LibGUI: Support dragging the GScrollBar scrubber.

This was pleasantly easy to implement with the global mouse tracking. :^)
This commit is contained in:
Andreas Kling 2019-02-10 06:51:01 +01:00
parent 6b8af2f33a
commit 9ea2131adf
Notes: sideshowbarker 2024-07-19 15:48:42 +09:00
2 changed files with 48 additions and 9 deletions

View File

@ -55,23 +55,28 @@ Rect GScrollBar::down_button_rect() const
return { 0, height() - button_size(), button_size(), button_size() };
}
Rect GScrollBar::pgup_rect() const
Rect GScrollBar::upper_gutter_rect() const
{
return { 0, button_size(), button_size(), scrubber_rect().top() - button_size() };
}
Rect GScrollBar::pgdn_rect() const
Rect GScrollBar::lower_gutter_rect() const
{
auto scrubber_rect = this->scrubber_rect();
return { 0, scrubber_rect.bottom(), button_size(), height() - button_size() - scrubber_rect.bottom() };
}
int GScrollBar::scrubbable_range_in_pixels() const
{
return height() - button_size() * 3;
}
Rect GScrollBar::scrubber_rect() const
{
int range_size = m_max - m_min;
if (range_size == 0)
return { 0, button_size(), button_size(), height() - button_size() * 2 };
float available_y = height() - button_size() * 3;
float available_y = scrubbable_range_in_pixels();
float y_step = available_y / range_size;
float y = button_size() + (y_step * m_value);
return { 0, (int)y, button_size(), button_size() };
@ -115,7 +120,7 @@ void GScrollBar::paint_event(GPaintEvent&)
Painter painter(*this);
painter.fill_rect(rect(), Color::MidGray);
painter.fill_rect(rect(), Color(164, 164, 164));
painter.draw_rect(up_button_rect(), Color::DarkGray, true);
painter.fill_rect_with_gradient(up_button_rect().shrunken(2, 2), Color::LightGray, Color::White);
@ -141,12 +146,40 @@ void GScrollBar::mousedown_event(GMouseEvent& event)
set_value(value() + m_step);
return;
}
if (pgup_rect().contains(event.position())) {
if (upper_gutter_rect().contains(event.position())) {
set_value(value() - m_big_step);
return;
}
if (pgdn_rect().contains(event.position())) {
if (lower_gutter_rect().contains(event.position())) {
set_value(value() + m_big_step);
return;
}
if (scrubber_rect().contains(event.position())) {
m_scrubbing = true;
m_scrub_start_value = value();
m_scrub_origin = event.position();
set_global_cursor_tracking(true);
return;
}
}
void GScrollBar::mouseup_event(GMouseEvent& event)
{
if (event.button() != GMouseButton::Left)
return;
if (!m_scrubbing)
return;
m_scrubbing = false;
set_global_cursor_tracking(false);
}
void GScrollBar::mousemove_event(GMouseEvent& event)
{
if (!m_scrubbing)
return;
float delta = event.y() - m_scrub_origin.y();
float scrubbable_range = scrubbable_range_in_pixels();
float value_steps_per_scrubbed_pixel = (m_max - m_min) / scrubbable_range;
float new_value = m_scrub_start_value + (value_steps_per_scrubbed_pixel * delta);
set_value(new_value);
}

View File

@ -24,19 +24,25 @@ public:
private:
virtual void paint_event(GPaintEvent&) override;
virtual void mousedown_event(GMouseEvent&) override;
virtual void mouseup_event(GMouseEvent&) override;
virtual void mousemove_event(GMouseEvent&) override;
virtual const char* class_name() const override { return "GScrollBar"; }
int button_size() const { return 16; }
Rect up_button_rect() const;
Rect down_button_rect() const;
Rect pgup_rect() const;
Rect pgdn_rect() const;
Rect upper_gutter_rect() const;
Rect lower_gutter_rect() const;
Rect scrubber_rect() const;
int scrubbable_range_in_pixels() const;
int m_min { 0 };
int m_max { 0 };
int m_value { 0 };
int m_step { 1 };
int m_big_step { 5 };
};
bool m_scrubbing { false };
int m_scrub_start_value { 0 };
Point m_scrub_origin;
};