ladybird/Userland/Libraries/LibGUI/Scrollbar.cpp
2021-10-27 22:05:58 +03:00

369 lines
12 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibCore/Timer.h>
#include <LibGUI/Painter.h>
#include <LibGUI/Scrollbar.h>
#include <LibGfx/CharacterBitmap.h>
#include <LibGfx/Palette.h>
#include <LibGfx/StylePainter.h>
REGISTER_WIDGET(GUI, Scrollbar)
namespace GUI {
static const char* s_up_arrow_bitmap_data = {
" "
" "
" "
" # "
" ### "
" ##### "
" ####### "
" "
" "
};
static const char* s_down_arrow_bitmap_data = {
" "
" "
" "
" ####### "
" ##### "
" ### "
" # "
" "
" "
};
static const char* s_left_arrow_bitmap_data = {
" "
" # "
" ## "
" ### "
" #### "
" ### "
" ## "
" # "
" "
};
static const char* s_right_arrow_bitmap_data = {
" "
" # "
" ## "
" ### "
" #### "
" ### "
" ## "
" # "
" "
};
static Gfx::CharacterBitmap* s_up_arrow_bitmap;
static Gfx::CharacterBitmap* s_down_arrow_bitmap;
static Gfx::CharacterBitmap* s_left_arrow_bitmap;
static Gfx::CharacterBitmap* s_right_arrow_bitmap;
Scrollbar::Scrollbar(Orientation orientation)
: AbstractSlider(orientation)
{
m_automatic_scrolling_timer = add<Core::Timer>();
if (!s_up_arrow_bitmap)
s_up_arrow_bitmap = &Gfx::CharacterBitmap::create_from_ascii(s_up_arrow_bitmap_data, 9, 9).leak_ref();
if (!s_down_arrow_bitmap)
s_down_arrow_bitmap = &Gfx::CharacterBitmap::create_from_ascii(s_down_arrow_bitmap_data, 9, 9).leak_ref();
if (!s_left_arrow_bitmap)
s_left_arrow_bitmap = &Gfx::CharacterBitmap::create_from_ascii(s_left_arrow_bitmap_data, 9, 9).leak_ref();
if (!s_right_arrow_bitmap)
s_right_arrow_bitmap = &Gfx::CharacterBitmap::create_from_ascii(s_right_arrow_bitmap_data, 9, 9).leak_ref();
if (orientation == Orientation::Vertical) {
set_fixed_width(16);
} else {
set_fixed_height(16);
}
m_automatic_scrolling_timer->set_interval(100);
m_automatic_scrolling_timer->on_timeout = [this] {
on_automatic_scrolling_timer_fired();
};
}
Scrollbar::~Scrollbar()
{
}
Gfx::IntRect Scrollbar::decrement_button_rect() const
{
return { 0, 0, button_width(), button_height() };
}
Gfx::IntRect Scrollbar::increment_button_rect() const
{
if (orientation() == Orientation::Vertical)
return { 0, height() - button_height(), button_width(), button_height() };
else
return { width() - button_width(), 0, button_width(), button_height() };
}
int Scrollbar::scrubbable_range_in_pixels() const
{
if (orientation() == Orientation::Vertical)
return height() - button_height() * 2 - visible_scrubber_size();
else
return width() - button_width() * 2 - visible_scrubber_size();
}
bool Scrollbar::has_scrubber() const
{
return max() != min();
}
float Scrollbar::unclamped_scrubber_size() const
{
float pixel_range = length(orientation()) - button_size() * 2;
float value_range = max() - min();
float scrubber_size { 0 };
if (value_range > 0) {
// Scrubber size should be proportional to the visible portion
// (page) in relation to the content (value range + page)
scrubber_size = (page_step() * pixel_range) / (value_range + page_step());
}
return scrubber_size;
}
int Scrollbar::visible_scrubber_size() const
{
return ::max(unclamped_scrubber_size(), button_size());
}
Gfx::IntRect Scrollbar::scrubber_rect() const
{
if (!has_scrubber() || length(orientation()) <= (button_size() * 2) + visible_scrubber_size())
return {};
float x_or_y;
if (value() == min())
x_or_y = button_size();
else if (value() == max())
x_or_y = length(orientation()) - button_size() - visible_scrubber_size();
else {
float range_size = max() - min();
float available = scrubbable_range_in_pixels();
float step = available / range_size;
x_or_y = (button_size() + (step * value()));
}
if (orientation() == Orientation::Vertical)
