refactored 2D calcScaleToFit() function

src/ga/layout.h

@@ -106,7 +106,49 @@ inline vec3 calcScaleToFit( const vec3& sourceSize, const vec3& containerSize, c
 
 inline vec2 calcScaleToFit( const vec2& sourceSize, const vec2& containerSize, const FitMode& fitMode )
 {
-	return calcScaleToFit( vec3( sourceSize, 1.f ), vec3( containerSize, 1.f ), fitMode );
+	vec2 scale = vec2( 1.f );
+
+	// calculate sizing based on fit mode
+	switch ( fitMode ) {
+
+		case FitMode::FIT: {
+			vec2 s   = containerSize / sourceSize;
+			float s0 = std::min( s.x, s.y );
+			scale    = vec2( s0 );
+			break;
+		}
+
+		case FitMode::STRETCH: {
+			scale = containerSize / sourceSize;
+			break;
+		}
+
+		case FitMode::COVER: {
+			vec2 s   = containerSize / sourceSize;
+			float s1 = std::max( s.x, s.y );
+			scale    = vec2( s1 );
+			break;
+		}
+
+		case FitMode::FIT_WIDTH: {
+			float sx = containerSize.x / sourceSize.x;
+			scale    = vec2( sx );
+			break;
+		}
+
+		case FitMode::FIT_HEIGHT: {
+			float sy = containerSize.y / sourceSize.y;
+			scale    = vec2( sy );
+			break;
+		}
+
+		case FitMode::FIT_DEPTH:
+		case FitMode::NONE:
+		default:
+			break;
+	}
+
+	return scale;
 }
 
 }  // namespace ga