WSL/SLF GitLab Repository

PNGIO.cc 21.7 KB
Newer Older
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
/***********************************************************************************/
/*  Copyright 2009 WSL Institute for Snow and Avalanche Research    SLF-DAVOS      */
/***********************************************************************************/
/* This file is part of MeteoIO.
    MeteoIO 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 3 of the License, or
    (at your option) any later version.

    MeteoIO 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 MeteoIO.  If not, see <http://www.gnu.org/licenses/>.
*/
#include "PNGIO.h"
#include <meteoio/ResamplingAlgorithms2D.h>
20
#include <meteoio/Graphics.h>
21
22

#include <algorithm>
23
#include <errno.h>
24
25
26
27
28

using namespace std;

namespace mio {
/**
29
 * @page pngio PNGIO
30
 * @section template_format Format
31
32
33
34
 * This plugin write data to the Portable Network Graphics format (see https://secure.wikimedia.org/wikipedia/en/wiki/Portable_Network_Graphics).
 * No data read has been implemented, because reading an existing file would require the exact knowlege of the color gradient that has been used
 * to create it. When writing grids, various color gradients will be used depending on the parameter that the data represents. Nodata values
 * are represented by transparent pixels (transparency is acheived through a transparent color instead of a true alpha channel for size and performance).
35
 * Finally, the naming scheme for meteo grids should be: YYYYMMDDHHmm_{MeteoGrids::Parameters}.png
36
37
 *
 * @section template_units Units
38
 * All units are MKSA except temperatures that are expressed in celcius.
39
40
41
 *
 * @section template_keywords Keywords
 * This plugin uses the following keywords:
42
43
 * - COORDSYS: input coordinate system (see Coords) specified in the [Output] section
 * - COORDPARAM: extra input coordinates parameters (see Coords) specified in the [Output] section
44
45
46
47
48
49
50
 * - GRID2DPATH: meteo grids directory where to read the grids; [Output] section
 * - PNG_LEGEND: plot legend on the side of the graph? (default: true)
 * - PNG_MIN_SIZE: guarantee that a 2D plot will have at least the given size
 * - PNG_MAX_SIZE: guarantee that a 2D plot will have at most the given size
 * - PNG_SCALING: scaling algorithm, either nearest or bilinear (default=bilinear)
 * - PNG_AUTOSCALE: autoscale for the color gradient? (default=true)
 * - PNG_WORLD_FILE: create world file with each file? (default=false)
51
52
 *
 * The size are specified as width followed by height, with the separator being either a space, 'x' or '*'. If a minimum and a maximum size are given, the average of the smallest and largest permissible sizes will be used.
53
54
55
56
57
58
59
60
61
62
63
 * The world file is used for geolocalization and goes alongside the graphics output. By convention,
 * the file has the same name as the image file, with the third letter of the extension jammed with a w: tif->tfw, jpg->jqw.
 * The format is the following:
 * @code
 *    5.000000000000 (size of pixel in x direction)
 *    0.000000000000 (rotation term for row)
 *    0.000000000000 (rotation term for column)
 *    -5.000000000000 (size of pixel in y direction)
 *    492169.690845528910 (x coordinate of centre of upper left pixel in map units)
 *    5426523.318065105000 (y coordinate of centre of upper left pixel in map units)
 * @endcode
64
 *
65
 * @section example Example use
66
67
68
69
70
71
 * @code
 * GRID2D = PNG
 * png_legend = false
 * png_min_size = 400x400
 * png_max_size = 1366*768
 * @endcode
72
73
74
 */

const double PNGIO::plugin_nodata = -999.; //plugin specific nodata value. It can also be read by the plugin (depending on what is appropriate)
75
76
77
const unsigned char PNGIO::channel_depth = 8;
const unsigned char PNGIO::channel_max_color = 255;
const unsigned char PNGIO::transparent_grey = channel_max_color;
78
79
80

