deltachat/
blob.rs

1//! # Blob directory management.
2
3use std::cmp::{max, min};
4use std::io::{Cursor, Seek};
5use std::iter::FusedIterator;
6use std::mem;
7use std::path::{Path, PathBuf};
8
9use anyhow::{Context as _, Result, ensure, format_err};
10use base64::Engine as _;
11use futures::StreamExt;
12use image::ImageReader;
13use image::{DynamicImage, GenericImage, GenericImageView, ImageFormat, Pixel, Rgba};
14use image::{codecs::jpeg::JpegEncoder, metadata::Orientation};
15use num_traits::{FromPrimitive, cast};
16use tokio::{fs, task};
17use tokio_stream::wrappers::ReadDirStream;
18
19use crate::config::Config;
20use crate::constants::{self, MediaQuality};
21use crate::context::Context;
22use crate::events::EventType;
23use crate::log::{LogExt, warn};
24use crate::message::Viewtype;
25use crate::tools::sanitize_filename;
26
27/// Represents a file in the blob directory.
28///
29/// The object has a name, which will always be valid UTF-8.  Having a
30/// blob object does not imply the respective file exists, however
31/// when using one of the `create*()` methods a unique file is
32/// created.
33#[derive(Debug, Clone, PartialEq, Eq)]
34pub struct BlobObject<'a> {
35    blobdir: &'a Path,
36
37    /// The name of the file on the disc.
38    /// Note that this is NOT the user-visible filename,
39    /// which is only stored in Param::Filename on the message.
40    name: String,
41}
42
43#[derive(Debug, Clone)]
44enum ImageOutputFormat {
45    Png,
46    Jpeg { quality: u8 },
47}
48
49impl<'a> BlobObject<'a> {
50    /// Creates a blob object by copying or renaming an existing file.
51    /// If the source file is already in the blobdir, it will be renamed,
52    /// otherwise it will be copied to the blobdir first.
53    ///
54    /// In order to deduplicate files that contain the same data,
55    /// the file will be named `<hash>.<extension>`, e.g. `ce940175885d7b78f7b7e9f1396611f.jpg`.
56    /// The `original_name` param is only used to get the extension.
57    ///
58    /// This is done in a in way which avoids race-conditions when multiple files are
59    /// concurrently created.
60    pub fn create_and_deduplicate(
61        context: &'a Context,
62        src: &Path,
63        original_name: &Path,
64    ) -> Result<BlobObject<'a>> {
65        // `create_and_deduplicate{_from_bytes}()` do blocking I/O, but can still be called
66        // from an async context thanks to `block_in_place()`.
67        // Tokio's "async" I/O functions are also just thin wrappers around the blocking I/O syscalls,
68        // so we are doing essentially the same here.
69        task::block_in_place(|| {
70            let temp_path;
71            let src_in_blobdir: &Path;
72            let blobdir = context.get_blobdir();
73
74            if src.starts_with(blobdir) {
75                src_in_blobdir = src;
76            } else {
77                info!(
78                    context,
79                    "Source file not in blobdir. Copying instead of moving in order to prevent moving a file that was still needed."
80                );
81                temp_path = blobdir.join(format!("tmp-{}", rand::random::<u64>()));
82                if std::fs::copy(src, &temp_path).is_err() {
83                    // Maybe the blobdir didn't exist
84                    std::fs::create_dir_all(blobdir).log_err(context).ok();
85                    std::fs::copy(src, &temp_path).context("Copying new blobfile failed")?;
86                };
87                src_in_blobdir = &temp_path;
88            }
89
90            let hash = file_hash(src_in_blobdir)?.to_hex();
91            let hash = hash.as_str();
92            let hash = hash.get(0..31).unwrap_or(hash);
93            let new_file =
94                if let Some(extension) = original_name.extension().filter(|e| e.len() <= 32) {
95                    let extension = extension.to_string_lossy().to_lowercase();
96                    let extension = sanitize_filename(&extension);
97                    format!("$BLOBDIR/{hash}.{extension}")
98                } else {
99                    format!("$BLOBDIR/{hash}")
100                };
101
102            let blob = BlobObject {
103                blobdir,
104                name: new_file,
105            };
106            let new_path = blob.to_abs_path();
107
108            // This will also replace an already-existing file.
