Java Graphics - Kushal's Java Blog | Software Engineering Blog

Cropping An Image In Java [Sample/Tutorial With Source Code]

By Kushal Paudyal | June 9, 2013 - 1:42 pm | Java Graphics

Cropping refers to the removal of the outer parts of an image to improve framing, accentuate subject matter or change aspect ratio. Depending on the application, this may be performed on a physical photograph, artwork or film footage, or achieved digitally using image editing software. The term is common to the film, broadcasting, photographic, graphic design and printing industries.

In the printing, graphic design and photography industries, cropping refers to removing unwanted areas from a photographic or illustrated image. One of the most basic photo manipulation processes, it is performed in order to remove an unwanted subject or irrelevant detail from a photo, change its aspect ratio, or to improve the overall composition. In telephoto photography, most commonly in bird photography, an image is cropped to magnify the primary subject and further reduce the angle of view when a lens of sufficient focal length to achieve the desired magnification directly is not available. It is considered one of the few editing actions permissible in modern photojournalism along with tonal balance, colour correction and sharpening. A crop made from the top and bottom of a photograph may produce an aspect which mimics the panoramic format (in photography) and the widescreen format in cinematography and broadcasting. Both of these formats are not cropped as such, rather the product of highly specialised optical configuration and camera design. [Wikipedia]

The following picture shows the cropping are lying within the image.

The following image shows portions of cropping area lying outside the original image

The following program written in java show how image cropping can be done easily. The program takes an image and the cropping parameters as input.
Then it determines if the cropping area lies within the image or not. In case a cropping area in portion or fully lies outside the main image co-ordinates, the program adjusts the crop area.

The parameters used in the cropping are:
– Height of the cropping rectangle.
– Width of the cropping rectangle.
– X Co-ordinate of the start point of the cropping rectangle.
– Y Co-ordinate of the start point of the cropping rectangle.

The program also takes care of the negative co-ordinates supplied for the crop area rectangle.

Finally the program crops the input image and saves a copy of the cropped image.

You can find more comments int the java program itself.

package com.kushal.graphics;
/**
 * @Author Kushal Paudyal
 * www.sanjaal.com/java
 * Last Modified On 2009-10-08
 *
 * This utility crops an image with the provided
 * crop parameters (crop rectangle dimension and
 * rectangle start co-ordinates)
 */
import java.awt.Dimension;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import java.awt.image.RasterFormatException;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

public class ImageCropper {

static Rectangle clip;

public static void main(String args[]) throws Exception {
String inputFileLocation = "C:/temp/myImage02.jpg";
String outputFileLocation = "C:/temp/myImage-cropped.jpg";

System.out.println("Reading Original File : " + inputFileLocation);

BufferedImage originalImage = readImage(inputFileLocation);

/**
* Image Cropping Parameters
*/
int cropHeight = 150;
int cropWidth = 150;
int cropStartX = 50;
int cropStartY = 50;

BufferedImage processedImage = cropMyImage(originalImage, cropWidth,
cropHeight, cropStartX, cropStartY);

System.out.println("Writing the cropped image to: "
+ outputFileLocation);
writeImage(processedImage, outputFileLocation, "jpg");
System.out.println("...Done");
}

public static BufferedImage cropMyImage(BufferedImage img, int cropWidth,
int cropHeight, int cropStartX, int cropStartY) throws Exception {
BufferedImage clipped = null;
Dimension size = new Dimension(cropWidth, cropHeight);

createClip(img, size, cropStartX, cropStartY);

try {
int w = clip.width;
int h = clip.height;

System.out.println("Crop Width " + w);
System.out.println("Crop Height " + h);
System.out.println("Crop Location " + "(" + clip.x + "," + clip.y
+ ")");

clipped = img.getSubimage(clip.x, clip.y, w, h);

System.out.println("Image Cropped. New Image Dimension: "
+ clipped.getWidth() + "w X " + clipped.getHeight() + "h");
} catch (RasterFormatException rfe) {
System.out.println("Raster format error: " + rfe.getMessage());
return null;
}
return clipped;
}

