From 9b0ff229e378bc7b01758ba3f094eeb46d75625a Mon Sep 17 00:00:00 2001
From: Aziz Berkay Yesilyurt <abyesilyurt@gmail.com>
Date: Fri, 9 Jul 2021 11:42:03 +0200
Subject: [PATCH] Utilities: Use alpha channel instead of opacity in shot

The way overlay was drawn is not the correct way to achieve window
transparency in selection mode. With this change, shot window becomes
truely transparent.
---
 Userland/Utilities/shot.cpp | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/Userland/Utilities/shot.cpp b/Userland/Utilities/shot.cpp
index 6ccd4e9433..f920e7b577 100644
--- a/Userland/Utilities/shot.cpp
+++ b/Userland/Utilities/shot.cpp
@@ -25,7 +25,7 @@ class SelectableLayover final : public GUI::Widget {
 public:
     SelectableLayover(GUI::Window* window)
         : m_window(window)
-        , m_background_color(palette().threed_highlight())
+        , m_background_color(palette().threed_highlight().with_alpha(128))
     {
         set_override_cursor(Gfx::StandardCursor::Crosshair);
     }
@@ -60,16 +60,14 @@ private:
 
     virtual void paint_event(GUI::PaintEvent&) override
     {
-        if (m_region.is_empty()) {
-            GUI::Painter painter(*this);
-            painter.fill_rect(m_window->rect(), m_background_color);
-            return;
-        }
-
         GUI::Painter painter(*this);
-        painter.fill_rect(m_region, Gfx::Color::Transparent);
-        for (auto rect : m_window->rect().shatter(m_region))
-            painter.fill_rect(rect, m_background_color);
+        painter.clear_rect(m_window->rect(), Gfx::Color::Transparent);
+        painter.fill_rect(m_window->rect(), m_background_color);
+
+        if (m_region.is_empty())
+            return;
+
+        painter.clear_rect(m_region, Gfx::Color::Transparent);
     }
 
     virtual void keydown_event(GUI::KeyEvent& event) override
@@ -113,10 +111,9 @@ int main(int argc, char** argv)
     if (select_region) {
         auto window = GUI::Window::construct();
         auto& container = window->set_main_widget<SelectableLayover>(window);
-        container.set_fill_with_background_color(true);
 
         window->set_title("shot");
-        window->set_opacity(0.2);
+        window->set_has_alpha_channel(true);
         window->set_fullscreen(true);
         window->show();
         app->exec();