109            // Renaming is atomic, so this will avoid race conditions.
110            std::fs::rename(src_in_blobdir, &new_path)?;
111
112            context.emit_event(EventType::NewBlobFile(blob.as_name().to_string()));
113            Ok(blob)
114        })
115    }
116
117    /// Creates a new blob object with the file contents in `data`.
118    /// In order to deduplicate files that contain the same data,
119    /// the file will be named `<hash>.<extension>`, e.g. `ce940175885d7b78f7b7e9f1396611f.jpg`.
120    /// The `original_name` param is only used to get the extension.
121    ///
122    /// The `data` will be written into the file without race-conditions.
123    ///
124    /// This function does blocking I/O, but it can still be called from an async context
125    /// because `block_in_place()` is used to leave the async runtime if necessary.
126    pub fn create_and_deduplicate_from_bytes(
127        context: &'a Context,
128        data: &[u8],
129        original_name: &str,
130    ) -> Result<BlobObject<'a>> {
131        task::block_in_place(|| {
132            let blobdir = context.get_blobdir();
133            let temp_path = blobdir.join(format!("tmp-{}", rand::random::<u64>()));
134            if std::fs::write(&temp_path, data).is_err() {
135                // Maybe the blobdir didn't exist
136                std::fs::create_dir_all(blobdir).log_err(context).ok();
137                std::fs::write(&temp_path, data).context("writing new blobfile failed")?;
138            };
139
140            BlobObject::create_and_deduplicate(context, &temp_path, Path::new(original_name))
141        })
142    }
143
144    /// Returns a [BlobObject] for an existing blob from a path.
145    ///
146    /// The path must designate a file directly in the blobdir and
147    /// must use a valid blob name.  That is after sanitisation the
148    /// name must still be the same, that means it must be valid UTF-8
149    /// and not have any special characters in it.
150    pub fn from_path(context: &'a Context, path: &Path) -> Result<BlobObject<'a>> {
151        let rel_path = path
152            .strip_prefix(context.get_blobdir())
153            .with_context(|| format!("wrong blobdir: {}", path.display()))?;
154        let name = rel_path.to_str().context("wrong name")?;
155        if !BlobObject::is_acceptible_blob_name(name) {
156            return Err(format_err!("bad blob name: {}", rel_path.display()));
157        }
158        BlobObject::from_name(context, name)
159    }
160
161    /// Returns a [BlobObject] for an existing blob.
162    ///
163    /// The `name` may optionally be prefixed with the `$BLOBDIR/`
164    /// prefixed, as returned by [BlobObject::as_name].  This is how
165    /// you want to create a [BlobObject] for a filename read from the
166    /// database.
167    pub fn from_name(context: &'a Context, name: &str) -> Result<BlobObject<'a>> {
168        let name = match name.starts_with("$BLOBDIR/") {
169            true => name.splitn(2, '/').last().unwrap(),
170            false => name,
171        };
172        if !BlobObject::is_acceptible_blob_name(name) {
173            return Err(format_err!("not an acceptable blob name: {name}"));
174        }
175        Ok(BlobObject {
176            blobdir: context.get_blobdir(),
177            name: format!("$BLOBDIR/{name}"),
178        })
179    }
180
181    /// Returns the absolute path to the blob in the filesystem.
182    pub fn to_abs_path(&self) -> PathBuf {
183        let fname = Path::new(&self.name).strip_prefix("$BLOBDIR/").unwrap();
184        self.blobdir.join(fname)
185    }
186
187    /// Returns the blob name, as stored in the database.
