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/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2011 Artem Pavlenko
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*****************************************************************************/
// mapnik
#include <mapnik/debug.hpp>
#include <mapnik/raster_colorizer.hpp>
// stl
#include <limits>
namespace mapnik
{
//! \brief Strings for the colorizer_mode enumeration
static const char *colorizer_mode_strings[] = {
"inherit",
"linear",
"discrete",
"exact",
""
};
IMPLEMENT_ENUM( colorizer_mode, colorizer_mode_strings )
colorizer_stop::colorizer_stop(float value, colorizer_mode mode,
color const& _color,
std::string const& label)
: value_(value)
, mode_(mode)
, color_(_color)
, label_(label)
{
}
colorizer_stop::colorizer_stop(colorizer_stop const& stop)
: value_(stop.value_)
, mode_(stop.mode_)
, color_(stop.color_)
, label_(stop.label_)
{
}
colorizer_stop::~colorizer_stop()
{
}
bool colorizer_stop::operator==(colorizer_stop const& other) const
{
return (value_ == other.value_) &&
(color_ == other.color_) &&
(mode_ == other.mode_) &&
(label_ == other.label_);
}
std::string colorizer_stop::to_string() const
{
std::stringstream ss;
ss << color_.to_string() << " " << value_ << " " << mode_.as_string();
return ss.str();
}
raster_colorizer::raster_colorizer(colorizer_mode mode, color const& _color)
: default_mode_(mode)
, default_color_(_color)
, epsilon_(std::numeric_limits<float>::epsilon())
{
}
raster_colorizer::~raster_colorizer()
{
}
bool raster_colorizer::add_stop(colorizer_stop const& stop)
{
//make sure stops are added in order of value
if(stops_.size())
{
if(stop.get_value() <= stops_.back().get_value())
{
return false;
}
}
stops_.push_back(stop);
return true;
}
void raster_colorizer::colorize(raster_ptr const& raster, Feature const& f) const
{
unsigned *imageData = raster->data_.getData();
int len = raster->data_.width() * raster->data_.height();
bool hasNoData = false;
float noDataValue = 0;
//std::map<std::string,value>::const_iterator fi = Props.find("NODATA");
if (f.has_key("NODATA"))
{
hasNoData = true;
noDataValue = static_cast<float>(f.get("NODATA").to_double());
}
for (int i=0; i<len; ++i)
{
// the GDAL plugin reads single bands as floats
float value = *reinterpret_cast<float *> (&imageData[i]);
if (hasNoData && noDataValue == value)
imageData[i] = color(0,0,0,0).rgba();
else
imageData[i] = get_color(value).rgba();
}
}
inline unsigned interpolate(unsigned start, unsigned end, float fraction)
{
return static_cast<unsigned>(fraction * ((float)end - (float)start) + start);
}
color raster_colorizer::get_color(float value) const
{
int stopCount = stops_.size();
//use default color if no stops
if(stopCount == 0)
{
return default_color_;
}
//1 - Find the stop that the value is in
int stopIdx = -1;
bool foundStopIdx = false;
for(int i=0; i<stopCount; ++i)
{
if(value < stops_[i].get_value())
{
stopIdx = i-1;
foundStopIdx = true;
break;
}
}
if(!foundStopIdx)
{
stopIdx = stopCount-1;
}
//2 - Find the next stop
int nextStopIdx = stopIdx + 1;
if(nextStopIdx >= stopCount)
{
//there is no next stop
nextStopIdx = stopCount - 1;
}
//3 - Work out the mode
colorizer_mode stopMode;
if( stopIdx == -1 )
{
//before the first stop
stopMode = default_mode_;
}
else
{
stopMode = stops_[stopIdx].get_mode();
if(stopMode == COLORIZER_INHERIT)
{
stopMode = default_mode_;
}
}
//4 - Calculate the colour
color stopColor;
color nextStopColor;
float stopValue = 0;
float nextStopValue = 0;
color outputColor = get_default_color();
if(stopIdx == -1)
{
stopColor = default_color_;
nextStopColor = stops_[nextStopIdx].get_color();
stopValue = value;
nextStopValue = stops_[nextStopIdx].get_value();
}
else
{
stopColor = stops_[stopIdx].get_color();
nextStopColor = stops_[nextStopIdx].get_color();
stopValue = stops_[stopIdx].get_value();
nextStopValue = stops_[nextStopIdx].get_value();
}
switch(stopMode)
{
case COLORIZER_LINEAR:
{
//deal with this separately so we don't have to worry about div0
if(nextStopValue == stopValue)
{
outputColor = stopColor;
}
else
{
float fraction = (value - stopValue) / (nextStopValue - stopValue);
unsigned r = interpolate(stopColor.red(), nextStopColor.red(),fraction);
unsigned g = interpolate(stopColor.green(), nextStopColor.green(),fraction);
unsigned b = interpolate(stopColor.blue(), nextStopColor.blue(),fraction);
unsigned a = interpolate(stopColor.alpha(), nextStopColor.alpha(),fraction);
outputColor.set_red(r);
outputColor.set_green(g);
outputColor.set_blue(b);
outputColor.set_alpha(a);
}
}
break;
case COLORIZER_DISCRETE:
outputColor = stopColor;
break;
case COLORIZER_EXACT:
default:
//approximately equal (within epsilon)
if(fabs(value - stopValue) < epsilon_)
{
outputColor = stopColor;
}
else
{
outputColor = default_color_;
}
break;
}
/*
MAPNIK_LOG_DEBUG(raster_colorizer) << "raster_colorizer: get_color " << value;
MAPNIK_LOG_DEBUG(raster_colorizer) << "\tstopIdx: " << stopIdx;
MAPNIK_LOG_DEBUG(raster_colorizer) << "\tnextStopIdx: " << nextStopIdx;
MAPNIK_LOG_DEBUG(raster_colorizer) << "\tstopValue: " << stopValue;
MAPNIK_LOG_DEBUG(raster_colorizer) << "\tnextStopValue: " << nextStopValue;
MAPNIK_LOG_DEBUG(raster_colorizer) << "\tstopColor: " << stopColor.to_string();
MAPNIK_LOG_DEBUG(raster_colorizer) << "\tnextStopColor: " << nextStopColor.to_string();
MAPNIK_LOG_DEBUG(raster_colorizer) << "\tstopMode: " << stopMode.as_string();
MAPNIK_LOG_DEBUG(raster_colorizer) << "\toutputColor: " << outputColor.to_string();
*/
return outputColor;
}
}
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