tpl: Add image process template functions (draft)

Add image manipulation functions according to draft proposal gohugoio#3158

tpl/tplimpl/template_func_image_process.go

@@ -0,0 +1,348 @@
+// Copyright 2017 The Hugo Authors. All rights reserved.
+//
+// Portions Copyright The Go Authors.
+
+// 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 tplimpl
+
+import (
+	"image"
+	"time"
+	"strconv"
+	"math/rand"
+	_nfntResize "github.com/nfnt/resize"
+	_bildAdjust "github.com/anthonynsimon/bild/adjust"
+	_bildBlend "github.com/anthonynsimon/bild/blend"
+	_bildBlur "github.com/anthonynsimon/bild/blur"
+	_bildTransform "github.com/anthonynsimon/bild/transform"
+	_bildChannel "github.com/anthonynsimon/bild/channel"
+	_bildEffect "github.com/anthonynsimon/bild/effect"
+	_bildImgIo "github.com/anthonynsimon/bild/imgio"
+
+	// help needed: implement _smartCrop struggled installing smartcrop
+	// _smartCrop "github.com/muesli/smartcrop"
+)
+
+// File Handler
+
+func ipOpen(path string) image.Image {
+
+	img, err := _bildImgIo.Open(path)
+	if err != nil {
+		panic(err)
+	}
+
+	return img;
+
+}
+
+func ipSave(img image.Image) string {
+
+	// general:
+	// help needed: method only works when --renderToDisk is enabled
+	// help needed: ipSave should have an optional parameter for filename
+	// help needed: caching strategy?
+
+	// filename:
+	// help needed: should get the md5 checksum of the file content
+	// help needed: should take the file extension from the image instead of fix jpg
+	// help needed: should prefix with a custom filepath from config.toml
+	filename := strconv.Itoa(rand.Intn(50000)) + strconv.FormatInt(time.Now().UTC().UnixNano(), 10) + ".jpg";
+
+	// help needed: should take public from variables not fix set to public
+	publicFilename := "public/" + filename;
+
+	// help needed: should not take _bildImgTo.JPEG as a fix value
+	if err := _bildImgIo.Save(publicFilename, img, _bildImgIo.JPEG); err != nil {
+		panic(err)
+	}
+
+	/*
+	Should return:
+	{
+	  "Permalink" : "https://example.com/[images/]<filename>.jpg",
+	  "RelPermalink" : "/[<defined path in config.toml images/>]<filename>.jpg",
+	  "Width" : 400,
+	  "Height" : 200
+	}
+	 */
+
+	return filename;
+
+}
+
+// Image Transformation
+
+func ipCrop(img image.Image, x0 int, y0 int, width int, height int) image.Image {
+	rect := image.Rect(x0, y0, (x0 + width), (y0 + height))
+	return _bildTransform.Crop(img, rect)
+}
+
+func ipSmartCrop(img image.Image, width int, height int) image.Image {
+
+	return img;
+
+	// Help needed: unfortunately I receive the following error
+	// trying to install the 'smartcrop'-package
+	// exec: "gcc": executable file not found in %PATH%
+
+	//settings := smartcrop.CropSettings{
+	//	FaceDetection:                    true,
+	//	FaceDetectionHaarCascadeFilepath: "./files/aarcascade_frontalface_alt.xml",
+	//}
+	//analyzer := smartcrop.NewAnalyzerWithCropSettings(settings)
+	//topCrop, _ := analyzer.FindBestCrop(img, width, height)
+	//
+	//return ipCrop(img, topCrop.X, topCrop.Y, topCrop.Width, topCrop.Height);
+}
+
+func ipResize(img image.Image, width uint, height uint, interpolation string) image.Image {
+
+	switch interpolation {
+	case "Bilinear" :
+		return _nfntResize.Resize(width, height, img, _nfntResize.Bilinear);
+		break
+	case "NearestNeighbor" :
+		return _nfntResize.Resize(width, height, img, _nfntResize.NearestNeighbor);
+		break
+	case "Bicubic" :
+		return _nfntResize.Resize(width, height, img, _nfntResize.Bicubic);
+		break
+	case "MitchellNetravali" :
+		return _nfntResize.Resize(width, height, img, _nfntResize.MitchellNetravali);
+		break
+	case "Lanczos2" :
+		return _nfntResize.Resize(width, height, img, _nfntResize.Lanczos2);
+		break
+	case "Lanczos3" :
+		return _nfntResize.Resize(width, height, img, _nfntResize.Lanczos3);
+		break
+	default :
+		return _nfntResize.Resize(width, height, img, _nfntResize.NearestNeighbor);
+		break
+	}
+
+}
+
+func ipThumbnail(img image.Image, maxWidth uint, maxHeight uint, interpolation string) image.Image {
+
+	switch interpolation {
+	case "Bilinear" :
+		return _nfntResize.Thumbnail(maxWidth, maxHeight, img, _nfntResize.Bilinear);
+		break
+	case "NearestNeighbor" :
+		return _nfntResize.Thumbnail(maxWidth, maxHeight, img, _nfntResize.NearestNeighbor);
+		break
+	case "Bicubic" :
+		return _nfntResize.Thumbnail(maxWidth, maxHeight, img, _nfntResize.Bicubic);
+		break
+	case "MitchellNetravali" :
+		return _nfntResize.Thumbnail(maxWidth, maxHeight, img, _nfntResize.MitchellNetravali);
+		break
+	case "Lanczos2" :
+		return _nfntResize.Thumbnail(maxWidth, maxHeight, img, _nfntResize.Lanczos2);
+		break
+	case "Lanczos3" :
+		return _nfntResize.Thumbnail(maxWidth, maxHeight, img, _nfntResize.Lanczos3);
+		break
+	default :
+		return _nfntResize.Thumbnail(maxWidth, maxHeight, img, _nfntResize.NearestNeighbor);
+		break
+	}
+
+}
+
+func ipFlip(img image.Image, axis string) image.Image {