188    ///
189    /// This returns the blob in the `$BLOBDIR/<name>` format used in
190    /// the database.  Do not use this unless you're about to store
191    /// this string in the database or [Params].  Eventually even
192    /// those conversions should be handled by the type system.
193    ///
194    /// Note that this is NOT the user-visible filename,
195    /// which is only stored in Param::Filename on the message.
196    ///
197    #[allow(rustdoc::private_intra_doc_links)]
198    /// [Params]: crate::param::Params
199    pub fn as_name(&self) -> &str {
200        &self.name
201    }
202
203    /// Returns the extension of the blob.
204    ///
205    /// If a blob's filename has an extension, it is always guaranteed
206    /// to be lowercase.
207    pub fn suffix(&self) -> Option<&str> {
208        let ext = self.name.rsplit('.').next();
209        if ext == Some(&self.name) { None } else { ext }
210    }
211
212    /// Checks whether a name is a valid blob name.
213    ///
214    /// This is slightly less strict than stanitise_name, presumably
215    /// someone already created a file with such a name so we just
216    /// ensure it's not actually a path in disguise.
217    ///
218    /// Acceptible blob name always have to be valid utf-8.
219    fn is_acceptible_blob_name(name: &str) -> bool {
220        if name.find('/').is_some() {
221            return false;
222        }
223        if name.find('\\').is_some() {
224            return false;
225        }
226        if name.find('\0').is_some() {
227            return false;
228        }
229        true
230    }
231
232    /// Returns path to the stored Base64-decoded blob.
233    ///
234    /// If `data` represents an image of known format, this adds the corresponding extension.
235    ///
236    /// Even though this function is not async, it's OK to call it from an async context.
237    ///
238    /// Returns an error if there is an I/O problem,
239    /// but in case of a failure to decode base64 returns `Ok(None)`.
240    pub(crate) fn store_from_base64(context: &Context, data: &str) -> Result<Option<String>> {
241        let Ok(buf) = base64::engine::general_purpose::STANDARD.decode(data) else {
242            return Ok(None);
243        };
244        let name = if let Ok(format) = image::guess_format(&buf) {
245            if let Some(ext) = format.extensions_str().first() {
246                format!("file.{ext}")
247            } else {
248                String::new()
249            }
250        } else {
251            String::new()
252        };
253        let blob = BlobObject::create_and_deduplicate_from_bytes(context, &buf, &name)?;
254        Ok(Some(blob.as_name().to_string()))
255    }
256
257    /// Recode image to avatar size.
258    pub async fn recode_to_avatar_size(&mut self, context: &Context) -> Result<()> {
259        let (max_wh, max_bytes) =
260            match MediaQuality::from_i32(context.get_config_int(Config::MediaQuality).await?)
261                .unwrap_or_default()
262            {
263                MediaQuality::Balanced => (
264                    constants::BALANCED_AVATAR_SIZE,
265                    constants::BALANCED_AVATAR_BYTES,
266                ),
267                MediaQuality::Worse => {
268                    (constants::WORSE_AVATAR_SIZE, constants::WORSE_AVATAR_BYTES)
269                }
270            };
271
272        let viewtype = &mut Viewtype::Image;
273        let is_avatar = true;
274        self.check_or_recode_to_size(
275            context, None, // The name of an avatar doesn't matter
276            viewtype, max_wh, max_bytes, is_avatar,
277        )?;
278
279        Ok(())
280    }
281
282    /// Checks or recodes an image pointed by the [BlobObject] so that it fits into limits on the
283    /// image width, height and file size specified by the config.
284    ///
285    /// Recoding is only done for [`Viewtype::Image`]. For [`Viewtype::File`], if it's a correct
286    /// image, `*viewtype` is set to [`Viewtype::Image`].
287    pub async fn check_or_recode_image(
288        &mut self,
289        context: &Context,
290        name: Option<String>,
291        viewtype: &mut Viewtype,
292    ) -> Result<String> {
293        let (max_wh, max_bytes) =
294            match MediaQuality::from_i32(context.get_config_int(Config::MediaQuality).await?)
