feat: remove non-sticker heuristics and force_sticker()

This causes problems for Delta Chat Desktop at
<https://github.com/deltachat/deltachat-desktop/pull/6278>
even though the logic was originally introduced for iOS.
If the problem remains on iOS,
heuristics can be added into iOS UI.

deltachat-jsonrpc/src/api.rs

@@ -2379,9 +2379,6 @@ impl CommandApi {
         let mut msg = Message::new(Viewtype::Sticker);
         msg.set_file_and_deduplicate(&ctx, Path::new(&sticker_path), None, None)?;
 
-        // JSON-rpc does not need heuristics to turn [Viewtype::Sticker] into [Viewtype::Image]
-        msg.force_sticker();
-
         let message_id = deltachat::chat::send_msg(&ctx, ChatId::new(chat_id), &mut msg).await?;
         Ok(message_id.to_u32())
     }

deltachat-jsonrpc/src/api/types/message.rs

@@ -287,8 +287,6 @@ pub enum MessageViewtype {
     Gif,
 
     /// Message containing a sticker, similar to image.
-    /// NB: When sending, the message viewtype may be changed to `Image` by some heuristics like
-    /// checking for transparent pixels. Use `Message::force_sticker()` to disable them.
     ///
     /// If possible, the ui should display the image without borders in a transparent way.
     /// A click on a sticker will offer to install the sticker set in some future.

src/blob.rs

@@ -284,10 +284,6 @@ impl<'a> BlobObject<'a> {
     ///
     /// Recoding is only done for [`Viewtype::Image`]. For [`Viewtype::File`], if it's a correct
     /// image, `*viewtype` is set to [`Viewtype::Image`].
-    ///
-    /// On some platforms images are passed to Core as [`Viewtype::Sticker`]. We recheck if the
-    /// image is a true sticker assuming that it must have at least one fully transparent corner,
-    /// otherwise `*viewtype` is set to [`Viewtype::Image`].
     pub async fn check_or_recode_image(
         &mut self,
         context: &Context,

src/blob/blob_tests.rs

@@ -445,7 +445,6 @@ async fn test_recode_image_balanced_png() {
     .await
     .unwrap();
 
-    // This will be sent as Image, see [`BlobObject::check_or_recode_image()`] for explanation.
     SendImageCheckMediaquality {
         viewtype: Viewtype::Sticker,
         media_quality_config: "0",
@@ -453,6 +452,7 @@ async fn test_recode_image_balanced_png() {
         extension: "png",
         original_width: 1920,
         original_height: 1080,
+        res_viewtype: Some(Viewtype::Sticker),
         compressed_width: 1920,
         compressed_height: 1080,
         ..Default::default()
@@ -734,8 +734,6 @@ async fn test_send_gif_as_sticker() -> Result<()> {
     let chat = alice.get_self_chat().await;
     let sent = alice.send_msg(chat.id, &mut msg).await;
     let msg = Message::load_from_db(alice, sent.sender_msg_id).await?;
-    // Message::force_sticker() wasn't used, still Viewtype::Sticker is preserved because of the
-    // extension.
     assert_eq!(msg.get_viewtype(), Viewtype::Sticker);
     Ok(())
 }

src/chat.rs

@@ -2467,10 +2467,7 @@ async fn prepare_msg_blob(context: &Context, msg: &mut Message) -> Result<()> {
             .with_context(|| format!("attachment missing for message of type #{}", msg.viewtype))?;
         let mut maybe_image = false;
 
