Zoom

This is a discussion on Zoom within the C Programming forums, part of the General Programming Boards category; Trying to complete these requirements for the following code. Im stuck and would greatly appreciate any assistance. Your program shall ...

  1. #1
    Registered User
    Join Date
    Apr 2009
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    2

    Unhappy Zoom

    Trying to complete these requirements for the following code.
    Im stuck and would greatly appreciate any assistance.


    Your program shall use dynamic memory allocation to handle icons of an arbitrary
    size with only one restriction that icon width must be a multiple of 8. The allocated
    memory size to store icon data shall be the icon size dependent. When an icon is to
    be zoomed in, the memory block must be reallocated. All dynamic memory
    operations must not produce memory leaks.
    Zoom in by 2 can be implemented by repeating each pixel element twice. Zoom
    operation must be applicable to the icon rows and the icon columns.
    To draw an icon, the user shall use * and space characters. Different methods may
    be used to convert a sequence of these characters entered by the user into an
    unpacked sequence of 0 and 1. For example, a line of characters may be read into a
    character array buffer when Enter key is pressed using gets function. After that,
    the program can read the buffered characters sequentially checking their ASCII
    codes. If characters other than * and space are found in the buffer, or a number of
    characters does not match the icon width, the program must prompt the user to
    repeat entering the line.
    CODING REQUIREMENTS
    Your program shall be menu driven and the menu options shall be context
    dependent.
    ----Menu----
    1 Open an Icon
    2 New Icon
    2 Exit the program
    Please select an option (1 - 3):
    If the first option is selected, your program shall prompt the user to enter the file
    name and open the specified file. Your program shall support only file formats with
    U or P identifiers. If other identifiers are detected, the program shall display a
    message:
    Unsupported file format
    and return to the previous menu.
    If the format is supported, the program shall display the header information as
    shown in the example below:
    File format: Unpacked
    Icon width: 8 pixels
    Icon height: 4 pixels
    and display the icon using space and * symbols, as shown below:
    *******
    * *
    * *
    *******
    After that, if the displayed icon is in the unpacked format, the program shall display
    the second menu:
    ----Menu----
    1 Save an Icon in the Packed Format
    2 Zoom In x2
    3 Exit the program
    Please select an option (1 - 3):
    Otherwise, the first menu shall be displayed.
    ----Menu----
    1 Open an Icon
    2 New Icon
    2 Exit the program
    Please select an option (1 - 3):
    If the second option is selected, your program shall prompt the user to enter the icon
    width and height. The icon width must be a multiple of 8. Then, the program
    shall prompt the user to draw the icon line-by-line typing * and space characters.
    When the drawing process is complete, the second menu shall be displayed.
    ----Menu----
    1 Save an Icon in the Packed Format
    2 Zoom In x2
    3 Exit the program
    Please select an option (1 - 3):
    If the second option is selected, your program shall display new width and height,
    and then display the icon using space and * symbols, as shown below:
    **************
    **************
    ** **
    ** **
    ** **
    ** **
    **************
    **************
    ----Menu----
    1 Save an Icon in the Packed Format
    2 Zoom In x2
    3 Exit the program
    Please select an option (1 - 3):
    The magnified icon can be saved in the packed format with a specified file name if
    option 1 is selected. If the option 3 is selected the icon data are discarded and the
    program is terminated.

    Code:
    #include <stdio.h>
    #include <stdbool.h>
    
    #define MAXSIZE  512			/* the size limit for icons */
    #define	CHARNUM	 8				/* number of bits in a byte */
    #define MASKPACK 1				/* mask for packing of data */
    #define MASKUN   128			/* mask for unpacking of data */
    
    /* header structure definition */
    /* the header size should be 3 bytes to match the file format */
    #pragma pack(push, 1)
    typedef struct
    {
        char format;                   /* 'U' - unpacked format, 'P' - packed format */
    	unsigned char width;           /*  icon width and  icon height */
    	unsigned char height;
    }header;                           
    #pragma pop
    
