Question

This is your last assignment for this course! It is about 3D vectors and arrays. You can either choose to work with vectors or arrays. You don't need to do both (but, you can!). I am going to describe it using the word array. You can translate it for vectors. The dimensions of the array are 200x600x3. The datatype of the values stored in the array are unsigned char (ranges from 0 to 255). The first dimension 200 is the number of rows. The second dimension 600 is the number of columns and the third dimension represents three colors. Index O in the 3rd dimension is red, index 1 is green and index 2 is blue. Actually, the array represents an image of size 200 pixels by 600 pixels. Divide the image into 3 regions of 200x200 pixels each. For each region assign a different background color. In each region create one letter using rectangles as shown in the attached image. Color the rectangles as you wish. You don't need to color the borders differently. Then write the output according to the ppm format described in the reference below. If you want more challenge then use the P6 format. Make sure you use functions. Write each function to accomplish a single task. CSC 101 HW 10.png

Using C++ Language

Answer 1

Summary :

Following are provided as part of the solution (i) notes , (ii) code & output

Notes :

Utilizing the array of pixels for 3 dimension , store the pixel data and following functions are implemented to achive the task.

fillPixels() - this method fills the rectangle area of 200x600 by white pixels

writePixels() this method takes the pixesl array and filename and writes the pixesl to file in ppm format.

drawRectangle() this method draws a rectangle of given width and height and given center x,y , in the pixel array and given rbg color.

drawL() this tries to draw a L shape given x1 , x2 and of width w and given color .

Utilizing above functions drew the given pattern as follow:

Divide the 200x600 into 3 compartments and in each comparment divide the height into 8 ( 25x8) and for eg S is achieved by drawing slabs of 3 horizontal bars and emebedded with square blocks of 25x25 each on either side .

############################### Code ###################

#include <iostream>
#include <fstream>

using namespace std;

#define HEIGHT 200
#define WIDTH 600
#define RGBNUM 3

// Draws a rectangle of given height , wdith and center x,y and with colors rgb
void drawRectangle(int pixel[HEIGHT][WIDTH][RGBNUM] , int x, int y , int ht , int wd , int cr , int cg , int cb)
{

        if ( (( y - ht/2 ) >= 0 ) & ( ( y + ht/2 ) <= HEIGHT ) & ( ( x - wd/2) >= 0  ) & ( (x + wd/2 ) <= WIDTH)) 
        {
                        
                for (int r = (y-ht/2) ; r <= ( y+ht/2 ) ; r++ )
                {
                        for (int c = (x-wd/2) ; c <= ( x+wd/2 ) ; c++ )
                        {
                                pixel[r][c][0] = cr ;
                                pixel[r][c][1] = cg ;
                                pixel[r][c][2] = cb ;
                        }
                }
                
        }
        else {
                cout << "  Rectangle  Out of range " <<  x << "  " << y << "\n";
        }
}

// fills the rectangle area with whilte pxels
void fillPixels ( int pixel[HEIGHT][WIDTH][RGBNUM] )
{
        for( int i=0 ; i < HEIGHT ; i++ )
        {
                for (int j=0 ; j< WIDTH ; j++ )
                {
                        pixel[i][j][0] = 255 ;
                        pixel[i][j][1] = 255 ;
                        pixel[i][j][2] = 255 ;
                }
        }
}

// Draws a L shape at given x1 to x2 of width and fill it with rgb 
void drawL(int pixel[HEIGHT][WIDTH][RGBNUM] , int x1, int x2, int y ,  int width , int height, int r , int g , int b)
{
        
        for( int i=0 ; i < width ; i++ )
        {
                int y1 = y ;
                for( int j = 0 ;  j < i+(x2-x1)/2  ; j++ )
                {
                        //cout << " X1 + j " << (x1 +  j )  << " x2 - j " << (x2- j ) << "\n";
                        pixel[y1][x1 + j - i][0] = r ; pixel[y1][x1+ j -i ][1] = g ; pixel[y1][x1+j-i][2] = b;
                        pixel[y1][x2 - j +i  ][0] = r ; pixel[y1][x2- j +i][1] = g ; pixel[y1][x2-j +i][2] = b;
                        
                        if ( (x1 + j - i ) == (x2 - j +i) ) 
                                break;
                        y1++;
                }
        }
}

void writeToFile(int pixel[HEIGHT][WIDTH][RGBNUM] , string filename )
{
        
         ofstream fhOut(filename);
          if (!fhOut.is_open()) {
                cout << "Cannot open output file : " <<   filename << "\n";
                return ;
        }
          
          fhOut << "P3\n"; 
          fhOut << WIDTH << " " <<  HEIGHT<< "\n";
          fhOut << 255 << "\n";
         
          for( int i=0 ; i < HEIGHT ; i++ )
        {
                for (int j=0 ; j< WIDTH ; j++ )
                {
                        fhOut << pixel[i][j][0] << " "
                                 << pixel[i][j][1]  << " "
                        << pixel[i][j][2]  << "  ";
                }
                fhOut << "\n";
        }
          
        fhOut.close();
}

int main()
{
        int ppm_pixels[200][600][3] ;
        
        fillPixels(ppm_pixels);
        // Vertical Bar Right
        //drawRectangle(ppm_pixels,150,100 , 20,30,34,35,150);
        
        //drawRectangle(ppm_pixels,75,75 , 100,15,30,50,150);
        // Vertical Bar left 
        //drawRectangle(ppm_pixels,175,75 , 100,15,30,50,150);
        
        // Base block 
        drawRectangle(ppm_pixels,100,138 , 25,100,30,50,150);
        
        drawRectangle(ppm_pixels,62.5,75 , 100 ,25,30,50,150);
        drawRectangle(ppm_pixels,138,75 , 100 ,25,30,50,150);
        
        //drawRectangle(ppm_pixels,300,150 , 25,100,30,50,150);
        
        // Draw middle S 
        drawRectangle(ppm_pixels,300,38 , 25,100,100,50,150);
        drawRectangle(ppm_pixels,262.5,63 , 25,25,100,50,150);
        
        drawRectangle(ppm_pixels,300,86 , 25,100,100,50,150);
        drawRectangle(ppm_pixels,338,111 , 25,25,100,50,150);

        drawRectangle(ppm_pixels,300,136 , 25,100,100,50,150);
        
        //drawRectangle(ppm_pixels,500,150 , 15,100,30,50,150);
        
        // Draw M 
        // vertical bars 2
        drawRectangle(ppm_pixels,450,85 , 125 ,25,30,150,150);
        drawRectangle(ppm_pixels,550,85 , 125 ,25,30,150,150);
        drawL(ppm_pixels,462.5,537.5,25, 25,575,30,150,150);
        writeToFile(ppm_pixels,"rct.ppm");
        
}

######################## Output #####################

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