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Graphics code snippet to draw a lymphocyte
* View an example image of an image created by 'DrawLymphocyte'.
* View the code of 'DrawLymphocyte' for VCL in plain text.
Under construction. Probably forever.
#include <cassert> //For assert
#include <cmath> //For std::sqrt
#include <algorithm> //For std::min
//From http://www.richelbilderbeek.nl/CppDrawLymphocyte.htm
void DrawLymphocyte(
TImage * const image,
const unsigned char rMax,
const unsigned char gMax,
const unsigned char bMax)
{
assert(image!=0);
const int width = image->Picture->Bitmap->Width;
const int height = image->Picture->Bitmap->Height;
const double midX = static_cast<double>(width ) / 2.0;
const double midY = static_cast<double>(height) / 2.0;
const double maxDist = std::min(midX,midY); //Distance to end
const double edgeDist = maxDist * 0.7; //Distance to edge
for (int y=0; y!=height; ++y)
{
unsigned char * const line
= static_cast<unsigned char *>(image->Picture->Bitmap->ScanLine[y]);
const double yD = static_cast<double>(y);
for (int x=0; x!=width; ++x)
{
const double xD = static_cast<double>(x);
const double dist = std::sqrt( ((xD - midX) * (xD - midX)) + ((yD - midY) * (yD - midY)) );
if (dist <= edgeDist)
{
const double relDist = dist / edgeDist;
const int r = (0.5 + (0.5 * relDist)) * static_cast<double>(rMax);
const int g = (0.5 + (0.5 * relDist)) * static_cast<double>(gMax);
const int b = (0.5 + (0.5 * relDist)) * static_cast<double>(bMax);
assert( r >= 0);
assert( r < 256);
assert( g >= 0);
assert( g < 256);
assert( b >= 0);
assert( b < 256);
line[x*3+2] = (r == 0 ? 1 : r); //Never use a zero for red
line[x*3+1] = (g == 0 ? 1 : g); //Never use a zero for green
line[x*3+0] = (b == 0 ? 1 : b); //Never use a zero for blue
}
else if (dist <= maxDist)
{
const double relDist = (dist - edgeDist) / (maxDist - edgeDist);
const int r = (0.5 + (0.5 * (1.0 - relDist))) * static_cast<double>(rMax);
const int g = (0.5 + (0.5 * (1.0 - relDist))) * static_cast<double>(gMax);
const int b = (0.5 + (0.5 * (1.0 - relDist))) * static_cast<double>(bMax);
assert( r >= 0);
assert( r < 256);
assert( g >= 0);
assert( g < 256);
assert( b >= 0);
assert( b < 256);
line[x*3+2] = (r == 0 ? 1 : r); //Never use a zero for red
line[x*3+1] = (g == 0 ? 1 : g); //Never use a zero for green
line[x*3+0] = (b == 0 ? 1 : b); //Never use a zero for blue
}
else
{
line[x*3+2] = 0;
line[x*3+1] = 0;
line[x*3+0] = 0;
}
}
}
}
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