PNGIO::PNGIO(void (*delObj)(void*), const Config& i_cfg) : IOInterface(delObj), cfg(i_cfg)
{
81
	setOptions();
82
83
84
85
}

PNGIO::PNGIO(const std::string& configfile) : IOInterface(NULL), cfg(configfile)
{
86
	setOptions();
87
88
89
90
}

PNGIO::PNGIO(const Config& cfgreader) : IOInterface(NULL), cfg(cfgreader)
{
91
92
93
94
95
	setOptions();
}

void PNGIO::setOptions()
{
96
97
	cfg.getValue("COORDSYS", "Output", coordout);
	cfg.getValue("COORDPARAM", "Output", coordoutparam, Config::nothrow);
98
	cfg.getValue("GRID2DPATH", "Output", grid2dpath);
99
100
	//cfg.getValue("TIME_ZONE", "Output", tz_out, Config::nothrow);

101
102
103
	//get size specifications
	std::string min_size, max_size;
	min_w = min_h = max_w = max_h = IOUtils::unodata;
104
	cfg.getValue("PNG_MIN_SIZE", "Output", min_size, Config::nothrow);
105
	if(min_size!="") parse_size(min_size, min_w, min_h);
106
	cfg.getValue("PNG_MAX_SIZE", "Output", max_size, Config::nothrow);
107
	if(max_size!="") parse_size(max_size, max_w, max_h);
108

109
	autoscale = true;
110
	cfg.getValue("PNG_AUTOSCALE", "Output", autoscale, Config::nothrow);
111
	has_legend = true;
112
	cfg.getValue("PNG_LEGEND", "Output", has_legend, Config::nothrow);
113
	scaling = "bilinear";
114
	cfg.getValue("PNG_SCALING", "Output", scaling, Config::nothrow);
115
	has_world_file=false;
116
	cfg.getValue("PNG_WORLD_FILE", "Output", has_world_file, Config::nothrow);
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154

	if(has_legend) { //we need to save room for the legend
		if(min_w!=IOUtils::unodata) min_w -= legend::getLegendWidth();
		if(max_w!=IOUtils::unodata) max_w -= legend::getLegendWidth();
	}
}

void PNGIO::parse_size(const std::string& size_spec, unsigned int& width, unsigned int& height)
{
	char rest[32] = "";
	if(sscanf(size_spec.c_str(), "%u %u%31s", &width, &height, rest) < 2)
	if(sscanf(size_spec.c_str(), "%u*%u%31s", &width, &height, rest) < 2)
	if(sscanf(size_spec.c_str(), "%ux%u%31s", &width, &height, rest) < 2) {
		std::stringstream ss;
		ss << "Can not parse PNGIO size specification \"" << size_spec << "\"";
		throw InvalidFormatException(ss.str(), AT);
	}
	std::string tmp(rest);
	IOUtils::trim(tmp);
	if ((tmp.length() > 0) && tmp[0] != '#' && tmp[0] != ';') {//if line holds more than one value it's invalid
		std::stringstream ss;
		ss << "Invalid PNGIO size specification \"" << size_spec << "\"";
		throw InvalidFormatException(ss.str(), AT);
	}
}

double PNGIO::getScaleFactor(const double& grid_w, const double& grid_h)
{
	if(grid_w==0 || grid_h==0) {
		return 1.;
	}

	double min_factor = IOUtils::nodata;
	if(min_w!=IOUtils::unodata) { //min_w & min_w are read together
		const double min_w_factor = (double)min_w / (double)grid_w;
		const double min_h_factor = (double)min_h / (double)grid_h;
		min_factor = std::max(min_w_factor, min_h_factor);
	}
155

156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
	double max_factor = IOUtils::nodata;
	if(max_w!=IOUtils::unodata) { //max_w & max_h are read together
		const double max_w_factor = (double)max_w / (double)grid_w;
		const double max_h_factor = (double)max_h / (double)grid_h;
		max_factor = std::min(max_w_factor, max_h_factor);
	}

	if(min_factor==IOUtils::nodata && max_factor==IOUtils::nodata)
		return 1.; //no user given specification
	if(min_factor!=IOUtils::nodata && max_factor!=IOUtils::nodata)
		return (min_factor+max_factor)/2.; //both min & max -> average

