Screenshots to write data

I have written in c + + stand out figure size of 1 * 1 pixel display normal 24 true-color output

But I use a hexadecimal view file data right

Should be after 54 byte + 4 bytes of data (3 bytes color and 1 byte alignment)

Hexadecimal view there are 7 bytes???

Sometimes is right 4 bytes

CodePudding user response:

Capture the image of key code

 


//interception picture 
Bool pixelex: : captrue (long long x, long y, long w, h, char * filepath) 
{
//path processing 
//setpath (filepath); 
Filepath="c:/123. TXT". 
Long pixelLength; 
Byte * pixelDate=NULL; 
The FILE * wfile=NULL; 
//open the file 
Wfile=fopen (filepath, "wb"); 
Fwrite (head, 54, 1, wfile); 
//change the grab. BMP height and width of the header file 
Fseek (wfile, 0 x0012, SEEK_SET); 
Fwrite (& amp; W, sizeof (w), 1, wfile); 
Fwrite (& amp; H, sizeof (h), 1, wfile); 
//allocate memory for pixel 
PixelLength=w * 3; 
If (pixelLength % 4!=0) 
{
4 - pixelLength pixelLength +=% 4; 
} 
PixelLength *=h; 
PixelDate=(byte *) malloc (pixelLength); 
If (pixelDate==0) 
{
AfxMessageBox (L "memory allocation failure"); 
} 

If (ishaverc) 
{
GlReadPixels (x, y, w, h, GL_BGR_EXT, GL_UNSIGNED_BYTE, pixelDate); 
glFlush(); 
//AfxMessageBox (L "has"); 
} the else 
{
Bool ok=apihook: : getdx () - & gt; Readpix (x, y, w, h, pixelDate); 
if(! Ok) 
{
The fclose (wfile); 
Free (pixelDate); 
return false; 
} 
//AfxMessageBox (L "no"); 
} 


Cstrings o; 
O.F ormat (L "% d", pixelLength); 
AfxMessageBox (o); 
There is nothing wrong with//output has been here 4 

Fseek (wfile, 0, SEEK_END); 
Fwrite (pixelDate pixelLength, 1, wfile); 
The fclose (wfile); 
Free (pixelDate); 
return true; 
} 

CodePudding user response:

Key point is not BMP should be 4 byte aligned but 7 bytes. It is normal yellow,,,,,,,,