Convert avatars to WEBP during upload #10708

23ae939ef3/modules/avatar/avatar.go (L47-L86)

@zeripath commented on GitHub (May 10, 2023):

Squaring

hmm... as far as I can see the squaring process is unrelated to the choice of format.

If you take a look at the code for Prepare:

The squaring happens because of:

23ae939ef3/modules/avatar/avatar.go (L64-L84)

Scaling up

Similarly the increase in size occurs because of the call to resize.

23ae939ef3/modules/avatar/avatar.go (L84)

Exporting as png

Exporting as png appears to occur in two places:

23ae939ef3/services/repository/avatar.go (L50)

23ae939ef3/services/user/user.go (L265)

These would both need to change to use webp.

We could probably change the code in generateRandomAvatar to use webp too:

23ae939ef3/models/repo/avatar.go (L51)

(It does not look like:

23ae939ef3/tests/integration/user_avatar_test.go (L55)

would need to change)

Animation

Unfortunately the golang x/image/png library does not support animation. There has been a feature request:

https://github.com/golang/go/issues/53364

but no action has been taken.

There are other libraries that use cgo to bind to libwebp and should provide animation support but we would need to change from using image.Decode to some other function and it would need to detect if there is animation present.

Gitea at present will probably just take the first frame of an animated gif. So I think animation is going to take a bit of work.

Issues with Scaling and Resize

As far as I can see resize.Resize (and in some cases cutter.Crop) will convert the avatar into image.RGBA which decompresses the image and may make it quite large - taking up memory. This does not seem quite ideal.

So I think what we need to do is to rethink about what the avatar code is supposed to do.

Should we be doing any of this resizing and cropping at all? Should we simply be enforcing our max height and width and storing like that?
If we do resizing/cropping should we only resize/crop when the image is bigger than the avatar size?
Should we store as webp?
Should we look at being able to store animations?

@zeripath commented on GitHub (May 10, 2023): ## Squaring hmm... as far as I can see the squaring process is unrelated to the choice of format. If you take a look at the code for Prepare: https://github.com/go-gitea/gitea/blob/23ae939ef3ef03848038372de21490725855b5f9/modules/avatar/avatar.go#L47-L86 The squaring happens because of: https://github.com/go-gitea/gitea/blob/23ae939ef3ef03848038372de21490725855b5f9/modules/avatar/avatar.go#L64-L84 ## Scaling up Similarly the increase in size occurs because of the call to resize. https://github.com/go-gitea/gitea/blob/23ae939ef3ef03848038372de21490725855b5f9/modules/avatar/avatar.go#L84 ## Exporting as png Exporting as png appears to occur in two places: https://github.com/go-gitea/gitea/blob/23ae939ef3ef03848038372de21490725855b5f9/services/repository/avatar.go#L50 https://github.com/go-gitea/gitea/blob/23ae939ef3ef03848038372de21490725855b5f9/services/user/user.go#L265 These would both need to change to use webp. We could probably change the code in generateRandomAvatar to use webp too: https://github.com/go-gitea/gitea/blob/23ae939ef3ef03848038372de21490725855b5f9/models/repo/avatar.go#L51 (It does not look like: https://github.com/go-gitea/gitea/blob/23ae939ef3ef03848038372de21490725855b5f9/tests/integration/user_avatar_test.go#L55 would need to change) ## Animation Unfortunately the golang x/image/png library does not support animation. There has been a feature request: https://github.com/golang/go/issues/53364 but no action has been taken. There are other libraries that use cgo to bind to libwebp and should provide animation support but we would need to change from using image.Decode to some other function and it would need to detect if there is animation present. Gitea at present will probably just take the first frame of an animated gif. So I think animation is going to take a bit of work. ## Issues with Scaling and Resize As far as I can see `resize.Resize` (and in some cases `cutter.Crop`) will convert the avatar into `image.RGBA` which decompresses the image and may make it quite large - taking up memory. This does not seem quite ideal. ## So I think what we need to do is to rethink about what the avatar code is supposed to do. 1. Should we be doing any of this resizing and cropping at all? Should we simply be enforcing our max height and width and storing like that? 2. If we do resizing/cropping should we only resize/crop when the image is bigger than the avatar size? 3. Should we store as webp? 4. Should we look at being able to store animations?

