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added alpha blending for image copying

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This commit is contained in:
Artem Pavlenko 2006-01-01 17:41:55 +00:00
parent b3330fc49b
commit 119c352fe7
3 changed files with 62 additions and 24 deletions
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63
include/graphics.hpp
View file

@ -44,8 +44,7 @@ namespace mapnik
~Image32();
static void setGamma(double gamma);
void setBackground(const Color& background);
const Color& getBackground() const;
void set_rectangle(unsigned x,unsigned y,const ImageData32& data);
const Color& getBackground() const;
const ImageData32& data() const;
inline ImageData32& data() {
return data_;
@ -92,7 +91,7 @@ namespace mapnik
int g=gammaTable_.l2g[(gammaTable_.g2l[green]*alpha+gammaTable_.g2l[bgGreen]*(255-alpha))>>8];
int b=gammaTable_.l2g[(gammaTable_.g2l[blue]*alpha+gammaTable_.g2l[bgBlue]*(255-alpha))>>8];
return 0xff<<24 | r<<16 | g<<8 | b;
return 0xff << 24 | r << 16 | g << 8 | b;
}
inline void blendPixel(int x,int y,unsigned int rgba,int t)
@ -114,6 +113,64 @@ namespace mapnik
{
return height_;
}
inline void Image32::set_rectangle(unsigned x0,unsigned y0,const ImageData32& data)
{
if (checkBounds(x0,y0))
{
unsigned w=std::min(data.width(),width_-x0);
unsigned h=std::min(data.height(),height_-y0);
for (unsigned y=0;y<h;++y)
{
for (unsigned x=0;x<w;++x)
{
if ((data(x,y) & 0xff000000))
{
data_(x0+x,y0+y)=data(x,y);
}
}
}
}
}
inline void set_rectangle_alpha(unsigned x0,unsigned y0,const ImageData32& data)
{
if (checkBounds(x0,y0))
{
unsigned w=std::min(data.width(),width_-x0);
unsigned h=std::min(data.height(),height_-y0);
for (unsigned y=0;y<h;++y)
{
for (unsigned x=0;x<w;++x)
{
unsigned rgba0 = data_(x0+x,y0+y);
unsigned rgba1 = data(x,y);
unsigned a1 = (rgba1 >> 24) & 0xff;
if (a1 == 0) continue;
unsigned r1 = rgba1 & 0xff;
unsigned g1 = (rgba1 >> 8 ) & 0xff;
unsigned b1 = (rgba1 >> 16) & 0xff;
unsigned a0 = (rgba0 >> 24) & 0xff;
unsigned r0 = (rgba0 & 0xff) * a0;
unsigned g0 = ((rgba0 >> 8 ) & 0xff) * a0;
unsigned b0 = ((rgba0 >> 16) & 0xff) * a0;
a0 = ((a1 + a0) << 8) - a0*a1;
r0 = ((((r1 << 8) - r0) * a1 + (r0 << 8)) / a0);
g0 = ((((g1 << 8) - g0) * a1 + (g0 << 8)) / a0);
b0 = ((((b1 << 8) - b0) * a1 + (b0 << 8)) / a0);
a0 = a0 >> 8;
data_(x0+x,y0+y)= (a0 << 24)| (b0 << 16) | (g0 << 8) | (r0) ;
}
}
}
}
};
}
#endif //GRAPHICS_HPP

2
include/image_symbolizer.hpp
View file

@ -63,7 +63,7 @@ namespace mapnik
geom.vertex(&x,&y);
int px=int(x - 0.5 * w);
int py=int(y - 0.5 * h);
image.set_rectangle(px,py,symbol_);
image.set_rectangle_alpha(px,py,symbol_);
}
}
};

21
src/graphics.cpp
View file

@ -56,26 +56,7 @@ namespace mapnik
{
return background_;
}
void Image32::set_rectangle(unsigned x0,unsigned y0,const ImageData32& data)
{
if (x0>=width_ || y0>=height_) return;
unsigned w=std::min(data.width(),width_-x0);
unsigned h=std::min(data.height(),height_-y0);
for (unsigned y=0;y<h;++y)
{
for (unsigned x=0;x<w;++x)
{
if ((data(x,y) & 0xff000000))
{
data_(x0+x,y0+y)=data(x,y);
}
}
}
}
void Image32::saveToFile(const std::string& file,const std::string& format)
{
//TODO: image writer factory