Added zooming with the mouse wheel. The mouse wheel will zoom in or out by 10% of the screen pixels with the focus as the center of the window.

7 files changed, 149 insertions, 44 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 38626c7..3bb95ee 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -7,6 +7,8 @@ exp004viz_SOURCES = \
         controller/exp004processhits.c \
         controller/exp004reshape.c \
         controller/keyboard.c \
+        controller/mousewheel.c \
+        controller/performzoom.c \
         controller/selection_from_db.c \
         controller/selsave.c \
         controller/set_ortho.c \
@@ -36,6 +38,8 @@ noinst_HEADERS = \
         controller/exp004processhits.h \
         controller/exp004reshape.h \
         controller/keyboard.h \
+        controller/mousewheel.h \
+        controller/performzoom.h \
         controller/selection_from_db.h \
         controller/selsave.h \
         controller/set_ortho.h \
diff --git a/src/controller/exp004mouse.c b/src/controller/exp004mouse.c
index 17ff19c..cf09bef 100644
--- a/src/controller/exp004mouse.c
+++ b/src/controller/exp004mouse.c
@@ -1,6 +1,7 @@
 #include "exp004mouse.h"
 #include "exp004processhits.h"
 #include "exp004reshape.h"
+#include "performzoom.h"
 #include "set_ortho.h"
 #include "../view/exp004geometry.h"
 #include "../view/exp004state0.h"
@@ -28,53 +29,19 @@ exp004mouse (int button, int state, int x, int y)
           if (x == S.selection.x || y == S.selection.y)
             return;
 
-          /*
-           * Convert the selection boundary from window coordinates to
-           * world coordinates.
-           */
-          glMatrixMode (GL_MODELVIEW);
-          glLoadIdentity ();
-          GLdouble model[16];
-          glGetDoublev (GL_MODELVIEW_MATRIX, model);
-          GLdouble projection[16];
-          glGetDoublev (GL_PROJECTION_MATRIX, projection);
           GLint viewport[4];
           glGetIntegerv (GL_VIEWPORT, viewport);
 
-          check_error (__FILE__, __LINE__);
-
-          GLdouble start_position[3];
-          gluUnProject (S.selection.x,
-                        viewport[3] - S.selection.y,
-                        0,
-                        model,
-                        projection,
-                        viewport,
-                        &start_position[0],
-                        &start_position[1], &start_position[2]);
-
-          check_error (__FILE__, __LINE__);
-
-          GLdouble end_position[3];
-          gluUnProject (x,
-                        viewport[3] - y,
-                        0,
-                        model,
-                        projection,
-                        viewport,
-                        &end_position[0], &end_position[1], &end_position[2]);
-
-          check_error (__FILE__, __LINE__);
-
-          S.zoom.active = true;
-          S.zoom.coords[0] = fmin (start_position[0], end_position[0]);
-          S.zoom.coords[1] = fmax (start_position[0], end_position[0]);
-          S.zoom.coords[2] = fmin (start_position[1], end_position[1]);
-          S.zoom.coords[3] = fmax (start_position[1], end_position[1]);
-
-          exp004reshape (S.viewport.w, S.viewport.h);
-
-          glutPostRedisplay ();
+          printf ("Zooming to: %i, %i, %i, %i\n", 
+                  S.selection.x, 
+                  viewport[3] - S.selection.y, 
+                  x, 
+                  viewport[3] - y);
+        
+          performzoom (S.selection.x, 
+                       viewport[3] - S.selection.y, 
+                       x, 
+                       viewport[3] - y);
         }
 
