doc: add example

example_test.go

@@ -0,0 +1,58 @@
+package imaging_test
+
+import (
+	"image"
+	"image/color"
+	"log"
+
+	"github.com/disintegration/imaging"
+)
+
+func Example() {
+	// Open the test image.
+	src, err := imaging.Open("testdata/lena_512.png")
+	if err != nil {
+		log.Fatalf("Open failed: %v", err)
+	}
+
+	// Crop the original image to 350x350px size using the center anchor.
+	src = imaging.CropAnchor(src, 350, 350, imaging.Center)
+
+	// Resize the cropped image to width = 256px preserving the aspect ratio.
+	src = imaging.Resize(src, 256, 0, imaging.Lanczos)
+
+	// Create a blurred version of the image.
+	img1 := imaging.Blur(src, 2)
+
+	// Create a grayscale version of the image with higher contrast and sharpness.
+	img2 := imaging.Grayscale(src)
+	img2 = imaging.AdjustContrast(img2, 20)
+	img2 = imaging.Sharpen(img2, 2)
+
+	// Create an inverted version of the image.
+	img3 := imaging.Invert(src)
+
+	// Create an embossed version of the image using a convolution filter.
+	img4 := imaging.Convolve3x3(
+		src,
+		[9]float64{
+			-1, -1, 0,
+			-1, 1, 1,
+			0, 1, 1,
+		},
+		nil,
+	)
+
+	// Create a new image and paste the four produced images into it.
+	dst := imaging.New(512, 512, color.NRGBA{0, 0, 0, 0})
+	dst = imaging.Paste(dst, img1, image.Pt(0, 0))
+	dst = imaging.Paste(dst, img2, image.Pt(0, 256))
+	dst = imaging.Paste(dst, img3, image.Pt(256, 0))
+	dst = imaging.Paste(dst, img4, image.Pt(256, 256))
+
+	// Save the resulting image using JPEG format.
+	err = imaging.Save(dst, "testdata/out_example.jpg")
+	if err != nil {
+		log.Fatalf("Save failed: %v", err)
+	}
+}