	//only one size specification provided -> return its matching factor
	if(min_factor!=IOUtils::nodata)
		return min_factor;
	else
		return max_factor;
173
174
}

175
PNGIO::~PNGIO() throw() {
176
177
178

}

179
180
181
182
183
184
185
void PNGIO::read2DGrid(Grid2DObject&, const std::string&)
{
	//Nothing so far
	throw IOException("Nothing implemented here", AT);
}

void PNGIO::read2DGrid(Grid2DObject&, const MeteoGrids::Parameters& , const Date&)
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
{
	//Nothing so far
	throw IOException("Nothing implemented here", AT);
}

void PNGIO::readDEM(DEMObject& /*dem_out*/)
{
	//Nothing so far
	throw IOException("Nothing implemented here", AT);
}

void PNGIO::readLanduse(Grid2DObject& /*landuse_out*/)
{
	//Nothing so far
	throw IOException("Nothing implemented here", AT);
}

void PNGIO::readAssimilationData(const Date& /*date_in*/, Grid2DObject& /*da_out*/)
{
	//Nothing so far
	throw IOException("Nothing implemented here", AT);
}

void PNGIO::readStationData(const Date&, std::vector<StationData>& /*vecStation*/)
{
	//Nothing so far
	throw IOException("Nothing implemented here", AT);
}

void PNGIO::readMeteoData(const Date& /*dateStart*/, const Date& /*dateEnd*/,
                             std::vector< std::vector<MeteoData> >& /*vecMeteo*/,
                             const size_t&)
{
	//Nothing so far
	throw IOException("Nothing implemented here", AT);
}

void PNGIO::writeMeteoData(const std::vector< std::vector<MeteoData> >& /*vecMeteo*/,
                              const std::string&)
{
	//Nothing so far
	throw IOException("Nothing implemented here", AT);
}

void PNGIO::readSpecialPoints(std::vector<Coords>&)
{
	//Nothing so far
	throw IOException("Nothing implemented here", AT);
}

236
237
Grid2DObject PNGIO::scaleGrid(const Grid2DObject& grid_in)
{ //scale input image
238
	const double factor = getScaleFactor(grid_in.ncols, grid_in.nrows);
239
	if(scaling=="nearest")
240
		return ResamplingAlgorithms2D::NearestNeighbour(grid_in, factor);
241
	else if(scaling=="bilinear")
242
		return ResamplingAlgorithms2D::BilinearResampling(grid_in, factor);
243
244
245
246
247
	else {
		stringstream ss;
		ss << "Grid scaling algorithm \"" << scaling << "\" unknown";
		throw UnknownValueException(ss.str(), AT);
	}
248
}
249

250
void PNGIO::setFile(const std::string& filename, png_structp& png_ptr, png_infop& info_ptr, const unsigned int &width, const unsigned int &height)
251
{
252
253
254
255
	// Open file for writing (binary mode)
	if (!IOUtils::validFileName(filename)) {
		throw InvalidFileNameException(filename, AT);
	}
256
	errno=0;
257
258
	fp = fopen(filename.c_str(), "wb");
	if (fp == NULL) {
259
260
261
		stringstream ss;
		ss << "Error openning file \"" << filename << "\", possible reason: " << strerror(errno);
		throw FileAccessException(ss.str(), AT);
262
263
264
265
266
267
268
269
270
271
272
273
274
275
	}

	// Initialize write structure
	png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
	if (png_ptr == NULL) {
		fclose(fp);
		throw IOException("Could not allocate write structure", AT);
	}

	// Initialize info structure
	info_ptr = png_create_info_struct(png_ptr);
	if (info_ptr == NULL) {
		fclose(fp);
		png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
276
		free(png_ptr);
277
278
279
280
281
		throw IOException("Could not allocate info structure", AT);
	}

