qrcode_paintable: Use an upscaled texture

This is more efficient and draws without gaps in betweek black squares.

src/widgets/accounts/qrcode_paintable.rs

@@ -1,35 +1,22 @@
-use gtk::{gdk, glib, graphene, prelude::*, subclass::prelude::*};
+use gtk::{gdk, glib, graphene, gsk, prelude::*, subclass::prelude::*};
 
 #[allow(clippy::upper_case_acronyms)]
 pub struct QRCodeData {
-    pub width: i32,
-    pub height: i32,
-    pub items: Vec<Vec<bool>>,
+    pub size: i32,
+    pub items: Vec<bool>,
 }
 
 impl<B: AsRef<[u8]>> From<B> for QRCodeData {
     fn from(data: B) -> Self {
         let code = qrencode::QrCode::new(data).unwrap();
         let items = code
-            .render::<char>()
-            .quiet_zone(false)
-            .module_dimensions(1, 1)
-            .build()
-            .split('\n')
-            .map(|line| {
-                line.chars()
-                    .map(|c| !c.is_whitespace())
-                    .collect::<Vec<bool>>()
-            })
-            .collect::<Vec<Vec<bool>>>();
+            .to_colors()
+            .iter()
+            .map(|color| matches!(color, qrencode::types::Color::Dark))
+            .collect::<Vec<bool>>();
 
-        let width = items.first().unwrap().len() as i32;
-        let height = items.len() as i32;
-        Self {
-            width,
-            height,
-            items,
-        }
+        let size = code.width() as i32;
+        Self { size, items }
     }
 }
 
@@ -55,30 +42,23 @@ mod imp {
     impl PaintableImpl for QRCodePaintable {
         fn snapshot(&self, snapshot: &gdk::Snapshot, width: f64, height: f64) {
             if let Some(ref qrcode) = *self.qrcode.borrow() {
-                let padding_squares = 3.max(qrcode.height / 10);
-                let square_height = height as f32 / (qrcode.height + 2 * padding_squares) as f32;
-                let square_width = width as f32 / (qrcode.width + 2 * padding_squares) as f32;
+                let padding_squares = 3.max(qrcode.size / 10);
+                let square_height = height as f32 / (qrcode.size + 2 * padding_squares) as f32;
+                let square_width = width as f32 / (qrcode.size + 2 * padding_squares) as f32;
                 let padding = square_height * padding_squares as f32;
 
                 let rect = graphene::Rect::new(0.0, 0.0, width as f32, height as f32);
                 snapshot.append_color(&gdk::RGBA::WHITE, &rect);
-                qrcode.items.iter().enumerate().for_each(|(y, line)| {
-                    line.iter().enumerate().for_each(|(x, is_dark)| {
-                        if *is_dark {
-                            let mut black = gdk::RGBA::BLACK;
-                            black.set_alpha(0.85);
 
-                            let position = graphene::Rect::new(
-                                (x as f32) * square_width + padding,
-                                (y as f32) * square_height + padding,
-                                square_width,
-                                square_height,
-                            );
+                let inner_rect = graphene::Rect::new(
+                    padding,
+                    padding,
+                    square_width * qrcode.size as f32,
+                    square_height * qrcode.size as f32,
+                );
 
-                            snapshot.append_color(&black, &position);
-                        };
-                    });
-                });
+                let texture = texture(qrcode);
+                snapshot.append_scaled_texture(&texture, gsk::ScalingFilter::Nearest, &inner_rect);
             }
         }
     }
@@ -101,3 +81,21 @@ impl Default for QRCodePaintable {
         glib::Object::new()
     }
 }
+
+fn texture(qrcode: &QRCodeData) -> gdk::Texture {
+    let size = qrcode.size;
+
+    const G8_SIZE: usize = 1;
+    const WHITE: u8 = 0xff; // #ffffff
+    const BLACK: u8 = 0x24; // #242424
+
+    let bytes: Vec<u8> = qrcode
+        .items
+        .iter()
+        .map(|is_black| if *is_black { BLACK } else { WHITE })
+        .collect();
+    let bytes = glib::Bytes::from_owned(bytes);
+    let stride = G8_SIZE * size as usize;
+
+    gdk::MemoryTexture::new(size, size, gdk::MemoryFormat::G8, &bytes, stride).upcast()
+}