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	 7b0adee487
			
		
	
	
		7b0adee487
		
	
	
	
	
		
			
			Having a `Point`, `Rect` or `Size` claim it's `null` is silly. We have `Optional<T>` for that. For `Point`, rename `is_null` to `is_zero` to better reflect what we're testing. For `Rect` and `Size`, `is_null` is removed outright. Also, remove `is_empty` from `Point`. Points can't be empty.
		
			
				
	
	
		
			442 lines
		
	
	
	
		
			16 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			442 lines
		
	
	
	
		
			16 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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|  * Copyright (c) 2022, the SerenityOS developers.
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|  *
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|  * SPDX-License-Identifier: BSD-2-Clause
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|  */
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| 
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| #include <LibCore/Timer.h>
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| #include <LibGUI/Desktop.h>
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| #include <LibGUI/Painter.h>
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| #include <LibGUI/Scrollbar.h>
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| #include <LibGfx/CharacterBitmap.h>
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| #include <LibGfx/Palette.h>
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| #include <LibGfx/StylePainter.h>
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| 
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| static constexpr int ANIMATION_INTERVAL = 16;  // Milliseconds
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| static constexpr double ANIMATION_TIME = 0.18; // Seconds
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| 
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| REGISTER_WIDGET(GUI, Scrollbar)
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| 
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| namespace GUI {
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| 
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| static constexpr AK::Array<Gfx::IntPoint, 3> s_up_arrow_coords = {
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|     Gfx::IntPoint { 4, 2 },
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|     Gfx::IntPoint { 1, 5 },
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|     Gfx::IntPoint { 7, 5 },
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| };
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| 
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| static constexpr AK::Array<Gfx::IntPoint, 3> s_down_arrow_coords = {
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|     Gfx::IntPoint { 1, 3 },
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|     Gfx::IntPoint { 7, 3 },
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|     Gfx::IntPoint { 4, 6 },
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| };
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| 
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| static constexpr AK::Array<Gfx::IntPoint, 3> s_left_arrow_coords = {
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|     Gfx::IntPoint { 5, 1 },
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|     Gfx::IntPoint { 2, 4 },
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|     Gfx::IntPoint { 5, 7 },
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| };
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| 
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| static constexpr AK::Array<Gfx::IntPoint, 3> s_right_arrow_coords = {
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|     Gfx::IntPoint { 3, 1 },
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|     Gfx::IntPoint { 6, 4 },
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|     Gfx::IntPoint { 3, 7 },
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| };
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| 
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| Scrollbar::Scrollbar(Orientation orientation)
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|     : AbstractSlider(orientation)
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| {
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|     m_automatic_scrolling_timer = add<Core::Timer>();
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| 
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|     set_preferred_size({ SpecialDimension::Fit });
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| 
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|     m_automatic_scrolling_timer->set_interval(100);
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|     m_automatic_scrolling_timer->on_timeout = [this] {
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|         automatic_scrolling_timer_did_fire();
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|     };
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| }
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| 
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| Gfx::IntRect Scrollbar::decrement_button_rect() const
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| {
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|     return { 0, 0, button_width(), button_height() };
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| }
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| 
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| Gfx::IntRect Scrollbar::increment_button_rect() const
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| {
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|     if (orientation() == Orientation::Vertical)
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|         return { 0, height() - button_height(), button_width(), button_height() };
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|     else
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|         return { width() - button_width(), 0, button_width(), button_height() };
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| }
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| 
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| int Scrollbar::scrubbable_range_in_pixels() const
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| {
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|     if (orientation() == Orientation::Vertical)
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|         return height() - button_height() * 2 - visible_scrubber_size();
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|     else
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|         return width() - button_width() * 2 - visible_scrubber_size();
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| }
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| 
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| bool Scrollbar::has_scrubber() const
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| {
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|     return max() != min();
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| }
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| 
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| void Scrollbar::set_scroll_animation(Animation scroll_animation)
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| {
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|     m_scroll_animation = scroll_animation;
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| }
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| 
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| void Scrollbar::set_value(int value, AllowCallback allow_callback, DoClamp do_clamp)
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| {
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|     m_target_value = value;
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|     if (!(m_animated_scrolling_timer.is_null()))
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|         m_animated_scrolling_timer->stop();