GiteaMirror commented

@silverwind commented on GitHub (May 10, 2023):

Should we be doing any of this resizing and cropping at all? Should we simply be enforcing our max height and width and storing like that?

I don't think we need to square or crop. Browser rendering can and should take care of letterboxing the image. We can certainly ensure this in our rendering. If other sites that embed gitea avatars assume our avatars are always square, they will need to fix it themselves.

Should we store as webp?

Yes, browser support is good enough that we can store a well-compressed webp.

Should we look at being able to store animations?

Animations are nice to have, but not a requirement for me. Happy to defer this to https://github.com/golang/go/issues/53364.

@silverwind commented on GitHub (May 10, 2023): > Should we be doing any of this resizing and cropping at all? Should we simply be enforcing our max height and width and storing like that? I don't think we need to square or crop. [Browser rendering](https://developer.mozilla.org/en-US/docs/Web/CSS/object-fit) can and should take care of letterboxing the image. We can certainly ensure this in our rendering. If other sites that embed gitea avatars assume our avatars are always square, they will need to fix it themselves. > Should we store as webp? Yes, browser support is good enough that we can store a well-compressed webp. > Should we look at being able to store animations? Animations are nice to have, but not a requirement for me. Happy to defer this to https://github.com/golang/go/issues/53364.

GiteaMirror commented

@sosasees commented on GitHub (May 10, 2023):

Should we look at being able to store animations?

this is not needed.
animated avatars can be fun on a casual website,
but on a serious website like Gitea they would be just annoying.

@sosasees commented on GitHub (May 10, 2023): > Should we look at being able to store animations? this is not needed. animated avatars can be fun on a casual website, but on a serious website like Gitea they would be just annoying.

GiteaMirror commented

@silverwind commented on GitHub (May 10, 2023):

Should we be doing any of this resizing

I guess resizing could be considered above a certain pixel count. Let's say a lazy user directly uploads a photo taken from a digital camera which is let's say 50 Megapixels. We'd definitely want to downsize that to not destroy rendering performance and bandwidth consumption for other users.

I would say we could use a Megapixel constant above which to downsize the image to something more suitable for web consumption. Maybe make it 1 Megapixel, which is a 1000x1000 image that is suitable for fine rendering on 4dppx devices down to 250px width/height, which I think is close to avatars rendered on user pages.

@silverwind commented on GitHub (May 10, 2023): > Should we be doing any of this resizing I guess resizing could be considered above a certain pixel count. Let's say a lazy user directly uploads a photo taken from a digital camera which is let's say 50 Megapixels. We'd definitely want to downsize that to not destroy rendering performance and bandwidth consumption for other users. I would say we could use a Megapixel constant above which to downsize the image to something more suitable for web consumption. Maybe make it 1 Megapixel, which is a 1000x1000 image that is suitable for fine rendering on 4dppx devices down to 250px width/height, which I think is close to avatars rendered on user pages.

GiteaMirror commented

@zeripath commented on GitHub (May 10, 2023):

OK looking at encoding directly to webp we can't use x/image/webp and would need to use something that wraps the libwebp C library or write a PR to x/image/webp to do the encoding.

The first option I came across: https://github.com/kolesa-team/go-webp requires that I install libwebp-dev on my system - this would likely cause a significant issue with compiling on Windows.

PATCH for this option - would need changes to builders to install libwebp-dev though

