//From http://www.richelbilderbeek.nl/CppRotate.htm
void Rotate(
const TImage * const imageOriginal,
TImage * const imageResult,
const double angle)
{
const int maxx = imageResult->Picture->Bitmap->Width;
const int maxy = imageResult->Picture->Bitmap->Height;
const double midx = static_cast<double>(maxx) / 2.0;
const double midy = static_cast<double>(maxy) / 2.0;
for (int y=0; y!=maxy; ++y)
{
for(int x=0; x!=maxx; ++x)
{
const double dx1 = static_cast<double>(x) - midx;
const double dy1 = static_cast<double>(y) - midy;
double dx2, dy2; //Coordinats in original
Translate(dx1,dy1,angle,dx2,dy2);
const double x2 = (static_cast<double>(
imageOriginal->Picture->Bitmap->Width )
/ 2.0) + dx2;
const double y2 = (static_cast<double>(
imageOriginal->Picture->Bitmap->Height)
/ 2.0) + dy2;
if ( x2 < 1.0
|| y2 < 1.0
|| x2 >= imageOriginal->Picture->Bitmap->Width - 1.0
|| y2 >= imageOriginal->Picture->Bitmap->Height - 1.0
)
{ //Out of range
SetPixelVcl(imageResult,x,y,0,0,0);
continue;
}
unsigned char r,g,b;
GetPixel(imageOriginal,x2,y2,r,g,b);
SetPixelVcl(imageResult,x,y,r,g,b);
}
}
}
//---------------------------------------------------------------------------
//From http://www.richelbilderbeek.nl/CppRotate.htm
void GetPixel(
const TImage * const image,
const double x,
const double y,
unsigned char& red,
unsigned char& green,
unsigned char& blue)
{
const double xRemainder = x - static_cast<int>(x);
const double yRemainder = y - static_cast<int>(y);
const int x_tl = ( xRemainder > 0.5 ? x : x-1);
const int y_tl = ( yRemainder > 0.5 ? y : y-1);
const double left = ( xRemainder > 0.5
? 1.5 - xRemainder : 0.5 - xRemainder);
const double top = ( yRemainder > 0.5
? 1.5 - yRemainder : 0.5 - yRemainder);
return GetPixel(image,x_tl,y_tl,left,top,red,green,blue);
}
//---------------------------------------------------------------------------
//From http://www.richelbilderbeek.nl/CppRotate.htm
void GetPixel(
const TImage * const image,
const int x_tl,
const int y_tl,
const double left,
const double top,
unsigned char& red,
unsigned char& green,
unsigned char& blue)
{
const double right = 1.0 - left;
const double bottom = 1.0 - top;
assert(left >= 0.0 && left <=1.0);
assert(top >= 0.0 && top <=1.0);
assert(right >= 0.0 && right <=1.0);
assert(bottom >= 0.0 && bottom <=1.0);
unsigned char r_tl, g_tl, b_tl;
unsigned char r_tr, g_tr, b_tr;
unsigned char r_bl, g_bl, b_bl;
unsigned char r_br, g_br, b_br;
GetPixel(image,x_tl+0,y_tl+0,r_tl,g_tl,b_tl);
GetPixel(image,x_tl+1,y_tl+0,r_tr,g_tr,b_tr);
GetPixel(image,x_tl+0,y_tl+1,r_bl,g_bl,b_bl);
GetPixel(image,x_tl+1,y_tl+1,r_br,g_br,b_br);
const double rTotal
= (top * left * static_cast<double>(r_tl))
+ (top * right * static_cast<double>(r_tr))
+ (bottom * left * static_cast<double>(r_bl))
+ (bottom * right * static_cast<double>(r_br));
const double gTotal
= (top * left * static_cast<double>(g_tl))
+ (top * right * static_cast<double>(g_tr))
+ (bottom * left * static_cast<double>(g_bl))
+ (bottom * right * static_cast<double>(g_br));
const double bTotal
= (top * left * static_cast<double>(b_tl))
+ (top * right * static_cast<double>(b_tr))
+ (bottom * left * static_cast<double>(b_bl))
+ (bottom * right * static_cast<double>(b_br));
assert(rTotal >= 0.0 && rTotal < 256.0);
assert(gTotal >= 0.0 && gTotal < 256.0);
assert(bTotal >= 0.0 && bTotal < 256.0);
red = static_cast<unsigned char>(rTotal);
green = static_cast<unsigned char>(gTotal);
blue = static_cast<unsigned char>(bTotal);
}
//---------------------------------------------------------------------------
//From http://www.richelbilderbeek.nl/CppRotate.htm
void Translate(
const double dx1,
const double dy1,
const double dAngle,
double& dx2,
double& dy2)
{
const double oldAngle = GetAngle(dx1,dy1);
const double newAngle = oldAngle - dAngle;
const double ray
= std::sqrt((dx1 * dx1) + (dy1 * dy1)); //Pythagoras
dx2 = std::sin(newAngle) * ray;
dy2 = -std::cos(newAngle) * ray;
}
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