-        if msg.viewtype == Viewtype::File
-            || msg.viewtype == Viewtype::Image
-            || msg.viewtype == Viewtype::Sticker && !msg.param.exists(Param::ForceSticker)
-        {
+        if msg.viewtype == Viewtype::File || msg.viewtype == Viewtype::Image {
             // Correct the type, take care not to correct already very special
             // formats as GIF or VOICE.
             //
@@ -2478,12 +2475,7 @@ async fn prepare_msg_blob(context: &Context, msg: &mut Message) -> Result<()> {
             // - from FILE to AUDIO/VIDEO/IMAGE
             // - from FILE/IMAGE to GIF */
             if let Some((better_type, _)) = message::guess_msgtype_from_suffix(msg) {
-                if msg.viewtype == Viewtype::Sticker {
-                    if better_type != Viewtype::Image {
-                        // UIs don't want conversions of `Sticker` to anything other than `Image`.
-                        msg.param.set_int(Param::ForceSticker, 1);
-                    }
-                } else if better_type == Viewtype::Image {
+                if better_type == Viewtype::Image {
                     maybe_image = true;
                 } else if better_type != Viewtype::Webxdc
                     || context
@@ -2503,10 +2495,7 @@ async fn prepare_msg_blob(context: &Context, msg: &mut Message) -> Result<()> {
         if msg.viewtype == Viewtype::Vcard {
             msg.try_set_vcard(context, &blob.to_abs_path()).await?;
         }
-        if msg.viewtype == Viewtype::File && maybe_image
-            || msg.viewtype == Viewtype::Image
-            || msg.viewtype == Viewtype::Sticker && !msg.param.exists(Param::ForceSticker)
-        {
+        if msg.viewtype == Viewtype::File && maybe_image || msg.viewtype == Viewtype::Image {
             let new_name = blob
                 .check_or_recode_image(context, msg.get_filename(), &mut msg.viewtype)
                 .await?;

src/chat/chat_tests.rs

@@ -2075,13 +2075,7 @@ async fn test_chat_get_color_encrypted() -> Result<()> {
     Ok(())
 }
 
-async fn test_sticker(
-    filename: &str,
-    bytes: &[u8],
-    res_viewtype: Viewtype,
-    w: i32,
-    h: i32,
-) -> Result<()> {
+async fn test_sticker(filename: &str, bytes: &[u8], w: i32, h: i32) -> Result<()> {
     let alice = TestContext::new_alice().await;
     let bob = TestContext::new_bob().await;
     let alice_chat = alice.create_chat(&bob).await;
@@ -2097,7 +2091,7 @@ async fn test_sticker(
 
     let msg = bob.recv_msg(&sent_msg).await;
     assert_eq!(msg.chat_id, bob_chat.id);
-    assert_eq!(msg.get_viewtype(), res_viewtype);
+    assert_eq!(msg.get_viewtype(), Viewtype::Sticker);
     assert_eq!(msg.get_filename().unwrap(), filename);
     assert_eq!(msg.get_width(), w);
     assert_eq!(msg.get_height(), h);
@@ -2111,7 +2105,6 @@ async fn test_sticker_png() -> Result<()> {
     test_sticker(
         "sticker.png",
         include_bytes!("../../test-data/image/logo.png"),
-        Viewtype::Sticker,
         135,
         135,
     )
@@ -2123,7 +2116,6 @@ async fn test_sticker_jpeg() -> Result<()> {
     test_sticker(
         "sticker.jpg",
         include_bytes!("../../test-data/image/avatar1000x1000.jpg"),
-        Viewtype::Image,
         1000,
         1000,
     )
@@ -2131,10 +2123,33 @@ async fn test_sticker_jpeg() -> Result<()> {
 }
 
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
-async fn test_sticker_jpeg_force() {
-    let alice = TestContext::new_alice().await;
-    let bob = TestContext::new_bob().await;
-    let alice_chat = alice.create_chat(&bob).await;
+async fn test_sticker_gif() -> Result<()> {
+    test_sticker(
+        "sticker.gif",
+        include_bytes!("../../test-data/image/logo.gif"),
+        135,
+        135,
+    )
+    .await
+}
+
+/// Tests that stickers are sent as stickers.
+///
+/// Previously there was heuristic that stickers
+/// were sometimes turned into non-stickers,
+/// e.g. when it looked like UI sent
+/// a screenshot dragged from the gallery into chat
+/// as a sticker.
+///
+/// We have no such heuristic anymore,
+/// if such heuristic is needed on some platform,
+/// UI code should implement it.
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn test_sticker_no_heuristics() {
+    let mut tcm = TestContextManager::new();
+    let alice = &tcm.alice().await;
+    let bob = &tcm.bob().await;
+    let alice_chat = alice.create_chat(bob).await;
 
     let file = alice.get_blobdir().join("sticker.jpg");
     tokio::fs::write(
@@ -2144,53 +2159,38 @@ async fn test_sticker_jpeg_force() {
     .await
     .unwrap();
 