    /* - function prototypes - */
    int displayMenu(int version);
    void clearStdin(void);
    header openIcon( unsigned char pixelData[] );
    void displayIcon( unsigned char pixelData[], header iconParam );
    bool saveIconPacked( unsigned char pixelData[], header iconParam );
    void packIconData( unsigned char pixelData[],  header iconParam );
    void unpackIcon( unsigned char pixelData[], header iconParam );
    
    
    int main(void)
    {
       int menuOption;	                  /* suppose to be 1 or 2, if entered by a user correctly*/
       int menuVersion=1;                 /* 1 - the first menu, 2 - the second menu, 1 or 2 is context dependent */
       header icParam;	                  
       unsigned char pixelData[MAXSIZE];  /* icon pixel data from a file*/
       
       do
       {
          menuOption = displayMenu(menuVersion);          /* display menu an get the option entered */
    	  
    	  if((menuOption != 1) && (menuOption != 2) && (menuOption != 3)
    	  {                                           /* only menu options 1 and 2 and 3 are valid */
    	    fprintf(stderr, "\nIncorrect option!\n");
    	  }
    	  else if(menuOption==1)
    	  {
    		      if(menuVersion==1)  /* if menu version is 1 - open an icon */
    		      {
    			     icParam = openIcon( pixelData );
    			     if( icParam.format == -1 )
    				 {
    				    fprintf(stderr, "\nThe icon cannot be opened!\n");
    					return -1;
    				 }
    	 
    				 if(icParam.format=='U') 
    				 {
    				 	
    					menuVersion = 2;
    					
    				 }
    				 
    		      }
    		      else if(menuVersion==2);  /* if menu version is 2 - save the icon */
                          {
    			              if( saveIconPacked( pixelData, icParam ) == false )
    		                  {
    			                  fprintf(stderr, "The icon cannot be saved!\n");
    			                  return -1;
    		                  }
                              
    						  fprintf(stderr,  "The icon has been packed and saved\n");
    			              menuVersion = 1;          /* change the menu to menu 1*/
                          }
    	   }     
       }while( menuOption != 3 );          /* repeat while option 2 is not selected */
       	{
       		printf("Bye-bye!\n");
    	}
       return 0;
    }
    
    /*- function definitions -*/
    
    /* printf("displayMenu is called and printed") */
    int displayMenu(int Version)
    {
       int option=0;
       
       printf("\n----Menu----\n");
       if(Version == 1)
       
          printf("1 Open an Icon\n");
    	  printf("2 New Icon\n");
    	  printf("3 Exit the Program\n");
    	  printf("Please select an option (1 -3): ");
         
       else
       printf("1 Save an Icon in the Packed Format\n");
       printf("2 Zoom In x2\n");
       printf("3 Exit the program\n");
       printf("Please select an option (1 - 3): ");
       
       if(scanf("%d", &option) !=1)   /* input failure? */
       	clearStdin();	          /* remove wrong characters from stdin */
       
       return option;
    }
    /*printf("clearStdin is called and performed") */
    void clearStdin(void)  /* remove wrong characters from stdin */
    {
       scanf("%*[^\n]");   /* skip to the end-of-line */
       scanf("%*1[\n]");   /* skip one new-line */
       return;    
    }
    /*printf("openIcon is passed through the header file and performed")*/
    header openIcon( unsigned char data[] )
    {
        char iconFormat;           /* 'U' - unpacked format, 'P' - packed format */
    	char fileName[20];
    	FILE *iconF;
    	header fileHeader;  /* width, height and number of values of an icon */
    	int values;
       
        printf("\nEnter the file name:");
    	scanf("%s", fileName);
    	
        iconF = fopen(fileName, "rb" );  /* open a file stream for reading, the binary mode */ 
        if( iconF == NULL )    
        {
    	    fileHeader.format = -1;  /* return -1, if the icon cannot be opened */
    		return fileHeader;
        }   
    
    	/* read the header */
        if( fread( &fileHeader, sizeof(header), 1, iconF ) != 1 )
        {
    	    fileHeader.format = -1;  /* return -1, file read error */
    		return fileHeader;
        }
    
    	 values = fileHeader.width * fileHeader.height;
         /* check if the icon size is not above the limit */
        if( values>512 ) 
        {
    	    fileHeader.format = -1;  /* return -1, the icon is to big to be opened */
    		return fileHeader;
        }    
    	
        if(iconFormat == 'P')   /* packed data require 8 times less values */
          values /= 8;
         
        if( fread( data, sizeof(unsigned char), values, iconF ) != values )  /* read the pixel values */
        {
    	    fileHeader.format = -1;  /* return -1, error */
    		return fileHeader;
        } 
    	
        fclose( iconF );
    	
        displayIcon( data, fileHeader );
       
        return fileHeader;
    }
    
    
    void displayIcon( unsigned char data[], header iconPar )
    {
       int column, row;
       
