From 3c0e17f29f9cff870f4cb609f3177ad580f8d4ee Mon Sep 17 00:00:00 2001
From: MacDue <macdue@dueutil.tech>
Date: Sat, 19 Mar 2022 00:29:22 +0000
Subject: [PATCH] LibGfx: Support scaling in AntiAliasingPainter::draw_circle()

Previously the painter would crash if scaling was enabled.
---
 Userland/Libraries/LibGfx/AntiAliasingPainter.cpp | 7 +++++--
 Userland/Libraries/LibGfx/Painter.cpp             | 6 +++---
 Userland/Libraries/LibGfx/Painter.h               | 3 ++-
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/Userland/Libraries/LibGfx/AntiAliasingPainter.cpp b/Userland/Libraries/LibGfx/AntiAliasingPainter.cpp
index 31c51edf60..8d6cbe1010 100644
--- a/Userland/Libraries/LibGfx/AntiAliasingPainter.cpp
+++ b/Userland/Libraries/LibGfx/AntiAliasingPainter.cpp
@@ -193,6 +193,9 @@ void Gfx::AntiAliasingPainter::draw_circle(IntPoint center, int radius, Color co
     Inline comments are from the paper.
     */
 
+    center *= m_underlying_painter.scale();
+    radius *= m_underlying_painter.scale();
+
     // TODO: Generalize to ellipses (see paper)
 
     // These happen to be the same here, but are treated separately in the paper:
@@ -352,11 +355,11 @@ void Gfx::AntiAliasingPainter::fill_rect_with_rounded_corners(IntRect const& a_r
         a_rect.x() + a_rect.width() - top_right_radius,
         a_rect.y() + top_right_radius,
     };
-    IntPoint bottom_right_corner {
+    IntPoint bottom_left_corner {
         a_rect.x() + bottom_left_radius,
         a_rect.y() + a_rect.height() - bottom_right_radius
     };
-    IntPoint bottom_left_corner {
+    IntPoint bottom_right_corner {
         a_rect.x() + a_rect.width() - bottom_left_radius,
         a_rect.y() + a_rect.height() - bottom_left_radius
     };
diff --git a/Userland/Libraries/LibGfx/Painter.cpp b/Userland/Libraries/LibGfx/Painter.cpp
index 91e12bd240..1f148e647b 100644
--- a/Userland/Libraries/LibGfx/Painter.cpp
+++ b/Userland/Libraries/LibGfx/Painter.cpp
@@ -1713,11 +1713,11 @@ void Painter::draw_text(Function<void(IntRect const&, Utf8CodePointIterator&)> d
 
 void Painter::set_pixel(IntPoint const& p, Color color, bool blend)
 {
-    VERIFY(scale() == 1); // FIXME: Add scaling support.
-
     auto point = p;
     point.translate_by(state().translation);
-    if (!clip_rect().contains(point))
+    // Use the scale only to avoid clipping pixels set in drawing functions that handle
+    // scaling and call set_pixel() -- do not scale the pixel.
+    if (!clip_rect().contains(point / scale()))
         return;
     auto& dst = m_target->scanline(point.y())[point.x()];
     if (!blend) {
diff --git a/Userland/Libraries/LibGfx/Painter.h b/Userland/Libraries/LibGfx/Painter.h
index 445ddf8677..fedb6433ca 100644
--- a/Userland/Libraries/LibGfx/Painter.h
+++ b/Userland/Libraries/LibGfx/Painter.h
@@ -145,11 +145,12 @@ public:
 
     IntRect clip_rect() const { return state().clip_rect; }
 
+    int scale() const { return state().scale; }
+
 protected:
     IntPoint translation() const { return state().translation; }
     IntRect to_physical(IntRect const& r) const { return r.translated(translation()) * scale(); }
     IntPoint to_physical(IntPoint const& p) const { return p.translated(translation()) * scale(); }
-    int scale() const { return state().scale; }
     void set_physical_pixel_with_draw_op(u32& pixel, Color const&);
     void fill_physical_scanline_with_draw_op(int y, int x, int width, Color const& color);
     void fill_rect_with_draw_op(IntRect const&, Color);