return { 0, (int)x_or_y, button_width(), visible_scrubber_size() };
else
return { (int)x_or_y, 0, visible_scrubber_size(), button_height() };
}
void Scrollbar::paint_event(PaintEvent& event)
{
Painter painter(*this);
painter.add_clip_rect(event.rect());
Component hovered_component_for_painting = m_hovered_component;
if (!has_scrubber() || (m_pressed_component != Component::None && m_hovered_component != m_pressed_component))
hovered_component_for_painting = Component::None;
painter.fill_rect_with_dither_pattern(rect(), palette().button().lightened(1.3f), palette().button());
bool decrement_pressed = (m_pressed_component == Component::DecrementButton) && (m_pressed_component == m_hovered_component);
bool increment_pressed = (m_pressed_component == Component::IncrementButton) && (m_pressed_component == m_hovered_component);
Gfx::StylePainter::paint_button(painter, decrement_button_rect(), palette(), Gfx::ButtonStyle::ThickCap, decrement_pressed, hovered_component_for_painting == Component::DecrementButton);
Gfx::StylePainter::paint_button(painter, increment_button_rect(), palette(), Gfx::ButtonStyle::ThickCap, increment_pressed, hovered_component_for_painting == Component::IncrementButton);
if (length(orientation()) > default_button_size()) {
auto decrement_location = decrement_button_rect().location().translated(3, 3);
if (decrement_pressed)
decrement_location.translate_by(1, 1);
if (!has_scrubber() || !is_enabled())
painter.draw_bitmap(decrement_location.translated(1, 1), orientation() == Orientation::Vertical ? *s_up_arrow_bitmap : *s_left_arrow_bitmap, palette().threed_highlight());
painter.draw_bitmap(decrement_location, orientation() == Orientation::Vertical ? *s_up_arrow_bitmap : *s_left_arrow_bitmap, (has_scrubber() && is_enabled()) ? palette().button_text() : palette().threed_shadow1());
auto increment_location = increment_button_rect().location().translated(3, 3);
if (increment_pressed)
increment_location.translate_by(1, 1);
if (!has_scrubber() || !is_enabled())
painter.draw_bitmap(increment_location.translated(1, 1), orientation() == Orientation::Vertical ? *s_down_arrow_bitmap : *s_right_arrow_bitmap, palette().threed_highlight());
painter.draw_bitmap(increment_location, orientation() == Orientation::Vertical ? *s_down_arrow_bitmap : *s_right_arrow_bitmap, (has_scrubber() && is_enabled()) ? palette().button_text() : palette().threed_shadow1());
}
if (has_scrubber() && !scrubber_rect().is_null())
Gfx::StylePainter::paint_button(painter, scrubber_rect(), palette(), Gfx::ButtonStyle::ThickCap, false, hovered_component_for_painting == Component::Scrubber || m_pressed_component == Component::Scrubber);
}
void Scrollbar::on_automatic_scrolling_timer_fired()
{
if (m_pressed_component == Component::DecrementButton && component_at_position(m_last_mouse_position) == Component::DecrementButton) {
set_value(value() - step());
return;
}
if (m_pressed_component == Component::IncrementButton && component_at_position(m_last_mouse_position) == Component::IncrementButton) {
set_value(value() + step());
return;
}
if (m_pressed_component == Component::Gutter && component_at_position(m_last_mouse_position) == Component::Gutter) {
scroll_by_page(m_last_mouse_position);
m_hovered_component = component_at_position(m_last_mouse_position);
return;
}
}
void Scrollbar::mousedown_event(MouseEvent& event)
{
if (event.button() != MouseButton::Primary)
return;
if (!has_scrubber())
return;
m_last_mouse_position = event.position();
m_pressed_component = component_at_position(m_last_mouse_position);
if (m_pressed_component == Component::DecrementButton) {
