Always show transformation preview on Preview window

Fix regression from cd5bf499eab932061b10a8f0a22d6781e099c909

src/app/extra_cel.cpp

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2020  Igara Studio S.A.
+// Copyright (C) 2020-2024  Igara Studio S.A.
 // Copyright (C) 2001-2016  David Capello
 //
 // This program is distributed under the terms of
@@ -16,12 +16,14 @@
 namespace app {
 
 ExtraCel::ExtraCel()
-  : m_type(render::ExtraType::NONE)
+  : m_purpose(Purpose::Unknown)
+  , m_type(render::ExtraType::NONE)
   , m_blendMode(doc::BlendMode::NORMAL)
 {
 }
 
-void ExtraCel::create(const TilemapMode tilemapMode,
+void ExtraCel::create(Purpose purpose,
+                      const TilemapMode tilemapMode,
                       doc::Sprite* sprite,
                       const gfx::Rect& bounds,
                       const gfx::Size& imageSize,
@@ -30,6 +32,8 @@ void ExtraCel::create(const TilemapMode tilemapMode,
 {
   ASSERT(sprite);
 
+  m_purpose = purpose;
+
   doc::PixelFormat pixelFormat;
   if (tilemapMode == TilemapMode::Tiles)
     pixelFormat = doc::IMAGE_TILEMAP;
@@ -60,6 +64,7 @@ void ExtraCel::create(const TilemapMode tilemapMode,
 
 void ExtraCel::reset()
 {
+  m_purpose = Purpose::Unknown;
   m_type = render::ExtraType::NONE;
   m_image.reset();
   m_cel.reset();

src/app/extra_cel.h

@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019-2020  Igara Studio S.A.
+// Copyright (C) 2019-2024  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -29,9 +29,16 @@ namespace app {
 
   class ExtraCel {
   public:
+    enum class Purpose {
+      Unknown,
+      BrushPreview,
+      TransformationPreview,
+    };
+
     ExtraCel();
 
-    void create(const TilemapMode tilemapMode,
+    void create(Purpose purpose,
+                const TilemapMode tilemapMode,
                 doc::Sprite* sprite,
                 const gfx::Rect& bounds,
                 const gfx::Size& imageSize,
@@ -39,6 +46,8 @@ namespace app {
                 const int opacity);
     void reset();
 
+    Purpose purpose() const { return m_purpose; }
+
     render::ExtraType type() const { return m_type; }
     void setType(render::ExtraType type) { m_type = type; }
 
@@ -49,6 +58,7 @@ namespace app {
     void setBlendMode(doc::BlendMode mode) { m_blendMode = mode; }
 
   private:
+    Purpose m_purpose;
     render::ExtraType m_type;
     std::unique_ptr<doc::Cel> m_cel;
     doc::ImageRef m_image;

src/app/ui/editor/brush_preview.cpp

@@ -351,6 +351,7 @@ void BrushPreview::show(const gfx::Point& screenPos)
       m_extraCel.reset(new ExtraCel);
 
     m_extraCel->create(
+      ExtraCel::Purpose::BrushPreview,
       tilemapMode,
       document->sprite(),
       extraCelBoundsInCanvas,

src/app/ui/editor/editor.cpp

@@ -705,8 +705,16 @@ void Editor::drawOneSpriteUnclippedRect(ui::Graphics* g, const gfx::Rect& sprite
     ExtraCelRef extraCel = m_document->extraCel();
     if (extraCel &&
         extraCel->type() != render::ExtraType::NONE &&
-        (!m_docView->isPreview() ||
+        // We render the extra cel if:
-         m_docPref.show.brushPreviewInPreview())) {
+        (// 1) it doesn't contains the brush preview (e.g. the user
+         // is transforming the selection),
+         extraCel->purpose() != ExtraCel::Purpose::BrushPreview
+         // 2) we are drawing the brush preview in a regular editor,
+         || !m_docView->isPreview()
+         // 3) we are drawing the brush preview in a preview editor
+         // and preferences (brushPreviewInPreview) says that we
+         // should do that.
+         || m_docPref.show.brushPreviewInPreview())) {
       m_renderEngine->setExtraImage(extraCel->type(),
                                     extraCel->cel(),
                                     extraCel->image(),

src/app/ui/editor/pixels_movement.cpp

@@ -1156,6 +1156,7 @@ void PixelsMovement::redrawExtraImage(Transformation* transformation)
     }
 
     m_extraCel->create(
+      ExtraCel::Purpose::TransformationPreview,
       m_site.tilemapMode(),
       m_document->sprite(),
       bounds,