PorterDuff.Mode  |  API reference  |  Android Developers (original) (raw)

class Mode

Known Direct Subclasses

PorterDuff.Mode.ADD, PorterDuff.Mode.CLEAR, PorterDuff.Mode.DARKEN, PorterDuff.Mode.DST, PorterDuff.Mode.DST_ATOP, PorterDuff.Mode.DST_IN, PorterDuff.Mode.DST_OUT, PorterDuff.Mode.DST_OVER, PorterDuff.Mode.LIGHTEN, PorterDuff.Mode.MULTIPLY, PorterDuff.Mode.OVERLAY, PorterDuff.Mode.SCREEN, and 6 others.

| PorterDuff.Mode.ADD | | | ----------------------------------------------------- | | | PorterDuff.Mode.CLEAR | | | PorterDuff.Mode.DARKEN | | | PorterDuff.Mode.DST | | | PorterDuff.Mode.DST_ATOP | | | PorterDuff.Mode.DST_IN | | | PorterDuff.Mode.DST_OUT | | | PorterDuff.Mode.DST_OVER | | | PorterDuff.Mode.LIGHTEN | | | PorterDuff.Mode.MULTIPLY | | | PorterDuff.Mode.OVERLAY | | | PorterDuff.Mode.SCREEN | | | PorterDuff.Mode.SRC | | | PorterDuff.Mode.SRC_ATOP | | | PorterDuff.Mode.SRC_IN | | | PorterDuff.Mode.SRC_OUT | | | PorterDuff.Mode.SRC_OVER | | | PorterDuff.Mode.XOR | |

The name of the parent class is an homage to the work of Thomas Porter and Tom Duff, presented in their seminal 1984 paper titled "Compositing Digital Images". In this paper, the authors describe 12 compositing operators that govern how to compute the color resulting of the composition of a source (the graphics object to render) with a destination (the content of the render target).

"Compositing Digital Images" was published in Computer Graphics Volume 18, Number 3 dated July 1984.

Because the work of Porter and Duff focuses solely on the effects of the alpha channel of the source and destination, the 12 operators described in the original paper are called alpha compositing modes here.

For convenience, this class also provides several blending modes, which similarly define the result of compositing a source and a destination but without being constrained to the alpha channel. These blending modes are not defined by Porter and Duff but have been included in this class for convenience purposes.

Diagrams

All the example diagrams presented below use the same source and destination images:

The order of drawing operations used to generate each diagram is shown in the following code snippet:

Paint paint = new Paint(); canvas.drawBitmap(destinationImage, 0, 0, paint);

PorterDuff.Mode mode = // choose a mode paint.setXfermode(new PorterDuffXfermode(mode));

canvas.drawBitmap(sourceImage, 0, 0, paint);

Alpha compositing modes

Blending modes

Compositing equations

The documentation of each individual alpha compositing or blending mode below provides the exact equation used to compute alpha and color value of the result of the composition of a source and destination.

The result (or output) alpha value is noted \(\alpha_{out}\). The result (or output) color value is noted \(C_{out}\).

Summary

Enum values

ADD

enum val ADD : PorterDuff.Mode

Adds the source pixels to the destination pixels and saturates the result.

\(\alpha_{out} = max(0, min(\alpha_{src} + \alpha_{dst}, 1))\)

\(C_{out} = max(0, min(C_{src} + C_{dst}, 1))\)

CLEAR

enum val CLEAR : PorterDuff.Mode

Destination pixels covered by the source are cleared to 0.

\(\alpha_{out} = 0\)

\(C_{out} = 0\)

DARKEN

enum val DARKEN : PorterDuff.Mode

Retains the smallest component of the source and destination pixels.

\(\alpha_{out} = \alpha_{src} + \alpha_{dst} - \alpha_{src} * \alpha_{dst}\)

\(C_{out} = (1 - \alpha_{dst}) * C_{src} + (1 - \alpha_{src}) * C_{dst} + min(C_{src}, C_{dst})\)

DST

enum val DST : PorterDuff.Mode

The source pixels are discarded, leaving the destination intact.

\(\alpha_{out} = \alpha_{dst}\)

\(C_{out} = C_{dst}\)

DST_ATOP

enum val DST_ATOP : PorterDuff.Mode

Discards the destination pixels that are not covered by source pixels. Draws remaining destination pixels over source pixels.

\(\alpha_{out} = \alpha_{src}\)

\(C_{out} = \alpha_{src} * C_{dst} + (1 - \alpha_{dst}) * C_{src}\)

DST_IN

enum val DST_IN : PorterDuff.Mode

Keeps the destination pixels that cover source pixels, discards the remaining source and destination pixels.

