generate qr code svg (#2815)

* generate qr code svg prototype

* qr code for groups
fix formatting

* - letter avatar in qrcode
- escape xml in userinput (display/groupname)
- fix "Me" display name
- merge import declarations

* remove dot at the end of VerifyContactQRDescription

* if addr == displayname, show only one of them

Especially useful for yggmail accounts without usernames,
because the text would overflow otherwise.

* use real clipPath for rounded avatar

* - center avatar text better (dominant-baseline)
- add "sans-serif" to font fallback for text if arial is missing

* make corner always blue

* add [logo + "get.delta.chat"] footer to qrcode

* Update deltachat-ffi/deltachat.h

Co-authored-by: bjoern <r10s@b44t.com>

* Apply suggestions from code review

Co-authored-by: bjoern <r10s@b44t.com>

* new card design
- add stockstrings
- update changelog

* make qrcode pixels also #f2f2f2 instead of full white

* rename VERIFY_CONTACT_QR_DESC to SETUP_CONTACT
make footer text a tiny bit darker upon r10s's request

* avoid using  which is a doxygen command

* point out that one will join a group (this is still shorted and was also suggested in recent chats)

* add option to generate qr-code-svg to repl tool

* use same font-family in text and footer

* thinner card border

* remove superfluous <tspan> from footer to make color tweaking easier

* move font-weight to style, ios renderer does not pick it up from attribute; remove default font attributes not used consequently

* make get.delta.chat more visible

* align properly using dominant-baseline=central and alignment-baseline=middle, this makes things nice on all systems but android (before, ios was wrong and all others not 100% aligned as font metrics are ignored) (android needs a subsequent improvement)

Co-authored-by: bjoern <r10s@b44t.com>

examples/repl/main.rs

@@ -33,6 +33,8 @@ use rustyline::{
 
 mod cmdline;
 use self::cmdline::*;
+use deltachat::qr_code_generator::get_securejoin_qr_svg;
+use std::fs;
 
 /// Event Handler
 fn receive_event(event: EventType) {
@@ -224,8 +226,9 @@ const CONTACT_COMMANDS: [&str; 9] = [
     "unblock",
     "listblocked",
 ];
-const MISC_COMMANDS: [&str; 11] = [
+const MISC_COMMANDS: [&str; 12] = [
     "getqr",
+    "getqrsvg",
     "getbadqr",
     "checkqr",
     "joinqr",
@@ -427,6 +430,20 @@ async fn handle_cmd(
                 io::stderr().write_all(&output.stderr).unwrap();
             }
         }
+        "getqrsvg" => {
+            ctx.start_io().await;
+            let group = arg1.parse::<u32>().ok().map(|id| ChatId::new(id));
+            let file = dirs::home_dir().unwrap_or_default().join("qr.svg");
+            match get_securejoin_qr_svg(&ctx, group).await {
+                Ok(svg) => {
+                    fs::write(&file, svg)?;
+                    println!("QR code svg written to: {:#?}", file);
+                }
+                Err(err) => {
+                    bail!("Failed to get QR code svg: {}", err);
+                }
+            }
+        }
         "joinqr" => {
             ctx.start_io().await;
             if !arg0.is_empty() {