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317 lines
9.7 KiB
Go
317 lines
9.7 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 provides template functions for manipulating images.
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package images
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import (
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"fmt"
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"image/color"
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"github.com/gohugoio/hugo/common/hugio"
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"github.com/gohugoio/hugo/common/maps"
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"github.com/gohugoio/hugo/resources/resource"
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"github.com/disintegration/gift"
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"github.com/spf13/cast"
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)
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// Increment for re-generation of images using these filters.
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const filterAPIVersion = 0
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type Filters struct{}
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// Process creates a filter that processes an image using the given specification.
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func (*Filters) Process(spec any) gift.Filter {
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return filter{
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Options: newFilterOpts(spec),
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Filter: processFilter{
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spec: cast.ToString(spec),
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},
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}
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}
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// Overlay creates a filter that overlays src at position x y.
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func (*Filters) Overlay(src ImageSource, x, y any) gift.Filter {
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return filter{
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Options: newFilterOpts(src.Key(), x, y),
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Filter: overlayFilter{src: src, x: cast.ToInt(x), y: cast.ToInt(y)},
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}
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}
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// Opacity creates a filter that changes the opacity of an image.
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// The opacity parameter must be in range (0, 1).
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func (*Filters) Opacity(opacity any) gift.Filter {
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return filter{
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Options: newFilterOpts(opacity),
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Filter: opacityFilter{opacity: cast.ToFloat32(opacity)},
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}
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}
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// Text creates a filter that draws text with the given options.
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func (*Filters) Text(text string, options ...any) gift.Filter {
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tf := textFilter{
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text: text,
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color: "#ffffff",
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size: 20,
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x: 10,
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y: 10,
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linespacing: 2,
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}
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var opt maps.Params
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if len(options) > 0 {
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opt = maps.MustToParamsAndPrepare(options[0])
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for option, v := range opt {
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switch option {
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case "color":
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tf.color = cast.ToString(v)
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case "size":
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tf.size = cast.ToFloat64(v)
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case "x":
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tf.x = cast.ToInt(v)
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case "y":
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tf.y = cast.ToInt(v)
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case "linespacing":
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tf.linespacing = cast.ToInt(v)
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case "font":
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if err, ok := v.(error); ok {
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panic(fmt.Sprintf("invalid font source: %s", err))
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}
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fontSource, ok1 := v.(hugio.ReadSeekCloserProvider)
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identifier, ok2 := v.(resource.Identifier)
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if !(ok1 && ok2) {
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panic(fmt.Sprintf("invalid text font source: %T", v))
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}
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tf.fontSource = fontSource
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// The input value isn't hashable and will not make a stable key.
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// Replace it with a string in the map used as basis for the
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// hash string.
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opt["font"] = identifier.Key()
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}
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}
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}
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return filter{
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Options: newFilterOpts(text, opt),
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Filter: tf,
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}
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}
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// Padding creates a filter that resizes the image canvas without resizing the
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// image. The last argument is the canvas color, expressed as an RGB or RGBA
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// hexadecimal color. The default value is `ffffffff` (opaque white). The
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// preceding arguments are the padding values, in pixels, using the CSS
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// shorthand property syntax. Negative padding values will crop the image. The
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// signature is images.Padding V1 [V2] [V3] [V4] [COLOR].
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func (*Filters) Padding(args ...any) gift.Filter {
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if len(args) < 1 || len(args) > 5 {
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panic("the padding filter requires between 1 and 5 arguments")
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}
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var top, right, bottom, left int
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var ccolor color.Color = color.White // canvas color
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var err error
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_args := args // preserve original args for most stable hash
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if vcs, ok := (args[len(args)-1]).(string); ok {
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ccolor, err = hexStringToColor(vcs)
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if err != nil {
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panic("invalid canvas color: specify RGB or RGBA using hex notation")
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}
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args = args[:len(args)-1]
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if len(args) == 0 {
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panic("not enough arguments: provide one or more padding values using the CSS shorthand property syntax")
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}
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}
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var vals []int
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for _, v := range args {
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vi := cast.ToInt(v)
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if vi > 5000 {
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panic("padding values must not exceed 5000 pixels")
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}
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vals = append(vals, vi)
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}
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switch len(args) {
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case 1:
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top, right, bottom, left = vals[0], vals[0], vals[0], vals[0]
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case 2:
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top, right, bottom, left = vals[0], vals[1], vals[0], vals[1]
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case 3:
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top, right, bottom, left = vals[0], vals[1], vals[2], vals[1]
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case 4:
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top, right, bottom, left = vals[0], vals[1], vals[2], vals[3]
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default:
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panic(fmt.Sprintf("too many padding values: received %d, expected maximum of 4", len(args)))
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}
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return filter{
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Options: newFilterOpts(_args...),
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Filter: paddingFilter{
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top: top,
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right: right,
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bottom: bottom,
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left: left,
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ccolor: ccolor,
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},
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}
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}
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// Brightness creates a filter that changes the brightness of an image.
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// The percentage parameter must be in range (-100, 100).
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func (*Filters) Brightness(percentage any) gift.Filter {
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return filter{
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Options: newFilterOpts(percentage),
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Filter: gift.Brightness(cast.ToFloat32(percentage)),
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}
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}
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// ColorBalance creates a filter that changes the color balance of an image.
