Function

CGAffineTransformMakeTranslation

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

Declaration

CGAffineTransform CGAffineTransformMakeTranslation(CGFloat tx, CGFloat ty);

Parameters

tx

The value by which to move the x-axis of the coordinate system.

ty

The value by which to move the y-axis of the coordinate system.

Return Value

A new affine transform matrix.

Discussion

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

A 3 by 3 matrix for translation.

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 apply the translation to a point (x,y):

Translation equations.

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

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.

CGAffineTransformMakeScale

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

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