Function

CGAffineTransformMakeScale

Returns an affine transformation matrix constructed from scaling values you provide.

Declaration

CGAffineTransform CGAffineTransformMakeScale(CGFloat sx, CGFloat sy);

Parameters

sx

The factor by which to scale the x-axis of the coordinate system.

sy

The factor by which to scale the y-axis of the coordinate system.

Return Value

A new affine transformation matrix.

Discussion

This function creates a CGAffineTransform structure, which you can use (and reuse, if you want) to scale a coordinate system. The matrix takes the following form:

A 3 by 3 matrix used to scale.

Because the third column is always (0,0,1), the CGAffineTransform data structure returned by this function contains values for only the first two columns.

These are the resulting equations used to scale the coordinates of a point (x,y):

Scaling equations.

If you want only to scale an object to be drawn, it is not necessary to construct an affine transform to do so. The most direct way to scale your drawing is by calling the function CGContextScaleCTM.

See Also

Creating an Affine Transformation Matrix

CGAffineTransformMake

Returns an affine transformation matrix constructed from values you provide.

CGAffineTransformMakeRotation

Returns an affine transformation matrix constructed from a rotation value you provide.

CGAffineTransformMakeTranslation

Returns an affine transformation matrix constructed from translation values you provide.