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Mandelbrot: Extract zoom() method

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This commit is contained in:
Nico Weber 2021-08-14 12:32:16 -04:00 • committed by Gunnar Beutner
parent fbdf17ae68
commit ad7bfe017f
1 changed files with 34 additions and 23 deletions
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57
Userland/Demos/Mandelbrot/Mandelbrot.cpp
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@ -209,6 +209,12 @@ class Mandelbrot : public GUI::Frame {
void export_image(String const& export_path);
enum class Zoom {
In,
Out,
};
void zoom(Zoom in_out, const Gfx::IntPoint& center);
private:
virtual void paint_event(GUI::PaintEvent&) override;
virtual void mousedown_event(GUI::MouseEvent& event) override;
@ -227,6 +233,33 @@ private:
MandelbrotSet m_set;
};
void Mandelbrot::zoom(Zoom in_out, const Gfx::IntPoint& center)
{
static constexpr double zoom_in_multiplier = 0.8;
static constexpr double zoom_out_multiplier = 1.25;
bool zooming_in = in_out == Zoom::In;
double multiplier = zooming_in ? zoom_in_multiplier : zoom_out_multiplier;
auto relative_rect = this->relative_rect();
Gfx::IntRect zoomed_rect = relative_rect;
zoomed_rect.set_width(zoomed_rect.width() * multiplier);
zoomed_rect.set_height(zoomed_rect.height() * multiplier);
auto leftover_width = abs(relative_rect.width() - zoomed_rect.width());
auto leftover_height = abs(relative_rect.height() - zoomed_rect.height());
double cursor_x_percentage = static_cast<double>(center.x()) / relative_rect.width();
double cursor_y_percentage = static_cast<double>(center.y()) / relative_rect.height();
zoomed_rect.set_x((zooming_in ? 1 : -1) * leftover_width * cursor_x_percentage);
zoomed_rect.set_y((zooming_in ? 1 : -1) * leftover_height * cursor_y_percentage);
m_set.zoom(zoomed_rect);
update();
}
void Mandelbrot::paint_event(GUI::PaintEvent& event)
{
Frame::paint_event(event);
@ -306,29 +339,7 @@ void Mandelbrot::mouseup_event(GUI::MouseEvent& event)
void Mandelbrot::mousewheel_event(GUI::MouseEvent& event)
{
static constexpr double zoom_in_multiplier = 0.8;
static constexpr double zoom_out_multiplier = 1.25;
bool zooming_in = event.wheel_delta() < 0;
double multiplier = zooming_in ? zoom_in_multiplier : zoom_out_multiplier;
auto relative_rect = this->relative_rect();
Gfx::IntRect zoomed_rect = relative_rect;
zoomed_rect.set_width(zoomed_rect.width() * multiplier);
zoomed_rect.set_height(zoomed_rect.height() * multiplier);
auto leftover_width = abs(relative_rect.width() - zoomed_rect.width());
auto leftover_height = abs(relative_rect.height() - zoomed_rect.height());
double cursor_x_percentage = static_cast<double>(event.position().x()) / relative_rect.width();
double cursor_y_percentage = static_cast<double>(event.position().y()) / relative_rect.height();
zoomed_rect.set_x((zooming_in ? 1 : -1) * leftover_width * cursor_x_percentage);
zoomed_rect.set_y((zooming_in ? 1 : -1) * leftover_height * cursor_y_percentage);
m_set.zoom(zoomed_rect);
update();
zoom(event.wheel_delta() < 0 ? Zoom::In : Zoom::Out, event.position());
}
void Mandelbrot::resize_event(GUI::ResizeEvent& event)