diff --git a/go.mod b/go.mod
index 24765df18..e9e71a27e 100644
--- a/go.mod
+++ b/go.mod
@@ -218,6 +218,7 @@ require (
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/kevinburke/ssh_config v1.2.0 // indirect
 	github.com/klauspost/pgzip v1.2.6 // indirect
+	github.com/kolesa-team/go-webp v1.0.4 // indirect
 	github.com/kr/pretty v0.3.1 // indirect
 	github.com/kr/text v0.2.0 // indirect
 	github.com/libdns/libdns v0.2.1 // indirect
diff --git a/go.sum b/go.sum
index 62c01c690..269d46d55 100644
--- a/go.sum
+++ b/go.sum
@@ -792,6 +792,8 @@ github.com/klauspost/pgzip v1.2.5/go.mod h1:Ch1tH69qFZu15pkjo5kYi6mth2Zzwzt50oCQ
 github.com/klauspost/pgzip v1.2.6 h1:8RXeL5crjEUFnR2/Sn6GJNWtSQ3Dk8pq4CL3jvdDyjU=
 github.com/klauspost/pgzip v1.2.6/go.mod h1:Ch1tH69qFZu15pkjo5kYi6mth2Zzwzt50oCQKQE9RUs=
 github.com/kljensen/snowball v0.6.0/go.mod h1:27N7E8fVU5H68RlUmnWwZCfxgt4POBJfENGMvNRhldw=
+github.com/kolesa-team/go-webp v1.0.4 h1:wQvU4PLG/X7RS0vAeyhiivhLRoxfLVRlDq4I3frdxIQ=
+github.com/kolesa-team/go-webp v1.0.4/go.mod h1:oMvdivD6K+Q5qIIkVC2w4k2ZUnI1H+MyP7inwgWq9aA=
 github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/konsorten/go-windows-terminal-sequences v1.0.2/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ=
 github.com/kr/fs v0.1.0/go.mod h1:FFnZGqtBN9Gxj7eW1uZ42v5BccTP0vu6NEaFoC2HwRg=
@@ -1334,6 +1336,7 @@ golang.org/x/exp v0.0.0-20200207192155-f17229e696bd/go.mod h1:J/WKrq2StrnmMY6+EH
 golang.org/x/exp v0.0.0-20200224162631-6cc2880d07d6/go.mod h1:3jZMyOhIsHpP37uCMkUooju7aAi5cS1Q23tOzKc+0MU=
 golang.org/x/image v0.0.0-20190227222117-0694c2d4d067/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js=
 golang.org/x/image v0.0.0-20190802002840-cff245a6509b/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0=
+golang.org/x/image v0.0.0-20210628002857-a66eb6448b8d/go.mod h1:023OzeP/+EPmXeapQh35lcL3II3LrY8Ic+EFFKVhULM=
 golang.org/x/image v0.7.0 h1:gzS29xtG1J5ybQlv0PuyfE3nmc6R4qB73m6LUUmvFuw=
 golang.org/x/image v0.7.0/go.mod h1:nd/q4ef1AKKYl/4kft7g+6UyGbdiqWqTP1ZAbRoV7Rg=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
diff --git a/models/repo/avatar.go b/models/repo/avatar.go
index a76a94926..ac961989a 100644
--- a/models/repo/avatar.go
+++ b/models/repo/avatar.go
@@ -6,7 +6,6 @@ package repo
 import (
 	"context"
 	"fmt"
-	"image/png"
 	"io"
 	"net/url"
 	"strings"
@@ -16,6 +15,9 @@ import (
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/storage"
+
+	"github.com/kolesa-team/go-webp/encoder"
+	"github.com/kolesa-team/go-webp/webp"
 )
 
 // CustomAvatarRelativePath returns repository custom avatar file path.
@@ -48,7 +50,12 @@ func generateRandomAvatar(ctx context.Context, repo *Repository) error {
 	repo.Avatar = idToString
 
 	if err := storage.SaveFrom(storage.RepoAvatars, repo.CustomAvatarRelativePath(), func(w io.Writer) error {
-		if err := png.Encode(w, img); err != nil {
+		options, err := encoder.NewLossyEncoderOptions(encoder.PresetDefault, 75)
+		if err != nil {
+			log.Error("Unable to create encoder options: %v", err)
+			return err
+		}
+		if err := webp.Encode(w, img, options); err != nil {
 			log.Error("Encode: %v", err)
 		}
 		return err
diff --git a/services/repository/avatar.go b/services/repository/avatar.go
index 74e5de877..9c6dd777a 100644
--- a/services/repository/avatar.go
+++ b/services/repository/avatar.go
@@ -6,7 +6,6 @@ package repository
 import (
 	"context"
 	"fmt"
-	"image/png"
 	"io"
 	"strconv"
 	"strings"
@@ -16,6 +15,9 @@ import (
 	"code.gitea.io/gitea/modules/avatar"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/storage"
+
+	"github.com/kolesa-team/go-webp/encoder"
+	"github.com/kolesa-team/go-webp/webp"
 )
 
