feat: add delta chat logo to QR codes (#6093)

the chosen error correction allows tolerates about 15% "erroneous
codewords", the logo is of a similar size as the old avatars,
so it should be fine.

assets/qr_overlay_delta.svg-part

@@ -0,0 +1,12 @@
+<path
+   style="fill:#ffffff;fill-opacity:1;stroke:none"
+   d="m 24.015419,1.2870249 c -12.549421,0 -22.7283936,10.1789711 -22.7283936,22.7283931 0,12.549422 10.1789726,22.728395 22.7283936,22.728395 14.337742,-0.342877 9.614352,-4.702705 23.697556,0.969161 -7.545453,-13.001555 -1.082973,-13.32964 -0.969161,-23.697556 0,-12.549422 -10.178973,-22.7283931 -22.728395,-22.7283931 z" />
+<path
+   style="fill:#000000;fill-opacity:1;stroke:none"
+   d="M 23.982249,5.3106163 C 13.645822,5.4364005 5.2618355,13.92999 5.2618355,24.275753 c 0,10.345764 8.3839865,18.635301 18.7204135,18.509516 9.827724,-0.03951 7.516769,-5.489695 18.380082,-0.443187 -5.950849,-9.296115 0.201753,-10.533667 0.340336,-18.521947 0,-10.345766 -8.383989,-18.6353031 -18.720418,-18.5095187 z" />
+<g
+    style="fill:#ffffff"
+    transform="scale(1.1342891,0.88160947)">
+  <path
+     d="m 21.360141,23.513382 q -1.218487,-1.364705 -3.387392,-3.265543 -2.388233,-2.095797 -3.216804,-3.289913 -0.828571,-1.218486 -0.828571,-2.6563 0,-2.144536 1.998318,-3.363022 1.998317,-1.2428565 5.215121,-1.2428565 3.216804,0 5.605037,1.0966375 2.412603,1.096638 2.412603,3.021846 0,0.92605 -0.584873,1.535293 -0.584874,0.609243 -1.364705,0.609243 -1.121008,0 -2.631931,-1.681511 -1.535292,-1.705881 -2.60756,-2.388233 -1.047898,-0.706722 -2.461343,-0.706722 -1.803359,0 -2.973106,0.804201 -1.145377,0.804201 -1.145377,2.047057 0,1.169747 0.950419,2.193275 0.950419,1.023529 4.898315,3.728568 4.215963,2.899998 5.946213,4.532769 1.75462,1.632772 2.851258,3.972265 1.096638,2.339494 1.096638,4.947055 0,4.581508 -3.241174,8.090749 -3.216804,3.484871 -7.530245,3.484871 -3.923526,0 -6.628566,-2.802519 -2.705039,-2.802518 -2.705039,-7.481506 0,-4.508399 2.973106,-7.530245 2.997477,-3.021846 7.359658,-3.655459 z m 1.072268,1.121008 q -6.994112,1.145377 -6.994112,9.601672 0,4.36218 1.730251,6.774783 1.75462,2.412603 4.069744,2.412603 2.412603,0 3.972265,-2.315124 1.559663,-2.339493 1.559663,-6.311759 0,-5.751255 -4.337811,-10.162175 z" />
+</g>

src/qr_code_generator.rs

@@ -18,6 +18,7 @@ use crate::stock_str::{self, backup_transfer_qr};
 pub fn create_qr_svg(qrcode_content: &str) -> Result<String> {
     let all_size = 512.0;
     let qr_code_size = 416.0;
+    let logo_size = 96.0;
 
     let qr = QrCode::encode_text(qrcode_content, QrCodeEcc::Medium)?;
     let mut svg = String::with_capacity(28000);
@@ -67,7 +68,18 @@ pub fn create_qr_svg(qrcode_content: &str) -> Result<String> {
                 d.attr("d", path_data)?;
                 d.attr("transform", format!("scale({scale})"))
             })
-        })
+        })?;
+        w.elem("g", |d| {
+            d.attr(
+                "transform",
+                format!(
+                    "translate({},{}) scale(2)", // data in qr_overlay_delta.svg-part are 48 x 48, scaling by 2 results in desired logo_size of 96
+                    (all_size - logo_size) / 2.0,
+                    (all_size - logo_size) / 2.0
+                ),
+            )
+        })?
+        .build(|w| w.put_raw_escapable(include_str!("../assets/qr_overlay_delta.svg-part")))
     })?;
 
     Ok(svg)