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//
// Fl_PNG_Image support functions for the Fast Light Tool Kit (FLTK).
//
// Copyright 2005-2021 by Bill Spitzak and others.
//
// This library is free software. Distribution and use rights are outlined in
// the file "COPYING" which should have been included with this file. If this
// file is missing or damaged, see the license at:
//
// https://www.fltk.org/COPYING.php
//
// Please see the following page on how to report bugs and issues:
//
// https://www.fltk.org/bugs.php
//
#include <config.h>
#include <FL/Fl_PNG_Image.H>
#include <FL/Fl_RGB_Image.H>
#include <FL/fl_string_functions.h>
#include <FL/fl_utf8.h> // fl_fopen()
#include <stdio.h>
#include <time.h> // hack to restore "configure --enable-x11" on macOS ≥ 11
// PNG library include files
extern "C" {
#if defined(HAVE_LIBPNG) && defined(HAVE_LIBZ)
#include <zlib.h>
#ifdef HAVE_PNG_H
#include <png.h>
#else
#include <libpng/png.h>
#endif // HAVE_PNG_H
#endif // HAVE_LIBPNG && HAVE_LIBZ
} // extern "C"
/**
\file fl_write_png.cxx
PNG image support functions.
*/
/**
Write an RGB(A) image to a PNG image file.
This is a very basic and restricted function to create a PNG image file
from an RGB image (Fl_RGB_Image).
The image data must be aligned w/o gaps, i.e. ld() \b MUST be zero or
equal to data_w() * data_h().
The image file is always written with the original image size data_w()
and data_h(), even if the image has been scaled.
Image depth 1 (gray), 2 (gray + alpha channel), 3 (RGB) and 4 (RGBA)
are supported.
\note Currently there is no error handling except for errors when opening
the file. This may be changed in the future.
\param[in] filename Output filename, extension should be '.png'
\param[in] img RGB image to be written
\return success (0) or error code: negative values are errors
\retval 0 success, file has been written
\retval -1 png or zlib library not available
\retval -2 file open error
\see fl_write_png(const char *, int, int, int, const unsigned char *)
*/
int fl_write_png(const char *filename, Fl_RGB_Image *img) {
return fl_write_png(filename,
img->data()[0],
img->data_w(),
img->data_h(),
img->d(),
img->ld());
}
/**
Write raw image data to a PNG image file.
\see fl_write_png(const char *filename, const char *pixels, int w, int h, int d, int ld)
*/
int fl_write_png(const char *filename, const unsigned char *pixels, int w, int h, int d, int ld) {
return fl_write_png(filename, (const char *)pixels, w, h, d, ld);
}
/**
Write raw image data to a PNG image file.
This is a very basic and restricted function to create a PNG image file
from raw image data, e.g. a screenshot.
The image data must be aligned w/o gaps after each row (ld = 0 or ld = w * d)
or \p ld must be the total length of each row, i.e. w * d + gapsize.
If ld == 0 then ld = w * d is assumed.
The total data size must be (w * d + gapsize) * h = ld' * h
where ld' = w * d if ld == 0.
For further restrictions and return values please see
fl_write_png(const char *filename, Fl_RGB_Image *img).
\param[in] filename Output filename, extension should be '.png'
\param[in] pixels Image data
\param[in] w Image data width
\param[in] h Image data height
\param[in] d Image depth: 1 = GRAY, 2 = GRAY + alpha, 3 = RGB, 4 = RGBA
\param[in] ld Line delta: default (0) = w * d
\return success (0) or error code, see ...
\see fl_write_png(const char *filename, Fl_RGB_Image *img)
*/
int fl_write_png(const char *filename, const char *pixels, int w, int h, int d, int ld) {
#if defined(HAVE_LIBPNG) && defined(HAVE_LIBZ)
FILE *fp;
int color_type;
if ((fp = fl_fopen(filename, "wb")) == NULL) {
return -2;
}
switch (d) {
case 1: color_type = PNG_COLOR_TYPE_GRAY; break;
case 2: color_type = PNG_COLOR_TYPE_GRAY_ALPHA; break;
case 3: color_type = PNG_COLOR_TYPE_RGB; break;
case 4: color_type = PNG_COLOR_TYPE_RGB_ALPHA; break;
default: color_type = PNG_COLOR_TYPE_RGB;
}
if (ld == 0)
ld = w * d;
png_structp pptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
png_infop iptr = png_create_info_struct(pptr);
png_bytep ptr = (png_bytep)pixels;
png_init_io(pptr, fp);
png_set_IHDR(pptr, iptr, w, h, 8,
color_type,
PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_DEFAULT,
PNG_FILTER_TYPE_DEFAULT);
png_set_sRGB(pptr, iptr, PNG_sRGB_INTENT_PERCEPTUAL);
double dpi = 300.0;
int dots_per_meter = (int)(dpi / (2.54 / 100.0));
png_set_pHYs(pptr, iptr, dots_per_meter, dots_per_meter, PNG_RESOLUTION_METER);
png_write_info(pptr, iptr);
for (int i = 0; i < h; i++, ptr += ld) {
png_write_row(pptr, ptr);
}
png_write_end(pptr, iptr);
png_destroy_write_struct(&pptr, &iptr);
fclose(fp);
return 0;
#else
return -1;
#endif
}