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/colwheel.c | 153 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 153 insertions(+)
 create mode 100644 src/colwheel.c

(limited to 'src/colwheel.c')

diff --git a/src/colwheel.c b/src/colwheel.c
new file mode 100644
index 0000000..95f551c
--- /dev/null
+++ b/src/colwheel.c
@@ -0,0 +1,153 @@
+/*
+ * colwheel.c
+ *
+ * Colour wheel definition and visualisation
+ *
+ * (c) 2006-2007 Thomas White <taw27@cam.ac.uk>
+ *
+ *  Synth2D - two-dimensional Fourier synthesis
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <gtk/gtk.h>
+#include <math.h>
+#include <stdlib.h>
+#include <fftw3.h>
+
+#include "displaywindow.h"
+
+#define COLWHEEL_WIDTH 256
+#define COLWHEEL_SIZE ((COLWHEEL_WIDTH)-1)
+#define COLWHEEL_HALF ((COLWHEEL_WIDTH/2)-1)
+
+#define rad2deg(a) ((a)*180.0/M_PI)
+#define deg2rad(a) ((a)*M_PI/180.0)
+
+gint colwheel_show(GtkWidget *widget, gpointer data) {
+
+	GtkWidget *colwheel_window;
+	GdkPixbuf *colwheel_pixbuf;
+	GtkWidget *colwheel_pixmap_widget;
+	fftw_complex *colwheel;
+
+	unsigned int x, y;
+	double am, ph;
+
+	/* This isn't being transformed, so no need to use fftw_malloc() */
+	colwheel = malloc(COLWHEEL_SIZE*COLWHEEL_SIZE*sizeof(fftw_complex));
+	for ( x=0; x<COLWHEEL_SIZE; x++ ) {
+		for ( y=0; y<COLWHEEL_SIZE; y++ ) {
+			colwheel[y + COLWHEEL_SIZE*x][0] = 0;
+			colwheel[y + COLWHEEL_SIZE*x][1] = 0;
+		}
+	}
+
+	/* Plot out a disc containing smoothly varying amplitude and phase */
+	for ( am=0.0; am<1.0; am+=(1.0/COLWHEEL_SIZE) ) {
+		for ( ph=0.0; ph<2.0*M_PI; ph+=1.0/(2.0*M_PI*(double)COLWHEEL_SIZE) ) {
+			x = (unsigned int)(COLWHEEL_HALF + (COLWHEEL_HALF*am*cos(ph)));
+			y = (unsigned int)(COLWHEEL_HALF + (COLWHEEL_HALF*am*sin(ph)));
+			colwheel[(COLWHEEL_SIZE-1-y) + COLWHEEL_SIZE*(COLWHEEL_SIZE-1-x)][0] = am*cos(ph);
+			colwheel[(COLWHEEL_SIZE-1-y) + COLWHEEL_SIZE*(COLWHEEL_SIZE-1-x)][1] = am*sin(ph);
+		}
+	}
+
+	/* Draw a line to remind the user where zero phase is */
+	for ( x=COLWHEEL_HALF+1; x<COLWHEEL_SIZE; x++ ) {
+		colwheel[COLWHEEL_HALF + COLWHEEL_SIZE*(COLWHEEL_SIZE-1-x)][0] = 0;
+		colwheel[COLWHEEL_HALF + COLWHEEL_SIZE*(COLWHEEL_SIZE-1-x)][1] = 0;
+	}
+
+	colwheel_window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
+	gtk_window_set_title(GTK_WINDOW(colwheel_window), "Colour Wheel");
+	colwheel_pixbuf = displaywindow_render_pixbuf(colwheel, 1, COLWHEEL_SIZE, COLWHEEL_SIZE, M_PI_2, 1, 1);
+	free(colwheel);
+	colwheel_pixmap_widget = gtk_image_new_from_pixbuf(colwheel_pixbuf);
+	gtk_container_add(GTK_CONTAINER(colwheel_window), colwheel_pixmap_widget);
+	gtk_widget_show_all(colwheel_window);
+
+	return 0;
+
+}
+
+double colwheel_blue(double am, double ph) {
+
+	double f;
+	unsigned int hi;
+	double d;
+
+	ph = rad2deg(ph);		/* Convert to degrees */
+	ph += 180.0;			/* Rotation of colour wheel */
+	if ( ph >= 360.0 ) ph = 0.0;
+	d = ph / 60.0;
+
+	hi = floor(d);	/* Divide the colour wheel into six sections */
+	f = d - hi;	/* Distance into the current section of the colour wheel */
+	if ( hi == 6 ) hi = 0;
+	switch ( hi ) {
+		case 0 : return am;
+		case 1 : return am;
+		case 2 : return am*(1.0-f);
+		case 3 : return 0.0;
+		case 4 : return am*f/2.0;
+		case 5 : return am/2.0+am*f/2.0;
+		default : return 0.0;
+	}
+
+}
+
+double colwheel_green(double am, double ph) {
+
+	double f;
+	unsigned int hi;
+	double d;
+
+	ph = rad2deg(ph);		/* Convert to degrees */
+	ph += 180.0;			/* Rotation of colour wheel */
+	if ( ph >= 360.0 ) ph = 0.0;
+	d = ph / 60.0;
+
+	hi = floor(d);	/* Divide the colour wheel into six sections */
+	f = d - hi;	/* Distance into the current section of the colour wheel */
+	if ( hi == 6 ) hi = 0;
+	switch ( hi ) {
+		case 0 : return am*f/2.0;
+		case 1 : return am/2.0+am*f/2.0;
+		case 2 : return am;
+		case 3 : return am*(1.0-f);
+		case 4 : return 0.0;
+		case 5 : return 0.0;
+		default : return 0.0;
+	}
+
+}
+
+double colwheel_red(double am, double ph) {
+
+	double f;
+	unsigned int hi;
+	double d;
+
+	ph = rad2deg(ph);		/* Convert to degrees */
+	ph += 180.0;			/* Rotation of colour wheel */
+	if ( ph >= 360.0 ) ph = 0.0;
+	d = ph / 60.0;
+
+	hi = floor(d);	/* Divide the colour wheel into six sections */
+	f = d - hi;	/* Distance into the current section of the colour wheel */
+	if ( hi == 6 ) hi = 0;
+	switch ( hi ) {
+		case 0 : return 0.0;
+		case 1 : return 0.0;
+		case 2 : return 0.0;
+		case 3 : return am*f;
+		case 4 : return am;
+		case 5 : return am*(1.0-f);
+		default : return 0.0;
+	}
+
+}
-- 
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