feat: Use resize when resampling images with up to 2.56 megapixels

src/blob.rs

@@ -437,15 +437,13 @@ impl<'a> BlobObject<'a> {
                         self::add_white_bg(&mut img);
                     }
 
-                    // resize() results in often slightly better quality,
-                    // however, comes at high price of being 4+ times slower than thumbnail().
-                    // for a typical camera image that is sent, this may be a change from "instant" (500ms) to "long time waiting" (3s).
-                    // as we do not have recoding in background while chat has already a preview,
-                    // we vote for speed.
-                    // exception is the avatar image: this is far more often sent than recoded,
-                    // usually has less pixels by cropping, UI that needs to wait anyways,
-                    // and also benefits from slightly better (5%) encoding of Triangle-filtered images.
-                    let new_img = if is_avatar {
+                    // resize() results in better quality than thumbnail(),
+                    // however, comes at the price of being 4+ times slower.
+                    // For a typical camera-image that is sent (often more than 8 megapixels),
+                    // this may be a change from "instant" (500ms) to "long time waiting" (3s).
+                    // As we do not have recoding in the background while the chat already has a preview,
+                    // we vote for speed, if the original image has a high resolution (> 2.56 megapixels).
+                    let new_img = if is_avatar || img.width() * img.height() <= 1600 * 1600 {
                         img.resize(target_wh, target_wh, image::imageops::FilterType::Triangle)
                     } else {
                         img.thumbnail(target_wh, target_wh)

src/tests/pre_messages/additional_text.rs

@@ -34,7 +34,7 @@ async fn test_additional_text_on_different_viewtypes() -> Result<()> {
     let (pre_message, _, _) = send_large_image_message(alice, a_group_id).await?;
     let msg = bob.recv_msg(&pre_message).await;
     assert_eq!(msg.text, "test".to_owned());
-    assert_eq!(msg.get_text(), "test [Image – 146.12 KiB]".to_owned());
+    assert_eq!(msg.get_text(), "test [Image – 137.04 KiB]".to_owned());
 
     Ok(())
 }

src/tests/pre_messages/receiving.rs

@@ -394,7 +394,7 @@ async fn test_receive_pre_message_image() -> Result<()> {
     // test that metadata is correctly returned by methods
     assert_eq!(msg.get_post_message_viewtype(), Some(Viewtype::Image));
     // recoded image dimensions
-    assert_eq!(msg.get_filebytes(bob).await?, Some(149632));
+    assert_eq!(msg.get_filebytes(bob).await?, Some(140327));
     assert_eq!(msg.get_height(), 1280);
     assert_eq!(msg.get_width(), 720);