\(\alpha_{out} = \alpha_{src} * \alpha_{dst}\)

\(C_{out} = C_{dst} * \alpha_{src}\)

DST_OUT

enum val DST_OUT : PorterDuff.Mode

Keeps the destination pixels that are not covered by source pixels. Discards destination pixels that are covered by source pixels. Discards all source pixels.

\(\alpha_{out} = (1 - \alpha_{src}) * \alpha_{dst}\)

\(C_{out} = (1 - \alpha_{src}) * C_{dst}\)

DST_OVER

enum val DST_OVER : PorterDuff.Mode

The source pixels are drawn behind the destination pixels.

\(\alpha_{out} = \alpha_{dst} + (1 - \alpha_{dst}) * \alpha_{src}\)

\(C_{out} = C_{dst} + (1 - \alpha_{dst}) * C_{src}\)

LIGHTEN

enum val LIGHTEN : PorterDuff.Mode

Retains the largest component of the source and destination pixel.

\(\alpha_{out} = \alpha_{src} + \alpha_{dst} - \alpha_{src} * \alpha_{dst}\)

\(C_{out} = (1 - \alpha_{dst}) * C_{src} + (1 - \alpha_{src}) * C_{dst} + max(C_{src}, C_{dst})\)

MULTIPLY

enum val MULTIPLY : PorterDuff.Mode

Multiplies the source and destination pixels.

\(\alpha_{out} = \alpha_{src} * \alpha_{dst}\)

\(C_{out} = C_{src} * C_{dst}\)

OVERLAY

enum val OVERLAY : PorterDuff.Mode

Multiplies or screens the source and destination depending on the destination color.

\(\alpha_{out} = \alpha_{src} + \alpha_{dst} - \alpha_{src} * \alpha_{dst}\)

\(\begin{equation} C_{out} = \begin{cases} 2 * C_{src} * C_{dst} & 2 * C_{dst} \lt \alpha_{dst} \\ \alpha_{src} * \alpha_{dst} - 2 (\alpha_{dst} - C_{src}) (\alpha_{src} - C_{dst}) & otherwise \end{cases} \end{equation}\)

SCREEN

enum val SCREEN : PorterDuff.Mode

Adds the source and destination pixels, then subtracts the source pixels multiplied by the destination.

\(\alpha_{out} = \alpha_{src} + \alpha_{dst} - \alpha_{src} * \alpha_{dst}\)

\(C_{out} = C_{src} + C_{dst} - C_{src} * C_{dst}\)

SRC

enum val SRC : PorterDuff.Mode

The source pixels replace the destination pixels.

\(\alpha_{out} = \alpha_{src}\)

\(C_{out} = C_{src}\)

SRC_ATOP

enum val SRC_ATOP : PorterDuff.Mode

Discards the source pixels that do not cover destination pixels. Draws remaining source pixels over destination pixels.

\(\alpha_{out} = \alpha_{dst}\)

\(C_{out} = \alpha_{dst} * C_{src} + (1 - \alpha_{src}) * C_{dst}\)

SRC_IN

enum val SRC_IN : PorterDuff.Mode

Keeps the source pixels that cover the destination pixels, discards the remaining source and destination pixels.

\(\alpha_{out} = \alpha_{src} * \alpha_{dst}\)

\(C_{out} = C_{src} * \alpha_{dst}\)

SRC_OUT

enum val SRC_OUT : PorterDuff.Mode

Keeps the source pixels that do not cover destination pixels. Discards source pixels that cover destination pixels. Discards all destination pixels.

\(\alpha_{out} = (1 - \alpha_{dst}) * \alpha_{src}\)

\(C_{out} = (1 - \alpha_{dst}) * C_{src}\)

SRC_OVER

enum val SRC_OVER : PorterDuff.Mode

The source pixels are drawn over the destination pixels.

\(\alpha_{out} = \alpha_{src} + (1 - \alpha_{src}) * \alpha_{dst}\)

\(C_{out} = C_{src} + (1 - \alpha_{src}) * C_{dst}\)

XOR

enum val XOR : PorterDuff.Mode

Discards the source and destination pixels where source pixels cover destination pixels. Draws remaining source pixels.

\(\alpha_{out} = (1 - \alpha_{dst}) * \alpha_{src} + (1 - \alpha_{src}) * \alpha_{dst}\)

\(C_{out} = (1 - \alpha_{dst}) * C_{src} + (1 - \alpha_{src}) * C_{dst}\)