/**
* This method crops an original image to the crop parameters provided.
*
* If the crop rectangle lies outside the rectangle (even if partially),
* adjusts the rectangle to be included within the image area.
*
* @param img = Original Image To Be Cropped
* @param size = Crop area rectangle
* @param clipX = Starting X-position of crop area rectangle
* @param clipY = Strating Y-position of crop area rectangle
* @throws Exception
*/
private static void createClip(BufferedImage img, Dimension size,
int clipX, int clipY) throws Exception {
/**
* Some times clip area might lie outside the original image,
* fully or partially. In such cases, this program will adjust
* the crop area to fit within the original image.
*
* isClipAreaAdjusted flas is usded to denote if there was any
* adjustment made.
*/
boolean isClipAreaAdjusted = false;

/**Checking for negative X Co-ordinate**/
if (clipX < 0) {
clipX = 0;
isClipAreaAdjusted = true;
}
/**Checking for negative Y Co-ordinate**/
if (clipY < 0) {
clipY = 0;
isClipAreaAdjusted = true;
}

/**Checking if the clip area lies outside the rectangle**/
if ((size.width + clipX) <= img.getWidth()
&& (size.height + clipY) <= img.getHeight()) {

/**
* Setting up a clip rectangle when clip area
* lies within the image.
*/

clip = new Rectangle(size);
clip.x = clipX;
clip.y = clipY;
} else {

/**
* Checking if the width of the clip area lies outside the image.
* If so, making the image width boundary as the clip width.
*/
if ((size.width + clipX) > img.getWidth())
size.width = img.getWidth() - clipX;

/**
* Checking if the height of the clip area lies outside the image.
* If so, making the image height boundary as the clip height.
*/
if ((size.height + clipY) > img.getHeight())
size.height = img.getHeight() - clipY;

/**Setting up the clip are based on our clip area size adjustment**/
clip = new Rectangle(size);
clip.x = clipX;
clip.y = clipY;

isClipAreaAdjusted = true;

}
if (isClipAreaAdjusted)
System.out.println("Crop Area Lied Outside The Image."
+ " Adjusted The Clip Rectangle\n");
}

/**
* This method reads an image from the file
*
* @param fileLocation -- >
*            eg. "C:/testImage.jpg"
* @return BufferedImage of the file read
*/
public static BufferedImage readImage(String fileLocation) {
BufferedImage img = null;
try {
img = ImageIO.read(new File(fileLocation));
System.out.println("Image Read. Image Dimension: " + img.getWidth()
+ "w X " + img.getHeight() + "h");
} catch (IOException e) {
e.printStackTrace();
}
return img;
}

/**
* This method writes a buffered image to a file
*
* @param img -- > BufferedImage
* @param fileLocation --> e.g. "C:/testImage.jpg"
* @param extension --> e.g. "jpg","gif","png"
*/
public static void writeImage(BufferedImage img, String fileLocation,
String extension) {
try {
BufferedImage bi = img;
File outputfile = new File(fileLocation);
ImageIO.write(bi, extension, outputfile);
} catch (IOException e) {
e.printStackTrace();
}
}

/*
* SANJAAL CORPS MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE
* SUITABILITY OF THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT
* LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE, OR NON-INFRINGEMENT. SANJAAL CORPS SHALL NOT BE
* LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING,
* MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
*
* THIS SOFTWARE IS NOT DESIGNED OR INTENDED FOR USE OR RESALE AS ON-LINE
* CONTROL EQUIPMENT IN HAZARDOUS ENVIRONMENTS REQUIRING FAIL-SAFE
* PERFORMANCE, SUCH AS IN THE OPERATION OF NUCLEAR FACILITIES, AIRCRAFT
* NAVIGATION OR COMMUNICATION SYSTEMS, AIR TRAFFIC CONTROL, DIRECT LIFE
* SUPPORT MACHINES, OR WEAPONS SYSTEMS, IN WHICH THE FAILURE OF THE
* SOFTWARE COULD LEAD DIRECTLY TO DEATH, PERSONAL INJURY, OR SEVERE
* PHYSICAL OR ENVIRONMENTAL DAMAGE ("HIGH RISK ACTIVITIES"). SANJAAL CORPS
* SPECIFICALLY DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR
* HIGH RISK ACTIVITIES.
*/

}

Here is the output of this program:

Reading Original File : C:/temp/myImage02.jpg
Image Read. Image Dimension: 200w X 370h
Crop Width 150
Crop Height 150
Crop Location (50,50)
Image Cropped. New Image Dimension: 150w X 150h
Writing the cropped image to: C:/temp/myImage-cropped.jpg
...Done

Here is the original Picture:

Here is the picture cropped by the program above.

