From efb2bed5250755556df57a6a0a95313e1022fbaf Mon Sep 17 00:00:00 2001
From: MacDue <macdue@dueutil.tech>
Date: Thu, 26 Jan 2023 20:40:10 +0000
Subject: [PATCH] PixelPaint: Fix off-by-one in on_second_paint() clip rect

Previously the clip rect did not include the 1px border at the edges
of the rulers.
---
 Userland/Applications/PixelPaint/ImageEditor.cpp | 16 +++++++++++-----
 Userland/Applications/PixelPaint/ImageEditor.h   |  2 ++
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/Userland/Applications/PixelPaint/ImageEditor.cpp b/Userland/Applications/PixelPaint/ImageEditor.cpp
index 70626e150f..7e776e23c8 100644
--- a/Userland/Applications/PixelPaint/ImageEditor.cpp
+++ b/Userland/Applications/PixelPaint/ImageEditor.cpp
@@ -134,6 +134,16 @@ void ImageEditor::update_modified()
         on_modified_change(is_modified());
 }
 
+Gfx::IntRect ImageEditor::subtract_rulers_from_rect(Gfx::IntRect const& rect) const
+{
+    Gfx::IntRect clipped_rect {};
+    clipped_rect.set_top(max(rect.y(), m_ruler_thickness + 1));
+    clipped_rect.set_left(max(rect.x(), m_ruler_thickness + 1));
+    clipped_rect.set_bottom(rect.bottom());
+    clipped_rect.set_right(rect.right());
+    return clipped_rect;
+}
+
 void ImageEditor::paint_event(GUI::PaintEvent& event)
 {
     GUI::Frame::paint_event(event);
@@ -282,11 +292,7 @@ void ImageEditor::second_paint_event(GUI::PaintEvent& event)
 {
     if (m_active_tool) {
         if (m_show_rulers) {
-            auto clipped_event = GUI::PaintEvent(Gfx::IntRect { event.rect().x() + m_ruler_thickness,
-                                                     event.rect().y() + m_ruler_thickness,
-                                                     event.rect().width() - m_ruler_thickness,
-                                                     event.rect().height() - m_ruler_thickness },
-                event.window_size());
+            auto clipped_event = GUI::PaintEvent(subtract_rulers_from_rect(event.rect()), event.window_size());
             m_active_tool->on_second_paint(m_active_layer, clipped_event);
         } else {
             m_active_tool->on_second_paint(m_active_layer, event);
diff --git a/Userland/Applications/PixelPaint/ImageEditor.h b/Userland/Applications/PixelPaint/ImageEditor.h
index 97da298482..727868247f 100644
--- a/Userland/Applications/PixelPaint/ImageEditor.h
+++ b/Userland/Applications/PixelPaint/ImageEditor.h
@@ -148,6 +148,8 @@ private:
 
     virtual void selection_did_change() override;
 
+    Gfx::IntRect subtract_rulers_from_rect(Gfx::IntRect const& rect) const;
+
     GUI::MouseEvent event_adjusted_for_layer(GUI::MouseEvent const&, Layer const&) const;
     GUI::MouseEvent event_with_pan_and_scale_applied(GUI::MouseEvent const&) const;