295                .unwrap_or_default()
296            {
297                MediaQuality::Balanced => (
298                    constants::BALANCED_IMAGE_SIZE,
299                    constants::BALANCED_IMAGE_BYTES,
300                ),
301                MediaQuality::Worse => (constants::WORSE_IMAGE_SIZE, constants::WORSE_IMAGE_BYTES),
302            };
303        let is_avatar = false;
304        self.check_or_recode_to_size(context, name, viewtype, max_wh, max_bytes, is_avatar)
305    }
306
307    /// Checks or recodes the image so that it fits into limits on width/height and/or byte size.
308    ///
309    /// If `!is_avatar`, then if `max_bytes` is exceeded, reduces the image to `max_wh` and proceeds
310    /// with the result (even if `max_bytes` is still exceeded).
311    ///
312    /// If `is_avatar`, the resolution will be reduced in a loop until the image fits `max_bytes`.
313    ///
314    /// This modifies the blob object in-place.
315    ///
316    /// Additionally, if you pass the user-visible filename as `name`
317    /// then the updated user-visible filename will be returned;
318    /// this may be necessary because the format may be changed to JPG,
319    /// i.e. "image.png" -> "image.jpg".
320    #[expect(clippy::arithmetic_side_effects)]
321    fn check_or_recode_to_size(
322        &mut self,
323        context: &Context,
324        name: Option<String>,
325        viewtype: &mut Viewtype,
326        max_wh: u32,
327        max_bytes: usize,
328        is_avatar: bool,
329    ) -> Result<String> {
330        // Add white background only to avatars to spare the CPU.
331        let mut add_white_bg = is_avatar;
332        let mut no_exif = false;
333        let no_exif_ref = &mut no_exif;
334        let mut name = name.unwrap_or_else(|| self.name.clone());
335        let original_name = name.clone();
336        let vt = &mut *viewtype;
337        let res: Result<String> = tokio::task::block_in_place(move || {
338            let mut file = std::fs::File::open(self.to_abs_path())?;
339            let (nr_bytes, exif) = image_metadata(&file)?;
340            *no_exif_ref = exif.is_none();
341            // It's strange that BufReader modifies a file position while it takes a non-mut
342            // reference. Ok, just rewind it.
343            file.rewind()?;
344            let imgreader = ImageReader::new(std::io::BufReader::new(&file)).with_guessed_format();
345            let imgreader = match imgreader {
346                Ok(ir) => ir,
347                _ => {
348                    file.rewind()?;
349                    ImageReader::with_format(
350                        std::io::BufReader::new(&file),
351                        ImageFormat::from_path(self.to_abs_path())?,
352                    )
353                }
354            };
355            let fmt = imgreader.format().context("Unknown format")?;
356            if *vt == Viewtype::File {
357                *vt = Viewtype::Image;
358                return Ok(name);
359            }
360            let mut img = imgreader.decode().context("image decode failure")?;
361            let orientation = exif
362                .as_ref()
363                .map(|exif| exif_orientation(exif, context))
364                .unwrap_or(Orientation::NoTransforms);
365            let mut encoded = Vec::new();
366
367            if *vt == Viewtype::Sticker {
368                let x_max = img.width().saturating_sub(1);
369                let y_max = img.height().saturating_sub(1);
370                if !img.in_bounds(x_max, y_max)
371                    || !(img.get_pixel(0, 0).0[3] == 0
372                        || img.get_pixel(x_max, 0).0[3] == 0
373                        || img.get_pixel(0, y_max).0[3] == 0
374                        || img.get_pixel(x_max, y_max).0[3] == 0)
375                {
376                    *vt = Viewtype::Image;
377                } else {
378                    // Core doesn't auto-assign `Viewtype::Sticker` to messages and stickers coming
379                    // from UIs shouldn't contain sensitive Exif info.
