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SetGreyness

The greyness of a pixels is the averaged red, green and blue value of it. You can set a single pixel's greyness, a horizontal line or a square of pixels.

To get pixels' their greynesses, use the GetGreyness function.

* View the code of 'SetGreyness' in plain text.

//Set a pixel's greyness

//From http://www.richelbilderbeek.nl

void SetGreyness(

TImage * const image,

const int x,

const int y,

const unsigned char grey)

{

assert(image!=0 && "Image is NULL");

assert(image->Picture->Bitmap!=0 && "Bitmap is NULL");

assert(image->Picture->Bitmap->PixelFormat == pf24bit && "Bitmap must be 24 bit");

assert( x >= 0 && "x coordinat is below zero");

assert( y >= 0 && "y coordinat is below zero");

assert( x < image->Picture->Bitmap->Width && "x coordinat is beyond image width");

assert( y < image->Picture->Bitmap->Height && "y coordinat is beyond image height");

unsigned char * const myLine

= static_cast<unsigned char *>(image->Picture->Bitmap->ScanLine[y]);

myLine[x*3+2] = grey;

myLine[x*3+1] = grey;

myLine[x*3+0] = grey;

}

//Set a line of pixel's greyness

//From http://www.richelbilderbeek.nl

void SetGreyness(

TImage * const image,

const int x1,

const int x2,

const int y,

const unsigned char grey)

{

assert(image!=0 && "Image is NULL");

assert(image->Picture->Bitmap!=0 && "Bitmap is NULL");

assert(image->Picture->Bitmap->PixelFormat == pf24bit && "Bitmap must be 24 bit");

assert( x1 >= 0 && "x1 coordinat is below zero");

assert( x2 >= 0 && "x2 coordinat is below zero");

assert( y >= 0 && "y coordinat is below zero");

assert( x1 < image->Picture->Bitmap->Width && "x1 coordinat is beyond image width");

assert( x2 <= image->Picture->Bitmap->Width && "x2 coordinat is beyond image width");

assert( y < image->Picture->Bitmap->Height && "y coordinat is beyond image height");

unsigned char * const myLine

= static_cast<unsigned char *>(image->Picture->Bitmap->ScanLine[y]);

for (int x=x1; x!=x2; ++x)

{

myLine[x*3+2] = grey;

myLine[x*3+1] = grey;

myLine[x*3+0] = grey;

}

}

//Set a square of pixels' greyness

//From http://www.richelbilderbeek.nl

void SetGreyness(

TImage * const image,

const int x1,

const int y1,

const int x2,

const int y2,

const unsigned char grey)

{

for (int y=y1; y!=y2; ++y)

{

SetGreyness(image,x1,x2,y,grey);

}

}

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