From 5ccf414183e9ebc7f16d2acc5ce7a44bce1aad80 Mon Sep 17 00:00:00 2001
From: David Capello <david@igarastudio.com>
Date: Mon, 21 Feb 2022 15:30:09 -0300
Subject: [PATCH] Add options to change the downsampling algorithm (fix #3183)

Also we've restored the default algorithm to bilinear + mipmapping,
which was the default on the Aseprite before we switched to Skia m96.
This was requested by some users.
---
 data/pref.xml                |  7 +++
 laf                          |  2 +-
 src/app/script/values.cpp    |  3 +-
 src/app/ui/context_bar.cpp   | 89 ++++++++++++++++++++++++++++++++----
 src/app/ui/context_bar.h     |  6 ++-
 src/app/ui/editor/editor.cpp | 67 +++++++++++++++++++++++----
 src/app/ui/editor/editor.h   |  3 ++
 src/ui/graphics.cpp          | 22 ++++++++-
 src/ui/graphics.h            |  8 +++-
 9 files changed, 183 insertions(+), 24 deletions(-)

diff --git a/data/pref.xml b/data/pref.xml
index 5185574e8..26f4796d6 100644
--- a/data/pref.xml
+++ b/data/pref.xml
@@ -127,6 +127,12 @@
       <value id="YES" value="1" />
       <value id="NO" value="2" />
     </enum>
+    <enum id="Downsampling">
+      <value id="NEAREST" value="0" />
+      <value id="BILINEAR" value="1" />
+      <value id="BILINEAR_MIPMAP" value="2" />
+      <value id="TRILINEAR_MIPMAP" value="3" />
+    </enum>
   </types>
 
   <global>
@@ -176,6 +182,7 @@
            some performance issue rendering huge sprites with small
            zoom levels -->
       <option id="auto_fit" type="bool" default="false" />
+      <option id="downsampling" type="Downsampling" default="Downsampling::BILINEAR_MIPMAP" />
     </section>
     <section id="timeline">
       <option id="keep_selection" type="bool" default="false" />
diff --git a/laf b/laf
index f473cc6f8..7c819791e 160000
--- a/laf
+++ b/laf
@@ -1 +1 @@
-Subproject commit f473cc6f8c68629ef0e8c480afbba5659ef5de75
+Subproject commit 7c819791e50116b54e0666dbf96822e0993d1d1f
diff --git a/src/app/script/values.cpp b/src/app/script/values.cpp
index ddf14855a..490b33c81 100644
--- a/src/app/script/values.cpp
+++ b/src/app/script/values.cpp
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019-2021  Igara Studio S.A.
+// Copyright (C) 2019-2022  Igara Studio S.A.
 //
 // This program is distributed under the terms of
 // the End-User License Agreement for Aseprite.
@@ -165,6 +165,7 @@ FOR_ENUM(app::gen::BgType)
 FOR_ENUM(app::gen::BrushPreview)
 FOR_ENUM(app::gen::BrushType)
 FOR_ENUM(app::gen::ColorProfileBehavior)
+FOR_ENUM(app::gen::Downsampling)
 FOR_ENUM(app::gen::EyedropperChannel)
 FOR_ENUM(app::gen::EyedropperSample)
 FOR_ENUM(app::gen::FillReferTo)
diff --git a/src/app/ui/context_bar.cpp b/src/app/ui/context_bar.cpp
index faa854f34..9c4775591 100644
--- a/src/app/ui/context_bar.cpp
+++ b/src/app/ui/context_bar.cpp
@@ -56,6 +56,7 @@
 #include "doc/selected_objects.h"
 #include "doc/slice.h"
 #include "obs/connection.h"
+#include "os/sampling.h"
 #include "os/surface.h"
 #include "os/system.h"
 #include "render/dithering.h"
@@ -133,6 +134,49 @@ private:
   }
 };
 
