Add zoom out (related to issue #33)

Before the zoom was handle as a bits shift (scaled = value << zoom),
now the zoom is a fraction (scaled = value * zoom.num / zoom.den).

Changes:
* Add Zoom class to apply/remove zoom factor
* Split merge_zoomed_image template function into
  merge_zoomed_image_scale_down and merge_zoomed_image_scale_up
  to handle the special case where zoom.num/zoom.den < 1.0

Author: dacap

src/app/CMakeLists.txt

@@ -259,4 +259,5 @@ add_library(app-lib
   webserver.cpp
   widget_loader.cpp
   xml_document.cpp
-  xml_exception.cpp)
+  xml_exception.cpp
+  zoom.cpp)

src/app/commands/cmd_move_mask.cpp

@@ -99,13 +99,13 @@ void MoveMaskCommand::onExecute(Context* context)
       pixels = gridBounds.h;
       break;
     case ZoomedPixel:
-      pixels = 1 << current_editor->zoom();
+      pixels = current_editor->zoom().apply(1);
       break;
     case ZoomedTileWidth:
-      pixels = gridBounds.w << current_editor->zoom();
+      pixels = current_editor->zoom().apply(gridBounds.w);
       break;
     case ZoomedTileHeight:
-      pixels = gridBounds.h << current_editor->zoom();
+      pixels = current_editor->zoom().apply(gridBounds.h);
       break;
     case ViewportWidth:
       pixels = vp.h;

src/app/commands/cmd_preview.cpp

@@ -63,7 +63,8 @@ class PreviewWindow : public Window {
     , m_pal(m_sprite->getPalette(editor->frame()))
     , m_index_bg_color(-1)
     , m_doublebuf(Image::create(IMAGE_RGB, ui::display_w(), ui::display_h()))
-    , m_doublesur(she::instance()->createRgbaSurface(ui::display_w(), ui::display_h())) {
+    , m_doublesur(she::instance()->createRgbaSurface(ui::display_w(), ui::display_h()))
+    , m_zoom(editor->zoom()) {
     // Do not use DocumentWriter (do not lock the document) because we
     // will call other sub-commands (e.g. previous frame, next frame,
     // etc.).
@@ -83,7 +84,6 @@ class PreviewWindow : public Window {
     m_oldMousePos = ui::get_mouse_position();
     m_pos.x = -scroll.x + vp.x + editor->offsetX();
     m_pos.y = -scroll.y + vp.y + editor->offsetY();
-    m_zoom = editor->zoom();
 
     setFocusStop(true);
     captureMouse();
@@ -193,14 +193,14 @@ class PreviewWindow : public Window {
       m_render.reset(
         renderEngine.renderSprite(
           0, 0, m_sprite->width(), m_sprite->height(),
-          m_editor->frame(), 0, false, false));
+          m_editor->frame(), Zoom(1, 1), false, false));
     }
 
     int x, y, w, h, u, v;
-    x = m_pos.x + ((m_delta.x >> m_zoom) << m_zoom);
-    y = m_pos.y + ((m_delta.y >> m_zoom) << m_zoom);
-    w = (m_sprite->width()<<m_zoom);
-    h = (m_sprite->height()<<m_zoom);
+    x = m_pos.x + m_zoom.apply(m_zoom.remove(m_delta.x));
+    y = m_pos.y + m_zoom.apply(m_zoom.remove(m_delta.y));
+    w = m_zoom.apply(m_sprite->width());
+    h = m_zoom.apply(m_sprite->height());
 
     if (m_tiled & TILED_X_AXIS) x = SGN(x) * (ABS(x)%w);
     if (m_tiled & TILED_Y_AXIS) y = SGN(y) * (ABS(y)%h);
@@ -243,7 +243,7 @@ class PreviewWindow : public Window {
   gfx::Point m_pos;
   gfx::Point m_oldMousePos;
   gfx::Point m_delta;
-  int m_zoom;
+  Zoom m_zoom;
   int m_index_bg_color;
   base::UniquePtr<Image> m_render;
   base::UniquePtr<Image> m_doublebuf;

src/app/commands/cmd_scroll.cpp

@@ -117,13 +117,13 @@ void ScrollCommand::onExecute(Context* context)
       pixels = gridBounds.h;
       break;
     case ZoomedPixel:
-      pixels = 1 << current_editor->zoom();
+      pixels = current_editor->zoom().apply(1);
       break;
     case ZoomedTileWidth:
-      pixels = gridBounds.w << current_editor->zoom();
+      pixels = current_editor->zoom().apply(gridBounds.w);
       break;
     case ZoomedTileHeight:
-      pixels = gridBounds.h << current_editor->zoom();
+      pixels = current_editor->zoom().apply(gridBounds.h);
       break;
     case ViewportWidth:
       pixels = vp.h;

src/app/commands/cmd_zoom.cpp

@@ -74,25 +74,23 @@ bool ZoomCommand::onEnabled(Context* context)
 
 void ZoomCommand::onExecute(Context* context)
 {
-  int zoom = current_editor->zoom();
+  Zoom zoom = current_editor->zoom();
 
   switch (m_action) {
     case In:
-      if (zoom < 5)
-        ++zoom;
+      zoom.in();
       break;
     case Out:
-      if (zoom > 0)
-        --zoom;
+      zoom.out();
       break;
     case Set:
       switch (m_percentage) {
-        case 3200: zoom = 5; break;
-        case 1600: zoom = 4; break;
-        case 800: zoom = 3; break;
-        case 400: zoom = 2; break;
-        case 200: zoom = 1; break;
-        default: zoom = 0; break;
+        case 3200: zoom = Zoom(32, 1); break;
+        case 1600: zoom = Zoom(16, 1); break;
+        case 800: zoom = Zoom(8, 1); break;
+        case 400: zoom = Zoom(4, 1); break;
+        case 200: zoom = Zoom(2, 1); break;
+        default: zoom = Zoom(1, 1); break;
       }
       break;
   }