 // UploadAvatar saves custom avatar for repository.
@@ -47,7 +49,12 @@ func UploadAvatar(ctx context.Context, repo *repo_model.Repository, data []byte)
 	}
 
 	if err := storage.SaveFrom(storage.RepoAvatars, repo.CustomAvatarRelativePath(), func(w io.Writer) error {
-		if err := png.Encode(w, *m); err != nil {
+		options, err := encoder.NewLossyEncoderOptions(encoder.PresetDefault, 75)
+		if err != nil {
+			log.Error("Unable to create encoder options: %v", err)
+			return err
+		}
+		if err := webp.Encode(w, *m, options); err != nil {
 			log.Error("Encode: %v", err)
 		}
 		return err
diff --git a/services/user/user.go b/services/user/user.go
index d52a2f404..1b379c025 100644
--- a/services/user/user.go
+++ b/services/user/user.go
@@ -6,7 +6,6 @@ package user
 import (
 	"context"
 	"fmt"
-	"image/png"
 	"io"
 	"time"
 
@@ -25,6 +24,9 @@ import (
 	"code.gitea.io/gitea/modules/storage"
 	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/services/packages"
+
+	"github.com/kolesa-team/go-webp/encoder"
+	"github.com/kolesa-team/go-webp/webp"
 )
 
 // RenameUser renames a user
@@ -262,7 +264,12 @@ func UploadAvatar(u *user_model.User, data []byte) error {
 	}
 
 	if err := storage.SaveFrom(storage.Avatars, u.CustomAvatarRelativePath(), func(w io.Writer) error {
-		if err := png.Encode(w, *m); err != nil {
+		options, err := encoder.NewLossyEncoderOptions(encoder.PresetDefault, 75)
+		if err != nil {
+			log.Error("Unable to create encoder options: %v", err)
+			return err
+		}
+		if err := webp.Encode(w, *m, options); err != nil {
 			log.Error("Encode: %v", err)
 		}
 		return err

https://github.com/chai2010/webp appears to wholesale import the libwebp source - which should work but we'd have to keep on top of ensuring that it's up to date.

https://git.sr.ht/~jackmordaunt/go-libwebp is a Ccgo port of libwebp to go - which could work without cgo - however, the library is marked experimental so is questionable.

