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Bitmap/Flood fill: Difference between revisions
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=={{header|C}}==
===A simple and complete example in C89===
<lang C>/*
* RosettaCode: Bitmap/Flood fill, language C, dialects C89, C99, C11.
*
* This is an implementation of the recursive algorithm. For the sake of
* simplicity, instead of reading files in JPEG, PNG, etc., the program
* read and write Portable Bit Map (PBM) files in plain text format.
* Portable Bit Map files can also be read and written with GNU GIMP.
*
* The program is just an example, so the image size is limited to 2048x2048,
* the image can only be black and white, there is no run-time validation.
*
* Data is read from a standard input stream, the results are written to the
* standard output file.
*
* Note: In order for a program to work properly it is necessary to allocate
* enough memory for the program stack. For example, in Microsoft Visual Studio,
* the / stack option: 134217728 declares a 128MB stack instead of the default
* size of 1MB.
*/
#define _CRT_SECURE_NO_WARNINGS /* Unlock printf etc. in MSVC */
#include <stdio.h>
#include <stdlib.h>
#define MAXSIZE 2048
#define BYTE unsigned char
static int width, height;
static BYTE bitmap[MAXSIZE][MAXSIZE];
static BYTE oldColor;
static BYTE newColor;
static void skipLine(FILE* file)
{
int c;
while(!ferror(file) && !feof(file) && (c = fgetc(file)) != '\n')
;
}
static void skipCommentLines(FILE* file)
{
int c;
int comment = '#';
while ((c = fgetc(file)) == comment)
skipLine(file);
ungetc(c,file);
}
void readPortableBitMap(FILE* file)
{
int i,j;
skipLine(file);
skipCommentLines(file); fscanf(file,"%d",&width);
skipCommentLines(file); fscanf(file,"%d",&height);
skipCommentLines(file);
if ( width <= MAXSIZE && height <= MAXSIZE )
for ( i = 0; i < height; i++ )
for ( j = 0; j < width; j++ )
fscanf(file,"%1d",&(bitmap[i][j]));
else exit(EXIT_FAILURE);
}
void writePortableBitMap(FILE* file)
{
int i,j;
fprintf(file,"P1\n");
fprintf(file,"%d %d\n", width, height);
for ( i = 0; i < height; i++ )
{
for ( j = 0; j < width; j++ )
fprintf(file,"%1d", bitmap[i][j]);
fprintf(file,"\n");
}
}
static void floodFill(int i, int j)
{
if ( 0 <= i && i < height
&& 0 <= j && j < width
&& bitmap[i][j] == oldColor )
{
bitmap[i][j] = newColor;
floodFill(i-1,j);
floodFill(i+1,j);
floodFill(i,j-1);
floodFill(i,j+1);
}
}
int main(void)
{
oldColor = 1;
newColor = oldColor ? 0 : 1;
readPortableBitMap(stdin);
floodFill(height/2,width/2);
writePortableBitMap(stdout);
return EXIT_SUCCESS;
}</lang>
===First example ===
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