Disable Brush Preview in Preview window by default (fix #4721, #4752)

data/gui.xml

@@ -1043,6 +1043,7 @@
             <param name="preview" value="true" />
             <param name="checkedIfZero" value="true" />
           </item>
+          <item command="ShowBrushPreviewInPreview" text="@.view_preview_brush_preview"/>
         </menu>
         <item command="AdvancedMode" text="@.view_advanced_mode" />
         <item command="FullscreenMode" text="@.view_full_screen_mode" />

data/pref.xml

@@ -608,6 +608,7 @@
       <option id="grid" type="bool" default="false" />
       <option id="pixel_grid" type="bool" default="false" />
       <option id="brush_preview" type="bool" default="true" />
+      <option id="brush_preview_in_preview" type="bool" default="false" />
       <option id="slices" type="bool" default="true" />
       <option id="auto_guides" type="bool" default="true" />
       <option id="tile_numbers" type="bool" default="true" />

data/strings/en.ini

@@ -441,6 +441,7 @@ SetPlaybackSpeed = Playback Speed {0}x
 SetSameInk = Same Ink in All Tools
 ShowAutoGuides = Show Auto Guides
 ShowBrushPreview = Show Brush Preview
+ShowBrushPreviewInPreview = Show Brush Preview in Preview
 ShowBrushes = Show Brushes
 ShowDynamics = Show Dynamics
 ShowExtras = Show Extras
@@ -1167,6 +1168,7 @@ view_show_onion_skin = Show &Onion Skin
 view_timeline = &Timeline
 view_preview = Previe&w
 view_preview_hide_other_layers = &Hide Other Layers
+view_preview_brush_preview = &Brush Preview
 view_advanced_mode = &Advanced Mode
 view_full_screen_mode = &Full Screen Mode
 view_full_screen_preview = F&ull Screen Preview
@@ -1425,6 +1427,7 @@ brush_preview_edges = Edges Only
 brush_preview_full = Full Preview
 brush_preview_fullall = Full Preview with All Tools
 brush_preview_fullnedges = Full Preview and Edges
+brush_preview_in_preview = Brush Preview in Preview
 cursor_color_type = Crosshair && Brush Edges Color:
 cursor_neg_bw = Negative Black and White
 cursor_specific_color = Specific Color

src/app/commands/cmd_show.cpp

@@ -148,6 +148,24 @@ protected:
   }
 };
 
+class ShowBrushPreviewInPreviewCommand : public Command {
+public:
+  ShowBrushPreviewInPreviewCommand()
+    : Command(CommandId::ShowBrushPreviewInPreview(), CmdUIOnlyFlag) {
+  }
+
+protected:
+  bool onChecked(Context* ctx) override {
+    DocumentPreferences& docPref = Preferences::instance().document(ctx->activeDocument());
+    return docPref.show.brushPreviewInPreview();
+  }
+
+  void onExecute(Context* ctx) override {
+    DocumentPreferences& docPref = Preferences::instance().document(ctx->activeDocument());
+    docPref.show.brushPreviewInPreview(!docPref.show.brushPreviewInPreview());
+  }
+};
+
 class ShowAutoGuidesCommand : public Command {
 public:
   ShowAutoGuidesCommand()
@@ -232,6 +250,11 @@ Command* CommandFactory::createShowBrushPreviewCommand()
   return new ShowBrushPreviewCommand;
 }
 
+Command* CommandFactory::createShowBrushPreviewInPreviewCommand()
+{
+  return new ShowBrushPreviewInPreviewCommand;
+}
+
 Command* CommandFactory::createShowAutoGuidesCommand()
 {
   return new ShowAutoGuidesCommand;

src/app/commands/commands_list.h

@@ -145,6 +145,7 @@ FOR_EACH_COMMAND(SetPlaybackSpeed)
 FOR_EACH_COMMAND(SetSameInk)
 FOR_EACH_COMMAND(ShowAutoGuides)
 FOR_EACH_COMMAND(ShowBrushPreview)
+FOR_EACH_COMMAND(ShowBrushPreviewInPreview)
 FOR_EACH_COMMAND(ShowExtras)
 FOR_EACH_COMMAND(ShowGrid)
 FOR_EACH_COMMAND(ShowLayerEdges)

src/app/ui/editor/editor.cpp

@@ -704,13 +704,15 @@ void Editor::drawOneSpriteUnclippedRect(ui::Graphics* g, const gfx::Rect& sprite
 
     ExtraCelRef extraCel = m_document->extraCel();
     if (extraCel &&
-        extraCel->type() != render::ExtraType::NONE) {
-      m_renderEngine->setExtraImage(
-        extraCel->type(),
-        extraCel->cel(),
-        extraCel->image(),
-        extraCel->blendMode(),
-        m_layer, m_frame);
+        extraCel->type() != render::ExtraType::NONE &&
+        (!m_docView->isPreview() ||
+         m_docPref.show.brushPreviewInPreview())) {
+      m_renderEngine->setExtraImage(extraCel->type(),
+                                    extraCel->cel(),
+                                    extraCel->image(),
+                                    extraCel->blendMode(),
+                                    m_layer,
+                                    m_frame);
     }
 
     // Render background first (e.g. new ShaderRenderer will paint the