diff --git a/c++/perspective/src/generator.cpp b/c++/perspective/src/generator.cpp
index 4e0f23a..2e82651 100644
--- a/c++/perspective/src/generator.cpp
+++ b/c++/perspective/src/generator.cpp
@@ -364,7 +364,7 @@ Generator::generate(Surface &target, const Pair2 &bounds, bool checks) const {
 	Vector2 d = bounds.distance();
 	d.x /= w;
 	d.y /= h;
-	const Vector2 precision(fabs(d.x/2.0), fabs(d.x/2.0));
+	const Vector2 precision(fabs(d.x/2.0), fabs(d.y/2.0));
 	const Vector2 precision_inv(
 		1/std::max(precision.x, real_precision),
 		1/std::max(precision.y, real_precision) );
@@ -438,7 +438,7 @@ Generator::generate(Surface &target, const Pair2 &bounds, bool checks) const {
 			if (a + real_precision >= 1) {
 				*pixel = color;
 			} else {
-				const Color back_color = Color(1 - color.r, 1 - color.g, 1 - color.b, 1 - color.a);
+				const Color back_color = Color(color.g, color.b, color.r, color.a);
 				if (a - real_precision <= 0) {
 					*pixel = back_color;
 				} else {
diff --git a/c++/perspective/src/perspective.cpp b/c++/perspective/src/perspective.cpp
index a2b1ecc..f1a1ee0 100644
--- a/c++/perspective/src/perspective.cpp
+++ b/c++/perspective/src/perspective.cpp
@@ -194,20 +194,26 @@ Perspective::make_matrix(
 
 
 Matrix3
-Perspective::normalize_matrix_by_w(
-	const Matrix3 &matrix )
+Perspective::matrix_mult(
+	const Matrix3 &matrix,
+	Real value )
 {
-	Real k = matrix.get_col(2).length();
-	if (k <= real_precision)
-		return matrix;
-	k = 1/k;
 	Matrix3 m = matrix;
 	for(int i = 0; i < 9; ++i)
-		m.a[i] *= k;
+		m.a[i] *= value;
 	return m;
 }
 
 
+Matrix3
+Perspective::normalize_matrix_by_det(
+	const Matrix3 &matrix )
+{
+	const Real d = matrix.det();
+	return fabs(d) <= real_precision ? matrix : matrix_mult(matrix, fabs(1/cbrt(d)));
+}
+
+
 int
 Perspective::truncate_line(
 	Vector2 *out_points,
@@ -276,11 +282,23 @@ Perspective::calc_optimal_resolution(
 	
 	const Real sum = a*d + b*c;
 	Vector2 scale;
-	if (2*a*b + real_precision_sqr >= sum) {
+	bool abgt = (2*a*b + real_precision_sqr >= sum);
+	bool cdgt = (2*c*d + real_precision_sqr >= sum);
+	
+	if (abgt && cdgt) {
+		if (a*b < c*d) {
+			scale.x = sqrt(2*b)*e;
+			scale.y = sqrt(2*a)*e;
+		} else {
+			scale.x = sqrt(2*d)*e;
+			scale.y = sqrt(2*c)*e;
+		}
+	} else
+	if (abgt) {
 		scale.x = sqrt(2*b)*e;
 		scale.y = sqrt(2*a)*e;
 	} else
-	if (2*c*d + real_precision_sqr >= sum) {
+	if (cdgt) {
 		scale.x = sqrt(2*d)*e;
 		scale.y = sqrt(2*c)*e;
 	} else {
@@ -383,8 +401,8 @@ Perspective::create_layers(
 	const Real step )
 {
 	bool is_invertible = false;
-	Matrix3 norm_matrix = normalize_matrix_by_w(matrix);
-	Matrix3 back_matrix = norm_matrix.inverted(&is_invertible);
+	Matrix3 norm_matrix = normalize_matrix_by_det(matrix);
+	Matrix3 back_matrix = normalize_matrix_by_det( norm_matrix.inverted(&is_invertible) );
 	if (!is_invertible)
 		return; // matrix is collapsed
 	
@@ -407,6 +425,7 @@ Perspective::create_layers(
 		
 		if (fabs(C) < real_precision)
 			return; // only when matrix was not invertible (additional check)
+		back_matrix = matrix_mult(back_matrix, 1/C);
 		
 		// calc src resolution
 		const Vector2 resolution = calc_optimal_resolution(
diff --git a/c++/perspective/src/perspective.h b/c++/perspective/src/perspective.h
index d9eced0..a92dad2 100644
--- a/c++/perspective/src/perspective.h
+++ b/c++/perspective/src/perspective.h
@@ -30,7 +30,10 @@ public:
 		const Vector2 &py,
 		const Vector2 &p1 );
 	
-	static Matrix3 normalize_matrix_by_w(
+	static Matrix3 matrix_mult(
+		const Matrix3 &matrix,
+		Real value );
+	static Matrix3 normalize_matrix_by_det(
 		const Matrix3 &matrix );
 
 	static int truncate_line(
diff --git a/c++/perspective/src/perspectivesandboxview.cpp b/c++/perspective/src/perspectivesandboxview.cpp
index 4687875..93361d5 100644
--- a/c++/perspective/src/perspectivesandboxview.cpp
+++ b/c++/perspective/src/perspectivesandboxview.cpp
@@ -379,7 +379,7 @@ PerspectiveSandBoxView::on_draw_view(const Cairo::RefPtr<Cairo::Context> &contex
 			Vector3( m4.m00, m4.m01, m4.m03 ),
 			Vector3( m4.m10, m4.m11, m4.m13 ),
 			Vector3( m4.m30, m4.m31, m4.m33 ) );
-		Matrix3 back_matrix = Perspective::normalize_matrix_by_w( m3.inverted() );
+		Matrix3 back_matrix = Perspective::normalize_matrix_by_det( m3.inverted() );
 		update_background_best_perimeter(back_matrix, get_width(), get_height());
 	}