ryan/mozjpeg
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Document -rgb option in djpeg man page; "gray-scale"="grayscale"

Browse Source 
git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1294 632fc199-4ca6-4c93-a231-07263d6284db
This commit is contained in:
DRC
2014-05-12 09:09:40 +00:00
parent 2a9f0cf36c 90d6c3824b
commit 6e8220eddc
6 changed files with 24 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
README
View File

@@ -62,7 +62,7 @@ OVERVIEW
This package contains C software to implement JPEG image encoding, decoding,
and transcoding. JPEG (pronounced "jay-peg") is a standardized compression
method for full-color and gray-scale images. JPEG's strong suit is compressing
method for full-color and grayscale images. JPEG's strong suit is compressing
photographic images or other types of images that have smooth color and
brightness transitions between neighboring pixels. Images with sharp lines or
other abrupt features may not compress well with JPEG, and a higher JPEG

2
cjpeg.1
View File

@@ -16,7 +16,7 @@ cjpeg \- compress an image file to a JPEG file
compresses the named image file, or the standard input if no file is
named, and produces a JPEG/JFIF file on the standard output.
The currently supported input file formats are: PPM (PBMPLUS color
format), PGM (PBMPLUS gray-scale format), BMP, Targa, and RLE (Utah Raster
format), PGM (PBMPLUS grayscale format), BMP, Targa, and RLE (Utah Raster
Toolkit format). (RLE is supported only if the URT library is available.)
.SH OPTIONS
All switch names may be abbreviated; for example,

17
djpeg.1
View File

@@ -55,11 +55,14 @@ default options are chosen for highest quality output.) Currently, this is
equivalent to \fB\-dct fast \-nosmooth \-onepass \-dither ordered\fR.
.TP
.B \-grayscale
Force gray-scale output even if JPEG file is color. Useful for viewing on
Force grayscale output even if JPEG file is color. Useful for viewing on
monochrome displays; also,
.B djpeg
runs noticeably faster in this mode.
.TP
.B \-rgb
Force RGB output even if JPEG file is grayscale.
.TP
.BI \-scale " M/N"
Scale the output image by a factor M/N. Currently the scale factor must be
M/8, where M is an integer between 1 and 16 inclusive, or any reduced fraction
@@ -74,7 +77,7 @@ emitted if
.B \-colors
or
.B \-grayscale
is specified, or if the JPEG file is gray-scale; otherwise, 24-bit full-color
is specified, or if the JPEG file is grayscale; otherwise, 24-bit full-color
format is emitted.
.TP
.B \-gif
@@ -88,12 +91,12 @@ emitted if
.B \-colors
or
.B \-grayscale
is specified, or if the JPEG file is gray-scale; otherwise, 24-bit full-color
is specified, or if the JPEG file is grayscale; otherwise, 24-bit full-color
format is emitted.
.TP
.B \-pnm
Select PBMPLUS (PPM/PGM) output format (this is the default format).
PGM is emitted if the JPEG file is gray-scale or if
PGM is emitted if the JPEG file is grayscale or if
.B \-grayscale
is specified; otherwise PPM is emitted.
.TP
@@ -101,8 +104,8 @@ is specified; otherwise PPM is emitted.
Select RLE output format. (Requires URT library.)
.TP
.B \-targa
Select Targa output format. Gray-scale format is emitted if the JPEG file is
gray-scale or if
Select Targa output format. Grayscale format is emitted if the JPEG file is
grayscale or if
.B \-grayscale
is specified; otherwise, colormapped format is emitted if
.B \-colors
@@ -174,7 +177,7 @@ faster and needs less memory, but it produces a lower-quality image.
is ignored unless you also say
.B \-colors
.IR N .
Also, the one-pass method is always used for gray-scale output (the two-pass
Also, the one-pass method is always used for grayscale output (the two-pass
method is no improvement then).
.TP
.BI \-maxmemory " N"

