Jeremy of all Trades Home » Archive by category 'Coding » Groovy'

A while back, I started playing around with Google App Engine (Java) and the lightweight, Groovy , Gaelyk. There’s also a great library written for using the low level datastore in App Engine called Objectify.

I decided to write a little Groovified wrapper for Objectify (which already does most of the work) and turn it into a plugin for Gaelyk. It adds a little syntactic sugar, and although it doesn’t have everything, it is working nicely for me so far. Check out the Obgaektify site to learn more.

Put this script in a particular directory (or change the directory specified in startDir variable
and it will recurse through all sub-directories, creating thumbnails of the images (jpg, png, gif, or bmp).
If you change the deleteOriginal variable to true, it will delete the original image for you afterwards.

import javax.imageio.*
import java.awt.*;
import java.awt.image.*;

def startDir = new File(".")
def deleteOriginal = false
def thumbWidth = 200
def thumbHeight = 150

startDir.eachFileRecurse{file->
	if(file.name =~ /\.(JPG|jpg|PNG|png|GIF|gif|BMP|bmp)$/)
	{
		def imgType = file.name.replaceAll(/[^\.]*\.(JPG|jpg|PNG|png|GIF|gif|BMP|bmp)$/, "\$1")
		def imgPath = file.getCanonicalPath().replaceAll(/\.(JPG|jpg|PNG|png|GIF|gif|BMP|bmp)$/, "_Thumb.\$1")
		println("$imgType, $imgPath")

		//load each image
		img = ImageIO.read(file)
		println (file.name + " " + img.width + "x" + img.height)

		//output scaled thumbnail image
		width = thumbWidth
		height = thumbHeight
		if(img.width < img.height){width = thumbHeight; height = thumbWidth;}
		BufferedImage thumbImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		Graphics2D gThumbImg = thumbImg.createGraphics();
		gThumbImg.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
		gThumbImg.drawImage(img, 0, 0, width, height, null);
		ImageIO.write(thumbImg, "$imgType", new File(imgPath))

		if(deleteOriginal)
		{
			file.delete()
		}
	}
}

It took a little while for me to track down how to read and write Unicode-encoded files using Groovy. Here’s the answer:

 /*
Given a file called test.txt that's filled with text in UTF-8 format,
here's how to use Groovy to read it in, preserve the encoding, and
output it to a file called testout.txt, also in UTF-8 formatting.
*/
def inF = new File("test.txt")
def reader = inF.newReader("UTF-8")
def outF = new File("testout.txt")
outF.withWriter("UTF-8"){writer->
    reader.eachLine{line->
        writer.write(line)
    }
}

//Groovy script that demonstrates dynamically adding and removing text fields from a Swing form

import groovy.swing.SwingBuilder

swing = new SwingBuilder()

addButton = swing.button(text: 'Add Field', actionPerformed: {addField()})
remButton = swing.button(text: 'Remove Field', actionPerformed: {removeField()})

frame = swing.frame(title:"Test Dynamic Fields", size: [200,400], defaultCloseOperation:javax.swing.WindowConstants.EXIT_ON_CLOSE)
{
	panel = panel()
	{
		vbox = vbox(id:'vbox')
		{
			hbox()
			{
				widget(addButton)
				widget(remButton)
			}
		}
	}
}

fields = []
fields << swing.textField(text: fields.size())

vbox.add(fields[0])

//frame.pack()
frame.show()

def addField()
{
	field = swing.textField(text: fields.size())
	fields << field
	vbox.add(field)
	vbox.revalidate()
}

def removeField()
{
	if(fields.size() > 0)
	{
		field = fields[-1]
		vbox.remove(field)
		fields.remove(fields.size() - 1)
	}
	vbox.revalidate()
}