src/app/commands/filters/filter_manager_impl.cpp

@@ -257,8 +257,8 @@ void FilterManagerImpl::flush()
           m_x+m_offset_x,
           m_y+m_offset_y+m_row-1)),
       gfx::Size(
-        (m_w << editor->zoom()),
-        (1 << editor->zoom())));
+        editor->zoom().apply(m_w),
+        editor->zoom().apply(1)));
 
     gfx::Region reg1(rect);
     gfx::Region reg2;

src/app/thumbnail_generator.cpp

@@ -85,7 +85,7 @@ class ThumbnailGenerator::Worker {
 
         base::UniquePtr<Image> image(renderEngine.renderSprite(
             0, 0, sprite->width(), sprite->height(),
-            FrameNumber(0), 0, true, false));
+            FrameNumber(0), Zoom(1, 1), true, false));
 
         // Calculate the thumbnail size
         int thumb_w = MAX_THUMBNAIL_SIZE * image->width() / MAX(image->width(), image->height());

src/app/tools/tool_loop.h

@@ -22,6 +22,7 @@
 
 #include "app/settings/selection_mode.h"
 #include "app/tools/trace_policy.h"
+#include "app/zoom.h"
 #include "doc/frame_number.h"
 #include "filters/tiled_mode.h"
 #include "gfx/point.h"
@@ -104,6 +105,9 @@ namespace app {
       // Gets mask X,Y origin coordinates
       virtual gfx::Point getMaskOrigin() = 0;
 
+      // Returns the zoom
+      virtual const Zoom& zoom() = 0;
+
       // Return the mouse button which start the tool-loop. It can be used
       // by some tools that instead of using the primary/secondary color
       // uses the pressed button for different behavior (like selection

src/app/tools/tool_loop_manager.cpp

@@ -213,7 +213,7 @@ void ToolLoopManager::doLoopStep(bool last_step)
 
   // Calculate the area to be updated in all document observers.
   Region& dirty_area = m_toolLoop->getDirtyArea();
-  calculateDirtyArea(m_toolLoop, points_to_interwine, dirty_area);
+  calculateDirtyArea(points_to_interwine, dirty_area);
 
   if (m_toolLoop->getTracePolicy() == TracePolicyLast) {
     Region prev_dirty_area = dirty_area;
@@ -235,7 +235,7 @@ void ToolLoopManager::snapToGrid(Point& point)
   m_toolLoop->getDocumentSettings()->snapToGrid(point);
 }
 
-void ToolLoopManager::calculateDirtyArea(ToolLoop* loop, const Points& points, Region& dirty_area)
+void ToolLoopManager::calculateDirtyArea(const Points& points, Region& dirty_area)
 {
   dirty_area.clear();
 
@@ -245,21 +245,21 @@ void ToolLoopManager::calculateDirtyArea(ToolLoop* loop, const Points& points, R
 
     // Expand the dirty-area with the pen width
     Rect r1, r2;
-    loop->getPointShape()->getModifiedArea(loop, minpt.x, minpt.y, r1);
-    loop->getPointShape()->getModifiedArea(loop, maxpt.x, maxpt.y, r2);
+    m_toolLoop->getPointShape()->getModifiedArea(m_toolLoop, minpt.x, minpt.y, r1);
+    m_toolLoop->getPointShape()->getModifiedArea(m_toolLoop, maxpt.x, maxpt.y, r2);
 
     dirty_area.createUnion(dirty_area, Region(r1.createUnion(r2)));
   }
 
   // Apply offset mode
-  Point offset(loop->getOffset());
+  Point offset(m_toolLoop->getOffset());
   dirty_area.offset(-offset);
 
   // Apply tiled mode
-  TiledMode tiledMode = loop->getDocumentSettings()->getTiledMode();
+  TiledMode tiledMode = m_toolLoop->getDocumentSettings()->getTiledMode();
   if (tiledMode != TILED_NONE) {
-    int w = loop->sprite()->width();
-    int h = loop->sprite()->height();
+    int w = m_toolLoop->sprite()->width();
+    int h = m_toolLoop->sprite()->height();
     Region sprite_area(Rect(0, 0, w, h));
     Region outside;
     outside.createSubtraction(dirty_area, sprite_area);
@@ -312,6 +312,11 @@ void ToolLoopManager::calculateMinMax(const Points& points, Point& minpt, Point&
     maxpt.x = MAX(maxpt.x, points[c].x);
     maxpt.y = MAX(maxpt.y, points[c].y);
   }
+
+  if (m_toolLoop->zoom().scale() < 1.0) {
+    maxpt.x += m_toolLoop->zoom().remove(1);
+    maxpt.y += m_toolLoop->zoom().remove(1);
+  }
 }
 
 } // namespace tools  

src/app/tools/tool_loop_manager.h

@@ -103,13 +103,13 @@ namespace app {
       void doLoopStep(bool last_step);
       void snapToGrid(gfx::Point& point);
 
-      static void calculateDirtyArea(ToolLoop* loop,
-                                     const Points& points,
-                                     gfx::Region& dirty_area);
+      void calculateDirtyArea(
+        const Points& points,
+        gfx::Region& dirty_area);
 
-      static void calculateMinMax(const Points& points,
-                                  gfx::Point& minpt,
-                                  gfx::Point& maxpt);
+      void calculateMinMax(const Points& points,
+        gfx::Point& minpt,
+        gfx::Point& maxpt);
 
       ToolLoop* m_toolLoop;
       Points m_points;