Release Notes

Open Source Used In AsyncOS 8.8 for Cisco Web Security Appliances

UINT8 JFIF_minor_version

UINT8 density_unitResolution data from JFIF marker

UINT16 X_density

UINT16 Y_density

boolean saw_Adobe_markerTRUE if an Adobe APP14 marker was seen

UINT8 Adobe_transformColor transform code from Adobe marker

The JPEG color space, unfortunately, is something of a guess since the JPEG

standard proper does not provide a way to record it. In practice most files

adhere to the JFIF or Adobe conventions, and the decoder will recognize these

correctly. See "Special color spaces", below, for more info.

The decompression parameters that determine the basic properties of the

returned image are:

J_COLOR_SPACE out_color_space

Output color space. jpeg_read_header() sets an appropriate default

based on jpeg_color_space; typically it will be RGB or grayscale.

The application can change this field to request output in a different

colorspace. For example, set it to JCS_GRAYSCALE to get grayscale

output from a color file. (This is useful for previewing: grayscale

output is faster than full color since the color components need not

be processed.) Note that not all possible color space transforms are

currently implemented; you may need to extend jdcolor.c if you want an

unusual conversion.

unsigned int scale_num, scale_denom

Scale the image by the fraction scale_num/scale_denom. Currently,

the supported scaling ratios are M/N with all M from 1 to 16, where

N is the source DCT size, which is 8 for baseline JPEG. (The library

design allows for arbitrary scaling ratios but this is not likely

to be implemented any time soon.) The values are initialized by

jpeg_read_header() with the source DCT size. For baseline JPEG

this is 8/8. If you change only the scale_num value while leaving

the other unchanged, then this specifies the DCT scaled size to be

applied on the given input. For baseline JPEG this is equivalent

to M/8 scaling, since the source DCT size for baseline JPEG is 8.

Smaller scaling ratios permit significantly faster decoding since

fewer pixels need be processed and a simpler IDCT method can be used.

boolean quantize_colors

If set TRUE, colormapped output will be delivered. Default is FALSE,

meaning that full-color output will be delivered.

The next three parameters are relevant only if quantize_colors is TRUE.

int desired_number_of_colors