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LibGUI: Animated smooth scroll interpolation

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This commit is contained in:
ForLoveOfCats 2022-03-07 14:19:35 -05:00 • committed by Andreas Kling
parent 86c0961240
commit c204885a94
3 changed files with 75 additions and 7 deletions
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53
Userland/Libraries/LibGUI/Scrollbar.cpp
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@ -12,6 +12,9 @@
#include <LibGfx/Palette.h>
#include <LibGfx/StylePainter.h>
static constexpr int ANIMATION_INTERVAL = 16; // Milliseconds
static constexpr double ANIMATION_TIME = 0.18; // Seconds
REGISTER_WIDGET(GUI, Scrollbar)
namespace GUI {
@ -115,6 +118,39 @@ bool Scrollbar::has_scrubber() const
return max() != min();
}
void Scrollbar::set_value(int value, AllowCallback allow_callback)
{
m_target_value = value;
if (!(m_animated_scrolling_timer.is_null()))
m_animated_scrolling_timer->stop();
AbstractSlider::set_value(value, allow_callback);
}
void Scrollbar::set_target_value(int new_target_value)
{
new_target_value = clamp(new_target_value, min(), max());
// If we are already at or scrolling to the new target then don't touch anything
if (m_target_value == new_target_value)
return;
m_animation_time_elapsed = 0;
m_start_value = value();
m_target_value = new_target_value;
if (m_animated_scrolling_timer.is_null()) {
m_animated_scrolling_timer = add<Core::Timer>();
m_animated_scrolling_timer->set_interval(ANIMATION_INTERVAL);
m_animated_scrolling_timer->on_timeout = [this]() {
m_animation_time_elapsed += (double)ANIMATION_INTERVAL / 1'000; // ms -> sec
update_animated_scroll();
};
}
m_animated_scrolling_timer->start();
}
float Scrollbar::unclamped_scrubber_size() const
{
float pixel_range = length(orientation()) - button_size() * 2;
@ -335,7 +371,7 @@ void Scrollbar::scroll_to_position(const Gfx::IntPoint& click_position)
float x_or_y = ::max(0, click_position.primary_offset_for_orientation(orientation()) - button_width() - button_width() / 2);
float rel_x_or_y = x_or_y / available;
set_value(min() + rel_x_or_y * range_size);
set_target_value(min() + rel_x_or_y * range_size);
}
Scrollbar::Component Scrollbar::component_at_position(const Gfx::IntPoint& position)
@ -391,4 +427,19 @@ void Scrollbar::change_event(Event& event)
return Widget::change_event(event);
}
void Scrollbar::update_animated_scroll()
{
if (value() == m_target_value) {
m_animated_scrolling_timer->stop();
return;
}
double time_percent = m_animation_time_elapsed / ANIMATION_TIME;
double ease_percent = 1.0 - pow(1.0 - time_percent, 5.0); // Ease out quint
double initial_distance = m_target_value - m_start_value;
double new_distance = initial_distance * ease_percent;
int new_value = m_start_value + (int)round(new_distance);
AbstractSlider::set_value(new_value);
}
}