@zeripath commented on GitHub (May 10, 2023): OK looking at encoding directly to webp we can't use x/image/webp and would need to use something that wraps the libwebp C library or write a PR to x/image/webp to do the encoding. The first option I came across: https://github.com/kolesa-team/go-webp requires that I install libwebp-dev on my system - this would likely cause a significant issue with compiling on Windows. <details><summary>PATCH for this option - would need changes to builders to install libwebp-dev though</summary> ```patch diff --git a/go.mod b/go.mod index 24765df18..e9e71a27e 100644 --- a/go.mod +++ b/go.mod @@ -218,6 +218,7 @@ require ( github.com/josharian/intern v1.0.0 // indirect github.com/kevinburke/ssh_config v1.2.0 // indirect github.com/klauspost/pgzip v1.2.6 // indirect + github.com/kolesa-team/go-webp v1.0.4 // indirect github.com/kr/pretty v0.3.1 // indirect github.com/kr/text v0.2.0 // indirect github.com/libdns/libdns v0.2.1 // indirect diff --git a/go.sum b/go.sum index 62c01c690..269d46d55 100644 --- a/go.sum +++ b/go.sum @@ -792,6 +792,8 @@ github.com/klauspost/pgzip v1.2.5/go.mod h1:Ch1tH69qFZu15pkjo5kYi6mth2Zzwzt50oCQ github.com/klauspost/pgzip v1.2.6 h1:8RXeL5crjEUFnR2/Sn6GJNWtSQ3Dk8pq4CL3jvdDyjU= github.com/klauspost/pgzip v1.2.6/go.mod h1:Ch1tH69qFZu15pkjo5kYi6mth2Zzwzt50oCQKQE9RUs= github.com/kljensen/snowball v0.6.0/go.mod h1:27N7E8fVU5H68RlUmnWwZCfxgt4POBJfENGMvNRhldw= +github.com/kolesa-team/go-webp v1.0.4 h1:wQvU4PLG/X7RS0vAeyhiivhLRoxfLVRlDq4I3frdxIQ= +github.com/kolesa-team/go-webp v1.0.4/go.mod h1:oMvdivD6K+Q5qIIkVC2w4k2ZUnI1H+MyP7inwgWq9aA= github.com/konsorten/go-windows-terminal-sequences v1.0.1/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ= github.com/konsorten/go-windows-terminal-sequences v1.0.2/go.mod h1:T0+1ngSBFLxvqU3pZ+m/2kptfBszLMUkC4ZK/EgS/cQ= github.com/kr/fs v0.1.0/go.mod h1:FFnZGqtBN9Gxj7eW1uZ42v5BccTP0vu6NEaFoC2HwRg= @@ -1334,6 +1336,7 @@ golang.org/x/exp v0.0.0-20200207192155-f17229e696bd/go.mod h1:J/WKrq2StrnmMY6+EH golang.org/x/exp v0.0.0-20200224162631-6cc2880d07d6/go.mod h1:3jZMyOhIsHpP37uCMkUooju7aAi5cS1Q23tOzKc+0MU= golang.org/x/image v0.0.0-20190227222117-0694c2d4d067/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js= golang.org/x/image v0.0.0-20190802002840-cff245a6509b/go.mod h1:FeLwcggjj3mMvU+oOTbSwawSJRM1uh48EjtB4UJZlP0= +golang.org/x/image v0.0.0-20210628002857-a66eb6448b8d/go.mod h1:023OzeP/+EPmXeapQh35lcL3II3LrY8Ic+EFFKVhULM= golang.org/x/image v0.7.0 h1:gzS29xtG1J5ybQlv0PuyfE3nmc6R4qB73m6LUUmvFuw= golang.org/x/image v0.7.0/go.mod h1:nd/q4ef1AKKYl/4kft7g+6UyGbdiqWqTP1ZAbRoV7Rg= golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE= diff --git a/models/repo/avatar.go b/models/repo/avatar.go index a76a94926..ac961989a 100644 --- a/models/repo/avatar.go +++ b/models/repo/avatar.go @@ -6,7 +6,6 @@ package repo import ( "context" "fmt" - "image/png" "io" "net/url" "strings" @@ -16,6 +15,9 @@ import ( "code.gitea.io/gitea/modules/log" "code.gitea.io/gitea/modules/setting" "code.gitea.io/gitea/modules/storage" + + "github.com/kolesa-team/go-webp/encoder" + "github.com/kolesa-team/go-webp/webp" ) // CustomAvatarRelativePath returns repository custom avatar file path. @@ -48,7 +50,12 @@ func generateRandomAvatar(ctx context.Context, repo *Repository) error { repo.Avatar = idToString if err := storage.SaveFrom(storage.RepoAvatars, repo.CustomAvatarRelativePath(), func(w io.Writer) error { - if err := png.Encode(w, img); err != nil { + options, err := encoder.NewLossyEncoderOptions(encoder.PresetDefault, 75) + if err != nil { + log.Error("Unable to create encoder options: %v", err) + return err + } + if err := webp.Encode(w, img, options); err != nil { log.Error("Encode: %v", err) } return err diff --git a/services/repository/avatar.go b/services/repository/avatar.go index 74e5de877..9c6dd777a 100644 --- a/services/repository/avatar.go +++ b/services/repository/avatar.go @@ -6,7 +6,6 @@ package repository import ( "context" "fmt" - "image/png" "io" "strconv" "strings" @@ -16,6 +15,9 @@ import ( "code.gitea.io/gitea/modules/avatar" "code.gitea.io/gitea/modules/log" "code.gitea.io/gitea/modules/storage" + + "github.com/kolesa-team/go-webp/encoder" + "github.com/kolesa-team/go-webp/webp" ) // UploadAvatar saves custom avatar for repository. @@ -47,7 +49,12 @@ func UploadAvatar(ctx context.Context, repo *repo_model.Repository, data []byte) } if err := storage.SaveFrom(storage.RepoAvatars, repo.CustomAvatarRelativePath(), func(w io.Writer) error { - if err := png.Encode(w, *m); err != nil { + options, err := encoder.NewLossyEncoderOptions(encoder.PresetDefault, 75) + if err != nil { + log.Error("Unable to create encoder options: %v", err) + return err + } + if err := webp.Encode(w, *m, options); err != nil { log.Error("Encode: %v", err) } return err diff --git a/services/user/user.go b/services/user/user.go index d52a2f404..1b379c025 100644 --- a/services/user/user.go +++ b/services/user/user.go @@ -6,7 +6,6 @@ package user import ( "context" "fmt" - "image/png" "io" "time" @@ -25,6 +24,9 @@ import ( "code.gitea.io/gitea/modules/storage" "code.gitea.io/gitea/modules/util" "code.gitea.io/gitea/services/packages" + + "github.com/kolesa-team/go-webp/encoder" + "github.com/kolesa-team/go-webp/webp" ) // RenameUser renames a user @@ -262,7 +264,12 @@ func UploadAvatar(u *user_model.User, data []byte) error { } if err := storage.SaveFrom(storage.Avatars, u.CustomAvatarRelativePath(), func(w io.Writer) error { - if err := png.Encode(w, *m); err != nil { + options, err := encoder.NewLossyEncoderOptions(encoder.PresetDefault, 75) + if err != nil { + log.Error("Unable to create encoder options: %v", err) + return err + } + if err := webp.Encode(w, *m, options); err != nil { log.Error("Encode: %v", err) } return err ``` </details> https://github.com/chai2010/webp appears to wholesale import the libwebp source - which should work but we'd have to keep on top of ensuring that it's up to date. https://git.sr.ht/~jackmordaunt/go-libwebp is a Ccgo port of libwebp to go - which could work without cgo - however, the library is marked experimental so is questionable.

