Newton Developer Technical Information: Newton Programmer's Guide: 2.1 OS Addendum /

Chapter 6 - Drawing and Graphics 2.1 / Drawing and Graphics Reference

Functions and Methods /

GetMaskedPixel

GetMaskedPixel(x, y, pixFamily) //Platform file function

Retrieves the value of a specific pixel within a pix family, taking into account its mask.

x

The x coordinate of the point to be tested, in local (view) coordinates.

y

The y coordinate of the point to be tested, in local (view) coordinates.

pixFamily

The pix family to test.

return value

An integer, -1 if the (x,y) pixel location lies outside the bounds of the pix family or if the mask is off at this position, otherwise the integer value of the specified pixel is returned (see below).

IMPORTANT

This function is not defined in all ROM versions and is supplied by the NTK Platform file. Call it using this syntax:

 call kGetMaskedPixelFunc with (x, y, pixFamily);

DISCUSSION

This function is similar to the existing PtInPicture function.

The value returned for a pixel that is actually within the pix family's bounds (and at an on position in the mask) depends on the bit depth of the pix family image. For images with a bit depth of 1, 2, 4, and 8, the pixel will be an index in the range [0, 2bit depth - 1]. For example, if the image has a bit depth of 4, the value returned by the function would range from 0 to 15. If the image has a bit depth of 16 or 32, the pixels will have a direct format, and the function will return the direct RGB pixel value.