LibGfx+Everywhere: Change `Gfx::Rect` to be endpoint exclusive

Previously, calling `.right()` on a `Gfx::Rect` would return the last
column's coordinate still inside the rectangle, or `left + width - 1`.
This is called 'endpoint inclusive' and does not make a lot of sense for
`Gfx::Rect<float>` where a rectangle of width 5 at position (0, 0) would
return 4 as its right side. This same problem exists for `.bottom()`.

This changes `Gfx::Rect` to be endpoint exclusive, which gives us the
nice property that `width = right - left` and `height = bottom - top`.
It enables us to treat `Gfx::Rect<int>` and `Gfx::Rect<float>` exactly
the same.

All users of `Gfx::Rect` have been updated accordingly.

1 files changed, 1 insertions, 1 deletions

diff --git a/Userland/Libraries/LibGUI/TreeView.cpp b/Userland/Libraries/LibGUI/TreeView.cpp
index a8a4322465..7407cd29b9 100644
--- a/Userland/Libraries/LibGUI/TreeView.cpp
+++ b/Userland/Libraries/LibGUI/TreeView.cpp
@@ -327,7 +327,7 @@ void TreeView::paint_event(PaintEvent& event)
                 Gfx::IntRect icon_rect = { rect.x(), rect.y(), icon_size(), icon_size() };
                 icon_rect.center_vertically_within(rect);
                 Gfx::IntRect background_rect = {
-                    icon_rect.right() + 1 + icon_spacing(), rect.y(),
+                    icon_rect.right() + icon_spacing(), rect.y(),
                     min(rect.width(), column_width - indent_width) - icon_size() - icon_spacing(), rect.height()
                 };
                 Gfx::IntRect text_rect = background_rect.shrunken(text_padding() * 2, 0);