18
usage.txt
View File

@@ -17,7 +17,7 @@ INTRODUCTION
These programs implement JPEG image encoding, decoding, and transcoding.
JPEG (pronounced "jay-peg") is a standardized compression method for
full-color and gray-scale images.
full-color and grayscale images.
GENERAL USAGE
@@ -50,7 +50,7 @@ or
This syntax works on all systems, so it is useful for scripts.
The currently supported image file formats are: PPM (PBMPLUS color format),
PGM (PBMPLUS gray-scale format), BMP, Targa, and RLE (Utah Raster Toolkit
PGM (PBMPLUS grayscale format), BMP, Targa, and RLE (Utah Raster Toolkit
format). (RLE is supported only if the URT library is available.)
cjpeg recognizes the input image format automatically, with the exception
of some Targa-format files. You have to tell djpeg which format to generate.
@@ -271,7 +271,7 @@ The basic command line switches for djpeg are:
highest quality output.) Currently, this is equivalent
to "-dct fast -nosmooth -onepass -dither ordered".
-grayscale Force gray-scale output even if JPEG file is color.
-grayscale Force grayscale output even if JPEG file is color.
Useful for viewing on monochrome displays; also,
djpeg runs noticeably faster in this mode.
@@ -284,7 +284,7 @@ The basic command line switches for djpeg are:
-bmp Select BMP output format (Windows flavor). 8-bit
colormapped format is emitted if -colors or -grayscale
is specified, or if the JPEG file is gray-scale;
is specified, or if the JPEG file is grayscale;
otherwise, 24-bit full-color format is emitted.
-gif Select GIF output format. Since GIF does not support
@@ -294,18 +294,18 @@ The basic command line switches for djpeg are:
-os2 Select BMP output format (OS/2 1.x flavor). 8-bit
colormapped format is emitted if -colors or -grayscale
is specified, or if the JPEG file is gray-scale;
is specified, or if the JPEG file is grayscale;
otherwise, 24-bit full-color format is emitted.
-pnm Select PBMPLUS (PPM/PGM) output format (this is the
default format). PGM is emitted if the JPEG file is
gray-scale or if -grayscale is specified; otherwise
grayscale or if -grayscale is specified; otherwise
PPM is emitted.
-rle Select RLE output format. (Requires URT library.)
-targa Select Targa output format. Gray-scale format is
emitted if the JPEG file is gray-scale or if
-targa Select Targa output format. Grayscale format is
emitted if the JPEG file is grayscale or if
-grayscale is specified; otherwise, colormapped format
is emitted if -colors is specified; otherwise, 24-bit
full-color format is emitted.
@@ -367,7 +367,7 @@ Switches for advanced users:
The one-pass method is faster and needs less memory,
but it produces a lower-quality image. -onepass is
ignored unless you also say -colors N. Also,
the one-pass method is always used for gray-scale
the one-pass method is always used for grayscale
output (the two-pass method is no improvement then).
-maxmemory N Set limit for amount of memory to use in processing

4
wrgif.c
View File

@@ -218,7 +218,7 @@ put_3bytes (gif_dest_ptr dinfo, int val)
LOCAL(void)
emit_header (gif_dest_ptr dinfo, int num_colors, JSAMPARRAY colormap)
/* Output the GIF file header, including color map */
/* If colormap==NULL, synthesize a gray-scale colormap */
/* If colormap==NULL, synthesize a grayscale colormap */
{
int BitsPerPixel, ColorMapSize, InitCodeSize, FlagByte;
int cshift = dinfo->cinfo->data_precision - 8;
@@ -270,7 +270,7 @@ emit_header (gif_dest_ptr dinfo, int num_colors, JSAMPARRAY colormap)
put_3bytes(dinfo, GETJSAMPLE(colormap[0][i]) >> cshift);
}
} else {
/* Create a gray-scale map of num_colors values, range 0..255 */
/* Create a grayscale map of num_colors values, range 0..255 */
put_3bytes(dinfo, (i * 255 + (num_colors-1)/2) / (num_colors-1));
}
} else {

2
wrtarga.c
View File

@@ -73,7 +73,7 @@ write_header (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, int num_colors)
targaheader[17] = 0x20; /* Top-down, non-interlaced */
if (cinfo->out_color_space == JCS_GRAYSCALE) {
targaheader[2] = 3; /* image type = uncompressed gray-scale */
targaheader[2] = 3; /* image type = uncompressed grayscale */
targaheader[16] = 8; /* bits per pixel */
} else { /* must be RGB */
if (num_colors > 0) {