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Add PanAxis mode that automatically pins scroll based on initial movement

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This code is inspired by the implementation of the same feature for the
Mx toolkit's MxKineticScrollView. See commit 4d08771.

https://bugzilla.gnome.org/show_bug.cgi?id=707982
This commit is contained in:
Gustavo Noronha Silva 2013-09-11 12:33:57 -03:00 committed by Gustavo Noronha Silva
parent 2105055a34
commit 0c75e17814
5 changed files with 167 additions and 23 deletions
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6
clutter/clutter-enums.h
View File

@ -1018,6 +1018,8 @@ typedef enum { /*< prefix=CLUTTER_SWIPE_DIRECTION >*/
* @CLUTTER_PAN_AXIS_NONE: No constraint
* @CLUTTER_PAN_X_AXIS: Set a constraint on the X axis
* @CLUTTER_PAN_Y_AXIS: Set a constraint on the Y axis
* @CLUTTER_PAN_AXIS_AUTO: Constrain panning automatically based on initial
* movement (available since 1.24)
*
* The axis of the constraint that should be applied on the
* panning action
@ -1028,7 +1030,9 @@ typedef enum { /*< prefix=CLUTTER_PAN >*/
CLUTTER_PAN_AXIS_NONE = 0,
CLUTTER_PAN_X_AXIS,
CLUTTER_PAN_Y_AXIS
CLUTTER_PAN_Y_AXIS,
CLUTTER_PAN_AXIS_AUTO
} ClutterPanAxis;

