main.cpp File Reference

A simple C++ program that manipulates an image. More...

#include <algorithm>
#include <iostream>
#include "rgbapixel.h"
#include "png.h"

Functions
PNG	drawCrosshairs (PNG original, int centerX, int centerY, RGBAPixel color)
	This function accepts a PNG object, two integer coordinates and a color, and proceeds to draw a horizontal line across the image at the y coordinate and a vertical line down the image at the x coordinage using the given color. More...
PNG	brighten (PNG original, int amount)
	This function brightens a rectangle of a PNG, increasing the components (red, green, blue) of each pixel by the given amount. More...
PNG	blendImages (PNG firstImage, PNG secondImage)
	This function blends, or averages, two PNGs together. More...
int	main ()
	The main function in this program (the starting point of the execution of our code). More...

Detailed Description

A simple C++ program that manipulates an image.

Function Documentation

PNG drawCrosshairs	(	PNG	original,
		int	centerX,
		int	centerY,
		RGBAPixel	color
	)

This function accepts a PNG object, two integer coordinates and a color, and proceeds to draw a horizontal line across the image at the y coordinate and a vertical line down the image at the x coordinage using the given color.

The modified PNG is then returned.

Parameters

original	A PNG object which holds the image data to be modified.
centerX	The center x coordinate of the crosshair which is to be drawn.
centerY	The center y coordinate of the crosshair which is to be drawn.
color	The color of the lines to be drawn.

Returns

The image on which a crosshair has been drawn.

This function is already written for you so you can see how to interact with our PNG class.

PNG brighten	(	PNG	original,
		int	amount
	)

This function brightens a rectangle of a PNG, increasing the components (red, green, blue) of each pixel by the given amount.

You must account for potential overflow issues (color components can only store numbers between 0 and 255). If you attempt to store a value greater than 255 into a color component, the result will wrap around (and you won't be able to check if it was greater than 255).

Parameters

original	A PNG object which holds the image data to be modified.
amount	The integer amount by which to increase each pixel's components.

Returns

The brightened image.

You can assume amount is positive.

PNG blendImages	(	PNG	firstImage,
		PNG	secondImage
	)

This function blends, or averages, two PNGs together.

That is, each pixel in the returned image consists of the averaged components (red, green, blue) of the two input images.

Parameters

firstImage	The first of the two PNGs to be averaged together.
secondImage	The second of the two PNGs to be averaged together.

Returns

The averaged image.

int main

(

)

The main function in this program (the starting point of the execution of our code).

Returns

An integer indicating whether execution was successful.