diff --git a/SourceX/DiabloUI/art_draw.cpp b/SourceX/DiabloUI/art_draw.cpp
index 6c0a64812..6c8e06b21 100644
--- a/SourceX/DiabloUI/art_draw.cpp
+++ b/SourceX/DiabloUI/art_draw.cpp
@@ -6,17 +6,16 @@ namespace dvl {
 extern SDL_Surface *pal_surface;
 extern unsigned int pal_surface_palette_version;
 
-void DrawArt(int screenX, int screenY, Art *art, int nFrame,
-    decltype(SDL_Rect().w) srcW, decltype(SDL_Rect().h) srcH)
+void DrawArt(int screenX, int screenY, Art *art, int nFrame, Uint16 srcW, Uint16 srcH)
 {
 	if (screenY >= SCREEN_HEIGHT || screenX >= SCREEN_WIDTH || art->surface == NULL)
 		return;
 
 	SDL_Rect src_rect = {
 		0,
-		static_cast<decltype(SDL_Rect().y)>(nFrame * art->h()),
-		static_cast<decltype(SDL_Rect().w)>(art->w()),
-		static_cast<decltype(SDL_Rect().h)>(art->h())
+		static_cast<Sint16>(nFrame * art->h()),
+		static_cast<Uint16>(art->w()),
+		static_cast<Uint16>(art->h())
 	};
 	ScaleOutputRect(&src_rect);
 
diff --git a/SourceX/DiabloUI/art_draw.h b/SourceX/DiabloUI/art_draw.h
index 03c14cc46..f1de5ec14 100644
--- a/SourceX/DiabloUI/art_draw.h
+++ b/SourceX/DiabloUI/art_draw.h
@@ -6,8 +6,7 @@
 
 namespace dvl {
 
-void DrawArt(int screenX, int screenY, Art *art, int nFrame = 0,
-    decltype(SDL_Rect().w) srcW = 0, decltype(SDL_Rect().h) srcH = 0);
+void DrawArt(int screenX, int screenY, Art *art, int nFrame = 0, Uint16 srcW = 0, Uint16 srcH = 0);
 
 void DrawAnimatedArt(Art *art, int screenX, int screenY);
 
diff --git a/SourceX/DiabloUI/button.h b/SourceX/DiabloUI/button.h
index 58ae3c821..e1412b7c8 100644
--- a/SourceX/DiabloUI/button.h
+++ b/SourceX/DiabloUI/button.h
@@ -11,11 +11,11 @@ inline void UnloadSmlButtonArt()
 {
 	SmlButton.Unload();
 }
-constexpr decltype(SDL_Rect().w) SML_BUTTON_WIDTH = 110;
-constexpr decltype(SDL_Rect().h) SML_BUTTON_HEIGHT = 28;
+const Uint16 SML_BUTTON_WIDTH = 110;
+const Uint16 SML_BUTTON_HEIGHT = 28;
 
 constexpr UiButton MakeSmlButton(
-    const char *text, void (*action)(), decltype(SDL_Rect().x) x, decltype(SDL_Rect().y) y, int flags = 0)
+    const char *text, void (*action)(), Sint16 x, Sint16 y, int flags = 0)
 {
 	return UiButton(
 	    &SmlButton,
diff --git a/SourceX/DiabloUI/credits.cpp b/SourceX/DiabloUI/credits.cpp
index 974a80c16..b1265ad3e 100644
--- a/SourceX/DiabloUI/credits.cpp
+++ b/SourceX/DiabloUI/credits.cpp
@@ -47,7 +47,7 @@ struct CachedLine {
 
 	std::size_t index;
 	SurfacePtr surface;
-	decltype(pal_surface_palette_version) palette_version;
+	unsigned int palette_version;
 };
 
 SurfacePtr RenderText(const char *text, SDL_Color color)
@@ -197,7 +197,7 @@ public:
 private:
 	LinesBuffer lines_;
 	bool finished_;
-	decltype(SDL_GetTicks()) ticks_begin_;
+	Uint32 ticks_begin_;
 	int prev_offset_y_;
 };
 
@@ -234,7 +234,7 @@ void CreditsRenderer::Render()
 	SDL_SetClipRect(GetOutputSurface(), &viewport);
 
 	// We use unscaled coordinates for calculation throughout.
-	decltype(SDL_Rect().y) dest_y = VIEWPORT.y - (offset_y - lines_begin * LINE_H);
+	Sint16 dest_y = VIEWPORT.y - (offset_y - lines_begin * LINE_H);
 	for (std::size_t i = 0; i < lines_.size(); ++i, dest_y += LINE_H) {
 		auto &line = lines_[i];
 		if (line.surface == NULL)
@@ -244,7 +244,7 @@ void CreditsRenderer::Render()
 		if (line.palette_version != pal_surface_palette_version)
 			line = PrepareLine(line.index);
 