+class ContextBar::SamplingOptions : public HBox {
+public:
+  class Item : public ListItem {
+  public:
+    Item(const char* label,
+         const gen::Downsampling sampling)
+      : ListItem(label)
+      , m_sampling(sampling) {
+    }
+    const gen::Downsampling& sampling() const { return m_sampling; }
+  private:
+    gen::Downsampling m_sampling;
+  };
+
+  SamplingOptions()
+    : m_downsamplingLabel("Downsampling:")
+  {
+    addChild(&m_downsamplingLabel);
+    addChild(&m_downsampling);
+
+    m_downsampling.addItem(new Item("Nearest", gen::Downsampling::NEAREST));
+    m_downsampling.addItem(new Item("Bilinear", gen::Downsampling::BILINEAR));
+    m_downsampling.addItem(new Item("Bilinear mipmapping", gen::Downsampling::BILINEAR_MIPMAP));
+    m_downsampling.addItem(new Item("Trilinear mipmapping", gen::Downsampling::TRILINEAR_MIPMAP));
+    m_downsampling.setSelectedItemIndex(
+      (int)Preferences::instance().editor.downsampling());
+
+    m_downsampling.Change.connect([this]{ onDownsamplingChange(); });
+  }
+
+private:
+
+  void onDownsamplingChange() {
+    if (auto item = dynamic_cast<Item*>(m_downsampling.getSelectedItem())) {
+      Preferences::instance().editor.downsampling(
+        item->sampling());
+    }
+  }
+
+  Label m_downsamplingLabel;
+  ComboBox m_downsampling;
+};
+
 class ContextBar::BrushBackField : public ButtonSet {
 public:
   BrushBackField()
@@ -1537,6 +1581,7 @@ ContextBar::ContextBar(TooltipManager* tooltipManager,
   m_selectionOptionsBox->addChild(m_rotAlgo = new RotAlgorithmField());
 
   addChild(m_zoomButtons = new ZoomButtons);
+  addChild(m_samplingOptions = new SamplingOptions);
 
   addChild(m_brushBack = new BrushBackField);
   addChild(m_brushType = new BrushTypeField(this));
@@ -1843,13 +1888,6 @@ void ContextBar::updateForTool(tools::Tool* tool)
     (activeBrush()->type() == kSquareBrushType ||
      activeBrush()->type() == kLineBrushType);
 
-  // True if the current tool is eyedropper.
-  const bool needZoomButtons = tool &&
-    (tool->getInk(0)->isZoom() ||
-     tool->getInk(1)->isZoom() ||
-     tool->getInk(0)->isScrollMovement() ||
-     tool->getInk(1)->isScrollMovement());
-
   // True if the current tool is eyedropper.
   const bool isEyedropper = tool &&
     (tool->getInk(0)->isEyedropper() ||
@@ -1902,7 +1940,7 @@ void ContextBar::updateForTool(tools::Tool* tool)
   const bool supportDynamics = (!hasImageBrush);
 
   // Show/Hide fields
-  m_zoomButtons->setVisible(needZoomButtons);
+  m_zoomButtons->setVisible(needZoomButtons(tool));
   m_brushBack->setVisible(supportOpacity && hasImageBrush && !withDithering);
   m_brushType->setVisible(supportOpacity && (!isFloodfill || (isFloodfill && hasImageBrush && !withDithering)));
   m_brushSize->setVisible(supportOpacity && !isFloodfill && !hasImageBrush);
@@ -1940,7 +1978,11 @@ void ContextBar::updateForTool(tools::Tool* tool)
   if (updateShade)
     m_inkShades->updateShadeFromColorBarPicks();
 
-  layout();
+  if (!updateSamplingVisibility(tool)) {
+    // updateSamplingVisibility() returns false if it doesn't layout()
+    // the ContextBar.
+    layout();
+  }
 }
 
 void ContextBar::updateForMovingPixels()
@@ -1980,6 +2022,26 @@ void ContextBar::updateToolLoopModifiersIndicators(tools::ToolLoopModifiers modi
   m_selectionMode->setSelectionMode(mode);
 }
 