set_automatic_scrolling_active(true, Component::DecrementButton);
update();
return;
}
if (m_pressed_component == Component::IncrementButton) {
set_automatic_scrolling_active(true, Component::IncrementButton);
update();
return;
}
if (event.shift()) {
scroll_to_position(event.position());
m_pressed_component = component_at_position(event.position());
VERIFY(m_pressed_component == Component::Scrubber);
}
if (m_pressed_component == Component::Scrubber) {
m_scrub_start_value = value();
m_scrub_origin = event.position();
update();
return;
}
VERIFY(!event.shift());
VERIFY(m_pressed_component == Component::Gutter);
set_automatic_scrolling_active(true, Component::Gutter);
update();
}
void Scrollbar::mouseup_event(MouseEvent& event)
{
if (event.button() != MouseButton::Primary)
return;
set_automatic_scrolling_active(false, Component::None);
update();
}
void Scrollbar::mousewheel_event(MouseEvent& event)
{
if (!is_scrollable())
return;
set_value(value() + event.wheel_delta() * step());
Widget::mousewheel_event(event);
}
void Scrollbar::set_automatic_scrolling_active(bool active, Component pressed_component)
{
m_pressed_component = pressed_component;
if (m_pressed_component == Component::Gutter)
m_automatic_scrolling_timer->set_interval(200);
else
m_automatic_scrolling_timer->set_interval(100);
if (active) {
on_automatic_scrolling_timer_fired();
m_automatic_scrolling_timer->start();
} else {
m_automatic_scrolling_timer->stop();
}
}
void Scrollbar::scroll_by_page(const Gfx::IntPoint& click_position)
{
float range_size = max() - min();
float available = scrubbable_range_in_pixels();
float rel_scrubber_size = unclamped_scrubber_size() / available;
float page_increment = range_size * rel_scrubber_size;
if (click_position.primary_offset_for_orientation(orientation()) < scrubber_rect().primary_offset_for_orientation(orientation()))
set_value(value() - page_increment);
else
set_value(value() + page_increment);
}
void Scrollbar::scroll_to_position(const Gfx::IntPoint& click_position)
{
float range_size = max() - min();
float available = scrubbable_range_in_pixels();
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);
}
Scrollbar::Component Scrollbar::component_at_position(const Gfx::IntPoint& position)
{
if (scrubber_rect().contains(position))
return Component::Scrubber;
if (decrement_button_rect().contains(position))
return Component::DecrementButton;
if (increment_button_rect().contains(position))
return Component::IncrementButton;
if (rect().contains(position))
return Component::Gutter;
return Component::None;
}
void Scrollbar::mousemove_event(MouseEvent& event)
{
if (!is_scrollable())
return;
m_last_mouse_position = event.position();
auto old_hovered_component = m_hovered_component;
m_hovered_component = component_at_position(m_last_mouse_position);
if (old_hovered_component != m_hovered_component) {
if (is_enabled())
update();
}
if (m_pressed_component != Component::Scrubber)
return;
float delta = orientation() == Orientation::Vertical ? (event.y() - m_scrub_origin.y()) : (event.x() - m_scrub_origin.x());
float scrubbable_range = scrubbable_range_in_pixels();
float value_steps_per_scrubbed_pixel = (max() - min()) / scrubbable_range;
float new_value = m_scrub_start_value + (value_steps_per_scrubbed_pixel * delta);
set_value(new_value);
}
void Scrollbar::leave_event(Core::Event&)
{
if (m_hovered_component != Component::None) {
m_hovered_component = Component::None;
if (is_enabled())
update();
}
}
void Scrollbar::change_event(Event& event)
{
if (event.type() == Event::Type::EnabledChange) {
if (!is_enabled())
set_automatic_scrolling_active(false, Component::None);
}
return Widget::change_event(event);
}
}