From 189da15810deabd739d7c11c6e95fea55739fe60 Mon Sep 17 00:00:00 2001
From: Thomas White <taw@physics.org>
Date: Sat, 1 Aug 2020 15:13:49 +0200
Subject: Initial import from archive

---
 src/png-file.c | 125 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 125 insertions(+)
 create mode 100644 src/png-file.c

(limited to 'src/png-file.c')

diff --git a/src/png-file.c b/src/png-file.c
new file mode 100644
index 0000000..09925a7
--- /dev/null
+++ b/src/png-file.c
@@ -0,0 +1,125 @@
+/*
+ * png-file.c
+ *
+ * PNG output
+ *
+ * (c) 2006-2007 Thomas White <taw27@cam.ac.uk>
+ *
+ *  synth2d - Two-Dimensional Crystallographic Fourier Synthesis
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <stdio.h>
+#include <png.h>
+#include <math.h>
+#include <stdlib.h>
+#include <fftw3.h>
+
+#include "data.h"
+#include "colwheel.h"
+#include "renderer.h"
+
+int png_write_real(const char *filename, fftw_complex *out, double brightness, double gamma_angle, int width, int height, int nx, int ny) {
+
+	FILE *fh;
+	png_structp png_ptr;
+	png_infop info_ptr;
+	png_bytep *row_pointers;
+	int xn, yn;
+	int width_n, height_n;
+	ComplexArray cxar;
+	
+	fh = fopen(filename, "wb");
+	if (!fh) {
+		fprintf(stderr, "Couldn't open output file.\n");
+		return 1;
+	}
+	png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+	if ( !png_ptr ) {
+		fprintf(stderr, "Couldn't create PNG write structure.\n");
+		fclose(fh);
+		return 1;
+	}	
+	info_ptr = png_create_info_struct(png_ptr);
+	if ( !info_ptr ) {
+		png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
+		fprintf(stderr, "Couldn't create PNG info structure.\n");
+		fclose(fh);
+		return 1;
+	}	
+	if ( setjmp(png_jmpbuf(png_ptr)) ) {
+		png_destroy_write_struct(&png_ptr, &info_ptr);
+		fclose(fh);
+		fprintf(stderr, "PNG write failed.\n");
+		return 1;
+	}	
+	png_init_io(png_ptr, fh);
+	
+	width_n = (int)renderer_width(width, height, gamma_angle, nx, ny);
+	height_n = (int)renderer_height(width, height, gamma_angle, nx, ny);
+	cxar = renderer_draw(out, width, height, gamma_angle, nx, ny);
+
+	png_set_IHDR(png_ptr, info_ptr, width_n, height_n, 8, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,
+		PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+	
+	/* Write the image data */
+	row_pointers = malloc(height_n*sizeof(png_bytep *));
+
+	for ( yn=0; yn<height_n; yn++ ) {
+	
+		row_pointers[yn] = malloc(width_n*3);
+		for ( xn=0; xn<width_n; xn++ ) {
+			row_pointers[yn][3*xn] = 0;
+			row_pointers[yn][3*xn+1] = 0;
+			row_pointers[yn][3*xn+2] = 0;
+		}
+		
+	}
+
+	for ( yn=0; yn<height_n; yn++ ) {
+		for ( xn=0; xn<width_n; xn++ ) {
+		
+			double re, im, am, ph;
+			
+			re = cxar.re[xn+width_n*yn];
+			im = cxar.im[xn+width_n*yn];
+			am = sqrt(re*re + im*im) / brightness;
+			ph = atan2(im, re);
+			if ( am > 1 ) am = 1;
+			
+			row_pointers[yn][3*xn] = (png_byte)255*colwheel_red(am, ph);
+			row_pointers[yn][3*xn+1] = (png_byte)255*colwheel_green(am, ph);
+			row_pointers[yn][3*xn+2] = (png_byte)255*colwheel_blue(am, ph);
+			
+		}
+	}
+	
+	for ( yn=0; yn<height_n/2+1; yn++ ) {
+		png_bytep scratch;
+		scratch = row_pointers[yn];
+		row_pointers[yn] = row_pointers[height_n-yn-1];
+		row_pointers[height_n-yn-1] = scratch;
+	}
+	
+	png_set_rows(png_ptr, info_ptr, row_pointers);
+	png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
+	
+	png_destroy_write_struct(&png_ptr, &info_ptr);
+	for ( yn=0; yn<height_n; yn++ ) {
+		free(row_pointers[yn]);
+	}
+	free(row_pointers);
+	fclose(fh);
+	
+	return 0;
+
+}
+
+int png_write(const char *filename, fftw_complex *out, double norm, int nx, int ny) {
+	return png_write_real(filename, out, norm, data_gamma(), data_width(), data_height(), nx, ny);
+}
+
-- 
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