+bool ContextBar::updateSamplingVisibility(tools::Tool* tool)
+{
+  if (!tool)
+    tool = App::instance()->activeTool();
+
+  const bool newVisibility =
+    needZoomButtons(tool) &&
+    current_editor &&
+    (current_editor->projection().scaleX() < 1.0 ||
+     current_editor->projection().scaleY() < 1.0) &&
+    current_editor->isUsingNewRenderEngine();
+
+  if (newVisibility == m_samplingOptions->hasFlags(HIDDEN)) {
+    m_samplingOptions->setVisible(newVisibility);
+    layout();
+    return true;
+  }
+  return false;
+}
+
 void ContextBar::updateAutoSelectLayer(bool state)
 {
   m_autoSelectLayer->setSelected(state);
@@ -2285,4 +2347,13 @@ void ContextBar::showDynamics()
     m_dynamics->switchPopup();
 }
 
+bool ContextBar::needZoomButtons(tools::Tool* tool) const
+{
+  return tool &&
+    (tool->getInk(0)->isZoom() ||
+     tool->getInk(1)->isZoom() ||
+     tool->getInk(0)->isScrollMovement() ||
+     tool->getInk(1)->isScrollMovement());
+}
+
 } // namespace app
diff --git a/src/app/ui/context_bar.h b/src/app/ui/context_bar.h
index 254d9ef9b..c62e76bb8 100644
--- a/src/app/ui/context_bar.h
+++ b/src/app/ui/context_bar.h
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2018-2020  Igara Studio S.A.
+// Copyright (C) 2018-2022  Igara Studio S.A.
 // Copyright (C) 2001-2017  David Capello
 //
 // This program is distributed under the terms of
@@ -67,6 +67,7 @@ namespace app {
     void updateForMovingPixels();
     void updateForSelectingBox(const std::string& text);
     void updateToolLoopModifiersIndicators(tools::ToolLoopModifiers modifiers);
+    bool updateSamplingVisibility(tools::Tool* tool = nullptr);
     void updateAutoSelectLayer(bool state);
     bool isAutoSelectLayer() const;
 
@@ -129,8 +130,10 @@ namespace app {
     void registerCommands();
     void showBrushes();
     void showDynamics();
+    bool needZoomButtons(tools::Tool* tool) const;
 
     class ZoomButtons;
+    class SamplingOptions;
     class BrushBackField;
     class BrushTypeField;
     class BrushAngleField;
@@ -158,6 +161,7 @@ namespace app {
     class SliceFields;
 
     ZoomButtons* m_zoomButtons;
+    SamplingOptions* m_samplingOptions;
     BrushBackField* m_brushBack;
     BrushTypeField* m_brushType;
     BrushAngleField* m_brushAngle;
diff --git a/src/app/ui/editor/editor.cpp b/src/app/ui/editor/editor.cpp
index 1a98de703..7c9f97cf1 100644
--- a/src/app/ui/editor/editor.cpp
+++ b/src/app/ui/editor/editor.cpp
@@ -60,6 +60,7 @@
 #include "doc/mask_boundaries.h"
 #include "doc/slice.h"
 #include "os/color_space.h"
+#include "os/sampling.h"
 #include "os/surface.h"
 #include "os/system.h"
 #include "os/window.h"
@@ -174,6 +175,10 @@ Editor::Editor(Doc* document, EditorFlags flags)
     Preferences::instance().colorBar.fgColor.AfterChange.connect(
       [this]{ onFgColorChange(); });
 
+  m_samplingChangeConn =
+    Preferences::instance().editor.downsampling.AfterChange.connect(
+      [this]{ onSamplingChange(); });
+
   m_contextBarBrushChangeConn =
     App::instance()->contextBar()->BrushChange.connect(
       [this]{ onContextBarBrushChange(); });
@@ -239,6 +244,18 @@ bool Editor::isActive() const
   return (current_editor == this);
 }
 
+bool Editor::isUsingNewRenderEngine() const
+{
+  ASSERT(m_sprite);
+  return
+    (Preferences::instance().experimental.newRenderEngine()
+     // Reference layers + zoom > 100% need the old render engine for
+     // sub-pixel rendering.
+     && (!m_sprite->hasVisibleReferenceLayers()
+         || (m_proj.scaleX() <= 1.0
+             && m_proj.scaleY() <= 1.0)));
+}
+
 // static
 WidgetType Editor::Type()
 {
@@ -410,6 +427,9 @@ void Editor::setZoom(const render::Zoom& zoom)
   if (m_proj.zoom() != zoom) {
     m_proj.setZoom(zoom);
     notifyZoomChanged();
+
+    if (isActive())
+      App::instance()->contextBar()->updateSamplingVisibility();
   }
   else {
     // Just copy the zoom as the internal "Zoom::m_internalScale"
@@ -582,13 +602,8 @@ void Editor::drawOneSpriteUnclippedRect(ui::Graphics* g, const gfx::Rect& sprite
     return;
 