	// Setup Exception handling
	if (setjmp(png_jmpbuf(png_ptr))) {
282
283
		closePNG(png_ptr, info_ptr);
		throw IOException("Error during png creation. Can not set jump pointer (I have no clue what it means too!)", AT);
284
285
286
287
	}

	png_init_io(png_ptr, fp);

288
	// Write header (8 bit colour depth). Alpha channel with PNG_COLOR_TYPE_RGB_ALPHA
289
	png_set_IHDR(png_ptr, info_ptr, width, height,
290
	             channel_depth, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
291
	             PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
292
	//set transparent color (ie: cheap transparency: leads to smaller files and shorter run times)
293
	png_color_16 trans_rgb_value = {transparent_grey, transparent_grey, transparent_grey, transparent_grey, transparent_grey};
294
	png_set_tRNS(png_ptr, info_ptr, 0, 0, &trans_rgb_value);
295
296
297
	//set background color to help applications show the picture when no background is present
	png_color_16 background = {channel_max_color, channel_max_color, channel_max_color, channel_max_color, channel_max_color};
	png_set_background(png_ptr, &background, PNG_BACKGROUND_GAMMA_SCREEN, true, 1.0);
298
299
300
301
}

unsigned int PNGIO::setLegend(const unsigned int &ncols, const unsigned int &nrows, const double &min, const double &max, Array2D<double> &legend_array)
{
302
303
304
305
306
	if(has_legend) {
		legend leg(nrows, min, max);
		legend_array = leg.getLegend();
		unsigned int nx, ny;
		legend_array.size(nx,ny);
307
308
309
		return (ncols+nx);
	} else {
		return ncols;
310
	}
311
312
}

313
void PNGIO::writeDataSection(const Grid2DObject &grid, const Array2D<double> &legend_array, const Gradient &gradient, const unsigned int &full_width, const png_structp &png_ptr)
314
{
315
316
	const double ncols = grid.ncols;
	const double nrows = grid.nrows;
317

318
319
	// Allocate memory for one row (3 bytes per pixel - RGB)
	const unsigned char channels = 3;
320
321
322
323
	png_bytep row = (png_bytep)calloc(channels*sizeof(png_byte), full_width);
	if(row==NULL) {
		throw IOException("Can not allocate row memory in PNGIO!", AT);
	}
324
325

	// Write image data
326
	for(int y=nrows-1 ; y>=0 ; y--) {
327
328
329
330
331
		unsigned int x=0;
		for(; x<ncols ; x++) {
			const unsigned int i=x*channels;
			unsigned char r,g,b;
			bool a;
332
			gradient.getColor(grid(x,y), r,g,b,a);
333
			if(a==true) {
334
				row[i]=transparent_grey; row[i+1]=transparent_grey; row[i+2]=transparent_grey;
335
336
337
			} else {
				row[i]=r; row[i+1]=g; row[i+2]=b;
			}
338
		}
339
340
341
342
		for(; x<full_width; x++) {
			const unsigned int i=x*channels;
			unsigned char r,g,b;
			bool a;
343
			gradient.getColor(legend_array(x-ncols,y), r,g,b,a);
344
			if(a==true) {
345
				row[i]=transparent_grey; row[i+1]=transparent_grey; row[i+2]=transparent_grey;
346
347
348
			} else {
				row[i]=r; row[i+1]=g; row[i+2]=b;
			}
349
350
351
		}
		png_write_row(png_ptr, row);
	}
352
353
	png_write_flush(png_ptr);
	png_free(png_ptr, row);
354
355
}

356
void PNGIO::closePNG(png_structp& png_ptr, png_infop& info_ptr)
357
{
358
359
360
361
362
	fclose(fp);
	png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
	png_destroy_write_struct(&png_ptr, &info_ptr);
	free(info_ptr);
	free(png_ptr);
363
364
}

