Scroll API.

3 files changed, 30 insertions, 1 deletions

diff --git a/pugl/pugl.h b/pugl/pugl.h
index a764620..f173525 100644
--- a/pugl/pugl.h
+++ b/pugl/pugl.h
@@ -55,6 +55,7 @@ typedef void (*PuglMouseFunc)(PuglWindow* handle,
                               int button, bool down,
                               int x, int y);
 typedef void (*PuglReshapeFunc)(PuglWindow* handle, int width, int height);
+typedef void (*PuglScrollFunc)(PuglWindow* handle, int dx, int dy);
 
 /**
    Create a new GL window.
@@ -120,6 +121,12 @@ void
 puglSetMouseFunc(PuglWindow* window, PuglMouseFunc mouseFunc);
 
 /**
+   Set the function to call on scroll events.
+*/
+void
+puglSetScrollFunc(PuglWindow* window, PuglScrollFunc scrollFunc);
+
+/**
    Set the function to call when the window size changes.
 */
 void
diff --git a/pugl/pugl_internal.h b/pugl/pugl_internal.h
index 8a7b217..3685522 100644
--- a/pugl/pugl_internal.h
+++ b/pugl/pugl_internal.h
@@ -35,6 +35,7 @@ struct PuglWindowImpl {
 	PuglMotionFunc   motionFunc;
 	PuglMouseFunc    mouseFunc;
 	PuglReshapeFunc  reshapeFunc;
+	PuglScrollFunc   scrollFunc;
 
 	PuglPlatformData* impl;
 
@@ -90,3 +91,9 @@ puglSetReshapeFunc(PuglWindow* window, PuglReshapeFunc reshapeFunc)
 {
 	window->reshapeFunc = reshapeFunc;
 }
+
+void
+puglSetScrollFunc(PuglWindow* window, PuglScrollFunc scrollFunc)
+{
+	window->scrollFunc = scrollFunc;
+}
diff --git a/pugl/pugl_x11.c b/pugl/pugl_x11.c
index d8685b2..735cdb1 100644
--- a/pugl/pugl_x11.c
+++ b/pugl/pugl_x11.c
@@ -238,8 +238,23 @@ puglProcessEvents(PuglWindow* win)
 			}
 			break;
 		case ButtonPress:
+			if (event.xbutton.button >= 4 && event.xbutton.button <= 7) {
+				if (win->scrollFunc) {
+					int dx = 0, dy = 0;
+					switch (event.xbutton.button) {
+					case 4: dy =  1; break;
+					case 5: dy = -1; break;
+					case 6: dx = -1; break;
+					case 7: dx =  1; break;
+					}
+					win->scrollFunc(win, dx, dy);
+				}
+				break;
+			}
+			// nobreak
 		case ButtonRelease:
-			if (win->mouseFunc) {
+			if (win->mouseFunc &&
+			    (event.xbutton.button < 4 || event.xbutton.button > 7)) {
 				win->mouseFunc(win,
 				               event.xbutton.button, event.type == ButtonPress,
 				               event.xbutton.x, event.xbutton.y);