Adding plot library

src/main.c

@@ -1,4 +1,4 @@
-#include <gtk/gtk.h>
+#include <gtk/gtk.h> /* libgtk-3-dev */
 #define HANDY_USE_UNSTABLE_API
 #include <handy.h>
 

src/meson.build

@@ -3,6 +3,7 @@ picplanner_sources = [
   'calculations.c',
   'webconnection.c',
   'handler.c',
+  'plot.c',
 ]
 
 picplanner_deps = [

src/picplanner-window.glade

@@ -341,6 +341,20 @@
                 <property name="icon_name">system-search-symbolic</property>
               </packing>
             </child>
+            <child>
+              <object class="GtkButton">
+                <property name="label" translatable="yes">Overviwe</property>
+                <property name="visible">True</property>
+                <property name="can_focus">False</property>
+                <property name="receives_default">False</property>
+              </object>
+              <packing>
+                <property name="name">overview</property>
+                <property name="title" translatable="yes">Overview</property>
+                <property name="icon_name">help-about-symbolic</property>
+                <property name="position">4</property>
+              </packing>
+            </child>
             <child>
               <object class="GtkLabel">
                 <property name="visible">True</property>
@@ -351,7 +365,7 @@
                 <property name="name">sun</property>
                 <property name="title" translatable="yes">Sun</property>
                 <property name="icon_name">weather-clear-symbolic</property>
-                <property name="position">1</property>
+                <property name="position">2</property>
               </packing>
             </child>
             <child>
@@ -364,7 +378,7 @@
                 <property name="name">moon</property>
                 <property name="title" translatable="yes">Moon</property>
                 <property name="icon_name">night-light-symbolic</property>
-                <property name="position">2</property>
+                <property name="position">3</property>
               </packing>
             </child>
             <child>
@@ -378,7 +392,7 @@
                 <property name="name">milkyway</property>
                 <property name="title" translatable="yes">Milky Way</property>
                 <property name="icon_name">help-about-symbolic</property>
-                <property name="position">3</property>
+                <property name="position">4</property>
               </packing>
             </child>
           </object>

src/plot.c

@@ -0,0 +1,43 @@
+#include <plot.h>
+
+double plot_calc_coordinate_x (double a1, double a2, float alpha, float beta) {
+  /* coordinate transformation to transform 3D coordinates into 2D coordinates */
+  double x = (sin(beta)*a1-sin(alpha)*a2)/(cos(alpha)*sin(beta)-sin(alpha)*cos(beta));
+  return x;
+}
+double plot_calc_coordinate_y (double a1, double a2, double a3, float alpha, float beta) {
+  /* coordinate transformation to transform 3D coordinates into 2D coordinates */
+  double y = (-cos(beta)*a1+cos(alpha)*a2)/(cos(alpha)*sin(beta)-sin(alpha)*cos(beta)) + a3;
+  return y;
+}
+void plot_line_to (cairo_t *cr, double a1, double a2, double a3, float alpha, float beta){
+  /* plot a line with automatic transformation from 3D coordinates into 2D */
+  cairo_line_to (cr, plot_calc_coordinate_x (a1, a2, alpha, beta), plot_calc_coordinate_y (a1, a2, a3, alpha, beta));
+}
+void plot_move_to (cairo_t *cr, double a1, double a2, double a3, float alpha, float beta) {
+  /* move cairo starting point with automatic transformation from 3D coordinates into 2D */
+  cairo_move_to (cr, plot_calc_coordinate_x (a1, a2, alpha, beta), plot_calc_coordinate_y (a1, a2, a3, alpha, beta));
+}
+void plot_vector_to (cairo_t *cr, double a1, double a2, double a3, float alpha, float beta) {
+  /* plot a vector with automatic transformation from 3D coordinates into 2D */
+  double current_x = 0;
+  double current_y = 0;
+  double *x_1 = &current_x;
+  double *y_1 = &current_y;
+  double x_2 = plot_calc_coordinate_x (a1, a2, alpha, beta);
+  double y_2 = plot_calc_coordinate_y (a1, a2, a3, alpha, beta);
+
+  cairo_get_current_point (cr, x_1, y_1);
+  double direct_x = x_2-*x_1;
+  double direct_y = y_2-*y_1;
+  double norm = pow(pow(direct_x,2) + pow(direct_y,2), 0.5);
+  direct_x /= norm;
+  direct_y /= norm;
+  g_print("direct_x: %f, direct_y: %f\n", direct_x, direct_y);
+
+  float gamma = 0.5326;
+  cairo_line_to (cr, x_2, y_2);
+  cairo_line_to (cr, x_2+(-direct_x*cos(gamma)+direct_y*sin(gamma))*0.2, y_2+(-direct_y*cos(gamma)-direct_x*sin(gamma))*0.2);
+  cairo_move_to (cr, x_2, y_2);
+  cairo_line_to (cr, x_2+(-direct_x*cos(gamma)-direct_y*sin(gamma))*0.2, y_2+(-direct_y*cos(gamma)+direct_x*sin(gamma))*0.2);
+}

src/plot.h

@@ -0,0 +1,13 @@
+#include <gtk/gtk.h>
+#include <math.h>
+#include <cairo.h>
+
+double plot_calc_coordinate_x (double a1, double a2, float alpha, float beta);
+
+double plot_calc_coordinate_y (double a1, double a2, double a3, float alpha, float beta);
+
+void plot_line_to (cairo_t *cr, double a1, double a2, double a3, float alpha, float beta);
+
+void plot_move_to (cairo_t *cr, double a1, double a2, double a3, float alpha, float beta);
+
+void plot_vector_to (cairo_t *cr, double a1, double a2, double a3, float alpha, float beta);