GiteaMirror commented

@silverwind commented on GitHub (May 10, 2023):

https://github.com/chai2010/webp sounds like the best bet to me, but it still needs CGO, right? I thought we could get rid of CGO eventually, so I doubt that adding a new CGO dependency will be worth it.

I guess as a first step, we can go and alter the resizing/cropping mechanism as discussed while still outputting well compressed PNGs, which in turn would solve https://github.com/go-gitea/gitea/issues/8972.

@silverwind commented on GitHub (May 10, 2023): https://github.com/chai2010/webp sounds like the best bet to me, but it still needs CGO, right? I thought we could get rid of CGO eventually, so I doubt that adding a new CGO dependency will be worth it. I guess as a first step, we can go and alter the resizing/cropping mechanism as discussed while still outputting well compressed PNGs, which in turn would solve https://github.com/go-gitea/gitea/issues/8972.

GiteaMirror commented

@wxiaoguang commented on GitHub (May 10, 2023):

I guess introducing a full featured webp/png converter would bloat Gitea not just a little ....

@wxiaoguang commented on GitHub (May 10, 2023): I guess introducing a full featured webp/png converter would bloat Gitea not just a little ....

GiteaMirror commented

@silverwind commented on GitHub (May 10, 2023):

I guess introducing a full featured webp/png converter would bloat Gitea not just a little

If I recall correctly, gitea already converts all uploaded avatars to PNG, so we do already feature the PNG encoder. Problem is just that the encoding is not doing any compression I think, resulting in unnecessarly huge avatar image sizes.

@silverwind commented on GitHub (May 10, 2023): > I guess introducing a full featured webp/png converter would bloat Gitea not just a little If I recall correctly, gitea already converts all uploaded avatars to PNG, so we do already feature the PNG encoder. Problem is just that the encoding is not doing any compression I think, resulting in unnecessarly huge avatar image sizes.

GiteaMirror commented

@wxiaoguang commented on GitHub (May 10, 2023):

IMO CGO is somewhat better than CCGO at the moment, CCGO is not that popular and users will be locked in it (there is a stale PR: "Pure Go SQLIite", IIRC it also uses CCGO ....)

Of course CGO is not ideal either, it affects generated executable.

A new brief idea: introduce sidecar/external-plugin mechanism: provide a "GiteaImageConvert" server, if users need it, they could deploy it with Gitea together, then Gitea will use it to convert images. If such mechanism can be made general and stable enough, the CustomAvatarServer/PagesServer and more features could be integrated with Gitea while keeping Gitea itself as simple as possible.

@wxiaoguang commented on GitHub (May 10, 2023): IMO CGO is somewhat better than CCGO at the moment, CCGO is not that popular and users will be locked in it (there is a stale PR: "Pure Go SQLIite", IIRC it also uses CCGO ....) Of course CGO is not ideal either, it affects generated executable. A new brief idea: introduce sidecar/external-plugin mechanism: provide a "GiteaImageConvert" server, if users need it, they could deploy it with Gitea together, then Gitea will use it to convert images. If such mechanism can be made general and stable enough, the CustomAvatarServer/PagesServer and more features could be integrated with Gitea while keeping Gitea itself as simple as possible.