+	switch axis {
+	case "Horizontal" :
+		return _bildTransform.FlipH(img)
+	case "Vertical" :
+		return _bildTransform.FlipV(img)
+	default :
+		return img
+	}
+}
+
+func ipRotate(img image.Image, angle float64) image.Image {
+	return _bildTransform.Rotate(img, angle, nil);
+}
+
+func ipShear(img image.Image, axis string, angle float64) image.Image {
+	switch axis {
+	case "Horizontal" :
+		return _bildTransform.ShearH(img, angle)
+	case "Vertical" :
+		return _bildTransform.ShearV(img, angle)
+	default :
+		return img
+	}
+}
+
+func ipTranslate(img image.Image, dx int, dy int) image.Image {
+	return _bildTransform.Translate(img, dx, dy)
+}
+
+// Image Adjustments
+
+func ipBrightness(img image.Image, change float64) image.Image {
+	return _bildAdjust.Brightness(img, change);
+}
+
+func ipContrast(img image.Image, change float64) image.Image {
+	return _bildAdjust.Contrast(img, change);
+}
+
+func ipGamma(img image.Image, gamma float64) image.Image {
+	return _bildAdjust.Gamma(img, gamma);
+}
+
+func ipHue(img image.Image, change int) image.Image {
+	return _bildAdjust.Hue(img, change);
+}
+
+func ipSaturation(img image.Image, change float64) image.Image {
+	return _bildAdjust.Saturation(img, change);
+}
+
+// Blend Modes
+
+func ipBlendMode(background image.Image, foreground image.Image, blendmode string) image.Image {
+	switch blendmode {
+	case "Add" :
+		return _bildBlend.Add(background, foreground)
+	case "ColorBurn" :
+		return _bildBlend.ColorBurn(background, foreground)
+	case "ColorDodge" :
+		return _bildBlend.ColorDodge(background, foreground)
+	case "Darken" :
+		return _bildBlend.Darken(background, foreground)
+	case "Difference" :
+		return _bildBlend.Difference(background, foreground)
+	case "Divide" :
+		return _bildBlend.Divide(background, foreground)
+	case "Exclusion" :
+		return _bildBlend.Exclusion(background, foreground)
+	case "Lighten" :
+		return _bildBlend.Lighten(background, foreground)
+	case "LinearBurn" :
+		return _bildBlend.LinearBurn(background, foreground)
+	case "LinearLight" :
+		return _bildBlend.LinearLight(background, foreground)
+	case "Multiply" :
+		return _bildBlend.Multiply(background, foreground)
+	case "Normal" :
+		return _bildBlend.Normal(background, foreground)
+	case "Overlay" :
+		return _bildBlend.Overlay(background, foreground)
+	case "Screen" :
+		return _bildBlend.Screen(background, foreground)
+	case "SoftLight" :
+		return _bildBlend.SoftLight(background, foreground)
+	case "Subtract" :
+		return _bildBlend.Subtract(background, foreground)
+	default :
+		return background
+	}
+}
+
+func ipBlendModeOpacity(background image.Image, foreground image.Image, percentage float64) image.Image {
+	return _bildBlend.Opacity(background, foreground, percentage)
+}
+
+// Blur
+
+func ipBlur(img image.Image, method string, radius float64) image.Image {
+	switch method {
+	case "Box" :
+		return _bildBlur.Box(img, radius)
+	case "Gaussian" :
+		return _bildBlur.Gaussian(img, radius)
+	default :
+		return img
+	}
+}
+
+// Channel Extraction
+
+func ipExtractChannel(img image.Image, chnl string) image.Image {
+	switch chnl {
+	case "Red" :
+		return _bildChannel.Extract(img, _bildChannel.Red)
+	case "Green" :
+		return _bildChannel.Extract(img, _bildChannel.Green)
+	case "Blue" :
+		return _bildChannel.Extract(img, _bildChannel.Blue)
+	case "Alpha" :
+		return _bildChannel.Extract(img, _bildChannel.Alpha)
+	default :
+		return img
+	}
+}
+
+// Painting
+
+func ipFloodFill(img image.Image, point [2]int, clr [4]uint8, fuzzy uint8) image.Image {
+
+	// help needed: struggling to provide a proper color RGBA to FloodFill
+
+	// lot of troubles with this function color.NRGBA - need help.
+	//return paint.FloodFill(img, image.Pt(point[0], point[1]), color.NRGBA(clr[0], clr[1], clr[2], clr[3]), fuzzy)
+	return img;
+}
+
+// Image Effects
+
+func ipDilate(img image.Image, radius float64) image.Image {
+	return _bildEffect.Dilate(img, radius);
+}
+
+func ipEdgeDetection(img image.Image, radius float64) image.Image {
+	return _bildEffect.Dilate(img, radius);
+}
+
+func ipEmboss(img image.Image) image.Image {
+	return _bildEffect.Emboss(img);
+}
+
+func ipErode(img image.Image, radius float64) image.Image {
+	return _bildEffect.Erode(img, radius);
+}
+
+func ipGrayscale(img image.Image) image.Image {
+	return _bildEffect.Grayscale(img);
+}
+
+func ipInvert(img image.Image) image.Image {
+	return _bildEffect.Invert(img);
+}
+
+func ipMedian(img image.Image, radius float64) image.Image {
+	return _bildEffect.Median(img, radius);
+}
+
+func ipSepia(img image.Image) image.Image {
+	return _bildEffect.Sepia(img);
+}
+
+func ipSharpen(img image.Image) image.Image {
+	return _bildEffect.Sharpen(img);
+}
+
+func ipSobel(img image.Image) image.Image {
+	return _bildEffect.Sobel(img);
+}
+
+func ipUnsharpMask(img image.Image, radius float64, amount float64) image.Image {
+	return _bildEffect.UnsharpMask(img, radius, amount);
+}
+

