mirror of
https://github.com/gohugoio/hugo.git
synced 2024-11-21 20:46:30 -05:00
40 lines
1.2 KiB
Go
40 lines
1.2 KiB
Go
|
// Copyright 2023 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 (
|
||
|
|
"image"
|
||
|
|
"image/color"
|
||
|
|
"image/draw"
|
||
|
|
|
||
|
|
"github.com/disintegration/gift"
|
||
|
|
)
|
||
|
|
|
||
|
|
var _ gift.Filter = (*opacityFilter)(nil)
|
||
|
|
|
||
|
|
type opacityFilter struct {
|
||
|
|
opacity float32
|
||
|
|
}
|
||
|
|
|
||
|
|
func (f opacityFilter) Draw(dst draw.Image, src image.Image, options *gift.Options) {
|
||
|
|
// 0 is fully transparent and 255 is opaque.
|
||
|
|
alpha := uint8(f.opacity * 255)
|
||
|
|
mask := image.NewUniform(color.Alpha{alpha})
|
||
|
|
draw.DrawMask(dst, dst.Bounds(), src, image.Point{}, mask, image.Point{}, draw.Over)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (f opacityFilter) Bounds(srcBounds image.Rectangle) image.Rectangle {
|
||
|
|
return image.Rect(0, 0, srcBounds.Dx(), srcBounds.Dy())
|
||
|
|
}
|