120
clutter/clutter-pan-action.c
View File

@ -5,7 +5,7 @@
*
* Copyright (C) 2010 Intel Corporation.
* Copyright (C) 2011 Robert Bosch Car Multimedia GmbH.
* Copyright (C) 2012 Collabora Ltd.
* Copyright (C) 2012, 2014 Collabora Ltd.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
@ -80,6 +80,14 @@ typedef enum
PAN_STATE_INTERPOLATING
} PanState;
typedef enum
{
SCROLL_PINNED_UNKNOWN,
SCROLL_PINNED_NONE,
SCROLL_PINNED_HORIZONTAL,
SCROLL_PINNED_VERTICAL
} PinState;
struct _ClutterPanActionPrivate
{
ClutterPanAxis pan_axis;
@ -102,6 +110,8 @@ struct _ClutterPanActionPrivate
gfloat release_y;
guint should_interpolate : 1;
PinState pin_state;
};
enum
@ -135,7 +145,34 @@ emit_pan (ClutterPanAction *self,
ClutterActor *actor,
gboolean is_interpolated)
{
ClutterPanActionPrivate *priv = self->priv;
gboolean retval;
if (priv->pin_state == SCROLL_PINNED_UNKNOWN)
{
priv->pin_state = SCROLL_PINNED_NONE;
if (priv->pan_axis == CLUTTER_PAN_AXIS_AUTO)
{
gfloat delta_x;
gfloat delta_y;
gfloat scroll_threshold = G_PI_4/2;
gfloat drag_angle;
clutter_gesture_action_get_motion_delta (CLUTTER_GESTURE_ACTION (self), 0, &delta_x, &delta_y);
if (delta_x != 0.0f)
drag_angle = atanf (delta_y / delta_x);
else
drag_angle = G_PI_2;
if ((drag_angle > -scroll_threshold) && (drag_angle < scroll_threshold))
priv->pin_state = SCROLL_PINNED_HORIZONTAL;
else if ((drag_angle > (G_PI_2 - scroll_threshold)) ||
(drag_angle < -(G_PI_2 - scroll_threshold)))
priv->pin_state = SCROLL_PINNED_VERTICAL;
}
}
g_signal_emit (self, pan_signals[PAN], 0, actor, is_interpolated, &retval);
}
@ -207,6 +244,7 @@ gesture_begin (ClutterGestureAction *gesture,
ClutterPanAction *self = CLUTTER_PAN_ACTION (gesture);
ClutterPanActionPrivate *priv = self->priv;
priv->pin_state = SCROLL_PINNED_UNKNOWN;
priv->state = PAN_STATE_PANNING;
priv->interpolated_x = priv->interpolated_y = 0.0f;
priv->dx = priv->dy = 0.0f;
@ -297,25 +335,10 @@ clutter_pan_action_real_pan (ClutterPanAction *self,
ClutterActor *actor,
gboolean is_interpolated)
{
ClutterPanActionPrivate *priv = self->priv;
gfloat dx, dy;
ClutterMatrix transform;
clutter_pan_action_get_motion_delta (self, 0, &dx, &dy);
switch (priv->pan_axis)
{
case CLUTTER_PAN_AXIS_NONE:
break;
case CLUTTER_PAN_X_AXIS:
dy = 0.0f;
break;
case CLUTTER_PAN_Y_AXIS:
dx = 0.0f;
break;
}
clutter_pan_action_get_constrained_motion_delta (self, 0, &dx, &dy);
clutter_actor_get_child_transform (actor, &transform);
cogl_matrix_translate (&transform, dx, dy, 0.0f);
@ -605,7 +628,7 @@ clutter_pan_action_set_pan_axis (ClutterPanAction *self,
g_return_if_fail (CLUTTER_IS_PAN_ACTION (self));
g_return_if_fail (axis >= CLUTTER_PAN_AXIS_NONE &&
axis <= CLUTTER_PAN_Y_AXIS);
axis <= CLUTTER_PAN_AXIS_AUTO);
priv = self->priv;
@ -831,6 +854,67 @@ clutter_pan_action_get_interpolated_delta (ClutterPanAction *self,
return sqrt ((priv->dx * priv->dx) + (priv->dy * priv->dy));
}
/**
* clutter_pan_action_get_constrained_motion_delta:
* @self: A #ClutterPanAction
* @point: the touch point index, with 0 being the first touch
* point received by the action
* @delta_x: (out) (optional): return location for the X delta
* @delta_y: (out) (optional): return location for the Y delta
*
* Retrieves the delta, in stage space, dependent on the current state
* of the #ClutterPanAction, and respecting the constraint specified by the
* #ClutterPanAction:pan-axis property.
*
* Return value: the distance since last motion event
*
* Since: 1.24
*/
gfloat
clutter_pan_action_get_constrained_motion_delta (ClutterPanAction *self,
guint point,
gfloat *out_delta_x,
gfloat *out_delta_y)
{
ClutterPanActionPrivate *priv;
gfloat delta_x = 0.f, delta_y = 0.f, distance;
g_return_val_if_fail (CLUTTER_IS_PAN_ACTION (self), 0.0f);
priv = self->priv;
distance = clutter_pan_action_get_motion_delta (self, point, &delta_x, &delta_y);
switch (priv->pan_axis)
{
case CLUTTER_PAN_AXIS_NONE:
break;
case CLUTTER_PAN_AXIS_AUTO:
if (priv->pin_state == SCROLL_PINNED_VERTICAL)
delta_x = 0.0f;
else if (priv->pin_state == SCROLL_PINNED_HORIZONTAL)
delta_y = 0.0f;
break;
case CLUTTER_PAN_X_AXIS:
delta_y = 0.0f;
break;
case CLUTTER_PAN_Y_AXIS:
delta_x = 0.0f;
break;
}
if (out_delta_x)
*out_delta_x = delta_x;
if (out_delta_y)
*out_delta_y = delta_y;
return distance;
}
/**
* clutter_pan_action_get_motion_delta:
* @self: A #ClutterPanAction

5
clutter/clutter-pan-action.h
View File

@ -142,6 +142,11 @@ void clutter_pan_action_get_motion_coords (ClutterPanAction *s
guint point,
gfloat *motion_x,
gfloat *motion_y);
CLUTTER_AVAILABLE_IN_1_24
gfloat clutter_pan_action_get_constrained_motion_delta (ClutterPanAction *self,
guint point,
gfloat *delta_x,
gfloat *delta_y);
G_END_DECLS
#endif /* __CLUTTER_PAN_ACTION_H__ */

