Improve handling of non-square avatars (#7025)

* Crop avatar before resizing (#1268)

Signed-off-by: Rob Watson <rfwatson@users.noreply.github.com>

* Fix spelling error

Signed-off-by: Rob Watson <rfwatson@users.noreply.github.com>

4 files changed, 99 insertions, 0 deletions

diff --git a/modules/avatar/avatar.go b/modules/avatar/avatar.go
index f426978b32..cf3da6df5e 100644
--- a/modules/avatar/avatar.go
+++ b/modules/avatar/avatar.go
@@ -5,13 +5,20 @@
 package avatar
 
 import (
+	"bytes"
 	"fmt"
 	"image"
 	"image/color/palette"
+	// Enable PNG support:
+	_ "image/png"
 	"math/rand"
 	"time"
 
+	"code.gitea.io/gitea/modules/setting"
+
 	"github.com/issue9/identicon"
+	"github.com/nfnt/resize"
+	"github.com/oliamb/cutter"
 )
 
 // AvatarSize returns avatar's size
@@ -42,3 +49,46 @@ func RandomImageSize(size int, data []byte) (image.Image, error) {
 func RandomImage(data []byte) (image.Image, error) {
 	return RandomImageSize(AvatarSize, data)
 }
+
+// Prepare accepts a byte slice as input, validates it contains an image of an
+// acceptable format, and crops and resizes it appropriately.
+func Prepare(data []byte) (*image.Image, error) {
+	imgCfg, _, err := image.DecodeConfig(bytes.NewReader(data))
+	if err != nil {
+		return nil, fmt.Errorf("DecodeConfig: %v", err)
+	}
+	if imgCfg.Width > setting.AvatarMaxWidth {
+		return nil, fmt.Errorf("Image width is too large: %d > %d", imgCfg.Width, setting.AvatarMaxWidth)
+	}
+	if imgCfg.Height > setting.AvatarMaxHeight {
+		return nil, fmt.Errorf("Image height is too large: %d > %d", imgCfg.Height, setting.AvatarMaxHeight)
+	}
+
+	img, _, err := image.Decode(bytes.NewReader(data))
+	if err != nil {
+		return nil, fmt.Errorf("Decode: %v", err)
+	}
+
+	if imgCfg.Width != imgCfg.Height {
+		var newSize, ax, ay int
+		if imgCfg.Width > imgCfg.Height {
+			newSize = imgCfg.Height
+			ax = (imgCfg.Width - imgCfg.Height) / 2
+		} else {
+			newSize = imgCfg.Width
+			ay = (imgCfg.Height - imgCfg.Width) / 2
+		}
+
+		img, err = cutter.Crop(img, cutter.Config{
+			Width:  newSize,
+			Height: newSize,
+			Anchor: image.Point{ax, ay},
+		})
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	img = resize.Resize(AvatarSize, AvatarSize, img, resize.NearestNeighbor)
+	return &img, nil
+}
diff --git a/modules/avatar/avatar_test.go b/modules/avatar/avatar_test.go
index 9eff5bc2be..662d50fadd 100644
--- a/modules/avatar/avatar_test.go
+++ b/modules/avatar/avatar_test.go
@@ -5,8 +5,11 @@
 package avatar
 
 import (
+	"io/ioutil"
 	"testing"
 
+	"code.gitea.io/gitea/modules/setting"
+
 	"github.com/stretchr/testify/assert"
 )
 
@@ -17,3 +20,49 @@ func Test_RandomImage(t *testing.T) {
 	_, err = RandomImageSize(0, []byte("gogs@local"))
 	assert.Error(t, err)
 }
+
+func Test_PrepareWithPNG(t *testing.T) {
+	setting.AvatarMaxWidth = 4096
+	setting.AvatarMaxHeight = 4096
+
+	data, err := ioutil.ReadFile("testdata/avatar.png")
+	assert.NoError(t, err)
+
+	imgPtr, err := Prepare(data)
+	assert.NoError(t, err)
+
+	assert.Equal(t, 290, (*imgPtr).Bounds().Max.X)
+	assert.Equal(t, 290, (*imgPtr).Bounds().Max.Y)
+}
+
+func Test_PrepareWithJPEG(t *testing.T) {
+	setting.AvatarMaxWidth = 4096
+	setting.AvatarMaxHeight = 4096
+
+	data, err := ioutil.ReadFile("testdata/avatar.jpeg")
+	assert.NoError(t, err)
+
+	imgPtr, err := Prepare(data)
+	assert.NoError(t, err)
+
+	assert.Equal(t, 290, (*imgPtr).Bounds().Max.X)
+	assert.Equal(t, 290, (*imgPtr).Bounds().Max.Y)
+}
+
+func Test_PrepareWithInvalidImage(t *testing.T) {
+	setting.AvatarMaxWidth = 5
+	setting.AvatarMaxHeight = 5
+
+	_, err := Prepare([]byte{})
+	assert.EqualError(t, err, "DecodeConfig: image: unknown format")
+}
+func Test_PrepareWithInvalidImageSize(t *testing.T) {
+	setting.AvatarMaxWidth = 5
+	setting.AvatarMaxHeight = 5
+
+	data, err := ioutil.ReadFile("testdata/avatar.png")
+	assert.NoError(t, err)
+
+	_, err = Prepare(data)
+	assert.EqualError(t, err, "Image width is too large: 10 > 5")
+}
diff --git a/modules/avatar/testdata/avatar.jpeg b/modules/avatar/testdata/avatar.jpeg
new file mode 100644
index 0000000000..892b7baf78
--- /dev/null
+++ b/modules/avatar/testdata/avatar.jpeg
diff --git a/modules/avatar/testdata/avatar.png b/modules/avatar/testdata/avatar.png
new file mode 100644
index 0000000000..c0f7922961
--- /dev/null
+++ b/modules/avatar/testdata/avatar.png