Originally posted 2009-10-08 16:14:53.

Converting An Colored Image To A Gray Scale Using Java Graphics 2D [Example Code]

By Kushal Paudyal | May 29, 2013 - 8:14 pm | Java Graphics

1 Comment

In photography and computing, a grayscale or greyscale digital image is an image in which the value of each pixel is a single sample, that is, it carries only intensity information. Images of this sort, also known as black-and-white, are composed exclusively of shades of gray, varying from black at the weakest intensity to white at the strongest.

Grayscale images are distinct from one-bit black-and-white images, which in the context of computer imaging are images with only the two colors, black, and white (also called bilevel or binary images). Grayscale images have many shades of gray in between. Grayscale images are also called monochromatic, denoting the absence of any chromatic variation.

Grayscale images are often the result of measuring the intensity of light at each pixel in a single band of the electromagnetic spectrum (e.g. infrared, visible light, ultraviolet, etc.), and in such cases they are monochromatic proper when only a given frequency is captured. But also they can be synthesized from a full color image; see the section about converting to grayscale. [Wikipedia/Creative Commons Attribution-ShareAlike License]

In the following java program, we will:

Read an Image from the disk location
Convert the image to gray scale
Write the grayed out image back to the disk

Stewie Griffin is my favorite character from Seth MacFarlane’s animated TV Series “The Family Guy”. I have used Stewie’s image for the gray scale conversion example. The credit of the image goes to it’s original author.

package com.kushal.graphics;
/**
 * @Author Kushal Paudyal
 * www.sanjaal.com/java
 * Last Modified On: 2009-09-28
 * 
 * Utility to convert a colored image into gray color.
 */
import java.awt.color.ColorSpace;
import java.awt.image.BufferedImage;
import java.awt.image.ColorConvertOp;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

public class GrayMyImage {

	public static void main(String args[]) {
		GrayMyImage imageGrayer = new GrayMyImage();
		String inputImageFilePath="C:/temp/myImage.jpg";
		String outputImageFilePath="C:/temp/myImage-grayedout.jpg";
		
		System.out.println("Reading input image...");
		BufferedImage inputImage = imageGrayer.readImage(inputImageFilePath);
		System.out.println("Successfully Read Image: "+inputImageFilePath);

		System.out.println("\nConverting the image to Gray colors.");
		BufferedImage grayedOut = imageGrayer.grayOut(inputImage);
		System.out.println("Successful...");

		System.out.println("\nWriting gray image to filesystems.");
		imageGrayer.writeImage(grayedOut,outputImageFilePath , "jpg");
		System.out.println("Successfully Wrote Image To: "+outputImageFilePath);
	}
	
	/**
	 * This method converts any input BufferedImage
	 * object to the gray color and returns it.
	 */
	public BufferedImage grayOut(BufferedImage img) {
		ColorConvertOp colorConvert = new ColorConvertOp(ColorSpace
				.getInstance(ColorSpace.CS_GRAY), null);
		colorConvert.filter(img, img);

		return img;
	}

	/**
	 * This method reads an image from the file
	 * @param fileLocation -- > eg. "C:/testImage.jpg"
	 * @return BufferedImage of the file read
	 */
	public BufferedImage readImage(String fileLocation) {
		BufferedImage img = null;
		try {
			img = ImageIO.read(new File(fileLocation));
		} catch (IOException e) {
			e.printStackTrace();
		}
		return img;
	}

	/**
	 * This method writes a buffered image to a file
	 * @param img -- > BufferedImage
	 * @param fileLocation --> e.g. "C:/testImage.jpg"
	 * @param extension --> e.g. "jpg","gif","png"
	 */
	public void writeImage(BufferedImage img, String fileLocation,
			String extension) {
		try {
			BufferedImage bi = img;
			File outputfile = new File(fileLocation);
			ImageIO.write(bi, extension, outputfile);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

Output of the program:

Reading input image...
Successfully Read Image: C:/temp/myImage.jpg

Converting the image to Gray colors.
Successful...

Writing gray image to filesystems.
Successfully Wrote Image To: C:/temp/myImage-grayedout.jpg

Original Input Image:

Image Grayed Out By The Program Above:

Originally posted 2009-09-28 10:06:57.

Category Archives: Java Graphics

Cropping An Image In Java [Sample/Tutorial With Source Code]

Converting An Colored Image To A Gray Scale Using Java Graphics 2D [Example Code]

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