set_matrix


Description:

public void set_matrix (Matrix matrix)

Example: Cartesian coordinate system (II):

public static int main (string[] args) {
// Create a context:
Cairo.ImageSurface surface = new Cairo.ImageSurface (Cairo.Format.ARGB32, 500, 500);
Cairo.Context context = new Cairo.Context (surface);

// Transformations:
Cairo.Matrix matrix = Cairo.Matrix.identity ();
matrix.translate (250, 250);
matrix.scale (1, -1);

context.set_matrix (matrix);

// Y-Axis:
context.move_to (-250, 0);
context.line_to (250, 0);
context.stroke ();

// X-Axis:
context.move_to (0, -250);
context.line_to (0, 250);
context.stroke ();

// P (20, 10)
context.set_source_rgba (0, 0, 0, 1);
context.arc (20, 10, 2, 0, 2*Math.PI);
context.fill ();

// Save the image:
surface.write_to_png ("img.png");

return 0;
}

valac --pkg cairo cartesian-coordinate-system-matrix.vala