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qt3/examples/canvas/makeimg.cpp

93 lines
2.1 KiB

#include <qimage.h>
#include <qcolor.h>
static inline int blendComponent( int v, int av, int s, int as )
{
//shadow gets a color inversely proportional to the
//alpha value
s = (s*(255-as))/255;
//then do standard blending
return as*s + av*v -(av*as*s)/255;
}
static inline QRgb blendShade( QRgb v, QRgb s )
{
//pick a number: shadow is 1/3 of object
int as = qAlpha(s)/3;
int av = qAlpha(v);
if ( as == 0 || av == 255 )
return v;
int a = as + av -(as*av)/255;
int r = blendComponent( qRed(v),av, qRed(s), as)/a;
int g = blendComponent( qGreen(v),av, qGreen(s), as)/a;
int b = blendComponent( qBlue(v),av, qBlue(s), as)/a;
return qRgba(r,g,b,a);
}
int main( int*, char**)
{
QImage *img;
img = new QImage( "in.png" );
int w,h;
int y;
img->setAlphaBuffer( TRUE );
*img = img->convertDepth( 32 );
w = img->width();
h = img->height();
#if 0
for ( y = 0; y < h; y ++ ) {
uint *line = (uint*)img->scanLine( y );
for ( int x = 0; x < w; x++ ) {
uint pixel = line[x];
int r = qRed(pixel);
int g = qGreen(pixel);
int b = qBlue(pixel);
int min = QMIN( r, QMIN( g, b ) );
int max = QMAX( r, QMAX( g, b ) );
r -= min;
g -= min;
b -= min;
if ( max !=min ) {
r = (r*255)/(max-min);
g = (g*255)/(max-min);
b = (b*255)/(max-min);
}
int a = 255-min;
a -= (max-min)/3; //hack more transparency for colors.
line[x] = qRgba( r, g, b, a );
}
}
#endif
*img = img->smoothScale( w/2, h/2 );
qDebug( "saving out.png");
img->save( "out.png", "PNG" );
w = img->width();
h = img->height();
QImage *img2 = new QImage( w, h, 32 );
img2->setAlphaBuffer( TRUE );
for ( y = 0; y < h; y++ ) {
for ( int x = 0; x < w; x++ ) {
QRgb shader = img->pixel( x, y );
int as = qAlpha(shader)/3;
int r = (qRed(shader)*(255-as))/255;
int g = (qGreen(shader)*(255-as))/255;
int b = (qBlue(shader)*(255-as))/255;
img2->setPixel( x, y, qRgba(r,g,b,as) );
}
}
img2->save( "outshade.png", "PNG" );
}