380                    return Ok(name);
381                }
382            }
383            img.apply_orientation(orientation);
384
385            // max_wh is the maximum image width and height, i.e. the resolution-limit,
386            // as set by `Config::MediaQuality`.
387            let exceeds_wh = img.width() > max_wh || img.height() > max_wh;
388            let exceeds_max_bytes = nr_bytes > max_bytes as u64;
389
390            let jpeg_quality = 75;
391            let ofmt = match fmt {
392                ImageFormat::Png if !exceeds_max_bytes => ImageOutputFormat::Png,
393                ImageFormat::Jpeg => {
394                    add_white_bg = false;
395                    ImageOutputFormat::Jpeg {
396                        quality: jpeg_quality,
397                    }
398                }
399                _ => ImageOutputFormat::Jpeg {
400                    quality: jpeg_quality,
401                },
402            };
403            // We need to rewrite images with Exif to remove metadata such as location,
404            // camera model, etc.
405            //
406            // TODO: Fix lost animation and transparency when recoding using the `image` crate. And
407            // also `Viewtype::Gif` (maybe renamed to `Animation`) should be used for animated
408            // images.
409            let do_scale = exceeds_max_bytes
410                || is_avatar
411                    && (exceeds_wh
412                        || exif.is_some() && {
413                            if mem::take(&mut add_white_bg) {
414                                self::add_white_bg(&mut img);
415                            }
416                            encoded_img_exceeds_bytes(
417                                context,
418                                &img,
419                                ofmt.clone(),
420                                max_bytes,
421                                &mut encoded,
422                            )?
423                        });
424
425            if do_scale {
426                let longest_side_len = max(img.width(), img.height());
427
428                // target_wh will be used as the target-resolution for resizing the image,
429                // so that the longest sides of the image match the target-resolution.
430                let mut target_wh = if !is_avatar {
431                    let area_sqrt = (f64::from(img.width()) * f64::from(img.height())).sqrt();
432                    // Limit resolution to the number of pixels that fit within max_wh * max_wh,
433                    // so that the image-quality does not depend on the aspect-ratio.
434                    let mut resolution_limit: u32 = cast(
435                        (f64::from(longest_side_len) * (f64::from(max_wh) / area_sqrt)).floor(),
436                    )
437                    .unwrap_or(max_wh);
438                    // Align at least one dimension of the resampled image to a multiple of 8 pixels,
439                    // to have fewer partially used JPEG-blocks (which represent 8x8 pixels each).
440                    if resolution_limit < longest_side_len && resolution_limit > 8 {
441                        while !resolution_limit.is_multiple_of(8) {
442                            resolution_limit -= 1
443                        }
444                    }
445                    resolution_limit
446                } else {
447                    max_wh
448                };
449
450                target_wh = min(target_wh, longest_side_len);
451
452                // For images in JPEG-format, 65535 pixels is the maximum resolution per dimension.
453                target_wh = min(target_wh, 65535);
454
455                loop {
456                    if mem::take(&mut add_white_bg) {
457                        self::add_white_bg(&mut img);
458                    }
459
460                    // resize() results in often slightly better quality,
461                    // however, comes at high price of being 4+ times slower than thumbnail().
462                    // for a typical camera image that is sent, this may be a change from "instant" (500ms) to "long time waiting" (3s).
463                    // as we do not have recoding in background while chat has already a preview,
464                    // we vote for speed.
465                    // exception is the avatar image: this is far more often sent than recoded,
466                    // usually has less pixels by cropping, UI that needs to wait anyways,
467                    // and also benefits from slightly better (5%) encoding of Triangle-filtered images.
