CS 3005: Programming in C++

Overloaded Operators

This assignment requires extending the text-based application for working with PPM images. The user will now be able to add two images, take their difference, and multiple or divide them by a number.

The result will be the ability to blend two images, and to change the overall brightness of an image.

Assignment

In this assignment, you will update the ppm_menu program from the previous assignments. All of the previous assignments’ functionality will remain intact.

Programming Requirements

The following files must be updated or created and stored in the src directory of your repository.

Make changes as described below.

Update PPM.{h,cpp}

The following methods must be added to the PPM class declaration in PPM.h and implemented in PPM.cpp.

• bool operator==( const PPM& rhs ) const; Returns true if *this has the same number of pixels as rhs. Otherwise returns false.
• bool operator!=( const PPM& rhs ) const; Returns true if *this has a different number of pixels than rhs. Otherwise returns false.
• bool operator<( const PPM& rhs ) const; Returns true if *this has a fewer number of pixels than rhs. Otherwise returns false.
• bool operator<=( const PPM& rhs ) const; Returns true if *this has a fewer number of pixels than rhs or equal number of pixels. Otherwise returns false.
• bool operator>( const PPM& rhs ) const; Returns true if *this has a greater number of pixels than rhs. Otherwise returns false.
• bool operator>=( const PPM& rhs ) const; Returns true if *this has a greater number of pixels than rhs or equal number of pixels. Otherwise returns false.
• PPM& operator+=( const PPM& rhs ); Assumes *this and rhs have the same width and height. Adds the channel values from rhs into the channels for *this. If the resulting value is larger than max color value, set to max color value. Returns *this.
• PPM& operator-=( const PPM& rhs ); Assumes *this and rhs have the same width and height. Subtracts the channel values from rhs from the channels for *this. If the resulting value is less than 0, set to 0. Returns *this.
• PPM& operator*=( const double& rhs ); Multiples every channel value of *this by rhs. If the resulting value is larger than max color value, set to max color value. If the resulting value is less than 0, set to 0. Returns *this.
• PPM& operator/=( const double& rhs ); Divides every channel value of *this by rhs. If the resulting value is larger than max color value, set to max color value. If the resulting value is less than 0, set to 0. Returns *this.
• PPM operator+( const PPM& rhs ) const; Creates a new PPM object with the same meta data (height, width, max color value) as *this. Sets the channel values in the new object to the sum of the channel values for *this and rhs. If the value is greater than max color value, set to max color value. Returns the new object.
• PPM operator-( const PPM& rhs ) const; Creates a new PPM object with the same meta data (height, width, max color value) as *this. Sets the channel values in the new object to the difference of the channel values for *this and rhs. If the value is less than 0, set to 0. Returns the new object.
• PPM operator*( const double& rhs ) const; Creates a new PPM object with the same meta data (height, width, max color value) as *this. Sets the channel values in the new object to the product of the channel values for *this and the value of rhs. If the value is greater than max color value, set to max color value. If the value is less than 0, set to 0. Returns the new object.
• PPM operator/( const double& rhs ) const; Creates a new PPM object with the same meta data (height, width, max color value) as *this. Sets the channel values in the new object to the division of the channel values of *this and by the value of rhs. If the value is greater than max color value, set to max color value. If the value is less than 0, set to 0. Returns the new object.

Update image_menu.h add image_filters.cpp

Implement the following functions in a new file image_filters.cpp. Put the declarations in image_menu.h. The functions should use input image 1 as the left hand operand. If the right hand operand is a PPM object, use input image 2. If the right hand operand is a numeric value, use getDouble to ask the user for the value to use. If the operator does not change the left hand operand, assign the result into the output image.

• void plusEquals( ActionData& action_data ); Modifies input image 1 by adding input image 2 to it.
• void minusEquals( ActionData& action_data ); Modifies input image 1 by subtracting input image 2 from it.
• void timesEquals( ActionData& action_data ); Modifies input image 1 by multiplying it by the double obtained by calling getDouble with a prompt of “Factor? “.
• void divideEquals( ActionData& action_data ); Modifies input image 1 by dividing it by the double obtained by calling getDouble with a prompt of “Factor? “.
• void plus( ActionData& action_data ); Sets output image to be the sum of input image 1 and input image 2.
• void minus( ActionData& action_data ); Sets output image to be the difference of input image 1 and input image 2.
• void times( ActionData& action_data ); Sets output image to input image1 times the double obtained by calling getDouble with a prompt of “Factor? “.
• void divide( ActionData& action_data ); Sets output image to input image 1 divided by the double obtained by calling getDouble with a prompt of “Factor? “.

Update image_menu.h and image_output.cpp

• void readUserImage2( ActionData& action_data ); Like readUserImage1, but stores into input image 2.

Update controllers.cpp

The following functions will require updates to their implementations.

• void configureMenu( MenuData& menu_data ) add the new actions with the names and descriptions listed below.

Table of New Commands

Update Makefile

This file must now also include a rule for clean. The following commands should work correctly.

• make hello - builds the hello program
• make questions_3 - builds the questions_3 program
• make ascii_image - builds the ascii_image program
• make image_file - builds the image_file program
• make ppm_menu - builds the image_file program
• make all - builds all programs
• make - builds all programs (same as make all)
• make clean - removes all .o files, and all executable programs

Additional Documentation

• C++ Reference
• Examples from class
• Digital Image Processing on Wikipedia

Sample PPM Images

• Monet’s Lilies
• Van Gogh’s Starry Night
• Monet + Van Gogh
• Monet - Van Gogh
• Monet *= 1.5
• Van Gogh /= 2.0

Show Off Your Work

To receive credit for this assignment, you must

• use git to add, commit and push your solution to your repository for this class.
• successfully pass all unit tests and acceptance tests

Additionally, the program must build, run and give correct output.

Extra Challenges (Not Required)

• Create additional operators.

Last Updated 09/11/2023