-		decltype(SDL_Rect().x) dest_x = PANEL_LEFT + VIEWPORT.x + 31;
+		Sint16 dest_x = PANEL_LEFT + VIEWPORT.x + 31;
 		if (CREDITS_LINES[line.index][0] == '\t')
 			dest_x += 40;
 
diff --git a/SourceX/DiabloUI/progress.cpp b/SourceX/DiabloUI/progress.cpp
index 85463ee57..1099ac89f 100644
--- a/SourceX/DiabloUI/progress.cpp
+++ b/SourceX/DiabloUI/progress.cpp
@@ -81,8 +81,8 @@ void progress_Render(BYTE progress)
 
 	if (msgSurface) {
 		SDL_Rect dsc_rect = {
-			static_cast<decltype(SDL_Rect().x)>(x + 50),
-			static_cast<decltype(SDL_Rect().y)>(y + 8),
+			static_cast<Sint16>(x + 50),
+			static_cast<Sint16>(y + 8),
 			msgSurface->w,
 			msgSurface->h
 		};
diff --git a/SourceX/DiabloUI/scrollbar.h b/SourceX/DiabloUI/scrollbar.h
index 76a479b14..c5f1a3fd6 100644
--- a/SourceX/DiabloUI/scrollbar.h
+++ b/SourceX/DiabloUI/scrollbar.h
@@ -6,7 +6,7 @@
 namespace dvl {
 
 extern Art ArtScrollBarBackground;
-const decltype(SDL_Rect().w) SCROLLBAR_BG_WIDTH = 25;
+const Uint16 SCROLLBAR_BG_WIDTH = 25;
 
 extern Art ArtScrollBarArrow;
 enum class ScrollBarArrowFrame {
@@ -17,7 +17,7 @@ enum class ScrollBarArrowFrame {
 };
 
 extern Art ArtScrollBarThumb;
-const decltype(SDL_Rect().w) SCROLLBAR_ARROW_WIDTH = 25;
+const Uint16 SCROLLBAR_ARROW_WIDTH = 25;
 
 inline SDL_Rect UpArrowRect(const UiScrollBar &sb)
 {
@@ -25,7 +25,7 @@ inline SDL_Rect UpArrowRect(const UiScrollBar &sb)
 		sb.rect.x,
 		sb.rect.y,
 		SCROLLBAR_ARROW_WIDTH,
-		static_cast<decltype(SDL_Rect().h)>(sb.arrow->h()),
+		static_cast<Uint16>(sb.arrow->h()),
 	};
 }
 
@@ -33,13 +33,13 @@ inline SDL_Rect DownArrowRect(const UiScrollBar &sb)
 {
 	return {
 		sb.rect.x,
-		static_cast<decltype(SDL_Rect().y)>(sb.rect.y + sb.rect.h - sb.arrow->h()),
+		static_cast<Sint16>(sb.rect.y + sb.rect.h) - sb.arrow->h(),
 		SCROLLBAR_ARROW_WIDTH,
-		static_cast<decltype(SDL_Rect().h)>(sb.arrow->h()),
+		static_cast<Uint16>(sb.arrow->h()),
 	};
 }
 
-inline decltype(SDL_Rect().h) BarHeight(const UiScrollBar &sb)
+inline Uint16 BarHeight(const UiScrollBar &sb)
 {
 	return sb.rect.h - 2 * sb.arrow->h();
 }
@@ -48,7 +48,7 @@ inline SDL_Rect BarRect(const UiScrollBar &sb)
 {
 	return {
 		sb.rect.x,
-		static_cast<decltype(SDL_Rect().y)>(sb.rect.y + sb.arrow->h()),
+		static_cast<Sint16>(sb.rect.y + sb.arrow->h()),
 		SCROLLBAR_BG_WIDTH,
 		BarHeight(sb),
 	};
@@ -60,10 +60,10 @@ inline SDL_Rect ThumbRect(const UiScrollBar &sb, std::size_t selected_index, std
 	const int thumb_max_y = BarHeight(sb) - sb.thumb->h();
 	const int thumb_y = (selected_index * thumb_max_y / (num_items - 1));
 	return {
-		static_cast<decltype(SDL_Rect().x)>(sb.rect.x + THUMB_OFFSET_X),
-		static_cast<decltype(SDL_Rect().y)>(sb.rect.y + sb.arrow->h() + thumb_y),
-		static_cast<decltype(SDL_Rect().w)>(sb.rect.w - THUMB_OFFSET_X),
-		static_cast<decltype(SDL_Rect().h)>(sb.thumb->h()),
+		static_cast<Sint16>(sb.rect.x + THUMB_OFFSET_X),
+		static_cast<Sint16>(sb.rect.y + sb.arrow->h() + thumb_y),
+		static_cast<Uint16>(sb.rect.w - THUMB_OFFSET_X),
+		static_cast<Uint16>(sb.thumb->h()),
 	};
 }
 
