int main() {
int a, b, c;
int numerator, denominator;
numerator = 1;
denominator = 1;
for (a=1; a<=9; a++) {
for (b=1; b<=9; b++) {
for (c=1; c<=9; c++) {
if (a*(10*b+c) == c*(10*a+b) && a < c) {
printf("%d/%d is %d/%d\n", 10*a+b, 10*b+c, a, c);
numerator *= a;
denominator *= c;
}
}
}
}
printf("%d/%d is %d\n", numerator, denominator, maxDivisor(numerator, denominator));
printf("denominator is %d\n", denominator/maxDivisor(numerator, denominator));
return 0;
}
void SunLightBlending::blend( QImage * const tileImage, Tile const * const top ) const
{
if ( tileImage->depth() != 32 )
return;
// TODO add support for 8-bit maps?
// add sun shading
const TileId id = top->id();
const qreal global_width = tileImage->width()
* TileLoaderHelper::levelToColumn( m_levelZeroColumns, id.zoomLevel() );
const qreal global_height = tileImage->height()
* TileLoaderHelper::levelToRow( m_levelZeroRows, id.zoomLevel() );
const qreal lon_scale = 2*M_PI / global_width;
const qreal lat_scale = -M_PI / global_height;
const int tileHeight = tileImage->height();
const int tileWidth = tileImage->width();
// First we determine the supporting point interval for the interpolation.
const int n = maxDivisor( 30, tileWidth );
const int ipRight = n * (int)( tileWidth / n );
const QImage *nighttile = top->image();
for ( int cur_y = 0; cur_y < tileHeight; ++cur_y ) {
const qreal lat = lat_scale * ( id.y() * tileHeight + cur_y ) - 0.5*M_PI;
const qreal a = sin( ( lat+DEG2RAD * m_sunLocator->getLat() )/2.0 );
const qreal c = cos(lat)*cos( -DEG2RAD * m_sunLocator->getLat() );
QRgb* scanline = (QRgb*)tileImage->scanLine( cur_y );
const QRgb* nscanline = (QRgb*)nighttile->scanLine( cur_y );
qreal lastShade = -10.0;
int cur_x = 0;
while ( cur_x < tileWidth ) {
const bool interpolate = ( cur_x != 0 && cur_x < ipRight && cur_x + n < tileWidth );
qreal shade = 0;
if ( interpolate ) {
const int check = cur_x + n;
const qreal checklon = lon_scale * ( id.x() * tileWidth + check );
shade = m_sunLocator->shading( checklon, a, c );
// if the shading didn't change across the interpolation
// interval move on and don't change anything.
if ( shade == lastShade && shade == 1.0 ) {
scanline += n;
nscanline += n;
cur_x += n;
continue;
}
if ( shade == lastShade && shade == 0.0 ) {
for ( int t = 0; t < n; ++t ) {
m_sunLocator->shadePixelComposite( *scanline, *nscanline, shade );
++scanline;
++nscanline;
}
cur_x += n;
continue;
}
for ( int t = 0; t < n ; ++t ) {
qreal lon = lon_scale * ( id.x() * tileWidth + cur_x );
shade = m_sunLocator->shading( lon, a, c );
m_sunLocator->shadePixelComposite( *scanline, *nscanline, shade );
++scanline;
++nscanline;
++cur_x;
}
}
else {
// Make sure we don't exceed the image memory
if ( cur_x < tileWidth ) {
qreal lon = lon_scale * ( id.x() * tileWidth + cur_x );
shade = m_sunLocator->shading( lon, a, c );
m_sunLocator->shadePixelComposite( *scanline, *nscanline, shade );
++scanline;
++nscanline;
++cur_x;
}
}
lastShade = shade;
}
}
}