代做program、代写C/C++编程设计

日期：2024-09-13 10:02

PPM Image Transformations

Learning Objectives

Upon completion of this assignment, you should be able:

1. To develop, compile, run and test C programs in a Linux environment

2. To navigate Linux command lines reliably

The mechanisms you will practice using include:

Linux command lines: manual pages, Linux commands

C Programming: structs, pointers, memory allocation, getopt

Program Speciffcation

NAME

ppmcvt – convert ppm ffles

SYNOPSIS

ppmcvt [bg:i:r:smt:n:o:] ffle

DESCRIPTION

ppmcvt manipulates input Portable Pixel Map (PPM) ffles and outputs a new

image based on its given options. Only one option that speciffes a

transformation can be used at a time.

In the synopsis, options followed by a ‘:’ expect a subsequent parameter.

The options are:

-b

convert input ffle to a Portable Bitmap (PBM) ffle. (DEFAULT)

-g:

convert input ffle to a Portable Gray Map (PGM) ffle using the speciffed

max grayscale pixel value [1-65535].

-i:

isolate the speciffed RGB channel. Valid channels are “red”, “green”, or

“blue”.

-r:

remove the speciffed RGB channel. Valid channels are “red”, “green”,

or “blue”.

-s

apply a sepia transformation

-m

vertically mirror the ffrst half of the image to the second half

-t:

reduce the input image to a thumbnail based on the given scaling

factor [1-8].

-n: tile thumbnails of the input image based on the given scaling factor [1-

8].

-o:

write output image to the speciffed ffle. Existent output ffles will be

overwritten.

EXIT STATUS

ppmcvt exits 0 on success and 1 on failure.

EXAMPLES

ppmcvt -o out.pbm in.ppm

read in.ppm PPM ffle and write converted PBM ffle to out.pbm

ppmcvt -g 16 -o out.pgm in.ppm

convert the PPM image in.ppm to a PGM image in out.pgm

ppmcvt -s -o out.ppm in.ppm

apply a sepia transformation to the PPM image in in.ppm and output

the new image to out.ppm

ppmcvt -n 4 -o out.ppm in.ppm

tile 4 1:4-scaled (quarter-sized) thumbnails of the image in in.ppm into

a new PPPM image in out.ppm.

ERRORS

ppmcvt should print to the standard error output stream exactly the

speciffed line and then exit under the following circumstances:

"Usage: ppmcvt [-bgirsmtno] [FILE]\n": malformed command line

"Error: Invalid channel speciffcation: (%s); should be 'red', 'green' or 'blue'\

n”

"Error: Invalid max grayscale pixel value: %s; must be less than 65,536\n"

"Error: Invalid scale factor: %d; must be 1-8\n"

"Error: No input ffle speciffed\n"

"Error: No output ffle speciffed\n"

"Error: Multiple transformations speciffed\n"

(File errors are handled for you by the provided pbm library.)Implementation and Submission Details

You must implement ppmcvt according to the speciffcations given above. You

are given skeleton ffles, ppmcvt.c and pbm_aux.c, in which to place your

solution code. You may add helper functions to these ffles as you see fft.

You should do your testing from within you “priv” directory.

- Create an empty subdirectory, and copy pbm.c, pbm.h, and Makefile

from /home/cs350002/share/labs/lab0 to it.

- DO NOT ALTER those ffles

- copy Your ppmcvt.c and ppm_aux.c into that directory

- typing make should compile your ppmcvt for testing.

-you can test your ppmcvt against the reference ppmcvt provided.

There are some sample image ffles in the Image directory.

Start off with the small samples. You can also create your

own samples and even share with classmates.

When you are ready to submit create the lab0 subdirectory of cs350

(ie /home/YOURID/cs350/lab0) and copy ONLY your ppmcvt.c and pbm_aux.c

there.

The PBM Library (partially provided)

The given PBM library (pbm.h and pbm.c) does the following:

1. Deffnes structs for PBM, PGM and PPM image types;

2. Deffnes I/O routines to read/write the images from/to PBM, PGM and

PPM ffles.

a. (Note: The read routine does not handle image ffles with

embedded comments.)

3. Declares memory allocation/deallocation routines for PBM, PGM and

PPM structs.

a. You must implement these routines in pbm_aux.c.

Image File Formats

PPM, PGM and PBM ffles are simple (and inefffcient) ASCII text ffle image

formats comprising a small header followed by integer values that represent

each pixel in the image. Wikipedia has a good description here:

https://en.wikipedia.org/wiki/Netpbm.

Image Transformations

Your program should produce exactly the same output images as mine. My

program uses ffoating point arithmetic for all intermediate calculations then

converts the resulting ffoats to integers as appropriate.

Bitmap:

To compute black and white bits from RGB pixels use:Average( R+G+B)<PPMMax /2

Grayscale:

To compute grayscale pixels from RGB pixels use:

Average (R+G+B)

PPMMax

×PGMMax

Isolate:

For all pixels, set all but the speciffed “red”, “green” or “blue” channel to

0.

Remove:

For all pixels, set the speciffed “red”, “green” or “blue” channel to 0.

Sepia:

For the sepia transformation, compute RGB pixels as follows:

NewR=0.393 (OldR)+0.769 (OldG)+0.189 x (OldB)

NewG=0.349 (OldR)+0.686 (OldG)+0.168 x (OldB)

NewB=0.272 (OldR)+0.534 (OldG)+0.131 x (OldB)

Mirror:

Vertically reffect the left half of the image onto the right half.

Thumbnail:

The height and width of the output thumbnail should be 1/n the height and

width of the original image, respectively, where n is the input scale factor.

Shrink the input image simply by outputting every n

th

pixel in both

dimensions starting with the ffrst.

Nup:

Tile n 1/n scale thumbnails, where n is the input scale factor. The output

image should be the same size of the input image.

Requirements and Constraints

This assignment aims to make you familiar with some ‘C’ programming

basics. As such, we impose several requirements and constraints on your

implementation:

1. You may not modify pbm.h nor pbm.c: you will not submit these ffles.

We will compile your solutions using our original versions of these ffles.

2. You must use getopt() to process your program’s command line

inputs.

3. You must use the provided pbm library (described below)

4. You may use only the following library or helper functions:

a. C Memory Allocation: malloc(), realloc(), calloc(),

free()b. Command line parsing: getopt()

c. Other: fprintf(), strtol(), strcmp(), exit()

d. PBM library

5. Intermediate storage: You must use dynamically allocated memory to

store any intermediary image data. That is, you may not create

temporary image ffles nor use static arrays (for example, int

image[MAXHEIGHT][MAXWIDTH]). Instead, you should create an array

like: int **image and dynamically allocate the precise memory

needed depending on the image size.

6. You must free dynamically allocated memory immediately when no

longer needed.