image file handling

[Pooja]

i want to know how to open an image file and dislay it through c file handling functions

[msaqib]

Hello
Here is a complete source code to open a bitmap image using C Language functions. I have compiled and run this program on Turbo C compiler.
source: http://www.brackeen.com/home/vga/bitmaps.html
Image:

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<br /> /*********************************************************** ***************<br /> * bitmap.c *<br /> * written by David Brackeen *<br /> * http://www.brackeen.com/home/vga/ *<br /> * This is a 16-bit program. *<br /> * Tab stops are set to 2. *<br /> * Remember to compile in the LARGE memory model! *<br /> * To compile in Borland C: bcc -ml bitmap.c *<br /> * This program will only work on DOS- or Windows-based systems with a *<br /> * VGA, SuperVGA or compatible video adapter. *<br /> * *<br /> * Please feel free to copy this source code. *<br /> * *<br /> * DESCRIPTION: This program demostrates drawing bitmaps, including *<br /> * transparent bitmaps. *<br /> ************************************************************ **************/<br /> #include <br /> #include <br /> #include <br /> #include <br /> #define VIDEO_INT 0x10 /* the BIOS video interrupt. */<br /> #define SET_MODE 0x00 /* BIOS func to set the video mode. */<br /> #define VGA_256_COLOR_MODE 0x13 /* use to set 256-color mode. */<br /> #define TEXT_MODE 0x03 /* use to set 80x25 text mode. */<br /> #define SCREEN_WIDTH 320 /* width in pixels of mode 0x13 */<br /> #define SCREEN_HEIGHT 200 /* height in pixels of mode 0x13 */<br /> #define NUM_COLORS 256 /* number of colors in mode 0x13 */<br /> typedef unsigned char byte;<br /> typedef unsigned short word;<br /> typedef unsigned long dword;<br /> byte *VGA=(byte *)0xA0000000L; /* this points to video memory. */<br /> word *my_clock=(word *)0x0000046C; /* this points to the 18.2hz system<br /> clock. */<br /> typedef struct tagBITMAP /* the structure for a bitmap. */<br /> {<br /> word width;<br /> word height;<br /> byte *data;<br /> } BITMAP;<br /> /*********************************************************** ***************<br /> * fskip *<br /> * Skips bytes in a file. *<br /> ************************************************************ **************/<br /> void fskip(FILE *fp, int num_bytes)<br /> {<br /> int i;<br /> for (i=0; i&lt;num_bytes; i++)<br /> fgetc(fp);<br /> }<br /> /*********************************************************** ***************<br /> * set_mode *<br /> * Sets the video mode. *<br /> ************************************************************ **************/<br /> void set_mode(byte mode)<br /> {<br /> union REGS regs;<br /> regs.h.ah = SET_MODE;<br /> regs.h.al = mode;<br /> int86(VIDEO_INT, &amp;regs, &amp;regs);<br /> }<br /> /*********************************************************** ***************<br /> * load_bmp *<br /> * Loads a bitmap file into memory. *<br /> ************************************************************ **************/<br /> void load_bmp(char *file,BITMAP *b)<br /> {<br /> FILE *fp;<br /> long index;<br /> word num_colors;<br /> int x;<br /> /* open the file */<br /> if ((fp = fopen(file,"rb")) == NULL)<br /> {<br /> printf("Error opening file %s.n",file);<br /> exit(1);<br /> }<br /> /* check to see if it is a valid bitmap file */<br /> if (fgetc(fp)!='B' || fgetc(fp)!