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| 
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|     AbstractSlider::set_value(value, allow_callback, do_clamp);
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| }
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| 
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| void Scrollbar::set_target_value(int new_target_value)
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| {
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|     new_target_value = clamp(new_target_value, min(), max());
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| 
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|     // If we are already at or scrolling to the new target then don't touch anything
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|     if (m_target_value == new_target_value)
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|         return;
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| 
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|     if (m_scroll_animation == Animation::CoarseScroll || !Desktop::the().system_effects().smooth_scrolling())
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|         return set_value(new_target_value);
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| 
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|     m_animation_time_elapsed = 0;
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|     m_start_value = value();
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|     m_target_value = new_target_value;
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| 
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|     if (m_animated_scrolling_timer.is_null()) {
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|         m_animated_scrolling_timer = add<Core::Timer>();
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|         m_animated_scrolling_timer->set_interval(ANIMATION_INTERVAL);
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|         m_animated_scrolling_timer->on_timeout = [this]() {
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|             m_animation_time_elapsed += (double)ANIMATION_INTERVAL / 1'000; // ms -> sec
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|             update_animated_scroll();
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|         };
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|     }
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| 
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|     m_animated_scrolling_timer->start();
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| }
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| 
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| float Scrollbar::unclamped_scrubber_size() const
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| {
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|     float pixel_range = length(orientation()) - button_size() * 2;
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|     float value_range = max() - min();
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| 
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|     float scrubber_size { 0 };
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|     if (value_range > 0) {
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|         // Scrubber size should be proportional to the visible portion
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|         // (page) in relation to the content (value range + page)
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|         scrubber_size = (page_step() * pixel_range) / (value_range + page_step());
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|     }
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|     return scrubber_size;
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| }
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| 
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| int Scrollbar::visible_scrubber_size() const
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| {
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|     return ::max(unclamped_scrubber_size(), button_size());
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| }
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| 
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| Gfx::IntRect Scrollbar::scrubber_rect() const
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| {
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|     if (!has_scrubber() || length(orientation()) <= (button_size() * 2) + visible_scrubber_size())
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|         return {};
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|     float x_or_y;
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|     if (value() == min())
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|         x_or_y = button_size();
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|     else if (value() == max())
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|         x_or_y = length(orientation()) - button_size() - visible_scrubber_size();
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|     else {
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|         float range_size = max() - min();
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|         float available = scrubbable_range_in_pixels();
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|         float step = available / range_size;
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|         x_or_y = (button_size() + (step * value()));
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|     }
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| 
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|     if (orientation() == Orientation::Vertical)
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|         return { 0, (int)x_or_y, button_width(), visible_scrubber_size() };
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|     else
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|         return { (int)x_or_y, 0, visible_scrubber_size(), button_height() };
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| }
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| 
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| void Scrollbar::paint_event(PaintEvent& event)
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| {
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|     Painter painter(*this);
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|     painter.add_clip_rect(event.rect());
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| 
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|     Component hovered_component_for_painting = m_hovered_component;
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|     if (!has_scrubber() || (m_pressed_component != Component::None && m_hovered_component != m_pressed_component))
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|         hovered_component_for_painting = Component::None;
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| 
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|     painter.fill_rect_with_dither_pattern(rect(), palette().button().lightened(1.3f), palette().button());
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|     if (m_gutter_click_state != GutterClickState::NotPressed && has_scrubber() && !scrubber_rect().is_empty() && hovered_component_for_painting == Component::Gutter) {
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|         Gfx::IntRect rect_to_fill = rect();
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|         if (orientation() == Orientation::Vertical) {
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|             if (m_gutter_click_state == GutterClickState::BeforeScrubber) {
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|                 rect_to_fill.set_top(decrement_button_rect().bottom());
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|                 rect_to_fill.set_bottom(scrubber_rect().top());
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|             } else {
