fix: remove redundant palette setup in RoundScrollArea

1. Removed unnecessary palette initialization in constructor that was
setting window brush to transparent
2. Changed paintEvent to directly use Qt::transparent instead of
palette().window()
3. This simplifies the code while maintaining the same visual effect
of transparency
4. The palette setup was redundant since we're manually painting the
background anyway

fix: 移除RoundScrollArea,使用QScrollArea.

1. 移除RoundScrollArea
2. 修改paintEvent直接使用Qt::transparent替代palette().window()
3. 在保持相同透明视觉效果的同时简化了代码
4. 调色板设置是多余的，因为我们已经手动绘制背景

Pms: bug-315535

Author: wjyrich

plugins/dde-dock/brightness/CMakeLists.txt

@@ -14,8 +14,6 @@ file(GLOB_RECURSE SRCS
     "../widgets/*.cpp"
     "../common/*.h"
     "../common/*.cpp"
-    "../util/roundscrollarea.h"
-    "../util/roundscrollarea.cpp"
     "../dbus/types/*.h"
     "../dbus/types/*.cpp"
 )

plugins/dde-dock/brightness/brightnessapplet.cpp

@@ -22,7 +22,7 @@ DWIDGET_USE_NAMESPACE
 BrightnessApplet::BrightnessApplet(QWidget* parent)
     : QWidget(parent)
     , m_titleWidget(new QWidget(this))
-    , m_scrollArea(new RoundScrollArea(this))
+    , m_scrollArea(new QScrollArea(this))
     , m_monitorsLayout(nullptr)
     , m_jumpSettingButton(new JumpSettingButton(this))
     , m_minHeight(-1)
@@ -58,7 +58,6 @@ void BrightnessApplet::initUI()
     widget->setAttribute(Qt::WA_TranslucentBackground);
     widget->setLayout(m_monitorsLayout);
     m_scrollArea->setWidget(widget);
-    m_scrollArea->setRadius(0);
     m_scrollArea->setWidgetResizable(true);
     m_scrollArea->setFrameStyle(QFrame::NoFrame);
     m_scrollArea->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);

plugins/dde-dock/brightness/brightnessapplet.h

@@ -8,7 +8,6 @@
 #include "jumpsettingbutton.h"
 #include "monitor.h"
 #include "slidercontainer.h"
-#include "roundscrollarea.h"
 
 #include <QWidget>
 #include <QScrollArea>
@@ -39,7 +38,7 @@ class BrightnessApplet : public QWidget
 
 private:
     QWidget *m_titleWidget;
-    RoundScrollArea *m_scrollArea;
+    QScrollArea *m_scrollArea;
     QVBoxLayout *m_monitorsLayout;
     JumpSettingButton *m_jumpSettingButton;
     int m_minHeight;