GiteaMirror commented

@silverwind commented on GitHub (May 10, 2023):

A new brief idea: introduce sidecar/external-plugin mechanism: provide a "GiteaImageConvert" server, if users need it, they could deploy it with Gitea together, then Gitea will use it to convert images. If such mechanism can be made general and stable enough, the CustomAvatarServer/PagesServer and more features could be integrated with Gitea while keeping Gitea itself as simple as possible.

I'd certainly not see this necessary for the avatar encoder. png encode is in the stdlib so will be forever stable.

@silverwind commented on GitHub (May 10, 2023): > A new brief idea: introduce sidecar/external-plugin mechanism: provide a "GiteaImageConvert" server, if users need it, they could deploy it with Gitea together, then Gitea will use it to convert images. If such mechanism can be made general and stable enough, the CustomAvatarServer/PagesServer and more features could be integrated with Gitea while keeping Gitea itself as simple as possible. I'd certainly not see this necessary for the avatar encoder. [png encode](https://pkg.go.dev/image/png#Encode) is in the stdlib so will be forever stable.

GiteaMirror commented

@wxiaoguang commented on GitHub (May 10, 2023):

The problem is webp ......

@wxiaoguang commented on GitHub (May 10, 2023): The problem is `webp` ......

GiteaMirror commented

@silverwind commented on GitHub (May 10, 2023):

Yes, webp is another topic, but i don't think it's one to invest too much time into currently as the size benefits over PNG aren't that great if both are compressed well. Sooner or later, a proper pure golang webp encoder will emerge and then we will use it.

@silverwind commented on GitHub (May 10, 2023): Yes, webp is another topic, but i don't think it's one to invest too much time into currently as the size benefits over PNG aren't that great if both are compressed well. Sooner or later, a proper pure golang webp encoder will emerge and then we will use it.

GiteaMirror commented

@wxiaoguang commented on GitHub (May 10, 2023):

Problem is just that the encoding is not doing any compression I think, resulting in unnecessarly huge avatar image sizes.

After reading the code, I think png.Encode already does default compression.

png.Encode -> writeIDATs -> e.writeImage(e.bw, e.m, e.cb, levelToZlib(e.enc.CompressionLevel))

The CompressionLevel defaults to 0, aka DefaultCompression -> zlib.DefaultCompression

But, the affect is not good?

@wxiaoguang commented on GitHub (May 10, 2023): > Problem is just that the encoding is not doing any compression I think, resulting in unnecessarly huge avatar image sizes. After reading the code, I think `png.Encode` already does `default compression`. `png.Encode -> writeIDATs -> e.writeImage(e.bw, e.m, e.cb, levelToZlib(e.enc.CompressionLevel))` The `CompressionLevel` defaults to 0, aka DefaultCompression -> zlib.DefaultCompression But, the affect is not good?

GiteaMirror commented

@silverwind commented on GitHub (May 10, 2023):

I didn't test this, but if https://github.com/go-gitea/gitea/issues/8972#issuecomment-1542513735 is to be believed, something may be wrong, either the upsizing (that we should remove and only downsize above 1 megapixel) or the compression would be my guess.

@silverwind commented on GitHub (May 10, 2023): I didn't test this, but if https://github.com/go-gitea/gitea/issues/8972#issuecomment-1542513735 is to be believed, something may be wrong, either the upsizing (that we should remove and only downsize above 1 megapixel) or the compression would be my guess.

GiteaMirror commented

@sosasees commented on GitHub (May 10, 2023):

we should downsize to 1024px² instead of 1000px²
so that the downsized images could be rendered slightly faster.

citation: Make Better Textures, The 'Power Of Two' Rule & Proper Image Dimensions (this is for games but i think it applies to computer images everywhere)

@sosasees commented on GitHub (May 10, 2023): we should downsize to 1024px² instead of 1000px² so that the downsized images could be rendered slightly faster. citation: [Make Better Textures, The 'Power Of Two' Rule & Proper Image Dimensions](https://www.katsbits.com/tutorials/textures/make-better-textures-correct-size-and-power-of-two.php) (this is for games but i think it applies to computer images everywhere)

GiteaMirror commented

@silverwind commented on GitHub (May 10, 2023):

we should downsize to 1024px² instead of 1000px² so that the downsized images could be rendered slightly faster.

Good idea, that makes the downsize threshold 1048576 pixels then.

