ref: f9978ed16476ca6d233a89669c62c798cdf9db9d
dir: /resources/images/config.go/
// Copyright 2019 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 (
"errors"
"fmt"
"strconv"
"strings"
"github.com/disintegration/imaging"
"github.com/mitchellh/mapstructure"
)
const (
defaultJPEGQuality = 75
defaultResampleFilter = "box"
)
var (
imageFormats = map[string]imaging.Format{
".jpg": imaging.JPEG,
".jpeg": imaging.JPEG,
".png": imaging.PNG,
".tif": imaging.TIFF,
".tiff": imaging.TIFF,
".bmp": imaging.BMP,
".gif": imaging.GIF,
}
// Add or increment if changes to an image format's processing requires
// re-generation.
imageFormatsVersions = map[imaging.Format]int{
imaging.PNG: 2, // Floyd Steinberg dithering
}
// Increment to mark all processed images as stale. Only use when absolutely needed.
// See the finer grained smartCropVersionNumber and imageFormatsVersions.
mainImageVersionNumber = 0
// Increment to mark all traced SVGs as stale.
traceVersionNumber = 0
)
var anchorPositions = map[string]imaging.Anchor{
strings.ToLower("Center"): imaging.Center,
strings.ToLower("TopLeft"): imaging.TopLeft,
strings.ToLower("Top"): imaging.Top,
strings.ToLower("TopRight"): imaging.TopRight,
strings.ToLower("Left"): imaging.Left,
strings.ToLower("Right"): imaging.Right,
strings.ToLower("BottomLeft"): imaging.BottomLeft,
strings.ToLower("Bottom"): imaging.Bottom,
strings.ToLower("BottomRight"): imaging.BottomRight,
}
var imageFilters = map[string]imaging.ResampleFilter{
strings.ToLower("NearestNeighbor"): imaging.NearestNeighbor,
strings.ToLower("Box"): imaging.Box,
strings.ToLower("Linear"): imaging.Linear,
strings.ToLower("Hermite"): imaging.Hermite,
strings.ToLower("MitchellNetravali"): imaging.MitchellNetravali,
strings.ToLower("CatmullRom"): imaging.CatmullRom,
strings.ToLower("BSpline"): imaging.BSpline,
strings.ToLower("Gaussian"): imaging.Gaussian,
strings.ToLower("Lanczos"): imaging.Lanczos,
strings.ToLower("Hann"): imaging.Hann,
strings.ToLower("Hamming"): imaging.Hamming,
strings.ToLower("Blackman"): imaging.Blackman,
strings.ToLower("Bartlett"): imaging.Bartlett,
strings.ToLower("Welch"): imaging.Welch,
strings.ToLower("Cosine"): imaging.Cosine,
}
func ImageFormatFromExt(ext string) (imaging.Format, bool) {
f, found := imageFormats[ext]
return f, found
}
func DecodeConfig(m map[string]interface{}) (Imaging, error) {
var i Imaging
if err := mapstructure.WeakDecode(m, &i); err != nil {
return i, err
}
if i.Quality == 0 {
i.Quality = defaultJPEGQuality
} else if i.Quality < 0 || i.Quality > 100 {
return i, errors.New("JPEG quality must be a number between 1 and 100")
}
if i.Anchor == "" || strings.EqualFold(i.Anchor, SmartCropIdentifier) {
i.Anchor = SmartCropIdentifier
} else {
i.Anchor = strings.ToLower(i.Anchor)
if _, found := anchorPositions[i.Anchor]; !found {
return i, errors.New("invalid anchor value in imaging config")
}
}
if i.ResampleFilter == "" {
i.ResampleFilter = defaultResampleFilter
} else {
filter := strings.ToLower(i.ResampleFilter)
_, found := imageFilters[filter]
if !found {
return i, fmt.Errorf("%q is not a valid resample filter", filter)
}
i.ResampleFilter = filter
}
return i, nil
}
func DecodeImageConfig(action, config string, defaults Imaging) (ImageConfig, error) {
var (
c ImageConfig
err error
)
c.Action = action
if config == "" {
return c, errors.New("image config cannot be empty")
}
parts := strings.Fields(config)
for _, part := range parts {
part = strings.ToLower(part)
if part == SmartCropIdentifier {
c.AnchorStr = SmartCropIdentifier
} else if pos, ok := anchorPositions[part]; ok {
c.Anchor = pos
c.AnchorStr = part
} else if filter, ok := imageFilters[part]; ok {
c.Filter = filter
c.FilterStr = part
} else if part[0] == 'q' {
c.Quality, err = strconv.Atoi(part[1:])
if err != nil {
return c, err
}
if c.Quality < 1 || c.Quality > 100 {
return c, errors.New("quality ranges from 1 to 100 inclusive")
}
} else if part[0] == 'r' {
c.Rotate, err = strconv.Atoi(part[1:])
if err != nil {
return c, err
}
} else if strings.Contains(part, "x") {
widthHeight := strings.Split(part, "x")
if len(widthHeight) <= 2 {
first := widthHeight[0]
if first != "" {
c.Width, err = strconv.Atoi(first)
if err != nil {
return c, err
}
}
if len(widthHeight) == 2 {
second := widthHeight[1]
if second != "" {
c.Height, err = strconv.Atoi(second)
if err != nil {
return c, err
}
}
}
} else {
return c, errors.New("invalid image dimensions")
}
}
}
if c.Width == 0 && c.Height == 0 {
return c, errors.New("must provide Width or Height")
}
if c.FilterStr == "" {
c.FilterStr = defaults.ResampleFilter
c.Filter = imageFilters[c.FilterStr]
}
if c.AnchorStr == "" {
c.AnchorStr = defaults.Anchor
if !strings.EqualFold(c.AnchorStr, SmartCropIdentifier) {
c.Anchor = anchorPositions[c.AnchorStr]
}
}
return c, nil
}
// ImageConfig holds configuration to create a new image from an existing one, resize etc.
type ImageConfig struct {
Action string
// Quality ranges from 1 to 100 inclusive, higher is better.
// This is only relevant for JPEG images.
// Default is 75.
Quality int
// Rotate rotates an image by the given angle counter-clockwise.
// The rotation will be performed first.
Rotate int
Width int
Height int
Filter imaging.ResampleFilter
FilterStr string
Anchor imaging.Anchor
AnchorStr string
}
func (i ImageConfig) Key(format imaging.Format) string {
k := strconv.Itoa(i.Width) + "x" + strconv.Itoa(i.Height)
if i.Action != "" {
k += "_" + i.Action
}
if i.Quality > 0 {
k += "_q" + strconv.Itoa(i.Quality)
}
if i.Rotate != 0 {
k += "_r" + strconv.Itoa(i.Rotate)
}
anchor := i.AnchorStr
if anchor == SmartCropIdentifier {
anchor = anchor + strconv.Itoa(smartCropVersionNumber)
}
k += "_" + i.FilterStr
if strings.EqualFold(i.Action, "fill") {
k += "_" + anchor
}
if v, ok := imageFormatsVersions[format]; ok {
k += "_" + strconv.Itoa(v)
}
if mainImageVersionNumber > 0 {
k += "_" + strconv.Itoa(mainImageVersionNumber)
}
return k
}
// Imaging contains default image processing configuration. This will be fetched
// from site (or language) config.
type Imaging struct {
// Default image quality setting (1-100). Only used for JPEG images.
Quality int
// Resample filter used. See https://github.com/disintegration/imaging
ResampleFilter string
// The anchor used in Fill. Default is "smart", i.e. Smart Crop.
Anchor string
}