1
doc/reference/clutter-sections.txt
View File

@ -3566,6 +3566,7 @@ clutter_pan_action_get_interpolated_coords
clutter_pan_action_get_interpolated_delta
clutter_pan_action_get_motion_coords
clutter_pan_action_get_motion_delta
clutter_pan_action_get_constrained_motion_delta
<SUBSECTION Standard>
CLUTTER_IS_PAN_ACTION
CLUTTER_IS_PAN_ACTION_CLASS

58
examples/pan-action.c
View File

@ -83,7 +83,7 @@ create_scroll_actor (ClutterActor *stage)
pan_action = clutter_pan_action_new ();
clutter_pan_action_set_interpolate (CLUTTER_PAN_ACTION (pan_action), TRUE);
g_signal_connect (pan_action, "pan", G_CALLBACK (on_pan), NULL);
clutter_actor_add_action (scroll, pan_action);
clutter_actor_add_action_with_name (scroll, "pan", pan_action);
clutter_actor_set_reactive (scroll, TRUE);
@ -113,10 +113,45 @@ on_key_press (ClutterActor *stage,
return CLUTTER_EVENT_STOP;
}
static gboolean
label_clicked_cb (ClutterText *label, ClutterEvent *event, ClutterActor *scroll)
{
ClutterPanAction *action = CLUTTER_PAN_ACTION (clutter_actor_get_action (scroll, "pan"));
const gchar *label_text = clutter_text_get_text (label);
if (g_str_equal (label_text, "X AXIS"))
clutter_pan_action_set_pan_axis (action, CLUTTER_PAN_X_AXIS);
else if (g_str_equal (label_text, "Y AXIS"))
clutter_pan_action_set_pan_axis (action, CLUTTER_PAN_Y_AXIS);
else if (g_str_equal (label_text, "AUTO"))
clutter_pan_action_set_pan_axis (action, CLUTTER_PAN_AXIS_AUTO);
else
clutter_pan_action_set_pan_axis (action, CLUTTER_PAN_AXIS_NONE);
return TRUE;
}
static void
add_label (const gchar *text, ClutterActor *box, ClutterActor *scroll)
{
ClutterActor *label;
label = clutter_text_new_with_text (NULL, text);
clutter_actor_set_reactive (label, TRUE);
clutter_actor_set_x_align (label, CLUTTER_ACTOR_ALIGN_START);
clutter_actor_set_x_expand (label, TRUE);
clutter_actor_add_child (box, label);
g_signal_connect (label, "button-release-event",
G_CALLBACK (label_clicked_cb), scroll);
}
int
main (int argc, char *argv[])
{
ClutterActor *stage, *scroll, *info;
ClutterActor *stage, *scroll, *box, *info;
ClutterLayoutManager *layout;
if (clutter_init (&argc, &argv) != CLUTTER_INIT_SUCCESS)
return EXIT_FAILURE;
@ -129,9 +164,24 @@ main (int argc, char *argv[])
scroll = create_scroll_actor (stage);
clutter_actor_add_child (stage, scroll);
box = clutter_actor_new ();
clutter_actor_add_child (stage, box);
clutter_actor_set_position (box, 12, 12);
layout = clutter_box_layout_new ();
clutter_box_layout_set_orientation (CLUTTER_BOX_LAYOUT (layout), CLUTTER_ORIENTATION_VERTICAL);
clutter_actor_set_layout_manager (box, layout);
info = clutter_text_new_with_text (NULL, "Press <space> to reset the image position.");
clutter_actor_add_child (stage, info);
clutter_actor_set_position (info, 12, 12);
clutter_actor_add_child (box, info);
info = clutter_text_new_with_text (NULL, "Click labels below to change AXIS pinning.");
clutter_actor_add_child (box, info);
add_label ("NONE", box, scroll);
add_label ("X AXIS", box, scroll);
add_label ("Y AXIS", box, scroll);
add_label ("AUTO", box, scroll);
g_signal_connect (stage, "destroy", G_CALLBACK (clutter_main_quit), NULL);
g_signal_connect (stage, "key-press-event", G_CALLBACK (on_key_press), scroll);