365
void PNGIO::write2DGrid(const Grid2DObject& grid_in, const std::string& filename)
366
{
367
	string full_name = grid2dpath+"/"+filename;
368
369
	//FILE *fp=NULL;
	fp=NULL;
370
371
372
373
374
375
376
377
378
379
	png_structp png_ptr=NULL;
	png_infop info_ptr=NULL;

	//scale input image
	const Grid2DObject grid = scaleGrid(grid_in);
	const double ncols = grid.ncols, nrows = grid.nrows;
	const double min = grid.grid2D.getMin();
	const double max = grid.grid2D.getMax();

	Gradient gradient(Gradient::heat, min, max, autoscale);
380
	gradient.setNrOfLevels(50);
381
382
383
384

	Array2D<double> legend_array; //it will remain empty if there is no legend
	const unsigned int full_width = setLegend(ncols, nrows, min, max, legend_array);

385
	setFile(full_name, png_ptr, info_ptr, full_width, nrows);
386
	if(has_world_file) writeWorldFile(grid, full_name);
387
388
389
390
391
392
393
394

	createMetadata(grid);
	metadata_key.push_back("Title"); //adding generic title
	metadata_text.push_back("Unknown Gridded data");
	writeMetadata(png_ptr, info_ptr);

	writeDataSection(grid, legend_array, gradient, full_width, png_ptr);
	png_write_end(png_ptr, NULL);
395
396

	closePNG(png_ptr, info_ptr);
397
398
}

399
void PNGIO::write2DGrid(const Grid2DObject& grid_in, const MeteoGrids::Parameters& parameter, const Date& date)
400
{
401
402
	std::string filename;
	if(parameter==MeteoGrids::DEM || parameter==MeteoGrids::SLOPE || parameter==MeteoGrids::AZI)
403
		filename = grid2dpath + "/" + MeteoGrids::getParameterName(parameter) + ".png";
404
	else
405
		filename = grid2dpath + "/" + date.toString(Date::NUM) + "_" + MeteoGrids::getParameterName(parameter) + ".png";
406

407
408
	//FILE *fp=NULL;
	fp=NULL;
409
410
411
412
413
414
415
416
417
418
419
	png_structp png_ptr=NULL;
	png_infop info_ptr=NULL;

	//scale input image
	Grid2DObject grid = scaleGrid(grid_in);
	const double ncols = grid.ncols, nrows = grid.nrows;
	double min = grid.grid2D.getMin();
	double max = grid.grid2D.getMax();

	Gradient gradient;
	if(parameter==MeteoGrids::DEM) {
420
421
		if(!autoscale) {
			min = 0.; //we want a 3000 snow line with a full scale legend
422
423
			max = 3500.;
			gradient.set(Gradient::terrain, min, max, autoscale); //max used as snow line reference
424
425
		} else
			gradient.set(Gradient::terrain, min, max, autoscale);
426
427
428
	} else if(parameter==MeteoGrids::SLOPE) {
		gradient.set(Gradient::slope, min, max, autoscale);
	} else if(parameter==MeteoGrids::AZI) {
429
430
431
432
		if(!autoscale) {
			min = 0.;
			max = 360.;
		}
433
434
		gradient.set(Gradient::azi, min, max, autoscale);
	} else if(parameter==MeteoGrids::HS) {
435
436
437
438
		if(!autoscale) {
			min = 0.; max = 3.5;
		}
		gradient.set(Gradient::blue, min, max, autoscale);
439
440
	} else if(parameter==MeteoGrids::TA) {
		grid.grid2D -= Cst::t_water_freezing_pt; //convert to celsius
441
442
443
444
445
446
		if(!autoscale) {
			min = -10.; max = 10.;
		} else {
			min -= Cst::t_water_freezing_pt;
			max -= Cst::t_water_freezing_pt;
		}
447
		gradient.set(Gradient::heat, min, max, autoscale);
448
449
450
451
452
453
454
455
456
	} else if(parameter==MeteoGrids::TSS) {
		grid.grid2D -= Cst::t_water_freezing_pt; //convert to celsius
		if(!autoscale) {
			min = -10.; max = 10.;
		} else {
			min -= Cst::t_water_freezing_pt;
			max -= Cst::t_water_freezing_pt;
		}
		gradient.set(Gradient::freeze, min, max, autoscale);
457
	} else if(parameter==MeteoGrids::RH) {
458
459
460
		if(!autoscale) {
			min = 0.; max = 1.;
		}
461
462
463
464
465
466
		gradient.set(Gradient::bg_isomorphic, min, max, autoscale);
	} else if(parameter==MeteoGrids::ALB) {
		if(!autoscale) {
			min = 0.; max = 1.;
		}
		gradient.set(Gradient::bg_isomorphic, min, max, autoscale);
467
	} else if(parameter==MeteoGrids::SWE) {
468
469
470
471
		if(!autoscale) {
			min = 0.; max = 2000.;
		}
		gradient.set(Gradient::blue, min, max, autoscale);
472
473
474
	} else {
		gradient.set(Gradient::heat, min, max, autoscale);
	}
475
	gradient.setNrOfLevels(30);
476
477

