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// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "flutter/shell/platform/linux/fl_scrolling_manager.h"
static constexpr int kMicrosecondsPerMillisecond = 1000;
struct _FlScrollingManager {
GObject parent_instance;
FlScrollingViewDelegate* view_delegate;
gdouble last_x;
gdouble last_y;
gboolean pan_started;
gdouble pan_x;
gdouble pan_y;
gboolean zoom_started;
gboolean rotate_started;
gdouble scale;
gdouble rotation;
};
G_DEFINE_TYPE(FlScrollingManager, fl_scrolling_manager, G_TYPE_OBJECT);
static void fl_scrolling_manager_dispose(GObject* object);
static void fl_scrolling_manager_class_init(FlScrollingManagerClass* klass) {
G_OBJECT_CLASS(klass)->dispose = fl_scrolling_manager_dispose;
}
static void fl_scrolling_manager_init(FlScrollingManager* self) {}
static void fl_scrolling_manager_dispose(GObject* object) {
G_OBJECT_CLASS(fl_scrolling_manager_parent_class)->dispose(object);
}
FlScrollingManager* fl_scrolling_manager_new(
FlScrollingViewDelegate* view_delegate) {
g_return_val_if_fail(FL_IS_SCROLLING_VIEW_DELEGATE(view_delegate), nullptr);
FlScrollingManager* self = FL_SCROLLING_MANAGER(
g_object_new(fl_scrolling_manager_get_type(), nullptr));
self->view_delegate = view_delegate;
g_object_add_weak_pointer(
G_OBJECT(view_delegate),
reinterpret_cast<gpointer*>(&(self->view_delegate)));
self->pan_started = false;
self->zoom_started = false;
self->rotate_started = false;
return self;
}
void fl_scrolling_manager_set_last_mouse_position(FlScrollingManager* self,
gdouble x,
gdouble y) {
self->last_x = x;
self->last_y = y;
}
void fl_scrolling_manager_handle_scroll_event(FlScrollingManager* self,
GdkEventScroll* event,
gint scale_factor) {
gdouble scroll_delta_x = 0.0, scroll_delta_y = 0.0;
if (event->direction == GDK_SCROLL_SMOOTH) {
scroll_delta_x = event->delta_x;
scroll_delta_y = event->delta_y;
} else if (event->direction == GDK_SCROLL_UP) {
scroll_delta_y = -1;
} else if (event->direction == GDK_SCROLL_DOWN) {
scroll_delta_y = 1;
} else if (event->direction == GDK_SCROLL_LEFT) {
scroll_delta_x = -1;
} else if (event->direction == GDK_SCROLL_RIGHT) {
scroll_delta_x = 1;
}
// The multiplier is taken from the Chromium source
// (ui/events/x/events_x_utils.cc).
const int kScrollOffsetMultiplier = 53;
scroll_delta_x *= kScrollOffsetMultiplier * scale_factor;
scroll_delta_y *= kScrollOffsetMultiplier * scale_factor;
if (gdk_device_get_source(gdk_event_get_source_device((GdkEvent*)event)) ==
GDK_SOURCE_TOUCHPAD) {
scroll_delta_x *= -1;
scroll_delta_y *= -1;
if (event->is_stop) {
fl_scrolling_view_delegate_send_pointer_pan_zoom_event(
self->view_delegate, event->time * kMicrosecondsPerMillisecond,
event->x * scale_factor, event->y * scale_factor, kPanZoomEnd,
self->pan_x, self->pan_y, 0, 0);
self->pan_started = FALSE;
} else {
if (!self->pan_started) {
self->pan_x = 0;
self->pan_y = 0;
fl_scrolling_view_delegate_send_pointer_pan_zoom_event(
self->view_delegate, event->time * kMicrosecondsPerMillisecond,
event->x * scale_factor, event->y * scale_factor, kPanZoomStart, 0,
0, 0, 0);
self->pan_started = TRUE;
}
self->pan_x += scroll_delta_x;
self->pan_y += scroll_delta_y;
fl_scrolling_view_delegate_send_pointer_pan_zoom_event(
self->view_delegate, event->time * kMicrosecondsPerMillisecond,
event->x * scale_factor, event->y * scale_factor, kPanZoomUpdate,
self->pan_x, self->pan_y, 1, 0);
}
} else {
self->last_x = event->x * scale_factor;
self->last_y = event->y * scale_factor;
fl_scrolling_view_delegate_send_mouse_pointer_event(
self->view_delegate,
FlutterPointerPhase::kMove /* arbitrary value, phase will be ignored as
this is a discrete scroll event */
,
event->time * kMicrosecondsPerMillisecond, event->x * scale_factor,
event->y * scale_factor, scroll_delta_x, scroll_delta_y, 0);
}
}
void fl_scrolling_manager_handle_rotation_begin(FlScrollingManager* self) {
self->rotate_started = true;
if (!self->zoom_started) {
self->scale = 1;
self->rotation = 0;
fl_scrolling_view_delegate_send_pointer_pan_zoom_event(
self->view_delegate, g_get_real_time(), self->last_x, self->last_y,
kPanZoomStart, 0, 0, 0, 0);
}
}
void fl_scrolling_manager_handle_rotation_update(FlScrollingManager* self,
gdouble rotation) {
self->rotation = rotation;
fl_scrolling_view_delegate_send_pointer_pan_zoom_event(
self->view_delegate, g_get_real_time(), self->last_x, self->last_y,
kPanZoomUpdate, 0, 0, self->scale, self->rotation);
}
void fl_scrolling_manager_handle_rotation_end(FlScrollingManager* self) {
self->rotate_started = false;
if (!self->zoom_started) {
fl_scrolling_view_delegate_send_pointer_pan_zoom_event(
self->view_delegate, g_get_real_time(), self->last_x, self->last_y,
kPanZoomEnd, 0, 0, 0, 0);
}
}
void fl_scrolling_manager_handle_zoom_begin(FlScrollingManager* self) {
self->zoom_started = true;
if (!self->rotate_started) {
self->scale = 1;
self->rotation = 0;
fl_scrolling_view_delegate_send_pointer_pan_zoom_event(
self->view_delegate, g_get_real_time(), self->last_x, self->last_y,
kPanZoomStart, 0, 0, 0, 0);
}
}
void fl_scrolling_manager_handle_zoom_update(FlScrollingManager* self,
gdouble scale) {
self->scale = scale;
fl_scrolling_view_delegate_send_pointer_pan_zoom_event(
self->view_delegate, g_get_real_time(), self->last_x, self->last_y,
kPanZoomUpdate, 0, 0, self->scale, self->rotation);
}
void fl_scrolling_manager_handle_zoom_end(FlScrollingManager* self) {
self->zoom_started = false;
if (!self->rotate_started) {
fl_scrolling_view_delegate_send_pointer_pan_zoom_event(
self->view_delegate, g_get_real_time(), self->last_x, self->last_y,
kPanZoomEnd, 0, 0, 0, 0);
}
}