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|                 VERIFY(m_gutter_click_state == GutterClickState::AfterScrubber);
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|                 rect_to_fill.set_top(scrubber_rect().bottom());
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|                 rect_to_fill.set_bottom(increment_button_rect().top());
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|             }
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|         } else {
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|             if (m_gutter_click_state == GutterClickState::BeforeScrubber) {
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|                 rect_to_fill.set_left(decrement_button_rect().right());
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|                 rect_to_fill.set_right(scrubber_rect().left());
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|             } else {
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|                 VERIFY(m_gutter_click_state == GutterClickState::AfterScrubber);
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|                 rect_to_fill.set_left(scrubber_rect().right());
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|                 rect_to_fill.set_right(increment_button_rect().left());
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|             }
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|         }
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|         painter.fill_rect_with_dither_pattern(rect_to_fill, palette().button(), palette().button().lightened(0.77f));
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|     }
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| 
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|     bool decrement_pressed = (m_pressed_component == Component::DecrementButton) && (m_pressed_component == m_hovered_component) && !is_min();
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|     bool increment_pressed = (m_pressed_component == Component::IncrementButton) && (m_pressed_component == m_hovered_component) && !is_max();
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| 
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|     Gfx::StylePainter::paint_button(painter, decrement_button_rect(), palette(), Gfx::ButtonStyle::ThickCap, decrement_pressed, hovered_component_for_painting == Component::DecrementButton && !is_min());
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|     Gfx::StylePainter::paint_button(painter, increment_button_rect(), palette(), Gfx::ButtonStyle::ThickCap, increment_pressed, hovered_component_for_painting == Component::IncrementButton && !is_max());
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| 
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|     if (length(orientation()) >= default_button_size() * 2) {
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|         auto decrement_location = decrement_button_rect().location().translated(3, 3);
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|         if (decrement_pressed)
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|             decrement_location.translate_by(1, 1);
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|         if (!has_scrubber() || !is_enabled())
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|             painter.draw_triangle(decrement_location + Gfx::IntPoint { 1, 1 }, orientation() == Orientation::Vertical ? s_up_arrow_coords : s_left_arrow_coords, palette().threed_highlight());
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|         painter.draw_triangle(decrement_location, orientation() == Orientation::Vertical ? s_up_arrow_coords : s_left_arrow_coords, (has_scrubber() && is_enabled() && !is_min()) ? palette().button_text() : palette().threed_shadow1());
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| 
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|         auto increment_location = increment_button_rect().location().translated(3, 3);
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|         if (increment_pressed)
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|             increment_location.translate_by(1, 1);
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|         if (!has_scrubber() || !is_enabled())
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|             painter.draw_triangle(increment_location + Gfx::IntPoint { 1, 1 }, orientation() == Orientation::Vertical ? s_down_arrow_coords : s_right_arrow_coords, palette().threed_highlight());
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|         painter.draw_triangle(increment_location, orientation() == Orientation::Vertical ? s_down_arrow_coords : s_right_arrow_coords, (has_scrubber() && is_enabled() && !is_max()) ? palette().button_text() : palette().threed_shadow1());
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|     }
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| 
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|     if (has_scrubber() && !scrubber_rect().is_empty())
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|         Gfx::StylePainter::paint_button(painter, scrubber_rect(), palette(), Gfx::ButtonStyle::ThickCap, false, hovered_component_for_painting == Component::Scrubber || m_pressed_component == Component::Scrubber);
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| }
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| 
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| void Scrollbar::automatic_scrolling_timer_did_fire()
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| {
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|     if (m_pressed_component == Component::DecrementButton && component_at_position(m_last_mouse_position) == Component::DecrementButton) {
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|         decrease_slider_by_steps(1);
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|         return;
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|     }
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|     if (m_pressed_component == Component::IncrementButton && component_at_position(m_last_mouse_position) == Component::IncrementButton) {
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|         increase_slider_by_steps(1);
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|         return;
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|     }
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|     if (m_pressed_component == Component::Gutter && component_at_position(m_last_mouse_position) == Component::Gutter) {
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|         scroll_by_page(m_last_mouse_position);
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|         if (m_hovered_component != component_at_position(m_last_mouse_position)) {
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|             m_hovered_component = component_at_position(m_last_mouse_position);
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|             if (m_hovered_component != Component::Gutter)
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|                 m_gutter_click_state = GutterClickState::NotPressed;
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|             update();
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|         }
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|         return;
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|     }
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|     if (m_gutter_click_state != GutterClickState::NotPressed) {
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|         m_gutter_click_state = GutterClickState::NotPressed;
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|         update();
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|         return;
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|     }
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| }
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| 
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| void Scrollbar::mousedown_event(MouseEvent& event)