diff --git a/SourceX/DiabloUI/ttf_render_wrapped.cpp b/SourceX/DiabloUI/ttf_render_wrapped.cpp
index a8891a6e8..18351ce27 100644
--- a/SourceX/DiabloUI/ttf_render_wrapped.cpp
+++ b/SourceX/DiabloUI/ttf_render_wrapped.cpp
@@ -149,8 +149,8 @@ SDL_Surface *RenderUTF8_Solid_Wrapped(TTF_Font *font, const char *text, SDL_Colo
 			SDL_stack_free(str);
 			return NULL;
 		}
-		dest.w = static_cast<decltype(SDL_Rect().w)>(tmp->w);
-		dest.h = static_cast<decltype(SDL_Rect().h)>(tmp->h);
+		dest.w = static_cast<Uint16>(tmp->w);
+		dest.h = static_cast<Uint16>(tmp->h);
 
 		switch (x_align) {
 		case TextAlignment_END:
diff --git a/SourceX/DiabloUI/ui_item.h b/SourceX/DiabloUI/ui_item.h
index 219f4559a..7a57e96c0 100644
--- a/SourceX/DiabloUI/ui_item.h
+++ b/SourceX/DiabloUI/ui_item.h
@@ -195,12 +195,12 @@ struct UiList : public UiItemBase {
 	template <std::size_t N>
 	constexpr UiList(
 	    UiListItem (&items)[N],
-	    decltype(SDL_Rect().x) x,
-	    decltype(SDL_Rect().y) y,
-	    decltype(SDL_Rect().w) item_width,
-	    decltype(SDL_Rect().h) item_height,
+	    Sint16 x,
+	    Sint16 y,
+	    Uint16 item_width,
+	    Uint16 item_height,
 	    int flags)
-	    : UiItemBase({ x, y, item_width, static_cast<decltype(SDL_Rect().h)>(item_height * N) }, flags)
+	    : UiItemBase({ x, y, item_width, static_cast<Uint16>(item_height * N) }, flags)
 	    , x(x)
 	    , y(y)
 	    , item_width(item_width)
@@ -210,19 +210,19 @@ struct UiList : public UiItemBase {
 	{
 	}
 
-	decltype(SDL_Rect().x) x;
-	decltype(SDL_Rect().y) y;
-	decltype(SDL_Rect().w) item_width;
-	decltype(SDL_Rect().h) item_height;
+	Sint16 x;
+	Sint16 y;
+	Uint16 item_width;
+	Uint16 item_height;
 	UiListItem *items;
 	std::size_t length;
 
 	SDL_Rect itemRect(std::size_t i) const
 	{
-		return { x, static_cast<decltype(SDL_Rect().y)>(y + item_height * i), item_width, item_height };
+		return { x, static_cast<Sint16>(y + item_height * i), item_width, item_height };
 	}
 
-	UiListItem *itemAt(decltype(SDL_Rect().y) y) const
+	UiListItem *itemAt(Sint16 y) const
 	{
 		ASSERT(y >= rect.y);
 		const std::size_t index = (y - rect.y) / item_height;
diff --git a/SourceX/storm/storm.cpp b/SourceX/storm/storm.cpp
index 39f6417d0..52370f706 100644
--- a/SourceX/storm/storm.cpp
+++ b/SourceX/storm/storm.cpp
@@ -719,14 +719,14 @@ BOOL SVidPlayContinue(void)
 		} else {
 			factor = wFactor;
 		}
-		const int scaledW = SVidWidth * factor;
-		const int scaledH = SVidHeight * factor;
+		const Sint16 scaledW = SVidWidth * factor;
+		const Sint16 scaledH = SVidHeight * factor;
 
 		SDL_Rect pal_surface_offset = {
-			static_cast<decltype(SDL_Rect().x)>((output_surface->w - scaledW) / 2),
-			static_cast<decltype(SDL_Rect().y)>((output_surface->h - scaledH) / 2),
-			static_cast<decltype(SDL_Rect().w)>(scaledW),
-			static_cast<decltype(SDL_Rect().h)>(scaledH)
+			(output_surface->w - scaledW) / 2,
+			(output_surface->h - scaledH) / 2,
+			scaledW,
+			scaledH
 		};
 		if (factor == 1) {
 			if (SDL_BlitSurface(SVidSurface, NULL, output_surface, &pal_surface_offset) <= -1) {