PaintBrush: Implement a thickness setting for the pen tool.

Painter gains the ability to draw lines with arbitrary thickness.
It's basically implemented by drawing filled rects for thickness>1.

In PaintBrush, Tool classes can now override on_contextmenu() to
provide a context menu for the toolbox button. :^)

Applications/PaintBrush/PenTool.cpp

@@ -1,5 +1,7 @@
 #include "PenTool.h"
 #include "PaintableWidget.h"
+#include <LibGUI/GAction.h>
+#include <LibGUI/GMenu.h>
 #include <LibGUI/GPainter.h>
 
 PenTool::PenTool()
@@ -16,8 +18,8 @@ void PenTool::on_mousedown(GMouseEvent& event)
         return;
 
     GPainter painter(m_widget->bitmap());
-    painter.set_pixel(event.position(), m_widget->color_for(event));
-    m_widget->update({ event.position(), { 1, 1 } });
+    painter.draw_line(event.position(), event.position(), m_widget->color_for(event), m_thickness);
+    m_widget->update();
     m_last_drawing_event_position = event.position();
 }
 
@@ -35,14 +37,32 @@ void PenTool::on_mousemove(GMouseEvent& event)
     if (event.buttons() & GMouseButton::Left || event.buttons() & GMouseButton::Right) {
         GPainter painter(m_widget->bitmap());
 
-        if (m_last_drawing_event_position != Point(-1, -1)) {
-            painter.draw_line(m_last_drawing_event_position, event.position(), m_widget->color_for(event));
-            m_widget->update();
-        } else {
-            painter.set_pixel(event.position(), m_widget->color_for(event));
-            m_widget->update({ event.position(), { 1, 1 } });
-        }
+        if (m_last_drawing_event_position != Point(-1, -1))
+            painter.draw_line(m_last_drawing_event_position, event.position(), m_widget->color_for(event), m_thickness);
+        else
+            painter.draw_line(event.position(), event.position(), m_widget->color_for(event), m_thickness);
+        m_widget->update();
 
         m_last_drawing_event_position = event.position();
     }
 }
+
+void PenTool::on_contextmenu(GContextMenuEvent& event)
+{
+    if (!m_context_menu) {
+        m_context_menu = make<GMenu>("PenTool Context Menu");
+        m_context_menu->add_action(GAction::create("1", [this](auto&) {
+            m_thickness = 1;
+        }));
+        m_context_menu->add_action(GAction::create("2", [this](auto&) {
+            m_thickness = 2;
+        }));
+        m_context_menu->add_action(GAction::create("3", [this](auto&) {
+            m_thickness = 3;
+        }));
+        m_context_menu->add_action(GAction::create("4", [this](auto&) {
+            m_thickness = 4;
+        }));
+    }
+    m_context_menu->popup(event.screen_position());
+}

Applications/PaintBrush/PenTool.h

@@ -3,6 +3,8 @@
 #include "Tool.h"
 #include <SharedGraphics/Point.h>
 
+class GMenu;
+
 class PenTool final : public Tool {
 public:
     PenTool();
@@ -11,9 +13,12 @@ public:
     virtual void on_mousedown(GMouseEvent&) override;
     virtual void on_mousemove(GMouseEvent&) override;
     virtual void on_mouseup(GMouseEvent&) override;
+    virtual void on_contextmenu(GContextMenuEvent&) override;
 
 private:
     virtual const char* class_name() const override { return "PenTool"; }
 
     Point m_last_drawing_event_position { -1, -1 };
+    OwnPtr<GMenu> m_context_menu;
+    int m_thickness { 1 };
 };

Applications/PaintBrush/Tool.h

@@ -12,6 +12,7 @@ public:
     virtual void on_mousedown(GMouseEvent&) { }
     virtual void on_mousemove(GMouseEvent&) { }
     virtual void on_mouseup(GMouseEvent&) { }
+    virtual void on_contextmenu(GContextMenuEvent&) { }
 
     void clear() { m_widget = nullptr; }
     void setup(PaintableWidget& widget) { m_widget = widget.make_weak_ptr(); }

Applications/PaintBrush/ToolboxWidget.cpp

@@ -20,6 +20,11 @@ public:
     const Tool& tool() const { return *m_tool; }
     Tool& tool() { return *m_tool; }
 