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| {
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|     if (event.button() != MouseButton::Primary)
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|         return;
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|     if (!has_scrubber())
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|         return;
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| 
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|     m_last_mouse_position = event.position();
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|     m_pressed_component = component_at_position(m_last_mouse_position);
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| 
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|     if (m_pressed_component == Component::DecrementButton) {
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|         if (is_min())
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|             return;
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|         set_automatic_scrolling_timer_active(true, Component::DecrementButton);
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|         update();
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|         return;
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|     }
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|     if (m_pressed_component == Component::IncrementButton) {
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|         if (is_max())
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|             return;
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|         set_automatic_scrolling_timer_active(true, Component::IncrementButton);
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|         update();
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|         return;
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|     }
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| 
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|     if (event.shift()) {
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|         scroll_to_position(event.position());
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|         m_pressed_component = component_at_position(event.position());
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|         return;
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|     }
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|     if (m_pressed_component == Component::Scrubber) {
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|         m_scrub_start_value = value();
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|         m_scrub_origin = event.position();
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|         update();
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|         return;
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|     }
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|     VERIFY(!event.shift());
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| 
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|     VERIFY(m_pressed_component == Component::Gutter);
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|     set_automatic_scrolling_timer_active(true, Component::Gutter);
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|     update();
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| }
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| 
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| void Scrollbar::mouseup_event(MouseEvent& event)
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| {
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|     if (event.button() != MouseButton::Primary)
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|         return;
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|     set_automatic_scrolling_timer_active(false, Component::None);
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|     update();
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| }
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| 
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| void Scrollbar::mousewheel_event(MouseEvent& event)
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| {
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|     if (!is_scrollable())
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|         return;
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|     increase_slider_by_steps(event.wheel_delta_y());
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|     Widget::mousewheel_event(event);
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| }
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| 
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| void Scrollbar::set_automatic_scrolling_timer_active(bool active, Component pressed_component)
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| {
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|     m_pressed_component = pressed_component;
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|     if (m_pressed_component == Component::Gutter)
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|         m_automatic_scrolling_timer->set_interval(200);
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|     else
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|         m_automatic_scrolling_timer->set_interval(100);
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| 
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|     if (active) {
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|         automatic_scrolling_timer_did_fire();
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|         m_automatic_scrolling_timer->start();
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|     } else {
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|         m_automatic_scrolling_timer->stop();
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|         m_gutter_click_state = GutterClickState::NotPressed;
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|     }
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| }
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| 
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| void Scrollbar::scroll_by_page(Gfx::IntPoint click_position)
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| {
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|     float range_size = max() - min();
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|     float available = scrubbable_range_in_pixels();
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|     float rel_scrubber_size = unclamped_scrubber_size() / available;
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|     float page_increment = range_size * rel_scrubber_size;
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| 
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|     if (click_position.primary_offset_for_orientation(orientation()) < scrubber_rect().primary_offset_for_orientation(orientation())) {
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|         m_gutter_click_state = GutterClickState::BeforeScrubber;
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|         decrease_slider_by(page_increment);
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|     } else {
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|         m_gutter_click_state = GutterClickState::AfterScrubber;
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|         increase_slider_by(page_increment);
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|     }
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| }
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| 
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| void Scrollbar::scroll_to_position(Gfx::IntPoint click_position)
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| {
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|     float range_size = max() - min();
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|     float available = scrubbable_range_in_pixels();
