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author | Joe Mooring <[email protected]> | 2023-10-27 20:19:39 -0700 |
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committer | Bjørn Erik Pedersen <[email protected]> | 2023-10-29 10:16:37 +0100 |
commit | 3ed28e4bfe2d333fdf1ca2434b57cfc10c3d9791 (patch) | |
tree | 165df55f1f5090b98423be2d8c1d7e78ad7bee41 /resources/images | |
parent | db14238ba323279b28e7ad4cfff5aa10909ccd18 (diff) | |
download | hugo-3ed28e4bfe2d333fdf1ca2434b57cfc10c3d9791.tar.gz hugo-3ed28e4bfe2d333fdf1ca2434b57cfc10c3d9791.zip |
resources/images: Create padding image filter
Closes #11599
Diffstat (limited to 'resources/images')
-rw-r--r-- | resources/images/color.go | 8 | ||||
-rw-r--r-- | resources/images/filters.go | 64 | ||||
-rw-r--r-- | resources/images/padding.go | 50 |
3 files changed, 119 insertions, 3 deletions
diff --git a/resources/images/color.go b/resources/images/color.go index 0eedecb89..fe891fe88 100644 --- a/resources/images/color.go +++ b/resources/images/color.go @@ -56,13 +56,13 @@ func ColorToHexString(c color.Color) string { func hexStringToColor(s string) (color.Color, error) { s = strings.TrimPrefix(s, "#") - if len(s) != 3 && len(s) != 6 { + if len(s) != 3 && len(s) != 4 && len(s) != 6 && len(s) != 8 { return nil, fmt.Errorf("invalid color code: %q", s) } s = strings.ToLower(s) - if len(s) == 3 { + if len(s) == 3 || len(s) == 4 { var v string for _, r := range s { v += string(r) + string(r) @@ -80,7 +80,9 @@ func hexStringToColor(s string) (color.Color, error) { } // Set Alfa to white. - s += "ff" + if len(s) == 6 { + s += "ff" + } b, err := hex.DecodeString(s) if err != nil { diff --git a/resources/images/filters.go b/resources/images/filters.go index dca8ff0e8..2a1f41a03 100644 --- a/resources/images/filters.go +++ b/resources/images/filters.go @@ -16,6 +16,7 @@ package images import ( "fmt" + "image/color" "github.com/gohugoio/hugo/common/hugio" "github.com/gohugoio/hugo/common/maps" @@ -30,6 +31,7 @@ const filterAPIVersion = 0 type Filters struct{} +// Process creates a filter that processes an image using the given specification. func (*Filters) Process(spec any) gift.Filter { return filter{ Options: newFilterOpts(spec), @@ -110,6 +112,68 @@ func (*Filters) Text(text string, options ...any) gift.Filter { } } +// Padding creates a filter that resizes the image canvas without resizing the +// image. The last argument is the canvas color, expressed as an RGB or RGBA +// hexadecimal color. The default value is `ffffffff` (opaque white). The +// preceding arguments are the padding values, in pixels, using the CSS +// shorthand property syntax. Negative padding values will crop the image. The +// signature is images.Padding V1 [V2] [V3] [V4] [COLOR]. +func (*Filters) Padding(args ...any) gift.Filter { + if len(args) < 1 || len(args) > 5 { + panic("the padding filter requires between 1 and 5 arguments") + } + + var top, right, bottom, left int + var ccolor color.Color = color.White // canvas color + var err error + + _args := args // preserve original args for most stable hash + + if vcs, ok := (args[len(args)-1]).(string); ok { + ccolor, err = hexStringToColor(vcs) + if err != nil { + panic("invalid canvas color: specify RGB or RGBA using hex notation") + } + args = args[:len(args)-1] + if len(args) == 0 { + panic("not enough arguments: provide one or more padding values using the CSS shorthand property syntax") + } + } + + var vals []int + for _, v := range args { + vi := cast.ToInt(v) + if vi > 5000 { + panic("padding values must not exceed 5000 pixels") + } + vals = append(vals, vi) + } + + switch len(args) { + case 1: + top, right, bottom, left = vals[0], vals[0], vals[0], vals[0] + case 2: + top, right, bottom, left = vals[0], vals[1], vals[0], vals[1] + case 3: + top, right, bottom, left = vals[0], vals[1], vals[2], vals[1] + case 4: + top, right, bottom, left = vals[0], vals[1], vals[2], vals[3] + default: + panic(fmt.Sprintf("too many padding values: received %d, expected maximum of 4", len(args))) + } + + return filter{ + Options: newFilterOpts(_args...), + Filter: paddingFilter{ + top: top, + right: right, + bottom: bottom, + left: left, + ccolor: ccolor, + }, + } +} + // Brightness creates a filter that changes the brightness of an image. // The percentage parameter must be in range (-100, 100). func (*Filters) Brightness(percentage any) gift.Filter { diff --git a/resources/images/padding.go b/resources/images/padding.go new file mode 100644 index 000000000..153d0bd82 --- /dev/null +++ b/resources/images/padding.go @@ -0,0 +1,50 @@ +// 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 = (*paddingFilter)(nil) + +type paddingFilter struct { + top, right, bottom, left int + ccolor color.Color // canvas color +} + +func (f paddingFilter) Draw(dst draw.Image, src image.Image, options *gift.Options) { + w := src.Bounds().Dx() + f.left + f.right + h := src.Bounds().Dy() + f.top + f.bottom + + if w < 1 { + panic("final image width will be less than 1 pixel: check padding values") + } + if h < 1 { + panic("final image height will be less than 1 pixel: check padding values") + } + + i := image.NewRGBA(image.Rect(0, 0, w, h)) + draw.Draw(i, i.Bounds(), image.NewUniform(f.ccolor), image.Point{}, draw.Src) + gift.New().Draw(dst, i) + gift.New().DrawAt(dst, src, image.Pt(f.left, f.top), gift.OverOperator) +} + +func (f paddingFilter) Bounds(srcBounds image.Rectangle) image.Rectangle { + return image.Rect(0, 0, srcBounds.Dx()+f.left+f.right, srcBounds.Dy()+f.top+f.bottom) +} |