maskData

Specifies which pixels of an image are displayed.

# Metadata

Platforms: desktop, server, mobile OS: mac, windows, linux, ios, android Introduced: 1.1 Security:

# Syntax

set the maskData of image to binaryData

# Examples

put the maskData of image "Download" into dataToAnalyze

# Description

Use the maskData property to change the appearance of an image without changing its image data, or to examine the mask of the image.

Each pixel is represented by 8 bits (1 byte) of mask data, with pixels numbered from the top left corner of the image, left to right, then top to bottom.

Since each pixel is represented by 8 bits (1 byte or 1 character), you can obtain the numeric value for a given pixel using the charToNum function. For example, the numeric value of the maskData for the tenth pixel is given by the expression charToNum(char 10 of the mask of image).

A value of zero means the pixel is fully transparent; any other value means the pixel is fully opaque. Unlike the alphaData property, the maskData stores only complete transparency or complete opacity, and does not support partial transparency.

# Tags

multimedia,

# See

- **keyword:** image - **property:** pixels, windowShape, alphaData - **glossary:** property, pixel, binary, mask, expression - **control structure:** function