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| 
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|     float x_or_y = ::max(0, click_position.primary_offset_for_orientation(orientation()) - button_width() - button_width() / 2);
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|     float rel_x_or_y = x_or_y / available;
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|     set_target_value(min() + rel_x_or_y * range_size);
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| }
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| 
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| Scrollbar::Component Scrollbar::component_at_position(Gfx::IntPoint position)
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| {
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|     if (scrubber_rect().contains(position))
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|         return Component::Scrubber;
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|     if (decrement_button_rect().contains(position))
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|         return Component::DecrementButton;
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|     if (increment_button_rect().contains(position))
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|         return Component::IncrementButton;
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|     if (rect().contains(position))
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|         return Component::Gutter;
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|     return Component::None;
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| }
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| 
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| void Scrollbar::mousemove_event(MouseEvent& event)
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| {
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|     if (!is_scrollable())
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|         return;
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| 
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|     m_last_mouse_position = event.position();
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| 
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|     auto old_hovered_component = m_hovered_component;
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|     m_hovered_component = component_at_position(m_last_mouse_position);
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|     if (old_hovered_component != m_hovered_component) {
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|         if (is_enabled())
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|             update();
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|     }
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|     if (m_pressed_component != Component::Scrubber)
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|         return;
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|     float delta = orientation() == Orientation::Vertical ? (event.y() - m_scrub_origin.y()) : (event.x() - m_scrub_origin.x());
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|     float scrubbable_range = scrubbable_range_in_pixels();
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|     float value_steps_per_scrubbed_pixel = (max() - min()) / scrubbable_range;
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|     float new_value = m_scrub_start_value + (value_steps_per_scrubbed_pixel * delta);
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|     set_value(new_value);
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| }
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| 
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| void Scrollbar::leave_event(Core::Event&)
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| {
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|     if (m_hovered_component != Component::None) {
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|         m_hovered_component = Component::None;
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|         if (is_enabled())
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|             update();
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|     }
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| }
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| 
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| void Scrollbar::change_event(Event& event)
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| {
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|     if (event.type() == Event::Type::EnabledChange) {
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|         if (!is_enabled())
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|             set_automatic_scrolling_timer_active(false, Component::None);
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|     }
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|     return Widget::change_event(event);
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| }
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| 
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| void Scrollbar::update_animated_scroll()
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| {
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|     if (value() == m_target_value) {
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|         m_animated_scrolling_timer->stop();
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|         return;
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|     }
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| 
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|     double time_percent = m_animation_time_elapsed / ANIMATION_TIME;
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|     double ease_percent = 1.0 - pow(1.0 - time_percent, 5.0); // Ease out quint
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|     double initial_distance = m_target_value - m_start_value;
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|     double new_distance = initial_distance * ease_percent;
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|     int new_value = m_start_value + (int)round(new_distance);
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|     AbstractSlider::set_value(new_value);
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| }
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| 
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| Optional<UISize> Scrollbar::calculated_min_size() const
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| {
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|     auto scrubber_and_gutter = default_button_size() + 1;
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|     if (orientation() == Gfx::Orientation::Vertical)
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|         return { { default_button_size(), 2 * default_button_size() + scrubber_and_gutter } };
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|     else
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|         return { { 2 * default_button_size() + scrubber_and_gutter, default_button_size() } };
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| }
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| 
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| Optional<UISize> Scrollbar::calculated_preferred_size() const
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| {
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|     if (orientation() == Gfx::Orientation::Vertical)
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|         return { { SpecialDimension::Shrink, SpecialDimension::Grow } };
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|     else
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|         return { { SpecialDimension::Grow, SpecialDimension::Shrink } };
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| }
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| 
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| }
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