Multitouch trackpad 2 fingers gestures implementation

- 2 fingers scroll (MOUSEPAN / GHOST_kTrackpadEventScroll event) pans/scrolls the view
- 2 fingers pinch (MOUSEZOOM / GHOST_kTrackpadEventMagnify event) zooms the view
And in 3D view:
- alt + 2 fingers scroll rotates the view
- 2 fingers rotation (MOUSEROTATE / GHOST_kTrackpadEventRotate) orbits the view.

The implementation uses a new GHOST event type: GHOST_kEventTrackpad, that is then dispatched as Blender MOUSEPAN, MOUSEZOOM
or MOUSEROTATE events.

This is currently fully implemented for OSX (GHOST Cocoa fires the new events), with auto-detection of the source peripheral, so that a regular mouse still sends MOUSEWHEEL events.

2 files changed, 33 insertions, 4 deletions

diff --git a/source/blender/editors/space_image/image_ops.c b/source/blender/editors/space_image/image_ops.c
index 827b2ddeac2..cef92153725 100644
--- a/source/blender/editors/space_image/image_ops.c
+++ b/source/blender/editors/space_image/image_ops.c
@@ -214,8 +214,21 @@ static int view_pan_exec(bContext *C, wmOperator *op)
 
 static int view_pan_invoke(bContext *C, wmOperator *op, wmEvent *event)
 {
-	view_pan_init(C, op, event);
-	return OPERATOR_RUNNING_MODAL;
+	if (event->type == MOUSEPAN) {
+		SpaceImage *sima= CTX_wm_space_image(C);
+		float offset[2];
+		
+		offset[0]= (event->x - event->prevx)/sima->zoom;
+		offset[1]= (event->y - event->prevy)/sima->zoom;
+		RNA_float_set_array(op->ptr, "offset", offset);
+
+		view_pan_exec(C, op);
+		return OPERATOR_FINISHED;
+	}
+	else {
+		view_pan_init(C, op, event);
+		return OPERATOR_RUNNING_MODAL;
+	}
 }
 
 static int view_pan_modal(bContext *C, wmOperator *op, wmEvent *event)
@@ -331,8 +344,22 @@ static int view_zoom_exec(bContext *C, wmOperator *op)
 
 static int view_zoom_invoke(bContext *C, wmOperator *op, wmEvent *event)
 {
-	view_zoom_init(C, op, event);
-	return OPERATOR_RUNNING_MODAL;
+	if (event->type == MOUSEZOOM) {
+		SpaceImage *sima= CTX_wm_space_image(C);
+		ARegion *ar= CTX_wm_region(C);
+		float factor;
+		
+		factor= 1.0 + (event->x-event->prevx+event->y-event->prevy)/300.0f;
+		RNA_float_set(op->ptr, "factor", factor);
+		sima_zoom_set(sima, ar, sima->zoom*factor);
+		ED_area_tag_redraw(CTX_wm_area(C));
+		
+		return OPERATOR_FINISHED;
+	}
+	else {
+		view_zoom_init(C, op, event);
+		return OPERATOR_RUNNING_MODAL;
+	}
 }
 
 static int view_zoom_modal(bContext *C, wmOperator *op, wmEvent *event)
diff --git a/source/blender/editors/space_image/space_image.c b/source/blender/editors/space_image/space_image.c
index 4622962bac5..6c325d9722f 100644
--- a/source/blender/editors/space_image/space_image.c
+++ b/source/blender/editors/space_image/space_image.c
@@ -219,12 +219,14 @@ void image_keymap(struct wmKeyConfig *keyconf)
 	WM_keymap_add_item(keymap, "IMAGE_OT_view_all", HOMEKEY, KM_PRESS, 0, 0);
 	WM_keymap_add_item(keymap, "IMAGE_OT_view_selected", PADPERIOD, KM_PRESS, 0, 0);
 	WM_keymap_add_item(keymap, "IMAGE_OT_view_pan", MIDDLEMOUSE, KM_PRESS, 0, 0);
+	WM_keymap_add_item(keymap, "IMAGE_OT_view_pan", MOUSEPAN, 0, 0, 0);
 
 	WM_keymap_add_item(keymap, "IMAGE_OT_view_zoom_in", WHEELINMOUSE, KM_PRESS, 0, 0);
 	WM_keymap_add_item(keymap, "IMAGE_OT_view_zoom_out", WHEELOUTMOUSE, KM_PRESS, 0, 0);
 	WM_keymap_add_item(keymap, "IMAGE_OT_view_zoom_in", PADPLUSKEY, KM_PRESS, 0, 0);
 	WM_keymap_add_item(keymap, "IMAGE_OT_view_zoom_out", PADMINUS, KM_PRESS, 0, 0);
 	WM_keymap_add_item(keymap, "IMAGE_OT_view_zoom", MIDDLEMOUSE, KM_PRESS, KM_CTRL, 0);
+	WM_keymap_add_item(keymap, "IMAGE_OT_view_zoom", MOUSEZOOM, 0, 0, 0);
 
 	RNA_float_set(WM_keymap_add_item(keymap, "IMAGE_OT_view_zoom_ratio", PAD8, KM_PRESS, KM_SHIFT, 0)->ptr, "ratio", 8.0f);
 	RNA_float_set(WM_keymap_add_item(keymap, "IMAGE_OT_view_zoom_ratio", PAD4, KM_PRESS, KM_SHIFT, 0)->ptr, "ratio", 4.0f);