SkMatrix matrix; matrix.setAll(1.0f); // Sets all elements to 1.0f SkMatrix identity; identity.setAll(1.0f); identity.setAll(0, 1.0f); // Sets the diagonal elements to 1.0f float values[9] = {1, 2, 3, 4, 5, 6, 7, 8, 9}; SkMatrix custom(values); custom.setAll(0.0f); // Sets all elements to 0.0fThis function is part of the Skia library, which is a cross-platform 2D graphics library written in C++.