       /* display the header info */
       if(iconPar.format == 'U')
          printf("File format: Unpacked\n"  );
       else
       {
          printf("File format: Packed\n");
    	  unpackIcon( data, iconPar );   /* unpack pixels before displaying */
       }
       printf("Icon width: %d pixels\n", iconPar.width);
       printf("Icon height: %d pixels\n", iconPar.height);
       
       /* display the icon */
       for(row=0; row<iconPar.height; row++)
       {
          printf("\n");
    	  for(column=0; column<iconPar.width; column++)
    	  {
    	    if(data[iconPar.width*row + column] == 1) printf("*");
    	    else printf(" ");
    	  }	     	
       }
          	   
       printf("\n");
       	    
       return;
    }
    
    /* the function takes the icon data from pixelData array 
       unpack them and places back into the pixelData array */
    void unpackIcon( unsigned char pixelData[],  header iconParam )
    {
    	int a, b, c=0;
    	unsigned char unp[MAXSIZE];
    	
    	for(a=0; a<=(iconParam.height*iconParam.width/CHARNUM); a++)
    	{									/* allocates the pixel values with one bit per pixel value */
    		for(b=1; b<=CHARNUM; b++)
    		{
    			if((pixelData[a] & MASKUN)>0)
    			{
    				unp[c] = 1;
    			}
    			else unp[c] = 0;
    		
    		pixelData[a]<<=1;
    		
    		c++;
    		}
    	}
    	for(a=0; a<=MAXSIZE; a++)
    	{
    	pixelData[a] = unp[a];
    	}
    	
      return;	
    
    }
    
    
    
    /* the function takes the icon data from pixelData array 
       pack them and places back into the pixelData array */
    void packIconData( unsigned char pixelData[],  header iconParam )
    {
    	int a, b, c=0;
    	unsigned char packb;
    	
    	for(a=0; a<(iconParam.height*iconParam.width/CHARNUM); a++)
    	{
    		packb = 0;						/* resets packbyte(packb) to 0 */
    		for(b=0; b<CHARNUM; b++)				
    		{
    			if(pixelData[b] == MASKPACK)
    			{
    				packb = packb | MASKPACK;
    			}						/* shifts packbyte(packb) left 1 place after equalling 1 */
    			if(b<(CHARNUM-1))
    			{
    				packb<<=1;
    			}
    			c++;
    		}
    		pixelData[a]=packb;
    	}
    				
        return;
    
    }
    
    
    
    /* the function takes two parameters:
          -an array filled with unpacked pixel data
    	  -the iconParam - format, width , height
       calls packIconData() function
       saves packed icon in a binary file 
       returns true if OK, otherwise false   */ 
    bool saveIconPacked( unsigned char pixelData[], header iconParam )
    {
      FILE *Save;
      char filename;
      unsigned char bytes = (iconParam.height*iconParam.width/CHARNUM);
      
      printf("Enter the file name:");
      scanf("%s", &filename);
      
      iconParam.format = 'P';								/* the data has become packed */
      
      packIconData(pixelData, iconParam);
      
      Save = fopen(filename, "wb");
      
      if(Save == NULL)
      {
    	fprintf(stderr, "Could not find file!\n");	 	 	 	 	 	 /* error recovery for saving of file */
      	return false;
      }
      	else if(fwrite(&iconParam, sizeof(header), 1, Save)!=1)				/* saves header to the new file */
      	{
      		return false;
      	}
      		else if(fwrite(pixelData, sizeof(unsigned char), bytes, Save)!=bytes)	    		/* saves pixel data to the new file */
      		{
      			return false;
      		}
      		else
       	 		fclose(Save);									/* closes file and returns to the start */
        		 return true;
    	
    	
    }

  2. #2
    Registered User
    Join Date
    Sep 2006
    Posts
    8,868
    JMA619, saying "I'm stuck" doesn't really say much to help us zoom in (pardon the pun), on your code's problem.

    WHAT *specifically* is the problem that you're seeing? What have you tried to fix it?

    You can't just post your assignment requirements and a bunch of code, and say "I'm stuck"!

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