-    // Images without force_sticker should be turned into [Viewtype::Image]
+    // Send a sticker.
     let mut msg = Message::new(Viewtype::Sticker);
-    msg.set_file_and_deduplicate(&alice, &file, Some("sticker.jpg"), None)
+    msg.set_file_and_deduplicate(alice, &file, Some("sticker.jpg"), None)
         .unwrap();
-    let file = msg.get_file(&alice).unwrap();
-    let sent_msg = alice.send_msg(alice_chat.id, &mut msg).await;
-    let msg = bob.recv_msg(&sent_msg).await;
-    assert_eq!(msg.get_viewtype(), Viewtype::Image);
-
-    // Images with `force_sticker = true` should keep [Viewtype::Sticker]
-    let mut msg = Message::new(Viewtype::Sticker);
-    msg.set_file_and_deduplicate(&alice, &file, Some("sticker.jpg"), None)
-        .unwrap();
-    msg.force_sticker();
+    let file = msg.get_file(alice).unwrap();
     let sent_msg = alice.send_msg(alice_chat.id, &mut msg).await;
     let msg = bob.recv_msg(&sent_msg).await;
     assert_eq!(msg.get_viewtype(), Viewtype::Sticker);
 
-    // Images with `force_sticker = true` should keep [Viewtype::Sticker]
-    // even on drafted messages
+    // Send a sticker reusing the file.
     let mut msg = Message::new(Viewtype::Sticker);
-    msg.set_file_and_deduplicate(&alice, &file, Some("sticker.jpg"), None)
+    msg.set_file_and_deduplicate(alice, &file, Some("sticker.jpg"), None)
+        .unwrap();
+    let sent_msg = alice.send_msg(alice_chat.id, &mut msg).await;
+    let msg = bob.recv_msg(&sent_msg).await;
+    assert_eq!(msg.get_viewtype(), Viewtype::Sticker);
+
+    // Set sticker as a draft, then send it.
+    let mut msg = Message::new(Viewtype::Sticker);
+    msg.set_file_and_deduplicate(alice, &file, Some("sticker.jpg"), None)
         .unwrap();
-    msg.force_sticker();
     alice_chat
         .id
-        .set_draft(&alice, Some(&mut msg))
+        .set_draft(alice, Some(&mut msg))
         .await
         .unwrap();
-    let mut msg = alice_chat.id.get_draft(&alice).await.unwrap().unwrap();
+    let mut msg = alice_chat.id.get_draft(alice).await.unwrap().unwrap();
     let sent_msg = alice.send_msg(alice_chat.id, &mut msg).await;
     let msg = bob.recv_msg(&sent_msg).await;
     assert_eq!(msg.get_viewtype(), Viewtype::Sticker);
 }
 
-#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
-async fn test_sticker_gif() -> Result<()> {
-    test_sticker(
-        "sticker.gif",
-        include_bytes!("../../test-data/image/logo.gif"),
-        Viewtype::Sticker,
-        135,
-        135,
-    )
-    .await
-}
-
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn test_sticker_forward() -> Result<()> {
     // create chats

src/message.rs

@@ -795,12 +795,6 @@ impl Message {
         self.viewtype
     }
 
-    /// Forces the message to **keep** [Viewtype::Sticker]
-    /// e.g the message will not be converted to a [Viewtype::Image].
-    pub fn force_sticker(&mut self) {
-        self.param.set_int(Param::ForceSticker, 1);
-    }
-
     /// Returns the state of the message.
     pub fn get_state(&self) -> MessageState {
         self.state
@@ -2322,8 +2316,6 @@ pub enum Viewtype {
     Gif = 21,
 
     /// Message containing a sticker, similar to image.
-    /// NB: When sending, the message viewtype may be changed to `Image` by some heuristics like
-    /// checking for transparent pixels. Use `Message::force_sticker()` to disable them.
     ///
     /// If possible, the ui should display the image without borders in a transparent way.
     /// A click on a sticker will offer to install the sticker set in some future.

src/param.rs

@@ -247,9 +247,6 @@ pub enum Param {
     /// For Webxdc Message Instances: Chat to integrate the Webxdc for.
     WebxdcIntegrateFor = b'2',
 
-    /// For messages: Whether [crate::message::Viewtype::Sticker] should be forced.
-    ForceSticker = b'X',
-
     /// For messages: Message is a deletion request. The value is a list of rfc724_mid of the messages to delete.
     DeleteRequestFor = b'M',