       /*
diff --git a/src/controller/mousewheel.c b/src/controller/mousewheel.c
new file mode 100644
index 0000000..c9ac742
--- a/dev/null
+++ b/src/controller/mousewheel.c
@@ -0,0 +1,45 @@
+#include "mousewheel.h"
+#include "performzoom.h"
+#include <GL/glut.h>
+
+void 
+mousewheel (int button, int dir, int x, int y)
+{
+  /*
+   * Get the current coordinates, substract some fixed amount and
+   * then perform the zoom.
+   */
+  GLint viewport[4];
+  glGetIntegerv (GL_VIEWPORT, viewport);
+
+  /*
+   * The step size could be either a fixed number of pixels or a percentage.
+   */
+  //  int step = 5;
+  int step = (viewport[3] - viewport[1]) * 0.10;
+
+  /*
+   * Not that the focus of the zoom is currently the center of the
+   * window but could alternatively be the mouse pointer's position.
+   */
+
+  // Zoom in
+  if (dir > 0)
+    {
+      performzoom (step,
+                   step,
+                   viewport[3] - step,
+                           viewport[3] - step);            
+    }
+
+  // Zoom out
+  else
+    {
+      performzoom (-step,
+                   -step,
+                   viewport[3] + step,
+                           viewport[3] + step);            
+    }
+
+  return;
+}
diff --git a/src/controller/mousewheel.h b/src/controller/mousewheel.h
new file mode 100644
index 0000000..a3944d0
--- a/dev/null
+++ b/src/controller/mousewheel.h
@@ -0,0 +1,11 @@
+#ifndef MOUSEWHEEL_H
+#define MOUSEWHEEL_H
+
+/*
+ * GLUT callback to be called whenever the scroll wheel is scrolled.
+ * Based on code from Ashwin at
+ * http://stackoverflow.com/questions/14378/using-the-mouse-scrollwheel-in-glut/14444.
+ */
+void mousewheel (int, int, int, int);
+
+#endif // MOUSEWHEEL_H
diff --git a/src/controller/performzoom.c b/src/controller/performzoom.c
new file mode 100644
index 0000000..2fed1d2
--- a/dev/null
+++ b/src/controller/performzoom.c
@@ -0,0 +1,65 @@
+#include "performzoom.h"
+#include "exp004reshape.h"
+#include "../util/check_error.h"
+#include "../view/exp004state0.h"
+#include <GL/glut.h>
+#include <math.h>
+
+/*
+ * A simple alias to make the code more readable.
+ */
+#define S exp004state0
+
+void
+performzoom (int x1, int y1, int x2, int y2)
+{
+  /*
+   * Convert the selection boundary from window coordinates to
+   * world coordinates.
+   */
+  glMatrixMode (GL_MODELVIEW);
+  glLoadIdentity ();
+  GLdouble model[16];
+  glGetDoublev (GL_MODELVIEW_MATRIX, model);
+  GLdouble projection[16];
+  glGetDoublev (GL_PROJECTION_MATRIX, projection);
+  GLint viewport[4];
+  glGetIntegerv (GL_VIEWPORT, viewport);
+
+  check_error (__FILE__, __LINE__);
+  
+  GLdouble start_position[3];
+  gluUnProject (x1,
+                y1,
+                0,
+                model,
+                projection,
+                viewport,
+                &start_position[0],
+                &start_position[1], &start_position[2]);
+  
+  check_error (__FILE__, __LINE__);
+  
+  GLdouble end_position[3];
+  gluUnProject (x2,
+                y2,
+                0,
+                model,
+                projection,
+                viewport,
+                &end_position[0], &end_position[1], &end_position[2]);
+  
+  check_error (__FILE__, __LINE__);
+  
+  S.zoom.active = true;
+  S.zoom.coords[0] = fmin (start_position[0], end_position[0]);
+  S.zoom.coords[1] = fmax (start_position[0], end_position[0]);
+  S.zoom.coords[2] = fmin (start_position[1], end_position[1]);
+  S.zoom.coords[3] = fmax (start_position[1], end_position[1]);
+  
+  exp004reshape (S.viewport.w, S.viewport.h);
+  
+  glutPostRedisplay ();
+  
+  return;
+}
diff --git a/src/controller/performzoom.h b/src/controller/performzoom.h
new file mode 100644
index 0000000..323cc20
--- a/dev/null
+++ b/src/controller/performzoom.h
@@ -0,0 +1,9 @@
+#ifndef PERFORMZOOM_H
+#define PERFORMZOOM_H
+
+/*
+ * Perform a zoom operation.
+ */
+void performzoom (int x1, int y1, int x2, int y2);
+
+#endif // PERFORMZOOM_H
diff --git a/src/view/exp004view.c b/src/view/exp004view.c
index 92cb56e..434c016 100644
--- a/src/view/exp004view.c
+++ b/src/view/exp004view.c
@@ -2,10 +2,13 @@
 #include "../controller/exp004mouse.h"
 #include "../controller/exp004reshape.h"
 #include "../controller/keyboard.h"
+#include "../controller/mousewheel.h"
 #include "../db/dbconnect.h"
 #include "exp004init.h"
 #include "exp004state0.h"
 #include "exp004view.h"
+#include <GL/freeglut.h>
+#include <GL/freeglut_ext.h>
 #include <GL/glut.h>
 
 void
@@ -45,6 +48,7 @@ exp004view (void)
   glutDisplayFunc (exp004display);
   glutKeyboardFunc (keyboard);
   glutMouseFunc (exp004mouse);
+  glutMouseWheelFunc (mousewheel);
   glutReshapeFunc (exp004reshape);
 
   return;