(C++) SetPixelVcl

 

SetPixelVcl is a VCL graphics code snippet to set the color of a pixel.

 

---

#include <ExtCtrls.hpp> #include <cassert> //From http://www.richelbilderbeek.nl/CppSetPixelVcl.htm void SetPixelVcl(   TImage * const image,   const int x,   const int y,   const TColor color) {   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 line     = static_cast<unsigned char *>(image->Picture->Bitmap->ScanLine[y]);   line[x*3+2] = GetRValue(color);   line[x*3+1] = GetGValue(color);   line[x*3+0] = GetBValue(color); } #include <ExtCtrls.hpp> #include <cassert> //Set a pixel's RGB values //From http://www.richelbilderbeek.nl void SetPixelVcl(   TImage * const image,   const int x,   const int y,   const unsigned char red,   const unsigned char green,   const unsigned char blue) {   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 line     = static_cast<unsigned char *>(image->Picture->Bitmap->ScanLine[y]);   line[x*3+2] = red;   line[x*3+1] = green;   line[x*3+0] = blue; } //Set a line of pixels' RGB values //From http://www.richelbilderbeek.nl void SetPixelVcl(   TImage * const image,   const int x1,   const int x2,   const int y,   const unsigned char red,   const unsigned char green,   const unsigned char blue) {   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] = red;     myLine[x*3+1] = green;     myLine[x*3+0] = blue;   } } //Set a square of pixels' RGB values //From http://www.richelbilderbeek.nl void SetPixelVcl(   TImage * const image,   const int x1,   const int y1,   const int x2,   const int y2,   const unsigned char red,   const unsigned char green,   const unsigned char blue) {   for (int y=y1; y!=y2; ++y)   {     SetPixelVcl(image,x1,x2,y,red,green,blue);   } }