='M')<br /> {<br /> fclose(fp);<br /> printf("%s is not a bitmap file.n",file);<br /> exit(1);<br /> }<br /> /* read in the width and height of the image, and the<br /> number of colors used; ignore the rest */<br /> fskip(fp,16);<br /> fread(&amp;b-&gt;width, sizeof(word), 1, fp);<br /> fskip(fp,2);<br /> fread(&amp;b-&gt;height,sizeof(word), 1, fp);<br /> fskip(fp,22);<br /> fread(&amp;num_colors,sizeof(word), 1, fp);<br /> fskip(fp,6);<br /> /* assume we are working with an 8-bit file */<br /> if (num_colors==0) num_colors=256;<br />  <br /> /* try to allocate memory */<br /> if ((b-&gt;data = (byte *) malloc((word)(b-&gt;width*b-&gt;height))) == NULL)<br /> {<br /> fclose(fp);<br /> printf("Error allocating memory for file %s.n",file);<br /> exit(1);<br /> }<br /> /* Ignore the palette information for now.<br /> See palette.c for code to read the palette info. */<br /> fskip(fp,num_colors*4);<br /> /* read the bitmap */<br /> for(index=(b-&gt;height-1)*b-&gt;width;index&gt;=0;index-=b- &gt;width)<br /> for(x=0;x<b>width;x++)<br /> b-&gt;data[(word)index+x]=(byte)fgetc(fp);<br /> fclose(fp);<br /> }<br /> /*********************************************************** ***************<br /> * draw_bitmap *<br /> * Draws a bitmap. *<br /> ************************************************************ **************/<br /> void draw_bitmap(BITMAP *bmp,int x,int y)<br /> {<br /> int j;<br /> word screen_offset = (y&lt;&lt;8)+(y&lt;&lt;6)+x;<br /> word bitmap_offset = 0;<br /> for(j=0;jheight;j++)<br /> {<br /> memcpy(&amp;VGA[screen_offset],&amp;bmp-&gt;data[bitmap_offset],bmp-&gt;width);<br /> bitmap_offset+=bmp-&gt;width;<br /> screen_offset+=SCREEN_WIDTH;<br /> }<br /> }<br /> /*********************************************************** ***************<br /> * draw_transparent_bitmap *<br /> * Draws a transparent bitmap. *<br /> ************************************************************ **************/<br /> void draw_transparent_bitmap(BITMAP *bmp,int x,int y)<br /> {<br /> int i,j;<br /> word screen_offset = (y&lt;&lt;8)+(y&lt;&lt;6);<br /> word bitmap_offset = 0;<br /> byte data;<br /> for(j=0;jheight;j++)<br /> {<br /> for(i=0;iwidth;i++,bitmap_offset++)<br /> {<br /> data = bmp-&gt;data[bitmap_offset];<br /> if (data) VGA[screen_offset+x+i] = data;<br /> }<br /> screen_offset+=SCREEN_WIDTH;<br /> }<br /> }<br /> /*********************************************************** ***************<br /> * wait *<br /> * Wait for a specified number of clock ticks (18hz). *<br /> ************************************************************ **************/<br /> void wait(int ticks)<br /> {<br /> word start;<br /> start=*my_clock;<br /> while (*my_clock-start&lt;ticks)<br /> {<br /> *my_clock=*my_clock; /* this line is for some compilers<br /> that would otherwise ignore this<br /> loop */<br /> }<br /> }<br /> /*********************************************************** ***************<br /> * Main *<br /> * Draws opaque and transparent bitmaps *<br /> ************************************************************ **************/<br /> void main()<br /> {<br /> int i,x,y;<br /> BITMAP bmp;<br /> load_bmp("rocket.bmp",&amp;bmp); /* open the file */<br /> set_mode(VGA_256_COLOR_MODE); /* set the video mode. */<br /> /* draw the background */<br /> for(i=0;i&lt;200;i++)<br /> memset(&amp;VGA[320*i],i,SCREEN_WIDTH);<br /> wait(25);<br /> /* draw a tiled bitmap pattern on the left */<br /> for(y=0;y&lt;=SCREEN_HEIGHT-bmp.height;y+=bmp.height)<br /> for(x=0;x&lt;=(SCREEN_WIDTH)/2-bmp.width;x+=bmp.width)<br /> draw_bitmap(&amp;bmp,x,y);<br /> wait(25);<br /> /* draw a tiled transparent bitmap pattern on the right */<br /> for(y=0;y&lt;=SCREEN_HEIGHT-bmp.height;y+=bmp.height)<br /> for(x=SCREEN_WIDTH-bmp.width;x&gt;=SCREEN_WIDTH/2;x-=bmp.wid th)<br /> draw_transparent_bitmap(&amp;bmp,x,y);<br /> wait(100);<br /> free(bmp.data); /* free up memory used */<br />  <br /> set_mode(TEXT_MODE); /* set the video mode back to<br /> text mode. */<br /> return;<br /> }<br /> </b>

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