Function

CGContextSetShadow

Enables shadowing in a graphics context.

Declaration

void CGContextSetShadow(CGContextRef c, CGSize offset, CGFloat blur);

Parameters

context

A graphics context.

offset

Specifies a translation of the context’s coordinate system, to establish an offset for the shadow ({0,0} specifies a light source immediately above the screen).

blur

A non-negative number specifying the amount of blur.

Discussion

Shadow parameters are part of the graphics state in a context. After shadowing is set, all objects drawn are shadowed using a black color with 1/3 alpha (in effect, RGBA = {0, 0, 0, 1.0/3.0}) in the DeviceRGB color space.

To turn off shadowing:

  • Use the standard save/restore mechanism for the graphics state.

  • Use CGContextSetShadowWithColor to set the shadow color to a fully transparent color (or pass NULL as the color).

See Also

Setting Color, Color Space, and Shadow Values

CGContextSetAlpha

Sets the opacity level for objects drawn in a graphics context.

CGContextSetCMYKFillColor

Sets the current fill color to a value in the DeviceCMYK color space.

CGContextSetFillColor

Sets the current fill color.

CGContextSetCMYKStrokeColor

Sets the current stroke color to a value in the DeviceCMYK color space.

CGContextSetFillColorSpace

Sets the fill color space in a graphics context.

CGContextSetFillColorWithColor

Sets the current fill color in a graphics context, using a CGColor.

CGContextSetGrayFillColor

Sets the current fill color to a value in the DeviceGray color space.

CGContextSetGrayStrokeColor

Sets the current stroke color to a value in the DeviceGray color space.

CGContextSetRGBFillColor

Sets the current fill color to a value in the DeviceRGB color space.

CGContextSetRGBStrokeColor

Sets the current stroke color to a value in the DeviceRGB color space.

CGContextSetShadowWithColor

Enables shadowing with color a graphics context.

CGContextSetStrokeColor

Sets the current stroke color.

CGContextSetStrokeColorSpace

Sets the stroke color space in a graphics context.

CGContextSetStrokeColorWithColor

Sets the current stroke color in a context, using a CGColor.