	Array2D<double> legend_array; //it will remain empty if there is no legend
478
	const unsigned int full_width = setLegend(ncols, nrows, min, max, legend_array);
479

480
	setFile(filename, png_ptr, info_ptr, full_width, nrows);
481
	if(has_world_file) writeWorldFile(grid, filename);
482
483
484
485

	createMetadata(grid);
	metadata_key.push_back("Title"); //adding title
	metadata_text.push_back( MeteoGrids::getParameterName(parameter)+" on "+date.toString(Date::ISO) );
486
487
	metadata_key.push_back("Simulation Date");
	metadata_text.push_back( date.toString(Date::ISO) );
488
489
	metadata_key.push_back("Simulation Parameter");
	metadata_text.push_back( MeteoGrids::getParameterName(parameter) );
490
491
492
493
	writeMetadata(png_ptr, info_ptr);

	writeDataSection(grid, legend_array, gradient, full_width, png_ptr);
	png_write_end(png_ptr, NULL);
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529

	closePNG(png_ptr, info_ptr);
	/*fclose(fp);
	png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
	png_destroy_write_struct(&png_ptr, &info_ptr);
	free(info_ptr);
	free(png_ptr);*/
}

void PNGIO::writeWorldFile(const Grid2DObject& grid_in, const std::string& filename)
{
	const string world_file = IOUtils::removeExtension(filename)+".pnw";
	const double cellsize = grid_in.cellsize;
	Coords world_ref=grid_in.llcorner;
	world_ref.setProj(coordout, coordoutparam);
	world_ref.moveByXY(0., grid_in.nrows*cellsize);

	std::ofstream fout;
	fout.open(world_file.c_str());
	if (fout.fail()) {
		throw FileAccessException(world_file, AT);
	}

	try {
		fout << std::setprecision(12) << cellsize << "\n";
		fout << "0.000000000000\n";
		fout << "0.000000000000\n";
		fout << std::setprecision(12) << -cellsize << "\n";
		fout << std::setprecision(12) << world_ref.getEasting() << "\n";
		fout << std::setprecision(12) << world_ref.getNorthing() << "\n";
	} catch(...) {
		fout.close();
		throw FileAccessException("Failed when writing to PNG world file \""+world_file+"\"", AT);
	}

	fout.close();
530
531
}

532
void PNGIO::createMetadata(const Grid2DObject& grid)
533
{
534
535
536
537
	const double lat = grid.llcorner.getLat();
	const double lon = grid.llcorner.getLon();
	stringstream ss;

538
539
540
	metadata_key.clear();
	metadata_text.clear();

