Unify clamping of frames-per-unit values during zoom; should help with #3514.

git-svn-id: svn://localhost/ardour2/branches/3.0@12796 d708f5d6-7413-0410-9779-e7cbd77b26cf

3 files changed, 43 insertions, 44 deletions

diff --git a/gtk2_ardour/editor.cc b/gtk2_ardour/editor.cc
index ab2f92823c..44548791ea 100644
--- a/gtk2_ardour/editor.cc
+++ b/gtk2_ardour/editor.cc
@@ -917,12 +917,9 @@ Editor::zoom_adjustment_changed ()
 	}
 
 	double fpu = zoom_range_clock->current_duration() / _canvas_width;
-
-	if (fpu < 1.0) {
-		fpu = 1.0;
-		zoom_range_clock->set ((framepos_t) floor (fpu * _canvas_width));
-	} else if (fpu > _session->current_end_frame() / _canvas_width) {
-		fpu = _session->current_end_frame() / _canvas_width;
+	bool clamped = clamp_frames_per_unit (fpu);
+	
+	if (clamped) {
 		zoom_range_clock->set ((framepos_t) floor (fpu * _canvas_width));
 	}
 
@@ -4064,6 +4061,12 @@ Editor::reset_y_origin (double y)
 void
 Editor::reset_zoom (double fpu)
 {
+	clamp_frames_per_unit (fpu);
+
+	if (fpu == frames_per_unit) {
+		return;
+	}
+
 	pending_visual_change.add (VisualChange::ZoomLevel);
 	pending_visual_change.frames_per_unit = fpu;
 	ensure_visual_change_idle_handler ();
@@ -4171,41 +4174,20 @@ Editor::use_visual_state (VisualState& vs)
 	_routes->resume_redisplay ();
 }
 
+/** This is the core function that controls the zoom level of the canvas. It is called
+ *  whenever one or more calls are made to reset_zoom().  It executes in an idle handler.
+ *  @param fpu New frames per unit; should already have been clamped so that it is sensible.
+ */
 void
 Editor::set_frames_per_unit (double fpu)
 {
-	/* this is the core function that controls the zoom level of the canvas. it is called
-	   whenever one or more calls are made to reset_zoom(). it executes in an idle handler.
-	*/
-
-	if (fpu == frames_per_unit) {
-		return;
-	}
-
-	if (fpu < 2.0) {
-		fpu = 2.0;
-	}
-
-
-	/* don't allow zooms that fit more than the maximum number
-	   of frames into an 800 pixel wide space.
-	*/
-
-	if (max_framepos / fpu < 800.0) {
-		return;
-	}
-
-	if (tempo_lines)
+	if (tempo_lines) {
 		tempo_lines->tempo_map_changed();
+	}
 
 	frames_per_unit = fpu;
-	post_zoom ();
-}
 
-void
-Editor::post_zoom ()
-{
-	// convert fpu to frame count
+	/* convert fpu to frame count */
 
 	framepos_t frames = (framepos_t) floor (frames_per_unit * _canvas_width);
 
diff --git a/gtk2_ardour/editor.h b/gtk2_ardour/editor.h
index 5bfc7b127e..7b4b1dcbbf 100644
--- a/gtk2_ardour/editor.h
+++ b/gtk2_ardour/editor.h
@@ -525,7 +525,7 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 	Editing::ZoomFocus zoom_focus;
 
 	void set_frames_per_unit (double);
-	void post_zoom ();
+	bool clamp_frames_per_unit (double &) const;
 
 	Editing::MouseMode mouse_mode;
 	Editing::MouseMode pre_internal_mouse_mode;
@@ -1209,7 +1209,7 @@ class Editor : public PublicEditor, public PBD::ScopedConnectionList, public ARD
 	void temporal_zoom_region (bool both_axes);
 	void zoom_to_region (bool both_axes);
 	void temporal_zoom_session ();
-	void temporal_zoom (gdouble scale);
+	void temporal_zoom (double scale);
 	void temporal_zoom_by_frame (framepos_t start, framepos_t end);
 	void temporal_zoom_to_frame (bool coarser, framepos_t frame);
 
diff --git a/gtk2_ardour/editor_ops.cc b/gtk2_ardour/editor_ops.cc
index eacf0c51bd..46a69ce6af 100644
--- a/gtk2_ardour/editor_ops.cc
+++ b/gtk2_ardour/editor_ops.cc
@@ -1327,14 +1327,30 @@ Editor::tav_zoom_smooth (bool coarser, bool force_all)
 	_routes->resume_redisplay ();
 }
 
+bool
+Editor::clamp_frames_per_unit (double& fpu) const
+{
+	bool clamped = false;
+	
+	if (fpu < 2.0) {
+		fpu = 2.0;
+		clamped = true;
+	}
+
+	if (max_framepos / fpu < 800) {
+		fpu = max_framepos / 800.0;
+		clamped = true;
+	}
+
+	return clamped;
+}
+
 void
 Editor::temporal_zoom_step (bool coarser)
 {
 	ENSURE_GUI_THREAD (*this, &Editor::temporal_zoom_step, coarser)
 
-	double nfpu;
-
-	nfpu = frames_per_unit;
+	double nfpu = frames_per_unit;
 
 	if (coarser) {
 		nfpu = min (9e6, nfpu * 1.61803399);
@@ -1346,9 +1362,11 @@ Editor::temporal_zoom_step (bool coarser)
 }
 
 void
-Editor::temporal_zoom (gdouble fpu)
+Editor::temporal_zoom (double fpu)
 {
-	if (!_session) return;
+	if (!_session) {
+		return;
+	}
 
 	framepos_t current_page = current_page_frames();
 	framepos_t current_leftmost = leftmost_frame;
@@ -1362,9 +1380,8 @@ Editor::temporal_zoom (gdouble fpu)
 	double nfpu;
 	double l;
 
-	/* XXX this limit is also in ::set_frames_per_unit() */
-
-	if (frames_per_unit <= 1.0 && fpu <= frames_per_unit) {
+	clamp_frames_per_unit (fpu);
+	if (fpu == frames_per_unit) {
 		return;
 	}