DZone Snippets: graphics code

Patchwork quilt pattern in Ruby (from Knuth TAoCP 4 - 7.1.3)

peter (Peter Cooperx) — Wed, 27 Feb 2008 10:17:32 GMT

In Donald Knuth's TAoCP Pre-Fascicle 1a: Bitwise Tricks and Techniques, he shows a patchwork quilt defined by f(x, y) = ((x ^ y) & ((y - 350) >> 3)) ** 2, designed by D. Sleator in 1976. I wanted to recreate this quilt myself using Ruby. The following program generates a PNG file of the "quilt."



require 'rubygems'

require 'png'



def f(x, y)

  ( (x ^ y) & ((y - 350) >> 3) ) ** 2

end



canvas = PNG::Canvas.new(500, 500)



0.upto(499) do |y|

  0.upto(499) do |x|

    canvas[x, 499 - y] = ((f(x, y) >> 12) & 1) == 1 ? PNG::Color::Black : PNG::Color::White

  end

end



png = PNG.new(canvas)

png.save 'pattern.png'

Java - JFreeChart Example

whitetiger () — Wed, 01 Nov 2006 19:03:27 GMT



import java.awt.Font;



import javax.swing.JFrame;

import javax.swing.JPanel;



import org.jfree.chart.ChartFactory;

import org.jfree.chart.ChartPanel;

import org.jfree.chart.JFreeChart;

import org.jfree.chart.plot.PiePlot;

import org.jfree.data.general.DefaultPieDataset;



public class jfcExample extends JFrame

{

	private static final long serialVersionUID = 1L;

	

	private DefaultPieDataset dataset;

	private JFreeChart jfc;



	public jfcExample()

	{

		dataset = new DefaultPieDataset();

	}

	

	public void setValue(String title, Double numDouble)

	{

		dataset.setValue(title, numDouble);

	}

	

	public void setChar(String title)

	{

		jfc = ChartFactory.createPieChart(title, dataset, true, true, false);

		

		PiePlot pp = (PiePlot) jfc.getPlot();

		pp.setSectionOutlinesVisible(false);

		pp.setLabelFont(new Font("SansSerif", Font.PLAIN, 12));

		pp.setNoDataMessage("Nessun Dato Inserito");

		pp.setCircular(false);

		pp.setLabelGap(0.02);

	}

	

	private JPanel createPanel()

	{

		return new ChartPanel(jfc);

	}

	

	public void Show()

	{

		setContentPane(createPanel());

		setVisible(true);

	}

	

	public static void main(String[] args)

	{

		jfcExample j = new jfcExample();

		j.setTitle("Example Chart...");

		j.setSize(640, 430);

		

		j.setValue("UNO", new Double(20.0));

		j.setValue("DUE", new Double(10.0));

		j.setValue("TRE", new Double(20.0));

		j.setValue("QUATTRO", new Double(30.0));

		j.setValue("CINQUE", new Double(20.0));

		

		j.setChar("Example Chart...");

		

		j.Show();

	}

}

image resize

evitiello (Eric Vitiello) — Wed, 20 Jul 2005 21:53:09 GMT

This function will resize any input file restricting the width and height to be no more than the specified pixels, and output a binary stream.

function resize_jpg($inputFilename, $new_side){

	$imagedata = getimagesize($inputFilename);

	$w = $imagedata[0];

	$h = $imagedata[1];

	

	if ($h > $w) {

		$new_w = ($new_side / $h) * $w;

		$new_h = $new_side;	

	} else {

		$new_h = ($new_side / $w) * $h;

		$new_w = $new_side;

	}

	

	$im2 = ImageCreateTrueColor($new_w, $new_h);

	$image = ImageCreateFromJpeg($inputFilename);

	imagecopyResampled ($im2, $image, 0, 0, 0, 0, $new_w, $new_h, $imagedata[0], $imagedata[1]);

	return $im2;

}

Installing libjpeg on OS X

peter (Peter Cooperx) — Tue, 05 Apr 2005 20:21:21 GMT

Get http://www.ijg.org/files/jpegsrc.v6b.tar.gz, and then:

tar zxvf jpegsrc.v6b.tar.gz

cd jpeg-6b

cp /usr/share/libtool/config.sub .

cp /usr/share/libtool/config.guess .

./configure --enable-shared --enable-static

make

sudo make install

sudo ranlib /usr/local/lib/libjpeg.a

Thumbnailer in Ruby and RMagick

peter (Peter Cooperx) — Mon, 04 Apr 2005 06:41:44 GMT

require 'RMagick'



maxwidth = 120

maxheight = 160

aspectratio = maxwidth.to_f / maxheight.to_f

imgfile = 'world'



pic = Magick::Image.read(imgfile + '.jpg').first

imgwidth = pic.columns

imgheight = pic.rows

imgratio = imgwidth.to_f / imgheight.to_f

imgratio > aspectratio ? scaleratio = maxwidth.to_f / imgwidth : scaleratio = maxheight.to_f / imgheight

thumb = pic.resize(scaleratio)



white_bg = Magick::Image.new(maxwidth, thumb.height)

pic = white_bg.composite(thumb, Magick::CenterGravity, Magick::OverCompositeOp)

pic.write(imgfile + '.thumb.jpg')