541
542
543
544
	metadata_key.push_back("Creation Time");
	Date cr_date;
	cr_date.setFromSys();
	metadata_text.push_back( cr_date.toString(Date::ISO) );
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
	metadata_key.push_back("Author");
	metadata_text.push_back(IOUtils::getLogName());
	metadata_key.push_back("Software");
	metadata_text.push_back("MeteoIO "+getLibVersion());
	metadata_key.push_back("Position");
	metadata_text.push_back("llcorner");
	metadata_key.push_back("Cellsize");
	ss.str(""); ss << fixed << setprecision(2) << grid.cellsize;
	metadata_text.push_back(ss.str());
	metadata_key.push_back("Latitude");
	ss.str(""); ss << fixed << setprecision(6) << lat;
	metadata_text.push_back(ss.str());
	metadata_key.push_back("Longitude");
	ss.str(""); ss << fixed << setprecision(6) << lon;
	metadata_text.push_back(ss.str());
560

561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
	if(lat<0.) {
		metadata_key.push_back("LatitudeRef");
		metadata_text.push_back("S");
		metadata_key.push_back("GPSLatitude");
		metadata_text.push_back(decimal_to_dms(-lat));
	} else {
		metadata_key.push_back("LatitudeRef");
		metadata_text.push_back("N");
		metadata_key.push_back("GPSLatitude");
		metadata_text.push_back(decimal_to_dms(lat));
	}
	if(lon<0.) {
		metadata_key.push_back("LongitudeRef");
		metadata_text.push_back("W");
		metadata_key.push_back("GPSLongitude");
		metadata_text.push_back(decimal_to_dms(-lon));
	} else {
		metadata_key.push_back("LongitudeRef");
		metadata_text.push_back("E");
		metadata_key.push_back("GPSLongitude");
		metadata_text.push_back(decimal_to_dms(lon));
	}
}

void PNGIO::writeMetadata(png_structp &png_ptr, png_infop &info_ptr)
{
	const size_t nr = metadata_key.size();
	png_text *info_text;
	info_text = (png_text *)calloc(sizeof(png_text), nr);
	char **key, **text;
	key = (char**)calloc(sizeof(char)*80, nr);
	text = (char**)calloc(sizeof(char)*80, nr);

	for(size_t ii=0; ii<nr; ii++) {
		key[ii] = (char *)calloc(sizeof(char), 80);
		text[ii] = (char *)calloc(sizeof(char), 80);
		strncpy(key[ii], metadata_key[ii].c_str(), 80);
		strncpy(text[ii], metadata_text[ii].c_str(), 80);
		info_text[ii].key = key[ii];
		info_text[ii].text = text[ii];
		info_text[ii].compression = PNG_TEXT_COMPRESSION_NONE;
	}
603

604
	png_set_text(png_ptr, info_ptr, info_text, nr);
605
606
	png_write_info(png_ptr, info_ptr);

607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
	free(info_text);
	for(size_t ii=0; ii<nr; ii++) {
		free(key[ii]);
		free(text[ii]);
	}
	free(key);
	free(text);
}

std::string PNGIO::decimal_to_dms(const double& decimal) {
	std::stringstream dms;
	const int d = static_cast<int>( floor(decimal) );
	const double m = floor( ((decimal - (double)d)*60.)*100. ) / 100.;
	const double s = 3600.*(decimal - (double)d) - 60.*m;

	dms << d << "/1 " << static_cast<int>(m*100) << "/100 " << fixed << setprecision(6) << s << "/1";
	return dms.str();
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
}

#ifndef _METEOIO_JNI
extern "C"
{
#define COMPILE_PLUGIN
#include "exports.h"

	METEOIO_EXPORT void deleteObject(void* obj) {
		delete reinterpret_cast<PluginObject*>(obj);
	}

	METEOIO_EXPORT void* loadObject(const string& classname, const Config& cfg) {
		if(classname == "PNGIO") {
			//cerr << "Creating dynamic handle for " << classname << endl;
			return new PNGIO(deleteObject, cfg);
		}
		//cerr << "Could not load " << classname << endl;
		return NULL;
	}
}
#endif

} //namespace