source: trunk/grails-app/utils/Imaging.groovy @ 182

import java.awt.AlphaComposite
import java.awt.Color
import java.awt.Graphics2D
import java.awt.geom.AffineTransform
import java.awt.geom.Rectangle2D
import java.awt.image.AffineTransformOp
import java.awt.image.BufferedImage
import java.io.ByteArrayInputStream
import java.io.ByteArrayOutputStream
import javax.imageio.ImageIO

class Imaging {

    static def createAll(InventoryItem inventoryItem, Picture picture, InputStream stream) {
        BufferedImage original = ImageIO.read(stream)
        picture.contentType = 'image/jpeg'
        picture.width = original.width
        picture.height = original.height
        def images = [ 
            new Image(inventoryItem: inventoryItem, picture: picture, size: Image.Original),
            new Image(inventoryItem: inventoryItem, picture: picture, size: Image.Large),
            new Image(inventoryItem: inventoryItem, picture: picture, size: Image.Medium),
            new Image(inventoryItem: inventoryItem, picture: picture, size: Image.Small)
            ]
        ByteArrayOutputStream output = new ByteArrayOutputStream(1024 * 1024)
        updateImages(images, original, output)
        images
    }
    
    static def updateAll(Picture picture) {
        def operation = picture.operation
        if (operation == Picture.NoOp) {
            return null
        }
        def images = picture.images.toArray() // Image.findAllByPicture(picture, [ sort: 'size', order: 'asc' ])
        BufferedImage original = ImageIO.read(new ByteArrayInputStream(images[0].data))
        AffineTransform transform = new AffineTransform();
        def op = null
        boolean paint = false
        Integer width = original.width
        Integer height = original.height
        switch (operation) {
            case Picture.RotateClockWise90:
                transform.rotate(Math.PI / 2.0)
                transform.translate(0, -height)
                op = new AffineTransformOp(transform, AffineTransformOp.TYPE_BILINEAR);
                width = original.height
                height = original.width
                paint = true
                break
            case Picture.RotateAntiClockWise90:
                transform.rotate(-Math.PI / 2.0)
                transform.translate(-width, 0)
                op = new AffineTransformOp(transform, AffineTransformOp.TYPE_BILINEAR);
                width = original.height
                height = original.width
                paint = true
                break
            case Picture.Rotate180:
                transform.rotate(Math.PI)
                transform.translate(-width, -height)
                op = new AffineTransformOp(transform, AffineTransformOp.TYPE_BILINEAR);
                break
            case Picture.Flip: // vertical
                transform.scale(-1.0d, 1.0d)
                transform.translate(-width, 0)
                op = new AffineTransformOp(transform, AffineTransformOp.TYPE_NEAREST_NEIGHBOR)
                break
            case Picture.Flop: // horizontal
                transform.scale(1.0d, -1.0d)
                transform.translate(0, -height)
                op = new AffineTransformOp(transform, AffineTransformOp.TYPE_NEAREST_NEIGHBOR)
                break
            default:
                return images
                break
        }
        BufferedImage modified = op.filter(original, null);
        if (paint) {
            BufferedImage changed = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB)
            Graphics2D graphics = changed.createGraphics()
            graphics.drawImage(modified, 0, 0, width, height, null)
            graphics.dispose()
            modified = changed
            picture.width = width
            picture.height = height
        }
        ByteArrayOutputStream output = new ByteArrayOutputStream(1024 * 1024)
        updateImages(images, modified, output)
        images
    }

    private static def updateImages(images, original, stream) {
        updateImage(images[0], original, 'jpeg', stream)
        def large = resizeImage(original, dimensions(Image.Large), false)
        updateImage(images[1], large, 'png', stream)
        updateImage(images[2], resizeImage(large, dimensions(Image.Medium), true), 'png', stream)
        updateImage(images[3], resizeImage(large, dimensions(Image.Small), true), 'png', stream)
    }

    private static def updateImage(image, data, format, stream) {
        image.contentType = "image/${format}"
        image.width = data.width
        image.height = data.height
        stream.reset()
        if (!ImageIO.write(data, format, stream)) {
            throw new IOException("Can't write the image in the given format '${format}'")
        }
        image.data = stream.toByteArray()
    }

    private static def dimensions(size) {
        [ Image.Widths[size], Image.Heights[size] ]
    }    

    private static def resizeImage(imageBuffer, dims, fit) {
        Integer width = dims[0]
        Integer height = dims[1]
        Integer imageWidth = imageBuffer.width
        Integer imageHeight = imageBuffer.height
      
        Double widthScale = (double)width / (double)imageWidth
        Double heightScale = (double)height / (double)imageHeight
        BufferedImage resizedImage = imageBuffer
        if (widthScale < 1.0d || heightScale < 1.0d) {
            Double scale = Math.min(widthScale, heightScale)
            def transform = new AffineTransform()
            transform.scale(scale, scale)
            def op = new AffineTransformOp(transform, AffineTransformOp.TYPE_BILINEAR)
            resizedImage = op.filter(imageBuffer, null)
            imageWidth = resizedImage.width
            imageHeight = resizedImage.height
        }

        if (fit && (imageWidth < width || imageHeight < height)) {
            BufferedImage fittedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB)
            Integer left = (width - imageWidth) / 2
            Integer top = (height - imageHeight) / 2
            Graphics2D graphics = fittedImage.createGraphics()
            graphics.setComposite(AlphaComposite.getInstance(AlphaComposite.CLEAR, 0.0f))
            graphics.fill(new Rectangle2D.Double(0, 0, width, height))
            graphics.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 1.0f))
            graphics.drawImage(resizedImage, left, top, imageWidth, imageHeight, null)
            graphics.dispose()
            return fittedImage
        }
        resizedImage
    }
}