svg preserveAspectRatio="xMidYMid":
xMidYMid—uniform scaling, aligning to the middle.
xMinYMin—uniform scaling, aligning to the top-left.
xMaxYMax—uniform scaling, aligning to the bottom-right.
circle cx="100" cy="100" r="100":
cx—the centre “x” coordinate.
cy—the centre “y” coordinate.
r—the radius of the circle (half its width).
ellipse cx="100" cy="100" rx="100" ry="50":
cx—the centre “x” coordinate.
cy—the centre “y” coordinate.
rx—the horizontal radius of the oval (half its width).
ry—the verical radius of the oval (half its height).
rect x="0" y="0" width="256" height="64" rx="5" ry="5":
x—the top left corner’s “x” coordinate.
y—the top left corder’s “y” coordinate.
width—the horizontal size of the rectangle.
height—the vertical size of the rectangle.
rx—for adding rounded corners; the horizontal radius of the rounding circle.
ry—for adding rounded corners; the vertical radius of the rounding circle.