@silverwind commented on GitHub (May 10, 2023): > we should downsize to 1024px² instead of 1000px² so that the downsized images could be rendered slightly faster. Good idea, that makes the downsize threshold 1048576 pixels then.

GiteaMirror commented

23ae939ef3/modules/avatar/avatar.go (L47-L86)

@zeripath commented on GitHub (May 10, 2023):

OK now I have a PR that will make avatars webp we can look at the resize/crop code.

Its helpful first to understand what we already have:

func Prepare(data []byte) (*image.Image, error) { ... }

We reject if the image is greater than MaxWidth, MaxHeight:

23ae939ef3/modules/avatar/avatar.go (L52-L57)

Default values are:

23ae939ef3/modules/setting/picture.go (L17-L18)

This rejection is important because resize and crop will create RGBA images - so those could be huge byte slices.

If we are not a square image we crop to a square at the centre of the image:

23ae939ef3/modules/avatar/avatar.go (L64-L82)

We resize the avatar to the constant AvatarSize:

23ae939ef3/modules/avatar/avatar.go (L84)

23ae939ef3/modules/avatar/avatar.go (L26)

So we are currently downsizing/upsizing everything to 290 x 290 pixels.

Proposal

Drop the crop code portion
Only resize if imgCfg.Width > 290 || imgCfg.Height > 290
Let maxDim = max(imgCfg.Width, imgCfg.Height)
Resize to imgCfg.Width/maxDim*290, imgCfg.Height / maxDim * 290

@zeripath commented on GitHub (May 10, 2023): OK now I have a PR that will make avatars webp we can look at the resize/crop code. Its helpful first to understand what we already have: <details><summary> func Prepare(data []byte) (*image.Image, error) { ... } </summary> https://github.com/go-gitea/gitea/blob/23ae939ef3ef03848038372de21490725855b5f9/modules/avatar/avatar.go#L47-L86 </details> 1. We reject if the image is greater than MaxWidth, MaxHeight: https://github.com/go-gitea/gitea/blob/23ae939ef3ef03848038372de21490725855b5f9/modules/avatar/avatar.go#L52-L57 Default values are: https://github.com/go-gitea/gitea/blob/23ae939ef3ef03848038372de21490725855b5f9/modules/setting/picture.go#L17-L18 This rejection is important because resize and crop will create RGBA images - so those could be huge byte slices. 2. If we are not a square image we crop to a square at the centre of the image: https://github.com/go-gitea/gitea/blob/23ae939ef3ef03848038372de21490725855b5f9/modules/avatar/avatar.go#L64-L82 3. We resize the avatar to the constant AvatarSize: https://github.com/go-gitea/gitea/blob/23ae939ef3ef03848038372de21490725855b5f9/modules/avatar/avatar.go#L84 https://github.com/go-gitea/gitea/blob/23ae939ef3ef03848038372de21490725855b5f9/modules/avatar/avatar.go#L26 So we are currently downsizing/upsizing everything to 290 x 290 pixels. ---- ## Proposal 1. Drop the `crop` code portion 2. Only resize if `imgCfg.Width > 290 || imgCfg.Height > 290` 3. Let `maxDim = max(imgCfg.Width, imgCfg.Height)` 4. Resize to `imgCfg.Width/maxDim*290, imgCfg.Height / maxDim * 290`

GiteaMirror commented

@silverwind commented on GitHub (May 10, 2023):

Only resize if imgCfg.Width > 290 || imgCfg.Height > 290

Resize to imgCfg.Width/maxDim*290, imgCfg.Height / maxDim * 290

I see 290 was chosen because it is the size of the biggest rendered avatar on the user page. But we should actually take into account Avatar.RenderedSizeFactor for this resize, so that would with the default value of 3 make the size 870 above which to resize and to which resize to.

Other points sound good.

@silverwind commented on GitHub (May 10, 2023): > 2. Only resize if imgCfg.Width > 290 || imgCfg.Height > 290 > 4. Resize to imgCfg.Width/maxDim*290, imgCfg.Height / maxDim * 290 I see 290 was chosen because it is the size of the biggest rendered avatar on the user page. But we should actually take into account `Avatar.RenderedSizeFactor` for this resize, so that would with the default value of 3 make the size 870 above which to resize and to which resize to. Other points sound good.

GiteaMirror commented