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handle NODATA for rgb and grey images in gdal.input - closes #727

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This commit is contained in:
Dane Springmeyer 2011-03-11 21:28:18 +00:00
parent f9040c6026
commit b8663b67e3
2 changed files with 56 additions and 2 deletions
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2
CHANGELOG
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@ -14,6 +14,8 @@ For a complete change history, see the SVN log.
Mapnik Trunk
------------
- Support for NODATA values with grey and rgb images in GDAL plugin (#727)
- Print warning if invalid XML property names are used (#110)
- Made XML property names use consistent dashes, never underscores (#644)

54
plugins/input/gdal/gdal_featureset.cpp
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@ -290,18 +290,68 @@ feature_ptr gdal_featureset::get_feature(mapnik::query const& q)
#ifdef MAPNIK_DEBUG
std::clog << "GDAL Plugin: processing rgb bands..." << std::endl;
#endif
int hasNoData;
float nodata = red->GetNoDataValue(&hasNoData);
GDALColorTable *color_table = red->GetColorTable();
if (!alpha && hasNoData && !color_table)
{
// first read the data in and create an alpha channel from the nodata values
float *imageData = (float*)image.getBytes();
red->RasterIO(GF_Read, x_off, y_off, width, height,
imageData, image.width(), image.height(),
GDT_Float32, 0, 0);
int len = image.width() * image.height();
for (int i=0; i<len; ++i)
{
if (nodata == imageData[i])
*reinterpret_cast<unsigned *> (&imageData[i]) = 0;
else
*reinterpret_cast<unsigned *> (&imageData[i]) = 0xFFFFFFFF;
}
}
red->RasterIO(GF_Read,x_off,y_off,width,height,image.getBytes() + 0,
image.width(),image.height(),GDT_Byte,4,4*image.width());
green->RasterIO(GF_Read,x_off,y_off,width,height,image.getBytes() + 1,
image.width(),image.height(),GDT_Byte,4,4*image.width());
blue->RasterIO(GF_Read,x_off,y_off,width,height,image.getBytes() + 2,
image.width(),image.height(),GDT_Byte,4,4*image.width());
}
else if (grey)
{
#ifdef MAPNIK_DEBUG
std::clog << "GDAL Plugin: processing gray band..." << std::endl;
#endif
int hasNoData;
float nodata = grey->GetNoDataValue(&hasNoData);
GDALColorTable *color_table = grey->GetColorTable();
if (hasNoData && !color_table)
{
#ifdef MAPNIK_DEBUG
std::clog << "\tno data value for layer: " << nodata << std::endl;
#endif
// first read the data in and create an alpha channel from the nodata values
float *imageData = (float*)image.getBytes();
grey->RasterIO(GF_Read, x_off, y_off, width, height,
imageData, image.width(), image.height(),
GDT_Float32, 0, 0);
int len = image.width() * image.height();
for (int i=0; i<len; ++i)
{
if (nodata == imageData[i])
*reinterpret_cast<unsigned *> (&imageData[i]) = 0;
else
*reinterpret_cast<unsigned *> (&imageData[i]) = 0xFFFFFFFF;
}
}
grey->RasterIO(GF_Read,x_off,y_off,width,height,image.getBytes() + 0,
image.width(),image.height(),GDT_Byte, 4, 4 * image.width());
@ -310,9 +360,11 @@ feature_ptr gdal_featureset::get_feature(mapnik::query const& q)
grey->RasterIO(GF_Read,x_off,y_off,width,height,image.getBytes() + 2,
image.width(),image.height(),GDT_Byte, 4, 4 * image.width());
GDALColorTable *color_table = grey->GetColorTable();
if (color_table)
{
#ifdef MAPNIK_DEBUG
std::clog << "GDAL Plugin: Loading colour table..." << std::endl;
#endif
for (unsigned y = 0; y < image.height(); ++y)
{
unsigned int* row = image.getRow(y);