AlanGriffiths · AlanGriffiths · Mar 27, 2026 · Mar 27, 2026
diff --git a/calibrate-touchscreen/src/main.rs b/calibrate-touchscreen/src/main.rs
@@ -62,7 +62,14 @@ impl FullscreenSurface {
         let width = self.width;
         let height = self.height;
 
-        let mut file = tempfile::tempfile().unwrap();
+        let mut file = match tempfile::tempfile() {
+            Ok(f) => f,
+            Err(e) => {
+                eprintln!("Failed to create temporary buffer file: {}", e);
+                return;
+            }
+        };
+
         draw_with_target(&mut file, (width, height), TARGETS[targets_index]);
         let pool = wl_shm.create_pool(file.as_fd(), width * height * 4, qh, ());
         let buffer = pool.create_buffer(
@@ -79,6 +86,7 @@ impl FullscreenSurface {
         self.wl_surface.damage(0, 0, width, height);
         self.wl_surface.commit();
         buffer.destroy();
+        pool.destroy();
     }
 }
 
@@ -191,6 +199,7 @@ impl Dispatch<WlOutput, ()> for State {
 fn draw_with_target(tmp: &mut File, (buf_x, buf_y): (i32, i32), (target_x, target_y): (f64, f64)) {
     let centre_x = (buf_x as f64 * target_x) as i64;
     let centre_y = (buf_y as f64 * target_y) as i64;
+    // Target circle size is 1/80th of the screen size for easy visibility and accurate touching
     let target_size = (max(buf_x, buf_y) / 80) as i64;
     use std::io::Write;
     let mut buf = std::io::BufWriter::new(tmp);
@@ -199,13 +208,16 @@ fn draw_with_target(tmp: &mut File, (buf_x, buf_y): (i32, i32), (target_x, targe
             let distance_squared =
                 (x - centre_x) * (x - centre_x) + (y - centre_y) * (y - centre_y);
             if distance_squared >= target_size * target_size {
+                // Outside target circle: draw gradient background
+                // ARGB8888 format: [B, G, R, A]
                 let a = 0xFF;
                 let r = 0x3F;
                 let g = 0x3F * y as i32 / buf_y;
                 let b = 0x3F * y as i32 / buf_y;
                 buf.write_all(&[b as u8, g as u8, r as u8, a as u8])
                     .unwrap();
             } else {
+                // Inside target circle: draw white circle with smooth edges
                 let intensity = 0xFF - 0x40 * (distance_squared / (target_size * target_size / 4));
                 let a = 0xFF;
                 buf.write_all(&[intensity as u8, intensity as u8, intensity as u8, a as u8])
@@ -280,6 +292,13 @@ impl InitialisedState {
                 * (self.touches[1].1 - self.touches[2].1)
                 - (self.touches[1].0 - self.touches[2].0) * (self.touches[0].1 - self.touches[2].1);
 
+            // Check for collinear points (determinant close to zero)
+            if k.abs() < 1e-6 {
+                eprintln!("Error: touched points are collinear or too close together. Cannot calibrate.");
+                eprintln!("Please touch the three targets more accurately and ensure they form a triangle.");
+                return;
+            }
+
             let ak = (TARGETS[0].0 - TARGETS[2].0) * (self.touches[1].1 - self.touches[2].1)
                 - (TARGETS[1].0 - TARGETS[2].0) * (self.touches[0].1 - self.touches[2].1);
 
@@ -512,11 +531,9 @@ impl Dispatch<xdg_surface::XdgSurface, ()> for State {
         match event {
             xdg_surface::Event::Configure { serial } => {
                 proxy.ack_configure(serial);
-                state
-                    .initialised
-                    .as_mut()
-                    .unwrap()
-                    .draw_fullscreen_surfaces(qhandle);
+                if let Some(init) = state.initialised.as_mut() {
+                    init.draw_fullscreen_surfaces(qhandle);
+                }
             }
             _ => {}
         }

diff --git a/snap/snapcraft.yaml b/snap/snapcraft.yaml
@@ -1,6 +1,6 @@
 name: libinput
-version: "22.04"
-base: core22
+version: "24.04"
+base: core24
 summary: libinput-tools helpful in debugging libinput
 description: |
   - list-devices:
@@ -28,26 +28,29 @@ description: |
   Bonus utility to help with touchscreen calibration.
   https://mir-server.io/docs/howto-calibrate-a-touchscreen-device
 
