Add adjustable transparency to album art background.

Fixes issue #3431

src/playlist/playlistview.cpp

@@ -51,10 +51,6 @@ const int PlaylistView::kGlowIntensitySteps = 24;
 const int PlaylistView::kAutoscrollGraceTimeout = 60; // seconds
 const int PlaylistView::kDropIndicatorWidth = 2;
 const int PlaylistView::kDropIndicatorGradientWidth = 5;
-// Opacity value used by all background images but the default clementine one
-// (because it is already opaque and load through the mainwindow.css file)
-const qreal PlaylistView::kBackgroundOpacity = 0.4;
-
 const char* PlaylistView::kSettingBackgroundImageType = "playlistview_background_type";
 const char* PlaylistView::kSettingBackgroundImageFilename = "playlistview_background_image_file";
 
@@ -1020,6 +1016,7 @@ void PlaylistView::ReloadSettings() {
   }
   QString background_image_filename = s.value(kSettingBackgroundImageFilename).toString();
   int blur_radius = s.value("blur_radius").toInt();
+  int opacity_level = s.value("opacity_level").toInt();
   // Check if background properties have changed.
   // We change properties only if they have actually changed, to avoid to call
   // set_background_image when it is not needed, as this will cause the fading
@@ -1027,11 +1024,13 @@ void PlaylistView::ReloadSettings() {
   // "force_background_redraw".
   if (background_image_filename != background_image_filename_ ||
       background_type != background_image_type_ ||
-      blur_radius_ != blur_radius) {
+      blur_radius_ != blur_radius ||
+      opacity_level_ != opacity_level) {
     // Store background properties
     background_image_type_ = background_type;
     background_image_filename_ = background_image_filename;
     blur_radius_ = blur_radius;
+    opacity_level_ = opacity_level;
     if (background_image_type_ == Custom) {
       set_background_image(QImage(background_image_filename));
     } else if (background_image_type_ == AlbumCover) {
@@ -1198,7 +1197,7 @@ void PlaylistView::set_background_image(const QImage& image) {
   // Apply opacity filter
   uchar* bits = background_image_.bits();
   for (int i = 0; i < background_image_.height() * background_image_.bytesPerLine(); i+=4) {
-    bits[i+3] = kBackgroundOpacity * 255;
+    bits[i+3] = (opacity_level_ / 100.0) * 255;
   }
 
   if (blur_radius_ != 0) {

src/playlist/playlistview.h

@@ -173,7 +173,6 @@ class PlaylistView : public QTreeView {
   static const int kAutoscrollGraceTimeout;
   static const int kDropIndicatorWidth;
   static const int kDropIndicatorGradientWidth;
-  static const qreal kBackgroundOpacity;
 
   QList<int> GetEditableColumns();
   QModelIndex NextEditableIndex(const QModelIndex& current);
@@ -196,6 +195,7 @@ class PlaylistView : public QTreeView {
   // set_background_image_type instead of modifying background_image_ directly
   QImage background_image_;
   int blur_radius_;
+  int opacity_level_;
   // Used if background image is a filemane
   QString background_image_filename_;
   QImage current_song_cover_art_;

src/ui/appearancesettingspage.cpp

@@ -57,6 +57,7 @@ AppearanceSettingsPage::AppearanceSettingsPage(SettingsDialog* dialog)
   connect(ui_->select_background_color, SIGNAL(pressed()), SLOT(SelectBackgroundColor()));
   connect(ui_->use_a_custom_color_set, SIGNAL(toggled(bool)), SLOT(UseCustomColorSetOptionChanged(bool)));
   connect(ui_->blur_slider, SIGNAL(valueChanged(int)), SLOT(BlurLevelChanged(int)));
+  connect(ui_->opacity_slider, SIGNAL(valueChanged(int)), SLOT(OpacityLevelChanged(int)));
 
   connect(ui_->select_background_image_filename_button, SIGNAL(pressed()), SLOT(SelectBackgroundImage()));
   connect(ui_->use_custom_background_image, SIGNAL(toggled(bool)),
@@ -127,6 +128,10 @@ void AppearanceSettingsPage::Load() {
       DisableBlurSlider(true);
   }
   ui_->background_image_filename->setText(playlist_view_background_image_filename_);
+  /* There has to be a way to just simulate the change... */
+  ui_->opacity_slider->setValue(s.value("opacity_level").toInt());
+  OpacityLevelChanged(s.value("opacity_level").toInt());
+
 
   s.endGroup();
 
@@ -171,6 +176,7 @@ void AppearanceSettingsPage::Save() {
   s.setValue(PlaylistView::kSettingBackgroundImageType,
              playlist_view_background_image_type_);
   s.setValue("blur_radius", ui_->blur_slider->value());
+  s.setValue("opacity_level", ui_->opacity_slider->value());
   s.endGroup();
 
   // Moodbar settings
@@ -252,6 +258,11 @@ void AppearanceSettingsPage::BlurLevelChanged(int value) {
   ui_->background_blur_radius_label->setText(QString("%1px").arg(value));
 }
 
+void AppearanceSettingsPage::OpacityLevelChanged(int percent) {
+  background_opacity_level_ = percent;
+  ui_->background_opacity_label->setText(QString("%1\%").arg(percent));
+}
+
 void AppearanceSettingsPage::InitMoodbarPreviews() {
 #ifdef HAVE_MOODBAR
   if (initialised_moodbar_previews_)

src/ui/appearancesettingspage.h

@@ -43,6 +43,7 @@ private slots:
   void UseCustomColorSetOptionChanged(bool);
   void SelectBackgroundImage();
   void BlurLevelChanged(int);
+  void OpacityLevelChanged(int);
   void DisableBlurSlider(bool);
 
 private:
@@ -65,6 +66,7 @@ private:
   PlaylistView::BackgroundImageType playlist_view_background_image_type_;
   QString playlist_view_background_image_filename_;
   int background_blur_radius_;
+  int background_opacity_level_;
 
   bool initialised_moodbar_previews_;
 };

src/ui/appearancesettingspage.ui

@@ -201,6 +201,37 @@
         </item>
        </layout>
       </item>
+      <item>
+       <layout class="QHBoxLayout" name="horizontalLayout_9">
+        <item>
+         <widget class="QLabel" name="select_opacity_level_label">
+          <property name="text">
+           <string>Opacity level:</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QLabel" name="background_opacity_label">
+          <property name="text">
+           <string>40%</string>
+          </property>
+         </widget>
+        </item>
+        <item>
+         <widget class="QSlider" name="opacity_slider">
+          <property name="maximum">
+           <number>100</number>
+          </property>
+          <property name="value">
+           <number>40</number>
+          </property>
+          <property name="orientation">
+           <enum>Qt::Horizontal</enum>
+          </property>
+         </widget>
+        </item>
+       </layout>
+      </item>
      </layout>
     </widget>
    </item>