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add missing set_color_to_alpha impl - TODO - add advanced algo that supports tolerance - refs #1018

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This commit is contained in:
Dane Springmeyer 2012-04-03 16:49:05 -07:00
parent c88fcc8f04
commit 40e8ceca55
1 changed files with 17 additions and 2 deletions
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19
src/graphics.cpp
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@ -25,6 +25,7 @@
#include <mapnik/graphics.hpp>
#include <mapnik/image_util.hpp>
#include <mapnik/global.hpp>
#include <mapnik/color.hpp>
// cairo
#ifdef HAVE_CAIRO
@ -117,9 +118,23 @@ void image_32::set_grayscale_to_alpha()
}
}
void image_32::set_color_to_alpha(const color& /*c*/)
void image_32::set_color_to_alpha(const color& c)
{
// TODO - function to set all pixels to a % alpha based on distance to a given color
for (unsigned y = 0; y < height_; ++y)
{
unsigned int* row_from = data_.getRow(y);
for (unsigned x = 0; x < width_; ++x)
{
unsigned rgba = row_from[x];
unsigned r = rgba & 0xff;
unsigned g = (rgba >> 8 ) & 0xff;
unsigned b = (rgba >> 16) & 0xff;
if (r == c.red() && g == c.green() && b == c.blue())
{
row_from[x] = 0;
}
}
}
}
void image_32::set_alpha(float opacity)