mirror of
https://github.com/gohugoio/hugo.git
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104 lines
2.9 KiB
Go
104 lines
2.9 KiB
Go
// Copyright 2019 The Hugo Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package images
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import (
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"image"
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"math"
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"github.com/disintegration/gift"
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"github.com/muesli/smartcrop"
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)
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const (
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// Do not change.
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smartCropIdentifier = "smart"
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// This is just a increment, starting on 1. If Smart Crop improves its cropping, we
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// need a way to trigger a re-generation of the crops in the wild, so increment this.
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smartCropVersionNumber = 1
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)
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func (p *ImageProcessor) newSmartCropAnalyzer(filter gift.Resampling) smartcrop.Analyzer {
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return smartcrop.NewAnalyzer(imagingResizer{p: p, filter: filter})
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}
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// Needed by smartcrop
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type imagingResizer struct {
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p *ImageProcessor
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filter gift.Resampling
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}
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func (r imagingResizer) Resize(img image.Image, width, height uint) image.Image {
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// See https://github.com/gohugoio/hugo/issues/7955#issuecomment-861710681
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scaleX, scaleY := calcFactorsNfnt(width, height, float64(img.Bounds().Dx()), float64(img.Bounds().Dy()))
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if width == 0 {
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width = uint(math.Ceil(float64(img.Bounds().Dx()) / scaleX))
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}
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if height == 0 {
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height = uint(math.Ceil(float64(img.Bounds().Dy()) / scaleY))
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}
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result, _ := r.p.Filter(img, gift.Resize(int(width), int(height), r.filter))
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return result
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}
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func (p *ImageProcessor) smartCrop(img image.Image, width, height int, filter gift.Resampling) (image.Rectangle, error) {
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if width <= 0 || height <= 0 {
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return image.Rectangle{}, nil
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}
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srcBounds := img.Bounds()
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srcW := srcBounds.Dx()
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srcH := srcBounds.Dy()
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if srcW <= 0 || srcH <= 0 {
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return image.Rectangle{}, nil
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}
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if srcW == width && srcH == height {
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return srcBounds, nil
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}
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smart := p.newSmartCropAnalyzer(filter)
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rect, err := smart.FindBestCrop(img, width, height)
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if err != nil {
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return image.Rectangle{}, err
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}
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return img.Bounds().Intersect(rect), nil
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}
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// Calculates scaling factors using old and new image dimensions.
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// Code borrowed from https://github.com/nfnt/resize/blob/83c6a9932646f83e3267f353373d47347b6036b2/resize.go#L593
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func calcFactorsNfnt(width, height uint, oldWidth, oldHeight float64) (scaleX, scaleY float64) {
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if width == 0 {
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if height == 0 {
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scaleX = 1.0
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scaleY = 1.0
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} else {
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scaleY = oldHeight / float64(height)
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scaleX = scaleY
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}
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} else {
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scaleX = oldWidth / float64(width)
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if height == 0 {
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scaleY = scaleX
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} else {
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scaleY = oldHeight / float64(height)
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}
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}
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return
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}
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