468                    let new_img = if is_avatar {
469                        img.resize(target_wh, target_wh, image::imageops::FilterType::Triangle)
470                    } else {
471                        img.thumbnail(target_wh, target_wh)
472                    };
473
474                    if encoded_img_exceeds_bytes(
475                        context,
476                        &new_img,
477                        ofmt.clone(),
478                        max_bytes,
479                        &mut encoded,
480                    )? && is_avatar
481                    {
482                        if target_wh < 20 {
483                            return Err(format_err!(
484                                "Failed to scale image to below {max_bytes}B.",
485                            ));
486                        }
487
488                        target_wh = target_wh * 7 / 8;
489                    } else {
490                        info!(
491                            context,
492                            "Final scaled-down image size: {}B ({}px).",
493                            encoded.len(),
494                            target_wh
495                        );
496                        break;
497                    }
498                }
499            }
500
501            if do_scale || exif.is_some() {
502                // The file format is JPEG/PNG now, we may have to change the file extension
503                if !matches!(fmt, ImageFormat::Jpeg)
504                    && matches!(ofmt, ImageOutputFormat::Jpeg { .. })
505                {
506                    name = Path::new(&name)
507                        .with_extension("jpg")
508                        .to_string_lossy()
509                        .into_owned();
510                }
511
512                if encoded.is_empty() {
513                    if mem::take(&mut add_white_bg) {
514                        self::add_white_bg(&mut img);
515                    }
516                    encode_img(&img, ofmt, &mut encoded)?;
517                }
518
519                self.name = BlobObject::create_and_deduplicate_from_bytes(context, &encoded, &name)
520                    .context("failed to write recoded blob to file")?
521                    .name;
522            }
523
524            Ok(name)
525        });
526        match res {
527            Ok(_) => res,
528            Err(err) => {
529                if !is_avatar && no_exif {
530                    error!(
531                        context,
532                        "Cannot check/recode image, using original data: {err:#}.",
533                    );
534                    *viewtype = Viewtype::File;
535                    Ok(original_name)
536                } else {
537                    Err(err)
538                }
539            }
540        }
541    }
542}
543
544fn file_hash(src: &Path) -> Result<blake3::Hash> {
545    ensure!(
546        !src.starts_with("$BLOBDIR/"),
547        "Use `get_abs_path()` to get the absolute path of the blobfile"
548    );
549    let mut hasher = blake3::Hasher::new();
550    let mut src_file = std::fs::File::open(src)
551        .with_context(|| format!("Failed to open file {}", src.display()))?;
552    hasher
553        .update_reader(&mut src_file)
554        .context("update_reader")?;
555    let hash = hasher.finalize();
556    Ok(hash)
557}
558
559/// Returns image file size and Exif.
560fn image_metadata(file: &std::fs::File) -> Result<(u64, Option<exif::Exif>)> {
561    let len = file.metadata()?.len();
562    let mut bufreader = std::io::BufReader::new(file);
563    let exif = exif::Reader::new()
564        .continue_on_error(true)
565        .read_from_container(&mut bufreader)
566        .or_else(|e| e.distill_partial_result(|_errors| {}))
567        .ok();
568    Ok((len, exif))
569}
570
571fn exif_orientation(exif: &exif::Exif, context: &Context) -> Orientation {
572    if let Some(orientation) = exif.get_field(exif::Tag::Orientation, exif::In::PRIMARY)
573        && let Some(val) = orientation.value.get_uint(0)
574        && let Ok(val) = TryInto::<u8>::try_into(val)
575    {
576        return Orientation::from_exif(val).unwrap_or({
577            warn!(context, "Exif orientation value ignored: {val:?}.");
578            Orientation::NoTransforms
579        });
580    }
581    Orientation::NoTransforms
582}
583
584/// All files in the blobdir.
585///
586/// This exists so we can have a [`BlobDirIter`] which needs something to own the data of
587/// it's `&Path`.  Use [`BlobDirContents::iter`] to create the iterator.
588///
589/// Additionally pre-allocating this means we get a length for progress report.
