Thread: Image manipulation program help

Hi. Beginner here. I have a question about a Java program on manipulation of photos.

I want to learn how to rotate a photo 90 degrees, rotate it 180 degrees, enlarge it by doubling its width and length, and stitching them.

So far I have written a code segment on how to copy a photo:

public class PhotoTools {


public static Photograph copy(Photograph photo) {


Photograph copy_of_photo = new Photograph(photo.getWidth(), photo.getHeight()); /*create a new photo and get dimensions*/

for (int row = 0; row < photo.getWidth(); row++){ //2 loops going through each column then row
for (int col = 0; col < photo.getHeight(); col++){
Pixel copy = photo.getPixel(row, col); //set pixels to get the pixels in the photo
copy_of_photo.setPixel(row, col, copy); //copy pixels to new photo
}

}
return copy_of_photo; //return new copied photo
}

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Please do not give me actual code.
I was hoping I could get hints on ways to approach the other methods.

Thank you for your time.

I am using a custom class created by someone.

Photograph Class

Constructor Summary
Photograph(int width, int height)
Create a blank photo of a specified size.

Method Summary

int getHeight()
Access height of photo.

Pixel getPixel(int x, int y)
Access one of the Pixels in the photo.

int getWidth()
Access width of photo.

void setPixel(int x, int y, Pixel p)
Set one of the Pixels in the photo.


Constructor Detail
Photograph

public Photograph(int width,int height)
Create a blank photo of a specified size.

Method Detail
getWidth

public int getWidth()
Access width of photo.
Returns:
width (in pixels)

getHeight

public int getHeight()
Access height of photo.
Returns:
height (in pixels)

getPixel
public Pixel getPixel(int x,int y)
Access one of the Pixels in the photo.
Parameters:
x - x-coordinate of desired pixel
y - y-coordinate of desired pixel
Returns:
Pixel at position (x, y) in the photograph. Note that the origin (0, 0) is located at the upper left corner of the photo.


setPixel

public void setPixel(int x,int y,Pixel p)
origin (0, 0) is located at the upper left corner of the photo.



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Class Pixel (class that represents a single pixel in a photograph)

Constructor Summary
Pixel(int red, int green, int blue)
Create a new Pixel object by specifying the levels of red, green, and blue colors present.


Method Summary
int getBlue()
Returns the level of blue seen in the Pixel
int getGreen()
Returns the level of green seen in the Pixel
int getRed()
Returns the level of red seen in the Pixel




Method Detail
getRed

public int getRed()
Returns the level of red seen in the Pixel
Returns:
level of red (0 to 255)


getGreen

public int getGreen()
Returns the level of green seen in the Pixel
Returns:
level of green (0 to 255)


getBlue

public int getBlue()
Returns the level of blue seen in the Pixel
Returns:
level of blue (0 to 255)

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--- Update ---

These packages were created by my teacher and I own nothing. I was hoping for tips or hints on how I can rotate 90/180 degrees, stitch, enlarge or some insight on how to think about this problem. Thanks.

Here is what I have so far for stretch. The user will input 0 or 1 in the driver.
---------------------------------------------------------

public static Photograph stretched(Photograph photo, int type) {
 
		// In other words, 
		//if type is 0, then each column of pixels in the original photo will appear twice in the new one.  
		//If type is 1, then each row in the original photo will appear twice in the new one.
 
		//0 = horizontal stretch
		// 1 = vertical stretch
		Photograph stretched_photo = new Photograph(photo.getWidth(), photo.getHeight());
 
 
 
		if (type == 0){
 
			Photograph horizontal_stretch = new Photograph (2*photo.getWidth(), photo.getHeight());
 
			for (int row = 0; row < photo.getWidth(); row++){
				for (int col = 0; col< photo.getHeight(); col++){
 
					Pixel p = photo.getPixel(row, col);
					horizontal_stretch.setPixel(row, col, p);
					horizontal_stretch.setPixel(row, col, p);
				}
 
			}
		    stretched_photo.equals(horizontal_stretch);   
			return stretched_photo;
		}
 
		else if (type == 1){
 
			Photograph vertical_stretch = new Photograph (photo.getWidth(), 2*photo.getHeight());
 
			for (int row = 0; row < photo.getWidth(); row++){
				for (int col = 0; col< photo.getHeight(); col++){
 
					Pixel p = photo.getPixel(row, col);
					vertical_stretch.setPixel(row, col, p);
				    vertical_stretch.setPixel(++row, col, p);
				}
 
			}
			 stretched_photo.equals(vertical_stretch);  
		       return vertical_stretch;
		}
 
		return stretched_photo;
	}

Thanks for your help. Do you have any hints as to how I would go about approaching rotating an image or enlarging it.
For rotating 90 degrees i know the new Column = row and new_Row = col. And 180 degrees is just a copy but upside down. Not sure how to set pixels for that. For enlarging I'm having trouble duplicating an extra column or row for horizontal and vertical stretch respectively. I would imagine it's the same as copy but I set pixels twice.
Any hints or ideas would help.

In the prompt, I have to try and duplicate an extra column or row.

For Horizontal stretch I have to duplicate an extra column...So in instead of have (for first row) {(0,0), (0,1), (0,2), (0,3)} I have to make it {(0,0),(0,0),(0,1),(0,1),(0,2),(0,2),(0,3),(0,3)}

Same for the vertical stretch except I duplicate a row in each pixel/ grid...

I just dont't know how

I have to enlarge the whole image... if I understand row then i can get column (same concept)

For horizontal stretch..I have to duplicated the column of each pixel in a photo.
For vertical stretch..I have to duplicate the row of each pixel in a photo

Im having trouble understanding how to duplicate...I know how to copy an image. Im guessing I need to tweak that method but I dunno how to set pixels for the new duplicate after I've made it.