-website: https://github.com/AlanGriffiths/libinput
+title: libinput
+website:     https://github.com/AlanGriffiths/libinput
+source-code: https://github.com/AlanGriffiths/libinput
+issues:  https://github.com/AlanGriffiths/libinput/issues
 contact: https://github.com/AlanGriffiths/libinput/issues
 license: Apache-2.0
 
 grade: stable
 confinement: strict
 
-architectures:
-  - build-on: amd64
-  - build-on: armhf
-  - build-on: arm64
-  - build-on: ppc64el
+platforms:
+  amd64:
+  armhf:
+  arm64:
+  ppc64el:
 
 layout:
   /usr/share/drirc.d:
     bind: $SNAP/graphics/drirc.d
   /usr/share/X11/xkb:
     bind: $SNAP/usr/share/X11/xkb
-  /usr/lib/$SNAPCRAFT_ARCH_TRIPLET/gdk-pixbuf-2.0:
-    bind: $SNAP/usr/lib/$SNAPCRAFT_ARCH_TRIPLET/gdk-pixbuf-2.0
+  /usr/lib/${CRAFT_ARCH_TRIPLET_BUILD_FOR}/gdk-pixbuf-2.0:
+    bind: $SNAP/usr/lib/${CRAFT_ARCH_TRIPLET_BUILD_FOR}/gdk-pixbuf-2.0
   /usr/share/mime:
     bind: $SNAP/usr/share/mime
   /etc/gtk-3.0:
@@ -58,10 +61,10 @@ layout:
     symlink: $SNAP/usr/share/libinput
 
 plugs:
-  graphics-core22:
+  gpu-2404:
     interface: content
-    target: $SNAP/graphics
-    default-provider: mesa-core22
+    target: $SNAP/gpu-2404
+    default-provider: mesa-2404
 
 apps:
   list-devices:
@@ -80,7 +83,7 @@ apps:
       - raw-input
       - wayland
     command-chain:
-      - bin/graphics-core22-wrapper
+      - bin/gpu-2404-wrapper
       - bin/wayland-launch
     command: usr/bin/libinput debug-gui
 
@@ -108,7 +111,7 @@ apps:
     plugs:
       - wayland
     command-chain:
-      - bin/graphics-core22-wrapper
+      - bin/gpu-2404-wrapper
       - bin/wayland-launch
     command: bin/calibrate-touchscreen
 
@@ -136,32 +139,31 @@ parts:
       - shared-mime-info
     override-build: |
       # Update mime database
-      update-mime-database ${SNAPCRAFT_PART_INSTALL}/usr/share/mime
+      update-mime-database ${CRAFT_PART_INSTALL}/usr/share/mime
     stage-packages:
       - librsvg2-common
       - gsettings-desktop-schemas
       - libglib2.0-bin
     override-prime: |
-      snapcraftctl prime
+      craftctl default
       # Compile the gsettings schemas
-      /usr/lib/${SNAPCRAFT_ARCH_TRIPLET}/glib-2.0/glib-compile-schemas "$SNAPCRAFT_PRIME/usr/share/glib-2.0/schemas"
+      /usr/lib/${CRAFT_ARCH_TRIPLET_BUILD_FOR}/glib-2.0/glib-compile-schemas "$CRAFT_PRIME/usr/share/glib-2.0/schemas"
       # Index the pixbuf loaders
-      LOADERS_PATH=$(echo ${SNAPCRAFT_PRIME}/usr/lib/${SNAPCRAFT_ARCH_TRIPLET}/gdk-pixbuf-2.0/*/loaders)
-      QUERY_LOADERS=/usr/lib/${SNAPCRAFT_ARCH_TRIPLET}/gdk-pixbuf-2.0/gdk-pixbuf-query-loaders
+      LOADERS_PATH=$(echo ${CRAFT_PRIME}/usr/lib/${CRAFT_ARCH_TRIPLET_BUILD_FOR}/gdk-pixbuf-2.0/*/loaders)
+      QUERY_LOADERS=/usr/lib/${CRAFT_ARCH_TRIPLET_BUILD_FOR}/gdk-pixbuf-2.0/gdk-pixbuf-query-loaders
       GDK_PIXBUF_MODULEDIR=${LOADERS_PATH} ${QUERY_LOADERS} > ${LOADERS_PATH}/../loaders.cache
-      sed s!$SNAPCRAFT_PRIME!!g --in-place ${LOADERS_PATH}/../loaders.cache
+      sed s!$CRAFT_PRIME!!g --in-place ${LOADERS_PATH}/../loaders.cache
 
-  graphics-core22:
+  gpu-2404:
     after:
       - scripts
       - libinput-tools
       - gtkstuff
       - calibrate-touchscreen
-    source: https://github.com/MirServer/graphics-core22.git
+    source: https://github.com/canonical/gpu-snap.git
     plugin: dump
     override-prime: |
       craftctl default
-      ${CRAFT_PART_SRC}/bin/graphics-core22-cleanup mesa-core22
-      rm -rf ${CRAFT_PRIME}/usr/share/{doc,man}
+      ${CRAFT_PART_SRC}/bin/gpu-2404-cleanup mesa-2404 nvidia-2404
     prime:
-      - bin/graphics-core22-wrapper
+      - bin/gpu-2404-wrapper