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PaintBrush: Shift key constrains LineTool angle

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Holding Shift key will constrain the LineTool's line angle to 15 degrees
increments. Many graphics editors have similar feature.
This commit is contained in:
Zyper 2019-12-17 13:06:52 +01:00 • committed by Andreas Kling
parent b185c7f58a
commit 413618454b
Notes: sideshowbarker 2024-07-19 10:49:38 +09:00
2 changed files with 37 additions and 1 deletions
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34
Applications/PaintBrush/LineTool.cpp
View file

@ -3,6 +3,20 @@
#include <LibGUI/GAction.h>
#include <LibGUI/GMenu.h>
#include <LibGUI/GPainter.h>
#include <LibM/math.h>
Point constrain_line_angle(const Point& start_pos, const Point& end_pos, float angle_increment)
{
float current_angle = atan2(end_pos.y() - start_pos.y(), end_pos.x() - start_pos.x()) + M_PI * 2.;
float constrained_angle = ((int)((current_angle + angle_increment / 2.) / angle_increment)) * angle_increment;
auto diff = end_pos - start_pos;
float line_length = sqrt(diff.x() * diff.x() + diff.y() * diff.y());
return { start_pos.x() + (int)(cos(constrained_angle) * line_length),
start_pos.y() + (int)(sin(constrained_angle) * line_length) };
}
LineTool::LineTool()
{
@ -44,7 +58,12 @@ void LineTool::on_mousemove(GMouseEvent& event)
if (!m_widget->rect().contains(event.position()))
return;
if (!m_constrain_angle) {
m_line_end_position = event.position();
} else {
const float ANGLE_STEP = M_PI / 8.0f;
m_line_end_position = constrain_line_angle(m_line_start_position, event.position(), ANGLE_STEP);
}
m_widget->update();
}
@ -65,6 +84,21 @@ void LineTool::on_keydown(GKeyEvent& event)
m_widget->update();
event.accept();
}
if (event.key() == Key_Shift) {
m_constrain_angle = true;
m_widget->update();
event.accept();
}
}
void LineTool::on_keyup(GKeyEvent& event)
{
if (event.key() == Key_Shift) {
m_constrain_angle = false;
m_widget->update();
event.accept();
}
}
void LineTool::on_contextmenu(GContextMenuEvent& event)

2
Applications/PaintBrush/LineTool.h
View file

@ -16,6 +16,7 @@ public:
virtual void on_contextmenu(GContextMenuEvent&) override;
virtual void on_second_paint(GPaintEvent&) override;
virtual void on_keydown(GKeyEvent&) override;
virtual void on_keyup(GKeyEvent&) override;
private:
virtual const char* class_name() const override { return "LineTool"; }
@ -25,4 +26,5 @@ private:
Point m_line_end_position;
RefPtr<GMenu> m_context_menu;
int m_thickness { 1 };
bool m_constrain_angle { false };
};