   // rc2 is the rectangle used to create a temporal rendered image of the sprite
-  const bool newEngine =
-    (Preferences::instance().experimental.newRenderEngine()
-     // Reference layers + zoom > 100% need the old render engine for
-     // sub-pixel rendering.
-     && (!m_sprite->hasVisibleReferenceLayers()
-         || (m_proj.scaleX() <= 1.0
-             && m_proj.scaleY() <= 1.0)));
+  const auto& pref = Preferences::instance();
+  const bool newEngine = isUsingNewRenderEngine();
   gfx::Rect rc2;
   if (newEngine) {
     rc2 = expose;               // New engine, exposed rectangle (without zoom)
@@ -614,11 +629,11 @@ void Editor::drawOneSpriteUnclippedRect(ui::Graphics* g, const gfx::Rect& sprite
     rendered.reset(Image::create(IMAGE_RGB, rc2.w, rc2.h,
                                  m_renderEngine->getRenderImageBuffer()));
 
-    m_renderEngine->setNewBlendMethod(Preferences::instance().experimental.newBlend());
+    m_renderEngine->setNewBlendMethod(pref.experimental.newBlend());
     m_renderEngine->setRefLayersVisiblity(true);
     m_renderEngine->setSelectedLayer(m_layer);
     if (m_flags & Editor::kUseNonactiveLayersOpacityWhenEnabled)
-      m_renderEngine->setNonactiveLayersOpacity(Preferences::instance().experimental.nonactiveLayersOpacity());
+      m_renderEngine->setNonactiveLayersOpacity(pref.experimental.nonactiveLayersOpacity());
     else
       m_renderEngine->setNonactiveLayersOpacity(255);
     m_renderEngine->setProjection(
@@ -710,7 +725,30 @@ void Editor::drawOneSpriteUnclippedRect(ui::Graphics* g, const gfx::Rect& sprite
                                tmp.get(), 0, 0, 0, 0, rc2.w, rc2.h);
 
       if (newEngine) {
-        g->drawSurface(tmp.get(), gfx::Rect(0, 0, rc2.w, rc2.h), dest);
+        os::Sampling sampling;
+        if (m_proj.scaleX() < 1.0) {
+          switch (pref.editor.downsampling()) {
+            case gen::Downsampling::NEAREST:
+              sampling = os::Sampling(os::Sampling::Filter::Nearest);
+              break;
+            case gen::Downsampling::BILINEAR:
+              sampling = os::Sampling(os::Sampling::Filter::Linear);
+              break;
+            case gen::Downsampling::BILINEAR_MIPMAP:
+              sampling = os::Sampling(os::Sampling::Filter::Linear,
+                                      os::Sampling::Mipmap::Nearest);
+              break;
+            case gen::Downsampling::TRILINEAR_MIPMAP:
+              sampling = os::Sampling(os::Sampling::Filter::Linear,
+                                      os::Sampling::Mipmap::Linear);
+              break;
+          }
+        }
+
+        g->drawSurface(tmp.get(),
+                       gfx::Rect(0, 0, rc2.w, rc2.h),
+                       dest,
+                       sampling);
       }
       else {
         g->blit(tmp.get(), 0, 0, dest.x, dest.y, dest.w, dest.h);
@@ -2112,6 +2150,15 @@ void Editor::onActiveToolChange(tools::Tool* tool)
   }
 }
 