590pub(crate) struct BlobDirContents<'a> {
591    inner: Vec<PathBuf>,
592    context: &'a Context,
593}
594
595impl<'a> BlobDirContents<'a> {
596    pub(crate) async fn new(context: &'a Context) -> Result<BlobDirContents<'a>> {
597        let readdir = fs::read_dir(context.get_blobdir()).await?;
598        let inner = ReadDirStream::new(readdir)
599            .filter_map(|entry| async move {
600                match entry {
601                    Ok(entry) => Some(entry),
602                    Err(err) => {
603                        error!(context, "Failed to read blob file: {err}.");
604                        None
605                    }
606                }
607            })
608            .filter_map(|entry| async move {
609                match entry.file_type().await.ok()?.is_file() {
610                    true => Some(entry.path()),
611                    false => {
612                        warn!(
613                            context,
614                            "Export: Found blob dir entry {} that is not a file, ignoring.",
615                            entry.path().display()
616                        );
617                        None
618                    }
619                }
620            })
621            .collect()
622            .await;
623        Ok(Self { inner, context })
624    }
625
626    pub(crate) fn iter(&self) -> BlobDirIter<'_> {
627        BlobDirIter::new(self.context, self.inner.iter())
628    }
629}
630
631/// A iterator over all the [`BlobObject`]s in the blobdir.
632pub(crate) struct BlobDirIter<'a> {
633    iter: std::slice::Iter<'a, PathBuf>,
634    context: &'a Context,
635}
636
637impl<'a> BlobDirIter<'a> {
638    fn new(context: &'a Context, iter: std::slice::Iter<'a, PathBuf>) -> BlobDirIter<'a> {
639        Self { iter, context }
640    }
641}
642
643impl<'a> Iterator for BlobDirIter<'a> {
644    type Item = BlobObject<'a>;
645
646    fn next(&mut self) -> Option<Self::Item> {
647        for path in self.iter.by_ref() {
648            // In theory this can error but we'd have corrupted filenames in the blobdir, so
649            // silently skipping them is fine.
650            match BlobObject::from_path(self.context, path) {
651                Ok(blob) => return Some(blob),
652                Err(err) => warn!(self.context, "{err}"),
653            }
654        }
655        None
656    }
657}
658
659impl FusedIterator for BlobDirIter<'_> {}
660
661fn encode_img(
662    img: &DynamicImage,
663    fmt: ImageOutputFormat,
664    encoded: &mut Vec<u8>,
665) -> anyhow::Result<()> {
666    encoded.clear();
667    let mut buf = Cursor::new(encoded);
668    match fmt {
669        ImageOutputFormat::Png => img.write_to(&mut buf, ImageFormat::Png)?,
670        ImageOutputFormat::Jpeg { quality } => {
671            let encoder = JpegEncoder::new_with_quality(&mut buf, quality);
672            // Convert image into RGB8 to avoid the error
673            // "The encoder or decoder for Jpeg does not support the color type Rgba8"
674            // (<https://github.com/image-rs/image/issues/2211>).
675            img.clone().into_rgb8().write_with_encoder(encoder)?;
676        }
677    }
678    Ok(())
679}
680
681fn encoded_img_exceeds_bytes(
682    context: &Context,
683    img: &DynamicImage,
684    fmt: ImageOutputFormat,
685    max_bytes: usize,
686    encoded: &mut Vec<u8>,
687) -> anyhow::Result<bool> {
688    encode_img(img, fmt, encoded)?;
689    if encoded.len() > max_bytes {
690        info!(
691            context,
692            "Image size {}B ({}x{}px) exceeds {}B, need to scale down.",
693            encoded.len(),
694            img.width(),
695            img.height(),
696            max_bytes,
697        );
698        return Ok(true);
699    }
700    Ok(false)
701}
702
703/// Removes transparency from an image using a white background.
704fn add_white_bg(img: &mut DynamicImage) {
705    for y in 0..img.height() {
706        for x in 0..img.width() {
707            let mut p = Rgba([255u8, 255, 255, 255]);
708            p.blend(&img.get_pixel(x, y));
709            img.put_pixel(x, y, p);
710        }
711    }
712}
713
714#[cfg(test)]
715mod blob_tests;
deltachat/blob.rs

deltachat/
blob.rs
