use ab_glyph::FontRef;
@@ -154,10 +154,10 @@ pub fn show(surf: &mut Surface, font: &FontRef, takeover: bool) -> Help {
     for l in body {
         wmax = wmax.max(script::measure(font, l, BODY_PX));
     }
-    let pw = (wmax as usize + 2 * PAD).min(SCREEN_W - 40);
+    let pw = (wmax as usize + 2 * PAD).min(screen_w() - 40);
     let ph = PAD + title_h + line_h / 2 + body.len() * line_h + footer_h + PAD;
-    let px = (SCREEN_W - pw) / 2;
-    let py = (SCREEN_H.saturating_sub(ph)) / 2;
+    let px = (screen_w() - pw) / 2;
+    let py = (screen_h().saturating_sub(ph)) / 2;
 
     let saved = surf.copy_rect(px, py, pw, ph);
     surf.fill_rect(px, py, pw, ph, WHITE);
@@ -192,18 +192,18 @@ impl Help {
 /// Replace the page with the full-screen sleep card; returns the saved page
 /// pixels so waking can restore them exactly.
 pub fn show_sleep(surf: &mut Surface, font: &FontRef) -> Vec<u8> {
-    let saved = surf.copy_rect(0, 0, SCREEN_W, SCREEN_H);
-    surf.fill_rect(0, 0, SCREEN_W, SCREEN_H, WHITE);
-    frame(surf, 48, 48, SCREEN_W - 96, SCREEN_H - 96, 4);
-    frame(surf, 66, 66, SCREEN_W - 132, SCREEN_H - 132, 1);
-    let y = SCREEN_H * 38 / 100;
-    blit_centered(surf, font, "The diary sleeps.", 116.0, 0, SCREEN_W, y);
-    blit_centered(surf, font, "Press the button to wake it.", 56.0, 0, SCREEN_W, y + 230);
+    let saved = surf.copy_rect(0, 0, screen_w(), screen_h());
+    surf.fill_rect(0, 0, screen_w(), screen_h(), WHITE);
+    frame(surf, 48, 48, screen_w() - 96, screen_h() - 96, 4);
+    frame(surf, 66, 66, screen_w() - 132, screen_h() - 132, 1);
+    let y = screen_h() * 38 / 100;
+    blit_centered(surf, font, "The diary sleeps.", 116.0, 0, screen_w(), y);
+    blit_centered(surf, font, "Press the button to wake it.", 56.0, 0, screen_w(), y + 230);
     saved
 }
 
 pub fn restore_sleep(surf: &mut Surface, saved: &[u8]) {
-    surf.paste_rect(0, 0, SCREEN_W, SCREEN_H, saved);
+    surf.paste_rect(0, 0, screen_w(), screen_h(), saved);
 }
 
 fn frame(surf: &mut Surface, x: usize, y: usize, w: usize, h: usize, t: usize) {
@@ -290,7 +290,8 @@ mod tests {
 
     #[test]
     fn modal_renders_and_restores() {
-        let (w, h) = (SCREEN_W, SCREEN_H);
+        crate::fb::test_init_screen();
+        let (w, h) = (screen_w(), screen_h());
         let mut buf = vec![0xFFu8; w * h * 4];
         let ptr = buf.as_mut_ptr();
         let mut surf = Surface::new(ptr, buf.len(), w, h, w * 4, crate::surface::PixFmt::Rgb32);
@@ -336,7 +337,8 @@ mod tests {
 
     #[test]
     fn sleep_page_renders_and_restores() {
-        let (w, h) = (SCREEN_W, SCREEN_H);
+        crate::fb::test_init_screen();
+        let (w, h) = (screen_w(), screen_h());
         let mut buf = vec![0xFFu8; w * h * 4];
         let ptr = buf.as_mut_ptr();
         let mut surf = Surface::new(ptr, buf.len(), w, h, w * 4, crate::surface::PixFmt::Rgb32);

riddle/src/ink.rs

@@ -185,6 +185,7 @@ mod tests {
 
     #[test]
     fn erase_forgets_covered_points_and_splits_strokes() {
+        crate::fb::test_init_screen();
         let (_buf, mut s) = surf();
         let mut ink = Ink::new();
         // A horizontal stroke across the page.
@@ -210,6 +211,7 @@ mod tests {
 
     #[test]
     fn erasing_everything_empties_the_ink() {
+        crate::fb::test_init_screen();
         let (_buf, mut s) = surf();
         let mut ink = Ink::new();
         ink.pen_point(&mut s, 100, 100, 3);