+void Editor::onSamplingChange()
+{
+  if (m_proj.scaleX() < 1.0 &&
+      m_proj.scaleY() < 1.0 &&
+      isUsingNewRenderEngine()) {
+    invalidate();
+  }
+}
+
 void Editor::onFgColorChange()
 {
   m_brushPreview.redraw();
diff --git a/src/app/ui/editor/editor.h b/src/app/ui/editor/editor.h
index 8b8f0a8bb..c429caa04 100644
--- a/src/app/ui/editor/editor.h
+++ b/src/app/ui/editor/editor.h
@@ -108,6 +108,7 @@ namespace app {
     static void destroyEditorSharedInternals();
 
     bool isActive() const;
+    bool isUsingNewRenderEngine() const;
 
     DocView* getDocView() { return m_docView; }
     void setDocView(DocView* docView) { m_docView = docView; }
@@ -311,6 +312,7 @@ namespace app {
     void onResize(ui::ResizeEvent& ev) override;
     void onPaint(ui::PaintEvent& ev) override;
     void onInvalidateRegion(const gfx::Region& region) override;
+    void onSamplingChange();
     void onFgColorChange();
     void onContextBarBrushChange();
     void onTiledModeBeforeChange();
@@ -405,6 +407,7 @@ namespace app {
     ui::Timer m_antsTimer;
     int m_antsOffset;
 
+    obs::scoped_connection m_samplingChangeConn;
     obs::scoped_connection m_fgColorChangeConn;
     obs::scoped_connection m_contextBarBrushChangeConn;
     obs::scoped_connection m_showExtrasConn;
diff --git a/src/ui/graphics.cpp b/src/ui/graphics.cpp
index 44eb97de7..3efd2deee 100644
--- a/src/ui/graphics.cpp
+++ b/src/ui/graphics.cpp
@@ -1,5 +1,5 @@
 // Aseprite UI Library
-// Copyright (C) 2019-2021  Igara Studio S.A.
+// Copyright (C) 2019-2022  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -21,6 +21,7 @@
 #include "gfx/size.h"
 #include "os/draw_text.h"
 #include "os/font.h"
+#include "os/sampling.h"
 #include "os/surface.h"
 #include "os/system.h"
 #include "os/window.h"
@@ -260,6 +261,25 @@ void Graphics::drawSurface(os::Surface* surface,
     gfx::Rect(dstRect).offset(m_dx, m_dy));
 }
 
+void Graphics::drawSurface(os::Surface* surface,
+                           const gfx::Rect& srcRect,
+                           const gfx::Rect& dstRect,
+                           const os::Sampling& sampling,
+                           const ui::Paint* paint)
+{
+  dirty(gfx::Rect(m_dx+dstRect.x, m_dy+dstRect.y,
+                  dstRect.w, dstRect.h));
+
+  os::SurfaceLock lockSrc(surface);
+  os::SurfaceLock lockDst(m_surface.get());
+  m_surface->drawSurface(
+    surface,
+    srcRect,
+    gfx::Rect(dstRect).offset(m_dx, m_dy),
+    sampling,
+    paint);
+}
+
 void Graphics::drawRgbaSurface(os::Surface* surface, int x, int y)
 {
   dirty(gfx::Rect(m_dx+x, m_dy+y, surface->width(), surface->height()));
diff --git a/src/ui/graphics.h b/src/ui/graphics.h
index d0db15fb9..ebdc90ad4 100644
--- a/src/ui/graphics.h
+++ b/src/ui/graphics.h
@@ -1,5 +1,5 @@
 // Aseprite UI Library
-// Copyright (C) 2019-2020  Igara Studio S.A.
+// Copyright (C) 2019-2022  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -30,6 +30,7 @@ namespace gfx {
 
 namespace os {
   class DrawTextDelegate;
+  class Sampling;
 }
 
 namespace ui {
@@ -89,6 +90,11 @@ namespace ui {
     void drawSurface(os::Surface* surface,
                      const gfx::Rect& srcRect,
                      const gfx::Rect& dstRect);
+    void drawSurface(os::Surface* surface,
+                     const gfx::Rect& srcRect,
+                     const gfx::Rect& dstRect,
+                     const os::Sampling& sampling,
+                     const ui::Paint* paint = nullptr);
     void drawRgbaSurface(os::Surface* surface, int x, int y);
     void drawRgbaSurface(os::Surface* surface, int srcx, int srcy, int dstx, int dsty, int w, int h);
     void drawRgbaSurface(os::Surface* surface,