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// The percentage parameters for each color channel (red, green, blue) must be in range (-100, 500).
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func (*Filters) ColorBalance(percentageRed, percentageGreen, percentageBlue any) gift.Filter {
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return filter{
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Options: newFilterOpts(percentageRed, percentageGreen, percentageBlue),
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Filter: gift.ColorBalance(cast.ToFloat32(percentageRed), cast.ToFloat32(percentageGreen), cast.ToFloat32(percentageBlue)),
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}
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}
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// Colorize creates a filter that produces a colorized version of an image.
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// The hue parameter is the angle on the color wheel, typically in range (0, 360).
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// The saturation parameter must be in range (0, 100).
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// The percentage parameter specifies the strength of the effect, it must be in range (0, 100).
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func (*Filters) Colorize(hue, saturation, percentage any) gift.Filter {
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return filter{
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Options: newFilterOpts(hue, saturation, percentage),
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Filter: gift.Colorize(cast.ToFloat32(hue), cast.ToFloat32(saturation), cast.ToFloat32(percentage)),
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}
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}
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// Contrast creates a filter that changes the contrast of an image.
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// The percentage parameter must be in range (-100, 100).
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func (*Filters) Contrast(percentage any) gift.Filter {
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return filter{
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Options: newFilterOpts(percentage),
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Filter: gift.Contrast(cast.ToFloat32(percentage)),
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}
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}
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// Gamma creates a filter that performs a gamma correction on an image.
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// The gamma parameter must be positive. Gamma = 1 gives the original image.
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// Gamma less than 1 darkens the image and gamma greater than 1 lightens it.
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func (*Filters) Gamma(gamma any) gift.Filter {
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return filter{
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Options: newFilterOpts(gamma),
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Filter: gift.Gamma(cast.ToFloat32(gamma)),
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}
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}
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// GaussianBlur creates a filter that applies a gaussian blur to an image.
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func (*Filters) GaussianBlur(sigma any) gift.Filter {
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return filter{
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Options: newFilterOpts(sigma),
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Filter: gift.GaussianBlur(cast.ToFloat32(sigma)),
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}
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}
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// Grayscale creates a filter that produces a grayscale version of an image.
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func (*Filters) Grayscale() gift.Filter {
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return filter{
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Filter: gift.Grayscale(),
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}
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}
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// Hue creates a filter that rotates the hue of an image.
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// The hue angle shift is typically in range -180 to 180.
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func (*Filters) Hue(shift any) gift.Filter {
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return filter{
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Options: newFilterOpts(shift),
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Filter: gift.Hue(cast.ToFloat32(shift)),
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}
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}
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// Invert creates a filter that negates the colors of an image.
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func (*Filters) Invert() gift.Filter {
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return filter{
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Filter: gift.Invert(),
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}
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}
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// Pixelate creates a filter that applies a pixelation effect to an image.
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func (*Filters) Pixelate(size any) gift.Filter {
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return filter{
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Options: newFilterOpts(size),
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Filter: gift.Pixelate(cast.ToInt(size)),
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}
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}
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// Saturation creates a filter that changes the saturation of an image.
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func (*Filters) Saturation(percentage any) gift.Filter {
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return filter{
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Options: newFilterOpts(percentage),
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Filter: gift.Saturation(cast.ToFloat32(percentage)),
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}
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}
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// Sepia creates a filter that produces a sepia-toned version of an image.
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func (*Filters) Sepia(percentage any) gift.Filter {
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return filter{
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Options: newFilterOpts(percentage),
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Filter: gift.Sepia(cast.ToFloat32(percentage)),
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}
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}
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// Sigmoid creates a filter that changes the contrast of an image using a sigmoidal function and returns the adjusted image.
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// It's a non-linear contrast change useful for photo adjustments as it preserves highlight and shadow detail.
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func (*Filters) Sigmoid(midpoint, factor any) gift.Filter {
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return filter{
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Options: newFilterOpts(midpoint, factor),
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Filter: gift.Sigmoid(cast.ToFloat32(midpoint), cast.ToFloat32(factor)),
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}
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}
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// UnsharpMask creates a filter that sharpens an image.
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// The sigma parameter is used in a gaussian function and affects the radius of effect.
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// Sigma must be positive. Sharpen radius roughly equals 3 * sigma.
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// The amount parameter controls how much darker and how much lighter the edge borders become. Typically between 0.5 and 1.5.
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// The threshold parameter controls the minimum brightness change that will be sharpened. Typically between 0 and 0.05.
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func (*Filters) UnsharpMask(sigma, amount, threshold any) gift.Filter {
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return filter{
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Options: newFilterOpts(sigma, amount, threshold),
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Filter: gift.UnsharpMask(cast.ToFloat32(sigma), cast.ToFloat32(amount), cast.ToFloat32(threshold)),
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}
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}
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type filter struct {
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Options filterOpts
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gift.Filter
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}
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// For cache-busting.
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type filterOpts struct {
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Version int
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Vals any
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}
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func newFilterOpts(vals ...any) filterOpts {
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return filterOpts{
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Version: filterAPIVersion,
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Vals: vals,
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}
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}
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