hugo/resources/images/overlay.go
Bjørn Erik Pedersen 3ba147e702 images: Add images.Overlay filter
This allows for constructs ala:

```
{{ $overlay := $img.Filter (images.Overlay $logo 50 50 )}}
```
Or:

```
{{ $logoFilter := (images.Overlay $logo 50 50 ) }}
{{ $overlay := $img | images.Filter $logoFilter }}
```

Which will overlay the logo in the top left corner (x=50, y=50) of `$img`.

Fixes #8057
Fixes #4595
Updates #6731
2020-12-17 09:14:18 +01:00

43 lines
1.2 KiB
Go

// Copyright 2020 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package images
import (
"fmt"
"image"
"image/draw"
"github.com/disintegration/gift"
)
var _ gift.Filter = (*overlayFilter)(nil)
type overlayFilter struct {
src ImageSource
x, y int
}
func (f overlayFilter) Draw(dst draw.Image, src image.Image, options *gift.Options) {
overlaySrc, err := f.src.DecodeImage()
if err != nil {
panic(fmt.Sprintf("failed to decode image: %s", err))
}
gift.New().Draw(dst, src)
gift.New().DrawAt(dst, overlaySrc, image.Pt(f.x, f.y), gift.OverOperator)
}
func (f overlayFilter) Bounds(srcBounds image.Rectangle) image.Rectangle {
return image.Rect(0, 0, srcBounds.Dx(), srcBounds.Dy())
}