tpl/tplimpl/template_funcs.go

@@ -2134,6 +2134,37 @@ func (t *templateFuncster) initFuncMap() {
 		"index":         index,
 		"int":           func(v interface{}) (int, error) { return cast.ToIntE(v) },
 		"intersect":     intersect,
+		"ipOpen":        ipOpen,
+		"ipSave":        ipSave,
+		"ipCrop":        ipCrop,
+		"ipSmartCrop":   ipSmartCrop,
+		"ipResize":   	 ipResize,
+		"ipThumbnail":   ipThumbnail,
+		"ipFlip":   	 ipFlip,
+		"ipRotate":   	 ipRotate,
+		"ipShear":   	 ipShear,
+		"ipTranslate":	 ipTranslate,
+		"ipBrightness":  ipBrightness,
+		"ipContrast":    ipContrast,
+		"ipGamma":   	 ipGamma,
+		"ipHue":   	 ipHue,
+		"ipSaturation":  ipSaturation,
+		"ipBlendMode":   ipBlendMode,
+		"ipBlendModeOpacity":   ipBlendModeOpacity,
+		"ipBlur":   	 ipBlur,
+		"ipExtractChannel":   ipExtractChannel,
+		"ipFloodFill":   ipFloodFill,
+		"ipDilate":   	 ipDilate,
+		"ipEdgeDetection":   ipEdgeDetection,
+		"ipEmboss":   	 ipEmboss,
+		"ipErode":   	 ipErode,
+		"ipGrayscale":   ipGrayscale,
+		"ipInvert":   	 ipInvert,
+		"ipMedian":   	 ipMedian,
+		"ipSepia":   	 ipSepia,
+		"ipSharpen":   	 ipSharpen,
+		"ipSobel":   	 ipSobel,
+		"ipUnsharpMask": ipUnsharpMask,
 		"isSet":         isSet,
 		"isset":         isSet,
 		"jsonify":       jsonify,