+    virtual void context_menu_event(GContextMenuEvent& event) override
+    {
+        m_tool->on_contextmenu(event);
+    }
+
 private:
     OwnPtr<Tool> m_tool;
 };

SharedGraphics/Painter.cpp

@@ -636,7 +636,16 @@ void Painter::set_pixel(const Point& p, Color color)
         pixel ^= color.value();
 }
 
-void Painter::draw_line(const Point& p1, const Point& p2, Color color)
+void Painter::draw_pixel(const Point& position, Color color, int thickness)
+{
+    ASSERT(draw_op() == DrawOp::Copy);
+    if (thickness == 1)
+        return set_pixel_with_draw_op(m_target->scanline(position.y())[position.x()], color);
+    Rect rect { position.translated(-(thickness / 2), -(thickness / 2)), { thickness, thickness } };
+    fill_rect(rect, color);
+}
+
+void Painter::draw_line(const Point& p1, const Point& p2, Color color, int thickness)
 {
     auto clip_rect = this->clip_rect();
 
@@ -660,7 +669,7 @@ void Painter::draw_line(const Point& p1, const Point& p2, Color color)
         int min_y = max(point1.y(), clip_rect.top());
         int max_y = min(point2.y(), clip_rect.bottom());
         for (int y = min_y; y <= max_y; ++y)
-            set_pixel_with_draw_op(m_target->scanline(y)[x], color);
+            draw_pixel({ x, y }, color, thickness);
         return;
     }
 
@@ -677,13 +686,8 @@ void Painter::draw_line(const Point& p1, const Point& p2, Color color)
             return;
         int min_x = max(point1.x(), clip_rect.left());
         int max_x = min(point2.x(), clip_rect.right());
-        auto* pixels = m_target->scanline(point1.y());
-        if (draw_op() == DrawOp::Copy) {
-            fast_dword_fill(pixels + min_x, color.value(), max_x - min_x + 1);
-        } else {
-            for (int x = min_x; x <= max_x; ++x)
-                set_pixel_with_draw_op(pixels[x], color);
-        }
+        for (int x = min_x; x <= max_x; ++x)
+            draw_pixel({ x, y }, color, thickness);
         return;
     }
 
@@ -709,7 +713,7 @@ void Painter::draw_line(const Point& p1, const Point& p2, Color color)
         int y = point1.y();
         for (int x = point1.x(); x <= point2.x(); ++x) {
             if (clip_rect.contains(x, y))
-                m_target->scanline(y)[x] = color.value();
+                draw_pixel({ x, y }, color, thickness);
             error += delta_error;
             if (error >= 0.5) {
                 y = (double)y + y_step;
@@ -722,7 +726,7 @@ void Painter::draw_line(const Point& p1, const Point& p2, Color color)
         int x = point1.x();
         for (int y = point1.y(); y <= point2.y(); ++y) {
             if (clip_rect.contains(x, y))
-                m_target->scanline(y)[x] = color.value();
+                draw_pixel({ x, y }, color, thickness);
             error += delta_error;
             if (error >= 0.5) {
                 x = (double)x + x_step;

SharedGraphics/Painter.h

@@ -23,7 +23,7 @@ public:
     void draw_bitmap(const Point&, const CharacterBitmap&, Color = Color());
     void draw_bitmap(const Point&, const GlyphBitmap&, Color = Color());
     void set_pixel(const Point&, Color);
-    void draw_line(const Point&, const Point&, Color);
+    void draw_line(const Point&, const Point&, Color, int thickness = 1);
     void draw_scaled_bitmap(const Rect& dst_rect, const GraphicsBitmap&, const Rect& src_rect);
     void blit(const Point&, const GraphicsBitmap&, const Rect& src_rect, float opacity = 1.0f);
     void blit_dimmed(const Point&, const GraphicsBitmap&, const Rect& src_rect);
@@ -68,6 +68,7 @@ protected:
     void fill_rect_with_draw_op(const Rect&, Color);
     void blit_with_alpha(const Point&, const GraphicsBitmap&, const Rect& src_rect);
     void blit_with_opacity(const Point&, const GraphicsBitmap&, const Rect& src_rect, float opacity);
+    void draw_pixel(const Point&, Color, int thickness = 1);
 
     struct State {
         const Font* font;