lua: Add Image:isEqual()

src/app/script/image_class.cpp

@@ -176,6 +176,16 @@ int Image_getPixel(lua_State* L)
   return 1;
 }
 
+int Image_isEqual(lua_State* L)
+{
+  auto objA = get_obj<ImageObj>(L, 1);
+  auto objB = get_obj<ImageObj>(L, 2);
+  bool res = doc::is_same_image(objA->image.get(),
+                                objB->image.get());
+  lua_pushboolean(L, res);
+  return 1;
+}
+
 int Image_get_width(lua_State* L)
 {
   const auto obj = get_obj<ImageObj>(L, 1);
@@ -211,6 +221,7 @@ const luaL_Reg Image_methods[] = {
   { "putImage", Image_putImage },
   { "putSprite", Image_putSprite },
   { "pixels", Image_pixels },
+  { "isEqual", Image_isEqual },
   { "__gc", Image_gc },
   { nullptr, nullptr }
 };

src/app/script/selection_class.cpp

@@ -64,7 +64,7 @@ int Selection_eq(lua_State* L)
   const bool result =
     (a->mask->isEmpty() && b->mask->isEmpty()) ||
     (!a->mask->isEmpty() && !b->mask->isEmpty() &&
-     count_diff_between_images(a->mask->bitmap(), b->mask->bitmap()) == 0);
+     is_same_image(a->mask->bitmap(), b->mask->bitmap()));
   lua_pushboolean(L, result);
   return 1;
 }

src/doc/image_traits.h

@@ -10,6 +10,7 @@
 #pragma once
 
 #include "doc/blend_funcs.h"
+#include "doc/color.h"
 #include "doc/color_mode.h"
 #include "doc/pixel_format.h"
 
@@ -41,6 +42,19 @@ namespace doc {
     static inline BlendFunc get_blender(BlendMode blend_mode) {
       return get_rgba_blender(blend_mode);
     }
+
+    static inline bool same_color(const pixel_t a, const pixel_t b) {
+      if (rgba_geta(a) == 0) {
+        if (rgba_geta(b) == 0)
+          return true;
+        else
+          return false;
+      }
+      else if (rgba_geta(b) == 0)
+        return false;
+      else
+        return a == b;
+    }
   };
 
   struct GrayscaleTraits {
@@ -69,6 +83,19 @@ namespace doc {
     static inline BlendFunc get_blender(BlendMode blend_mode) {
       return get_graya_blender(blend_mode);
     }
+
+    static inline bool same_color(const pixel_t a, const pixel_t b) {
+      if (graya_geta(a) == 0) {
+        if (graya_geta(b) == 0)
+          return true;
+        else
+          return false;
+      }
+      else if (graya_geta(b) == 0)
+        return false;
+      else
+        return a == b;
+    }
   };
 
   struct IndexedTraits {
@@ -97,6 +124,10 @@ namespace doc {
     static inline BlendFunc get_blender(BlendMode blend_mode) {
       return get_indexed_blender(blend_mode);
     }
+
+    static inline bool same_color(const pixel_t a, const pixel_t b) {
+      return a == b;
+    }
   };
 
   struct BitmapTraits {
@@ -121,6 +152,10 @@ namespace doc {
     static inline int getRowStrideBytes(int pixels_per_row) {
       return ((pixels_per_row+7) / 8);
     }
+
+    static inline bool same_color(const pixel_t a, const pixel_t b) {
+      return a == b;
+    }
   };
 
 } // namespace doc

src/doc/primitives.cpp

@@ -319,15 +319,31 @@ int count_diff_between_images_templ(const Image* i1, const Image* i2)
   for (it1 = bits1.begin(), end1 = bits1.end(),
        it2 = bits2.begin(), end2 = bits2.end();
        it1 != end1 && it2 != end2; ++it1, ++it2) {
-    if (*it1 != *it2)
+    if (!ImageTraits::same_color(*it1, *it2))
       diff++;
   }
-
   ASSERT(it1 == end1);
   ASSERT(it2 == end2);
   return diff;
 }
 
+template<typename ImageTraits>
+int is_same_image_templ(const Image* i1, const Image* i2)
+{
+  const LockImageBits<ImageTraits> bits1(i1);
+  const LockImageBits<ImageTraits> bits2(i2);
+  typename LockImageBits<ImageTraits>::const_iterator it1, it2, end1, end2;
+  for (it1 = bits1.begin(), end1 = bits1.end(),
+       it2 = bits2.begin(), end2 = bits2.end();
+       it1 != end1 && it2 != end2; ++it1, ++it2) {
+    if (!ImageTraits::same_color(*it1, *it2))
+      return false;
+  }
+  ASSERT(it1 == end1);
+  ASSERT(it2 == end2);
+  return true;
+}
+
 } // anonymous namespace
 
 bool is_plain_image(const Image* img, color_t c)
@@ -367,6 +383,24 @@ int count_diff_between_images(const Image* i1, const Image* i2)
   return -1;
 }
 
+bool is_same_image(const Image* i1, const Image* i2)
+{
+  if ((i1->pixelFormat() != i2->pixelFormat()) ||
+      (i1->width() != i2->width()) ||
+      (i1->height() != i2->height()))
+    return false;
+
+  switch (i1->pixelFormat()) {
+    case IMAGE_RGB:       return is_same_image_templ<RgbTraits>(i1, i2);
+    case IMAGE_GRAYSCALE: return is_same_image_templ<GrayscaleTraits>(i1, i2);
+    case IMAGE_INDEXED:   return is_same_image_templ<IndexedTraits>(i1, i2);
+    case IMAGE_BITMAP:    return is_same_image_templ<BitmapTraits>(i1, i2);
+  }
+
+  ASSERT(false);
+  return false;
+}
+
 void remap_image(Image* image, const Remap& remap)
 {
   ASSERT(image->pixelFormat() == IMAGE_INDEXED);

src/doc/primitives.h

@@ -44,6 +44,7 @@ namespace doc {
   bool is_empty_image(const Image* img);
 
   int count_diff_between_images(const Image* i1, const Image* i2);
+  bool is_same_image(const Image* i1, const Image* i2);
 
   void remap_image(Image* image, const Remap& remap);